LXR linux/drivers/gpu/drm/nouveau/nvkm/subdev/timer/base.c

   1/*
   2 * Copyright 2012 Red Hat Inc.
   3 *
   4 * Permission is hereby granted, free of charge, to any person obtaining a
   5 * copy of this software and associated documentation files (the "Software"),
   6 * to deal in the Software without restriction, including without limitation
   7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8 * and/or sell copies of the Software, and to permit persons to whom the
   9 * Software is furnished to do so, subject to the following conditions:
  10 *
  11 * The above copyright notice and this permission notice shall be included in
  12 * all copies or substantial portions of the Software.
  13 *
  14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  20 * OTHER DEALINGS IN THE SOFTWARE.
  21 *
  22 * Authors: Ben Skeggs
  23 */
  24#include "priv.h"
  25
  26u64
  27nvkm_timer_read(struct nvkm_timer *tmr)
  28{
  29        return tmr->func->read(tmr);
  30}
  31
  32void
  33nvkm_timer_alarm_trigger(struct nvkm_timer *tmr)
  34{
  35        struct nvkm_alarm *alarm, *atemp;
  36        unsigned long flags;
  37        LIST_HEAD(exec);
  38
  39        /* Process pending alarms. */
  40        spin_lock_irqsave(&tmr->lock, flags);
  41        list_for_each_entry_safe(alarm, atemp, &tmr->alarms, head) {
  42                /* Have we hit the earliest alarm that hasn't gone off? */
  43                if (alarm->timestamp > nvkm_timer_read(tmr)) {
  44                        /* Schedule it.  If we didn't race, we're done. */
  45                        tmr->func->alarm_init(tmr, alarm->timestamp);
  46                        if (alarm->timestamp > nvkm_timer_read(tmr))
  47                                break;
  48                }
  49
  50                /* Move to completed list.  We'll drop the lock before
  51                 * executing the callback so it can reschedule itself.
  52                 */
  53                list_del_init(&alarm->head);
  54                list_add(&alarm->exec, &exec);
  55        }
  56
  57        /* Shut down interrupt if no more pending alarms. */
  58        if (list_empty(&tmr->alarms))
  59                tmr->func->alarm_fini(tmr);
  60        spin_unlock_irqrestore(&tmr->lock, flags);
  61
  62        /* Execute completed callbacks. */
  63        list_for_each_entry_safe(alarm, atemp, &exec, exec) {
  64                list_del(&alarm->exec);
  65                alarm->func(alarm);
  66        }
  67}
  68
  69void
  70nvkm_timer_alarm(struct nvkm_timer *tmr, u32 nsec, struct nvkm_alarm *alarm)
  71{
  72        struct nvkm_alarm *list;
  73        unsigned long flags;
  74
  75        /* Remove alarm from pending list.
  76         *
  77         * This both protects against the corruption of the list,
  78         * and implements alarm rescheduling/cancellation.
  79         */
  80        spin_lock_irqsave(&tmr->lock, flags);
  81        list_del_init(&alarm->head);
  82
  83        if (nsec) {
  84                /* Insert into pending list, ordered earliest to latest. */
  85                alarm->timestamp = nvkm_timer_read(tmr) + nsec;
  86                list_for_each_entry(list, &tmr->alarms, head) {
  87                        if (list->timestamp > alarm->timestamp)
  88                                break;
  89                }
  90
  91                list_add_tail(&alarm->head, &list->head);
  92
  93                /* Update HW if this is now the earliest alarm. */
  94                list = list_first_entry(&tmr->alarms, typeof(*list), head);
  95                if (list == alarm) {
  96                        tmr->func->alarm_init(tmr, alarm->timestamp);
  97                        /* This shouldn't happen if callers aren't stupid.
  98                         *
  99                         * Worst case scenario is that it'll take roughly
 100                         * 4 seconds for the next alarm to trigger.
 101                         */
 102                        WARN_ON(alarm->timestamp <= nvkm_timer_read(tmr));
 103                }
 104        }
 105        spin_unlock_irqrestore(&tmr->lock, flags);
 106}
 107
 108static void
 109nvkm_timer_intr(struct nvkm_subdev *subdev)
 110{
 111        struct nvkm_timer *tmr = nvkm_timer(subdev);
 112        tmr->func->intr(tmr);
 113}
 114
 115static int
 116nvkm_timer_fini(struct nvkm_subdev *subdev, bool suspend)
 117{
 118        struct nvkm_timer *tmr = nvkm_timer(subdev);
 119        tmr->func->alarm_fini(tmr);
 120        return 0;
 121}
 122
 123static int
 124nvkm_timer_init(struct nvkm_subdev *subdev)
 125{
 126        struct nvkm_timer *tmr = nvkm_timer(subdev);
 127        if (tmr->func->init)
 128                tmr->func->init(tmr);
 129        tmr->func->time(tmr, ktime_to_ns(ktime_get()));
 130        nvkm_timer_alarm_trigger(tmr);
 131        return 0;
 132}
 133
 134static void *
 135nvkm_timer_dtor(struct nvkm_subdev *subdev)
 136{
 137        return nvkm_timer(subdev);
 138}
 139
 140static const struct nvkm_subdev_func
 141nvkm_timer = {
 142        .dtor = nvkm_timer_dtor,
 143        .init = nvkm_timer_init,
 144        .fini = nvkm_timer_fini,
 145        .intr = nvkm_timer_intr,
 146};
 147
 148int
 149nvkm_timer_new_(const struct nvkm_timer_func *func, struct nvkm_device *device,
 150                int index, struct nvkm_timer **ptmr)
 151{
 152        struct nvkm_timer *tmr;
 153
 154        if (!(tmr = *ptmr = kzalloc(sizeof(*tmr), GFP_KERNEL)))
 155                return -ENOMEM;
 156
 157        nvkm_subdev_ctor(&nvkm_timer, device, index, &tmr->subdev);
 158        tmr->func = func;
 159        INIT_LIST_HEAD(&tmr->alarms);
 160        spin_lock_init(&tmr->lock);
 161        return 0;
 162}
 163