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
  26 u64
  27 nvkm_timer_read(struct nvkm_timer *tmr)
  28 {
  29         return tmr->func->read(tmr);
  30 }
  31
  32 void
  33 nvkm_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
  69 void
  70 nvkm_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
 108 void
 109 nvkm_timer_alarm_cancel(struct nvkm_timer *tmr, struct nvkm_alarm *alarm)
 110 {
 111         unsigned long flags;
 112         spin_lock_irqsave(&tmr->lock, flags);
 113         list_del_init(&alarm->head);
 114         spin_unlock_irqrestore(&tmr->lock, flags);
 115 }
 116
 117 static void
 118 nvkm_timer_intr(struct nvkm_subdev *subdev)
 119 {
 120         struct nvkm_timer *tmr = nvkm_timer(subdev);
 121         tmr->func->intr(tmr);
 122 }
 123
 124 static int
 125 nvkm_timer_fini(struct nvkm_subdev *subdev, bool suspend)
 126 {
 127         struct nvkm_timer *tmr = nvkm_timer(subdev);
 128         tmr->func->alarm_fini(tmr);
 129         return 0;
 130 }
 131
 132 static int
 133 nvkm_timer_init(struct nvkm_subdev *subdev)
 134 {
 135         struct nvkm_timer *tmr = nvkm_timer(subdev);
 136         if (tmr->func->init)
 137                 tmr->func->init(tmr);
 138         tmr->func->time(tmr, ktime_to_ns(ktime_get()));
 139         nvkm_timer_alarm_trigger(tmr);
 140         return 0;
 141 }
 142
 143 static void *
 144 nvkm_timer_dtor(struct nvkm_subdev *subdev)
 145 {
 146         return nvkm_timer(subdev);
 147 }
 148
 149 static const struct nvkm_subdev_func
 150 nvkm_timer = {
 151         .dtor = nvkm_timer_dtor,
 152         .init = nvkm_timer_init,
 153         .fini = nvkm_timer_fini,
 154         .intr = nvkm_timer_intr,
 155 };
 156
 157 int
 158 nvkm_timer_new_(const struct nvkm_timer_func *func, struct nvkm_device *device,
 159                 int index, struct nvkm_timer **ptmr)
 160 {
 161         struct nvkm_timer *tmr;
 162
 163         if (!(tmr = *ptmr = kzalloc(sizeof(*tmr), GFP_KERNEL)))
 164                 return -ENOMEM;
 165
 166         nvkm_subdev_ctor(&nvkm_timer, device, index, &tmr->subdev);
 167         tmr->func = func;
 168         INIT_LIST_HEAD(&tmr->alarms);
 169         spin_lock_init(&tmr->lock);
 170         return 0;
 171 }