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 static void 109 nvkm_timer_intr(struct nvkm_subdev *subdev) 110 { 111 struct nvkm_timer *tmr = nvkm_timer(subdev); 112 tmr->func->intr(tmr); 113 } 114 115 static int 116 nvkm_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 } 122 123 static int 124 nvkm_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 } 133 134 static void * 135 nvkm_timer_dtor(struct nvkm_subdev *subdev) 136 { 137 return nvkm_timer(subdev); 138 } 139 140 static const struct nvkm_subdev_func 141 nvkm_timer = { 142 .dtor = nvkm_timer_dtor, 143 .init = nvkm_timer_init, 144 .fini = nvkm_timer_fini, 145 .intr = nvkm_timer_intr, 146 }; 147 148 int 149 nvkm_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