summaryrefslogtreecommitdiffstats
path: root/arch/arm/mach-omap2/clockdomain.c
blob: 50c8cd7c71267c147adfbeb870e2a01d4d1ecdb9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
/*
 * OMAP2/3 clockdomain framework functions
 *
 * Copyright (C) 2008 Texas Instruments, Inc.
 * Copyright (C) 2008-2009 Nokia Corporation
 *
 * Written by Paul Walmsley and Jouni Högander
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#undef DEBUG

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/limits.h>
#include <linux/err.h>

#include <linux/io.h>

#include <linux/bitops.h>

#include <plat/clock.h>

#include "prm.h"
#include "prm-regbits-24xx.h"
#include "cm.h"

#include <plat/powerdomain.h>
#include <plat/clockdomain.h>

/* clkdm_list contains all registered struct clockdomains */
static LIST_HEAD(clkdm_list);

/* clkdm_mutex protects clkdm_list add and del ops */
static DEFINE_MUTEX(clkdm_mutex);

/* array of powerdomain deps to be added/removed when clkdm in hwsup mode */
static struct clkdm_pwrdm_autodep *autodeps;


/* Private functions */

/*
 * _autodep_lookup - resolve autodep pwrdm names to pwrdm pointers; store
 * @autodep: struct clkdm_pwrdm_autodep * to resolve
 *
 * Resolve autodep powerdomain names to powerdomain pointers via
 * pwrdm_lookup() and store the pointers in the autodep structure.  An
 * "autodep" is a powerdomain sleep/wakeup dependency that is
 * automatically added and removed whenever clocks in the associated
 * clockdomain are enabled or disabled (respectively) when the
 * clockdomain is in hardware-supervised mode.	Meant to be called
 * once at clockdomain layer initialization, since these should remain
 * fixed for a particular architecture.  No return value.
 */
static void _autodep_lookup(struct clkdm_pwrdm_autodep *autodep)
{
	struct powerdomain *pwrdm;

	if (!autodep)
		return;

	if (!omap_chip_is(autodep->omap_chip))
		return;

	pwrdm = pwrdm_lookup(autodep->pwrdm.name);
	if (!pwrdm) {
		pr_err("clockdomain: autodeps: powerdomain %s does not exist\n",
			 autodep->pwrdm.name);
		pwrdm = ERR_PTR(-ENOENT);
	}
	autodep->pwrdm.ptr = pwrdm;
}

/*
 * _clkdm_add_autodeps - add auto sleepdeps/wkdeps to clkdm upon clock enable
 * @clkdm: struct clockdomain *
 *
 * Add the "autodep" sleep & wakeup dependencies to clockdomain 'clkdm'
 * in hardware-supervised mode.  Meant to be called from clock framework
 * when a clock inside clockdomain 'clkdm' is enabled.	No return value.
 */
static void _clkdm_add_autodeps(struct clockdomain *clkdm)
{
	struct clkdm_pwrdm_autodep *autodep;

	for (autodep = autodeps; autodep->pwrdm.ptr; autodep++) {
		if (IS_ERR(autodep->pwrdm.ptr))
			continue;

		if (!omap_chip_is(autodep->omap_chip))
			continue;

		pr_debug("clockdomain: adding %s sleepdep/wkdep for "
			 "pwrdm %s\n", autodep->pwrdm.ptr->name,
			 clkdm->pwrdm.ptr->name);

		pwrdm_add_sleepdep(clkdm->pwrdm.ptr, autodep->pwrdm.ptr);
		pwrdm_add_wkdep(clkdm->pwrdm.ptr, autodep->pwrdm.ptr);
	}
}

/*
 * _clkdm_add_autodeps - remove auto sleepdeps/wkdeps from clkdm
 * @clkdm: struct clockdomain *
 *
 * Remove the "autodep" sleep & wakeup dependencies from clockdomain 'clkdm'
 * in hardware-supervised mode.  Meant to be called from clock framework
 * when a clock inside clockdomain 'clkdm' is disabled.  No return value.
 */
static void _clkdm_del_autodeps(struct clockdomain *clkdm)
{
	struct clkdm_pwrdm_autodep *autodep;

	for (autodep = autodeps; autodep->pwrdm.ptr; autodep++) {
		if (IS_ERR(autodep->pwrdm.ptr))
			continue;

		if (!omap_chip_is(autodep->omap_chip))
			continue;

		pr_debug("clockdomain: removing %s sleepdep/wkdep for "
			 "pwrdm %s\n", autodep->pwrdm.ptr->name,
			 clkdm->pwrdm.ptr->name);

		pwrdm_del_sleepdep(clkdm->pwrdm.ptr, autodep->pwrdm.ptr);
		pwrdm_del_wkdep(clkdm->pwrdm.ptr, autodep->pwrdm.ptr);
	}
}

/*
 * _omap2_clkdm_set_hwsup - set the hwsup idle transition bit
 * @clkdm: struct clockdomain *
 * @enable: int 0 to disable, 1 to enable
 *
 * Internal helper for actually switching the bit that controls hwsup
 * idle transitions for clkdm.
 */
static void _omap2_clkdm_set_hwsup(struct clockdomain *clkdm, int enable)
{
	u32 v;

	if (cpu_is_omap24xx()) {
		if (enable)
			v = OMAP24XX_CLKSTCTRL_ENABLE_AUTO;
		else
			v = OMAP24XX_CLKSTCTRL_DISABLE_AUTO;
	} else if (cpu_is_omap34xx()) {
		if (enable)
			v = OMAP34XX_CLKSTCTRL_ENABLE_AUTO;
		else
			v = OMAP34XX_CLKSTCTRL_DISABLE_AUTO;
	} else {
		BUG();
	}

	cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask,
			    v << __ffs(clkdm->clktrctrl_mask),
			    clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL);
}

static struct clockdomain *_clkdm_lookup(const char *name)
{
	struct clockdomain *clkdm, *temp_clkdm;

	if (!name)
		return NULL;

	clkdm = NULL;

	list_for_each_entry(temp_clkdm, &clkdm_list, node) {
		if (!strcmp(name, temp_clkdm->name)) {
			clkdm = temp_clkdm;
			break;
		}
	}

	return clkdm;
}


/* Public functions */

/**
 * clkdm_init - set up the clockdomain layer
 * @clkdms: optional pointer to an array of clockdomains to register
 * @init_autodeps: optional pointer to an array of autodeps to register
 *
 * Set up internal state.  If a pointer to an array of clockdomains
 * was supplied, loop through the list of clockdomains, register all
 * that are available on the current platform.	Similarly, if a
 * pointer to an array of clockdomain-powerdomain autodependencies was
 * provided, register those.  No return value.
 */
void clkdm_init(struct clockdomain **clkdms,
		struct clkdm_pwrdm_autodep *init_autodeps)
{
	struct clockdomain **c = NULL;
	struct clkdm_pwrdm_autodep *autodep = NULL;

	if (clkdms)
		for (c = clkdms; *c; c++)
			clkdm_register(*c);

	autodeps = init_autodeps;
	if (autodeps)
		for (autodep = autodeps; autodep->pwrdm.ptr; autodep++)
			_autodep_lookup(autodep);
}

/**
 * clkdm_register - register a clockdomain
 * @clkdm: struct clockdomain * to register
 *
 * Adds a clockdomain to the internal clockdomain list.
 * Returns -EINVAL if given a null pointer, -EEXIST if a clockdomain is
 * already registered by the provided name, or 0 upon success.
 */
int clkdm_register(struct clockdomain *clkdm)
{
	int ret = -EINVAL;
	struct powerdomain *pwrdm;

	if (!clkdm || !clkdm->name)
		return -EINVAL;

	if (!omap_chip_is(clkdm->omap_chip))
		return -EINVAL;

	pwrdm = pwrdm_lookup(clkdm->pwrdm.name);
	if (!pwrdm) {
		pr_err("clockdomain: %s: powerdomain %s does not exist\n",
			clkdm->name, clkdm->pwrdm.name);
		return -EINVAL;
	}
	clkdm->pwrdm.ptr = pwrdm;

	mutex_lock(&clkdm_mutex);
	/* Verify that the clockdomain is not already registered */
	if (_clkdm_lookup(clkdm->name)) {
		ret = -EEXIST;
		goto cr_unlock;
	}

	list_add(&clkdm->node, &clkdm_list);

	pwrdm_add_clkdm(pwrdm, clkdm);

	pr_debug("clockdomain: registered %s\n", clkdm->name);
	ret = 0;

cr_unlock:
	mutex_unlock(&clkdm_mutex);

	return ret;
}

/**
 * clkdm_unregister - unregister a clockdomain
 * @clkdm: struct clockdomain * to unregister
 *
 * Removes a clockdomain from the internal clockdomain list.  Returns
 * -EINVAL if clkdm argument is NULL.
 */
int clkdm_unregister(struct clockdomain *clkdm)
{
	if (!clkdm)
		return -EINVAL;

	pwrdm_del_clkdm(clkdm->pwrdm.ptr, clkdm);

	mutex_lock(&clkdm_mutex);
	list_del(&clkdm->node);
	mutex_unlock(&clkdm_mutex);

	pr_debug("clockdomain: unregistered %s\n", clkdm->name);

	return 0;
}

/**
 * clkdm_lookup - look up a clockdomain by name, return a pointer
 * @name: name of clockdomain
 *
 * Find a registered clockdomain by its name.  Returns a pointer to the
 * struct clockdomain if found, or NULL otherwise.
 */
struct clockdomain *clkdm_lookup(const char *name)
{
	struct clockdomain *clkdm, *temp_clkdm;

	if (!name)
		return NULL;

	clkdm = NULL;

	mutex_lock(&clkdm_mutex);
	list_for_each_entry(temp_clkdm, &clkdm_list, node) {
		if (!strcmp(name, temp_clkdm->name)) {
			clkdm = temp_clkdm;
			break;
		}
	}
	mutex_unlock(&clkdm_mutex);

	return clkdm;
}

/**
 * clkdm_for_each - call function on each registered clockdomain
 * @fn: callback function *
 *
 * Call the supplied function for each registered clockdomain.
 * The callback function can return anything but 0 to bail
 * out early from the iterator.  The callback function is called with
 * the clkdm_mutex held, so no clockdomain structure manipulation
 * functions should be called from the callback, although hardware
 * clockdomain control functions are fine.  Returns the last return
 * value of the callback function, which should be 0 for success or
 * anything else to indicate failure; or -EINVAL if the function pointer
 * is null.
 */
int clkdm_for_each(int (*fn)(struct clockdomain *clkdm, void *user),
			void *user)
{
	struct clockdomain *clkdm;
	int ret = 0;

	if (!fn)
		return -EINVAL;

	mutex_lock(&clkdm_mutex);
	list_for_each_entry(clkdm, &clkdm_list, node) {
		ret = (*fn)(clkdm, user);
		if (ret)
			break;
	}
	mutex_unlock(&clkdm_mutex);

	return ret;
}


/**
 * clkdm_get_pwrdm - return a ptr to the pwrdm that this clkdm resides in
 * @clkdm: struct clockdomain *
 *
 * Return a pointer to the struct powerdomain that the specified clockdomain
 * 'clkdm' exists in, or returns NULL if clkdm argument is NULL.
 */
struct powerdomain *clkdm_get_pwrdm(struct clockdomain *clkdm)
{
	if (!clkdm)
		return NULL;

	return clkdm->pwrdm.ptr;
}


/* Hardware clockdomain control */

/**
 * omap2_clkdm_clktrctrl_read - read the clkdm's current state transition mode
 * @clk: struct clk * of a clockdomain
 *
 * Return the clockdomain's current state transition mode from the
 * corresponding domain CM_CLKSTCTRL register.	Returns -EINVAL if clk
 * is NULL or the current mode upon success.
 */
static int omap2_clkdm_clktrctrl_read(struct clockdomain *clkdm)
{
	u32 v;

	if (!clkdm)
		return -EINVAL;

	v = cm_read_mod_reg(clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL);
	v &= clkdm->clktrctrl_mask;
	v >>= __ffs(clkdm->clktrctrl_mask);

	return v;
}

/**
 * omap2_clkdm_sleep - force clockdomain sleep transition
 * @clkdm: struct clockdomain *
 *
 * Instruct the CM to force a sleep transition on the specified
 * clockdomain 'clkdm'.  Returns -EINVAL if clk is NULL or if
 * clockdomain does not support software-initiated sleep; 0 upon
 * success.
 */
int omap2_clkdm_sleep(struct clockdomain *clkdm)
{
	if (!clkdm)
		return -EINVAL;

	if (!(clkdm->flags & CLKDM_CAN_FORCE_SLEEP)) {
		pr_debug("clockdomain: %s does not support forcing "
			 "sleep via software\n", clkdm->name);
		return -EINVAL;
	}

	pr_debug("clockdomain: forcing sleep on %s\n", clkdm->name);

	if (cpu_is_omap24xx()) {

		cm_set_mod_reg_bits(OMAP24XX_FORCESTATE,
			    clkdm->pwrdm.ptr->prcm_offs, OMAP2_PM_PWSTCTRL);

	} else if (cpu_is_omap34xx()) {

		u32 v = (OMAP34XX_CLKSTCTRL_FORCE_SLEEP <<
			 __ffs(clkdm->clktrctrl_mask));

		cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, v,
				    clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL);

	} else {
		BUG();
	};

	return 0;
}

/**
 * omap2_clkdm_wakeup - force clockdomain wakeup transition
 * @clkdm: struct clockdomain *
 *
 * Instruct the CM to force a wakeup transition on the specified
 * clockdomain 'clkdm'.  Returns -EINVAL if clkdm is NULL or if the
 * clockdomain does not support software-controlled wakeup; 0 upon
 * success.
 */
int omap2_clkdm_wakeup(struct clockdomain *clkdm)
{
	if (!clkdm)
		return -EINVAL;

	if (!(clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)) {
		pr_debug("clockdomain: %s does not support forcing "
			 "wakeup via software\n", clkdm->name);
		return -EINVAL;
	}

	pr_debug("clockdomain: forcing wakeup on %s\n", clkdm->name);

	if (cpu_is_omap24xx()) {

		cm_clear_mod_reg_bits(OMAP24XX_FORCESTATE,
			      clkdm->pwrdm.ptr->prcm_offs, OMAP2_PM_PWSTCTRL);

	} else if (cpu_is_omap34xx()) {

		u32 v = (OMAP34XX_CLKSTCTRL_FORCE_WAKEUP <<
			 __ffs(clkdm->clktrctrl_mask));

		cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, v,
				    clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL);

	} else {
		BUG();
	};

	return 0;
}

/**
 * omap2_clkdm_allow_idle - enable hwsup idle transitions for clkdm
 * @clkdm: struct clockdomain *
 *
 * Allow the hardware to automatically switch the clockdomain into
 * active or idle states, as needed by downstream clocks.  If the
 * clockdomain has any downstream clocks enabled in the clock
 * framework, wkdep/sleepdep autodependencies are added; this is so
 * device drivers can read and write to the device.  No return value.
 */
void omap2_clkdm_allow_idle(struct clockdomain *clkdm)
{
	if (!clkdm)
		return;

	if (!(clkdm->flags & CLKDM_CAN_ENABLE_AUTO)) {
		pr_debug("clock: automatic idle transitions cannot be enabled "
			 "on clockdomain %s\n", clkdm->name);
		return;
	}

	pr_debug("clockdomain: enabling automatic idle transitions for %s\n",
		 clkdm->name);

	if (atomic_read(&clkdm->usecount) > 0)
		_clkdm_add_autodeps(clkdm);

	_omap2_clkdm_set_hwsup(clkdm, 1);

	pwrdm_clkdm_state_switch(clkdm);
}

/**
 * omap2_clkdm_deny_idle - disable hwsup idle transitions for clkdm
 * @clkdm: struct clockdomain *
 *
 * Prevent the hardware from automatically switching the clockdomain
 * into inactive or idle states.  If the clockdomain has downstream
 * clocks enabled in the clock framework, wkdep/sleepdep
 * autodependencies are removed.  No return value.
 */
void omap2_clkdm_deny_idle(struct clockdomain *clkdm)
{
	if (!clkdm)
		return;

	if (!(clkdm->flags & CLKDM_CAN_DISABLE_AUTO)) {
		pr_debug("clockdomain: automatic idle transitions cannot be "
			 "disabled on %s\n", clkdm->name);
		return;
	}

	pr_debug("clockdomain: disabling automatic idle transitions for %s\n",
		 clkdm->name);

	_omap2_clkdm_set_hwsup(clkdm, 0);

	if (atomic_read(&clkdm->usecount) > 0)
		_clkdm_del_autodeps(clkdm);
}


/* Clockdomain-to-clock framework interface code */

/**
 * omap2_clkdm_clk_enable - add an enabled downstream clock to this clkdm
 * @clkdm: struct clockdomain *
 * @clk: struct clk * of the enabled downstream clock
 *
 * Increment the usecount of this clockdomain 'clkdm' and ensure that
 * it is awake.  Intended to be called by clk_enable() code.  If the
 * clockdomain is in software-supervised idle mode, force the
 * clockdomain to wake.  If the clockdomain is in hardware-supervised
 * idle mode, add clkdm-pwrdm autodependencies, to ensure that devices
 * in the clockdomain can be read from/written to by on-chip processors.
 * Returns -EINVAL if passed null pointers; returns 0 upon success or
 * if the clockdomain is in hwsup idle mode.
 */
int omap2_clkdm_clk_enable(struct clockdomain *clkdm, struct clk *clk)
{
	int v;

	/*
	 * XXX Rewrite this code to maintain a list of enabled
	 * downstream clocks for debugging purposes?
	 */

	if (!clkdm || !clk || !clkdm->clktrctrl_mask)
		return -EINVAL;

	if (atomic_inc_return(&clkdm->usecount) > 1)
		return 0;

	/* Clockdomain now has one enabled downstream clock */

	pr_debug("clockdomain: clkdm %s: clk %s now enabled\n", clkdm->name,
		 clk->name);

	v = omap2_clkdm_clktrctrl_read(clkdm);

	if ((cpu_is_omap34xx() && v == OMAP34XX_CLKSTCTRL_ENABLE_AUTO) ||
	    (cpu_is_omap24xx() && v == OMAP24XX_CLKSTCTRL_ENABLE_AUTO)) {
		/* Disable HW transitions when we are changing deps */
		_omap2_clkdm_set_hwsup(clkdm, 0);
		_clkdm_add_autodeps(clkdm);
		_omap2_clkdm_set_hwsup(clkdm, 1);
	} else {
		omap2_clkdm_wakeup(clkdm);
	}

	pwrdm_wait_transition(clkdm->pwrdm.ptr);
	pwrdm_clkdm_state_switch(clkdm);

	return 0;
}

/**
 * omap2_clkdm_clk_disable - remove an enabled downstream clock from this clkdm
 * @clkdm: struct clockdomain *
 * @clk: struct clk * of the disabled downstream clock
 *
 * Decrement the usecount of this clockdomain 'clkdm'. Intended to be
 * called by clk_disable() code.  If the usecount goes to 0, put the
 * clockdomain to sleep (software-supervised mode) or remove the
 * clkdm-pwrdm autodependencies (hardware-supervised mode).  Returns
 * -EINVAL if passed null pointers; -ERANGE if the clkdm usecount
 * underflows and debugging is enabled; or returns 0 upon success or
 * if the clockdomain is in hwsup idle mode.
 */
int omap2_clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk)
{
	int v;

	/*
	 * XXX Rewrite this code to maintain a list of enabled
	 * downstream clocks for debugging purposes?
	 */

	if (!clkdm || !clk || !clkdm->clktrctrl_mask)
		return -EINVAL;

#ifdef DEBUG
	if (atomic_read(&clkdm->usecount) == 0) {
		WARN_ON(1); /* underflow */
		return -ERANGE;
	}
#endif

	if (atomic_dec_return(&clkdm->usecount) > 0)
		return 0;

	/* All downstream clocks of this clockdomain are now disabled */

	pr_debug("clockdomain: clkdm %s: clk %s now disabled\n", clkdm->name,
		 clk->name);

	v = omap2_clkdm_clktrctrl_read(clkdm);

	if ((cpu_is_omap34xx() && v == OMAP34XX_CLKSTCTRL_ENABLE_AUTO) ||
	    (cpu_is_omap24xx() && v == OMAP24XX_CLKSTCTRL_ENABLE_AUTO)) {
		/* Disable HW transitions when we are changing deps */
		_omap2_clkdm_set_hwsup(clkdm, 0);
		_clkdm_del_autodeps(clkdm);
		_omap2_clkdm_set_hwsup(clkdm, 1);
	} else {
		omap2_clkdm_sleep(clkdm);
	}

	pwrdm_clkdm_state_switch(clkdm);

	return 0;
}