xref: /openbmc/linux/drivers/gpu/host1x/syncpt.c (revision e23feb16)
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 
33 static struct host1x_syncpt *_host1x_syncpt_alloc(struct host1x *host,
34 						  struct device *dev,
35 						  bool client_managed)
36 {
37 	int i;
38 	struct host1x_syncpt *sp = host->syncpt;
39 	char *name;
40 
41 	for (i = 0; i < host->info->nb_pts && sp->name; i++, sp++)
42 		;
43 
44 	if (i >= host->info->nb_pts)
45 		return NULL;
46 
47 	name = kasprintf(GFP_KERNEL, "%02d-%s", sp->id,
48 			dev ? dev_name(dev) : NULL);
49 	if (!name)
50 		return NULL;
51 
52 	sp->dev = dev;
53 	sp->name = name;
54 	sp->client_managed = client_managed;
55 
56 	return sp;
57 }
58 
59 u32 host1x_syncpt_id(struct host1x_syncpt *sp)
60 {
61 	return sp->id;
62 }
63 
64 /*
65  * Updates the value sent to hardware.
66  */
67 u32 host1x_syncpt_incr_max(struct host1x_syncpt *sp, u32 incrs)
68 {
69 	return (u32)atomic_add_return(incrs, &sp->max_val);
70 }
71 
72  /*
73  * Write cached syncpoint and waitbase values to hardware.
74  */
75 void host1x_syncpt_restore(struct host1x *host)
76 {
77 	struct host1x_syncpt *sp_base = host->syncpt;
78 	u32 i;
79 
80 	for (i = 0; i < host1x_syncpt_nb_pts(host); i++)
81 		host1x_hw_syncpt_restore(host, sp_base + i);
82 	for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
83 		host1x_hw_syncpt_restore_wait_base(host, sp_base + i);
84 	wmb();
85 }
86 
87 /*
88  * Update the cached syncpoint and waitbase values by reading them
89  * from the registers.
90   */
91 void host1x_syncpt_save(struct host1x *host)
92 {
93 	struct host1x_syncpt *sp_base = host->syncpt;
94 	u32 i;
95 
96 	for (i = 0; i < host1x_syncpt_nb_pts(host); i++) {
97 		if (host1x_syncpt_client_managed(sp_base + i))
98 			host1x_hw_syncpt_load(host, sp_base + i);
99 		else
100 			WARN_ON(!host1x_syncpt_idle(sp_base + i));
101 	}
102 
103 	for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
104 		host1x_hw_syncpt_load_wait_base(host, sp_base + i);
105 }
106 
107 /*
108  * Updates the cached syncpoint value by reading a new value from the hardware
109  * register
110  */
111 u32 host1x_syncpt_load(struct host1x_syncpt *sp)
112 {
113 	u32 val;
114 	val = host1x_hw_syncpt_load(sp->host, sp);
115 	trace_host1x_syncpt_load_min(sp->id, val);
116 
117 	return val;
118 }
119 
120 /*
121  * Get the current syncpoint base
122  */
123 u32 host1x_syncpt_load_wait_base(struct host1x_syncpt *sp)
124 {
125 	u32 val;
126 	host1x_hw_syncpt_load_wait_base(sp->host, sp);
127 	val = sp->base_val;
128 	return val;
129 }
130 
131 /*
132  * Increment syncpoint value from cpu, updating cache
133  */
134 int host1x_syncpt_incr(struct host1x_syncpt *sp)
135 {
136 	return host1x_hw_syncpt_cpu_incr(sp->host, sp);
137 }
138 
139 /*
140  * Updated sync point form hardware, and returns true if syncpoint is expired,
141  * false if we may need to wait
142  */
143 static bool syncpt_load_min_is_expired(struct host1x_syncpt *sp, u32 thresh)
144 {
145 	host1x_hw_syncpt_load(sp->host, sp);
146 	return host1x_syncpt_is_expired(sp, thresh);
147 }
148 
149 /*
150  * Main entrypoint for syncpoint value waits.
151  */
152 int host1x_syncpt_wait(struct host1x_syncpt *sp, u32 thresh, long timeout,
153 			u32 *value)
154 {
155 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
156 	void *ref;
157 	struct host1x_waitlist *waiter;
158 	int err = 0, check_count = 0;
159 	u32 val;
160 
161 	if (value)
162 		*value = 0;
163 
164 	/* first check cache */
165 	if (host1x_syncpt_is_expired(sp, thresh)) {
166 		if (value)
167 			*value = host1x_syncpt_load(sp);
168 		return 0;
169 	}
170 
171 	/* try to read from register */
172 	val = host1x_hw_syncpt_load(sp->host, sp);
173 	if (host1x_syncpt_is_expired(sp, thresh)) {
174 		if (value)
175 			*value = val;
176 		goto done;
177 	}
178 
179 	if (!timeout) {
180 		err = -EAGAIN;
181 		goto done;
182 	}
183 
184 	/* allocate a waiter */
185 	waiter = kzalloc(sizeof(*waiter), GFP_KERNEL);
186 	if (!waiter) {
187 		err = -ENOMEM;
188 		goto done;
189 	}
190 
191 	/* schedule a wakeup when the syncpoint value is reached */
192 	err = host1x_intr_add_action(sp->host, sp->id, thresh,
193 				     HOST1X_INTR_ACTION_WAKEUP_INTERRUPTIBLE,
194 				     &wq, waiter, &ref);
195 	if (err)
196 		goto done;
197 
198 	err = -EAGAIN;
199 	/* Caller-specified timeout may be impractically low */
200 	if (timeout < 0)
201 		timeout = LONG_MAX;
202 
203 	/* wait for the syncpoint, or timeout, or signal */
204 	while (timeout) {
205 		long check = min_t(long, SYNCPT_CHECK_PERIOD, timeout);
206 		int remain = wait_event_interruptible_timeout(wq,
207 				syncpt_load_min_is_expired(sp, thresh),
208 				check);
209 		if (remain > 0 || host1x_syncpt_is_expired(sp, thresh)) {
210 			if (value)
211 				*value = host1x_syncpt_load(sp);
212 			err = 0;
213 			break;
214 		}
215 		if (remain < 0) {
216 			err = remain;
217 			break;
218 		}
219 		timeout -= check;
220 		if (timeout && check_count <= MAX_STUCK_CHECK_COUNT) {
221 			dev_warn(sp->host->dev,
222 				"%s: syncpoint id %d (%s) stuck waiting %d, timeout=%ld\n",
223 				 current->comm, sp->id, sp->name,
224 				 thresh, timeout);
225 
226 			host1x_debug_dump_syncpts(sp->host);
227 			if (check_count == MAX_STUCK_CHECK_COUNT)
228 				host1x_debug_dump(sp->host);
229 			check_count++;
230 		}
231 	}
232 	host1x_intr_put_ref(sp->host, sp->id, ref);
233 
234 done:
235 	return err;
236 }
237 EXPORT_SYMBOL(host1x_syncpt_wait);
238 
239 /*
240  * Returns true if syncpoint is expired, false if we may need to wait
241  */
242 bool host1x_syncpt_is_expired(struct host1x_syncpt *sp, u32 thresh)
243 {
244 	u32 current_val;
245 	u32 future_val;
246 	smp_rmb();
247 	current_val = (u32)atomic_read(&sp->min_val);
248 	future_val = (u32)atomic_read(&sp->max_val);
249 
250 	/* Note the use of unsigned arithmetic here (mod 1<<32).
251 	 *
252 	 * c = current_val = min_val	= the current value of the syncpoint.
253 	 * t = thresh			= the value we are checking
254 	 * f = future_val  = max_val	= the value c will reach when all
255 	 *				  outstanding increments have completed.
256 	 *
257 	 * Note that c always chases f until it reaches f.
258 	 *
259 	 * Dtf = (f - t)
260 	 * Dtc = (c - t)
261 	 *
262 	 *  Consider all cases:
263 	 *
264 	 *	A) .....c..t..f.....	Dtf < Dtc	need to wait
265 	 *	B) .....c.....f..t..	Dtf > Dtc	expired
266 	 *	C) ..t..c.....f.....	Dtf > Dtc	expired	   (Dct very large)
267 	 *
268 	 *  Any case where f==c: always expired (for any t).	Dtf == Dcf
269 	 *  Any case where t==c: always expired (for any f).	Dtf >= Dtc (because Dtc==0)
270 	 *  Any case where t==f!=c: always wait.		Dtf <  Dtc (because Dtf==0,
271 	 *							Dtc!=0)
272 	 *
273 	 *  Other cases:
274 	 *
275 	 *	A) .....t..f..c.....	Dtf < Dtc	need to wait
276 	 *	A) .....f..c..t.....	Dtf < Dtc	need to wait
277 	 *	A) .....f..t..c.....	Dtf > Dtc	expired
278 	 *
279 	 *   So:
280 	 *	   Dtf >= Dtc implies EXPIRED	(return true)
281 	 *	   Dtf <  Dtc implies WAIT	(return false)
282 	 *
283 	 * Note: If t is expired then we *cannot* wait on it. We would wait
284 	 * forever (hang the system).
285 	 *
286 	 * Note: do NOT get clever and remove the -thresh from both sides. It
287 	 * is NOT the same.
288 	 *
289 	 * If future valueis zero, we have a client managed sync point. In that
290 	 * case we do a direct comparison.
291 	 */
292 	if (!host1x_syncpt_client_managed(sp))
293 		return future_val - thresh >= current_val - thresh;
294 	else
295 		return (s32)(current_val - thresh) >= 0;
296 }
297 
298 /* remove a wait pointed to by patch_addr */
299 int host1x_syncpt_patch_wait(struct host1x_syncpt *sp, void *patch_addr)
300 {
301 	return host1x_hw_syncpt_patch_wait(sp->host, sp, patch_addr);
302 }
303 
304 int host1x_syncpt_init(struct host1x *host)
305 {
306 	struct host1x_syncpt *syncpt;
307 	int i;
308 
309 	syncpt = devm_kzalloc(host->dev, sizeof(*syncpt) * host->info->nb_pts,
310 		GFP_KERNEL);
311 	if (!syncpt)
312 		return -ENOMEM;
313 
314 	for (i = 0; i < host->info->nb_pts; ++i) {
315 		syncpt[i].id = i;
316 		syncpt[i].host = host;
317 	}
318 
319 	host->syncpt = syncpt;
320 
321 	host1x_syncpt_restore(host);
322 
323 	/* Allocate sync point to use for clearing waits for expired fences */
324 	host->nop_sp = _host1x_syncpt_alloc(host, NULL, false);
325 	if (!host->nop_sp)
326 		return -ENOMEM;
327 
328 	return 0;
329 }
330 
331 struct host1x_syncpt *host1x_syncpt_request(struct device *dev,
332 					    bool client_managed)
333 {
334 	struct host1x *host = dev_get_drvdata(dev->parent);
335 	return _host1x_syncpt_alloc(host, dev, client_managed);
336 }
337 
338 void host1x_syncpt_free(struct host1x_syncpt *sp)
339 {
340 	if (!sp)
341 		return;
342 
343 	kfree(sp->name);
344 	sp->dev = NULL;
345 	sp->name = NULL;
346 	sp->client_managed = false;
347 }
348 
349 void host1x_syncpt_deinit(struct host1x *host)
350 {
351 	int i;
352 	struct host1x_syncpt *sp = host->syncpt;
353 	for (i = 0; i < host->info->nb_pts; i++, sp++)
354 		kfree(sp->name);
355 }
356 
357 int host1x_syncpt_nb_pts(struct host1x *host)
358 {
359 	return host->info->nb_pts;
360 }
361 
362 int host1x_syncpt_nb_bases(struct host1x *host)
363 {
364 	return host->info->nb_bases;
365 }
366 
367 int host1x_syncpt_nb_mlocks(struct host1x *host)
368 {
369 	return host->info->nb_mlocks;
370 }
371 
372 struct host1x_syncpt *host1x_syncpt_get(struct host1x *host, u32 id)
373 {
374 	if (host->info->nb_pts < id)
375 		return NULL;
376 	return host->syncpt + id;
377 }
378