1/*
2 * Tegra host1x Syncpoints
3 *
4 * Copyright (c) 2010-2013, NVIDIA Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
17 */
18
19#include <linux/module.h>
20#include <linux/device.h>
21#include <linux/slab.h>
22
23#include <trace/events/host1x.h>
24
25#include "syncpt.h"
26#include "dev.h"
27#include "intr.h"
28#include "debug.h"
29
30#define SYNCPT_CHECK_PERIOD (2 * HZ)
31#define MAX_STUCK_CHECK_COUNT 15
32
33static struct host1x_syncpt_base *
34host1x_syncpt_base_request(struct host1x *host)
35{
36	struct host1x_syncpt_base *bases = host->bases;
37	unsigned int i;
38
39	for (i = 0; i < host->info->nb_bases; i++)
40		if (!bases[i].requested)
41			break;
42
43	if (i >= host->info->nb_bases)
44		return NULL;
45
46	bases[i].requested = true;
47	return &bases[i];
48}
49
50static void host1x_syncpt_base_free(struct host1x_syncpt_base *base)
51{
52	if (base)
53		base->requested = false;
54}
55
56static struct host1x_syncpt *host1x_syncpt_alloc(struct host1x *host,
57						 struct device *dev,
58						 unsigned long flags)
59{
60	int i;
61	struct host1x_syncpt *sp = host->syncpt;
62	char *name;
63
64	for (i = 0; i < host->info->nb_pts && sp->name; i++, sp++)
65		;
66
67	if (i >= host->info->nb_pts)
68		return NULL;
69
70	if (flags & HOST1X_SYNCPT_HAS_BASE) {
71		sp->base = host1x_syncpt_base_request(host);
72		if (!sp->base)
73			return NULL;
74	}
75
76	name = kasprintf(GFP_KERNEL, "%02d-%s", sp->id,
77			dev ? dev_name(dev) : NULL);
78	if (!name)
79		return NULL;
80
81	sp->dev = dev;
82	sp->name = name;
83
84	if (flags & HOST1X_SYNCPT_CLIENT_MANAGED)
85		sp->client_managed = true;
86	else
87		sp->client_managed = false;
88
89	return sp;
90}
91
92u32 host1x_syncpt_id(struct host1x_syncpt *sp)
93{
94	return sp->id;
95}
96EXPORT_SYMBOL(host1x_syncpt_id);
97
98/*
99 * Updates the value sent to hardware.
100 */
101u32 host1x_syncpt_incr_max(struct host1x_syncpt *sp, u32 incrs)
102{
103	return (u32)atomic_add_return(incrs, &sp->max_val);
104}
105EXPORT_SYMBOL(host1x_syncpt_incr_max);
106
107 /*
108 * Write cached syncpoint and waitbase values to hardware.
109 */
110void host1x_syncpt_restore(struct host1x *host)
111{
112	struct host1x_syncpt *sp_base = host->syncpt;
113	u32 i;
114
115	for (i = 0; i < host1x_syncpt_nb_pts(host); i++)
116		host1x_hw_syncpt_restore(host, sp_base + i);
117	for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
118		host1x_hw_syncpt_restore_wait_base(host, sp_base + i);
119	wmb();
120}
121
122/*
123 * Update the cached syncpoint and waitbase values by reading them
124 * from the registers.
125  */
126void host1x_syncpt_save(struct host1x *host)
127{
128	struct host1x_syncpt *sp_base = host->syncpt;
129	u32 i;
130
131	for (i = 0; i < host1x_syncpt_nb_pts(host); i++) {
132		if (host1x_syncpt_client_managed(sp_base + i))
133			host1x_hw_syncpt_load(host, sp_base + i);
134		else
135			WARN_ON(!host1x_syncpt_idle(sp_base + i));
136	}
137
138	for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
139		host1x_hw_syncpt_load_wait_base(host, sp_base + i);
140}
141
142/*
143 * Updates the cached syncpoint value by reading a new value from the hardware
144 * register
145 */
146u32 host1x_syncpt_load(struct host1x_syncpt *sp)
147{
148	u32 val;
149	val = host1x_hw_syncpt_load(sp->host, sp);
150	trace_host1x_syncpt_load_min(sp->id, val);
151
152	return val;
153}
154
155/*
156 * Get the current syncpoint base
157 */
158u32 host1x_syncpt_load_wait_base(struct host1x_syncpt *sp)
159{
160	u32 val;
161	host1x_hw_syncpt_load_wait_base(sp->host, sp);
162	val = sp->base_val;
163	return val;
164}
165
166/*
167 * Increment syncpoint value from cpu, updating cache
168 */
169int host1x_syncpt_incr(struct host1x_syncpt *sp)
170{
171	return host1x_hw_syncpt_cpu_incr(sp->host, sp);
172}
173EXPORT_SYMBOL(host1x_syncpt_incr);
174
175/*
176 * Updated sync point form hardware, and returns true if syncpoint is expired,
177 * false if we may need to wait
178 */
179static bool syncpt_load_min_is_expired(struct host1x_syncpt *sp, u32 thresh)
180{
181	host1x_hw_syncpt_load(sp->host, sp);
182	return host1x_syncpt_is_expired(sp, thresh);
183}
184
185/*
186 * Main entrypoint for syncpoint value waits.
187 */
188int host1x_syncpt_wait(struct host1x_syncpt *sp, u32 thresh, long timeout,
189			u32 *value)
190{
191	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
192	void *ref;
193	struct host1x_waitlist *waiter;
194	int err = 0, check_count = 0;
195	u32 val;
196
197	if (value)
198		*value = 0;
199
200	/* first check cache */
201	if (host1x_syncpt_is_expired(sp, thresh)) {
202		if (value)
203			*value = host1x_syncpt_load(sp);
204		return 0;
205	}
206
207	/* try to read from register */
208	val = host1x_hw_syncpt_load(sp->host, sp);
209	if (host1x_syncpt_is_expired(sp, thresh)) {
210		if (value)
211			*value = val;
212		goto done;
213	}
214
215	if (!timeout) {
216		err = -EAGAIN;
217		goto done;
218	}
219
220	/* allocate a waiter */
221	waiter = kzalloc(sizeof(*waiter), GFP_KERNEL);
222	if (!waiter) {
223		err = -ENOMEM;
224		goto done;
225	}
226
227	/* schedule a wakeup when the syncpoint value is reached */
228	err = host1x_intr_add_action(sp->host, sp->id, thresh,
229				     HOST1X_INTR_ACTION_WAKEUP_INTERRUPTIBLE,
230				     &wq, waiter, &ref);
231	if (err)
232		goto done;
233
234	err = -EAGAIN;
235	/* Caller-specified timeout may be impractically low */
236	if (timeout < 0)
237		timeout = LONG_MAX;
238
239	/* wait for the syncpoint, or timeout, or signal */
240	while (timeout) {
241		long check = min_t(long, SYNCPT_CHECK_PERIOD, timeout);
242		int remain = wait_event_interruptible_timeout(wq,
243				syncpt_load_min_is_expired(sp, thresh),
244				check);
245		if (remain > 0 || host1x_syncpt_is_expired(sp, thresh)) {
246			if (value)
247				*value = host1x_syncpt_load(sp);
248			err = 0;
249			break;
250		}
251		if (remain < 0) {
252			err = remain;
253			break;
254		}
255		timeout -= check;
256		if (timeout && check_count <= MAX_STUCK_CHECK_COUNT) {
257			dev_warn(sp->host->dev,
258				"%s: syncpoint id %d (%s) stuck waiting %d, timeout=%ld\n",
259				 current->comm, sp->id, sp->name,
260				 thresh, timeout);
261
262			host1x_debug_dump_syncpts(sp->host);
263			if (check_count == MAX_STUCK_CHECK_COUNT)
264				host1x_debug_dump(sp->host);
265			check_count++;
266		}
267	}
268	host1x_intr_put_ref(sp->host, sp->id, ref);
269
270done:
271	return err;
272}
273EXPORT_SYMBOL(host1x_syncpt_wait);
274
275/*
276 * Returns true if syncpoint is expired, false if we may need to wait
277 */
278bool host1x_syncpt_is_expired(struct host1x_syncpt *sp, u32 thresh)
279{
280	u32 current_val;
281	u32 future_val;
282	smp_rmb();
283	current_val = (u32)atomic_read(&sp->min_val);
284	future_val = (u32)atomic_read(&sp->max_val);
285
286	/* Note the use of unsigned arithmetic here (mod 1<<32).
287	 *
288	 * c = current_val = min_val	= the current value of the syncpoint.
289	 * t = thresh			= the value we are checking
290	 * f = future_val  = max_val	= the value c will reach when all
291	 *				  outstanding increments have completed.
292	 *
293	 * Note that c always chases f until it reaches f.
294	 *
295	 * Dtf = (f - t)
296	 * Dtc = (c - t)
297	 *
298	 *  Consider all cases:
299	 *
300	 *	A) .....c..t..f.....	Dtf < Dtc	need to wait
301	 *	B) .....c.....f..t..	Dtf > Dtc	expired
302	 *	C) ..t..c.....f.....	Dtf > Dtc	expired	   (Dct very large)
303	 *
304	 *  Any case where f==c: always expired (for any t).	Dtf == Dcf
305	 *  Any case where t==c: always expired (for any f).	Dtf >= Dtc (because Dtc==0)
306	 *  Any case where t==f!=c: always wait.		Dtf <  Dtc (because Dtf==0,
307	 *							Dtc!=0)
308	 *
309	 *  Other cases:
310	 *
311	 *	A) .....t..f..c.....	Dtf < Dtc	need to wait
312	 *	A) .....f..c..t.....	Dtf < Dtc	need to wait
313	 *	A) .....f..t..c.....	Dtf > Dtc	expired
314	 *
315	 *   So:
316	 *	   Dtf >= Dtc implies EXPIRED	(return true)
317	 *	   Dtf <  Dtc implies WAIT	(return false)
318	 *
319	 * Note: If t is expired then we *cannot* wait on it. We would wait
320	 * forever (hang the system).
321	 *
322	 * Note: do NOT get clever and remove the -thresh from both sides. It
323	 * is NOT the same.
324	 *
325	 * If future valueis zero, we have a client managed sync point. In that
326	 * case we do a direct comparison.
327	 */
328	if (!host1x_syncpt_client_managed(sp))
329		return future_val - thresh >= current_val - thresh;
330	else
331		return (s32)(current_val - thresh) >= 0;
332}
333
334/* remove a wait pointed to by patch_addr */
335int host1x_syncpt_patch_wait(struct host1x_syncpt *sp, void *patch_addr)
336{
337	return host1x_hw_syncpt_patch_wait(sp->host, sp, patch_addr);
338}
339
340int host1x_syncpt_init(struct host1x *host)
341{
342	struct host1x_syncpt_base *bases;
343	struct host1x_syncpt *syncpt;
344	int i;
345
346	syncpt = devm_kzalloc(host->dev, sizeof(*syncpt) * host->info->nb_pts,
347			      GFP_KERNEL);
348	if (!syncpt)
349		return -ENOMEM;
350
351	bases = devm_kzalloc(host->dev, sizeof(*bases) * host->info->nb_bases,
352			     GFP_KERNEL);
353	if (!bases)
354		return -ENOMEM;
355
356	for (i = 0; i < host->info->nb_pts; i++) {
357		syncpt[i].id = i;
358		syncpt[i].host = host;
359	}
360
361	for (i = 0; i < host->info->nb_bases; i++)
362		bases[i].id = i;
363
364	host->syncpt = syncpt;
365	host->bases = bases;
366
367	host1x_syncpt_restore(host);
368
369	/* Allocate sync point to use for clearing waits for expired fences */
370	host->nop_sp = host1x_syncpt_alloc(host, NULL, 0);
371	if (!host->nop_sp)
372		return -ENOMEM;
373
374	return 0;
375}
376
377struct host1x_syncpt *host1x_syncpt_request(struct device *dev,
378					    unsigned long flags)
379{
380	struct host1x *host = dev_get_drvdata(dev->parent);
381	return host1x_syncpt_alloc(host, dev, flags);
382}
383EXPORT_SYMBOL(host1x_syncpt_request);
384
385void host1x_syncpt_free(struct host1x_syncpt *sp)
386{
387	if (!sp)
388		return;
389
390	host1x_syncpt_base_free(sp->base);
391	kfree(sp->name);
392	sp->base = NULL;
393	sp->dev = NULL;
394	sp->name = NULL;
395	sp->client_managed = false;
396}
397EXPORT_SYMBOL(host1x_syncpt_free);
398
399void host1x_syncpt_deinit(struct host1x *host)
400{
401	int i;
402	struct host1x_syncpt *sp = host->syncpt;
403	for (i = 0; i < host->info->nb_pts; i++, sp++)
404		kfree(sp->name);
405}
406
407/*
408 * Read max. It indicates how many operations there are in queue, either in
409 * channel or in a software thread.
410 * */
411u32 host1x_syncpt_read_max(struct host1x_syncpt *sp)
412{
413	smp_rmb();
414	return (u32)atomic_read(&sp->max_val);
415}
416EXPORT_SYMBOL(host1x_syncpt_read_max);
417
418/*
419 * Read min, which is a shadow of the current sync point value in hardware.
420 */
421u32 host1x_syncpt_read_min(struct host1x_syncpt *sp)
422{
423	smp_rmb();
424	return (u32)atomic_read(&sp->min_val);
425}
426EXPORT_SYMBOL(host1x_syncpt_read_min);
427
428u32 host1x_syncpt_read(struct host1x_syncpt *sp)
429{
430	return host1x_syncpt_load(sp);
431}
432EXPORT_SYMBOL(host1x_syncpt_read);
433
434int host1x_syncpt_nb_pts(struct host1x *host)
435{
436	return host->info->nb_pts;
437}
438
439int host1x_syncpt_nb_bases(struct host1x *host)
440{
441	return host->info->nb_bases;
442}
443
444int host1x_syncpt_nb_mlocks(struct host1x *host)
445{
446	return host->info->nb_mlocks;
447}
448
449struct host1x_syncpt *host1x_syncpt_get(struct host1x *host, u32 id)
450{
451	if (host->info->nb_pts < id)
452		return NULL;
453	return host->syncpt + id;
454}
455EXPORT_SYMBOL(host1x_syncpt_get);
456
457struct host1x_syncpt_base *host1x_syncpt_get_base(struct host1x_syncpt *sp)
458{
459	return sp ? sp->base : NULL;
460}
461EXPORT_SYMBOL(host1x_syncpt_get_base);
462
463u32 host1x_syncpt_base_id(struct host1x_syncpt_base *base)
464{
465	return base->id;
466}
467EXPORT_SYMBOL(host1x_syncpt_base_id);
468