#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
* @lock: uses to record the list head lock
* @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
*
* The lock field is used by waiters to record
* the seqlock_t that guards the list head.
* Waiters explicity know that, but the destroy
* code that unwaits QPs does not.
*/
struct iowait {
struct list_head list;
struct list_head tx_head;
int (*sleep)(
struct sdma_engine *sde,
struct iowait *wait,
struct sdma_txreq *tx,
uint seq,
bool pkts_sent
);
void (*wakeup)(struct iowait *wait, int reason);
void (*sdma_drained)(struct iowait *wait);
seqlock_t *lock;
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;
u8 starved_cnt;
};
#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,
uint seq,
bool pkts_sent),
void (*wakeup)(struct iowait *wait, int reason),
void (*sdma_drained)(struct iowait *wait))
{
wait->count = 0;
wait->lock = NULL;
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;
}
/**
* iowait_queue - Put the iowait on a wait queue
* @pkts_sent: have some packets been sent before queuing?
* @w: the iowait struct
* @wait_head: the wait queue
*
* This function is called to insert an iowait struct into a
* wait queue after a resource (eg, sdma decriptor or pio
* buffer) is run out.
*/
static inline void iowait_queue(bool pkts_sent, struct iowait *w,
struct list_head *wait_head)
{
/*
* To play fair, insert the iowait at the tail of the wait queue if it
* has already sent some packets; Otherwise, put it at the head.
*/
if (pkts_sent) {
list_add_tail(&w->list, wait_head);
w->starved_cnt = 0;
} else {
list_add(&w->list, wait_head);
w->starved_cnt++;
}
}
/**
* iowait_starve_clear - clear the wait queue's starve count
* @pkts_sent: have some packets been sent?
* @w: the iowait struct
*
* This function is called to clear the starve count. If no
* packets have been sent, the starve count will not be cleared.
*/
static inline void iowait_starve_clear(bool pkts_sent, struct iowait *w)
{
if (pkts_sent)
w->starved_cnt = 0;
}
/**
* iowait_starve_find_max - Find the maximum of the starve count
* @w: the iowait struct
* @max: a variable containing the max starve count
* @idx: the index of the current iowait in an array
* @max_idx: a variable containing the array index for the
* iowait entry that has the max starve count
*
* This function is called to compare the starve count of a
* given iowait with the given max starve count. The max starve
* count and the index will be updated if the iowait's start
* count is larger.
*/
static inline void iowait_starve_find_max(struct iowait *w, u8 *max,
uint idx, uint *max_idx)
{
if (w->starved_cnt > *max) {
*max = w->starved_cnt;
*max_idx = idx;
}
}
/**
* iowait_packet_queued() - determine if a packet is already built
* @wait: the wait structure
*/
static inline bool iowait_packet_queued(struct iowait *wait)
{
return !list_empty(&wait->tx_head);
}
#endif
