#ifndef _HFI1_IOWAIT_H
  #define _HFI1_IOWAIT_H
  /*

   * Copyright(c) 2015, 2016 Intel Corporation.

   *
   * This file is provided under a dual BSD/GPLv2 license.  When using or
   * redistributing this file, you may do so under either license.
   *
   * GPL LICENSE SUMMARY
   *

   * This program is free software; you can redistribute it and/or modify
   * it under the terms of version 2 of the GNU General Public License as
   * published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
   *
   * BSD LICENSE
   *

   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   *  - Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *  - Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *  - Neither the name of Intel Corporation nor the names of its
   *    contributors may be used to endorse or promote products derived
   *    from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   */
  
  #include <linux/list.h>
  #include <linux/workqueue.h>
  #include <linux/sched.h>

  #include "sdma_txreq.h"

  /*
   * typedef (*restart_t)() - restart callback
   * @work: pointer to work structure
   */
  typedef void (*restart_t)(struct work_struct *work);
  
  struct sdma_txreq;
  struct sdma_engine;
  /**
   * struct iowait - linkage for delayed progress/waiting
   * @list: used to add/insert into QP/PQ wait lists
   * @tx_head: overflow list of sdma_txreq's
   * @sleep: no space callback

   * @wakeup: space callback wakeup
   * @sdma_drained: sdma count drained

   * @iowork: workqueue overhead
   * @wait_dma: wait for sdma_busy == 0

   * @wait_pio: wait for pio_busy == 0

   * @sdma_busy: # of packets in flight
   * @count: total number of descriptors in tx_head'ed list
   * @tx_limit: limit for overflow queuing
   * @tx_count: number of tx entry's in tx_head'ed list
   *
   * This is to be embedded in user's state structure
   * (QP or PQ).
   *
   * The sleep and wakeup members are a
   * bit misnamed.   They do not strictly
   * speaking sleep or wake up, but they
   * are callbacks for the ULP to implement
   * what ever queuing/dequeuing of
   * the embedded iowait and its containing struct
   * when a resource shortage like SDMA ring space is seen.
   *
   * Both potentially have locks help
   * so sleeping is not allowed.
   *
   * The wait_dma member along with the iow
   */
  
  struct iowait {
  	struct list_head list;
  	struct list_head tx_head;
  	int (*sleep)(
  		struct sdma_engine *sde,
  		struct iowait *wait,
  		struct sdma_txreq *tx,
  		unsigned seq);
  	void (*wakeup)(struct iowait *wait, int reason);

  	void (*sdma_drained)(struct iowait *wait);

  	struct work_struct iowork;
  	wait_queue_head_t wait_dma;

  	wait_queue_head_t wait_pio;

  	atomic_t sdma_busy;

  	atomic_t pio_busy;

  	u32 count;
  	u32 tx_limit;
  	u32 tx_count;
  };
  
  #define SDMA_AVAIL_REASON 0
  
  /**
   * iowait_init() - initialize wait structure
   * @wait: wait struct to initialize
   * @tx_limit: limit for overflow queuing
   * @func: restart function for workqueue
   * @sleep: sleep function for no space

   * @resume: wakeup function for no space

   *
   * This function initializes the iowait
   * structure embedded in the QP or PQ.
   *
   */
  
  static inline void iowait_init(
  	struct iowait *wait,
  	u32 tx_limit,
  	void (*func)(struct work_struct *work),
  	int (*sleep)(
  		struct sdma_engine *sde,
  		struct iowait *wait,
  		struct sdma_txreq *tx,
  		unsigned seq),

  	void (*wakeup)(struct iowait *wait, int reason),
  	void (*sdma_drained)(struct iowait *wait))

  {
  	wait->count = 0;
  	INIT_LIST_HEAD(&wait->list);
  	INIT_LIST_HEAD(&wait->tx_head);
  	INIT_WORK(&wait->iowork, func);
  	init_waitqueue_head(&wait->wait_dma);

  	init_waitqueue_head(&wait->wait_pio);

  	atomic_set(&wait->sdma_busy, 0);

  	atomic_set(&wait->pio_busy, 0);

  	wait->tx_limit = tx_limit;
  	wait->sleep = sleep;
  	wait->wakeup = wakeup;

  	wait->sdma_drained = sdma_drained;

  }
  
  /**
   * iowait_schedule() - initialize wait structure
   * @wait: wait struct to schedule
   * @wq: workqueue for schedule

   * @cpu: cpu

   */
  static inline void iowait_schedule(
  	struct iowait *wait,

  	struct workqueue_struct *wq,
  	int cpu)

  {

  	queue_work_on(cpu, wq, &wait->iowork);

  }
  
  /**
   * iowait_sdma_drain() - wait for DMAs to drain
   *
   * @wait: iowait structure
   *
   * This will delay until the iowait sdmas have
   * completed.
   */
  static inline void iowait_sdma_drain(struct iowait *wait)
  {
  	wait_event(wait->wait_dma, !atomic_read(&wait->sdma_busy));
  }
  
  /**

   * iowait_sdma_pending() - return sdma pending count
   *
   * @wait: iowait structure
   *
   */
  static inline int iowait_sdma_pending(struct iowait *wait)
  {
  	return atomic_read(&wait->sdma_busy);
  }
  
  /**
   * iowait_sdma_inc - note sdma io pending
   * @wait: iowait structure
   */
  static inline void iowait_sdma_inc(struct iowait *wait)
  {
  	atomic_inc(&wait->sdma_busy);
  }
  
  /**
   * iowait_sdma_add - add count to pending
   * @wait: iowait structure
   */
  static inline void iowait_sdma_add(struct iowait *wait, int count)
  {
  	atomic_add(count, &wait->sdma_busy);
  }
  
  /**
   * iowait_sdma_dec - note sdma complete
   * @wait: iowait structure
   */
  static inline int iowait_sdma_dec(struct iowait *wait)
  {
  	return atomic_dec_and_test(&wait->sdma_busy);
  }
  
  /**
   * iowait_pio_drain() - wait for pios to drain
   *
   * @wait: iowait structure
   *
   * This will delay until the iowait pios have
   * completed.
   */
  static inline void iowait_pio_drain(struct iowait *wait)
  {
  	wait_event_timeout(wait->wait_pio,
  			   !atomic_read(&wait->pio_busy),
  			   HZ);
  }
  
  /**
   * iowait_pio_pending() - return pio pending count
   *
   * @wait: iowait structure
   *
   */
  static inline int iowait_pio_pending(struct iowait *wait)
  {
  	return atomic_read(&wait->pio_busy);
  }
  
  /**
   * iowait_pio_inc - note pio pending
   * @wait: iowait structure
   */
  static inline void iowait_pio_inc(struct iowait *wait)
  {
  	atomic_inc(&wait->pio_busy);
  }
  
  /**
   * iowait_sdma_dec - note pio complete
   * @wait: iowait structure
   */
  static inline int iowait_pio_dec(struct iowait *wait)
  {
  	return atomic_dec_and_test(&wait->pio_busy);
  }
  
  /**

   * iowait_drain_wakeup() - trigger iowait_drain() waiter
   *
   * @wait: iowait structure
   *
   * This will trigger any waiters.
   */
  static inline void iowait_drain_wakeup(struct iowait *wait)
  {
  	wake_up(&wait->wait_dma);

  	wake_up(&wait->wait_pio);

  	if (wait->sdma_drained)
  		wait->sdma_drained(wait);

  }

  /**
   * iowait_get_txhead() - get packet off of iowait list
   *
   * @wait wait struture
   */
  static inline struct sdma_txreq *iowait_get_txhead(struct iowait *wait)
  {
  	struct sdma_txreq *tx = NULL;
  
  	if (!list_empty(&wait->tx_head)) {
  		tx = list_first_entry(
  			&wait->tx_head,
  			struct sdma_txreq,
  			list);
  		list_del_init(&tx->list);
  	}
  	return tx;
  }

  #endif