/* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */
/*
 * Copyright(c) 2015 - 2018 Intel Corporation.
 */

#ifndef _HFI1_SDMA_H
#define _HFI1_SDMA_H

#include <linux/types.h>
#include <linux/list.h>
#include <asm/byteorder.h>
#include <linux/workqueue.h>
#include <linux/rculist.h>

#include "hfi.h"
#include "verbs.h"
#include "sdma_txreq.h"

/* Hardware limit */
#define MAX_DESC 64
/* Hardware limit for SDMA packet size */
#define MAX_SDMA_PKT_SIZE ((16 * 1024) - 1)

#define SDMA_MAP_NONE          0
#define SDMA_MAP_SINGLE        1
#define SDMA_MAP_PAGE          2

#define SDMA_AHG_VALUE_MASK          0xffff
#define SDMA_AHG_VALUE_SHIFT         0
#define SDMA_AHG_INDEX_MASK          0xf
#define SDMA_AHG_INDEX_SHIFT         16
#define SDMA_AHG_FIELD_LEN_MASK      0xf
#define SDMA_AHG_FIELD_LEN_SHIFT     20
#define SDMA_AHG_FIELD_START_MASK    0x1f
#define SDMA_AHG_FIELD_START_SHIFT   24
#define SDMA_AHG_UPDATE_ENABLE_MASK  0x1
#define SDMA_AHG_UPDATE_ENABLE_SHIFT 31

/* AHG modes */

/*
 * Be aware the ordering and values
 * for SDMA_AHG_APPLY_UPDATE[123]
 * are assumed in generating a skip
 * count in submit_tx() in sdma.c
 */
#define SDMA_AHG_NO_AHG              0
#define SDMA_AHG_COPY                1
#define SDMA_AHG_APPLY_UPDATE1       2
#define SDMA_AHG_APPLY_UPDATE2       3
#define SDMA_AHG_APPLY_UPDATE3       4

/*
 * Bits defined in the send DMA descriptor.
 */
#define SDMA_DESC0_FIRST_DESC_FLAG      BIT_ULL(63)
#define SDMA_DESC0_LAST_DESC_FLAG       BIT_ULL(62)
#define SDMA_DESC0_BYTE_COUNT_SHIFT     48
#define SDMA_DESC0_BYTE_COUNT_WIDTH     14
#define SDMA_DESC0_BYTE_COUNT_MASK \
        ((1ULL << SDMA_DESC0_BYTE_COUNT_WIDTH) - 1)
#define SDMA_DESC0_BYTE_COUNT_SMASK \
        (SDMA_DESC0_BYTE_COUNT_MASK << SDMA_DESC0_BYTE_COUNT_SHIFT)
#define SDMA_DESC0_PHY_ADDR_SHIFT       0
#define SDMA_DESC0_PHY_ADDR_WIDTH       48
#define SDMA_DESC0_PHY_ADDR_MASK \
        ((1ULL << SDMA_DESC0_PHY_ADDR_WIDTH) - 1)
#define SDMA_DESC0_PHY_ADDR_SMASK \
        (SDMA_DESC0_PHY_ADDR_MASK << SDMA_DESC0_PHY_ADDR_SHIFT)

#define SDMA_DESC1_HEADER_UPDATE1_SHIFT 32
#define SDMA_DESC1_HEADER_UPDATE1_WIDTH 32
#define SDMA_DESC1_HEADER_UPDATE1_MASK \
        ((1ULL << SDMA_DESC1_HEADER_UPDATE1_WIDTH) - 1)
#define SDMA_DESC1_HEADER_UPDATE1_SMASK \
        (SDMA_DESC1_HEADER_UPDATE1_MASK << SDMA_DESC1_HEADER_UPDATE1_SHIFT)
#define SDMA_DESC1_HEADER_MODE_SHIFT    13
#define SDMA_DESC1_HEADER_MODE_WIDTH    3
#define SDMA_DESC1_HEADER_MODE_MASK \
        ((1ULL << SDMA_DESC1_HEADER_MODE_WIDTH) - 1)
#define SDMA_DESC1_HEADER_MODE_SMASK \
        (SDMA_DESC1_HEADER_MODE_MASK << SDMA_DESC1_HEADER_MODE_SHIFT)
#define SDMA_DESC1_HEADER_INDEX_SHIFT   8
#define SDMA_DESC1_HEADER_INDEX_WIDTH   5
#define SDMA_DESC1_HEADER_INDEX_MASK \
        ((1ULL << SDMA_DESC1_HEADER_INDEX_WIDTH) - 1)
#define SDMA_DESC1_HEADER_INDEX_SMASK \
        (SDMA_DESC1_HEADER_INDEX_MASK << SDMA_DESC1_HEADER_INDEX_SHIFT)
#define SDMA_DESC1_HEADER_DWS_SHIFT     4
#define SDMA_DESC1_HEADER_DWS_WIDTH     4
#define SDMA_DESC1_HEADER_DWS_MASK \
        ((1ULL << SDMA_DESC1_HEADER_DWS_WIDTH) - 1)
#define SDMA_DESC1_HEADER_DWS_SMASK \
        (SDMA_DESC1_HEADER_DWS_MASK << SDMA_DESC1_HEADER_DWS_SHIFT)
#define SDMA_DESC1_GENERATION_SHIFT     2
#define SDMA_DESC1_GENERATION_WIDTH     2
#define SDMA_DESC1_GENERATION_MASK \
        ((1ULL << SDMA_DESC1_GENERATION_WIDTH) - 1)
#define SDMA_DESC1_GENERATION_SMASK \
        (SDMA_DESC1_GENERATION_MASK << SDMA_DESC1_GENERATION_SHIFT)
#define SDMA_DESC1_INT_REQ_FLAG         BIT_ULL(1)
#define SDMA_DESC1_HEAD_TO_HOST_FLAG    BIT_ULL(0)

enum sdma_states {
        sdma_state_s00_hw_down,
        sdma_state_s10_hw_start_up_halt_wait,
        sdma_state_s15_hw_start_up_clean_wait,
        sdma_state_s20_idle,
        sdma_state_s30_sw_clean_up_wait,
        sdma_state_s40_hw_clean_up_wait,
        sdma_state_s50_hw_halt_wait,
        sdma_state_s60_idle_halt_wait,
        sdma_state_s80_hw_freeze,
        sdma_state_s82_freeze_sw_clean,
        sdma_state_s99_running,
};

enum sdma_events {
        sdma_event_e00_go_hw_down,
        sdma_event_e10_go_hw_start,
        sdma_event_e15_hw_halt_done,
        sdma_event_e25_hw_clean_up_done,
        sdma_event_e30_go_running,
        sdma_event_e40_sw_cleaned,
        sdma_event_e50_hw_cleaned,
        sdma_event_e60_hw_halted,
        sdma_event_e70_go_idle,
        sdma_event_e80_hw_freeze,
        sdma_event_e81_hw_frozen,
        sdma_event_e82_hw_unfreeze,
        sdma_event_e85_link_down,
        sdma_event_e90_sw_halted,
};

struct sdma_set_state_action {
        unsigned op_enable:1;
        unsigned op_intenable:1;
        unsigned op_halt:1;
        unsigned op_cleanup:1;
        unsigned go_s99_running_tofalse:1;
        unsigned go_s99_running_totrue:1;
};

struct sdma_state {
        struct kref          kref;
        struct completion    comp;
        enum sdma_states current_state;
        unsigned             current_op;
        unsigned             go_s99_running;
        /* debugging/development */
        enum sdma_states previous_state;
        unsigned             previous_op;
        enum sdma_events last_event;
};

/**
 * DOC: sdma exported routines
 *
 * These sdma routines fit into three categories:
 * - The SDMA API for building and submitting packets
 *   to the ring
 *
 * - Initialization and tear down routines to buildup
 *   and tear down SDMA
 *
 * - ISR entrances to handle interrupts, state changes
 *   and errors
 */

/**
 * DOC: sdma PSM/verbs API
 *
 * The sdma API is designed to be used by both PSM
 * and verbs to supply packets to the SDMA ring.
 *
 * The usage of the API is as follows:
 *
 * Embed a struct iowait in the QP or
 * PQ.  The iowait should be initialized with a
 * call to iowait_init().
 *
 * The user of the API should create an allocation method
 * for their version of the txreq. slabs, pre-allocated lists,
 * and dma pools can be used.  Once the user's overload of
 * the sdma_txreq has been allocated, the sdma_txreq member
 * must be initialized with sdma_txinit() or sdma_txinit_ahg().
 *
 * The txreq must be declared with the sdma_txreq first.
 *
 * The tx request, once initialized,  is manipulated with calls to
 * sdma_txadd_daddr(), sdma_txadd_page(), or sdma_txadd_kvaddr()
 * for each disjoint memory location.  It is the user's responsibility
 * to understand the packet boundaries and page boundaries to do the
 * appropriate number of sdma_txadd_* calls..  The user
 * must be prepared to deal with failures from these routines due to
 * either memory allocation or dma_mapping failures.
 *
 * The mapping specifics for each memory location are recorded
 * in the tx. Memory locations added with sdma_txadd_page()
 * and sdma_txadd_kvaddr() are automatically mapped when added
 * to the tx and nmapped as part of the progress processing in the
 * SDMA interrupt handling.
 *
 * sdma_txadd_daddr() is used to add an dma_addr_t memory to the
 * tx.   An example of a use case would be a pre-allocated
 * set of headers allocated via dma_pool_alloc() or
 * dma_alloc_coherent().  For these memory locations, it
 * is the responsibility of the user to handle that unmapping.
 * (This would usually be at an unload or job termination.)
 *
 * The routine sdma_send_txreq() is used to submit
 * a tx to the ring after the appropriate number of
 * sdma_txadd_* have been done.
 *
 * If it is desired to send a burst of sdma_txreqs, sdma_send_txlist()
 * can be used to submit a list of packets.
 *
 * The user is free to use the link overhead in the struct sdma_txreq as
 * long as the tx isn't in flight.
 *
 * The extreme degenerate case of the number of descriptors
 * exceeding the ring size is automatically handled as
 * memory locations are added.  An overflow of the descriptor
 * array that is part of the sdma_txreq is also automatically
 * handled.
 *
 */

/**
 * DOC: Infrastructure calls
 *
 * sdma_init() is used to initialize data structures and
 * CSRs for the desired number of SDMA engines.
 *
 * sdma_start() is used to kick the SDMA engines initialized
 * with sdma_init().   Interrupts must be enabled at this
 * point since aspects of the state machine are interrupt
 * driven.
 *
 * sdma_engine_error() and sdma_engine_interrupt() are
 * entrances for interrupts.
 *
 * sdma_map_init() is for the management of the mapping
 * table when the number of vls is changed.
 *
 */

/*
 * struct hw_sdma_desc - raw 128 bit SDMA descriptor
 *
 * This is the raw descriptor in the SDMA ring
 */
struct hw_sdma_desc {
        /* private:  don't use directly */
        __le64 qw[2];
};

/**
 * struct sdma_engine - Data pertaining to each SDMA engine.
 * @dd: a back-pointer to the device data
 * @ppd: per port back-pointer
 * @imask: mask for irq manipulation
 * @idle_mask: mask for determining if an interrupt is due to sdma_idle
 *
 * This structure has the state for each sdma_engine.
 *
 * Accessing to non public fields are not supported
 * since the private members are subject to change.
 */
struct sdma_engine {
        /* read mostly */
        struct hfi1_devdata *dd;
        struct hfi1_pportdata *ppd;
        /* private: */
        void __iomem *tail_csr;
        u64 imask;                      /* clear interrupt mask */
        u64 idle_mask;
        u64 progress_mask;
        u64 int_mask;
        /* private: */
        volatile __le64      *head_dma; /* DMA'ed by chip */
        /* private: */
        dma_addr_t            head_phys;
        /* private: */
        struct hw_sdma_desc *descq;
        /* private: */
        unsigned descq_full_count;
        struct sdma_txreq **tx_ring;
        /* private: */
        dma_addr_t            descq_phys;
        /* private */
        u32 sdma_mask;
        /* private */
        struct sdma_state state;
        /* private */
        int cpu;
        /* private: */
        u8 sdma_shift;
        /* private: */
        u8 this_idx; /* zero relative engine */
        /* protect changes to senddmactrl shadow */
        spinlock_t senddmactrl_lock;
        /* private: */
        u64 p_senddmactrl;              /* shadow per-engine SendDmaCtrl */

        /* read/write using tail_lock */
        spinlock_t            tail_lock ____cacheline_aligned_in_smp;
#ifdef CONFIG_HFI1_DEBUG_SDMA_ORDER
        /* private: */
        u64                   tail_sn;
#endif
        /* private: */
        u32                   descq_tail;
        /* private: */
        unsigned long         ahg_bits;
        /* private: */
        u16                   desc_avail;
        /* private: */
        u16                   tx_tail;
        /* private: */
        u16 descq_cnt;

        /* read/write using head_lock */
        /* private: */
        seqlock_t            head_lock ____cacheline_aligned_in_smp;
#ifdef CONFIG_HFI1_DEBUG_SDMA_ORDER
        /* private: */
        u64                   head_sn;
#endif
        /* private: */
        u32                   descq_head;
        /* private: */
        u16                   tx_head;
        /* private: */
        u64                   last_status;
        /* private */
        u64                     err_cnt;
        /* private */
        u64                     sdma_int_cnt;
        u64                     idle_int_cnt;
        u64                     progress_int_cnt;

        /* private: */
        seqlock_t            waitlock;
        struct list_head      dmawait;

        /* CONFIG SDMA for now, just blindly duplicate */
        /* private: */
        struct tasklet_struct sdma_hw_clean_up_task
                ____cacheline_aligned_in_smp;

        /* private: */
        struct tasklet_struct sdma_sw_clean_up_task
                ____cacheline_aligned_in_smp;
        /* private: */
        struct work_struct err_halt_worker;
        /* private */
        struct timer_list     err_progress_check_timer;
        u32                   progress_check_head;
        /* private: */
        struct work_struct flush_worker;
        /* protect flush list */
        spinlock_t flushlist_lock;
        /* private: */
        struct list_head flushlist;
        struct cpumask cpu_mask;
        struct kobject kobj;
        u32 msix_intr;
};

int sdma_init(struct hfi1_devdata *dd, u8 port);
void sdma_start(struct hfi1_devdata *dd);
void sdma_exit(struct hfi1_devdata *dd);
void sdma_clean(struct hfi1_devdata *dd, size_t num_engines);
void sdma_all_running(struct hfi1_devdata *dd);
void sdma_freeze_notify(struct hfi1_devdata *dd, int go_idle);
void sdma_freeze(struct hfi1_devdata *dd);
void sdma_unfreeze(struct hfi1_devdata *dd);
void sdma_wait(struct hfi1_devdata *dd);

/**
 * sdma_empty() - idle engine test
 * @engine: sdma engine
 *
 * Currently used by verbs as a latency optimization.
 *
 * Return:
 * 1 - empty, 0 - non-empty
 */
static inline int sdma_empty(struct sdma_engine *sde)
{
        return sde->descq_tail == sde->descq_head;
}

static inline u16 sdma_descq_freecnt(struct sdma_engine *sde)
{
        return sde->descq_cnt -
                (sde->descq_tail -
                 READ_ONCE(sde->descq_head)) - 1;
}

static inline u16 sdma_descq_inprocess(struct sdma_engine *sde)
{
        return sde->descq_cnt - sdma_descq_freecnt(sde);
}

/*
 * Either head_lock or tail lock required to see
 * a steady state.
 */
static inline int __sdma_running(struct sdma_engine *engine)
{
        return engine->state.current_state == sdma_state_s99_running;
}

/**
 * sdma_running() - state suitability test
 * @engine: sdma engine
 *
 * sdma_running probes the internal state to determine if it is suitable
 * for submitting packets.
 *
 * Return:
 * 1 - ok to submit, 0 - not ok to submit
 *
 */
static inline int sdma_running(struct sdma_engine *engine)
{
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&engine->tail_lock, flags);
        ret = __sdma_running(engine);
        spin_unlock_irqrestore(&engine->tail_lock, flags);
        return ret;
}

void _sdma_txreq_ahgadd(
        struct sdma_txreq *tx,
        u8 num_ahg,
        u8 ahg_entry,
        u32 *ahg,
        u8 ahg_hlen);

/**
 * sdma_txinit_ahg() - initialize an sdma_txreq struct with AHG
 * @tx: tx request to initialize
 * @flags: flags to key last descriptor additions
 * @tlen: total packet length (pbc + headers + data)
 * @ahg_entry: ahg entry to use  (0 - 31)
 * @num_ahg: ahg descriptor for first descriptor (0 - 9)
 * @ahg: array of AHG descriptors (up to 9 entries)
 * @ahg_hlen: number of bytes from ASIC entry to use
 * @cb: callback
 *
 * The allocation of the sdma_txreq and it enclosing structure is user
 * dependent.  This routine must be called to initialize the user independent
 * fields.
 *
 * The currently supported flags are SDMA_TXREQ_F_URGENT,
 * SDMA_TXREQ_F_AHG_COPY, and SDMA_TXREQ_F_USE_AHG.
 *
 * SDMA_TXREQ_F_URGENT is used for latency sensitive situations where the
 * completion is desired as soon as possible.
 *
 * SDMA_TXREQ_F_AHG_COPY causes the header in the first descriptor to be
 * copied to chip entry. SDMA_TXREQ_F_USE_AHG causes the code to add in
 * the AHG descriptors into the first 1 to 3 descriptors.
 *
 * Completions of submitted requests can be gotten on selected
 * txreqs by giving a completion routine callback to sdma_txinit() or
 * sdma_txinit_ahg().  The environment in which the callback runs
 * can be from an ISR, a tasklet, or a thread, so no sleeping
 * kernel routines can be used.   Aspects of the sdma ring may
 * be locked so care should be taken with locking.
 *
 * The callback pointer can be NULL to avoid any callback for the packet
 * being submitted. The callback will be provided this tx, a status, and a flag.
 *
 * The status will be one of SDMA_TXREQ_S_OK, SDMA_TXREQ_S_SENDERROR,
 * SDMA_TXREQ_S_ABORTED, or SDMA_TXREQ_S_SHUTDOWN.
 *
 * The flag, if the is the iowait had been used, indicates the iowait
 * sdma_busy count has reached zero.
 *
 * user data portion of tlen should be precise.   The sdma_txadd_* entrances
 * will pad with a descriptor references 1 - 3 bytes when the number of bytes
 * specified in tlen have been supplied to the sdma_txreq.
 *
 * ahg_hlen is used to determine the number of on-chip entry bytes to
 * use as the header.   This is for cases where the stored header is
 * larger than the header to be used in a packet.  This is typical
 * for verbs where an RDMA_WRITE_FIRST is larger than the packet in
 * and RDMA_WRITE_MIDDLE.
 *
 */
static inline int sdma_txinit_ahg(
        struct sdma_txreq *tx,
        u16 flags,
        u16 tlen,
        u8 ahg_entry,
        u8 num_ahg,
        u32 *ahg,
        u8 ahg_hlen,
        void (*cb)(struct sdma_txreq *, int))
{
        if (tlen == 0)
                return -ENODATA;
        if (tlen > MAX_SDMA_PKT_SIZE)
                return -EMSGSIZE;
        tx->desc_limit = ARRAY_SIZE(tx->descs);
        tx->descp = &tx->descs[0];
        INIT_LIST_HEAD(&tx->list);
        tx->num_desc = 0;
        tx->flags = flags;
        tx->complete = cb;
        tx->coalesce_buf = NULL;
        tx->wait = NULL;
        tx->packet_len = tlen;
        tx->tlen = tx->packet_len;
        tx->descs[0].qw[0] = SDMA_DESC0_FIRST_DESC_FLAG;
        tx->descs[0].qw[1] = 0;
        if (flags & SDMA_TXREQ_F_AHG_COPY)
                tx->descs[0].qw[1] |=
                        (((u64)ahg_entry & SDMA_DESC1_HEADER_INDEX_MASK)
                                << SDMA_DESC1_HEADER_INDEX_SHIFT) |
                        (((u64)SDMA_AHG_COPY & SDMA_DESC1_HEADER_MODE_MASK)
                                << SDMA_DESC1_HEADER_MODE_SHIFT);
        else if (flags & SDMA_TXREQ_F_USE_AHG && num_ahg)
                _sdma_txreq_ahgadd(tx, num_ahg, ahg_entry, ahg, ahg_hlen);
        return 0;
}

/**
 * sdma_txinit() - initialize an sdma_txreq struct (no AHG)
 * @tx: tx request to initialize
 * @flags: flags to key last descriptor additions
 * @tlen: total packet length (pbc + headers + data)
 * @cb: callback pointer
 *
 * The allocation of the sdma_txreq and it enclosing structure is user
 * dependent.  This routine must be called to initialize the user
 * independent fields.
 *
 * The currently supported flags is SDMA_TXREQ_F_URGENT.
 *
 * SDMA_TXREQ_F_URGENT is used for latency sensitive situations where the
 * completion is desired as soon as possible.
 *
 * Completions of submitted requests can be gotten on selected
 * txreqs by giving a completion routine callback to sdma_txinit() or
 * sdma_txinit_ahg().  The environment in which the callback runs
 * can be from an ISR, a tasklet, or a thread, so no sleeping
 * kernel routines can be used.   The head size of the sdma ring may
 * be locked so care should be taken with locking.
 *
 * The callback pointer can be NULL to avoid any callback for the packet
 * being submitted.
 *
 * The callback, if non-NULL,  will be provided this tx and a status.  The
 * status will be one of SDMA_TXREQ_S_OK, SDMA_TXREQ_S_SENDERROR,
 * SDMA_TXREQ_S_ABORTED, or SDMA_TXREQ_S_SHUTDOWN.
 *
 */
static inline int sdma_txinit(
        struct sdma_txreq *tx,
        u16 flags,
        u16 tlen,
        void (*cb)(struct sdma_txreq *, int))
{
        return sdma_txinit_ahg(tx, flags, tlen, 0, 0, NULL, 0, cb);
}

/* helpers - don't use */
static inline int sdma_mapping_type(struct sdma_desc *d)
{
        return (d->qw[1] & SDMA_DESC1_GENERATION_SMASK)
                >> SDMA_DESC1_GENERATION_SHIFT;
}

static inline size_t sdma_mapping_len(struct sdma_desc *d)
{
        return (d->qw[0] & SDMA_DESC0_BYTE_COUNT_SMASK)
                >> SDMA_DESC0_BYTE_COUNT_SHIFT;
}

static inline dma_addr_t sdma_mapping_addr(struct sdma_desc *d)
{
        return (d->qw[0] & SDMA_DESC0_PHY_ADDR_SMASK)
                >> SDMA_DESC0_PHY_ADDR_SHIFT;
}

static inline void make_tx_sdma_desc(
        struct sdma_txreq *tx,
        int type,
        dma_addr_t addr,
        size_t len,
        void *pinning_ctx,
        void (*ctx_get)(void *),
        void (*ctx_put)(void *))
{
        struct sdma_desc *desc = &tx->descp[tx->num_desc];

        if (!tx->num_desc) {
                /* qw[0] zero; qw[1] first, ahg mode already in from init */
                desc->qw[1] |= ((u64)type & SDMA_DESC1_GENERATION_MASK)
                                << SDMA_DESC1_GENERATION_SHIFT;
        } else {
                desc->qw[0] = 0;
                desc->qw[1] = ((u64)type & SDMA_DESC1_GENERATION_MASK)
                                << SDMA_DESC1_GENERATION_SHIFT;
        }
        desc->qw[0] |= (((u64)addr & SDMA_DESC0_PHY_ADDR_MASK)
                                << SDMA_DESC0_PHY_ADDR_SHIFT) |
                        (((u64)len & SDMA_DESC0_BYTE_COUNT_MASK)
                                << SDMA_DESC0_BYTE_COUNT_SHIFT);

        desc->pinning_ctx = pinning_ctx;
        desc->ctx_put = ctx_put;
        if (pinning_ctx && ctx_get)
                ctx_get(pinning_ctx);
}

/* helper to extend txreq */
int ext_coal_sdma_tx_descs(struct hfi1_devdata *dd, struct sdma_txreq *tx,
                           int type, void *kvaddr, struct page *page,
                           unsigned long offset, u16 len);
int _pad_sdma_tx_descs(struct hfi1_devdata *, struct sdma_txreq *);
void __sdma_txclean(struct hfi1_devdata *, struct sdma_txreq *);

static inline void sdma_txclean(struct hfi1_devdata *dd, struct sdma_txreq *tx)
{
        if (tx->num_desc)
                __sdma_txclean(dd, tx);
}

/* helpers used by public routines */
static inline void _sdma_close_tx(struct hfi1_devdata *dd,
                                  struct sdma_txreq *tx)
{
        u16 last_desc = tx->num_desc - 1;

        tx->descp[last_desc].qw[0] |= SDMA_DESC0_LAST_DESC_FLAG;
        tx->descp[last_desc].qw[1] |= dd->default_desc1;
        if (tx->flags & SDMA_TXREQ_F_URGENT)
                tx->descp[last_desc].qw[1] |= (SDMA_DESC1_HEAD_TO_HOST_FLAG |
                                               SDMA_DESC1_INT_REQ_FLAG);
}

static inline int _sdma_txadd_daddr(
        struct hfi1_devdata *dd,
        int type,
        struct sdma_txreq *tx,
        dma_addr_t addr,
        u16 len,
        void *pinning_ctx,
        void (*ctx_get)(void *),
        void (*ctx_put)(void *))
{
        int rval = 0;

        make_tx_sdma_desc(
                tx,
                type,
                addr, len,
                pinning_ctx, ctx_get, ctx_put);
        WARN_ON(len > tx->tlen);
        tx->num_desc++;
        tx->tlen -= len;
        /* special cases for last */
        if (!tx->tlen) {
                if (tx->packet_len & (sizeof(u32) - 1)) {
                        rval = _pad_sdma_tx_descs(dd, tx);
                        if (rval)
                                return rval;
                } else {
                        _sdma_close_tx(dd, tx);
                }
        }
        return rval;
}

/**
 * sdma_txadd_page() - add a page to the sdma_txreq
 * @dd: the device to use for mapping
 * @tx: tx request to which the page is added
 * @page: page to map
 * @offset: offset within the page
 * @len: length in bytes
 * @pinning_ctx: context to be stored on struct sdma_desc .pinning_ctx. Not
 *               added if coalesce buffer is used. E.g. pointer to pinned-page
 *               cache entry for the sdma_desc.
 * @ctx_get: optional function to take reference to @pinning_ctx. Not called if
 *           @pinning_ctx is NULL.
 * @ctx_put: optional function to release reference to @pinning_ctx after
 *           sdma_desc completes. May be called in interrupt context so must
 *           not sleep. Not called if @pinning_ctx is NULL.
 *
 * This is used to add a page/offset/length descriptor.
 *
 * The mapping/unmapping of the page/offset/len is automatically handled.
 *
 * Return:
 * 0 - success, -ENOSPC - mapping fail, -ENOMEM - couldn't
 * extend/coalesce descriptor array
 */
static inline int sdma_txadd_page(
        struct hfi1_devdata *dd,
        struct sdma_txreq *tx,
        struct page *page,
        unsigned long offset,
        u16 len,
        void *pinning_ctx,
        void (*ctx_get)(void *),
        void (*ctx_put)(void *))
{
        dma_addr_t addr;
        int rval;

        if ((unlikely(tx->num_desc == tx->desc_limit))) {
                rval = ext_coal_sdma_tx_descs(dd, tx, SDMA_MAP_PAGE,
                                              NULL, page, offset, len);
                if (rval <= 0)
                        return rval;
        }

        addr = dma_map_page(
                       &dd->pcidev->dev,
                       page,
                       offset,
                       len,
                       DMA_TO_DEVICE);

        if (unlikely(dma_mapping_error(&dd->pcidev->dev, addr))) {
                __sdma_txclean(dd, tx);
                return -ENOSPC;
        }

        return _sdma_txadd_daddr(dd, SDMA_MAP_PAGE, tx, addr, len,
                                 pinning_ctx, ctx_get, ctx_put);
}

/**
 * sdma_txadd_daddr() - add a dma address to the sdma_txreq
 * @dd: the device to use for mapping
 * @tx: sdma_txreq to which the page is added
 * @addr: dma address mapped by caller
 * @len: length in bytes
 *
 * This is used to add a descriptor for memory that is already dma mapped.
 *
 * In this case, there is no unmapping as part of the progress processing for
 * this memory location.
 *
 * Return:
 * 0 - success, -ENOMEM - couldn't extend descriptor array
 */

static inline int sdma_txadd_daddr(
        struct hfi1_devdata *dd,
        struct sdma_txreq *tx,
        dma_addr_t addr,
        u16 len)
{
        int rval;

        if ((unlikely(tx->num_desc == tx->desc_limit))) {
                rval = ext_coal_sdma_tx_descs(dd, tx, SDMA_MAP_NONE,
                                              NULL, NULL, 0, 0);
                if (rval <= 0)
                        return rval;
        }

        return _sdma_txadd_daddr(dd, SDMA_MAP_NONE, tx, addr, len,
                                 NULL, NULL, NULL);
}

/**
 * sdma_txadd_kvaddr() - add a kernel virtual address to sdma_txreq
 * @dd: the device to use for mapping
 * @tx: sdma_txreq to which the page is added
 * @kvaddr: the kernel virtual address
 * @len: length in bytes
 *
 * This is used to add a descriptor referenced by the indicated kvaddr and
 * len.
 *
 * The mapping/unmapping of the kvaddr and len is automatically handled.
 *
 * Return:
 * 0 - success, -ENOSPC - mapping fail, -ENOMEM - couldn't extend/coalesce
 * descriptor array
 */
static inline int sdma_txadd_kvaddr(
        struct hfi1_devdata *dd,
        struct sdma_txreq *tx,
        void *kvaddr,
        u16 len)
{
        dma_addr_t addr;
        int rval;

        if ((unlikely(tx->num_desc == tx->desc_limit))) {
                rval = ext_coal_sdma_tx_descs(dd, tx, SDMA_MAP_SINGLE,
                                              kvaddr, NULL, 0, len);
                if (rval <= 0)
                        return rval;
        }

        addr = dma_map_single(
                       &dd->pcidev->dev,
                       kvaddr,
                       len,
                       DMA_TO_DEVICE);

        if (unlikely(dma_mapping_error(&dd->pcidev->dev, addr))) {
                __sdma_txclean(dd, tx);
                return -ENOSPC;
        }

        return _sdma_txadd_daddr(dd, SDMA_MAP_SINGLE, tx, addr, len,
                                 NULL, NULL, NULL);
}

struct iowait_work;

int sdma_send_txreq(struct sdma_engine *sde,
                    struct iowait_work *wait,
                    struct sdma_txreq *tx,
                    bool pkts_sent);
int sdma_send_txlist(struct sdma_engine *sde,
                     struct iowait_work *wait,
                     struct list_head *tx_list,
                     u16 *count_out);

int sdma_ahg_alloc(struct sdma_engine *sde);
void sdma_ahg_free(struct sdma_engine *sde, int ahg_index);

/**
 * sdma_build_ahg - build ahg descriptor
 * @data
 * @dwindex
 * @startbit
 * @bits
 *
 * Build and return a 32 bit descriptor.
 */
static inline u32 sdma_build_ahg_descriptor(
        u16 data,
        u8 dwindex,
        u8 startbit,
        u8 bits)
{
        return (u32)(1UL << SDMA_AHG_UPDATE_ENABLE_SHIFT |
                ((startbit & SDMA_AHG_FIELD_START_MASK) <<
                SDMA_AHG_FIELD_START_SHIFT) |
                ((bits & SDMA_AHG_FIELD_LEN_MASK) <<
                SDMA_AHG_FIELD_LEN_SHIFT) |
                ((dwindex & SDMA_AHG_INDEX_MASK) <<
                SDMA_AHG_INDEX_SHIFT) |
                ((data & SDMA_AHG_VALUE_MASK) <<
                SDMA_AHG_VALUE_SHIFT));
}

/**
 * sdma_progress - use seq number of detect head progress
 * @sde: sdma_engine to check
 * @seq: base seq count
 * @tx: txreq for which we need to check descriptor availability
 *
 * This is used in the appropriate spot in the sleep routine
 * to check for potential ring progress.  This routine gets the
 * seqcount before queuing the iowait structure for progress.
 *
 * If the seqcount indicates that progress needs to be checked,
 * re-submission is detected by checking whether the descriptor
 * queue has enough descriptor for the txreq.
 */
static inline unsigned sdma_progress(struct sdma_engine *sde, unsigned seq,
                                     struct sdma_txreq *tx)
{
        if (read_seqretry(&sde->head_lock, seq)) {
                sde->desc_avail = sdma_descq_freecnt(sde);
                if (tx->num_desc > sde->desc_avail)
                        return 0;
                return 1;
        }
        return 0;
}

/* for use by interrupt handling */
void sdma_engine_error(struct sdma_engine *sde, u64 status);
void sdma_engine_interrupt(struct sdma_engine *sde, u64 status);

/*
 *
 * The diagram below details the relationship of the mapping structures
 *
 * Since the mapping now allows for non-uniform engines per vl, the
 * number of engines for a vl is either the vl_engines[vl] or
 * a computation based on num_sdma/num_vls:
 *
 * For example:
 * nactual = vl_engines ? vl_engines[vl] : num_sdma/num_vls
 *
 * n = roundup to next highest power of 2 using nactual
 *
 * In the case where there are num_sdma/num_vls doesn't divide
 * evenly, the extras are added from the last vl downward.
 *
 * For the case where n > nactual, the engines are assigned
 * in a round robin fashion wrapping back to the first engine
 * for a particular vl.
 *
 *               dd->sdma_map
 *                    |                                   sdma_map_elem[0]
 *                    |                                +--------------------+
 *                    v                                |       mask         |
 *               sdma_vl_map                           |--------------------|
 *      +--------------------------+                   | sde[0] -> eng 1    |
 *      |    list (RCU)            |                   |--------------------|
 *      |--------------------------|                 ->| sde[1] -> eng 2    |
 *      |    mask                  |              --/  |--------------------|
 *      |--------------------------|            -/     |        *           |
 *      |    actual_vls (max 8)    |          -/       |--------------------|
 *      |--------------------------|       --/         | sde[n-1] -> eng n  |
 *      |    vls (max 8)           |     -/            +--------------------+
 *      |--------------------------|  --/
 *      |    map[0]                |-/
 *      |--------------------------|                   +---------------------+
 *      |    map[1]                |---                |       mask          |
 *      |--------------------------|   \----           |---------------------|
 *      |           *              |        \--        | sde[0] -> eng 1+n   |
 *      |           *              |           \----   |---------------------|
 *      |           *              |                \->| sde[1] -> eng 2+n   |
 *      |--------------------------|                   |---------------------|
 *      |   map[vls - 1]           |-                  |         *           |
 *      +--------------------------+ \-                |---------------------|
 *                                     \-              | sde[m-1] -> eng m+n |
 *                                       \             +---------------------+
 *                                        \-
 *                                          \
 *                                           \-        +----------------------+
 *                                             \-      |       mask           |
 *                                               \     |----------------------|
 *                                                \-   | sde[0] -> eng 1+m+n  |
 *                                                  \- |----------------------|
 *                                                    >| sde[1] -> eng 2+m+n  |
 *                                                     |----------------------|
 *                                                     |         *            |
 *                                                     |----------------------|
 *                                                     | sde[o-1] -> eng o+m+n|
 *                                                     +----------------------+
 *
 */

/**
 * struct sdma_map_elem - mapping for a vl
 * @mask - selector mask
 * @sde - array of engines for this vl
 *
 * The mask is used to "mod" the selector
 * to produce index into the trailing
 * array of sdes.
 */
struct sdma_map_elem {
        u32 mask;
        struct sdma_engine *sde[];
};

/**
 * struct sdma_map_el - mapping for a vl
 * @engine_to_vl - map of an engine to a vl
 * @list - rcu head for free callback
 * @mask - vl mask to "mod" the vl to produce an index to map array
 * @actual_vls - number of vls
 * @vls - number of vls rounded to next power of 2
 * @map - array of sdma_map_elem entries
 *
 * This is the parent mapping structure.  The trailing
 * members of the struct point to sdma_map_elem entries, which
 * in turn point to an array of sde's for that vl.
 */
struct sdma_vl_map {
        s8 engine_to_vl[TXE_NUM_SDMA_ENGINES];
        struct rcu_head list;
        u32 mask;
        u8 actual_vls;
        u8 vls;
        struct sdma_map_elem *map[];
};

int sdma_map_init(
        struct hfi1_devdata *dd,
        u8 port,
        u8 num_vls,
        u8 *vl_engines);

/* slow path */
void _sdma_engine_progress_schedule(struct sdma_engine *sde);

/**
 * sdma_engine_progress_schedule() - schedule progress on engine
 * @sde: sdma_engine to schedule progress
 *
 * This is the fast path.
 *
 */
static inline void sdma_engine_progress_schedule(
        struct sdma_engine *sde)
{
        if (!sde || sdma_descq_inprocess(sde) < (sde->descq_cnt / 8))
                return;
        _sdma_engine_progress_schedule(sde);
}

struct sdma_engine *sdma_select_engine_sc(
        struct hfi1_devdata *dd,
        u32 selector,
        u8 sc5);

struct sdma_engine *sdma_select_engine_vl(
        struct hfi1_devdata *dd,
        u32 selector,
        u8 vl);

struct sdma_engine *sdma_select_user_engine(struct hfi1_devdata *dd,
                                            u32 selector, u8 vl);
ssize_t sdma_get_cpu_to_sde_map(struct sdma_engine *sde, char *buf);
ssize_t sdma_set_cpu_to_sde_map(struct sdma_engine *sde, const char *buf,
                                size_t count);
int sdma_engine_get_vl(struct sdma_engine *sde);
void sdma_seqfile_dump_sde(struct seq_file *s, struct sdma_engine *);
void sdma_seqfile_dump_cpu_list(struct seq_file *s, struct hfi1_devdata *dd,
                                unsigned long cpuid);

#ifdef CONFIG_SDMA_VERBOSITY
void sdma_dumpstate(struct sdma_engine *);
#endif
static inline char *slashstrip(char *s)
{
        char *r = s;

        while (*s)
                if (*s++ == '/')
                        r = s;
        return r;
}

u16 sdma_get_descq_cnt(void);

extern uint mod_num_sdma;

void sdma_update_lmc(struct hfi1_devdata *dd, u64 mask, u32 lid);
#endif