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
26s64
27nvkm_timer_wait_test(struct nvkm_timer_wait *wait)
28{
29	struct nvkm_subdev *subdev = &wait->tmr->subdev;
30	u64 time = nvkm_timer_read(wait->tmr);
31
32	if (wait->reads == 0) {
33		wait->time0 = time;
34		wait->time1 = time;
35	}
36
37	if (wait->time1 == time) {
38		if (wait->reads++ == 16) {
39			nvkm_fatal(subdev, "stalled at %016llx\n", time);
40			return -ETIMEDOUT;
41		}
42	} else {
43		wait->time1 = time;
44		wait->reads = 1;
45	}
46
47	if (wait->time1 - wait->time0 > wait->limit)
48		return -ETIMEDOUT;
49
50	return wait->time1 - wait->time0;
51}
52
53void
54nvkm_timer_wait_init(struct nvkm_device *device, u64 nsec,
55		     struct nvkm_timer_wait *wait)
56{
57	wait->tmr = device->timer;
58	wait->limit = nsec;
59	wait->reads = 0;
60}
61
62u64
63nvkm_timer_read(struct nvkm_timer *tmr)
64{
65	return tmr->func->read(tmr);
66}
67
68void
69nvkm_timer_alarm_trigger(struct nvkm_timer *tmr)
70{
71	struct nvkm_alarm *alarm, *atemp;
72	unsigned long flags;
73	LIST_HEAD(exec);
74
75	/* Process pending alarms. */
76	spin_lock_irqsave(&tmr->lock, flags);
77	list_for_each_entry_safe(alarm, atemp, &tmr->alarms, head) {
78		/* Have we hit the earliest alarm that hasn't gone off? */
79		if (alarm->timestamp > nvkm_timer_read(tmr)) {
80			/* Schedule it.  If we didn't race, we're done. */
81			tmr->func->alarm_init(tmr, alarm->timestamp);
82			if (alarm->timestamp > nvkm_timer_read(tmr))
83				break;
84		}
85
86		/* Move to completed list.  We'll drop the lock before
87		 * executing the callback so it can reschedule itself.
88		 */
89		list_del_init(&alarm->head);
90		list_add(&alarm->exec, &exec);
91	}
92
93	/* Shut down interrupt if no more pending alarms. */
94	if (list_empty(&tmr->alarms))
95		tmr->func->alarm_fini(tmr);
96	spin_unlock_irqrestore(&tmr->lock, flags);
97
98	/* Execute completed callbacks. */
99	list_for_each_entry_safe(alarm, atemp, &exec, exec) {
100		list_del(&alarm->exec);
101		alarm->func(alarm);
102	}
103}
104
105void
106nvkm_timer_alarm(struct nvkm_timer *tmr, u32 nsec, struct nvkm_alarm *alarm)
107{
108	struct nvkm_alarm *list;
109	unsigned long flags;
110
111	/* Remove alarm from pending list.
112	 *
113	 * This both protects against the corruption of the list,
114	 * and implements alarm rescheduling/cancellation.
115	 */
116	spin_lock_irqsave(&tmr->lock, flags);
117	list_del_init(&alarm->head);
118
119	if (nsec) {
120		/* Insert into pending list, ordered earliest to latest. */
121		alarm->timestamp = nvkm_timer_read(tmr) + nsec;
122		list_for_each_entry(list, &tmr->alarms, head) {
123			if (list->timestamp > alarm->timestamp)
124				break;
125		}
126
127		list_add_tail(&alarm->head, &list->head);
128
129		/* Update HW if this is now the earliest alarm. */
130		list = list_first_entry(&tmr->alarms, typeof(*list), head);
131		if (list == alarm) {
132			tmr->func->alarm_init(tmr, alarm->timestamp);
133			/* This shouldn't happen if callers aren't stupid.
134			 *
135			 * Worst case scenario is that it'll take roughly
136			 * 4 seconds for the next alarm to trigger.
137			 */
138			WARN_ON(alarm->timestamp <= nvkm_timer_read(tmr));
139		}
140	}
141	spin_unlock_irqrestore(&tmr->lock, flags);
142}
143
144static void
145nvkm_timer_intr(struct nvkm_subdev *subdev)
146{
147	struct nvkm_timer *tmr = nvkm_timer(subdev);
148	tmr->func->intr(tmr);
149}
150
151static int
152nvkm_timer_fini(struct nvkm_subdev *subdev, bool suspend)
153{
154	struct nvkm_timer *tmr = nvkm_timer(subdev);
155	tmr->func->alarm_fini(tmr);
156	return 0;
157}
158
159static int
160nvkm_timer_init(struct nvkm_subdev *subdev)
161{
162	struct nvkm_timer *tmr = nvkm_timer(subdev);
163	if (tmr->func->init)
164		tmr->func->init(tmr);
165	tmr->func->time(tmr, ktime_to_ns(ktime_get()));
166	nvkm_timer_alarm_trigger(tmr);
167	return 0;
168}
169
170static void *
171nvkm_timer_dtor(struct nvkm_subdev *subdev)
172{
173	return nvkm_timer(subdev);
174}
175
176static const struct nvkm_subdev_func
177nvkm_timer = {
178	.dtor = nvkm_timer_dtor,
179	.init = nvkm_timer_init,
180	.fini = nvkm_timer_fini,
181	.intr = nvkm_timer_intr,
182};
183
184int
185nvkm_timer_new_(const struct nvkm_timer_func *func, struct nvkm_device *device,
186		enum nvkm_subdev_type type, int inst, struct nvkm_timer **ptmr)
187{
188	struct nvkm_timer *tmr;
189
190	if (!(tmr = *ptmr = kzalloc(sizeof(*tmr), GFP_KERNEL)))
191		return -ENOMEM;
192
193	nvkm_subdev_ctor(&nvkm_timer, device, type, inst, &tmr->subdev);
194	tmr->func = func;
195	INIT_LIST_HEAD(&tmr->alarms);
196	spin_lock_init(&tmr->lock);
197	return 0;
198}
199