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_move_tail(&alarm->head, &exec);
  54         }
  55
  56         /* Shut down interrupt if no more pending alarms. */
  57         if (list_empty(&tmr->alarms))
  58                 tmr->func->alarm_fini(tmr);
  59         spin_unlock_irqrestore(&tmr->lock, flags);
  60
  61         /* Execute completed callbacks. */
  62         list_for_each_entry_safe(alarm, atemp, &exec, head) {
  63                 list_del_init(&alarm->head);
  64                 alarm->func(alarm);
  65         }
  66 }
  67
  68 void
  69 nvkm_timer_alarm(struct nvkm_timer *tmr, u32 nsec, struct nvkm_alarm *alarm)
  70 {
  71         struct nvkm_alarm *list;
  72         unsigned long flags;
  73
  74         /* Remove alarm from pending list.
  75          *
  76          * This both protects against the corruption of the list,
  77          * and implements alarm rescheduling/cancellation.
  78          */
  79         spin_lock_irqsave(&tmr->lock, flags);
  80         list_del_init(&alarm->head);
  81
  82         if (nsec) {
  83                 /* Insert into pending list, ordered earliest to latest. */
  84                 alarm->timestamp = nvkm_timer_read(tmr) + nsec;
  85                 list_for_each_entry(list, &tmr->alarms, head) {
  86                         if (list->timestamp > alarm->timestamp)
  87                                 break;
  88                 }
  89
  90                 list_add_tail(&alarm->head, &list->head);
  91
  92                 /* Update HW if this is now the earliest alarm. */
  93                 list = list_first_entry(&tmr->alarms, typeof(*list), head);
  94                 if (list == alarm) {
  95                         tmr->func->alarm_init(tmr, alarm->timestamp);
  96                         /* This shouldn't happen if callers aren't stupid.
  97                          *
  98                          * Worst case scenario is that it'll take roughly
  99                          * 4 seconds for the next alarm to trigger.
 100                          */
 101                         WARN_ON(alarm->timestamp <= nvkm_timer_read(tmr));
 102                 }
 103         }
 104         spin_unlock_irqrestore(&tmr->lock, flags);
 105 }
 106
 107 void
 108 nvkm_timer_alarm_cancel(struct nvkm_timer *tmr, struct nvkm_alarm *alarm)
 109 {
 110         unsigned long flags;
 111         spin_lock_irqsave(&tmr->lock, flags);
 112         list_del_init(&alarm->head);
 113         spin_unlock_irqrestore(&tmr->lock, flags);
 114 }
 115
 116 static void
 117 nvkm_timer_intr(struct nvkm_subdev *subdev)
 118 {
 119         struct nvkm_timer *tmr = nvkm_timer(subdev);
 120         tmr->func->intr(tmr);
 121 }
 122
 123 static int
 124 nvkm_timer_fini(struct nvkm_subdev *subdev, bool suspend)
 125 {
 126         struct nvkm_timer *tmr = nvkm_timer(subdev);
 127         tmr->func->alarm_fini(tmr);
 128         return 0;
 129 }
 130
 131 static int
 132 nvkm_timer_init(struct nvkm_subdev *subdev)
 133 {
 134         struct nvkm_timer *tmr = nvkm_timer(subdev);
 135         if (tmr->func->init)
 136                 tmr->func->init(tmr);
 137         tmr->func->time(tmr, ktime_to_ns(ktime_get()));
 138         nvkm_timer_alarm_trigger(tmr);
 139         return 0;
 140 }
 141
 142 static void *
 143 nvkm_timer_dtor(struct nvkm_subdev *subdev)
 144 {
 145         return nvkm_timer(subdev);
 146 }
 147
 148 static const struct nvkm_subdev_func
 149 nvkm_timer = {
 150         .dtor = nvkm_timer_dtor,
 151         .init = nvkm_timer_init,
 152         .fini = nvkm_timer_fini,
 153         .intr = nvkm_timer_intr,
 154 };
 155
 156 int
 157 nvkm_timer_new_(const struct nvkm_timer_func *func, struct nvkm_device *device,
 158                 int index, struct nvkm_timer **ptmr)
 159 {
 160         struct nvkm_timer *tmr;
 161
 162         if (!(tmr = *ptmr = kzalloc(sizeof(*tmr), GFP_KERNEL)))
 163                 return -ENOMEM;
 164
 165         nvkm_subdev_ctor(&nvkm_timer, device, index, &tmr->subdev);
 166         tmr->func = func;
 167         INIT_LIST_HEAD(&tmr->alarms);
 168         spin_lock_init(&tmr->lock);
 169         return 0;
 170 }