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374 lines
9.7 KiB
374 lines
9.7 KiB
#ifndef _HFI1_IOWAIT_H
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#define _HFI1_IOWAIT_H
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/*
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* Copyright(c) 2015, 2016 Intel Corporation.
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*
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* This file is provided under a dual BSD/GPLv2 license. When using or
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* redistributing this file, you may do so under either license.
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*
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* GPL LICENSE SUMMARY
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* BSD LICENSE
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* - Neither the name of Intel Corporation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include <linux/list.h>
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#include <linux/workqueue.h>
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#include <linux/sched.h>
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#include "sdma_txreq.h"
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/*
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* typedef (*restart_t)() - restart callback
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* @work: pointer to work structure
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*/
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typedef void (*restart_t)(struct work_struct *work);
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struct sdma_txreq;
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struct sdma_engine;
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/**
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* struct iowait - linkage for delayed progress/waiting
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* @list: used to add/insert into QP/PQ wait lists
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* @lock: uses to record the list head lock
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* @tx_head: overflow list of sdma_txreq's
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* @sleep: no space callback
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* @wakeup: space callback wakeup
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* @sdma_drained: sdma count drained
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* @iowork: workqueue overhead
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* @wait_dma: wait for sdma_busy == 0
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* @wait_pio: wait for pio_busy == 0
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* @sdma_busy: # of packets in flight
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* @count: total number of descriptors in tx_head'ed list
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* @tx_limit: limit for overflow queuing
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* @tx_count: number of tx entry's in tx_head'ed list
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*
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* This is to be embedded in user's state structure
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* (QP or PQ).
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*
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* The sleep and wakeup members are a
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* bit misnamed. They do not strictly
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* speaking sleep or wake up, but they
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* are callbacks for the ULP to implement
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* what ever queuing/dequeuing of
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* the embedded iowait and its containing struct
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* when a resource shortage like SDMA ring space is seen.
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*
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* Both potentially have locks help
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* so sleeping is not allowed.
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*
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* The wait_dma member along with the iow
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*
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* The lock field is used by waiters to record
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* the seqlock_t that guards the list head.
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* Waiters explicity know that, but the destroy
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* code that unwaits QPs does not.
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*/
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struct iowait {
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struct list_head list;
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struct list_head tx_head;
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int (*sleep)(
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struct sdma_engine *sde,
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struct iowait *wait,
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struct sdma_txreq *tx,
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uint seq,
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bool pkts_sent
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);
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void (*wakeup)(struct iowait *wait, int reason);
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void (*sdma_drained)(struct iowait *wait);
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seqlock_t *lock;
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struct work_struct iowork;
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wait_queue_head_t wait_dma;
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wait_queue_head_t wait_pio;
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atomic_t sdma_busy;
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atomic_t pio_busy;
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u32 count;
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u32 tx_limit;
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u32 tx_count;
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u8 starved_cnt;
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};
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#define SDMA_AVAIL_REASON 0
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/**
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* iowait_init() - initialize wait structure
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* @wait: wait struct to initialize
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* @tx_limit: limit for overflow queuing
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* @func: restart function for workqueue
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* @sleep: sleep function for no space
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* @resume: wakeup function for no space
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*
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* This function initializes the iowait
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* structure embedded in the QP or PQ.
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*
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*/
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static inline void iowait_init(
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struct iowait *wait,
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u32 tx_limit,
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void (*func)(struct work_struct *work),
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int (*sleep)(
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struct sdma_engine *sde,
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struct iowait *wait,
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struct sdma_txreq *tx,
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uint seq,
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bool pkts_sent),
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void (*wakeup)(struct iowait *wait, int reason),
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void (*sdma_drained)(struct iowait *wait))
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{
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wait->count = 0;
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wait->lock = NULL;
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INIT_LIST_HEAD(&wait->list);
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INIT_LIST_HEAD(&wait->tx_head);
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INIT_WORK(&wait->iowork, func);
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init_waitqueue_head(&wait->wait_dma);
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init_waitqueue_head(&wait->wait_pio);
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atomic_set(&wait->sdma_busy, 0);
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atomic_set(&wait->pio_busy, 0);
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wait->tx_limit = tx_limit;
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wait->sleep = sleep;
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wait->wakeup = wakeup;
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wait->sdma_drained = sdma_drained;
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}
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/**
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* iowait_schedule() - initialize wait structure
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* @wait: wait struct to schedule
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* @wq: workqueue for schedule
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* @cpu: cpu
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*/
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static inline void iowait_schedule(
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struct iowait *wait,
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struct workqueue_struct *wq,
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int cpu)
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{
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queue_work_on(cpu, wq, &wait->iowork);
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}
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/**
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* iowait_sdma_drain() - wait for DMAs to drain
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*
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* @wait: iowait structure
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*
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* This will delay until the iowait sdmas have
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* completed.
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*/
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static inline void iowait_sdma_drain(struct iowait *wait)
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{
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wait_event(wait->wait_dma, !atomic_read(&wait->sdma_busy));
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}
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/**
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* iowait_sdma_pending() - return sdma pending count
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*
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* @wait: iowait structure
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*
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*/
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static inline int iowait_sdma_pending(struct iowait *wait)
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{
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return atomic_read(&wait->sdma_busy);
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}
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/**
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* iowait_sdma_inc - note sdma io pending
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* @wait: iowait structure
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*/
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static inline void iowait_sdma_inc(struct iowait *wait)
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{
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atomic_inc(&wait->sdma_busy);
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}
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/**
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* iowait_sdma_add - add count to pending
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* @wait: iowait structure
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*/
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static inline void iowait_sdma_add(struct iowait *wait, int count)
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{
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atomic_add(count, &wait->sdma_busy);
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}
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/**
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* iowait_sdma_dec - note sdma complete
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* @wait: iowait structure
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*/
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static inline int iowait_sdma_dec(struct iowait *wait)
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{
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return atomic_dec_and_test(&wait->sdma_busy);
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}
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/**
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* iowait_pio_drain() - wait for pios to drain
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*
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* @wait: iowait structure
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*
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* This will delay until the iowait pios have
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* completed.
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*/
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static inline void iowait_pio_drain(struct iowait *wait)
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{
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wait_event_timeout(wait->wait_pio,
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!atomic_read(&wait->pio_busy),
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HZ);
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}
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/**
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* iowait_pio_pending() - return pio pending count
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*
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* @wait: iowait structure
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*
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*/
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static inline int iowait_pio_pending(struct iowait *wait)
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{
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return atomic_read(&wait->pio_busy);
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}
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/**
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* iowait_pio_inc - note pio pending
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* @wait: iowait structure
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*/
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static inline void iowait_pio_inc(struct iowait *wait)
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{
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atomic_inc(&wait->pio_busy);
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}
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/**
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* iowait_sdma_dec - note pio complete
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* @wait: iowait structure
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*/
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static inline int iowait_pio_dec(struct iowait *wait)
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{
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return atomic_dec_and_test(&wait->pio_busy);
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}
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/**
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* iowait_drain_wakeup() - trigger iowait_drain() waiter
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*
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* @wait: iowait structure
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*
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* This will trigger any waiters.
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*/
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static inline void iowait_drain_wakeup(struct iowait *wait)
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{
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wake_up(&wait->wait_dma);
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wake_up(&wait->wait_pio);
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if (wait->sdma_drained)
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wait->sdma_drained(wait);
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}
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/**
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* iowait_get_txhead() - get packet off of iowait list
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*
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* @wait wait struture
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*/
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static inline struct sdma_txreq *iowait_get_txhead(struct iowait *wait)
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{
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struct sdma_txreq *tx = NULL;
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if (!list_empty(&wait->tx_head)) {
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tx = list_first_entry(
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&wait->tx_head,
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struct sdma_txreq,
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list);
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list_del_init(&tx->list);
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}
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return tx;
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}
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/**
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* iowait_queue - Put the iowait on a wait queue
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* @pkts_sent: have some packets been sent before queuing?
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* @w: the iowait struct
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* @wait_head: the wait queue
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*
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* This function is called to insert an iowait struct into a
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* wait queue after a resource (eg, sdma decriptor or pio
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* buffer) is run out.
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*/
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static inline void iowait_queue(bool pkts_sent, struct iowait *w,
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struct list_head *wait_head)
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{
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/*
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* To play fair, insert the iowait at the tail of the wait queue if it
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* has already sent some packets; Otherwise, put it at the head.
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*/
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if (pkts_sent) {
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list_add_tail(&w->list, wait_head);
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w->starved_cnt = 0;
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} else {
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list_add(&w->list, wait_head);
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w->starved_cnt++;
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}
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}
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/**
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* iowait_starve_clear - clear the wait queue's starve count
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* @pkts_sent: have some packets been sent?
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* @w: the iowait struct
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*
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* This function is called to clear the starve count. If no
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* packets have been sent, the starve count will not be cleared.
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*/
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static inline void iowait_starve_clear(bool pkts_sent, struct iowait *w)
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{
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if (pkts_sent)
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w->starved_cnt = 0;
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}
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/**
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* iowait_starve_find_max - Find the maximum of the starve count
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* @w: the iowait struct
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* @max: a variable containing the max starve count
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* @idx: the index of the current iowait in an array
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* @max_idx: a variable containing the array index for the
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* iowait entry that has the max starve count
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*
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* This function is called to compare the starve count of a
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* given iowait with the given max starve count. The max starve
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* count and the index will be updated if the iowait's start
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* count is larger.
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*/
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static inline void iowait_starve_find_max(struct iowait *w, u8 *max,
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uint idx, uint *max_idx)
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{
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if (w->starved_cnt > *max) {
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*max = w->starved_cnt;
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*max_idx = idx;
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}
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}
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#endif
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