root/drivers/ntb/hw/mscc/ntb_hw_switchtec.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Microsemi Switchtec(tm) PCIe Management Driver
 * Copyright (c) 2017, Microsemi Corporation
 */

#include <linux/interrupt.h>
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/ntb.h>
#include <linux/pci.h>
#include <linux/switchtec.h>

MODULE_DESCRIPTION("Microsemi Switchtec(tm) NTB Driver");
MODULE_VERSION("0.1");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Microsemi Corporation");

static ulong max_mw_size = SZ_2M;
module_param(max_mw_size, ulong, 0644);
MODULE_PARM_DESC(max_mw_size,
        "Max memory window size reported to the upper layer");

static bool use_lut_mws;
module_param(use_lut_mws, bool, 0644);
MODULE_PARM_DESC(use_lut_mws,
                 "Enable the use of the LUT based memory windows");

#define SWITCHTEC_NTB_MAGIC 0x45CC0001
#define MAX_MWS     256

struct shared_mw {
        u32 magic;
        u32 link_sta;
        u32 partition_id;
        u64 mw_sizes[MAX_MWS];
        u32 spad[128];
};

#define MAX_DIRECT_MW ARRAY_SIZE(((struct ntb_ctrl_regs *)(0))->bar_entry)
#define LUT_SIZE SZ_64K

struct switchtec_ntb {
        struct ntb_dev ntb;
        struct switchtec_dev *stdev;

        int self_partition;
        int peer_partition;

        int doorbell_irq;
        int message_irq;

        struct ntb_info_regs __iomem *mmio_ntb;
        struct ntb_ctrl_regs __iomem *mmio_ctrl;
        struct ntb_dbmsg_regs __iomem *mmio_dbmsg;
        struct ntb_ctrl_regs __iomem *mmio_self_ctrl;
        struct ntb_ctrl_regs __iomem *mmio_peer_ctrl;
        struct ntb_dbmsg_regs __iomem *mmio_self_dbmsg;
        struct ntb_dbmsg_regs __iomem *mmio_peer_dbmsg;

        void __iomem *mmio_xlink_win;

        struct shared_mw *self_shared;
        struct shared_mw __iomem *peer_shared;
        dma_addr_t self_shared_dma;

        u64 db_mask;
        u64 db_valid_mask;
        int db_shift;
        int db_peer_shift;

        /* synchronize rmw access of db_mask and hw reg */
        spinlock_t db_mask_lock;

        int nr_direct_mw;
        int nr_lut_mw;
        int nr_rsvd_luts;
        int direct_mw_to_bar[MAX_DIRECT_MW];

        int peer_nr_direct_mw;
        int peer_nr_lut_mw;
        int peer_direct_mw_to_bar[MAX_DIRECT_MW];

        bool link_is_up;
        enum ntb_speed link_speed;
        enum ntb_width link_width;
        struct work_struct check_link_status_work;
        bool link_force_down;
};

static struct switchtec_ntb *ntb_sndev(struct ntb_dev *ntb)
{
        return container_of(ntb, struct switchtec_ntb, ntb);
}

static int switchtec_ntb_part_op(struct switchtec_ntb *sndev,
                                 struct ntb_ctrl_regs __iomem *ctl,
                                 u32 op, int wait_status)
{
        static const char * const op_text[] = {
                [NTB_CTRL_PART_OP_LOCK] = "lock",
                [NTB_CTRL_PART_OP_CFG] = "configure",
                [NTB_CTRL_PART_OP_RESET] = "reset",
        };

        int i;
        u32 ps;
        int status;

        switch (op) {
        case NTB_CTRL_PART_OP_LOCK:
                status = NTB_CTRL_PART_STATUS_LOCKING;
                break;
        case NTB_CTRL_PART_OP_CFG:
                status = NTB_CTRL_PART_STATUS_CONFIGURING;
                break;
        case NTB_CTRL_PART_OP_RESET:
                status = NTB_CTRL_PART_STATUS_RESETTING;
                break;
        default:
                return -EINVAL;
        }

        iowrite32(op, &ctl->partition_op);

        for (i = 0; i < 1000; i++) {
                if (msleep_interruptible(50) != 0) {
                        iowrite32(NTB_CTRL_PART_OP_RESET, &ctl->partition_op);
                        return -EINTR;
                }

                ps = ioread32(&ctl->partition_status) & 0xFFFF;

                if (ps != status)
                        break;
        }

        if (ps == wait_status)
                return 0;

        if (ps == status) {
                dev_err(&sndev->stdev->dev,
                        "Timed out while performing %s (%d). (%08x)\n",
                        op_text[op], op,
                        ioread32(&ctl->partition_status));

                return -ETIMEDOUT;
        }

        return -EIO;
}

static int switchtec_ntb_send_msg(struct switchtec_ntb *sndev, int idx,
                                  u32 val)
{
        if (idx < 0 || idx >= ARRAY_SIZE(sndev->mmio_peer_dbmsg->omsg))
                return -EINVAL;

        iowrite32(val, &sndev->mmio_peer_dbmsg->omsg[idx].msg);

        return 0;
}

static int switchtec_ntb_mw_count(struct ntb_dev *ntb, int pidx)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);
        int nr_direct_mw = sndev->peer_nr_direct_mw;
        int nr_lut_mw = sndev->peer_nr_lut_mw - sndev->nr_rsvd_luts;

        if (pidx != NTB_DEF_PEER_IDX)
                return -EINVAL;

        if (!use_lut_mws)
                nr_lut_mw = 0;

        return nr_direct_mw + nr_lut_mw;
}

static int lut_index(struct switchtec_ntb *sndev, int mw_idx)
{
        return mw_idx - sndev->nr_direct_mw + sndev->nr_rsvd_luts;
}

static int peer_lut_index(struct switchtec_ntb *sndev, int mw_idx)
{
        return mw_idx - sndev->peer_nr_direct_mw + sndev->nr_rsvd_luts;
}

static int switchtec_ntb_mw_get_align(struct ntb_dev *ntb, int pidx,
                                      int widx, resource_size_t *addr_align,
                                      resource_size_t *size_align,
                                      resource_size_t *size_max)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);
        int lut;
        resource_size_t size;

        if (pidx != NTB_DEF_PEER_IDX)
                return -EINVAL;

        lut = widx >= sndev->peer_nr_direct_mw;
        size = ioread64(&sndev->peer_shared->mw_sizes[widx]);

        if (size == 0)
                return -EINVAL;

        if (addr_align)
                *addr_align = lut ? size : SZ_4K;

        if (size_align)
                *size_align = lut ? size : SZ_4K;

        if (size_max)
                *size_max = size;

        return 0;
}

static void switchtec_ntb_mw_clr_direct(struct switchtec_ntb *sndev, int idx)
{
        struct ntb_ctrl_regs __iomem *ctl = sndev->mmio_peer_ctrl;
        int bar = sndev->peer_direct_mw_to_bar[idx];
        u32 ctl_val;

        ctl_val = ioread32(&ctl->bar_entry[bar].ctl);
        ctl_val &= ~NTB_CTRL_BAR_DIR_WIN_EN;
        iowrite32(ctl_val, &ctl->bar_entry[bar].ctl);
        iowrite32(0, &ctl->bar_entry[bar].win_size);
        iowrite32(0, &ctl->bar_ext_entry[bar].win_size);
        iowrite64(sndev->self_partition, &ctl->bar_entry[bar].xlate_addr);
}

static void switchtec_ntb_mw_clr_lut(struct switchtec_ntb *sndev, int idx)
{
        struct ntb_ctrl_regs __iomem *ctl = sndev->mmio_peer_ctrl;

        iowrite64(0, &ctl->lut_entry[peer_lut_index(sndev, idx)]);
}

static void switchtec_ntb_mw_set_direct(struct switchtec_ntb *sndev, int idx,
                                        dma_addr_t addr, resource_size_t size)
{
        int xlate_pos = ilog2(size);
        int bar = sndev->peer_direct_mw_to_bar[idx];
        struct ntb_ctrl_regs __iomem *ctl = sndev->mmio_peer_ctrl;
        u32 ctl_val;

        ctl_val = ioread32(&ctl->bar_entry[bar].ctl);
        ctl_val |= NTB_CTRL_BAR_DIR_WIN_EN;

        iowrite32(ctl_val, &ctl->bar_entry[bar].ctl);
        iowrite32(xlate_pos | (lower_32_bits(size) & 0xFFFFF000),
                  &ctl->bar_entry[bar].win_size);
        iowrite32(upper_32_bits(size), &ctl->bar_ext_entry[bar].win_size);
        iowrite64(sndev->self_partition | addr,
                  &ctl->bar_entry[bar].xlate_addr);
}

static void switchtec_ntb_mw_set_lut(struct switchtec_ntb *sndev, int idx,
                                     dma_addr_t addr, resource_size_t size)
{
        struct ntb_ctrl_regs __iomem *ctl = sndev->mmio_peer_ctrl;

        iowrite64((NTB_CTRL_LUT_EN | (sndev->self_partition << 1) | addr),
                  &ctl->lut_entry[peer_lut_index(sndev, idx)]);
}

static int switchtec_ntb_mw_set_trans(struct ntb_dev *ntb, int pidx, int widx,
                                      dma_addr_t addr, resource_size_t size)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);
        struct ntb_ctrl_regs __iomem *ctl = sndev->mmio_peer_ctrl;
        int xlate_pos = ilog2(size);
        int nr_direct_mw = sndev->peer_nr_direct_mw;
        int rc;

        if (pidx != NTB_DEF_PEER_IDX)
                return -EINVAL;

        dev_dbg(&sndev->stdev->dev, "MW %d: part %d addr %pad size %pap\n",
                widx, pidx, &addr, &size);

        if (widx >= switchtec_ntb_mw_count(ntb, pidx))
                return -EINVAL;

        if (size != 0 && xlate_pos < 12)
                return -EINVAL;

        if (xlate_pos >= 0 && !IS_ALIGNED(addr, BIT_ULL(xlate_pos))) {
                /*
                 * In certain circumstances we can get a buffer that is
                 * not aligned to its size. (Most of the time
                 * dma_alloc_coherent ensures this). This can happen when
                 * using large buffers allocated by the CMA
                 * (see CMA_CONFIG_ALIGNMENT)
                 */
                dev_err(&sndev->stdev->dev,
                        "ERROR: Memory window address is not aligned to its size!\n");
                return -EINVAL;
        }

        rc = switchtec_ntb_part_op(sndev, ctl, NTB_CTRL_PART_OP_LOCK,
                                   NTB_CTRL_PART_STATUS_LOCKED);
        if (rc)
                return rc;

        if (size == 0) {
                if (widx < nr_direct_mw)
                        switchtec_ntb_mw_clr_direct(sndev, widx);
                else
                        switchtec_ntb_mw_clr_lut(sndev, widx);
        } else {
                if (widx < nr_direct_mw)
                        switchtec_ntb_mw_set_direct(sndev, widx, addr, size);
                else
                        switchtec_ntb_mw_set_lut(sndev, widx, addr, size);
        }

        rc = switchtec_ntb_part_op(sndev, ctl, NTB_CTRL_PART_OP_CFG,
                                   NTB_CTRL_PART_STATUS_NORMAL);

        if (rc == -EIO) {
                dev_err(&sndev->stdev->dev,
                        "Hardware reported an error configuring mw %d: %08x\n",
                        widx, ioread32(&ctl->bar_error));

                if (widx < nr_direct_mw)
                        switchtec_ntb_mw_clr_direct(sndev, widx);
                else
                        switchtec_ntb_mw_clr_lut(sndev, widx);

                switchtec_ntb_part_op(sndev, ctl, NTB_CTRL_PART_OP_CFG,
                                      NTB_CTRL_PART_STATUS_NORMAL);
        }

        return rc;
}

static int switchtec_ntb_peer_mw_count(struct ntb_dev *ntb)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);
        int nr_lut_mw = sndev->nr_lut_mw - sndev->nr_rsvd_luts;

        return sndev->nr_direct_mw + (use_lut_mws ? nr_lut_mw : 0);
}

static int switchtec_ntb_direct_get_addr(struct switchtec_ntb *sndev,
                                         int idx, phys_addr_t *base,
                                         resource_size_t *size)
{
        int bar = sndev->direct_mw_to_bar[idx];
        size_t offset = 0;

        if (bar < 0)
                return -EINVAL;

        if (idx == 0) {
                /*
                 * This is the direct BAR shared with the LUTs
                 * which means the actual window will be offset
                 * by the size of all the LUT entries.
                 */

                offset = LUT_SIZE * sndev->nr_lut_mw;
        }

        if (base)
                *base = pci_resource_start(sndev->ntb.pdev, bar) + offset;

        if (size) {
                *size = pci_resource_len(sndev->ntb.pdev, bar) - offset;
                if (offset && *size > offset)
                        *size = offset;

                if (*size > max_mw_size)
                        *size = max_mw_size;
        }

        return 0;
}

static int switchtec_ntb_lut_get_addr(struct switchtec_ntb *sndev,
                                      int idx, phys_addr_t *base,
                                      resource_size_t *size)
{
        int bar = sndev->direct_mw_to_bar[0];
        int offset;

        offset = LUT_SIZE * lut_index(sndev, idx);

        if (base)
                *base = pci_resource_start(sndev->ntb.pdev, bar) + offset;

        if (size)
                *size = LUT_SIZE;

        return 0;
}

static int switchtec_ntb_peer_mw_get_addr(struct ntb_dev *ntb, int idx,
                                          phys_addr_t *base,
                                          resource_size_t *size)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);

        if (idx < sndev->nr_direct_mw)
                return switchtec_ntb_direct_get_addr(sndev, idx, base, size);
        else if (idx < switchtec_ntb_peer_mw_count(ntb))
                return switchtec_ntb_lut_get_addr(sndev, idx, base, size);
        else
                return -EINVAL;
}

static void switchtec_ntb_part_link_speed(struct switchtec_ntb *sndev,
                                          int partition,
                                          enum ntb_speed *speed,
                                          enum ntb_width *width)
{
        struct switchtec_dev *stdev = sndev->stdev;
        struct part_cfg_regs __iomem *part_cfg =
                &stdev->mmio_part_cfg_all[partition];

        u32 pff = ioread32(&part_cfg->vep_pff_inst_id) & 0xFF;
        u32 linksta = ioread32(&stdev->mmio_pff_csr[pff].pci_cap_region[13]);

        if (speed)
                *speed = (linksta >> 16) & 0xF;

        if (width)
                *width = (linksta >> 20) & 0x3F;
}

static void switchtec_ntb_set_link_speed(struct switchtec_ntb *sndev)
{
        enum ntb_speed self_speed, peer_speed;
        enum ntb_width self_width, peer_width;

        if (!sndev->link_is_up) {
                sndev->link_speed = NTB_SPEED_NONE;
                sndev->link_width = NTB_WIDTH_NONE;
                return;
        }

        switchtec_ntb_part_link_speed(sndev, sndev->self_partition,
                                      &self_speed, &self_width);
        switchtec_ntb_part_link_speed(sndev, sndev->peer_partition,
                                      &peer_speed, &peer_width);

        sndev->link_speed = min(self_speed, peer_speed);
        sndev->link_width = min(self_width, peer_width);
}

static int crosslink_is_enabled(struct switchtec_ntb *sndev)
{
        struct ntb_info_regs __iomem *inf = sndev->mmio_ntb;

        return ioread8(&inf->ntp_info[sndev->peer_partition].xlink_enabled);
}

static void crosslink_init_dbmsgs(struct switchtec_ntb *sndev)
{
        int i;
        u32 msg_map = 0;

        if (!crosslink_is_enabled(sndev))
                return;

        for (i = 0; i < ARRAY_SIZE(sndev->mmio_peer_dbmsg->imsg); i++) {
                int m = i | sndev->self_partition << 2;

                msg_map |= m << i * 8;
        }

        iowrite32(msg_map, &sndev->mmio_peer_dbmsg->msg_map);
        iowrite64(sndev->db_valid_mask << sndev->db_peer_shift,
                  &sndev->mmio_peer_dbmsg->odb_mask);
}

enum switchtec_msg {
        LINK_MESSAGE = 0,
        MSG_LINK_UP = 1,
        MSG_LINK_DOWN = 2,
        MSG_CHECK_LINK = 3,
        MSG_LINK_FORCE_DOWN = 4,
};

static int switchtec_ntb_reinit_peer(struct switchtec_ntb *sndev);

static void switchtec_ntb_link_status_update(struct switchtec_ntb *sndev)
{
        int link_sta;
        int old = sndev->link_is_up;

        link_sta = sndev->self_shared->link_sta;
        if (link_sta) {
                u64 peer = ioread64(&sndev->peer_shared->magic);

                if ((peer & 0xFFFFFFFF) == SWITCHTEC_NTB_MAGIC)
                        link_sta = peer >> 32;
                else
                        link_sta = 0;
        }

        sndev->link_is_up = link_sta;
        switchtec_ntb_set_link_speed(sndev);

        if (link_sta != old) {
                switchtec_ntb_send_msg(sndev, LINK_MESSAGE, MSG_CHECK_LINK);
                ntb_link_event(&sndev->ntb);
                dev_info(&sndev->stdev->dev, "ntb link %s\n",
                         link_sta ? "up" : "down");

                if (link_sta)
                        crosslink_init_dbmsgs(sndev);
        }
}

static void check_link_status_work(struct work_struct *work)
{
        struct switchtec_ntb *sndev;

        sndev = container_of(work, struct switchtec_ntb,
                             check_link_status_work);

        if (sndev->link_force_down) {
                sndev->link_force_down = false;
                switchtec_ntb_reinit_peer(sndev);

                if (sndev->link_is_up) {
                        sndev->link_is_up = 0;
                        ntb_link_event(&sndev->ntb);
                        dev_info(&sndev->stdev->dev, "ntb link forced down\n");
                }

                return;
        }

        switchtec_ntb_link_status_update(sndev);
}

static void switchtec_ntb_check_link(struct switchtec_ntb *sndev,
                                      enum switchtec_msg msg)
{
        if (msg == MSG_LINK_FORCE_DOWN)
                sndev->link_force_down = true;

        schedule_work(&sndev->check_link_status_work);
}

static void switchtec_ntb_link_notification(struct switchtec_dev *stdev)
{
        struct switchtec_ntb *sndev = stdev->sndev;

        switchtec_ntb_check_link(sndev, MSG_CHECK_LINK);
}

static u64 switchtec_ntb_link_is_up(struct ntb_dev *ntb,
                                    enum ntb_speed *speed,
                                    enum ntb_width *width)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);

        if (speed)
                *speed = sndev->link_speed;
        if (width)
                *width = sndev->link_width;

        return sndev->link_is_up;
}

static int switchtec_ntb_link_enable(struct ntb_dev *ntb,
                                     enum ntb_speed max_speed,
                                     enum ntb_width max_width)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);

        dev_dbg(&sndev->stdev->dev, "enabling link\n");

        sndev->self_shared->link_sta = 1;
        switchtec_ntb_send_msg(sndev, LINK_MESSAGE, MSG_LINK_UP);

        switchtec_ntb_link_status_update(sndev);

        return 0;
}

static int switchtec_ntb_link_disable(struct ntb_dev *ntb)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);

        dev_dbg(&sndev->stdev->dev, "disabling link\n");

        sndev->self_shared->link_sta = 0;
        switchtec_ntb_send_msg(sndev, LINK_MESSAGE, MSG_LINK_DOWN);

        switchtec_ntb_link_status_update(sndev);

        return 0;
}

static u64 switchtec_ntb_db_valid_mask(struct ntb_dev *ntb)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);

        return sndev->db_valid_mask;
}

static int switchtec_ntb_db_vector_count(struct ntb_dev *ntb)
{
        return 1;
}

static u64 switchtec_ntb_db_vector_mask(struct ntb_dev *ntb, int db_vector)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);

        if (db_vector < 0 || db_vector > 1)
                return 0;

        return sndev->db_valid_mask;
}

static u64 switchtec_ntb_db_read(struct ntb_dev *ntb)
{
        u64 ret;
        struct switchtec_ntb *sndev = ntb_sndev(ntb);

        ret = ioread64(&sndev->mmio_self_dbmsg->idb) >> sndev->db_shift;

        return ret & sndev->db_valid_mask;
}

static int switchtec_ntb_db_clear(struct ntb_dev *ntb, u64 db_bits)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);

        iowrite64(db_bits << sndev->db_shift, &sndev->mmio_self_dbmsg->idb);

        return 0;
}

static int switchtec_ntb_db_set_mask(struct ntb_dev *ntb, u64 db_bits)
{
        unsigned long irqflags;
        struct switchtec_ntb *sndev = ntb_sndev(ntb);

        if (db_bits & ~sndev->db_valid_mask)
                return -EINVAL;

        spin_lock_irqsave(&sndev->db_mask_lock, irqflags);

        sndev->db_mask |= db_bits << sndev->db_shift;
        iowrite64(~sndev->db_mask, &sndev->mmio_self_dbmsg->idb_mask);

        spin_unlock_irqrestore(&sndev->db_mask_lock, irqflags);

        return 0;
}

static int switchtec_ntb_db_clear_mask(struct ntb_dev *ntb, u64 db_bits)
{
        unsigned long irqflags;
        struct switchtec_ntb *sndev = ntb_sndev(ntb);

        if (db_bits & ~sndev->db_valid_mask)
                return -EINVAL;

        spin_lock_irqsave(&sndev->db_mask_lock, irqflags);

        sndev->db_mask &= ~(db_bits << sndev->db_shift);
        iowrite64(~sndev->db_mask, &sndev->mmio_self_dbmsg->idb_mask);

        spin_unlock_irqrestore(&sndev->db_mask_lock, irqflags);

        return 0;
}

static u64 switchtec_ntb_db_read_mask(struct ntb_dev *ntb)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);

        return (sndev->db_mask >> sndev->db_shift) & sndev->db_valid_mask;
}

static int switchtec_ntb_peer_db_addr(struct ntb_dev *ntb,
                                      phys_addr_t *db_addr,
                                      resource_size_t *db_size,
                                      u64 *db_data,
                                      int db_bit)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);
        unsigned long offset;

        if (unlikely(db_bit >= BITS_PER_LONG_LONG))
                return -EINVAL;

        offset = (unsigned long)sndev->mmio_peer_dbmsg->odb -
                (unsigned long)sndev->stdev->mmio;

        offset += sndev->db_shift / 8;

        if (db_addr)
                *db_addr = pci_resource_start(ntb->pdev, 0) + offset;
        if (db_size)
                *db_size = sizeof(u32);
        if (db_data)
                *db_data = BIT_ULL(db_bit) << sndev->db_peer_shift;

        return 0;
}

static int switchtec_ntb_peer_db_set(struct ntb_dev *ntb, u64 db_bits)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);

        iowrite64(db_bits << sndev->db_peer_shift,
                  &sndev->mmio_peer_dbmsg->odb);

        return 0;
}

static int switchtec_ntb_spad_count(struct ntb_dev *ntb)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);

        return ARRAY_SIZE(sndev->self_shared->spad);
}

static u32 switchtec_ntb_spad_read(struct ntb_dev *ntb, int idx)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);

        if (idx < 0 || idx >= ARRAY_SIZE(sndev->self_shared->spad))
                return 0;

        if (!sndev->self_shared)
                return 0;

        return sndev->self_shared->spad[idx];
}

static int switchtec_ntb_spad_write(struct ntb_dev *ntb, int idx, u32 val)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);

        if (idx < 0 || idx >= ARRAY_SIZE(sndev->self_shared->spad))
                return -EINVAL;

        if (!sndev->self_shared)
                return -EIO;

        sndev->self_shared->spad[idx] = val;

        return 0;
}

static u32 switchtec_ntb_peer_spad_read(struct ntb_dev *ntb, int pidx,
                                        int sidx)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);

        if (pidx != NTB_DEF_PEER_IDX)
                return -EINVAL;

        if (sidx < 0 || sidx >= ARRAY_SIZE(sndev->peer_shared->spad))
                return 0;

        if (!sndev->peer_shared)
                return 0;

        return ioread32(&sndev->peer_shared->spad[sidx]);
}

static int switchtec_ntb_peer_spad_write(struct ntb_dev *ntb, int pidx,
                                         int sidx, u32 val)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);

        if (pidx != NTB_DEF_PEER_IDX)
                return -EINVAL;

        if (sidx < 0 || sidx >= ARRAY_SIZE(sndev->peer_shared->spad))
                return -EINVAL;

        if (!sndev->peer_shared)
                return -EIO;

        iowrite32(val, &sndev->peer_shared->spad[sidx]);

        return 0;
}

static int switchtec_ntb_peer_spad_addr(struct ntb_dev *ntb, int pidx,
                                        int sidx, phys_addr_t *spad_addr)
{
        struct switchtec_ntb *sndev = ntb_sndev(ntb);
        unsigned long offset;

        if (pidx != NTB_DEF_PEER_IDX)
                return -EINVAL;

        offset = (unsigned long)&sndev->peer_shared->spad[sidx] -
                (unsigned long)sndev->stdev->mmio;

        if (spad_addr)
                *spad_addr = pci_resource_start(ntb->pdev, 0) + offset;

        return 0;
}

static const struct ntb_dev_ops switchtec_ntb_ops = {
        .mw_count               = switchtec_ntb_mw_count,
        .mw_get_align           = switchtec_ntb_mw_get_align,
        .mw_set_trans           = switchtec_ntb_mw_set_trans,
        .peer_mw_count          = switchtec_ntb_peer_mw_count,
        .peer_mw_get_addr       = switchtec_ntb_peer_mw_get_addr,
        .link_is_up             = switchtec_ntb_link_is_up,
        .link_enable            = switchtec_ntb_link_enable,
        .link_disable           = switchtec_ntb_link_disable,
        .db_valid_mask          = switchtec_ntb_db_valid_mask,
        .db_vector_count        = switchtec_ntb_db_vector_count,
        .db_vector_mask         = switchtec_ntb_db_vector_mask,
        .db_read                = switchtec_ntb_db_read,
        .db_clear               = switchtec_ntb_db_clear,
        .db_set_mask            = switchtec_ntb_db_set_mask,
        .db_clear_mask          = switchtec_ntb_db_clear_mask,
        .db_read_mask           = switchtec_ntb_db_read_mask,
        .peer_db_addr           = switchtec_ntb_peer_db_addr,
        .peer_db_set            = switchtec_ntb_peer_db_set,
        .spad_count             = switchtec_ntb_spad_count,
        .spad_read              = switchtec_ntb_spad_read,
        .spad_write             = switchtec_ntb_spad_write,
        .peer_spad_read         = switchtec_ntb_peer_spad_read,
        .peer_spad_write        = switchtec_ntb_peer_spad_write,
        .peer_spad_addr         = switchtec_ntb_peer_spad_addr,
};

static int switchtec_ntb_init_sndev(struct switchtec_ntb *sndev)
{
        u64 tpart_vec;
        int self;
        u64 part_map;

        sndev->ntb.pdev = sndev->stdev->pdev;
        sndev->ntb.topo = NTB_TOPO_SWITCH;
        sndev->ntb.ops = &switchtec_ntb_ops;

        INIT_WORK(&sndev->check_link_status_work, check_link_status_work);
        sndev->link_force_down = false;

        sndev->self_partition = sndev->stdev->partition;

        sndev->mmio_ntb = sndev->stdev->mmio_ntb;

        self = sndev->self_partition;
        tpart_vec = ioread32(&sndev->mmio_ntb->ntp_info[self].target_part_high);
        tpart_vec <<= 32;
        tpart_vec |= ioread32(&sndev->mmio_ntb->ntp_info[self].target_part_low);

        part_map = ioread64(&sndev->mmio_ntb->ep_map);
        tpart_vec &= part_map;
        part_map &= ~(1 << sndev->self_partition);

        if (!tpart_vec) {
                if (sndev->stdev->partition_count != 2) {
                        dev_err(&sndev->stdev->dev,
                                "ntb target partition not defined\n");
                        return -ENODEV;
                }

                if (!part_map) {
                        dev_err(&sndev->stdev->dev,
                                "peer partition is not NT partition\n");
                        return -ENODEV;
                }

                sndev->peer_partition = __ffs64(part_map);
        } else {
                if (__ffs64(tpart_vec) != (fls64(tpart_vec) - 1)) {
                        dev_err(&sndev->stdev->dev,
                                "ntb driver only supports 1 pair of 1-1 ntb mapping\n");
                        return -ENODEV;
                }

                sndev->peer_partition = __ffs64(tpart_vec);
                if (!(part_map & (1ULL << sndev->peer_partition))) {
                        dev_err(&sndev->stdev->dev,
                                "ntb target partition is not NT partition\n");
                        return -ENODEV;
                }
        }

        dev_dbg(&sndev->stdev->dev, "Partition ID %d of %d\n",
                sndev->self_partition, sndev->stdev->partition_count);

        sndev->mmio_ctrl = (void * __iomem)sndev->mmio_ntb +
                SWITCHTEC_NTB_REG_CTRL_OFFSET;
        sndev->mmio_dbmsg = (void * __iomem)sndev->mmio_ntb +
                SWITCHTEC_NTB_REG_DBMSG_OFFSET;

        sndev->mmio_self_ctrl = &sndev->mmio_ctrl[sndev->self_partition];
        sndev->mmio_peer_ctrl = &sndev->mmio_ctrl[sndev->peer_partition];
        sndev->mmio_self_dbmsg = &sndev->mmio_dbmsg[sndev->self_partition];
        sndev->mmio_peer_dbmsg = sndev->mmio_self_dbmsg;

        return 0;
}

static int config_rsvd_lut_win(struct switchtec_ntb *sndev,
                               struct ntb_ctrl_regs __iomem *ctl,
                               int lut_idx, int partition, u64 addr)
{
        int peer_bar = sndev->peer_direct_mw_to_bar[0];
        u32 ctl_val;
        int rc;

        rc = switchtec_ntb_part_op(sndev, ctl, NTB_CTRL_PART_OP_LOCK,
                                   NTB_CTRL_PART_STATUS_LOCKED);
        if (rc)
                return rc;

        ctl_val = ioread32(&ctl->bar_entry[peer_bar].ctl);
        ctl_val &= 0xFF;
        ctl_val |= NTB_CTRL_BAR_LUT_WIN_EN;
        ctl_val |= ilog2(LUT_SIZE) << 8;
        ctl_val |= (sndev->nr_lut_mw - 1) << 14;
        iowrite32(ctl_val, &ctl->bar_entry[peer_bar].ctl);

        iowrite64((NTB_CTRL_LUT_EN | (partition << 1) | addr),
                  &ctl->lut_entry[lut_idx]);

        rc = switchtec_ntb_part_op(sndev, ctl, NTB_CTRL_PART_OP_CFG,
                                   NTB_CTRL_PART_STATUS_NORMAL);
        if (rc) {
                u32 bar_error, lut_error;

                bar_error = ioread32(&ctl->bar_error);
                lut_error = ioread32(&ctl->lut_error);
                dev_err(&sndev->stdev->dev,
                        "Error setting up reserved lut window: %08x / %08x\n",
                        bar_error, lut_error);
                return rc;
        }

        return 0;
}

static int config_req_id_table(struct switchtec_ntb *sndev,
                               struct ntb_ctrl_regs __iomem *mmio_ctrl,
                               int *req_ids, int count)
{
        int i, rc = 0;
        u32 error;
        u32 proxy_id;

        if (ioread16(&mmio_ctrl->req_id_table_size) < count) {
                dev_err(&sndev->stdev->dev,
                        "Not enough requester IDs available.\n");
                return -EFAULT;
        }

        rc = switchtec_ntb_part_op(sndev, mmio_ctrl,
                                   NTB_CTRL_PART_OP_LOCK,
                                   NTB_CTRL_PART_STATUS_LOCKED);
        if (rc)
                return rc;

        for (i = 0; i < count; i++) {
                iowrite32(req_ids[i] << 16 | NTB_CTRL_REQ_ID_EN,
                          &mmio_ctrl->req_id_table[i]);

                proxy_id = ioread32(&mmio_ctrl->req_id_table[i]);
                dev_dbg(&sndev->stdev->dev,
                        "Requester ID %02X:%02X.%X -> BB:%02X.%X\n",
                        req_ids[i] >> 8, (req_ids[i] >> 3) & 0x1F,
                        req_ids[i] & 0x7, (proxy_id >> 4) & 0x1F,
                        (proxy_id >> 1) & 0x7);
        }

        rc = switchtec_ntb_part_op(sndev, mmio_ctrl,
                                   NTB_CTRL_PART_OP_CFG,
                                   NTB_CTRL_PART_STATUS_NORMAL);

        if (rc == -EIO) {
                error = ioread32(&mmio_ctrl->req_id_error);
                dev_err(&sndev->stdev->dev,
                        "Error setting up the requester ID table: %08x\n",
                        error);
        }

        return 0;
}

static int crosslink_setup_mws(struct switchtec_ntb *sndev, int ntb_lut_idx,
                               u64 *mw_addrs, int mw_count)
{
        int rc, i;
        struct ntb_ctrl_regs __iomem *ctl = sndev->mmio_self_ctrl;
        u64 addr;
        size_t size, offset;
        int bar;
        int xlate_pos;
        u32 ctl_val;

        rc = switchtec_ntb_part_op(sndev, ctl, NTB_CTRL_PART_OP_LOCK,
                                   NTB_CTRL_PART_STATUS_LOCKED);
        if (rc)
                return rc;

        for (i = 0; i < sndev->nr_lut_mw; i++) {
                if (i == ntb_lut_idx)
                        continue;

                addr = mw_addrs[0] + LUT_SIZE * i;

                iowrite64((NTB_CTRL_LUT_EN | (sndev->peer_partition << 1) |
                           addr),
                          &ctl->lut_entry[i]);
        }

        sndev->nr_direct_mw = min_t(int, sndev->nr_direct_mw, mw_count);

        for (i = 0; i < sndev->nr_direct_mw; i++) {
                bar = sndev->direct_mw_to_bar[i];
                offset = (i == 0) ? LUT_SIZE * sndev->nr_lut_mw : 0;
                addr = mw_addrs[i] + offset;
                size = pci_resource_len(sndev->ntb.pdev, bar) - offset;
                xlate_pos = ilog2(size);

                if (offset && size > offset)
                        size = offset;

                ctl_val = ioread32(&ctl->bar_entry[bar].ctl);
                ctl_val |= NTB_CTRL_BAR_DIR_WIN_EN;

                iowrite32(ctl_val, &ctl->bar_entry[bar].ctl);
                iowrite32(xlate_pos | (lower_32_bits(size) & 0xFFFFF000),
                          &ctl->bar_entry[bar].win_size);
                iowrite32(upper_32_bits(size), &ctl->bar_ext_entry[bar].win_size);
                iowrite64(sndev->peer_partition | addr,
                          &ctl->bar_entry[bar].xlate_addr);
        }

        rc = switchtec_ntb_part_op(sndev, ctl, NTB_CTRL_PART_OP_CFG,
                                   NTB_CTRL_PART_STATUS_NORMAL);
        if (rc) {
                u32 bar_error, lut_error;

                bar_error = ioread32(&ctl->bar_error);
                lut_error = ioread32(&ctl->lut_error);
                dev_err(&sndev->stdev->dev,
                        "Error setting up cross link windows: %08x / %08x\n",
                        bar_error, lut_error);
                return rc;
        }

        return 0;
}

static int crosslink_setup_req_ids(struct switchtec_ntb *sndev,
        struct ntb_ctrl_regs __iomem *mmio_ctrl)
{
        int req_ids[16];
        int i;
        u32 proxy_id;

        for (i = 0; i < ARRAY_SIZE(req_ids); i++) {
                proxy_id = ioread32(&sndev->mmio_self_ctrl->req_id_table[i]);

                if (!(proxy_id & NTB_CTRL_REQ_ID_EN))
                        break;

                req_ids[i] = ((proxy_id >> 1) & 0xFF);
        }

        return config_req_id_table(sndev, mmio_ctrl, req_ids, i);
}

/*
 * In crosslink configuration there is a virtual partition in the
 * middle of the two switches. The BARs in this partition have to be
 * enumerated and assigned addresses.
 */
static int crosslink_enum_partition(struct switchtec_ntb *sndev,
                                    u64 *bar_addrs)
{
        struct part_cfg_regs __iomem *part_cfg =
                &sndev->stdev->mmio_part_cfg_all[sndev->peer_partition];
        u32 pff = ioread32(&part_cfg->vep_pff_inst_id) & 0xFF;
        struct pff_csr_regs __iomem *mmio_pff =
                &sndev->stdev->mmio_pff_csr[pff];
        const u64 bar_space = 0x1000000000LL;
        u64 bar_addr;
        int bar_cnt = 0;
        int i;

        iowrite16(0x6, &mmio_pff->pcicmd);

        for (i = 0; i < ARRAY_SIZE(mmio_pff->pci_bar64); i++) {
                iowrite64(bar_space * i, &mmio_pff->pci_bar64[i]);
                bar_addr = ioread64(&mmio_pff->pci_bar64[i]);
                bar_addr &= ~0xf;

                dev_dbg(&sndev->stdev->dev,
                        "Crosslink BAR%d addr: %llx\n",
                        i*2, bar_addr);

                if (bar_addr != bar_space * i)
                        continue;

                bar_addrs[bar_cnt++] = bar_addr;
        }

        return bar_cnt;
}

static int switchtec_ntb_init_crosslink(struct switchtec_ntb *sndev)
{
        int rc;
        int bar = sndev->direct_mw_to_bar[0];
        const int ntb_lut_idx = 1;
        u64 bar_addrs[6];
        u64 addr;
        int offset;
        int bar_cnt;

        if (!crosslink_is_enabled(sndev))
                return 0;

        dev_info(&sndev->stdev->dev, "Using crosslink configuration\n");
        sndev->ntb.topo = NTB_TOPO_CROSSLINK;

        bar_cnt = crosslink_enum_partition(sndev, bar_addrs);
        if (bar_cnt < sndev->nr_direct_mw + 1) {
                dev_err(&sndev->stdev->dev,
                        "Error enumerating crosslink partition\n");
                return -EINVAL;
        }

        addr = (bar_addrs[0] + SWITCHTEC_GAS_NTB_OFFSET +
                SWITCHTEC_NTB_REG_DBMSG_OFFSET +
                sizeof(struct ntb_dbmsg_regs) * sndev->peer_partition);

        offset = addr & (LUT_SIZE - 1);
        addr -= offset;

        rc = config_rsvd_lut_win(sndev, sndev->mmio_self_ctrl, ntb_lut_idx,
                                 sndev->peer_partition, addr);
        if (rc)
                return rc;

        rc = crosslink_setup_mws(sndev, ntb_lut_idx, &bar_addrs[1],
                                 bar_cnt - 1);
        if (rc)
                return rc;

        rc = crosslink_setup_req_ids(sndev, sndev->mmio_peer_ctrl);
        if (rc)
                return rc;

        sndev->mmio_xlink_win = pci_iomap_range(sndev->stdev->pdev, bar,
                                                LUT_SIZE, LUT_SIZE);
        if (!sndev->mmio_xlink_win) {
                rc = -ENOMEM;
                return rc;
        }

        sndev->mmio_peer_dbmsg = sndev->mmio_xlink_win + offset;
        sndev->nr_rsvd_luts++;

        crosslink_init_dbmsgs(sndev);

        return 0;
}

static void switchtec_ntb_deinit_crosslink(struct switchtec_ntb *sndev)
{
        if (sndev->mmio_xlink_win)
                pci_iounmap(sndev->stdev->pdev, sndev->mmio_xlink_win);
}

static int map_bars(int *map, struct ntb_ctrl_regs __iomem *ctrl)
{
        int i;
        int cnt = 0;

        for (i = 0; i < ARRAY_SIZE(ctrl->bar_entry); i++) {
                u32 r = ioread32(&ctrl->bar_entry[i].ctl);

                if (r & NTB_CTRL_BAR_VALID)
                        map[cnt++] = i;
        }

        return cnt;
}

static void switchtec_ntb_init_mw(struct switchtec_ntb *sndev)
{
        sndev->nr_direct_mw = map_bars(sndev->direct_mw_to_bar,
                                       sndev->mmio_self_ctrl);

        sndev->nr_lut_mw = ioread16(&sndev->mmio_self_ctrl->lut_table_entries);
        if (sndev->nr_lut_mw)
                sndev->nr_lut_mw = rounddown_pow_of_two(sndev->nr_lut_mw);

        dev_dbg(&sndev->stdev->dev, "MWs: %d direct, %d lut\n",
                sndev->nr_direct_mw, sndev->nr_lut_mw);

        sndev->peer_nr_direct_mw = map_bars(sndev->peer_direct_mw_to_bar,
                                            sndev->mmio_peer_ctrl);

        sndev->peer_nr_lut_mw =
                ioread16(&sndev->mmio_peer_ctrl->lut_table_entries);
        if (sndev->peer_nr_lut_mw)
                sndev->peer_nr_lut_mw = rounddown_pow_of_two(sndev->peer_nr_lut_mw);

        dev_dbg(&sndev->stdev->dev, "Peer MWs: %d direct, %d lut\n",
                sndev->peer_nr_direct_mw, sndev->peer_nr_lut_mw);

}

/*
 * There are 64 doorbells in the switch hardware but this is
 * shared among all partitions. So we must split them in half
 * (32 for each partition). However, the message interrupts are
 * also shared with the top 4 doorbells so we just limit this to
 * 28 doorbells per partition.
 *
 * In crosslink mode, each side has it's own dbmsg register so
 * they can each use all 60 of the available doorbells.
 */
static void switchtec_ntb_init_db(struct switchtec_ntb *sndev)
{
        sndev->db_mask = 0x0FFFFFFFFFFFFFFFULL;

        if (sndev->mmio_peer_dbmsg != sndev->mmio_self_dbmsg) {
                sndev->db_shift = 0;
                sndev->db_peer_shift = 0;
                sndev->db_valid_mask = sndev->db_mask;
        } else if (sndev->self_partition < sndev->peer_partition) {
                sndev->db_shift = 0;
                sndev->db_peer_shift = 32;
                sndev->db_valid_mask = 0x0FFFFFFF;
        } else {
                sndev->db_shift = 32;
                sndev->db_peer_shift = 0;
                sndev->db_valid_mask = 0x0FFFFFFF;
        }

        iowrite64(~sndev->db_mask, &sndev->mmio_self_dbmsg->idb_mask);
        iowrite64(sndev->db_valid_mask << sndev->db_peer_shift,
                  &sndev->mmio_peer_dbmsg->odb_mask);

        dev_dbg(&sndev->stdev->dev, "dbs: shift %d/%d, mask %016llx\n",
                sndev->db_shift, sndev->db_peer_shift, sndev->db_valid_mask);
}

static void switchtec_ntb_init_msgs(struct switchtec_ntb *sndev)
{
        int i;
        u32 msg_map = 0;

        for (i = 0; i < ARRAY_SIZE(sndev->mmio_self_dbmsg->imsg); i++) {
                int m = i | sndev->peer_partition << 2;

                msg_map |= m << i * 8;
        }

        iowrite32(msg_map, &sndev->mmio_self_dbmsg->msg_map);

        for (i = 0; i < ARRAY_SIZE(sndev->mmio_self_dbmsg->imsg); i++)
                iowrite64(NTB_DBMSG_IMSG_STATUS | NTB_DBMSG_IMSG_MASK,
                          &sndev->mmio_self_dbmsg->imsg[i]);
}

static int
switchtec_ntb_init_req_id_table(struct switchtec_ntb *sndev)
{
        int req_ids[2];

        /*
         * Root Complex Requester ID (which is 0:00.0)
         */
        req_ids[0] = 0;

        /*
         * Host Bridge Requester ID (as read from the mmap address)
         */
        req_ids[1] = ioread16(&sndev->mmio_ntb->requester_id);

        return config_req_id_table(sndev, sndev->mmio_self_ctrl, req_ids,
                                   ARRAY_SIZE(req_ids));
}

static void switchtec_ntb_init_shared(struct switchtec_ntb *sndev)
{
        int i;

        memset(sndev->self_shared, 0, LUT_SIZE);
        sndev->self_shared->magic = SWITCHTEC_NTB_MAGIC;
        sndev->self_shared->partition_id = sndev->stdev->partition;

        for (i = 0; i < sndev->nr_direct_mw; i++) {
                int bar = sndev->direct_mw_to_bar[i];
                resource_size_t sz = pci_resource_len(sndev->stdev->pdev, bar);

                if (i == 0)
                        sz = min_t(resource_size_t, sz,
                                   LUT_SIZE * sndev->nr_lut_mw);

                sndev->self_shared->mw_sizes[i] = sz;
        }

        for (i = 0; i < sndev->nr_lut_mw; i++) {
                int idx = sndev->nr_direct_mw + i;

                if (idx >= MAX_MWS) {
                        dev_err(&sndev->stdev->dev,
                                "Total number of MW cannot be bigger than %d", MAX_MWS);
                        break;
                }

                sndev->self_shared->mw_sizes[idx] = LUT_SIZE;
        }
}

static int switchtec_ntb_init_shared_mw(struct switchtec_ntb *sndev)
{
        int self_bar = sndev->direct_mw_to_bar[0];
        int rc;

        sndev->nr_rsvd_luts++;
        sndev->self_shared = dma_alloc_coherent(&sndev->stdev->pdev->dev,
                                                LUT_SIZE,
                                                &sndev->self_shared_dma,
                                                GFP_KERNEL);
        if (!sndev->self_shared) {
                dev_err(&sndev->stdev->dev,
                        "unable to allocate memory for shared mw\n");
                return -ENOMEM;
        }

        switchtec_ntb_init_shared(sndev);

        rc = config_rsvd_lut_win(sndev, sndev->mmio_peer_ctrl, 0,
                                 sndev->self_partition,
                                 sndev->self_shared_dma);
        if (rc)
                goto unalloc_and_exit;

        sndev->peer_shared = pci_iomap(sndev->stdev->pdev, self_bar, LUT_SIZE);
        if (!sndev->peer_shared) {
                rc = -ENOMEM;
                goto unalloc_and_exit;
        }

        dev_dbg(&sndev->stdev->dev, "Shared MW Ready\n");
        return 0;

unalloc_and_exit:
        dma_free_coherent(&sndev->stdev->pdev->dev, LUT_SIZE,
                          sndev->self_shared, sndev->self_shared_dma);

        return rc;
}

static void switchtec_ntb_deinit_shared_mw(struct switchtec_ntb *sndev)
{
        if (sndev->peer_shared)
                pci_iounmap(sndev->stdev->pdev, sndev->peer_shared);

        if (sndev->self_shared)
                dma_free_coherent(&sndev->stdev->pdev->dev, LUT_SIZE,
                                  sndev->self_shared,
                                  sndev->self_shared_dma);
        sndev->nr_rsvd_luts--;
}

static irqreturn_t switchtec_ntb_doorbell_isr(int irq, void *dev)
{
        struct switchtec_ntb *sndev = dev;

        dev_dbg(&sndev->stdev->dev, "doorbell\n");

        ntb_db_event(&sndev->ntb, 0);

        return IRQ_HANDLED;
}

static irqreturn_t switchtec_ntb_message_isr(int irq, void *dev)
{
        int i;
        struct switchtec_ntb *sndev = dev;

        for (i = 0; i < ARRAY_SIZE(sndev->mmio_self_dbmsg->imsg); i++) {
                u64 msg = ioread64(&sndev->mmio_self_dbmsg->imsg[i]);

                if (msg & NTB_DBMSG_IMSG_STATUS) {
                        dev_dbg(&sndev->stdev->dev, "message: %d %08x\n",
                                i, (u32)msg);
                        iowrite8(1, &sndev->mmio_self_dbmsg->imsg[i].status);

                        if (i == LINK_MESSAGE)
                                switchtec_ntb_check_link(sndev, msg);
                }
        }

        return IRQ_HANDLED;
}

static int switchtec_ntb_init_db_msg_irq(struct switchtec_ntb *sndev)
{
        int i;
        int rc;
        int doorbell_irq = 0;
        int message_irq = 0;
        int event_irq;
        int idb_vecs = sizeof(sndev->mmio_self_dbmsg->idb_vec_map);

        event_irq = ioread32(&sndev->stdev->mmio_part_cfg->vep_vector_number);

        while (doorbell_irq == event_irq)
                doorbell_irq++;
        while (message_irq == doorbell_irq ||
               message_irq == event_irq)
                message_irq++;

        dev_dbg(&sndev->stdev->dev, "irqs - event: %d, db: %d, msgs: %d\n",
                event_irq, doorbell_irq, message_irq);

        for (i = 0; i < idb_vecs - 4; i++)
                iowrite8(doorbell_irq,
                         &sndev->mmio_self_dbmsg->idb_vec_map[i]);

        for (; i < idb_vecs; i++)
                iowrite8(message_irq,
                         &sndev->mmio_self_dbmsg->idb_vec_map[i]);

        sndev->doorbell_irq = pci_irq_vector(sndev->stdev->pdev, doorbell_irq);
        sndev->message_irq = pci_irq_vector(sndev->stdev->pdev, message_irq);

        rc = request_irq(sndev->doorbell_irq,
                         switchtec_ntb_doorbell_isr, 0,
                         "switchtec_ntb_doorbell", sndev);
        if (rc)
                return rc;

        rc = request_irq(sndev->message_irq,
                         switchtec_ntb_message_isr, 0,
                         "switchtec_ntb_message", sndev);
        if (rc) {
                free_irq(sndev->doorbell_irq, sndev);
                return rc;
        }

        return 0;
}

static void switchtec_ntb_deinit_db_msg_irq(struct switchtec_ntb *sndev)
{
        free_irq(sndev->doorbell_irq, sndev);
        free_irq(sndev->message_irq, sndev);
}

static int switchtec_ntb_reinit_peer(struct switchtec_ntb *sndev)
{
        int rc;

        if (crosslink_is_enabled(sndev))
                return 0;

        dev_info(&sndev->stdev->dev, "reinitialize shared memory window\n");
        rc = config_rsvd_lut_win(sndev, sndev->mmio_peer_ctrl, 0,
                                 sndev->self_partition,
                                 sndev->self_shared_dma);
        return rc;
}

static int switchtec_ntb_add(struct device *dev)
{
        struct switchtec_dev *stdev = to_stdev(dev);
        struct switchtec_ntb *sndev;
        int rc;

        stdev->sndev = NULL;

        if (stdev->pdev->class != (PCI_CLASS_BRIDGE_OTHER << 8))
                return -ENODEV;

        sndev = kzalloc_node(sizeof(*sndev), GFP_KERNEL, dev_to_node(dev));
        if (!sndev)
                return -ENOMEM;

        sndev->stdev = stdev;
        rc = switchtec_ntb_init_sndev(sndev);
        if (rc)
                goto free_and_exit;

        switchtec_ntb_init_mw(sndev);

        rc = switchtec_ntb_init_req_id_table(sndev);
        if (rc)
                goto free_and_exit;

        rc = switchtec_ntb_init_crosslink(sndev);
        if (rc)
                goto free_and_exit;

        switchtec_ntb_init_db(sndev);
        switchtec_ntb_init_msgs(sndev);

        rc = switchtec_ntb_init_shared_mw(sndev);
        if (rc)
                goto deinit_crosslink;

        rc = switchtec_ntb_init_db_msg_irq(sndev);
        if (rc)
                goto deinit_shared_and_exit;

        /*
         * If this host crashed, the other host may think the link is
         * still up. Tell them to force it down (it will go back up
         * once we register the ntb device).
         */
        switchtec_ntb_send_msg(sndev, LINK_MESSAGE, MSG_LINK_FORCE_DOWN);

        rc = ntb_register_device(&sndev->ntb);
        if (rc)
                goto deinit_and_exit;

        stdev->sndev = sndev;
        stdev->link_notifier = switchtec_ntb_link_notification;
        dev_info(dev, "NTB device registered\n");

        return 0;

deinit_and_exit:
        switchtec_ntb_deinit_db_msg_irq(sndev);
deinit_shared_and_exit:
        switchtec_ntb_deinit_shared_mw(sndev);
deinit_crosslink:
        switchtec_ntb_deinit_crosslink(sndev);
free_and_exit:
        kfree(sndev);
        dev_err(dev, "failed to register ntb device: %d\n", rc);
        return rc;
}

static void switchtec_ntb_remove(struct device *dev)
{
        struct switchtec_dev *stdev = to_stdev(dev);
        struct switchtec_ntb *sndev = stdev->sndev;

        if (!sndev)
                return;

        stdev->link_notifier = NULL;
        stdev->sndev = NULL;
        ntb_unregister_device(&sndev->ntb);
        switchtec_ntb_deinit_db_msg_irq(sndev);
        switchtec_ntb_deinit_shared_mw(sndev);
        switchtec_ntb_deinit_crosslink(sndev);
        cancel_work_sync(&sndev->check_link_status_work);
        kfree(sndev);
        dev_info(dev, "ntb device unregistered\n");
}

static struct class_interface switchtec_interface  = {
        .add_dev = switchtec_ntb_add,
        .remove_dev = switchtec_ntb_remove,
};

static int __init switchtec_ntb_init(void)
{
        switchtec_interface.class = &switchtec_class;
        return class_interface_register(&switchtec_interface);
}
module_init(switchtec_ntb_init);

static void __exit switchtec_ntb_exit(void)
{
        class_interface_unregister(&switchtec_interface);
}
module_exit(switchtec_ntb_exit);