root/sys/dev/ntb/ntb_hw/ntb_hw_intel.c
/*-
 * Copyright (c) 2016-2017 Alexander Motin <mav@FreeBSD.org>
 * Copyright (C) 2013 Intel Corporation
 * Copyright (C) 2015 EMC Corporation
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * The Non-Transparent Bridge (NTB) is a device that allows you to connect
 * two or more systems using a PCI-e links, providing remote memory access.
 *
 * This module contains a driver for NTB hardware in Intel Xeon/Atom CPUs.
 *
 * NOTE: Much of the code in this module is shared with Linux. Any patches may
 * be picked up and redistributed in Linux with a dual GPL/BSD license.
 */

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/endian.h>
#include <sys/interrupt.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/pciio.h>
#include <sys/taskqueue.h>
#include <sys/tree.h>
#include <sys/queue.h>
#include <sys/rman.h>
#include <sys/sbuf.h>
#include <sys/sysctl.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include <machine/bus.h>
#include <machine/intr_machdep.h>
#include <machine/resource.h>
#include <dev/pci/pcireg.h>
#include <dev/pci/pcivar.h>
#include <dev/iommu/iommu.h>

#include "ntb_hw_intel.h"
#include "../ntb.h"

#define MAX_MSIX_INTERRUPTS     \
        MAX(MAX(XEON_DB_COUNT, ATOM_DB_COUNT), XEON_GEN3_DB_COUNT)

#define NTB_HB_TIMEOUT          1 /* second */
#define ATOM_LINK_RECOVERY_TIME 500 /* ms */
#define BAR_HIGH_MASK           (~((1ull << 12) - 1))

#define NTB_MSIX_VER_GUARD      0xaabbccdd
#define NTB_MSIX_RECEIVED       0xe0f0e0f0

/*
 * PCI constants could be somewhere more generic, but aren't defined/used in
 * pci.c.
 */
#define PCI_MSIX_ENTRY_SIZE             16
#define PCI_MSIX_ENTRY_LOWER_ADDR       0
#define PCI_MSIX_ENTRY_UPPER_ADDR       4
#define PCI_MSIX_ENTRY_DATA             8

enum ntb_device_type {
        NTB_XEON_GEN1,
        NTB_XEON_GEN3,
        NTB_XEON_GEN4,
        NTB_ATOM
};

/* ntb_conn_type are hardware numbers, cannot change. */
enum ntb_conn_type {
        NTB_CONN_TRANSPARENT = 0,
        NTB_CONN_B2B = 1,
        NTB_CONN_RP = 2,
};

enum ntb_b2b_direction {
        NTB_DEV_USD = 0,
        NTB_DEV_DSD = 1,
};

enum ntb_bar {
        NTB_CONFIG_BAR = 0,
        NTB_B2B_BAR_1,
        NTB_B2B_BAR_2,
        NTB_B2B_BAR_3,
        NTB_MAX_BARS
};

enum {
        NTB_MSIX_GUARD = 0,
        NTB_MSIX_DATA0,
        NTB_MSIX_DATA1,
        NTB_MSIX_DATA2,
        NTB_MSIX_OFS0,
        NTB_MSIX_OFS1,
        NTB_MSIX_OFS2,
        NTB_MSIX_DONE,
        NTB_MAX_MSIX_SPAD
};

/* Device features and workarounds */
#define HAS_FEATURE(ntb, feature)       \
        (((ntb)->features & (feature)) != 0)

struct ntb_hw_info {
        uint32_t                device_id;
        const char              *desc;
        enum ntb_device_type    type;
        uint32_t                features;
};

struct ntb_pci_bar_info {
        bus_space_tag_t         pci_bus_tag;
        bus_space_handle_t      pci_bus_handle;
        int                     pci_resource_id;
        struct resource         *pci_resource;
        vm_paddr_t              pbase;
        caddr_t                 vbase;
        vm_size_t               size;
        vm_memattr_t            map_mode;

        /* Configuration register offsets */
        uint32_t                psz_off;
        uint32_t                ssz_off;
        uint32_t                pbarxlat_off;
};

struct ntb_int_info {
        struct resource *res;
        int             rid;
        void            *tag;
};

struct ntb_vec {
        struct ntb_softc        *ntb;
        uint32_t                num;
        unsigned                masked;
};

struct ntb_reg {
        uint32_t        ntb_ctl;
        uint32_t        lnk_sta;
        uint8_t         db_size;
        unsigned        mw_bar[NTB_MAX_BARS];
};

struct ntb_alt_reg {
        uint32_t        db_bell;
        uint32_t        db_mask;
        uint32_t        db_clear;
        uint32_t        spad;
};

struct ntb_xlat_reg {
        uint32_t        bar0_base;
        uint32_t        bar2_base;
        uint32_t        bar4_base;
        uint32_t        bar5_base;

        uint32_t        bar2_xlat;
        uint32_t        bar4_xlat;
        uint32_t        bar5_xlat;

        uint32_t        bar2_limit;
        uint32_t        bar4_limit;
        uint32_t        bar5_limit;
};

struct ntb_b2b_addr {
        uint64_t        bar0_addr;
        uint64_t        bar2_addr64;
        uint64_t        bar4_addr64;
        uint64_t        bar4_addr32;
        uint64_t        bar5_addr32;
};

struct ntb_msix_data {
        uint32_t        nmd_ofs;
        uint32_t        nmd_data;
};

struct ntb_softc {
        /* ntb.c context. Do not move! Must go first! */
        void                    *ntb_store;

        device_t                device;
        enum ntb_device_type    type;
        uint32_t                features;

        struct ntb_pci_bar_info bar_info[NTB_MAX_BARS];
        struct ntb_int_info     int_info[MAX_MSIX_INTERRUPTS];
        uint32_t                allocated_interrupts;

        struct ntb_msix_data    peer_msix_data[XEON_NONLINK_DB_MSIX_BITS];
        struct ntb_msix_data    msix_data[XEON_NONLINK_DB_MSIX_BITS];
        bool                    peer_msix_good;
        bool                    peer_msix_done;
        struct ntb_pci_bar_info *peer_lapic_bar;
        struct callout          peer_msix_work;

        bus_dma_tag_t           bar0_dma_tag;
        bus_dmamap_t            bar0_dma_map;

        struct callout          heartbeat_timer;
        struct callout          lr_timer;

        struct ntb_vec          *msix_vec;

        uint32_t                ppd;
        enum ntb_conn_type      conn_type;
        enum ntb_b2b_direction  dev_type;

        /* Offset of peer bar0 in B2B BAR */
        uint64_t                        b2b_off;
        /* Memory window used to access peer bar0 */
#define B2B_MW_DISABLED                 UINT8_MAX
        uint8_t                         b2b_mw_idx;
        uint32_t                        msix_xlat;
        uint8_t                         msix_mw_idx;

        uint8_t                         mw_count;
        uint8_t                         spad_count;
        uint8_t                         db_count;
        uint8_t                         db_vec_count;
        uint8_t                         db_vec_shift;

        /* Protects local db_mask. */
#define DB_MASK_LOCK(sc)        mtx_lock_spin(&(sc)->db_mask_lock)
#define DB_MASK_UNLOCK(sc)      mtx_unlock_spin(&(sc)->db_mask_lock)
#define DB_MASK_ASSERT(sc,f)    mtx_assert(&(sc)->db_mask_lock, (f))
        struct mtx                      db_mask_lock;

        volatile uint32_t               ntb_ctl;
        volatile uint32_t               lnk_sta;

        uint64_t                        db_valid_mask;
        uint64_t                        db_link_mask;
        uint64_t                        db_mask;
        uint64_t                        fake_db;        /* NTB_SB01BASE_LOCKUP*/
        uint64_t                        force_db;       /* NTB_SB01BASE_LOCKUP*/

        int                             last_ts;        /* ticks @ last irq */

        const struct ntb_reg            *reg;
        const struct ntb_alt_reg        *self_reg;
        const struct ntb_alt_reg        *peer_reg;
        const struct ntb_xlat_reg       *xlat_reg;
};

#ifdef __i386__
static __inline uint64_t
bus_space_read_8(bus_space_tag_t tag, bus_space_handle_t handle,
    bus_size_t offset)
{

        return (bus_space_read_4(tag, handle, offset) |
            ((uint64_t)bus_space_read_4(tag, handle, offset + 4)) << 32);
}

static __inline void
bus_space_write_8(bus_space_tag_t tag, bus_space_handle_t handle,
    bus_size_t offset, uint64_t val)
{

        bus_space_write_4(tag, handle, offset, val);
        bus_space_write_4(tag, handle, offset + 4, val >> 32);
}
#endif

#define intel_ntb_bar_read(SIZE, bar, offset) \
            bus_space_read_ ## SIZE (ntb->bar_info[(bar)].pci_bus_tag, \
            ntb->bar_info[(bar)].pci_bus_handle, (offset))
#define intel_ntb_bar_write(SIZE, bar, offset, val) \
            bus_space_write_ ## SIZE (ntb->bar_info[(bar)].pci_bus_tag, \
            ntb->bar_info[(bar)].pci_bus_handle, (offset), (val))
#define intel_ntb_reg_read(SIZE, offset) \
            intel_ntb_bar_read(SIZE, NTB_CONFIG_BAR, offset)
#define intel_ntb_reg_write(SIZE, offset, val) \
            intel_ntb_bar_write(SIZE, NTB_CONFIG_BAR, offset, val)
#define intel_ntb_mw_read(SIZE, offset) \
            intel_ntb_bar_read(SIZE, intel_ntb_mw_to_bar(ntb, ntb->b2b_mw_idx), \
                offset)
#define intel_ntb_mw_write(SIZE, offset, val) \
            intel_ntb_bar_write(SIZE, intel_ntb_mw_to_bar(ntb, ntb->b2b_mw_idx), \
                offset, val)

static int intel_ntb_probe(device_t device);
static int intel_ntb_attach(device_t device);
static int intel_ntb_detach(device_t device);
static uint64_t intel_ntb_db_valid_mask(device_t dev);
static void intel_ntb_spad_clear(device_t dev);
static uint64_t intel_ntb_db_vector_mask(device_t dev, uint32_t vector);
static bool intel_ntb_link_is_up(device_t dev, enum ntb_speed *speed,
    enum ntb_width *width);
static int intel_ntb_link_enable(device_t dev, enum ntb_speed speed,
    enum ntb_width width);
static int intel_ntb_link_disable(device_t dev);
static int intel_ntb_spad_read(device_t dev, unsigned int idx, uint32_t *val);
static int intel_ntb_peer_spad_write(device_t dev, unsigned int idx, uint32_t val);

static unsigned intel_ntb_user_mw_to_idx(struct ntb_softc *, unsigned uidx);
static inline enum ntb_bar intel_ntb_mw_to_bar(struct ntb_softc *, unsigned mw);
static inline bool bar_is_64bit(struct ntb_softc *, enum ntb_bar);
static inline void bar_get_xlat_params(struct ntb_softc *, enum ntb_bar,
    uint32_t *base, uint32_t *xlat, uint32_t *lmt);
static int intel_ntb_map_pci_bars(struct ntb_softc *ntb);
static int intel_ntb_mw_set_wc_internal(struct ntb_softc *, unsigned idx,
    vm_memattr_t);
static void print_map_success(struct ntb_softc *, struct ntb_pci_bar_info *,
    const char *);
static int map_mmr_bar(struct ntb_softc *ntb, struct ntb_pci_bar_info *bar);
static int map_memory_window_bar(struct ntb_softc *ntb,
    struct ntb_pci_bar_info *bar);
static void intel_ntb_unmap_pci_bar(struct ntb_softc *ntb);
static int intel_ntb_remap_msix(device_t, uint32_t desired, uint32_t avail);
static int intel_ntb_init_isr(struct ntb_softc *ntb);
static int intel_ntb_xeon_gen3_init_isr(struct ntb_softc *ntb);
static int intel_ntb_setup_legacy_interrupt(struct ntb_softc *ntb);
static int intel_ntb_setup_msix(struct ntb_softc *ntb, uint32_t num_vectors);
static void intel_ntb_teardown_interrupts(struct ntb_softc *ntb);
static inline uint64_t intel_ntb_vec_mask(struct ntb_softc *, uint64_t db_vector);
static void intel_ntb_interrupt(struct ntb_softc *, uint32_t vec);
static void ndev_vec_isr(void *arg);
static void ndev_irq_isr(void *arg);
static inline uint64_t db_ioread(struct ntb_softc *, uint64_t regoff);
static inline void db_iowrite(struct ntb_softc *, uint64_t regoff, uint64_t);
static inline void db_iowrite_raw(struct ntb_softc *, uint64_t regoff, uint64_t);
static int intel_ntb_create_msix_vec(struct ntb_softc *ntb, uint32_t num_vectors);
static void intel_ntb_free_msix_vec(struct ntb_softc *ntb);
static void intel_ntb_get_msix_info(struct ntb_softc *ntb);
static void intel_ntb_exchange_msix(void *);
static struct ntb_hw_info *intel_ntb_get_device_info(uint32_t device_id);
static void intel_ntb_detect_max_mw(struct ntb_softc *ntb);
static int intel_ntb_detect_xeon(struct ntb_softc *ntb);
static int intel_ntb_detect_xeon_gen3(struct ntb_softc *ntb);
static int intel_ntb_detect_xeon_gen4(struct ntb_softc *ntb);
static int intel_ntb_detect_xeon_gen4_cfg(struct ntb_softc *ntb);
static int intel_ntb_detect_atom(struct ntb_softc *ntb);
static int intel_ntb_xeon_init_dev(struct ntb_softc *ntb);
static int intel_ntb_xeon_gen3_init_dev(struct ntb_softc *ntb);
static int intel_ntb_xeon_gen4_init_dev(struct ntb_softc *ntb);
static int intel_ntb_atom_init_dev(struct ntb_softc *ntb);
static void intel_ntb_teardown_xeon(struct ntb_softc *ntb);
static void configure_atom_secondary_side_bars(struct ntb_softc *ntb);
static void xeon_reset_sbar_size(struct ntb_softc *, enum ntb_bar idx,
    enum ntb_bar regbar);
static void xeon_set_sbar_base_and_limit(struct ntb_softc *,
    uint64_t base_addr, enum ntb_bar idx, enum ntb_bar regbar);
static void xeon_set_pbar_xlat(struct ntb_softc *, uint64_t base_addr,
    enum ntb_bar idx);
static int xeon_setup_b2b_mw(struct ntb_softc *,
    const struct ntb_b2b_addr *addr, const struct ntb_b2b_addr *peer_addr);
static int xeon_gen3_setup_b2b_mw(struct ntb_softc *);
static int xeon_gen4_setup_b2b_mw(struct ntb_softc *);
static int intel_ntb_mw_set_trans(device_t dev, unsigned idx, bus_addr_t addr,
    size_t size);
static inline bool link_is_up(struct ntb_softc *ntb);
static inline bool _xeon_link_is_up(struct ntb_softc *ntb);
static inline bool atom_link_is_err(struct ntb_softc *ntb);
static inline enum ntb_speed intel_ntb_link_sta_speed(struct ntb_softc *);
static inline enum ntb_width intel_ntb_link_sta_width(struct ntb_softc *);
static void atom_link_hb(void *arg);
static void recover_atom_link(void *arg);
static bool intel_ntb_poll_link(struct ntb_softc *ntb);
static void save_bar_parameters(struct ntb_pci_bar_info *bar);
static void intel_ntb_sysctl_init(struct ntb_softc *);
static int sysctl_handle_features(SYSCTL_HANDLER_ARGS);
static int sysctl_handle_link_admin(SYSCTL_HANDLER_ARGS);
static int sysctl_handle_link_status_human(SYSCTL_HANDLER_ARGS);
static int sysctl_handle_link_status(SYSCTL_HANDLER_ARGS);
static int sysctl_handle_register(SYSCTL_HANDLER_ARGS);

static unsigned g_ntb_hw_debug_level;
SYSCTL_UINT(_hw_ntb, OID_AUTO, debug_level, CTLFLAG_RWTUN,
    &g_ntb_hw_debug_level, 0, "ntb_hw log level -- higher is more verbose");
#define intel_ntb_printf(lvl, ...) do {                         \
        if ((lvl) <= g_ntb_hw_debug_level) {                    \
                device_printf(ntb->device, __VA_ARGS__);        \
        }                                                       \
} while (0)

#define _NTB_PAT_UC     0
#define _NTB_PAT_WC     1
#define _NTB_PAT_WT     4
#define _NTB_PAT_WP     5
#define _NTB_PAT_WB     6
#define _NTB_PAT_UCM    7
static unsigned g_ntb_mw_pat = _NTB_PAT_UC;
SYSCTL_UINT(_hw_ntb, OID_AUTO, default_mw_pat, CTLFLAG_RDTUN,
    &g_ntb_mw_pat, 0, "Configure the default memory window cache flags (PAT): "
    "UC: "  __XSTRING(_NTB_PAT_UC) ", "
    "WC: "  __XSTRING(_NTB_PAT_WC) ", "
    "WT: "  __XSTRING(_NTB_PAT_WT) ", "
    "WP: "  __XSTRING(_NTB_PAT_WP) ", "
    "WB: "  __XSTRING(_NTB_PAT_WB) ", "
    "UC-: " __XSTRING(_NTB_PAT_UCM));

static inline vm_memattr_t
intel_ntb_pat_flags(void)
{

        switch (g_ntb_mw_pat) {
        case _NTB_PAT_WC:
                return (VM_MEMATTR_WRITE_COMBINING);
        case _NTB_PAT_WT:
                return (VM_MEMATTR_WRITE_THROUGH);
        case _NTB_PAT_WP:
                return (VM_MEMATTR_WRITE_PROTECTED);
        case _NTB_PAT_WB:
                return (VM_MEMATTR_WRITE_BACK);
        case _NTB_PAT_UCM:
                return (VM_MEMATTR_WEAK_UNCACHEABLE);
        case _NTB_PAT_UC:
                /* FALLTHROUGH */
        default:
                return (VM_MEMATTR_UNCACHEABLE);
        }
}

/*
 * Well, this obviously doesn't belong here, but it doesn't seem to exist
 * anywhere better yet.
 */
static inline const char *
intel_ntb_vm_memattr_to_str(vm_memattr_t pat)
{

        switch (pat) {
        case VM_MEMATTR_WRITE_COMBINING:
                return ("WRITE_COMBINING");
        case VM_MEMATTR_WRITE_THROUGH:
                return ("WRITE_THROUGH");
        case VM_MEMATTR_WRITE_PROTECTED:
                return ("WRITE_PROTECTED");
        case VM_MEMATTR_WRITE_BACK:
                return ("WRITE_BACK");
        case VM_MEMATTR_WEAK_UNCACHEABLE:
                return ("UNCACHED");
        case VM_MEMATTR_UNCACHEABLE:
                return ("UNCACHEABLE");
        default:
                return ("UNKNOWN");
        }
}

static int g_ntb_msix_idx = 1;
SYSCTL_INT(_hw_ntb, OID_AUTO, msix_mw_idx, CTLFLAG_RDTUN, &g_ntb_msix_idx,
    0, "Use this memory window to access the peer MSIX message complex on "
    "certain Xeon-based NTB systems, as a workaround for a hardware errata.  "
    "Like b2b_mw_idx, negative values index from the last available memory "
    "window.  (Applies on Xeon platforms with SB01BASE_LOCKUP errata.)");

static int g_ntb_mw_idx = -1;
SYSCTL_INT(_hw_ntb, OID_AUTO, b2b_mw_idx, CTLFLAG_RDTUN, &g_ntb_mw_idx,
    0, "Use this memory window to access the peer NTB registers.  A "
    "non-negative value starts from the first MW index; a negative value "
    "starts from the last MW index.  The default is -1, i.e., the last "
    "available memory window.  Both sides of the NTB MUST set the same "
    "value here!  (Applies on Xeon platforms with SDOORBELL_LOCKUP errata.)");

/* Hardware owns the low 16 bits of features. */
#define NTB_BAR_SIZE_4K         (1 << 0)
#define NTB_SDOORBELL_LOCKUP    (1 << 1)
#define NTB_SB01BASE_LOCKUP     (1 << 2)
#define NTB_B2BDOORBELL_BIT14   (1 << 3)
#define NTB_BAR_ALIGN           (1 << 4)
#define NTB_LTR_BAD                     (1 << 5)
/* Software/configuration owns the top 16 bits. */
#define NTB_SPLIT_BAR           (1ull << 16)
#define NTB_ONE_MSIX            (1ull << 17)

#define NTB_FEATURES_STR \
    "\20\21SPLIT_BAR4\06LTR_BAD\05BAR_ALIGN"  \
        "\04B2B_DOORBELL_BIT14\03SB01BASE_LOCKUP" \
    "\02SDOORBELL_LOCKUP\01BAR_SIZE_4K"

static struct ntb_hw_info pci_ids[] = {
        /* XXX: PS/SS IDs left out until they are supported. */
        { 0x0C4E8086, "BWD Atom Processor S1200 Non-Transparent Bridge B2B",
                NTB_ATOM, 0 },

        { 0x37258086, "JSF Xeon C35xx/C55xx Non-Transparent Bridge B2B",
                NTB_XEON_GEN1, NTB_SDOORBELL_LOCKUP | NTB_B2BDOORBELL_BIT14 },
        { 0x3C0D8086, "SNB Xeon E5/Core i7 Non-Transparent Bridge B2B",
                NTB_XEON_GEN1, NTB_SDOORBELL_LOCKUP | NTB_B2BDOORBELL_BIT14 },
        { 0x0E0D8086, "IVT Xeon E5 V2 Non-Transparent Bridge B2B",
                NTB_XEON_GEN1, NTB_SDOORBELL_LOCKUP | NTB_B2BDOORBELL_BIT14 |
                    NTB_SB01BASE_LOCKUP | NTB_BAR_SIZE_4K },
        { 0x2F0D8086, "HSX Xeon E5 V3 Non-Transparent Bridge B2B",
                NTB_XEON_GEN1, NTB_SDOORBELL_LOCKUP | NTB_B2BDOORBELL_BIT14 |
                    NTB_SB01BASE_LOCKUP },
        { 0x6F0D8086, "BDX Xeon E5 V4 Non-Transparent Bridge B2B",
                NTB_XEON_GEN1, NTB_SDOORBELL_LOCKUP | NTB_B2BDOORBELL_BIT14 |
                    NTB_SB01BASE_LOCKUP },

        { 0x201C8086, "SKL Xeon E5 V5 Non-Transparent Bridge B2B",
                NTB_XEON_GEN3, 0 },

        { 0x347e8086, "ICX/SPR Xeon Non-Transparent Bridge B2B",
            NTB_XEON_GEN4, 0 },
};

static const struct ntb_reg atom_reg = {
        .ntb_ctl = ATOM_NTBCNTL_OFFSET,
        .lnk_sta = ATOM_LINK_STATUS_OFFSET,
        .db_size = sizeof(uint64_t),
        .mw_bar = { NTB_B2B_BAR_1, NTB_B2B_BAR_2 },
};

static const struct ntb_alt_reg atom_pri_reg = {
        .db_bell = ATOM_PDOORBELL_OFFSET,
        .db_mask = ATOM_PDBMSK_OFFSET,
        .spad = ATOM_SPAD_OFFSET,
};

static const struct ntb_alt_reg atom_b2b_reg = {
        .db_bell = ATOM_B2B_DOORBELL_OFFSET,
        .spad = ATOM_B2B_SPAD_OFFSET,
};

static const struct ntb_xlat_reg atom_sec_xlat = {
#if 0
        /* "FIXME" says the Linux driver. */
        .bar0_base = ATOM_SBAR0BASE_OFFSET,
        .bar2_base = ATOM_SBAR2BASE_OFFSET,
        .bar4_base = ATOM_SBAR4BASE_OFFSET,

        .bar2_limit = ATOM_SBAR2LMT_OFFSET,
        .bar4_limit = ATOM_SBAR4LMT_OFFSET,
#endif

        .bar2_xlat = ATOM_SBAR2XLAT_OFFSET,
        .bar4_xlat = ATOM_SBAR4XLAT_OFFSET,
};

static const struct ntb_reg xeon_reg = {
        .ntb_ctl = XEON_NTBCNTL_OFFSET,
        .lnk_sta = XEON_LINK_STATUS_OFFSET,
        .db_size = sizeof(uint16_t),
        .mw_bar = { NTB_B2B_BAR_1, NTB_B2B_BAR_2, NTB_B2B_BAR_3 },
};

static const struct ntb_alt_reg xeon_pri_reg = {
        .db_bell = XEON_PDOORBELL_OFFSET,
        .db_mask = XEON_PDBMSK_OFFSET,
        .spad = XEON_SPAD_OFFSET,
};

static const struct ntb_alt_reg xeon_b2b_reg = {
        .db_bell = XEON_B2B_DOORBELL_OFFSET,
        .spad = XEON_B2B_SPAD_OFFSET,
};

static const struct ntb_xlat_reg xeon_sec_xlat = {
        .bar0_base = XEON_SBAR0BASE_OFFSET,
        .bar2_base = XEON_SBAR2BASE_OFFSET,
        .bar4_base = XEON_SBAR4BASE_OFFSET,
        .bar5_base = XEON_SBAR5BASE_OFFSET,

        .bar2_limit = XEON_SBAR2LMT_OFFSET,
        .bar4_limit = XEON_SBAR4LMT_OFFSET,
        .bar5_limit = XEON_SBAR5LMT_OFFSET,

        .bar2_xlat = XEON_SBAR2XLAT_OFFSET,
        .bar4_xlat = XEON_SBAR4XLAT_OFFSET,
        .bar5_xlat = XEON_SBAR5XLAT_OFFSET,
};

static struct ntb_b2b_addr xeon_b2b_usd_addr = {
        .bar0_addr = XEON_B2B_BAR0_ADDR,
        .bar2_addr64 = XEON_B2B_BAR2_ADDR64,
        .bar4_addr64 = XEON_B2B_BAR4_ADDR64,
        .bar4_addr32 = XEON_B2B_BAR4_ADDR32,
        .bar5_addr32 = XEON_B2B_BAR5_ADDR32,
};

static struct ntb_b2b_addr xeon_b2b_dsd_addr = {
        .bar0_addr = XEON_B2B_BAR0_ADDR,
        .bar2_addr64 = XEON_B2B_BAR2_ADDR64,
        .bar4_addr64 = XEON_B2B_BAR4_ADDR64,
        .bar4_addr32 = XEON_B2B_BAR4_ADDR32,
        .bar5_addr32 = XEON_B2B_BAR5_ADDR32,
};

static const struct ntb_reg xeon_gen3_reg = {
        .ntb_ctl = XEON_GEN3_REG_IMNTB_CTRL,
        .lnk_sta = XEON_GEN3_INT_LNK_STS_OFFSET,
        .db_size = sizeof(uint32_t),
        .mw_bar = { NTB_B2B_BAR_1, NTB_B2B_BAR_2 },
};

static const struct ntb_alt_reg xeon_gen3_pri_reg = {
        .db_bell = XEON_GEN3_REG_EMDOORBELL,
        .db_mask = XEON_GEN3_REG_IMINT_DISABLE,
        .spad = XEON_GEN3_REG_IMSPAD,
};

static const struct ntb_alt_reg xeon_gen3_b2b_reg = {
        .db_bell = XEON_GEN3_REG_IMDOORBELL,
        .db_mask = XEON_GEN3_REG_EMINT_DISABLE,
        .spad = XEON_GEN3_REG_IMB2B_SSPAD,
};

static const struct ntb_xlat_reg xeon_gen3_sec_xlat = {
        .bar0_base = XEON_GEN3_EXT_REG_BAR0BASE,
        .bar2_base = XEON_GEN3_EXT_REG_BAR1BASE,
        .bar4_base = XEON_GEN3_EXT_REG_BAR2BASE,

        .bar2_limit = XEON_GEN3_REG_IMBAR1XLIMIT,
        .bar4_limit = XEON_GEN3_REG_IMBAR2XLIMIT,

        .bar2_xlat = XEON_GEN3_REG_IMBAR1XBASE,
        .bar4_xlat = XEON_GEN3_REG_IMBAR2XBASE,
};

static const struct ntb_reg xeon_gen4_reg = {
        .ntb_ctl = XEON_GEN4_REG_IMNTB_CTL,
        .lnk_sta = XEON_GEN4_REG_LINK_STATUS, /* mmio */
        .db_size = sizeof(uint32_t),
        .mw_bar = { NTB_B2B_BAR_1, NTB_B2B_BAR_2 },
};

static const struct ntb_alt_reg xeon_gen4_pri_reg = {
        .db_clear = XEON_GEN4_REG_IMINT_STATUS,
        .db_mask = XEON_GEN4_REG_IMINT_DISABLE,
        .spad = XEON_GEN4_REG_IMSPAD,
};

static const struct ntb_alt_reg xeon_gen4_b2b_reg = {
        .db_bell = XEON_GEN4_REG_IMDOORBELL,
        .spad = XEON_GEN4_REG_EMSPAD,
};

static const struct ntb_xlat_reg xeon_gen4_sec_xlat = {
        .bar2_limit = XEON_GEN4_REG_IMBAR1XLIMIT,
        .bar2_xlat = XEON_GEN4_REG_IMBAR1XBASE,

        .bar4_limit = XEON_GEN4_REG_IMBAR1XLIMIT,
        .bar4_xlat = XEON_GEN4_REG_IMBAR2XBASE,
};

SYSCTL_NODE(_hw_ntb, OID_AUTO, xeon_b2b, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "B2B MW segment overrides -- MUST be the same on both sides");

SYSCTL_UQUAD(_hw_ntb_xeon_b2b, OID_AUTO, usd_bar2_addr64, CTLFLAG_RDTUN,
    &xeon_b2b_usd_addr.bar2_addr64, 0, "If using B2B topology on Xeon "
    "hardware, use this 64-bit address on the bus between the NTB devices for "
    "the window at BAR2, on the upstream side of the link.  MUST be the same "
    "address on both sides.");
SYSCTL_UQUAD(_hw_ntb_xeon_b2b, OID_AUTO, usd_bar4_addr64, CTLFLAG_RDTUN,
    &xeon_b2b_usd_addr.bar4_addr64, 0, "See usd_bar2_addr64, but BAR4.");
SYSCTL_UQUAD(_hw_ntb_xeon_b2b, OID_AUTO, usd_bar4_addr32, CTLFLAG_RDTUN,
    &xeon_b2b_usd_addr.bar4_addr32, 0, "See usd_bar2_addr64, but BAR4 "
    "(split-BAR mode).");
SYSCTL_UQUAD(_hw_ntb_xeon_b2b, OID_AUTO, usd_bar5_addr32, CTLFLAG_RDTUN,
    &xeon_b2b_usd_addr.bar5_addr32, 0, "See usd_bar2_addr64, but BAR5 "
    "(split-BAR mode).");

SYSCTL_UQUAD(_hw_ntb_xeon_b2b, OID_AUTO, dsd_bar2_addr64, CTLFLAG_RDTUN,
    &xeon_b2b_dsd_addr.bar2_addr64, 0, "If using B2B topology on Xeon "
    "hardware, use this 64-bit address on the bus between the NTB devices for "
    "the window at BAR2, on the downstream side of the link.  MUST be the same"
    " address on both sides.");
SYSCTL_UQUAD(_hw_ntb_xeon_b2b, OID_AUTO, dsd_bar4_addr64, CTLFLAG_RDTUN,
    &xeon_b2b_dsd_addr.bar4_addr64, 0, "See dsd_bar2_addr64, but BAR4.");
SYSCTL_UQUAD(_hw_ntb_xeon_b2b, OID_AUTO, dsd_bar4_addr32, CTLFLAG_RDTUN,
    &xeon_b2b_dsd_addr.bar4_addr32, 0, "See dsd_bar2_addr64, but BAR4 "
    "(split-BAR mode).");
SYSCTL_UQUAD(_hw_ntb_xeon_b2b, OID_AUTO, dsd_bar5_addr32, CTLFLAG_RDTUN,
    &xeon_b2b_dsd_addr.bar5_addr32, 0, "See dsd_bar2_addr64, but BAR5 "
    "(split-BAR mode).");

/*
 * OS <-> Driver interface structures
 */
MALLOC_DEFINE(M_NTB, "ntb_hw", "ntb_hw driver memory allocations");

/*
 * OS <-> Driver linkage functions
 */
static int
intel_ntb_probe(device_t device)
{
        struct ntb_hw_info *p;

        p = intel_ntb_get_device_info(pci_get_devid(device));
        if (p == NULL)
                return (ENXIO);

        device_set_desc(device, p->desc);
        return (0);
}

static int
intel_ntb_attach(device_t device)
{
        struct ntb_softc *ntb;
        struct ntb_hw_info *p;
        int error;

        ntb = device_get_softc(device);
        p = intel_ntb_get_device_info(pci_get_devid(device));

        ntb->device = device;
        ntb->type = p->type;
        ntb->features = p->features;
        ntb->b2b_mw_idx = B2B_MW_DISABLED;
        ntb->msix_mw_idx = B2B_MW_DISABLED;

        /* Heartbeat timer for NTB_ATOM since there is no link interrupt */
        callout_init(&ntb->heartbeat_timer, 1);
        callout_init(&ntb->lr_timer, 1);
        callout_init(&ntb->peer_msix_work, 1);
        mtx_init(&ntb->db_mask_lock, "ntb hw bits", NULL, MTX_SPIN);

        if (ntb->type == NTB_ATOM)
                error = intel_ntb_detect_atom(ntb);
        else if (ntb->type == NTB_XEON_GEN3)
                error = intel_ntb_detect_xeon_gen3(ntb);
        else if (ntb->type == NTB_XEON_GEN4)
                error = intel_ntb_detect_xeon_gen4(ntb);
        else
                error = intel_ntb_detect_xeon(ntb);
        if (error != 0)
                goto out;

        intel_ntb_detect_max_mw(ntb);

        pci_enable_busmaster(ntb->device);

        error = intel_ntb_map_pci_bars(ntb);
        if (error != 0)
                goto out;
        if (ntb->type == NTB_ATOM)
                error = intel_ntb_atom_init_dev(ntb);
        else if (ntb->type == NTB_XEON_GEN3)
                error = intel_ntb_xeon_gen3_init_dev(ntb);
        else if (ntb->type == NTB_XEON_GEN4)
                error = intel_ntb_xeon_gen4_init_dev(ntb);
        else
                error = intel_ntb_xeon_init_dev(ntb);
        if (error != 0)
                goto out;

        intel_ntb_spad_clear(device);

        intel_ntb_poll_link(ntb);

        intel_ntb_sysctl_init(ntb);

        /* Attach children to this controller */
        error = ntb_register_device(device);

out:
        if (error != 0)
                intel_ntb_detach(device);
        return (error);
}

static int
intel_ntb_detach(device_t device)
{
        struct ntb_softc *ntb;

        ntb = device_get_softc(device);

        /* Detach & delete all children */
        ntb_unregister_device(device);

        if (ntb->self_reg != NULL) {
                DB_MASK_LOCK(ntb);
                db_iowrite(ntb, ntb->self_reg->db_mask, ntb->db_valid_mask);
                DB_MASK_UNLOCK(ntb);
        }
        callout_drain(&ntb->heartbeat_timer);
        callout_drain(&ntb->lr_timer);
        callout_drain(&ntb->peer_msix_work);
        pci_disable_busmaster(ntb->device);
        if (ntb->type == NTB_XEON_GEN1)
                intel_ntb_teardown_xeon(ntb);
        intel_ntb_teardown_interrupts(ntb);

        mtx_destroy(&ntb->db_mask_lock);

        intel_ntb_unmap_pci_bar(ntb);

        return (0);
}

/*
 * Driver internal routines
 */
static inline enum ntb_bar
intel_ntb_mw_to_bar(struct ntb_softc *ntb, unsigned mw)
{

        KASSERT(mw < ntb->mw_count,
            ("%s: mw:%u > count:%u", __func__, mw, (unsigned)ntb->mw_count));
        KASSERT(ntb->reg->mw_bar[mw] != 0, ("invalid mw"));

        return (ntb->reg->mw_bar[mw]);
}

static inline bool
bar_is_64bit(struct ntb_softc *ntb, enum ntb_bar bar)
{
        /* XXX This assertion could be stronger. */
        KASSERT(bar < NTB_MAX_BARS, ("bogus bar"));
        return (bar < NTB_B2B_BAR_2 || !HAS_FEATURE(ntb, NTB_SPLIT_BAR));
}

static inline void
bar_get_xlat_params(struct ntb_softc *ntb, enum ntb_bar bar, uint32_t *base,
    uint32_t *xlat, uint32_t *lmt)
{
        uint32_t basev, lmtv, xlatv;

        switch (bar) {
        case NTB_B2B_BAR_1:
                basev = ntb->xlat_reg->bar2_base;
                lmtv = ntb->xlat_reg->bar2_limit;
                xlatv = ntb->xlat_reg->bar2_xlat;
                break;
        case NTB_B2B_BAR_2:
                basev = ntb->xlat_reg->bar4_base;
                lmtv = ntb->xlat_reg->bar4_limit;
                xlatv = ntb->xlat_reg->bar4_xlat;
                break;
        case NTB_B2B_BAR_3:
                basev = ntb->xlat_reg->bar5_base;
                lmtv = ntb->xlat_reg->bar5_limit;
                xlatv = ntb->xlat_reg->bar5_xlat;
                break;
        default:
                KASSERT(bar >= NTB_B2B_BAR_1 && bar < NTB_MAX_BARS,
                    ("bad bar"));
                basev = lmtv = xlatv = 0;
                break;
        }

        if (base != NULL)
                *base = basev;
        if (xlat != NULL)
                *xlat = xlatv;
        if (lmt != NULL)
                *lmt = lmtv;
}

static int
intel_ntb_map_pci_bars(struct ntb_softc *ntb)
{
        struct ntb_pci_bar_info *bar;
        int rc;

        bar = &ntb->bar_info[NTB_CONFIG_BAR];
        bar->pci_resource_id = PCIR_BAR(0);
        rc = map_mmr_bar(ntb, bar);
        if (rc != 0)
                goto out;

        /*
         * At least on Xeon v4 NTB device leaks to host some remote side
         * BAR0 writes supposed to update scratchpad registers.  I am not
         * sure why it happens, but it may be related to the fact that
         * on a link side BAR0 is 32KB, while on a host side it is 64KB.
         * Without this hack DMAR blocks those accesses as not allowed.
         */
        if (bus_dma_tag_create(bus_get_dma_tag(ntb->device), 1, 0,
            BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR, NULL, NULL,
            bar->size, 1, bar->size, 0, NULL, NULL, &ntb->bar0_dma_tag)) {
                device_printf(ntb->device, "Unable to create BAR0 tag\n");
                return (ENOMEM);
        }
        if (bus_dmamap_create(ntb->bar0_dma_tag, 0, &ntb->bar0_dma_map)) {
                device_printf(ntb->device, "Unable to create BAR0 map\n");
                return (ENOMEM);
        }
        if (bus_dma_iommu_load_ident(ntb->bar0_dma_tag, ntb->bar0_dma_map,
            bar->pbase, bar->size, 0)) {
                device_printf(ntb->device, "Unable to load BAR0 map\n");
                return (ENOMEM);
        }

        bar = &ntb->bar_info[NTB_B2B_BAR_1];
        bar->pci_resource_id = PCIR_BAR(2);
        rc = map_memory_window_bar(ntb, bar);
        if (rc != 0)
                goto out;
        if (ntb->type == NTB_XEON_GEN3) {
                bar->psz_off = XEON_GEN3_INT_REG_IMBAR1SZ;
                bar->ssz_off = XEON_GEN3_INT_REG_EMBAR1SZ;
                bar->pbarxlat_off = XEON_GEN3_REG_EMBAR1XBASE;
        } else if (ntb->type == NTB_XEON_GEN4) {
                bar->psz_off = XEON_GEN4_CFG_REG_IMBAR1SZ;
                bar->ssz_off = XEON_GEN4_CFG_REG_EMBAR1SZ;
                bar->pbarxlat_off = XEON_GEN4_REG_EXT_BAR1BASE;
        } else {
                bar->psz_off = XEON_PBAR23SZ_OFFSET;
                bar->ssz_off = XEON_SBAR23SZ_OFFSET;
                bar->pbarxlat_off = XEON_PBAR2XLAT_OFFSET;
        }

        bar = &ntb->bar_info[NTB_B2B_BAR_2];
        bar->pci_resource_id = PCIR_BAR(4);
        rc = map_memory_window_bar(ntb, bar);
        if (rc != 0)
                goto out;
        if (ntb->type == NTB_XEON_GEN3) {
                bar->psz_off = XEON_GEN3_INT_REG_IMBAR2SZ;
                bar->ssz_off = XEON_GEN3_INT_REG_EMBAR2SZ;
                bar->pbarxlat_off = XEON_GEN3_REG_EMBAR2XBASE;
        } else if (ntb->type == NTB_XEON_GEN4) {
                bar->psz_off = XEON_GEN4_CFG_REG_IMBAR2SZ;
                bar->ssz_off = XEON_GEN4_CFG_REG_EMBAR2SZ;
                bar->pbarxlat_off = XEON_GEN4_REG_EXT_BAR2BASE;
        } else {
                bar->psz_off = XEON_PBAR4SZ_OFFSET;
                bar->ssz_off = XEON_SBAR4SZ_OFFSET;
                bar->pbarxlat_off = XEON_PBAR4XLAT_OFFSET;
        }

        if (!HAS_FEATURE(ntb, NTB_SPLIT_BAR))
                goto out;

        if (ntb->type == NTB_XEON_GEN3 ||
            ntb->type == NTB_XEON_GEN4) {
                device_printf(ntb->device, "no split bar support\n");
                return (ENXIO);
        }

        bar = &ntb->bar_info[NTB_B2B_BAR_3];
        bar->pci_resource_id = PCIR_BAR(5);
        rc = map_memory_window_bar(ntb, bar);
        bar->psz_off = XEON_PBAR5SZ_OFFSET;
        bar->ssz_off = XEON_SBAR5SZ_OFFSET;
        bar->pbarxlat_off = XEON_PBAR5XLAT_OFFSET;

out:
        if (rc != 0)
                device_printf(ntb->device,
                    "unable to allocate pci resource\n");
        return (rc);
}

static void
print_map_success(struct ntb_softc *ntb, struct ntb_pci_bar_info *bar,
    const char *kind)
{

        device_printf(ntb->device,
            "Mapped BAR%d v:[%p-%p] p:[0x%jx-0x%jx] (0x%jx bytes) (%s)\n",
            PCI_RID2BAR(bar->pci_resource_id), bar->vbase,
            (char *)bar->vbase + bar->size - 1,
            (uintmax_t)bar->pbase, (uintmax_t)(bar->pbase + bar->size - 1),
            (uintmax_t)bar->size, kind);
}

static int
map_mmr_bar(struct ntb_softc *ntb, struct ntb_pci_bar_info *bar)
{

        bar->pci_resource = bus_alloc_resource_any(ntb->device, SYS_RES_MEMORY,
            &bar->pci_resource_id, RF_ACTIVE);
        if (bar->pci_resource == NULL)
                return (ENXIO);

        save_bar_parameters(bar);
        bar->map_mode = VM_MEMATTR_UNCACHEABLE;
        print_map_success(ntb, bar, "mmr");
        return (0);
}

static int
map_memory_window_bar(struct ntb_softc *ntb, struct ntb_pci_bar_info *bar)
{
        int rc;
        vm_memattr_t mapmode;
        uint8_t bar_size_bits = 0;

        bar->pci_resource = bus_alloc_resource_any(ntb->device, SYS_RES_MEMORY,
            &bar->pci_resource_id, RF_ACTIVE);

        if (bar->pci_resource == NULL)
                return (ENXIO);

        save_bar_parameters(bar);
        /*
         * Ivytown NTB BAR sizes are misreported by the hardware due to a
         * hardware issue. To work around this, query the size it should be
         * configured to by the device and modify the resource to correspond to
         * this new size. The BIOS on systems with this problem is required to
         * provide enough address space to allow the driver to make this change
         * safely.
         *
         * Ideally I could have just specified the size when I allocated the
         * resource like:
         *  bus_alloc_resource(ntb->device,
         *      SYS_RES_MEMORY, &bar->pci_resource_id, 0ul, ~0ul,
         *      1ul << bar_size_bits, RF_ACTIVE);
         * but the PCI driver does not honor the size in this call, so we have
         * to modify it after the fact.
         */
        if (HAS_FEATURE(ntb, NTB_BAR_SIZE_4K)) {
                if (bar->pci_resource_id == PCIR_BAR(2))
                        bar_size_bits = pci_read_config(ntb->device,
                            XEON_PBAR23SZ_OFFSET, 1);
                else
                        bar_size_bits = pci_read_config(ntb->device,
                            XEON_PBAR45SZ_OFFSET, 1);

                rc = bus_adjust_resource(ntb->device, SYS_RES_MEMORY,
                    bar->pci_resource, bar->pbase,
                    bar->pbase + (1ul << bar_size_bits) - 1);
                if (rc != 0) {
                        device_printf(ntb->device,
                            "unable to resize bar\n");
                        return (rc);
                }

                save_bar_parameters(bar);
        }

        bar->map_mode = VM_MEMATTR_UNCACHEABLE;
        print_map_success(ntb, bar, "mw");

        /*
         * Optionally, mark MW BARs as anything other than UC to improve
         * performance.
         */
        mapmode = intel_ntb_pat_flags();
        if (mapmode == bar->map_mode)
                return (0);

        rc = pmap_change_attr(bar->vbase, bar->size, mapmode);
        if (rc == 0) {
                bar->map_mode = mapmode;
                device_printf(ntb->device,
                    "Marked BAR%d v:[%p-%p] p:[0x%jx-0x%jx] as "
                    "%s.\n",
                    PCI_RID2BAR(bar->pci_resource_id), bar->vbase,
                    (char *)bar->vbase + bar->size - 1,
                    (uintmax_t)bar->pbase,
                    (uintmax_t)(bar->pbase + bar->size - 1),
                    intel_ntb_vm_memattr_to_str(mapmode));
        } else
                device_printf(ntb->device,
                    "Unable to mark BAR%d v:[%p-%p] p:[0x%jx-0x%jx] as "
                    "%s: %d\n",
                    PCI_RID2BAR(bar->pci_resource_id), bar->vbase,
                    (char *)bar->vbase + bar->size - 1,
                    (uintmax_t)bar->pbase,
                    (uintmax_t)(bar->pbase + bar->size - 1),
                    intel_ntb_vm_memattr_to_str(mapmode), rc);
                /* Proceed anyway */
        return (0);
}

static void
intel_ntb_unmap_pci_bar(struct ntb_softc *ntb)
{
        struct ntb_pci_bar_info *bar;
        int i;

        if (ntb->bar0_dma_map != NULL) {
                bus_dmamap_unload(ntb->bar0_dma_tag, ntb->bar0_dma_map);
                bus_dmamap_destroy(ntb->bar0_dma_tag, ntb->bar0_dma_map);
        }
        if (ntb->bar0_dma_tag != NULL)
                bus_dma_tag_destroy(ntb->bar0_dma_tag);
        for (i = 0; i < NTB_MAX_BARS; i++) {
                bar = &ntb->bar_info[i];
                if (bar->pci_resource != NULL)
                        bus_release_resource(ntb->device, SYS_RES_MEMORY,
                            bar->pci_resource_id, bar->pci_resource);
        }
}

static int
intel_ntb_setup_msix(struct ntb_softc *ntb, uint32_t num_vectors)
{
        uint32_t i;
        int rc;

        for (i = 0; i < num_vectors; i++) {
                ntb->int_info[i].rid = i + 1;
                ntb->int_info[i].res = bus_alloc_resource_any(ntb->device,
                    SYS_RES_IRQ, &ntb->int_info[i].rid, RF_ACTIVE);
                if (ntb->int_info[i].res == NULL) {
                        device_printf(ntb->device,
                            "bus_alloc_resource failed\n");
                        return (ENOMEM);
                }
                ntb->int_info[i].tag = NULL;
                ntb->allocated_interrupts++;
                rc = bus_setup_intr(ntb->device, ntb->int_info[i].res,
                    INTR_MPSAFE | INTR_TYPE_MISC, NULL, ndev_vec_isr,
                    &ntb->msix_vec[i], &ntb->int_info[i].tag);
                if (rc != 0) {
                        device_printf(ntb->device, "bus_setup_intr failed\n");
                        return (ENXIO);
                }
        }
        return (0);
}

/*
 * The Linux NTB driver drops from MSI-X to legacy INTx if a unique vector
 * cannot be allocated for each MSI-X message.  JHB seems to think remapping
 * should be okay.  This tunable should enable us to test that hypothesis
 * when someone gets their hands on some Xeon hardware.
 */
static int ntb_force_remap_mode;
SYSCTL_INT(_hw_ntb, OID_AUTO, force_remap_mode, CTLFLAG_RDTUN,
    &ntb_force_remap_mode, 0, "If enabled, force MSI-X messages to be remapped"
    " to a smaller number of ithreads, even if the desired number are "
    "available");

/*
 * In case it is NOT ok, give consumers an abort button.
 */
static int ntb_prefer_intx;
SYSCTL_INT(_hw_ntb, OID_AUTO, prefer_intx_to_remap, CTLFLAG_RDTUN,
    &ntb_prefer_intx, 0, "If enabled, prefer to use legacy INTx mode rather "
    "than remapping MSI-X messages over available slots (match Linux driver "
    "behavior)");

/*
 * Remap the desired number of MSI-X messages to available ithreads in a simple
 * round-robin fashion.
 */
static int
intel_ntb_remap_msix(device_t dev, uint32_t desired, uint32_t avail)
{
        u_int *vectors;
        uint32_t i;
        int rc;

        if (ntb_prefer_intx != 0)
                return (ENXIO);

        vectors = malloc(desired * sizeof(*vectors), M_NTB, M_ZERO | M_WAITOK);

        for (i = 0; i < desired; i++)
                vectors[i] = (i % avail) + 1;

        rc = pci_remap_msix(dev, desired, vectors);
        free(vectors, M_NTB);
        return (rc);
}

static int
intel_ntb_xeon_gen3_init_isr(struct ntb_softc *ntb)
{
        uint64_t i, reg;
        uint32_t desired_vectors, num_vectors;
        int rc;

        ntb->allocated_interrupts = 0;
        ntb->last_ts = ticks;

        /* Mask all the interrupts, including hardware interrupt */
        intel_ntb_reg_write(8, XEON_GEN3_REG_IMINT_DISABLE, ~0ULL);

        /* Clear Interrupt Status */
        reg = intel_ntb_reg_read(8, XEON_GEN3_REG_IMINT_STATUS);
        intel_ntb_reg_write(8, XEON_GEN3_REG_IMINT_STATUS, reg);

        num_vectors = desired_vectors = MIN(pci_msix_count(ntb->device),
            XEON_GEN3_DB_MSIX_VECTOR_COUNT);

        rc = pci_alloc_msix(ntb->device, &num_vectors);
        if (rc != 0) {
                device_printf(ntb->device,
                    "Interrupt allocation failed %d\n", rc);
                return (rc);
        }
        if (desired_vectors != num_vectors) {
                device_printf(ntb->device, "Couldn't get %d vectors\n",
                    XEON_GEN3_DB_MSIX_VECTOR_COUNT);
                return (ENXIO);
        }
        /* 32 db + 1 hardware */
        if (num_vectors == XEON_GEN3_DB_MSIX_VECTOR_COUNT) {
                /* Program INTVECXX source register */
                for (i = 0; i < XEON_GEN3_DB_MSIX_VECTOR_COUNT; i++) {
                        /* interrupt source i for vector i */
                        intel_ntb_reg_write(1, XEON_GEN3_REG_IMINTVEC00 + i, i);
                        if (i == (XEON_GEN3_DB_MSIX_VECTOR_COUNT - 1)) {
                                intel_ntb_reg_write(1,
                                    XEON_GEN3_REG_IMINTVEC00 + i,
                                    XEON_GEN3_LINK_VECTOR_INDEX);
                        }
                }

                intel_ntb_create_msix_vec(ntb, num_vectors);
                rc = intel_ntb_setup_msix(ntb, num_vectors);

                /* enable all interrupts */
                intel_ntb_reg_write(8, XEON_GEN3_REG_IMINT_DISABLE, 0ULL);
        } else {
                device_printf(ntb->device, "need to remap interrupts, giving up.\n");
                return (ENXIO);
        }

        return (rc);
}

static int
intel_ntb_xeon_gen4_init_isr(struct ntb_softc *ntb)
{
        uint64_t i, reg;
        uint32_t desired_vectors, num_vectors;
        int rc;

        ntb->allocated_interrupts = 0;
        ntb->last_ts = ticks;

        /* Mask all the interrupts, including hardware interrupt */
        intel_ntb_reg_write(8, XEON_GEN4_REG_IMINT_DISABLE, ~0ULL);

        /* Clear Interrupt Status */
        reg = intel_ntb_reg_read(8, XEON_GEN4_REG_IMINT_STATUS);
        intel_ntb_reg_write(8, XEON_GEN4_REG_IMINT_STATUS, reg);

        num_vectors = desired_vectors = MIN(pci_msix_count(ntb->device),
            XEON_GEN4_DB_MSIX_VECTOR_COUNT);

        rc = pci_alloc_msix(ntb->device, &num_vectors);
        if (rc != 0) {
                device_printf(ntb->device,
                    "Interrupt allocation failed %d\n", rc);
                return (rc);
        }
        if (desired_vectors != num_vectors) {
                device_printf(ntb->device, "Couldn't get %d vectors\n",
                    XEON_GEN4_DB_MSIX_VECTOR_COUNT);
                return (ENXIO);
        }
        if (num_vectors != XEON_GEN4_DB_MSIX_VECTOR_COUNT) {
                device_printf(ntb->device,
                    "Need to remap interrupts, giving up\n");
                return (ENXIO);
        }

        /*
         * The MSIX vectors and the interrupt status bits are not lined up
         * on Gen3 (Skylake) and Gen4. By default the link status bit is bit
         * 32, however it is by default MSIX vector0. We need to fixup to
         * line them up. The vectors at reset is 1-32,0. We need to reprogram
         * to 0-32.
         */
        for (i = 0; i < XEON_GEN4_DB_MSIX_VECTOR_COUNT; i++)
                intel_ntb_reg_write(1, XEON_GEN4_REG_INTVEC + i, i);

        intel_ntb_create_msix_vec(ntb, num_vectors);
        rc = intel_ntb_setup_msix(ntb, num_vectors);

        /* enable all interrupts */
        intel_ntb_reg_write(8, XEON_GEN4_REG_IMINT_DISABLE, 0ULL);

        return (rc);
}

static int
intel_ntb_init_isr(struct ntb_softc *ntb)
{
        uint32_t desired_vectors, num_vectors;
        int rc;

        ntb->allocated_interrupts = 0;
        ntb->last_ts = ticks;

        /*
         * Mask all doorbell interrupts.  (Except link events!)
         */
        DB_MASK_LOCK(ntb);
        ntb->db_mask = ntb->db_valid_mask;
        db_iowrite(ntb, ntb->self_reg->db_mask, ntb->db_mask);
        DB_MASK_UNLOCK(ntb);

        num_vectors = desired_vectors = MIN(pci_msix_count(ntb->device),
            ntb->db_count);
        if (desired_vectors >= 1) {
                rc = pci_alloc_msix(ntb->device, &num_vectors);

                if (ntb_force_remap_mode != 0 && rc == 0 &&
                    num_vectors == desired_vectors)
                        num_vectors--;

                if (rc == 0 && num_vectors < desired_vectors) {
                        rc = intel_ntb_remap_msix(ntb->device, desired_vectors,
                            num_vectors);
                        if (rc == 0)
                                num_vectors = desired_vectors;
                        else
                                pci_release_msi(ntb->device);
                }
                if (rc != 0)
                        num_vectors = 1;
        } else
                num_vectors = 1;

        if (ntb->type == NTB_XEON_GEN1 && num_vectors < ntb->db_vec_count) {
                if (HAS_FEATURE(ntb, NTB_SB01BASE_LOCKUP)) {
                        device_printf(ntb->device,
                            "Errata workaround does not support MSI or INTX\n");
                        return (EINVAL);
                }

                ntb->db_vec_count = 1;
                ntb->db_vec_shift = XEON_DB_TOTAL_SHIFT;
                rc = intel_ntb_setup_legacy_interrupt(ntb);
        } else {
                if (num_vectors - 1 != XEON_NONLINK_DB_MSIX_BITS &&
                    HAS_FEATURE(ntb, NTB_SB01BASE_LOCKUP)) {
                        device_printf(ntb->device,
                            "Errata workaround expects %d doorbell bits\n",
                            XEON_NONLINK_DB_MSIX_BITS);
                        return (EINVAL);
                }

                intel_ntb_create_msix_vec(ntb, num_vectors);
                rc = intel_ntb_setup_msix(ntb, num_vectors);
        }
        if (rc != 0) {
                device_printf(ntb->device,
                    "Error allocating interrupts: %d\n", rc);
                intel_ntb_free_msix_vec(ntb);
        }

        return (rc);
}

static int
intel_ntb_setup_legacy_interrupt(struct ntb_softc *ntb)
{
        int rc;

        ntb->int_info[0].rid = 0;
        ntb->int_info[0].res = bus_alloc_resource_any(ntb->device, SYS_RES_IRQ,
            &ntb->int_info[0].rid, RF_SHAREABLE|RF_ACTIVE);
        if (ntb->int_info[0].res == NULL) {
                device_printf(ntb->device, "bus_alloc_resource failed\n");
                return (ENOMEM);
        }

        ntb->int_info[0].tag = NULL;
        ntb->allocated_interrupts = 1;

        rc = bus_setup_intr(ntb->device, ntb->int_info[0].res,
            INTR_MPSAFE | INTR_TYPE_MISC, NULL, ndev_irq_isr,
            ntb, &ntb->int_info[0].tag);
        if (rc != 0) {
                device_printf(ntb->device, "bus_setup_intr failed\n");
                return (ENXIO);
        }

        return (0);
}

static void
intel_ntb_teardown_interrupts(struct ntb_softc *ntb)
{
        struct ntb_int_info *current_int;
        int i;

        for (i = 0; i < ntb->allocated_interrupts; i++) {
                current_int = &ntb->int_info[i];
                if (current_int->tag != NULL)
                        bus_teardown_intr(ntb->device, current_int->res,
                            current_int->tag);

                if (current_int->res != NULL)
                        bus_release_resource(ntb->device, SYS_RES_IRQ,
                            rman_get_rid(current_int->res), current_int->res);
        }

        intel_ntb_free_msix_vec(ntb);
        pci_release_msi(ntb->device);
}

static inline uint64_t
db_ioread(struct ntb_softc *ntb, uint64_t regoff)
{

        switch (ntb->type) {
        case NTB_ATOM:
        case NTB_XEON_GEN3:
        case NTB_XEON_GEN4:
                return (intel_ntb_reg_read(8, regoff));
        case NTB_XEON_GEN1:
                return (intel_ntb_reg_read(2, regoff));
        }
        __assert_unreachable();
}

static inline void
db_iowrite(struct ntb_softc *ntb, uint64_t regoff, uint64_t val)
{

        KASSERT((val & ~ntb->db_valid_mask) == 0,
            ("%s: Invalid bits 0x%jx (valid: 0x%jx)", __func__,
             (uintmax_t)(val & ~ntb->db_valid_mask),
             (uintmax_t)ntb->db_valid_mask));

        if (regoff == ntb->self_reg->db_mask)
                DB_MASK_ASSERT(ntb, MA_OWNED);
        db_iowrite_raw(ntb, regoff, val);
}

static inline void
db_iowrite_raw(struct ntb_softc *ntb, uint64_t regoff, uint64_t val)
{

        switch (ntb->type) {
        case NTB_ATOM:
        case NTB_XEON_GEN3:
        case NTB_XEON_GEN4:
                intel_ntb_reg_write(8, regoff, val);
                break;
        case NTB_XEON_GEN1:
                intel_ntb_reg_write(2, regoff, (uint16_t)val);
                break;
        }
}

static void
intel_ntb_db_set_mask(device_t dev, uint64_t bits)
{
        struct ntb_softc *ntb = device_get_softc(dev);

        DB_MASK_LOCK(ntb);
        ntb->db_mask |= bits;
        if (!HAS_FEATURE(ntb, NTB_SB01BASE_LOCKUP))
                db_iowrite(ntb, ntb->self_reg->db_mask, ntb->db_mask);
        DB_MASK_UNLOCK(ntb);
}

static void
intel_ntb_db_clear_mask(device_t dev, uint64_t bits)
{
        struct ntb_softc *ntb = device_get_softc(dev);
        uint64_t ibits;
        int i;

        KASSERT((bits & ~ntb->db_valid_mask) == 0,
            ("%s: Invalid bits 0x%jx (valid: 0x%jx)", __func__,
             (uintmax_t)(bits & ~ntb->db_valid_mask),
             (uintmax_t)ntb->db_valid_mask));

        DB_MASK_LOCK(ntb);
        ibits = ntb->fake_db & ntb->db_mask & bits;
        ntb->db_mask &= ~bits;
        if (HAS_FEATURE(ntb, NTB_SB01BASE_LOCKUP)) {
                /* Simulate fake interrupts if unmasked DB bits are set. */
                ntb->force_db |= ibits;
                for (i = 0; i < XEON_NONLINK_DB_MSIX_BITS; i++) {
                        if ((ibits & intel_ntb_db_vector_mask(dev, i)) != 0)
                                swi_sched(ntb->int_info[i].tag, 0);
                }
        } else {
                db_iowrite(ntb, ntb->self_reg->db_mask, ntb->db_mask);
        }
        DB_MASK_UNLOCK(ntb);
}

static uint64_t
intel_ntb_db_read(device_t dev)
{
        struct ntb_softc *ntb = device_get_softc(dev);

        if (HAS_FEATURE(ntb, NTB_SB01BASE_LOCKUP))
                return (ntb->fake_db);
        if (ntb->type == NTB_XEON_GEN3)
                return (intel_ntb_reg_read(8, XEON_GEN3_REG_IMINT_STATUS));
        else
                return (db_ioread(ntb, ntb->self_reg->db_bell));
}

static void
intel_ntb_db_clear(device_t dev, uint64_t bits)
{
        struct ntb_softc *ntb = device_get_softc(dev);

        KASSERT((bits & ~ntb->db_valid_mask) == 0,
            ("%s: Invalid bits 0x%jx (valid: 0x%jx)", __func__,
             (uintmax_t)(bits & ~ntb->db_valid_mask),
             (uintmax_t)ntb->db_valid_mask));

        if (HAS_FEATURE(ntb, NTB_SB01BASE_LOCKUP)) {
                DB_MASK_LOCK(ntb);
                ntb->fake_db &= ~bits;
                DB_MASK_UNLOCK(ntb);
                return;
        }

        if (ntb->type == NTB_XEON_GEN3)
                intel_ntb_reg_write(4, XEON_GEN3_REG_IMINT_STATUS,
                    (uint32_t)bits);
        else
                db_iowrite(ntb, ntb->self_reg->db_bell, bits);
}

static inline uint64_t
intel_ntb_vec_mask(struct ntb_softc *ntb, uint64_t db_vector)
{
        uint64_t shift, mask;

        if (HAS_FEATURE(ntb, NTB_SB01BASE_LOCKUP)) {
                /*
                 * Remap vectors in custom way to make at least first
                 * three doorbells to not generate stray events.
                 * This breaks Linux compatibility (if one existed)
                 * when more then one DB is used (not by if_ntb).
                 */
                if (db_vector < XEON_NONLINK_DB_MSIX_BITS - 1)
                        return (1 << db_vector);
                if (db_vector == XEON_NONLINK_DB_MSIX_BITS - 1)
                        return (0x7ffc);
        }

        shift = ntb->db_vec_shift;
        mask = (1ull << shift) - 1;
        return (mask << (shift * db_vector));
}

static void
intel_ntb_interrupt(struct ntb_softc *ntb, uint32_t vec)
{
        uint64_t vec_mask;

        ntb->last_ts = ticks;
        vec_mask = intel_ntb_vec_mask(ntb, vec);

        if ((ntb->type == NTB_XEON_GEN3 || ntb->type == NTB_XEON_GEN4) &&
            vec == XEON_GEN3_LINK_VECTOR_INDEX)
                vec_mask |= ntb->db_link_mask;
        if ((vec_mask & ntb->db_link_mask) != 0) {
                if (intel_ntb_poll_link(ntb))
                        ntb_link_event(ntb->device);
                if (ntb->type == NTB_XEON_GEN3)
                        intel_ntb_reg_write(8, XEON_GEN3_REG_IMINT_STATUS,
                            intel_ntb_reg_read(8, XEON_GEN3_REG_IMINT_STATUS));
                if (ntb->type == NTB_XEON_GEN4)
                        intel_ntb_reg_write(8, XEON_GEN4_REG_IMINT_STATUS,
                            intel_ntb_reg_read(8, XEON_GEN4_REG_IMINT_STATUS));
        }

        if (HAS_FEATURE(ntb, NTB_SB01BASE_LOCKUP) &&
            (vec_mask & ntb->db_link_mask) == 0) {
                DB_MASK_LOCK(ntb);

                /*
                 * Do not report same DB events again if not cleared yet,
                 * unless the mask was just cleared for them and this
                 * interrupt handler call can be the consequence of it.
                 */
                vec_mask &= ~ntb->fake_db | ntb->force_db;
                ntb->force_db &= ~vec_mask;

                /* Update our internal doorbell register. */
                ntb->fake_db |= vec_mask;

                /* Do not report masked DB events. */
                vec_mask &= ~ntb->db_mask;

                DB_MASK_UNLOCK(ntb);
        }

        if ((vec_mask & ntb->db_valid_mask) != 0)
                ntb_db_event(ntb->device, vec);
}

static void
ndev_vec_isr(void *arg)
{
        struct ntb_vec *nvec = arg;

        intel_ntb_interrupt(nvec->ntb, nvec->num);
}

static void
ndev_irq_isr(void *arg)
{
        /* If we couldn't set up MSI-X, we only have the one vector. */
        intel_ntb_interrupt(arg, 0);
}

static int
intel_ntb_create_msix_vec(struct ntb_softc *ntb, uint32_t num_vectors)
{
        uint32_t i;

        ntb->msix_vec = malloc(num_vectors * sizeof(*ntb->msix_vec), M_NTB,
            M_ZERO | M_WAITOK);
        for (i = 0; i < num_vectors; i++) {
                ntb->msix_vec[i].num = i;
                ntb->msix_vec[i].ntb = ntb;
        }

        return (0);
}

static void
intel_ntb_free_msix_vec(struct ntb_softc *ntb)
{

        if (ntb->msix_vec == NULL)
                return;

        free(ntb->msix_vec, M_NTB);
        ntb->msix_vec = NULL;
}

static void
intel_ntb_get_msix_info(struct ntb_softc *ntb)
{
        struct pci_devinfo *dinfo;
        struct pcicfg_msix *msix;
        uint32_t laddr, data, i, offset;

        dinfo = device_get_ivars(ntb->device);
        msix = &dinfo->cfg.msix;

        CTASSERT(XEON_NONLINK_DB_MSIX_BITS == nitems(ntb->msix_data));

        for (i = 0; i < XEON_NONLINK_DB_MSIX_BITS; i++) {
                offset = msix->msix_table_offset + i * PCI_MSIX_ENTRY_SIZE;

                laddr = bus_read_4(msix->msix_table_res, offset +
                    PCI_MSIX_ENTRY_LOWER_ADDR);
                intel_ntb_printf(2, "local MSIX addr(%u): 0x%x\n", i, laddr);

                KASSERT((laddr & MSI_INTEL_ADDR_BASE) == MSI_INTEL_ADDR_BASE,
                    ("local MSIX addr 0x%x not in MSI base 0x%x", laddr,
                     MSI_INTEL_ADDR_BASE));
                ntb->msix_data[i].nmd_ofs = laddr;

                data = bus_read_4(msix->msix_table_res, offset +
                    PCI_MSIX_ENTRY_DATA);
                intel_ntb_printf(2, "local MSIX data(%u): 0x%x\n", i, data);

                ntb->msix_data[i].nmd_data = data;
        }
}

static struct ntb_hw_info *
intel_ntb_get_device_info(uint32_t device_id)
{
        struct ntb_hw_info *ep;

        for (ep = pci_ids; ep < &pci_ids[nitems(pci_ids)]; ep++) {
                if (ep->device_id == device_id)
                        return (ep);
        }
        return (NULL);
}

static void
intel_ntb_teardown_xeon(struct ntb_softc *ntb)
{

        if (ntb->reg != NULL)
                intel_ntb_link_disable(ntb->device);
}

static void
intel_ntb_detect_max_mw(struct ntb_softc *ntb)
{

        switch (ntb->type) {
        case NTB_ATOM:
                ntb->mw_count = ATOM_MW_COUNT;
                break;
        case NTB_XEON_GEN1:
                if (HAS_FEATURE(ntb, NTB_SPLIT_BAR))
                        ntb->mw_count = XEON_HSX_SPLIT_MW_COUNT;
                else
                        ntb->mw_count = XEON_SNB_MW_COUNT;
                break;
        case NTB_XEON_GEN3:
        case NTB_XEON_GEN4:
                if (HAS_FEATURE(ntb, NTB_SPLIT_BAR))
                        ntb->mw_count = XEON_GEN3_SPLIT_MW_COUNT;
                else
                        ntb->mw_count = XEON_GEN3_MW_COUNT;
                break;
        }
}

static int
intel_ntb_detect_xeon(struct ntb_softc *ntb)
{
        uint8_t ppd, conn_type;

        ppd = pci_read_config(ntb->device, NTB_PPD_OFFSET, 1);
        ntb->ppd = ppd;

        if ((ppd & XEON_PPD_DEV_TYPE) != 0)
                ntb->dev_type = NTB_DEV_DSD;
        else
                ntb->dev_type = NTB_DEV_USD;

        if ((ppd & XEON_PPD_SPLIT_BAR) != 0)
                ntb->features |= NTB_SPLIT_BAR;

        if (HAS_FEATURE(ntb, NTB_SB01BASE_LOCKUP) &&
            !HAS_FEATURE(ntb, NTB_SPLIT_BAR)) {
                device_printf(ntb->device,
                    "Can not apply SB01BASE_LOCKUP workaround "
                    "with split BARs disabled!\n");
                device_printf(ntb->device,
                    "Expect system hangs under heavy NTB traffic!\n");
                ntb->features &= ~NTB_SB01BASE_LOCKUP;
        }

        /*
         * SDOORBELL errata workaround gets in the way of SB01BASE_LOCKUP
         * errata workaround; only do one at a time.
         */
        if (HAS_FEATURE(ntb, NTB_SB01BASE_LOCKUP))
                ntb->features &= ~NTB_SDOORBELL_LOCKUP;

        conn_type = ppd & XEON_PPD_CONN_TYPE;
        switch (conn_type) {
        case NTB_CONN_B2B:
                ntb->conn_type = conn_type;
                break;
        case NTB_CONN_RP:
        case NTB_CONN_TRANSPARENT:
        default:
                device_printf(ntb->device, "Unsupported connection type: %u\n",
                    (unsigned)conn_type);
                return (ENXIO);
        }
        return (0);
}

static int
intel_ntb_detect_atom(struct ntb_softc *ntb)
{
        uint32_t ppd, conn_type;

        ppd = pci_read_config(ntb->device, NTB_PPD_OFFSET, 4);
        ntb->ppd = ppd;

        if ((ppd & ATOM_PPD_DEV_TYPE) != 0)
                ntb->dev_type = NTB_DEV_DSD;
        else
                ntb->dev_type = NTB_DEV_USD;

        conn_type = (ppd & ATOM_PPD_CONN_TYPE) >> 8;
        switch (conn_type) {
        case NTB_CONN_B2B:
                ntb->conn_type = conn_type;
                break;
        default:
                device_printf(ntb->device, "Unsupported NTB configuration\n");
                return (ENXIO);
        }
        return (0);
}

static int
intel_ntb_detect_xeon_gen3(struct ntb_softc *ntb)
{
        uint8_t ppd, conn_type;

        ppd = pci_read_config(ntb->device, XEON_GEN3_INT_REG_PPD, 1);
        ntb->ppd = ppd;

        /* check port definition */
        conn_type = XEON_GEN3_REG_PPD_PORT_DEF_F(ppd);
        switch (conn_type) {
        case NTB_CONN_B2B:
                ntb->conn_type = conn_type;
                break;
        default:
                device_printf(ntb->device, "Unsupported connection type: %u\n",
                    conn_type);
                return (ENXIO);
        }

        /* check cross link configuration status */
        if (XEON_GEN3_REG_PPD_CONF_STS_F(ppd)) {
                /* NTB Port is configured as DSD/USP */
                ntb->dev_type = NTB_DEV_DSD;
        } else {
                /* NTB Port is configured as USD/DSP */
                ntb->dev_type = NTB_DEV_USD;
        }

        if (XEON_GEN3_REG_PPD_ONE_MSIX_F(ppd)) {
                /*
                 * This bit when set, causes only a single MSI-X message to be
                 * generated if MSI-X is enabled.
                 */
                ntb->features |= NTB_ONE_MSIX;
        }

        if (XEON_GEN3_REG_PPD_BAR45_SPL_F(ppd)) {
                /* BARs 4 and 5 are presented as two 32b non-prefetchable BARs */
                ntb->features |= NTB_SPLIT_BAR;
        }

        device_printf(ntb->device, "conn type 0x%02x, dev type 0x%02x,"
            "features 0x%02x\n", ntb->conn_type, ntb->dev_type, ntb->features);

        return (0);
}

static int
intel_ntb_is_ICX(struct ntb_softc *ntb)
{
        uint8_t revision;

        revision = pci_get_revid(ntb->device);
        if (ntb->type == NTB_XEON_GEN4 &&
            revision >= PCI_DEV_REV_ICX_MIN &&
            revision <= PCI_DEV_REV_ICX_MAX)
                return (1);

        return (0);
}

static int
intel_ntb_is_SPR(struct ntb_softc *ntb)
{
        uint8_t revision;

        revision = pci_get_revid(ntb->device);
        if (ntb->type == NTB_XEON_GEN4 &&
            revision > PCI_DEV_REV_ICX_MAX)
                return (1);

        return (0);
}

static int
intel_ntb_detect_xeon_gen4(struct ntb_softc *ntb)
{
        if (intel_ntb_is_ICX(ntb)) {
                ntb->features |= NTB_BAR_ALIGN;
                ntb->features |= NTB_LTR_BAD;
        }
        return (0);
}

static int
intel_ntb_detect_xeon_gen4_cfg(struct ntb_softc *ntb)
{
        uint32_t ppd1;

        ppd1 = intel_ntb_reg_read(4, XEON_GEN4_REG_PPD1);
        ntb->ppd = ppd1;
        if (intel_ntb_is_ICX(ntb)) {
                if ((ppd1 & GEN4_PPD_TOPO_MASK) == GEN4_PPD_TOPO_B2B_USD) {
                        /* NTB Port is configured as USD/DSP */
                        ntb->conn_type = NTB_CONN_B2B;
                        ntb->dev_type = NTB_DEV_USD;
                } else if ((ppd1 & GEN4_PPD_TOPO_MASK) == GEN4_PPD_TOPO_B2B_DSD) {
                        /* NTB Port is configured as DSD/USP */
                        ntb->conn_type = NTB_CONN_B2B;
                        ntb->dev_type = NTB_DEV_DSD;
                } else {
                        device_printf(ntb->device, "Unsupported connection type: %u\n",
                            (ppd1 & GEN4_PPD_CONN_MASK));
                        return (ENXIO);
                }
        } else if (intel_ntb_is_SPR(ntb)) {
                if ((ppd1 & SPR_PPD_TOPO_MASK) == SPR_PPD_TOPO_B2B_USD) {
                        /* NTB Port is configured as USD/DSP */
                        ntb->conn_type = NTB_CONN_B2B;
                        ntb->dev_type = NTB_DEV_USD;
                } else if ((ppd1 & SPR_PPD_TOPO_MASK) == SPR_PPD_TOPO_B2B_DSD) {
                        /* NTB Port is configured as DSD/USP */
                        ntb->conn_type = NTB_CONN_B2B;
                        ntb->dev_type = NTB_DEV_DSD;
                } else {
                        device_printf(ntb->device, "Unsupported connection type: %u\n",
                            (ppd1 & SPR_PPD_CONN_MASK));
                        return (ENXIO);
                }
        }

        device_printf(ntb->device, "conn type 0x%02x, dev type 0x%02x,"
            "features 0x%02x\n", ntb->conn_type, ntb->dev_type, ntb->features);

        return (0);
}

static int
intel_ntb_xeon_init_dev(struct ntb_softc *ntb)
{
        int rc;

        ntb->spad_count         = XEON_SPAD_COUNT;
        ntb->db_count           = XEON_DB_COUNT;
        ntb->db_link_mask       = XEON_DB_LINK_BIT;
        ntb->db_vec_count       = XEON_DB_MSIX_VECTOR_COUNT;
        ntb->db_vec_shift       = XEON_DB_MSIX_VECTOR_SHIFT;

        if (ntb->conn_type != NTB_CONN_B2B) {
                device_printf(ntb->device, "Connection type %d not supported\n",
                    ntb->conn_type);
                return (ENXIO);
        }

        ntb->reg = &xeon_reg;
        ntb->self_reg = &xeon_pri_reg;
        ntb->peer_reg = &xeon_b2b_reg;
        ntb->xlat_reg = &xeon_sec_xlat;

        if (HAS_FEATURE(ntb, NTB_SB01BASE_LOCKUP)) {
                ntb->force_db = ntb->fake_db = 0;
                ntb->msix_mw_idx = (ntb->mw_count + g_ntb_msix_idx) %
                    ntb->mw_count;
                intel_ntb_printf(2, "Setting up MSIX mw idx %d means %u\n",
                    g_ntb_msix_idx, ntb->msix_mw_idx);
                rc = intel_ntb_mw_set_wc_internal(ntb, ntb->msix_mw_idx,
                    VM_MEMATTR_UNCACHEABLE);
                KASSERT(rc == 0, ("shouldn't fail"));
        } else if (HAS_FEATURE(ntb, NTB_SDOORBELL_LOCKUP)) {
                /*
                 * There is a Xeon hardware errata related to writes to SDOORBELL or
                 * B2BDOORBELL in conjunction with inbound access to NTB MMIO space,
                 * which may hang the system.  To workaround this, use a memory
                 * window to access the interrupt and scratch pad registers on the
                 * remote system.
                 */
                ntb->b2b_mw_idx = (ntb->mw_count + g_ntb_mw_idx) %
                    ntb->mw_count;
                intel_ntb_printf(2, "Setting up b2b mw idx %d means %u\n",
                    g_ntb_mw_idx, ntb->b2b_mw_idx);
                rc = intel_ntb_mw_set_wc_internal(ntb, ntb->b2b_mw_idx,
                    VM_MEMATTR_UNCACHEABLE);
                KASSERT(rc == 0, ("shouldn't fail"));
        } else if (HAS_FEATURE(ntb, NTB_B2BDOORBELL_BIT14))
                /*
                 * HW Errata on bit 14 of b2bdoorbell register.  Writes will not be
                 * mirrored to the remote system.  Shrink the number of bits by one,
                 * since bit 14 is the last bit.
                 *
                 * On REGS_THRU_MW errata mode, we don't use the b2bdoorbell register
                 * anyway.  Nor for non-B2B connection types.
                 */
                ntb->db_count = XEON_DB_COUNT - 1;

        ntb->db_valid_mask = (1ull << ntb->db_count) - 1;

        if (ntb->dev_type == NTB_DEV_USD)
                rc = xeon_setup_b2b_mw(ntb, &xeon_b2b_dsd_addr,
                    &xeon_b2b_usd_addr);
        else
                rc = xeon_setup_b2b_mw(ntb, &xeon_b2b_usd_addr,
                    &xeon_b2b_dsd_addr);
        if (rc != 0)
                return (rc);

        /* Enable Bus Master and Memory Space on the secondary side */
        intel_ntb_reg_write(2, XEON_SPCICMD_OFFSET,
            PCIM_CMD_MEMEN | PCIM_CMD_BUSMASTEREN);

        /*
         * Mask all doorbell interrupts.
         */
        DB_MASK_LOCK(ntb);
        ntb->db_mask = ntb->db_valid_mask;
        db_iowrite(ntb, ntb->self_reg->db_mask, ntb->db_mask);
        DB_MASK_UNLOCK(ntb);

        rc = intel_ntb_init_isr(ntb);
        return (rc);
}

static int
intel_ntb_xeon_gen3_init_dev(struct ntb_softc *ntb)
{
        int rc;

        ntb->spad_count = XEON_GEN3_SPAD_COUNT;
        ntb->db_count = XEON_GEN3_DB_COUNT;
        ntb->db_link_mask = XEON_GEN3_DB_LINK_BIT;
        ntb->db_vec_count = XEON_GEN3_DB_MSIX_VECTOR_COUNT;
        ntb->db_vec_shift = XEON_GEN3_DB_MSIX_VECTOR_SHIFT;

        if (ntb->conn_type != NTB_CONN_B2B) {
                device_printf(ntb->device, "Connection type %d not supported\n",
                    ntb->conn_type);
                return (ENXIO);
        }

        ntb->reg = &xeon_gen3_reg;
        ntb->self_reg = &xeon_gen3_pri_reg;
        ntb->peer_reg = &xeon_gen3_b2b_reg;
        ntb->xlat_reg = &xeon_gen3_sec_xlat;

        ntb->db_valid_mask = (1ULL << ntb->db_count) - 1;

        xeon_gen3_setup_b2b_mw(ntb);

        /* Enable Bus Master and Memory Space on the External Side */
        intel_ntb_reg_write(2, XEON_GEN3_EXT_REG_PCI_CMD,
            PCIM_CMD_MEMEN | PCIM_CMD_BUSMASTEREN);

        /* Setup Interrupt */
        rc = intel_ntb_xeon_gen3_init_isr(ntb);

        return (rc);
}

static int
intel_ntb_xeon_gen4_init_dev(struct ntb_softc *ntb)
{
        int rc;
        uint16_t lnkctl;

        ntb->spad_count = XEON_GEN4_SPAD_COUNT;
        ntb->db_count = XEON_GEN4_DB_COUNT;
        ntb->db_link_mask = XEON_GEN4_DB_LINK_BIT;
        ntb->db_vec_count = XEON_GEN4_DB_MSIX_VECTOR_COUNT;
        ntb->db_vec_shift = XEON_GEN4_DB_MSIX_VECTOR_SHIFT;

        if (intel_ntb_detect_xeon_gen4_cfg(ntb) != 0)
                return (ENXIO);

        ntb->reg = &xeon_gen4_reg;
        ntb->self_reg = &xeon_gen4_pri_reg;
        ntb->peer_reg = &xeon_gen4_b2b_reg;
        ntb->xlat_reg = &xeon_gen4_sec_xlat;

        ntb->db_valid_mask = (1ULL << ntb->db_count) - 1;
        xeon_gen4_setup_b2b_mw(ntb);

        /* init link setup */
        lnkctl = intel_ntb_reg_read(2, XEON_GEN4_REG_LINK_CTRL);
        lnkctl |= GEN4_LINK_CTRL_LINK_DISABLE;
        intel_ntb_reg_write(2, XEON_GEN4_REG_LINK_CTRL, lnkctl);

        /* Setup Interrupt */
        rc = intel_ntb_xeon_gen4_init_isr(ntb);
        return (rc);
}

static int
intel_ntb_atom_init_dev(struct ntb_softc *ntb)
{
        int error;

        KASSERT(ntb->conn_type == NTB_CONN_B2B,
            ("Unsupported NTB configuration (%d)\n", ntb->conn_type));

        ntb->spad_count          = ATOM_SPAD_COUNT;
        ntb->db_count            = ATOM_DB_COUNT;
        ntb->db_vec_count        = ATOM_DB_MSIX_VECTOR_COUNT;
        ntb->db_vec_shift        = ATOM_DB_MSIX_VECTOR_SHIFT;
        ntb->db_valid_mask       = (1ull << ntb->db_count) - 1;

        ntb->reg = &atom_reg;
        ntb->self_reg = &atom_pri_reg;
        ntb->peer_reg = &atom_b2b_reg;
        ntb->xlat_reg = &atom_sec_xlat;

        /*
         * FIXME - MSI-X bug on early Atom HW, remove once internal issue is
         * resolved.  Mask transaction layer internal parity errors.
         */
        pci_write_config(ntb->device, 0xFC, 0x4, 4);

        configure_atom_secondary_side_bars(ntb);

        /* Enable Bus Master and Memory Space on the secondary side */
        intel_ntb_reg_write(2, ATOM_SPCICMD_OFFSET,
            PCIM_CMD_MEMEN | PCIM_CMD_BUSMASTEREN);

        error = intel_ntb_init_isr(ntb);
        if (error != 0)
                return (error);

        /* Initiate PCI-E link training */
        intel_ntb_link_enable(ntb->device, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);

        callout_reset(&ntb->heartbeat_timer, 0, atom_link_hb, ntb);

        return (0);
}

/* XXX: Linux driver doesn't seem to do any of this for Atom. */
static void
configure_atom_secondary_side_bars(struct ntb_softc *ntb)
{

        if (ntb->dev_type == NTB_DEV_USD) {
                intel_ntb_reg_write(8, ATOM_PBAR2XLAT_OFFSET,
                    XEON_B2B_BAR2_ADDR64);
                intel_ntb_reg_write(8, ATOM_PBAR4XLAT_OFFSET,
                    XEON_B2B_BAR4_ADDR64);
                intel_ntb_reg_write(8, ATOM_MBAR23_OFFSET, XEON_B2B_BAR2_ADDR64);
                intel_ntb_reg_write(8, ATOM_MBAR45_OFFSET, XEON_B2B_BAR4_ADDR64);
        } else {
                intel_ntb_reg_write(8, ATOM_PBAR2XLAT_OFFSET,
                    XEON_B2B_BAR2_ADDR64);
                intel_ntb_reg_write(8, ATOM_PBAR4XLAT_OFFSET,
                    XEON_B2B_BAR4_ADDR64);
                intel_ntb_reg_write(8, ATOM_MBAR23_OFFSET, XEON_B2B_BAR2_ADDR64);
                intel_ntb_reg_write(8, ATOM_MBAR45_OFFSET, XEON_B2B_BAR4_ADDR64);
        }
}

/*
 * When working around Xeon SDOORBELL errata by remapping remote registers in a
 * MW, limit the B2B MW to half a MW.  By sharing a MW, half the shared MW
 * remains for use by a higher layer.
 *
 * Will only be used if working around SDOORBELL errata and the BIOS-configured
 * MW size is sufficiently large.
 */
static unsigned int ntb_b2b_mw_share;
SYSCTL_UINT(_hw_ntb, OID_AUTO, b2b_mw_share, CTLFLAG_RDTUN, &ntb_b2b_mw_share,
    0, "If enabled (non-zero), prefer to share half of the B2B peer register "
    "MW with higher level consumers.  Both sides of the NTB MUST set the same "
    "value here.");

static void
xeon_reset_sbar_size(struct ntb_softc *ntb, enum ntb_bar idx,
    enum ntb_bar regbar)
{
        struct ntb_pci_bar_info *bar;
        uint8_t bar_sz;

        if (!HAS_FEATURE(ntb, NTB_SPLIT_BAR) && idx >= NTB_B2B_BAR_3)
                return;

        bar = &ntb->bar_info[idx];
        bar_sz = pci_read_config(ntb->device, bar->psz_off, 1);
        if (idx == regbar) {
                if (ntb->b2b_off != 0)
                        bar_sz--;
                else
                        bar_sz = 0;
        }
        pci_write_config(ntb->device, bar->ssz_off, bar_sz, 1);
        bar_sz = pci_read_config(ntb->device, bar->ssz_off, 1);
        (void)bar_sz;
}

static void
xeon_set_sbar_base_and_limit(struct ntb_softc *ntb, uint64_t bar_addr,
    enum ntb_bar idx, enum ntb_bar regbar)
{
        uint64_t reg_val;
        uint32_t base_reg, lmt_reg;

        bar_get_xlat_params(ntb, idx, &base_reg, NULL, &lmt_reg);
        if (idx == regbar) {
                if (ntb->b2b_off)
                        bar_addr += ntb->b2b_off;
                else
                        bar_addr = 0;
        }

        if (!bar_is_64bit(ntb, idx)) {
                intel_ntb_reg_write(4, base_reg, bar_addr);
                reg_val = intel_ntb_reg_read(4, base_reg);
                (void)reg_val;

                intel_ntb_reg_write(4, lmt_reg, bar_addr);
                reg_val = intel_ntb_reg_read(4, lmt_reg);
                (void)reg_val;
        } else {
                intel_ntb_reg_write(8, base_reg, bar_addr);
                reg_val = intel_ntb_reg_read(8, base_reg);
                (void)reg_val;

                intel_ntb_reg_write(8, lmt_reg, bar_addr);
                reg_val = intel_ntb_reg_read(8, lmt_reg);
                (void)reg_val;
        }
}

static void
xeon_set_pbar_xlat(struct ntb_softc *ntb, uint64_t base_addr, enum ntb_bar idx)
{
        struct ntb_pci_bar_info *bar;

        bar = &ntb->bar_info[idx];
        if (HAS_FEATURE(ntb, NTB_SPLIT_BAR) && idx >= NTB_B2B_BAR_2) {
                intel_ntb_reg_write(4, bar->pbarxlat_off, base_addr);
                base_addr = intel_ntb_reg_read(4, bar->pbarxlat_off);
        } else {
                intel_ntb_reg_write(8, bar->pbarxlat_off, base_addr);
                base_addr = intel_ntb_reg_read(8, bar->pbarxlat_off);
        }
        (void)base_addr;
}

static int
xeon_setup_b2b_mw(struct ntb_softc *ntb, const struct ntb_b2b_addr *addr,
    const struct ntb_b2b_addr *peer_addr)
{
        struct ntb_pci_bar_info *b2b_bar;
        vm_size_t bar_size;
        uint64_t bar_addr;
        enum ntb_bar b2b_bar_num, i;

        if (ntb->b2b_mw_idx == B2B_MW_DISABLED) {
                b2b_bar = NULL;
                b2b_bar_num = NTB_CONFIG_BAR;
                ntb->b2b_off = 0;
        } else {
                b2b_bar_num = intel_ntb_mw_to_bar(ntb, ntb->b2b_mw_idx);
                KASSERT(b2b_bar_num > 0 && b2b_bar_num < NTB_MAX_BARS,
                    ("invalid b2b mw bar"));

                b2b_bar = &ntb->bar_info[b2b_bar_num];
                bar_size = b2b_bar->size;

                if (ntb_b2b_mw_share != 0 &&
                    (bar_size >> 1) >= XEON_B2B_MIN_SIZE)
                        ntb->b2b_off = bar_size >> 1;
                else if (bar_size >= XEON_B2B_MIN_SIZE) {
                        ntb->b2b_off = 0;
                } else {
                        device_printf(ntb->device,
                            "B2B bar size is too small!\n");
                        return (EIO);
                }
        }

        /*
         * Reset the secondary bar sizes to match the primary bar sizes.
         * (Except, disable or halve the size of the B2B secondary bar.)
         */
        for (i = NTB_B2B_BAR_1; i < NTB_MAX_BARS; i++)
                xeon_reset_sbar_size(ntb, i, b2b_bar_num);

        bar_addr = 0;
        if (b2b_bar_num == NTB_CONFIG_BAR)
                bar_addr = addr->bar0_addr;
        else if (b2b_bar_num == NTB_B2B_BAR_1)
                bar_addr = addr->bar2_addr64;
        else if (b2b_bar_num == NTB_B2B_BAR_2 && !HAS_FEATURE(ntb, NTB_SPLIT_BAR))
                bar_addr = addr->bar4_addr64;
        else if (b2b_bar_num == NTB_B2B_BAR_2)
                bar_addr = addr->bar4_addr32;
        else if (b2b_bar_num == NTB_B2B_BAR_3)
                bar_addr = addr->bar5_addr32;
        else
                KASSERT(false, ("invalid bar"));

        intel_ntb_reg_write(8, XEON_SBAR0BASE_OFFSET, bar_addr);

        /*
         * Other SBARs are normally hit by the PBAR xlat, except for the b2b
         * register BAR.  The B2B BAR is either disabled above or configured
         * half-size.  It starts at PBAR xlat + offset.
         *
         * Also set up incoming BAR limits == base (zero length window).
         */
        xeon_set_sbar_base_and_limit(ntb, addr->bar2_addr64, NTB_B2B_BAR_1,
            b2b_bar_num);
        if (HAS_FEATURE(ntb, NTB_SPLIT_BAR)) {
                xeon_set_sbar_base_and_limit(ntb, addr->bar4_addr32,
                    NTB_B2B_BAR_2, b2b_bar_num);
                xeon_set_sbar_base_and_limit(ntb, addr->bar5_addr32,
                    NTB_B2B_BAR_3, b2b_bar_num);
        } else
                xeon_set_sbar_base_and_limit(ntb, addr->bar4_addr64,
                    NTB_B2B_BAR_2, b2b_bar_num);

        /* Zero incoming translation addrs */
        intel_ntb_reg_write(8, XEON_SBAR2XLAT_OFFSET, 0);
        intel_ntb_reg_write(8, XEON_SBAR4XLAT_OFFSET, 0);

        if (HAS_FEATURE(ntb, NTB_SB01BASE_LOCKUP)) {
                uint32_t xlat_reg, lmt_reg;
                enum ntb_bar bar_num;

                /*
                 * We point the chosen MSIX MW BAR xlat to remote LAPIC for
                 * workaround
                 */
                bar_num = intel_ntb_mw_to_bar(ntb, ntb->msix_mw_idx);
                bar_get_xlat_params(ntb, bar_num, NULL, &xlat_reg, &lmt_reg);
                if (bar_is_64bit(ntb, bar_num)) {
                        intel_ntb_reg_write(8, xlat_reg, MSI_INTEL_ADDR_BASE);
                        ntb->msix_xlat = intel_ntb_reg_read(8, xlat_reg);
                        intel_ntb_reg_write(8, lmt_reg, 0);
                } else {
                        intel_ntb_reg_write(4, xlat_reg, MSI_INTEL_ADDR_BASE);
                        ntb->msix_xlat = intel_ntb_reg_read(4, xlat_reg);
                        intel_ntb_reg_write(4, lmt_reg, 0);
                }

                ntb->peer_lapic_bar =  &ntb->bar_info[bar_num];
        }
        (void)intel_ntb_reg_read(8, XEON_SBAR2XLAT_OFFSET);
        (void)intel_ntb_reg_read(8, XEON_SBAR4XLAT_OFFSET);

        /* Zero outgoing translation limits (whole bar size windows) */
        intel_ntb_reg_write(8, XEON_PBAR2LMT_OFFSET, 0);
        intel_ntb_reg_write(8, XEON_PBAR4LMT_OFFSET, 0);

        /* Set outgoing translation offsets */
        xeon_set_pbar_xlat(ntb, peer_addr->bar2_addr64, NTB_B2B_BAR_1);
        if (HAS_FEATURE(ntb, NTB_SPLIT_BAR)) {
                xeon_set_pbar_xlat(ntb, peer_addr->bar4_addr32, NTB_B2B_BAR_2);
                xeon_set_pbar_xlat(ntb, peer_addr->bar5_addr32, NTB_B2B_BAR_3);
        } else
                xeon_set_pbar_xlat(ntb, peer_addr->bar4_addr64, NTB_B2B_BAR_2);

        /* Set the translation offset for B2B registers */
        bar_addr = 0;
        if (b2b_bar_num == NTB_CONFIG_BAR)
                bar_addr = peer_addr->bar0_addr;
        else if (b2b_bar_num == NTB_B2B_BAR_1)
                bar_addr = peer_addr->bar2_addr64;
        else if (b2b_bar_num == NTB_B2B_BAR_2 && !HAS_FEATURE(ntb, NTB_SPLIT_BAR))
                bar_addr = peer_addr->bar4_addr64;
        else if (b2b_bar_num == NTB_B2B_BAR_2)
                bar_addr = peer_addr->bar4_addr32;
        else if (b2b_bar_num == NTB_B2B_BAR_3)
                bar_addr = peer_addr->bar5_addr32;
        else
                KASSERT(false, ("invalid bar"));

        /*
         * B2B_XLAT_OFFSET is a 64-bit register but can only be written 32 bits
         * at a time.
         */
        intel_ntb_reg_write(4, XEON_B2B_XLAT_OFFSETL, bar_addr & 0xffffffff);
        intel_ntb_reg_write(4, XEON_B2B_XLAT_OFFSETU, bar_addr >> 32);
        return (0);
}

static int
xeon_gen3_setup_b2b_mw(struct ntb_softc *ntb)
{
        uint64_t reg;
        uint32_t embarsz, imbarsz;

        /* IMBAR1SZ should be equal to EMBAR1SZ */
        embarsz = pci_read_config(ntb->device, XEON_GEN3_INT_REG_EMBAR1SZ, 1);
        imbarsz = pci_read_config(ntb->device, XEON_GEN3_INT_REG_IMBAR1SZ, 1);
        if (embarsz != imbarsz) {
                device_printf(ntb->device,
                    "IMBAR1SZ (%u) should be equal to EMBAR1SZ (%u)\n",
                    imbarsz, embarsz);
                return (EIO);
        }

        /* IMBAR2SZ should be equal to EMBAR2SZ */
        embarsz = pci_read_config(ntb->device, XEON_GEN3_INT_REG_EMBAR2SZ, 1);
        imbarsz = pci_read_config(ntb->device, XEON_GEN3_INT_REG_IMBAR2SZ, 1);
        if (embarsz != imbarsz) {
                device_printf(ntb->device,
                    "IMBAR2SZ (%u) should be equal to EMBAR2SZ (%u)\n",
                    imbarsz, embarsz);
                return (EIO);
        }

        /* Client will provide the incoming IMBAR1/2XBASE, zero it for now */
        intel_ntb_reg_write(8, XEON_GEN3_REG_IMBAR1XBASE, 0);
        intel_ntb_reg_write(8, XEON_GEN3_REG_IMBAR2XBASE, 0);

        /*
         * If the value in IMBAR1XLIMIT is set equal to the value in IMBAR1XBASE,
         * the local memory window exposure from EMBAR1 is disabled.
         * Note: It is needed to avoid malicious access.
         */
        intel_ntb_reg_write(8, XEON_GEN3_REG_IMBAR1XLIMIT, 0);
        intel_ntb_reg_write(8, XEON_GEN3_REG_IMBAR2XLIMIT, 0);

        /* Config outgoing translation limits (whole bar size windows) */
        reg = intel_ntb_reg_read(8, XEON_GEN3_REG_EMBAR1XBASE);
        reg += ntb->bar_info[NTB_B2B_BAR_1].size;
        intel_ntb_reg_write(8, XEON_GEN3_REG_EMBAR1XLIMIT, reg);

        reg = intel_ntb_reg_read(8, XEON_GEN3_REG_EMBAR2XBASE);
        reg += ntb->bar_info[NTB_B2B_BAR_2].size;
        intel_ntb_reg_write(8, XEON_GEN3_REG_EMBAR2XLIMIT, reg);

        return (0);
}

static int
xeon_gen4_setup_b2b_mw(struct ntb_softc *ntb)
{
        uint32_t embarsz, imbarsz;

        /* IMBAR23SZ should be equal to EMBAR23SZ */
        imbarsz = pci_read_config(ntb->device, XEON_GEN4_CFG_REG_IMBAR1SZ, 1);
        embarsz = pci_read_config(ntb->device, XEON_GEN4_CFG_REG_EMBAR1SZ, 1);
        if (embarsz != imbarsz) {
                device_printf(ntb->device,
                    "IMBAR23SZ (%u) should be equal to EMBAR23SZ (%u)\n",
                    imbarsz, embarsz);
                return (EIO);
        }
        /* IMBAR45SZ should be equal to EMBAR45SZ */
        imbarsz = pci_read_config(ntb->device, XEON_GEN4_CFG_REG_IMBAR2SZ, 1);
        embarsz = pci_read_config(ntb->device, XEON_GEN4_CFG_REG_EMBAR2SZ, 1);
        if (embarsz != imbarsz) {
                device_printf(ntb->device,
                    "IMBAR45SZ (%u) should be equal to EMBAR45SZ (%u)\n",
                    imbarsz, embarsz);
                return (EIO);
        }

        /* Client will provide the incoming IMBARXBASE, zero it for now */
        intel_ntb_reg_write(8, XEON_GEN4_REG_IMBAR1XBASE, 0);
        intel_ntb_reg_write(8, XEON_GEN4_REG_IMBAR2XBASE, 0);

        /*
         * If the value in IMBARXLIMIT is set equal to the value in IMBARXBASE,
         * the local memory window exposure from EMBAR is disabled.
         * Note: It is needed to avoid malicious access.
         */
        intel_ntb_reg_write(8, XEON_GEN4_REG_IMBAR1XLIMIT, 0);
        intel_ntb_reg_write(8, XEON_GEN4_REG_IMBAR2XLIMIT, 0);

        /* EMBARXLIMIT & EMBARXBASE are gone for gen4, noop here */

        return (0);
}

static inline bool
_xeon_link_is_up(struct ntb_softc *ntb)
{

        if (ntb->conn_type == NTB_CONN_TRANSPARENT)
                return (true);
        return ((ntb->lnk_sta & NTB_LINK_STATUS_ACTIVE) != 0);
}

static inline bool
link_is_up(struct ntb_softc *ntb)
{

        if (ntb->type == NTB_XEON_GEN1 ||
            ntb->type == NTB_XEON_GEN3 ||
            ntb->type == NTB_XEON_GEN4)
                return (_xeon_link_is_up(ntb) && (ntb->peer_msix_good ||
                    !HAS_FEATURE(ntb, NTB_SB01BASE_LOCKUP)));

        KASSERT(ntb->type == NTB_ATOM, ("ntb type"));
        return ((ntb->ntb_ctl & ATOM_CNTL_LINK_DOWN) == 0);
}

static inline bool
atom_link_is_err(struct ntb_softc *ntb)
{
        uint32_t status;

        KASSERT(ntb->type == NTB_ATOM, ("ntb type"));

        status = intel_ntb_reg_read(4, ATOM_LTSSMSTATEJMP_OFFSET);
        if ((status & ATOM_LTSSMSTATEJMP_FORCEDETECT) != 0)
                return (true);

        status = intel_ntb_reg_read(4, ATOM_IBSTERRRCRVSTS0_OFFSET);
        return ((status & ATOM_IBIST_ERR_OFLOW) != 0);
}

/* Atom does not have link status interrupt, poll on that platform */
static void
atom_link_hb(void *arg)
{
        struct ntb_softc *ntb = arg;
        sbintime_t timo, poll_ts;

        timo = NTB_HB_TIMEOUT * hz;
        poll_ts = ntb->last_ts + timo;

        /*
         * Delay polling the link status if an interrupt was received, unless
         * the cached link status says the link is down.
         */
        if ((sbintime_t)ticks - poll_ts < 0 && link_is_up(ntb)) {
                timo = poll_ts - ticks;
                goto out;
        }

        if (intel_ntb_poll_link(ntb))
                ntb_link_event(ntb->device);

        if (!link_is_up(ntb) && atom_link_is_err(ntb)) {
                /* Link is down with error, proceed with recovery */
                callout_reset(&ntb->lr_timer, 0, recover_atom_link, ntb);
                return;
        }

out:
        callout_reset(&ntb->heartbeat_timer, timo, atom_link_hb, ntb);
}

static void
atom_perform_link_restart(struct ntb_softc *ntb)
{
        uint32_t status;

        /* Driver resets the NTB ModPhy lanes - magic! */
        intel_ntb_reg_write(1, ATOM_MODPHY_PCSREG6, 0xe0);
        intel_ntb_reg_write(1, ATOM_MODPHY_PCSREG4, 0x40);
        intel_ntb_reg_write(1, ATOM_MODPHY_PCSREG4, 0x60);
        intel_ntb_reg_write(1, ATOM_MODPHY_PCSREG6, 0x60);

        /* Driver waits 100ms to allow the NTB ModPhy to settle */
        pause("ModPhy", hz / 10);

        /* Clear AER Errors, write to clear */
        status = intel_ntb_reg_read(4, ATOM_ERRCORSTS_OFFSET);
        status &= PCIM_AER_COR_REPLAY_ROLLOVER;
        intel_ntb_reg_write(4, ATOM_ERRCORSTS_OFFSET, status);

        /* Clear unexpected electrical idle event in LTSSM, write to clear */
        status = intel_ntb_reg_read(4, ATOM_LTSSMERRSTS0_OFFSET);
        status |= ATOM_LTSSMERRSTS0_UNEXPECTEDEI;
        intel_ntb_reg_write(4, ATOM_LTSSMERRSTS0_OFFSET, status);

        /* Clear DeSkew Buffer error, write to clear */
        status = intel_ntb_reg_read(4, ATOM_DESKEWSTS_OFFSET);
        status |= ATOM_DESKEWSTS_DBERR;
        intel_ntb_reg_write(4, ATOM_DESKEWSTS_OFFSET, status);

        status = intel_ntb_reg_read(4, ATOM_IBSTERRRCRVSTS0_OFFSET);
        status &= ATOM_IBIST_ERR_OFLOW;
        intel_ntb_reg_write(4, ATOM_IBSTERRRCRVSTS0_OFFSET, status);

        /* Releases the NTB state machine to allow the link to retrain */
        status = intel_ntb_reg_read(4, ATOM_LTSSMSTATEJMP_OFFSET);
        status &= ~ATOM_LTSSMSTATEJMP_FORCEDETECT;
        intel_ntb_reg_write(4, ATOM_LTSSMSTATEJMP_OFFSET, status);
}

static int
intel_ntb_port_number(device_t dev)
{
        struct ntb_softc *ntb = device_get_softc(dev);

        return (ntb->dev_type == NTB_DEV_USD ? 0 : 1);
}

static int
intel_ntb_peer_port_count(device_t dev)
{

        return (1);
}

static int
intel_ntb_peer_port_number(device_t dev, int pidx)
{
        struct ntb_softc *ntb = device_get_softc(dev);

        if (pidx != 0)
                return (-EINVAL);

        return (ntb->dev_type == NTB_DEV_USD ? 1 : 0);
}

static int
intel_ntb_peer_port_idx(device_t dev, int port)
{
        int peer_port;

        peer_port = intel_ntb_peer_port_number(dev, 0);
        if (peer_port == -EINVAL || port != peer_port)
                return (-EINVAL);

        return (0);
}

static int
intel_ntb4_link_enable(device_t dev, enum ntb_speed speed __unused,
    enum ntb_width width __unused)
{
        struct ntb_softc *ntb = device_get_softc(dev);
        uint32_t cntl, ppd0, ltr;
        uint16_t lnkctl;

        if (!HAS_FEATURE(ntb, NTB_LTR_BAD)) {
                /* Setup active snoop LTR values */
                ltr = NTB_LTR_ACTIVE_REQMNT | NTB_LTR_ACTIVE_VAL | NTB_LTR_ACTIVE_LATSCALE;
                /* Setup active non-snoop values */
                ltr = (ltr << NTB_LTR_NS_SHIFT) | ltr;
                intel_ntb_reg_write(4, XEON_GEN4_REG_EXT_LTR_ACTIVE, ltr);

                /* Setup idle snoop LTR values */
                ltr = NTB_LTR_IDLE_VAL | NTB_LTR_IDLE_LATSCALE | NTB_LTR_IDLE_REQMNT;
                /* Setup idle non-snoop values */
                ltr = (ltr << NTB_LTR_NS_SHIFT) | ltr;
                intel_ntb_reg_write(4, XEON_GEN4_REG_EXT_LTR_IDLE, ltr);

                /* setup PCIe LTR to active */
                intel_ntb_reg_write(4, XEON_GEN4_REG_EXT_LTR_SWSEL, NTB_LTR_SWSEL_ACTIVE);
        }

        cntl = NTB_CTL_E2I_BAR23_SNOOP | NTB_CTL_I2E_BAR23_SNOOP;
        cntl |= NTB_CTL_E2I_BAR45_SNOOP | NTB_CTL_I2E_BAR45_SNOOP;
        intel_ntb_reg_write(4, ntb->reg->ntb_ctl, cntl);

        lnkctl = intel_ntb_reg_read(2, XEON_GEN4_REG_LINK_CTRL);
        lnkctl &= ~GEN4_LINK_CTRL_LINK_DISABLE;
        intel_ntb_reg_write(2, XEON_GEN4_REG_LINK_CTRL, lnkctl);

        /* start link training in PPD0 */
        ppd0 = intel_ntb_reg_read(4, XEON_GEN4_REG_PPD0);
        ppd0 |= GEN4_PPD_LINKTRN;
        intel_ntb_reg_write(4, XEON_GEN4_REG_PPD0, ppd0);

        /* make sure link training has started */
        ppd0 = intel_ntb_reg_read(4, XEON_GEN4_REG_PPD0);
        if (!(ppd0 & GEN4_PPD_LINKTRN))
                intel_ntb_printf(2, "Link is not training\n");

        return (0);
}

static int
intel_ntb_link_enable(device_t dev, enum ntb_speed speed __unused,
    enum ntb_width width __unused)
{
        struct ntb_softc *ntb = device_get_softc(dev);
        uint32_t cntl;

        intel_ntb_printf(2, "%s\n", __func__);

        if (ntb->type == NTB_XEON_GEN4)
                return (intel_ntb4_link_enable(dev, speed, width));

        if (ntb->type == NTB_ATOM) {
                pci_write_config(ntb->device, NTB_PPD_OFFSET,
                    ntb->ppd | ATOM_PPD_INIT_LINK, 4);
                return (0);
        }

        if (ntb->conn_type == NTB_CONN_TRANSPARENT) {
                ntb_link_event(dev);
                return (0);
        }

        cntl = intel_ntb_reg_read(4, ntb->reg->ntb_ctl);
        cntl &= ~(NTB_CNTL_LINK_DISABLE | NTB_CNTL_CFG_LOCK);
        cntl |= NTB_CNTL_P2S_BAR23_SNOOP | NTB_CNTL_S2P_BAR23_SNOOP;
        cntl |= NTB_CNTL_P2S_BAR4_SNOOP | NTB_CNTL_S2P_BAR4_SNOOP;
        if (HAS_FEATURE(ntb, NTB_SPLIT_BAR))
                cntl |= NTB_CNTL_P2S_BAR5_SNOOP | NTB_CNTL_S2P_BAR5_SNOOP;
        intel_ntb_reg_write(4, ntb->reg->ntb_ctl, cntl);
        return (0);
}

static int
intel_ntb4_link_disable(device_t dev)
{
        struct ntb_softc *ntb = device_get_softc(dev);
        uint32_t cntl;
        uint16_t lnkctl;

        /* clear the snoop bits */
        cntl = intel_ntb_reg_read(4, ntb->reg->ntb_ctl);
        cntl &= ~(NTB_CTL_E2I_BAR23_SNOOP | NTB_CTL_I2E_BAR23_SNOOP);
        cntl &= ~(NTB_CTL_E2I_BAR45_SNOOP | NTB_CTL_I2E_BAR45_SNOOP);
        intel_ntb_reg_write(4, ntb->reg->ntb_ctl, cntl);

        lnkctl = intel_ntb_reg_read(2, XEON_GEN4_REG_LINK_CTRL);
        lnkctl |= GEN4_LINK_CTRL_LINK_DISABLE;
        intel_ntb_reg_write(2, XEON_GEN4_REG_LINK_CTRL, lnkctl);

        /* set LTR to idle */
        if (!HAS_FEATURE(ntb, NTB_LTR_BAD))
                intel_ntb_reg_write(4, XEON_GEN4_REG_EXT_LTR_SWSEL, NTB_LTR_SWSEL_IDLE);

        return (0);
}

static int
intel_ntb_link_disable(device_t dev)
{
        struct ntb_softc *ntb = device_get_softc(dev);
        uint32_t cntl;

        intel_ntb_printf(2, "%s\n", __func__);

        if (ntb->type == NTB_XEON_GEN4)
                return (intel_ntb4_link_disable(dev));

        if (ntb->conn_type == NTB_CONN_TRANSPARENT) {
                ntb_link_event(dev);
                return (0);
        }

        cntl = intel_ntb_reg_read(4, ntb->reg->ntb_ctl);
        cntl &= ~(NTB_CNTL_P2S_BAR23_SNOOP | NTB_CNTL_S2P_BAR23_SNOOP);
        cntl &= ~(NTB_CNTL_P2S_BAR4_SNOOP | NTB_CNTL_S2P_BAR4_SNOOP);
        if (HAS_FEATURE(ntb, NTB_SPLIT_BAR))
                cntl &= ~(NTB_CNTL_P2S_BAR5_SNOOP | NTB_CNTL_S2P_BAR5_SNOOP);
        cntl |= NTB_CNTL_LINK_DISABLE | NTB_CNTL_CFG_LOCK;
        intel_ntb_reg_write(4, ntb->reg->ntb_ctl, cntl);
        return (0);
}

static bool
intel_ntb_link_enabled(device_t dev)
{
        struct ntb_softc *ntb = device_get_softc(dev);
        uint32_t cntl;

        if (ntb->type == NTB_ATOM) {
                cntl = pci_read_config(ntb->device, NTB_PPD_OFFSET, 4);
                return ((cntl & ATOM_PPD_INIT_LINK) != 0);
        }

        if (ntb->conn_type == NTB_CONN_TRANSPARENT)
                return (true);

        if (ntb->type == NTB_XEON_GEN4) {
                cntl = intel_ntb_reg_read(2, XEON_GEN4_REG_LINK_CTRL);
                return ((cntl & GEN4_LINK_CTRL_LINK_DISABLE) == 0);
        }

        cntl = intel_ntb_reg_read(4, ntb->reg->ntb_ctl);
        return ((cntl & NTB_CNTL_LINK_DISABLE) == 0);
}

static void
recover_atom_link(void *arg)
{
        struct ntb_softc *ntb = arg;
        unsigned speed, width, oldspeed, oldwidth;
        uint32_t status32;

        atom_perform_link_restart(ntb);

        /*
         * There is a potential race between the 2 NTB devices recovering at
         * the same time.  If the times are the same, the link will not recover
         * and the driver will be stuck in this loop forever.  Add a random
         * interval to the recovery time to prevent this race.
         */
        status32 = arc4random() % ATOM_LINK_RECOVERY_TIME;
        pause("Link", (ATOM_LINK_RECOVERY_TIME + status32) * hz / 1000);

        if (atom_link_is_err(ntb))
                goto retry;

        status32 = intel_ntb_reg_read(4, ntb->reg->ntb_ctl);
        if ((status32 & ATOM_CNTL_LINK_DOWN) != 0)
                goto out;

        status32 = intel_ntb_reg_read(4, ntb->reg->lnk_sta);
        width = NTB_LNK_STA_WIDTH(status32);
        speed = status32 & NTB_LINK_SPEED_MASK;

        oldwidth = NTB_LNK_STA_WIDTH(ntb->lnk_sta);
        oldspeed = ntb->lnk_sta & NTB_LINK_SPEED_MASK;
        if (oldwidth != width || oldspeed != speed)
                goto retry;

out:
        callout_reset(&ntb->heartbeat_timer, NTB_HB_TIMEOUT * hz, atom_link_hb,
            ntb);
        return;

retry:
        callout_reset(&ntb->lr_timer, NTB_HB_TIMEOUT * hz, recover_atom_link,
            ntb);
}

/*
 * Polls the HW link status register(s); returns true if something has changed.
 */
static bool
intel_ntb_atom_poll_link(struct ntb_softc *ntb)
{
        uint32_t ntb_cntl;

        ntb_cntl = intel_ntb_reg_read(4, ntb->reg->ntb_ctl);
        if (ntb_cntl == ntb->ntb_ctl)
                return (false);

        ntb->ntb_ctl = ntb_cntl;
        ntb->lnk_sta = intel_ntb_reg_read(4, ntb->reg->lnk_sta);
        return (true);
}

static bool
intel_ntb_xeon_gen1_poll_link(struct ntb_softc *ntb)
{
        uint16_t reg_val;

        if (ntb->type == NTB_XEON_GEN1)
                db_iowrite_raw(ntb, ntb->self_reg->db_bell,
                        ntb->db_link_mask);

        reg_val = pci_read_config(ntb->device, ntb->reg->lnk_sta, 2);
        if (reg_val == ntb->lnk_sta)
                return (false);

        ntb->lnk_sta = reg_val;

        if (HAS_FEATURE(ntb, NTB_SB01BASE_LOCKUP)) {
                if (_xeon_link_is_up(ntb)) {
                        if (!ntb->peer_msix_good) {
                                callout_reset(&ntb->peer_msix_work, 0,
                                    intel_ntb_exchange_msix, ntb);
                                return (false);
                        }
                } else {
                        ntb->peer_msix_good = false;
                        ntb->peer_msix_done = false;
                }
        }
        return (true);
}

static bool
intel_ntb_xeon_gen4_poll_link(struct ntb_softc *ntb)
{
        uint16_t reg_val;

        /*
        * We need to write to DLLSCS bit in the SLOTSTS before we
        * can clear the hardware link interrupt on ICX NTB.
        */
        intel_ntb_reg_write(2, XEON_GEN4_REG_SLOTSTS, GEN4_SLOTSTS_DLLSCS);
        db_iowrite_raw(ntb, ntb->self_reg->db_clear, ntb->db_link_mask);

        reg_val = intel_ntb_reg_read(2, ntb->reg->lnk_sta);
        if (reg_val == ntb->lnk_sta)
                return (false);

        ntb->lnk_sta = reg_val;
        return (true);
}

static bool
intel_ntb_poll_link(struct ntb_softc *ntb)
{
        bool val;

        switch(ntb->type) {
        case NTB_ATOM:
                val = intel_ntb_atom_poll_link(ntb);
                break;
        case NTB_XEON_GEN4:
                val = intel_ntb_xeon_gen4_poll_link(ntb);
                break;
        default:
                val = intel_ntb_xeon_gen1_poll_link(ntb);
                break;
        }
        return (val);
}

static inline enum ntb_speed
intel_ntb_link_sta_speed(struct ntb_softc *ntb)
{

        if (!link_is_up(ntb))
                return (NTB_SPEED_NONE);
        return (ntb->lnk_sta & NTB_LINK_SPEED_MASK);
}

static inline enum ntb_width
intel_ntb_link_sta_width(struct ntb_softc *ntb)
{

        if (!link_is_up(ntb))
                return (NTB_WIDTH_NONE);
        return (NTB_LNK_STA_WIDTH(ntb->lnk_sta));
}

SYSCTL_NODE(_hw_ntb, OID_AUTO, debug_info, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "Driver state, statistics, and HW registers");

#define NTB_REGSZ_MASK  (3ul << 30)
#define NTB_REG_64      (1ul << 30)
#define NTB_REG_32      (2ul << 30)
#define NTB_REG_16      (3ul << 30)
#define NTB_REG_8       (0ul << 30)

#define NTB_DB_READ     (1ul << 29)
#define NTB_PCI_REG     (1ul << 28)
#define NTB_REGFLAGS_MASK       (NTB_REGSZ_MASK | NTB_DB_READ | NTB_PCI_REG)

static void
intel_ntb_sysctl_init(struct ntb_softc *ntb)
{
        struct sysctl_oid_list *globals, *tree_par, *regpar, *statpar, *errpar;
        struct sysctl_ctx_list *ctx;
        struct sysctl_oid *tree, *tmptree;

        ctx = device_get_sysctl_ctx(ntb->device);
        globals = SYSCTL_CHILDREN(device_get_sysctl_tree(ntb->device));

        SYSCTL_ADD_PROC(ctx, globals, OID_AUTO, "link_status",
            CTLFLAG_RD | CTLTYPE_STRING | CTLFLAG_MPSAFE, ntb, 0,
            sysctl_handle_link_status_human, "A",
            "Link status (human readable)");
        SYSCTL_ADD_PROC(ctx, globals, OID_AUTO, "active",
            CTLFLAG_RD | CTLTYPE_UINT | CTLFLAG_MPSAFE, ntb, 0,
            sysctl_handle_link_status, "IU",
            "Link status (1=active, 0=inactive)");
        SYSCTL_ADD_PROC(ctx, globals, OID_AUTO, "admin_up",
            CTLFLAG_RW | CTLTYPE_UINT | CTLFLAG_MPSAFE, ntb, 0,
            sysctl_handle_link_admin, "IU",
            "Set/get interface status (1=UP, 0=DOWN)");

        tree = SYSCTL_ADD_NODE(ctx, globals, OID_AUTO, "debug_info",
            CTLFLAG_RD | CTLFLAG_MPSAFE, NULL,
            "Driver state, statistics, and HW registers");
        tree_par = SYSCTL_CHILDREN(tree);

        SYSCTL_ADD_UINT(ctx, tree_par, OID_AUTO, "conn_type", CTLFLAG_RD,
            &ntb->conn_type, 0, "0 - Transparent; 1 - B2B; 2 - Root Port");
        SYSCTL_ADD_UINT(ctx, tree_par, OID_AUTO, "dev_type", CTLFLAG_RD,
            &ntb->dev_type, 0, "0 - USD; 1 - DSD");
        SYSCTL_ADD_UINT(ctx, tree_par, OID_AUTO, "ppd", CTLFLAG_RD,
            &ntb->ppd, 0, "Raw PPD register (cached)");

        if (ntb->b2b_mw_idx != B2B_MW_DISABLED) {
                SYSCTL_ADD_U8(ctx, tree_par, OID_AUTO, "b2b_idx", CTLFLAG_RD,
                    &ntb->b2b_mw_idx, 0,
                    "Index of the MW used for B2B remote register access");
                SYSCTL_ADD_UQUAD(ctx, tree_par, OID_AUTO, "b2b_off",
                    CTLFLAG_RD, &ntb->b2b_off,
                    "If non-zero, offset of B2B register region in shared MW");
        }

        SYSCTL_ADD_PROC(ctx, tree_par, OID_AUTO, "features",
            CTLFLAG_RD | CTLTYPE_STRING | CTLFLAG_MPSAFE, ntb, 0,
            sysctl_handle_features, "A", "Features/errata of this NTB device");

        SYSCTL_ADD_UINT(ctx, tree_par, OID_AUTO, "ntb_ctl", CTLFLAG_RD,
            __DEVOLATILE(uint32_t *, &ntb->ntb_ctl), 0,
            "NTB CTL register (cached)");
        SYSCTL_ADD_UINT(ctx, tree_par, OID_AUTO, "lnk_sta", CTLFLAG_RD,
            __DEVOLATILE(uint32_t *, &ntb->lnk_sta), 0,
            "LNK STA register (cached)");

        SYSCTL_ADD_U8(ctx, tree_par, OID_AUTO, "mw_count", CTLFLAG_RD,
            &ntb->mw_count, 0, "MW count");
        SYSCTL_ADD_U8(ctx, tree_par, OID_AUTO, "spad_count", CTLFLAG_RD,
            &ntb->spad_count, 0, "Scratchpad count");
        SYSCTL_ADD_U8(ctx, tree_par, OID_AUTO, "db_count", CTLFLAG_RD,
            &ntb->db_count, 0, "Doorbell count");
        SYSCTL_ADD_U8(ctx, tree_par, OID_AUTO, "db_vec_count", CTLFLAG_RD,
            &ntb->db_vec_count, 0, "Doorbell vector count");
        SYSCTL_ADD_U8(ctx, tree_par, OID_AUTO, "db_vec_shift", CTLFLAG_RD,
            &ntb->db_vec_shift, 0, "Doorbell vector shift");

        SYSCTL_ADD_UQUAD(ctx, tree_par, OID_AUTO, "db_valid_mask", CTLFLAG_RD,
            &ntb->db_valid_mask, "Doorbell valid mask");
        SYSCTL_ADD_UQUAD(ctx, tree_par, OID_AUTO, "db_link_mask", CTLFLAG_RD,
            &ntb->db_link_mask, "Doorbell link mask");
        SYSCTL_ADD_UQUAD(ctx, tree_par, OID_AUTO, "db_mask", CTLFLAG_RD,
            &ntb->db_mask, "Doorbell mask (cached)");

        tmptree = SYSCTL_ADD_NODE(ctx, tree_par, OID_AUTO, "registers",
            CTLFLAG_RD | CTLFLAG_MPSAFE, NULL,
            "Raw HW registers (big-endian)");
        regpar = SYSCTL_CHILDREN(tmptree);

        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "ntbcntl",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_32 | ntb->reg->ntb_ctl, sysctl_handle_register, "IU",
            "NTB Control register");
        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "lnkcap",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_32 | 0x19c, sysctl_handle_register, "IU",
            "NTB Link Capabilities");
        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "lnkcon",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_32 | 0x1a0, sysctl_handle_register, "IU",
            "NTB Link Control register");

        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "db_mask",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_64 | NTB_DB_READ | ntb->self_reg->db_mask,
            sysctl_handle_register, "QU", "Doorbell mask register");
        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "db_bell",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_64 | NTB_DB_READ | ntb->self_reg->db_bell,
            sysctl_handle_register, "QU", "Doorbell register");

        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "incoming_xlat23",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_64 | ntb->xlat_reg->bar2_xlat,
            sysctl_handle_register, "QU", "Incoming XLAT23 register");
        if (HAS_FEATURE(ntb, NTB_SPLIT_BAR)) {
                SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "incoming_xlat4",
                    CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
                    NTB_REG_32 | ntb->xlat_reg->bar4_xlat,
                    sysctl_handle_register, "IU", "Incoming XLAT4 register");
                SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "incoming_xlat5",
                    CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
                    NTB_REG_32 | ntb->xlat_reg->bar5_xlat,
                    sysctl_handle_register, "IU", "Incoming XLAT5 register");
        } else {
                SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "incoming_xlat45",
                    CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
                    NTB_REG_64 | ntb->xlat_reg->bar4_xlat,
                    sysctl_handle_register, "QU", "Incoming XLAT45 register");
        }

        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "incoming_lmt23",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_64 | ntb->xlat_reg->bar2_limit,
            sysctl_handle_register, "QU", "Incoming LMT23 register");
        if (HAS_FEATURE(ntb, NTB_SPLIT_BAR)) {
                SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "incoming_lmt4",
                    CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
                    NTB_REG_32 | ntb->xlat_reg->bar4_limit,
                    sysctl_handle_register, "IU", "Incoming LMT4 register");
                SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "incoming_lmt5",
                    CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
                    NTB_REG_32 | ntb->xlat_reg->bar5_limit,
                    sysctl_handle_register, "IU", "Incoming LMT5 register");
        } else {
                SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "incoming_lmt45",
                    CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
                    NTB_REG_64 | ntb->xlat_reg->bar4_limit,
                    sysctl_handle_register, "QU", "Incoming LMT45 register");
        }

        if (ntb->type == NTB_ATOM)
                return;

        tmptree = SYSCTL_ADD_NODE(ctx, regpar, OID_AUTO, "xeon_stats",
            CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, "Xeon HW statistics");
        statpar = SYSCTL_CHILDREN(tmptree);
        SYSCTL_ADD_PROC(ctx, statpar, OID_AUTO, "upstream_mem_miss",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_16 | XEON_USMEMMISS_OFFSET,
            sysctl_handle_register, "SU", "Upstream Memory Miss");

        tmptree = SYSCTL_ADD_NODE(ctx, regpar, OID_AUTO, "xeon_hw_err",
            CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, "Xeon HW errors");
        errpar = SYSCTL_CHILDREN(tmptree);

        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "ppd",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_8 | NTB_PCI_REG | NTB_PPD_OFFSET,
            sysctl_handle_register, "CU", "PPD");

        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "pbar23_sz",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_8 | NTB_PCI_REG | XEON_PBAR23SZ_OFFSET,
            sysctl_handle_register, "CU", "PBAR23 SZ (log2)");
        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "pbar4_sz",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_8 | NTB_PCI_REG | XEON_PBAR4SZ_OFFSET,
            sysctl_handle_register, "CU", "PBAR4 SZ (log2)");
        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "pbar5_sz",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_8 | NTB_PCI_REG | XEON_PBAR5SZ_OFFSET,
            sysctl_handle_register, "CU", "PBAR5 SZ (log2)");

        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "sbar23_sz",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_8 | NTB_PCI_REG | XEON_SBAR23SZ_OFFSET,
            sysctl_handle_register, "CU", "SBAR23 SZ (log2)");
        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "sbar4_sz",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_8 | NTB_PCI_REG | XEON_SBAR4SZ_OFFSET,
            sysctl_handle_register, "CU", "SBAR4 SZ (log2)");
        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "sbar5_sz",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_8 | NTB_PCI_REG | XEON_SBAR5SZ_OFFSET,
            sysctl_handle_register, "CU", "SBAR5 SZ (log2)");

        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "devsts",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_16 | NTB_PCI_REG | XEON_DEVSTS_OFFSET,
            sysctl_handle_register, "SU", "DEVSTS");
        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "lnksts",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_16 | NTB_PCI_REG | XEON_LINK_STATUS_OFFSET,
            sysctl_handle_register, "SU", "LNKSTS");
        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "slnksts",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_16 | NTB_PCI_REG | XEON_SLINK_STATUS_OFFSET,
            sysctl_handle_register, "SU", "SLNKSTS");

        SYSCTL_ADD_PROC(ctx, errpar, OID_AUTO, "uncerrsts",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_32 | NTB_PCI_REG | XEON_UNCERRSTS_OFFSET,
            sysctl_handle_register, "IU", "UNCERRSTS");
        SYSCTL_ADD_PROC(ctx, errpar, OID_AUTO, "corerrsts",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_32 | NTB_PCI_REG | XEON_CORERRSTS_OFFSET,
            sysctl_handle_register, "IU", "CORERRSTS");

        if (ntb->conn_type != NTB_CONN_B2B)
                return;

        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "outgoing_xlat01l",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_32 | XEON_B2B_XLAT_OFFSETL,
            sysctl_handle_register, "IU", "Outgoing XLAT0L register");
        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "outgoing_xlat01u",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_32 | XEON_B2B_XLAT_OFFSETU,
            sysctl_handle_register, "IU", "Outgoing XLAT0U register");
        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "outgoing_xlat23",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_64 | ntb->bar_info[NTB_B2B_BAR_1].pbarxlat_off,
            sysctl_handle_register, "QU", "Outgoing XLAT23 register");
        if (HAS_FEATURE(ntb, NTB_SPLIT_BAR)) {
                SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "outgoing_xlat4",
                    CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
                    NTB_REG_32 | ntb->bar_info[NTB_B2B_BAR_2].pbarxlat_off,
                    sysctl_handle_register, "IU", "Outgoing XLAT4 register");
                SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "outgoing_xlat5",
                    CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
                    NTB_REG_32 | ntb->bar_info[NTB_B2B_BAR_3].pbarxlat_off,
                    sysctl_handle_register, "IU", "Outgoing XLAT5 register");
        } else {
                SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "outgoing_xlat45",
                    CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
                    NTB_REG_64 | ntb->bar_info[NTB_B2B_BAR_2].pbarxlat_off,
                    sysctl_handle_register, "QU", "Outgoing XLAT45 register");
        }

        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "outgoing_lmt23",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_64 | XEON_PBAR2LMT_OFFSET,
            sysctl_handle_register, "QU", "Outgoing LMT23 register");
        if (HAS_FEATURE(ntb, NTB_SPLIT_BAR)) {
                SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "outgoing_lmt4",
                    CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
                    NTB_REG_32 | XEON_PBAR4LMT_OFFSET,
                    sysctl_handle_register, "IU", "Outgoing LMT4 register");
                SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "outgoing_lmt5",
                    CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
                    NTB_REG_32 | XEON_PBAR5LMT_OFFSET,
                    sysctl_handle_register, "IU", "Outgoing LMT5 register");
        } else {
                SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "outgoing_lmt45",
                    CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
                    NTB_REG_64 | XEON_PBAR4LMT_OFFSET,
                    sysctl_handle_register, "QU", "Outgoing LMT45 register");
        }

        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "sbar01_base",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_64 | ntb->xlat_reg->bar0_base,
            sysctl_handle_register, "QU", "Secondary BAR01 base register");
        SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "sbar23_base",
            CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
            NTB_REG_64 | ntb->xlat_reg->bar2_base,
            sysctl_handle_register, "QU", "Secondary BAR23 base register");
        if (HAS_FEATURE(ntb, NTB_SPLIT_BAR)) {
                SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "sbar4_base",
                    CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
                    NTB_REG_32 | ntb->xlat_reg->bar4_base,
                    sysctl_handle_register, "IU",
                    "Secondary BAR4 base register");
                SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "sbar5_base",
                    CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
                    NTB_REG_32 | ntb->xlat_reg->bar5_base,
                    sysctl_handle_register, "IU",
                    "Secondary BAR5 base register");
        } else {
                SYSCTL_ADD_PROC(ctx, regpar, OID_AUTO, "sbar45_base",
                    CTLFLAG_RD | CTLTYPE_OPAQUE | CTLFLAG_MPSAFE, ntb,
                    NTB_REG_64 | ntb->xlat_reg->bar4_base,
                    sysctl_handle_register, "QU",
                    "Secondary BAR45 base register");
        }
}

static int
sysctl_handle_features(SYSCTL_HANDLER_ARGS)
{
        struct ntb_softc *ntb = arg1;
        struct sbuf sb;
        int error;

        sbuf_new_for_sysctl(&sb, NULL, 256, req);

        sbuf_printf(&sb, "%b", ntb->features, NTB_FEATURES_STR);
        error = sbuf_finish(&sb);
        sbuf_delete(&sb);

        if (error || !req->newptr)
                return (error);
        return (EINVAL);
}

static int
sysctl_handle_link_admin(SYSCTL_HANDLER_ARGS)
{
        struct ntb_softc *ntb = arg1;
        unsigned old, new;
        int error;

        old = intel_ntb_link_enabled(ntb->device);

        error = SYSCTL_OUT(req, &old, sizeof(old));
        if (error != 0 || req->newptr == NULL)
                return (error);

        error = SYSCTL_IN(req, &new, sizeof(new));
        if (error != 0)
                return (error);

        intel_ntb_printf(0, "Admin set interface state to '%sabled'\n",
            (new != 0)? "en" : "dis");

        if (new != 0)
                error = intel_ntb_link_enable(ntb->device, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
        else
                error = intel_ntb_link_disable(ntb->device);
        return (error);
}

static int
sysctl_handle_link_status_human(SYSCTL_HANDLER_ARGS)
{
        struct ntb_softc *ntb = arg1;
        struct sbuf sb;
        enum ntb_speed speed;
        enum ntb_width width;
        int error;

        sbuf_new_for_sysctl(&sb, NULL, 32, req);

        if (intel_ntb_link_is_up(ntb->device, &speed, &width))
                sbuf_printf(&sb, "up / PCIe Gen %u / Width x%u",
                    (unsigned)speed, (unsigned)width);
        else
                sbuf_printf(&sb, "down");

        error = sbuf_finish(&sb);
        sbuf_delete(&sb);

        if (error || !req->newptr)
                return (error);
        return (EINVAL);
}

static int
sysctl_handle_link_status(SYSCTL_HANDLER_ARGS)
{
        struct ntb_softc *ntb = arg1;
        unsigned res;
        int error;

        res = intel_ntb_link_is_up(ntb->device, NULL, NULL);

        error = SYSCTL_OUT(req, &res, sizeof(res));
        if (error || !req->newptr)
                return (error);
        return (EINVAL);
}

static int
sysctl_handle_register(SYSCTL_HANDLER_ARGS)
{
        struct ntb_softc *ntb;
        const void *outp;
        uintptr_t sz;
        uint64_t umv;
        char be[sizeof(umv)];
        size_t outsz;
        uint32_t reg;
        bool db, pci;
        int error;

        ntb = arg1;
        reg = arg2 & ~NTB_REGFLAGS_MASK;
        sz = arg2 & NTB_REGSZ_MASK;
        db = (arg2 & NTB_DB_READ) != 0;
        pci = (arg2 & NTB_PCI_REG) != 0;

        KASSERT(!(db && pci), ("bogus"));

        if (db) {
                KASSERT(sz == NTB_REG_64, ("bogus"));
                umv = db_ioread(ntb, reg);
                outsz = sizeof(uint64_t);
        } else {
                switch (sz) {
                case NTB_REG_64:
                        if (pci)
                                umv = pci_read_config(ntb->device, reg, 8);
                        else
                                umv = intel_ntb_reg_read(8, reg);
                        outsz = sizeof(uint64_t);
                        break;
                case NTB_REG_32:
                        if (pci)
                                umv = pci_read_config(ntb->device, reg, 4);
                        else
                                umv = intel_ntb_reg_read(4, reg);
                        outsz = sizeof(uint32_t);
                        break;
                case NTB_REG_16:
                        if (pci)
                                umv = pci_read_config(ntb->device, reg, 2);
                        else
                                umv = intel_ntb_reg_read(2, reg);
                        outsz = sizeof(uint16_t);
                        break;
                case NTB_REG_8:
                        if (pci)
                                umv = pci_read_config(ntb->device, reg, 1);
                        else
                                umv = intel_ntb_reg_read(1, reg);
                        outsz = sizeof(uint8_t);
                        break;
                default:
                        panic("bogus");
                        break;
                }
        }

        /* Encode bigendian so that sysctl -x is legible. */
        be64enc(be, umv);
        outp = ((char *)be) + sizeof(umv) - outsz;

        error = SYSCTL_OUT(req, outp, outsz);
        if (error || !req->newptr)
                return (error);
        return (EINVAL);
}

static unsigned
intel_ntb_user_mw_to_idx(struct ntb_softc *ntb, unsigned uidx)
{

        if ((ntb->b2b_mw_idx != B2B_MW_DISABLED && ntb->b2b_off == 0 &&
            uidx >= ntb->b2b_mw_idx) ||
            (ntb->msix_mw_idx != B2B_MW_DISABLED && uidx >= ntb->msix_mw_idx))
                uidx++;
        if ((ntb->b2b_mw_idx != B2B_MW_DISABLED && ntb->b2b_off == 0 &&
            uidx >= ntb->b2b_mw_idx) &&
            (ntb->msix_mw_idx != B2B_MW_DISABLED && uidx >= ntb->msix_mw_idx))
                uidx++;
        return (uidx);
}

#ifndef EARLY_AP_STARTUP
static int msix_ready;

static void
intel_ntb_msix_ready(void *arg __unused)
{

        msix_ready = 1;
}
SYSINIT(intel_ntb_msix_ready, SI_SUB_SMP, SI_ORDER_ANY,
    intel_ntb_msix_ready, NULL);
#endif

static void
intel_ntb_exchange_msix(void *ctx)
{
        struct ntb_softc *ntb;
        uint32_t val;
        unsigned i;

        ntb = ctx;

        if (ntb->peer_msix_good)
                goto msix_good;
        if (ntb->peer_msix_done)
                goto msix_done;

#ifndef EARLY_AP_STARTUP
        /* Block MSIX negotiation until SMP started and IRQ reshuffled. */
        if (!msix_ready)
                goto reschedule;
#endif

        intel_ntb_get_msix_info(ntb);
        for (i = 0; i < XEON_NONLINK_DB_MSIX_BITS; i++) {
                intel_ntb_peer_spad_write(ntb->device, NTB_MSIX_DATA0 + i,
                    ntb->msix_data[i].nmd_data);
                intel_ntb_peer_spad_write(ntb->device, NTB_MSIX_OFS0 + i,
                    ntb->msix_data[i].nmd_ofs - ntb->msix_xlat);
        }
        intel_ntb_peer_spad_write(ntb->device, NTB_MSIX_GUARD, NTB_MSIX_VER_GUARD);

        intel_ntb_spad_read(ntb->device, NTB_MSIX_GUARD, &val);
        if (val != NTB_MSIX_VER_GUARD)
                goto reschedule;

        for (i = 0; i < XEON_NONLINK_DB_MSIX_BITS; i++) {
                intel_ntb_spad_read(ntb->device, NTB_MSIX_DATA0 + i, &val);
                intel_ntb_printf(2, "remote MSIX data(%u): 0x%x\n", i, val);
                ntb->peer_msix_data[i].nmd_data = val;
                intel_ntb_spad_read(ntb->device, NTB_MSIX_OFS0 + i, &val);
                intel_ntb_printf(2, "remote MSIX addr(%u): 0x%x\n", i, val);
                ntb->peer_msix_data[i].nmd_ofs = val;
        }

        ntb->peer_msix_done = true;

msix_done:
        intel_ntb_peer_spad_write(ntb->device, NTB_MSIX_DONE, NTB_MSIX_RECEIVED);
        intel_ntb_spad_read(ntb->device, NTB_MSIX_DONE, &val);
        if (val != NTB_MSIX_RECEIVED)
                goto reschedule;

        intel_ntb_spad_clear(ntb->device);
        ntb->peer_msix_good = true;
        /* Give peer time to see our NTB_MSIX_RECEIVED. */
        goto reschedule;

msix_good:
        intel_ntb_poll_link(ntb);
        ntb_link_event(ntb->device);
        return;

reschedule:
        ntb->lnk_sta = pci_read_config(ntb->device, ntb->reg->lnk_sta, 2);
        if (_xeon_link_is_up(ntb)) {
                callout_reset(&ntb->peer_msix_work,
                    hz * (ntb->peer_msix_good ? 2 : 1) / 10,
                    intel_ntb_exchange_msix, ntb);
        } else
                intel_ntb_spad_clear(ntb->device);
}

/*
 * Public API to the rest of the OS
 */

static uint8_t
intel_ntb_spad_count(device_t dev)
{
        struct ntb_softc *ntb = device_get_softc(dev);

        return (ntb->spad_count);
}

static uint8_t
intel_ntb_mw_count(device_t dev)
{
        struct ntb_softc *ntb = device_get_softc(dev);
        uint8_t res;

        res = ntb->mw_count;
        if (ntb->b2b_mw_idx != B2B_MW_DISABLED && ntb->b2b_off == 0)
                res--;
        if (ntb->msix_mw_idx != B2B_MW_DISABLED)
                res--;
        return (res);
}

static int
intel_ntb_spad_write(device_t dev, unsigned int idx, uint32_t val)
{
        struct ntb_softc *ntb = device_get_softc(dev);

        if (idx >= ntb->spad_count)
                return (EINVAL);

        intel_ntb_reg_write(4, ntb->self_reg->spad + idx * 4, val);

        return (0);
}

/*
 * Zeros the local scratchpad.
 */
static void
intel_ntb_spad_clear(device_t dev)
{
        struct ntb_softc *ntb = device_get_softc(dev);
        unsigned i;

        for (i = 0; i < ntb->spad_count; i++)
                intel_ntb_spad_write(dev, i, 0);
}

static int
intel_ntb_spad_read(device_t dev, unsigned int idx, uint32_t *val)
{
        struct ntb_softc *ntb = device_get_softc(dev);

        if (idx >= ntb->spad_count)
                return (EINVAL);

        *val = intel_ntb_reg_read(4, ntb->self_reg->spad + idx * 4);

        return (0);
}

static int
intel_ntb_peer_spad_write(device_t dev, unsigned int idx, uint32_t val)
{
        struct ntb_softc *ntb = device_get_softc(dev);

        if (idx >= ntb->spad_count)
                return (EINVAL);

        if (HAS_FEATURE(ntb, NTB_SDOORBELL_LOCKUP))
                intel_ntb_mw_write(4, XEON_SPAD_OFFSET + idx * 4, val);
        else
                intel_ntb_reg_write(4, ntb->peer_reg->spad + idx * 4, val);

        return (0);
}

static int
intel_ntb_peer_spad_read(device_t dev, unsigned int idx, uint32_t *val)
{
        struct ntb_softc *ntb = device_get_softc(dev);

        if (idx >= ntb->spad_count)
                return (EINVAL);

        if (HAS_FEATURE(ntb, NTB_SDOORBELL_LOCKUP))
                *val = intel_ntb_mw_read(4, XEON_SPAD_OFFSET + idx * 4);
        else
                *val = intel_ntb_reg_read(4, ntb->peer_reg->spad + idx * 4);

        return (0);
}

static int
intel_ntb_mw_get_range(device_t dev, unsigned mw_idx, vm_paddr_t *base,
    caddr_t *vbase, size_t *size, size_t *align, size_t *align_size,
    bus_addr_t *plimit)
{
        struct ntb_softc *ntb = device_get_softc(dev);
        struct ntb_pci_bar_info *bar;
        bus_addr_t limit;
        size_t bar_b2b_off;
        enum ntb_bar bar_num;

        if (mw_idx >= intel_ntb_mw_count(dev))
                return (EINVAL);
        mw_idx = intel_ntb_user_mw_to_idx(ntb, mw_idx);

        bar_num = intel_ntb_mw_to_bar(ntb, mw_idx);
        bar = &ntb->bar_info[bar_num];
        bar_b2b_off = 0;
        if (mw_idx == ntb->b2b_mw_idx) {
                KASSERT(ntb->b2b_off != 0,
                    ("user shouldn't get non-shared b2b mw"));
                bar_b2b_off = ntb->b2b_off;
        }

        if (bar_is_64bit(ntb, bar_num))
                limit = BUS_SPACE_MAXADDR;
        else
                limit = BUS_SPACE_MAXADDR_32BIT;

        if (base != NULL)
                *base = bar->pbase + bar_b2b_off;
        if (vbase != NULL)
                *vbase = bar->vbase + bar_b2b_off;
        if (size != NULL)
                *size = bar->size - bar_b2b_off;
        if (align != NULL)
                *align = bar->size;
        if (align_size != NULL)
                *align_size = 1;
        if (plimit != NULL)
                *plimit = limit;
        return (0);
}

static int
intel_ntb_mw_set_trans(device_t dev, unsigned idx, bus_addr_t addr, size_t size)
{
        struct ntb_softc *ntb = device_get_softc(dev);
        struct ntb_pci_bar_info *bar;
        uint64_t base, limit, reg_val;
        size_t bar_size, mw_size;
        uint32_t base_reg, xlat_reg, limit_reg;
        enum ntb_bar bar_num;

        if (idx >= intel_ntb_mw_count(dev))
                return (EINVAL);
        idx = intel_ntb_user_mw_to_idx(ntb, idx);

        bar_num = intel_ntb_mw_to_bar(ntb, idx);
        bar = &ntb->bar_info[bar_num];

        bar_size = bar->size;
        if (idx == ntb->b2b_mw_idx)
                mw_size = bar_size - ntb->b2b_off;
        else
                mw_size = bar_size;

        /* Hardware requires that addr is aligned to bar size */
        if ((addr & (bar_size - 1)) != 0)
                return (EINVAL);

        if (size > mw_size)
                return (EINVAL);

        bar_get_xlat_params(ntb, bar_num, &base_reg, &xlat_reg, &limit_reg);

        limit = 0;
        if (bar_is_64bit(ntb, bar_num)) {
                if (ntb->type == NTB_XEON_GEN3 || ntb->type == NTB_XEON_GEN4)
                        base = addr;
                else
                        base = intel_ntb_reg_read(8, base_reg) & BAR_HIGH_MASK;

                if (limit_reg != 0 && size != mw_size)
                        limit = base + size;
                else
                        limit = base + mw_size;

                /* Set and verify translation address */
                intel_ntb_reg_write(8, xlat_reg, addr);
                reg_val = intel_ntb_reg_read(8, xlat_reg) & BAR_HIGH_MASK;
                if (reg_val != addr) {
                        intel_ntb_reg_write(8, xlat_reg, 0);
                        return (EIO);
                }

                /* Set and verify the limit */
                intel_ntb_reg_write(8, limit_reg, limit);
                reg_val = intel_ntb_reg_read(8, limit_reg) & BAR_HIGH_MASK;
                if (reg_val != limit) {
                        intel_ntb_reg_write(8, limit_reg, base);
                        intel_ntb_reg_write(8, xlat_reg, 0);
                        return (EIO);
                }
        } else {
                /* Configure 32-bit (split) BAR MW */
                if (ntb->type == NTB_XEON_GEN3 || ntb->type == NTB_XEON_GEN4)
                        return (EIO);

                if ((addr & UINT32_MAX) != addr)
                        return (ERANGE);
                if (((addr + size) & UINT32_MAX) != (addr + size))
                        return (ERANGE);

                base = intel_ntb_reg_read(4, base_reg) & BAR_HIGH_MASK;

                if (limit_reg != 0 && size != mw_size)
                        limit = base + size;

                /* Set and verify translation address */
                intel_ntb_reg_write(4, xlat_reg, addr);
                reg_val = intel_ntb_reg_read(4, xlat_reg) & BAR_HIGH_MASK;
                if (reg_val != addr) {
                        intel_ntb_reg_write(4, xlat_reg, 0);
                        return (EIO);
                }

                /* Set and verify the limit */
                intel_ntb_reg_write(4, limit_reg, limit);
                reg_val = intel_ntb_reg_read(4, limit_reg) & BAR_HIGH_MASK;
                if (reg_val != limit) {
                        intel_ntb_reg_write(4, limit_reg, base);
                        intel_ntb_reg_write(4, xlat_reg, 0);
                        return (EIO);
                }
        }
        return (0);
}

static int
intel_ntb_mw_clear_trans(device_t dev, unsigned mw_idx)
{

        return (intel_ntb_mw_set_trans(dev, mw_idx, 0, 0));
}

static int
intel_ntb_mw_get_wc(device_t dev, unsigned idx, vm_memattr_t *mode)
{
        struct ntb_softc *ntb = device_get_softc(dev);
        struct ntb_pci_bar_info *bar;

        if (idx >= intel_ntb_mw_count(dev))
                return (EINVAL);
        idx = intel_ntb_user_mw_to_idx(ntb, idx);

        bar = &ntb->bar_info[intel_ntb_mw_to_bar(ntb, idx)];
        *mode = bar->map_mode;
        return (0);
}

static int
intel_ntb_mw_set_wc(device_t dev, unsigned idx, vm_memattr_t mode)
{
        struct ntb_softc *ntb = device_get_softc(dev);

        if (idx >= intel_ntb_mw_count(dev))
                return (EINVAL);

        idx = intel_ntb_user_mw_to_idx(ntb, idx);
        return (intel_ntb_mw_set_wc_internal(ntb, idx, mode));
}

static int
intel_ntb_mw_set_wc_internal(struct ntb_softc *ntb, unsigned idx, vm_memattr_t mode)
{
        struct ntb_pci_bar_info *bar;
        int rc;

        bar = &ntb->bar_info[intel_ntb_mw_to_bar(ntb, idx)];
        if (bar->map_mode == mode)
                return (0);

        rc = pmap_change_attr(bar->vbase, bar->size, mode);
        if (rc == 0)
                bar->map_mode = mode;

        return (rc);
}

static void
intel_ntb_peer_db_set(device_t dev, uint64_t bits)
{
        struct ntb_softc *ntb = device_get_softc(dev);
        uint64_t db;

        if ((bits & ~ntb->db_valid_mask) != 0) {
                device_printf(ntb->device, "Invalid doorbell bits %#jx\n",
                    (uintmax_t)bits);
                return;
        }

        if (HAS_FEATURE(ntb, NTB_SB01BASE_LOCKUP)) {
                struct ntb_pci_bar_info *lapic;
                unsigned i;

                lapic = ntb->peer_lapic_bar;

                for (i = 0; i < XEON_NONLINK_DB_MSIX_BITS; i++) {
                        if ((bits & intel_ntb_db_vector_mask(dev, i)) != 0)
                                bus_space_write_4(lapic->pci_bus_tag,
                                    lapic->pci_bus_handle,
                                    ntb->peer_msix_data[i].nmd_ofs,
                                    ntb->peer_msix_data[i].nmd_data);
                }
                return;
        }

        if (HAS_FEATURE(ntb, NTB_SDOORBELL_LOCKUP)) {
                intel_ntb_mw_write(2, XEON_PDOORBELL_OFFSET, bits);
                return;
        }

        if (ntb->type == NTB_XEON_GEN3 || ntb->type == NTB_XEON_GEN4) {
                while (bits != 0) {
                        db = ffsll(bits);

                        intel_ntb_reg_write(1,
                            ntb->peer_reg->db_bell + (db - 1) * 4, 0x1);

                        bits = bits & (bits - 1);
                }
        } else {
                db_iowrite(ntb, ntb->peer_reg->db_bell, bits);
        }
}

static int
intel_ntb_peer_db_addr(device_t dev, bus_addr_t *db_addr, vm_size_t *db_size)
{
        struct ntb_softc *ntb = device_get_softc(dev);
        struct ntb_pci_bar_info *bar;
        uint64_t regoff;

        KASSERT((db_addr != NULL && db_size != NULL), ("must be non-NULL"));

        if (!HAS_FEATURE(ntb, NTB_SDOORBELL_LOCKUP)) {
                bar = &ntb->bar_info[NTB_CONFIG_BAR];
                regoff = ntb->peer_reg->db_bell;
        } else {
                KASSERT(ntb->b2b_mw_idx != B2B_MW_DISABLED,
                    ("invalid b2b idx"));

                bar = &ntb->bar_info[intel_ntb_mw_to_bar(ntb, ntb->b2b_mw_idx)];
                regoff = XEON_PDOORBELL_OFFSET;
        }
        KASSERT(bar->pci_bus_tag != X86_BUS_SPACE_IO, ("uh oh"));

        /* HACK: Specific to current x86 bus implementation. */
        *db_addr = ((uint64_t)bar->pci_bus_handle + regoff);
        *db_size = ntb->reg->db_size;
        return (0);
}

static uint64_t
intel_ntb_db_valid_mask(device_t dev)
{
        struct ntb_softc *ntb = device_get_softc(dev);

        return (ntb->db_valid_mask);
}

static int
intel_ntb_db_vector_count(device_t dev)
{
        struct ntb_softc *ntb = device_get_softc(dev);

        return (ntb->db_vec_count);
}

static uint64_t
intel_ntb_db_vector_mask(device_t dev, uint32_t vector)
{
        struct ntb_softc *ntb = device_get_softc(dev);

        if (vector > ntb->db_vec_count)
                return (0);
        return (ntb->db_valid_mask & intel_ntb_vec_mask(ntb, vector));
}

static bool
intel_ntb_link_is_up(device_t dev, enum ntb_speed *speed, enum ntb_width *width)
{
        struct ntb_softc *ntb = device_get_softc(dev);

        if (speed != NULL)
                *speed = intel_ntb_link_sta_speed(ntb);
        if (width != NULL)
                *width = intel_ntb_link_sta_width(ntb);
        return (link_is_up(ntb));
}

static void
save_bar_parameters(struct ntb_pci_bar_info *bar)
{

        bar->pci_bus_tag = rman_get_bustag(bar->pci_resource);
        bar->pci_bus_handle = rman_get_bushandle(bar->pci_resource);
        bar->pbase = rman_get_start(bar->pci_resource);
        bar->size = rman_get_size(bar->pci_resource);
        bar->vbase = rman_get_virtual(bar->pci_resource);
}

static device_method_t ntb_intel_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         intel_ntb_probe),
        DEVMETHOD(device_attach,        intel_ntb_attach),
        DEVMETHOD(device_detach,        intel_ntb_detach),
        /* Bus interface */
        DEVMETHOD(bus_child_location,   ntb_child_location),
        DEVMETHOD(bus_print_child,      ntb_print_child),
        DEVMETHOD(bus_get_dma_tag,      ntb_get_dma_tag),
        /* NTB interface */
        DEVMETHOD(ntb_port_number,      intel_ntb_port_number),
        DEVMETHOD(ntb_peer_port_count,  intel_ntb_peer_port_count),
        DEVMETHOD(ntb_peer_port_number, intel_ntb_peer_port_number),
        DEVMETHOD(ntb_peer_port_idx,    intel_ntb_peer_port_idx),
        DEVMETHOD(ntb_link_is_up,       intel_ntb_link_is_up),
        DEVMETHOD(ntb_link_enable,      intel_ntb_link_enable),
        DEVMETHOD(ntb_link_disable,     intel_ntb_link_disable),
        DEVMETHOD(ntb_link_enabled,     intel_ntb_link_enabled),
        DEVMETHOD(ntb_mw_count,         intel_ntb_mw_count),
        DEVMETHOD(ntb_mw_get_range,     intel_ntb_mw_get_range),
        DEVMETHOD(ntb_mw_set_trans,     intel_ntb_mw_set_trans),
        DEVMETHOD(ntb_mw_clear_trans,   intel_ntb_mw_clear_trans),
        DEVMETHOD(ntb_mw_get_wc,        intel_ntb_mw_get_wc),
        DEVMETHOD(ntb_mw_set_wc,        intel_ntb_mw_set_wc),
        DEVMETHOD(ntb_spad_count,       intel_ntb_spad_count),
        DEVMETHOD(ntb_spad_clear,       intel_ntb_spad_clear),
        DEVMETHOD(ntb_spad_write,       intel_ntb_spad_write),
        DEVMETHOD(ntb_spad_read,        intel_ntb_spad_read),
        DEVMETHOD(ntb_peer_spad_write,  intel_ntb_peer_spad_write),
        DEVMETHOD(ntb_peer_spad_read,   intel_ntb_peer_spad_read),
        DEVMETHOD(ntb_db_valid_mask,    intel_ntb_db_valid_mask),
        DEVMETHOD(ntb_db_vector_count,  intel_ntb_db_vector_count),
        DEVMETHOD(ntb_db_vector_mask,   intel_ntb_db_vector_mask),
        DEVMETHOD(ntb_db_clear,         intel_ntb_db_clear),
        DEVMETHOD(ntb_db_clear_mask,    intel_ntb_db_clear_mask),
        DEVMETHOD(ntb_db_read,          intel_ntb_db_read),
        DEVMETHOD(ntb_db_set_mask,      intel_ntb_db_set_mask),
        DEVMETHOD(ntb_peer_db_addr,     intel_ntb_peer_db_addr),
        DEVMETHOD(ntb_peer_db_set,      intel_ntb_peer_db_set),
        DEVMETHOD_END
};

static DEFINE_CLASS_0(ntb_hw, ntb_intel_driver, ntb_intel_methods,
    sizeof(struct ntb_softc));
DRIVER_MODULE(ntb_hw_intel, pci, ntb_intel_driver, NULL, NULL);
MODULE_DEPEND(ntb_hw_intel, ntb, 1, 1, 1);
MODULE_VERSION(ntb_hw_intel, 1);
MODULE_PNP_INFO("W32:vendor/device;D:#", pci, ntb_hw_intel, pci_ids,
    nitems(pci_ids));