/* 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_BUF_CNT 16	/* # of ctrl buffers per link */
  
  #define SMC_WR_TX_WAIT_FREE_SLOT_TIME	(10 * HZ)
  #define SMC_WR_TX_WAIT_PENDING_TIME	(5 * 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);
  }
  
  /* 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)
  {
  	struct ib_recv_wr *bad_recv_wr = NULL;
  	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], &bad_recv_wr);
  	return rc;
  }
  
  int smc_wr_create_link(struct smc_link *lnk);
  int smc_wr_alloc_link_mem(struct smc_link *lnk);
  void smc_wr_free_link(struct smc_link *lnk);
  void smc_wr_free_link_mem(struct smc_link *lnk);
  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_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);
  void smc_wr_tx_cq_handler(struct ib_cq *ib_cq, void *cq_context);

  bool smc_wr_tx_has_pending(struct smc_link *link, u8 wr_rx_hdr_type,
  			   smc_wr_tx_filter filter, unsigned long data);

  void smc_wr_tx_dismiss_slots(struct smc_link *lnk, u8 wr_rx_hdr_type,
  			     smc_wr_tx_filter filter,
  			     smc_wr_tx_dismisser dismisser,
  			     unsigned long data);

  
  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 */