/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Shared Memory Communications over RDMA (SMC-R) and RoCE
 *
 * Work Requests exploiting Infiniband API
 *
 * Copyright IBM Corp. 2016
 *
 * Author(s):  Steffen Maier <maier@linux.vnet.ibm.com>
 */

#ifndef SMC_WR_H
#define SMC_WR_H

#include <linux/atomic.h>
#include <rdma/ib_verbs.h>
#include <asm/div64.h>

#include "smc.h"
#include "smc_core.h"

#define SMC_WR_TX_WAIT_FREE_SLOT_TIME   (10 * HZ)

#define SMC_WR_TX_SIZE 44 /* actual size of wr_send data (<=SMC_WR_BUF_SIZE) */

#define SMC_WR_TX_PEND_PRIV_SIZE 32

struct smc_wr_tx_pend_priv {
        u8                      priv[SMC_WR_TX_PEND_PRIV_SIZE];
};

typedef void (*smc_wr_tx_handler)(struct smc_wr_tx_pend_priv *,
                                  struct smc_link *,
                                  enum ib_wc_status);

typedef bool (*smc_wr_tx_filter)(struct smc_wr_tx_pend_priv *,
                                 unsigned long);

typedef void (*smc_wr_tx_dismisser)(struct smc_wr_tx_pend_priv *);

struct smc_wr_rx_handler {
        struct hlist_node       list;   /* hash table collision resolution */
        void                    (*handler)(struct ib_wc *, void *);
        u8                      type;
};

/* Only used by RDMA write WRs.
 * All other WRs (CDC/LLC) use smc_wr_tx_send handling WR_ID implicitly
 */
static inline long smc_wr_tx_get_next_wr_id(struct smc_link *link)
{
        return atomic_long_inc_return(&link->wr_tx_id);
}

static inline void smc_wr_tx_set_wr_id(atomic_long_t *wr_tx_id, long val)
{
        atomic_long_set(wr_tx_id, val);
}

static inline bool smc_wr_tx_link_hold(struct smc_link *link)
{
        if (!smc_link_sendable(link))
                return false;
        percpu_ref_get(&link->wr_tx_refs);
        return true;
}

static inline void smc_wr_tx_link_put(struct smc_link *link)
{
        percpu_ref_put(&link->wr_tx_refs);
}

static inline void smc_wr_drain_cq(struct smc_link *lnk)
{
        wait_event(lnk->wr_rx_empty_wait, lnk->wr_rx_id_compl == lnk->wr_rx_id);
}

static inline void smc_wr_wakeup_tx_wait(struct smc_link *lnk)
{
        wake_up_all(&lnk->wr_tx_wait);
}

static inline void smc_wr_wakeup_reg_wait(struct smc_link *lnk)
{
        wake_up(&lnk->wr_reg_wait);
}

/* post a new receive work request to fill a completed old work request entry */
static inline int smc_wr_rx_post(struct smc_link *link)
{
        int rc;
        u64 wr_id, temp_wr_id;
        u32 index;

        wr_id = ++link->wr_rx_id; /* tasklet context, thus not atomic */
        temp_wr_id = wr_id;
        index = do_div(temp_wr_id, link->wr_rx_cnt);
        link->wr_rx_ibs[index].wr_id = wr_id;
        rc = ib_post_recv(link->roce_qp, &link->wr_rx_ibs[index], NULL);
        return rc;
}

int smc_wr_create_link(struct smc_link *lnk);
int smc_wr_alloc_link_mem(struct smc_link *lnk);
int smc_wr_alloc_lgr_mem(struct smc_link_group *lgr);
void smc_wr_free_link(struct smc_link *lnk);
void smc_wr_free_link_mem(struct smc_link *lnk);
void smc_wr_free_lgr_mem(struct smc_link_group *lgr);
void smc_wr_remember_qp_attr(struct smc_link *lnk);
void smc_wr_remove_dev(struct smc_ib_device *smcibdev);
void smc_wr_add_dev(struct smc_ib_device *smcibdev);

int smc_wr_tx_get_free_slot(struct smc_link *link, smc_wr_tx_handler handler,
                            struct smc_wr_buf **wr_buf,
                            struct smc_rdma_wr **wrs,
                            struct smc_wr_tx_pend_priv **wr_pend_priv);
int smc_wr_tx_get_v2_slot(struct smc_link *link,
                          smc_wr_tx_handler handler,
                          struct smc_wr_v2_buf **wr_buf,
                          struct smc_wr_tx_pend_priv **wr_pend_priv);
int smc_wr_tx_put_slot(struct smc_link *link,
                       struct smc_wr_tx_pend_priv *wr_pend_priv);
int smc_wr_tx_send(struct smc_link *link,
                   struct smc_wr_tx_pend_priv *wr_pend_priv);
int smc_wr_tx_v2_send(struct smc_link *link,
                      struct smc_wr_tx_pend_priv *priv, int len);
int smc_wr_tx_send_wait(struct smc_link *link, struct smc_wr_tx_pend_priv *priv,
                        unsigned long timeout);
void smc_wr_tx_cq_handler(struct ib_cq *ib_cq, void *cq_context);
void smc_wr_tx_wait_no_pending_sends(struct smc_link *link);

int smc_wr_rx_register_handler(struct smc_wr_rx_handler *handler);
int smc_wr_rx_post_init(struct smc_link *link);
void smc_wr_rx_cq_handler(struct ib_cq *ib_cq, void *cq_context);
int smc_wr_reg_send(struct smc_link *link, struct ib_mr *mr);

#endif /* SMC_WR_H */