drivers/staging/rdma/hfi1/iowait.h

   1 #ifndef _HFI1_IOWAIT_H
   2 #define _HFI1_IOWAIT_H
   3 /*
   4  * Copyright(c) 2015, 2016 Intel Corporation.
   5  *
   6  * This file is provided under a dual BSD/GPLv2 license.  When using or
   7  * redistributing this file, you may do so under either license.
   8  *
   9  * GPL LICENSE SUMMARY
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of version 2 of the GNU General Public License as
  13  * published by the Free Software Foundation.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * BSD LICENSE
  21  *
  22  * Redistribution and use in source and binary forms, with or without
  23  * modification, are permitted provided that the following conditions
  24  * are met:
  25  *
  26  *  - Redistributions of source code must retain the above copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  *  - Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in
  30  *    the documentation and/or other materials provided with the
  31  *    distribution.
  32  *  - Neither the name of Intel Corporation nor the names of its
  33  *    contributors may be used to endorse or promote products derived
  34  *    from this software without specific prior written permission.
  35  *
  36  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  37  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  38  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  39  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  40  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  41  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  42  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  43  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  44  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  45  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  46  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  47  *
  48  */
  49
  50 #include <linux/list.h>
  51 #include <linux/workqueue.h>
  52 #include <linux/sched.h>
  53
  54 #include "sdma_txreq.h"
  55
  56 /*
  57  * typedef (*restart_t)() - restart callback
  58  * @work: pointer to work structure
  59  */
  60 typedef void (*restart_t)(struct work_struct *work);
  61
  62 struct sdma_txreq;
  63 struct sdma_engine;
  64 /**
  65  * struct iowait - linkage for delayed progress/waiting
  66  * @list: used to add/insert into QP/PQ wait lists
  67  * @tx_head: overflow list of sdma_txreq's
  68  * @sleep: no space callback
  69  * @wakeup: space callback wakeup
  70  * @sdma_drained: sdma count drained
  71  * @iowork: workqueue overhead
  72  * @wait_dma: wait for sdma_busy == 0
  73  * @wait_pio: wait for pio_busy == 0
  74  * @sdma_busy: # of packets in flight
  75  * @count: total number of descriptors in tx_head'ed list
  76  * @tx_limit: limit for overflow queuing
  77  * @tx_count: number of tx entry's in tx_head'ed list
  78  *
  79  * This is to be embedded in user's state structure
  80  * (QP or PQ).
  81  *
  82  * The sleep and wakeup members are a
  83  * bit misnamed.   They do not strictly
  84  * speaking sleep or wake up, but they
  85  * are callbacks for the ULP to implement
  86  * what ever queuing/dequeuing of
  87  * the embedded iowait and its containing struct
  88  * when a resource shortage like SDMA ring space is seen.
  89  *
  90  * Both potentially have locks help
  91  * so sleeping is not allowed.
  92  *
  93  * The wait_dma member along with the iow
  94  */
  95
  96 struct iowait {
  97         struct list_head list;
  98         struct list_head tx_head;
  99         int (*sleep)(
 100                 struct sdma_engine *sde,
 101                 struct iowait *wait,
 102                 struct sdma_txreq *tx,
 103                 unsigned seq);
 104         void (*wakeup)(struct iowait *wait, int reason);
 105         void (*sdma_drained)(struct iowait *wait);
 106         struct work_struct iowork;
 107         wait_queue_head_t wait_dma;
 108         wait_queue_head_t wait_pio;
 109         atomic_t sdma_busy;
 110         atomic_t pio_busy;
 111         u32 count;
 112         u32 tx_limit;
 113         u32 tx_count;
 114 };
 115
 116 #define SDMA_AVAIL_REASON 0
 117
 118 /**
 119  * iowait_init() - initialize wait structure
 120  * @wait: wait struct to initialize
 121  * @tx_limit: limit for overflow queuing
 122  * @func: restart function for workqueue
 123  * @sleep: sleep function for no space
 124  * @resume: wakeup function for no space
 125  *
 126  * This function initializes the iowait
 127  * structure embedded in the QP or PQ.
 128  *
 129  */
 130
 131 static inline void iowait_init(
 132         struct iowait *wait,
 133         u32 tx_limit,
 134         void (*func)(struct work_struct *work),
 135         int (*sleep)(
 136                 struct sdma_engine *sde,
 137                 struct iowait *wait,
 138                 struct sdma_txreq *tx,
 139                 unsigned seq),
 140         void (*wakeup)(struct iowait *wait, int reason),
 141         void (*sdma_drained)(struct iowait *wait))
 142 {
 143         wait->count = 0;
 144         INIT_LIST_HEAD(&wait->list);
 145         INIT_LIST_HEAD(&wait->tx_head);
 146         INIT_WORK(&wait->iowork, func);
 147         init_waitqueue_head(&wait->wait_dma);
 148         init_waitqueue_head(&wait->wait_pio);
 149         atomic_set(&wait->sdma_busy, 0);
 150         atomic_set(&wait->pio_busy, 0);
 151         wait->tx_limit = tx_limit;
 152         wait->sleep = sleep;
 153         wait->wakeup = wakeup;
 154         wait->sdma_drained = sdma_drained;
 155 }
 156
 157 /**
 158  * iowait_schedule() - initialize wait structure
 159  * @wait: wait struct to schedule
 160  * @wq: workqueue for schedule
 161  * @cpu: cpu
 162  */
 163 static inline void iowait_schedule(
 164         struct iowait *wait,
 165         struct workqueue_struct *wq,
 166         int cpu)
 167 {
 168         queue_work_on(cpu, wq, &wait->iowork);
 169 }
 170
 171 /**
 172  * iowait_sdma_drain() - wait for DMAs to drain
 173  *
 174  * @wait: iowait structure
 175  *
 176  * This will delay until the iowait sdmas have
 177  * completed.
 178  */
 179 static inline void iowait_sdma_drain(struct iowait *wait)
 180 {
 181         wait_event(wait->wait_dma, !atomic_read(&wait->sdma_busy));
 182 }
 183
 184 /**
 185  * iowait_sdma_pending() - return sdma pending count
 186  *
 187  * @wait: iowait structure
 188  *
 189  */
 190 static inline int iowait_sdma_pending(struct iowait *wait)
 191 {
 192         return atomic_read(&wait->sdma_busy);
 193 }
 194
 195 /**
 196  * iowait_sdma_inc - note sdma io pending
 197  * @wait: iowait structure
 198  */
 199 static inline void iowait_sdma_inc(struct iowait *wait)
 200 {
 201         atomic_inc(&wait->sdma_busy);
 202 }
 203
 204 /**
 205  * iowait_sdma_add - add count to pending
 206  * @wait: iowait structure
 207  */
 208 static inline void iowait_sdma_add(struct iowait *wait, int count)
 209 {
 210         atomic_add(count, &wait->sdma_busy);
 211 }
 212
 213 /**
 214  * iowait_sdma_dec - note sdma complete
 215  * @wait: iowait structure
 216  */
 217 static inline int iowait_sdma_dec(struct iowait *wait)
 218 {
 219         return atomic_dec_and_test(&wait->sdma_busy);
 220 }
 221
 222 /**
 223  * iowait_pio_drain() - wait for pios to drain
 224  *
 225  * @wait: iowait structure
 226  *
 227  * This will delay until the iowait pios have
 228  * completed.
 229  */
 230 static inline void iowait_pio_drain(struct iowait *wait)
 231 {
 232         wait_event_timeout(wait->wait_pio,
 233                            !atomic_read(&wait->pio_busy),
 234                            HZ);
 235 }
 236
 237 /**
 238  * iowait_pio_pending() - return pio pending count
 239  *
 240  * @wait: iowait structure
 241  *
 242  */
 243 static inline int iowait_pio_pending(struct iowait *wait)
 244 {
 245         return atomic_read(&wait->pio_busy);
 246 }
 247
 248 /**
 249  * iowait_pio_inc - note pio pending
 250  * @wait: iowait structure
 251  */
 252 static inline void iowait_pio_inc(struct iowait *wait)
 253 {
 254         atomic_inc(&wait->pio_busy);
 255 }
 256
 257 /**
 258  * iowait_sdma_dec - note pio complete
 259  * @wait: iowait structure
 260  */
 261 static inline int iowait_pio_dec(struct iowait *wait)
 262 {
 263         return atomic_dec_and_test(&wait->pio_busy);
 264 }
 265
 266 /**
 267  * iowait_drain_wakeup() - trigger iowait_drain() waiter
 268  *
 269  * @wait: iowait structure
 270  *
 271  * This will trigger any waiters.
 272  */
 273 static inline void iowait_drain_wakeup(struct iowait *wait)
 274 {
 275         wake_up(&wait->wait_dma);
 276         wake_up(&wait->wait_pio);
 277         if (wait->sdma_drained)
 278                 wait->sdma_drained(wait);
 279 }
 280
 281 /**
 282  * iowait_get_txhead() - get packet off of iowait list
 283  *
 284  * @wait wait struture
 285  */
 286 static inline struct sdma_txreq *iowait_get_txhead(struct iowait *wait)
 287 {
 288         struct sdma_txreq *tx = NULL;
 289
 290         if (!list_empty(&wait->tx_head)) {
 291                 tx = list_first_entry(
 292                         &wait->tx_head,
 293                         struct sdma_txreq,
 294                         list);
 295                 list_del_init(&tx->list);
 296         }
 297         return tx;
 298 }
 299
 300 #endif