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Paul Walmsleyd459bfe2008-08-19 11:08:43 +03001/*
2 * OMAP2/3 clockdomain framework functions
3 *
4 * Copyright (C) 2008 Texas Instruments, Inc.
5 * Copyright (C) 2008 Nokia Corporation
6 *
7 * Written by Paul Walmsley and Jouni Högander
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 */
13#ifdef CONFIG_OMAP_DEBUG_CLOCKDOMAIN
14# define DEBUG
15#endif
16
17#include <linux/module.h>
18#include <linux/kernel.h>
19#include <linux/device.h>
20#include <linux/list.h>
21#include <linux/errno.h>
22#include <linux/delay.h>
23#include <linux/clk.h>
24#include <linux/limits.h>
25
26#include <linux/io.h>
27
28#include <linux/bitops.h>
29
30#include <mach/clock.h>
31
32#include "prm.h"
33#include "prm-regbits-24xx.h"
34#include "cm.h"
35
36#include <mach/powerdomain.h>
37#include <mach/clockdomain.h>
38
39/* clkdm_list contains all registered struct clockdomains */
40static LIST_HEAD(clkdm_list);
41
42/* clkdm_mutex protects clkdm_list add and del ops */
43static DEFINE_MUTEX(clkdm_mutex);
44
45/* array of powerdomain deps to be added/removed when clkdm in hwsup mode */
46static struct clkdm_pwrdm_autodep *autodeps;
47
48
49/* Private functions */
50
51/*
52 * _autodep_lookup - resolve autodep pwrdm names to pwrdm pointers; store
53 * @autodep: struct clkdm_pwrdm_autodep * to resolve
54 *
55 * Resolve autodep powerdomain names to powerdomain pointers via
56 * pwrdm_lookup() and store the pointers in the autodep structure. An
57 * "autodep" is a powerdomain sleep/wakeup dependency that is
58 * automatically added and removed whenever clocks in the associated
59 * clockdomain are enabled or disabled (respectively) when the
60 * clockdomain is in hardware-supervised mode. Meant to be called
61 * once at clockdomain layer initialization, since these should remain
62 * fixed for a particular architecture. No return value.
63 */
64static void _autodep_lookup(struct clkdm_pwrdm_autodep *autodep)
65{
66 struct powerdomain *pwrdm;
67
68 if (!autodep)
69 return;
70
71 if (!omap_chip_is(autodep->omap_chip))
72 return;
73
74 pwrdm = pwrdm_lookup(autodep->pwrdm_name);
75 if (!pwrdm) {
76 pr_debug("clockdomain: _autodep_lookup: powerdomain %s "
77 "does not exist\n", autodep->pwrdm_name);
78 WARN_ON(1);
79 return;
80 }
81 autodep->pwrdm = pwrdm;
82
83 return;
84}
85
86/*
87 * _clkdm_add_autodeps - add auto sleepdeps/wkdeps to clkdm upon clock enable
88 * @clkdm: struct clockdomain *
89 *
90 * Add the "autodep" sleep & wakeup dependencies to clockdomain 'clkdm'
91 * in hardware-supervised mode. Meant to be called from clock framework
92 * when a clock inside clockdomain 'clkdm' is enabled. No return value.
93 */
94static void _clkdm_add_autodeps(struct clockdomain *clkdm)
95{
96 struct clkdm_pwrdm_autodep *autodep;
97
98 for (autodep = autodeps; autodep->pwrdm_name; autodep++) {
99 if (!autodep->pwrdm)
100 continue;
101
102 pr_debug("clockdomain: adding %s sleepdep/wkdep for "
103 "pwrdm %s\n", autodep->pwrdm_name,
104 clkdm->pwrdm->name);
105
106 pwrdm_add_sleepdep(clkdm->pwrdm, autodep->pwrdm);
107 pwrdm_add_wkdep(clkdm->pwrdm, autodep->pwrdm);
108 }
109}
110
111/*
112 * _clkdm_add_autodeps - remove auto sleepdeps/wkdeps from clkdm
113 * @clkdm: struct clockdomain *
114 *
115 * Remove the "autodep" sleep & wakeup dependencies from clockdomain 'clkdm'
116 * in hardware-supervised mode. Meant to be called from clock framework
117 * when a clock inside clockdomain 'clkdm' is disabled. No return value.
118 */
119static void _clkdm_del_autodeps(struct clockdomain *clkdm)
120{
121 struct clkdm_pwrdm_autodep *autodep;
122
123 for (autodep = autodeps; autodep->pwrdm_name; autodep++) {
124 if (!autodep->pwrdm)
125 continue;
126
127 pr_debug("clockdomain: removing %s sleepdep/wkdep for "
128 "pwrdm %s\n", autodep->pwrdm_name,
129 clkdm->pwrdm->name);
130
131 pwrdm_del_sleepdep(clkdm->pwrdm, autodep->pwrdm);
132 pwrdm_del_wkdep(clkdm->pwrdm, autodep->pwrdm);
133 }
134}
135
136
137static struct clockdomain *_clkdm_lookup(const char *name)
138{
139 struct clockdomain *clkdm, *temp_clkdm;
140
141 if (!name)
142 return NULL;
143
144 clkdm = NULL;
145
146 list_for_each_entry(temp_clkdm, &clkdm_list, node) {
147 if (!strcmp(name, temp_clkdm->name)) {
148 clkdm = temp_clkdm;
149 break;
150 }
151 }
152
153 return clkdm;
154}
155
156
157/* Public functions */
158
159/**
160 * clkdm_init - set up the clockdomain layer
161 * @clkdms: optional pointer to an array of clockdomains to register
162 * @init_autodeps: optional pointer to an array of autodeps to register
163 *
164 * Set up internal state. If a pointer to an array of clockdomains
165 * was supplied, loop through the list of clockdomains, register all
166 * that are available on the current platform. Similarly, if a
167 * pointer to an array of clockdomain-powerdomain autodependencies was
168 * provided, register those. No return value.
169 */
170void clkdm_init(struct clockdomain **clkdms,
171 struct clkdm_pwrdm_autodep *init_autodeps)
172{
173 struct clockdomain **c = NULL;
174 struct clkdm_pwrdm_autodep *autodep = NULL;
175
176 if (clkdms)
177 for (c = clkdms; *c; c++)
178 clkdm_register(*c);
179
180 autodeps = init_autodeps;
181 if (autodeps)
182 for (autodep = autodeps; autodep->pwrdm_name; autodep++)
183 _autodep_lookup(autodep);
184}
185
186/**
187 * clkdm_register - register a clockdomain
188 * @clkdm: struct clockdomain * to register
189 *
190 * Adds a clockdomain to the internal clockdomain list.
191 * Returns -EINVAL if given a null pointer, -EEXIST if a clockdomain is
192 * already registered by the provided name, or 0 upon success.
193 */
194int clkdm_register(struct clockdomain *clkdm)
195{
196 int ret = -EINVAL;
197 struct powerdomain *pwrdm;
198
199 if (!clkdm || !clkdm->name)
200 return -EINVAL;
201
202 if (!omap_chip_is(clkdm->omap_chip))
203 return -EINVAL;
204
205 pwrdm = pwrdm_lookup(clkdm->pwrdm_name);
206 if (!pwrdm) {
207 pr_debug("clockdomain: clkdm_register %s: powerdomain %s "
208 "does not exist\n", clkdm->name, clkdm->pwrdm_name);
209 return -EINVAL;
210 }
211 clkdm->pwrdm = pwrdm;
212
213 mutex_lock(&clkdm_mutex);
214 /* Verify that the clockdomain is not already registered */
215 if (_clkdm_lookup(clkdm->name)) {
216 ret = -EEXIST;
217 goto cr_unlock;
218 };
219
220 list_add(&clkdm->node, &clkdm_list);
221
Paul Walmsley8420bb12008-08-19 11:08:44 +0300222 pwrdm_add_clkdm(pwrdm, clkdm);
223
Paul Walmsleyd459bfe2008-08-19 11:08:43 +0300224 pr_debug("clockdomain: registered %s\n", clkdm->name);
225 ret = 0;
226
227cr_unlock:
228 mutex_unlock(&clkdm_mutex);
229
230 return ret;
231}
232
233/**
234 * clkdm_unregister - unregister a clockdomain
235 * @clkdm: struct clockdomain * to unregister
236 *
237 * Removes a clockdomain from the internal clockdomain list. Returns
238 * -EINVAL if clkdm argument is NULL.
239 */
240int clkdm_unregister(struct clockdomain *clkdm)
241{
242 if (!clkdm)
243 return -EINVAL;
244
Paul Walmsley8420bb12008-08-19 11:08:44 +0300245 pwrdm_del_clkdm(clkdm->pwrdm, clkdm);
246
Paul Walmsleyd459bfe2008-08-19 11:08:43 +0300247 mutex_lock(&clkdm_mutex);
248 list_del(&clkdm->node);
249 mutex_unlock(&clkdm_mutex);
250
251 pr_debug("clockdomain: unregistered %s\n", clkdm->name);
252
253 return 0;
254}
255
256/**
257 * clkdm_lookup - look up a clockdomain by name, return a pointer
258 * @name: name of clockdomain
259 *
260 * Find a registered clockdomain by its name. Returns a pointer to the
261 * struct clockdomain if found, or NULL otherwise.
262 */
263struct clockdomain *clkdm_lookup(const char *name)
264{
265 struct clockdomain *clkdm, *temp_clkdm;
266
267 if (!name)
268 return NULL;
269
270 clkdm = NULL;
271
272 mutex_lock(&clkdm_mutex);
273 list_for_each_entry(temp_clkdm, &clkdm_list, node) {
274 if (!strcmp(name, temp_clkdm->name)) {
275 clkdm = temp_clkdm;
276 break;
277 }
278 }
279 mutex_unlock(&clkdm_mutex);
280
281 return clkdm;
282}
283
284/**
285 * clkdm_for_each - call function on each registered clockdomain
286 * @fn: callback function *
287 *
288 * Call the supplied function for each registered clockdomain.
289 * The callback function can return anything but 0 to bail
290 * out early from the iterator. The callback function is called with
291 * the clkdm_mutex held, so no clockdomain structure manipulation
292 * functions should be called from the callback, although hardware
293 * clockdomain control functions are fine. Returns the last return
294 * value of the callback function, which should be 0 for success or
295 * anything else to indicate failure; or -EINVAL if the function pointer
296 * is null.
297 */
298int clkdm_for_each(int (*fn)(struct clockdomain *clkdm))
299{
300 struct clockdomain *clkdm;
301 int ret = 0;
302
303 if (!fn)
304 return -EINVAL;
305
306 mutex_lock(&clkdm_mutex);
307 list_for_each_entry(clkdm, &clkdm_list, node) {
308 ret = (*fn)(clkdm);
309 if (ret)
310 break;
311 }
312 mutex_unlock(&clkdm_mutex);
313
314 return ret;
315}
316
317
Paul Walmsleye89087c2008-05-20 18:41:35 -0600318/**
319 * clkdm_get_pwrdm - return a ptr to the pwrdm that this clkdm resides in
320 * @clkdm: struct clockdomain *
321 *
322 * Return a pointer to the struct powerdomain that the specified clockdomain
323 * 'clkdm' exists in, or returns NULL if clkdm argument is NULL.
324 */
325struct powerdomain *clkdm_get_pwrdm(struct clockdomain *clkdm)
326{
327 if (!clkdm)
328 return NULL;
329
330 return clkdm->pwrdm;
331}
332
333
Paul Walmsleyd459bfe2008-08-19 11:08:43 +0300334/* Hardware clockdomain control */
335
336/**
337 * omap2_clkdm_clktrctrl_read - read the clkdm's current state transition mode
338 * @clk: struct clk * of a clockdomain
339 *
340 * Return the clockdomain's current state transition mode from the
341 * corresponding domain CM_CLKSTCTRL register. Returns -EINVAL if clk
342 * is NULL or the current mode upon success.
343 */
344static int omap2_clkdm_clktrctrl_read(struct clockdomain *clkdm)
345{
346 u32 v;
347
348 if (!clkdm)
349 return -EINVAL;
350
351 v = cm_read_mod_reg(clkdm->pwrdm->prcm_offs, CM_CLKSTCTRL);
352 v &= clkdm->clktrctrl_mask;
353 v >>= __ffs(clkdm->clktrctrl_mask);
354
355 return v;
356}
357
358/**
359 * omap2_clkdm_sleep - force clockdomain sleep transition
360 * @clkdm: struct clockdomain *
361 *
362 * Instruct the CM to force a sleep transition on the specified
363 * clockdomain 'clkdm'. Returns -EINVAL if clk is NULL or if
364 * clockdomain does not support software-initiated sleep; 0 upon
365 * success.
366 */
367int omap2_clkdm_sleep(struct clockdomain *clkdm)
368{
369 if (!clkdm)
370 return -EINVAL;
371
372 if (!(clkdm->flags & CLKDM_CAN_FORCE_SLEEP)) {
373 pr_debug("clockdomain: %s does not support forcing "
374 "sleep via software\n", clkdm->name);
375 return -EINVAL;
376 }
377
378 pr_debug("clockdomain: forcing sleep on %s\n", clkdm->name);
379
380 if (cpu_is_omap24xx()) {
381
382 cm_set_mod_reg_bits(OMAP24XX_FORCESTATE,
383 clkdm->pwrdm->prcm_offs, PM_PWSTCTRL);
384
385 } else if (cpu_is_omap34xx()) {
386
387 u32 v = (OMAP34XX_CLKSTCTRL_FORCE_SLEEP <<
388 __ffs(clkdm->clktrctrl_mask));
389
390 cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, v,
391 clkdm->pwrdm->prcm_offs, CM_CLKSTCTRL);
392
393 } else {
394 BUG();
395 };
396
397 return 0;
398}
399
400/**
401 * omap2_clkdm_wakeup - force clockdomain wakeup transition
402 * @clkdm: struct clockdomain *
403 *
404 * Instruct the CM to force a wakeup transition on the specified
405 * clockdomain 'clkdm'. Returns -EINVAL if clkdm is NULL or if the
406 * clockdomain does not support software-controlled wakeup; 0 upon
407 * success.
408 */
409int omap2_clkdm_wakeup(struct clockdomain *clkdm)
410{
411 if (!clkdm)
412 return -EINVAL;
413
414 if (!(clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)) {
415 pr_debug("clockdomain: %s does not support forcing "
416 "wakeup via software\n", clkdm->name);
417 return -EINVAL;
418 }
419
420 pr_debug("clockdomain: forcing wakeup on %s\n", clkdm->name);
421
422 if (cpu_is_omap24xx()) {
423
424 cm_clear_mod_reg_bits(OMAP24XX_FORCESTATE,
425 clkdm->pwrdm->prcm_offs, PM_PWSTCTRL);
426
427 } else if (cpu_is_omap34xx()) {
428
429 u32 v = (OMAP34XX_CLKSTCTRL_FORCE_WAKEUP <<
430 __ffs(clkdm->clktrctrl_mask));
431
432 cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, v,
433 clkdm->pwrdm->prcm_offs, CM_CLKSTCTRL);
434
435 } else {
436 BUG();
437 };
438
439 return 0;
440}
441
442/**
443 * omap2_clkdm_allow_idle - enable hwsup idle transitions for clkdm
444 * @clkdm: struct clockdomain *
445 *
446 * Allow the hardware to automatically switch the clockdomain into
447 * active or idle states, as needed by downstream clocks. If the
448 * clockdomain has any downstream clocks enabled in the clock
449 * framework, wkdep/sleepdep autodependencies are added; this is so
450 * device drivers can read and write to the device. No return value.
451 */
452void omap2_clkdm_allow_idle(struct clockdomain *clkdm)
453{
454 u32 v;
455
456 if (!clkdm)
457 return;
458
459 if (!(clkdm->flags & CLKDM_CAN_ENABLE_AUTO)) {
460 pr_debug("clock: automatic idle transitions cannot be enabled "
461 "on clockdomain %s\n", clkdm->name);
462 return;
463 }
464
465 pr_debug("clockdomain: enabling automatic idle transitions for %s\n",
466 clkdm->name);
467
468 if (atomic_read(&clkdm->usecount) > 0)
469 _clkdm_add_autodeps(clkdm);
470
471 if (cpu_is_omap24xx())
472 v = OMAP24XX_CLKSTCTRL_ENABLE_AUTO;
473 else if (cpu_is_omap34xx())
474 v = OMAP34XX_CLKSTCTRL_ENABLE_AUTO;
475 else
476 BUG();
477
478
479 cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask,
480 v << __ffs(clkdm->clktrctrl_mask),
481 clkdm->pwrdm->prcm_offs,
482 CM_CLKSTCTRL);
483}
484
485/**
486 * omap2_clkdm_deny_idle - disable hwsup idle transitions for clkdm
487 * @clkdm: struct clockdomain *
488 *
489 * Prevent the hardware from automatically switching the clockdomain
490 * into inactive or idle states. If the clockdomain has downstream
491 * clocks enabled in the clock framework, wkdep/sleepdep
492 * autodependencies are removed. No return value.
493 */
494void omap2_clkdm_deny_idle(struct clockdomain *clkdm)
495{
496 u32 v;
497
498 if (!clkdm)
499 return;
500
501 if (!(clkdm->flags & CLKDM_CAN_DISABLE_AUTO)) {
502 pr_debug("clockdomain: automatic idle transitions cannot be "
503 "disabled on %s\n", clkdm->name);
504 return;
505 }
506
507 pr_debug("clockdomain: disabling automatic idle transitions for %s\n",
508 clkdm->name);
509
510 if (cpu_is_omap24xx())
511 v = OMAP24XX_CLKSTCTRL_DISABLE_AUTO;
512 else if (cpu_is_omap34xx())
513 v = OMAP34XX_CLKSTCTRL_DISABLE_AUTO;
514 else
515 BUG();
516
517 cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask,
518 v << __ffs(clkdm->clktrctrl_mask),
519 clkdm->pwrdm->prcm_offs, CM_CLKSTCTRL);
520
521 if (atomic_read(&clkdm->usecount) > 0)
522 _clkdm_del_autodeps(clkdm);
523}
524
525
526/* Clockdomain-to-clock framework interface code */
527
528/**
529 * omap2_clkdm_clk_enable - add an enabled downstream clock to this clkdm
530 * @clkdm: struct clockdomain *
531 * @clk: struct clk * of the enabled downstream clock
532 *
533 * Increment the usecount of this clockdomain 'clkdm' and ensure that
534 * it is awake. Intended to be called by clk_enable() code. If the
535 * clockdomain is in software-supervised idle mode, force the
536 * clockdomain to wake. If the clockdomain is in hardware-supervised
537 * idle mode, add clkdm-pwrdm autodependencies, to ensure that devices
538 * in the clockdomain can be read from/written to by on-chip processors.
539 * Returns -EINVAL if passed null pointers; returns 0 upon success or
540 * if the clockdomain is in hwsup idle mode.
541 */
542int omap2_clkdm_clk_enable(struct clockdomain *clkdm, struct clk *clk)
543{
544 int v;
545
546 /*
547 * XXX Rewrite this code to maintain a list of enabled
548 * downstream clocks for debugging purposes?
549 */
550
551 if (!clkdm || !clk)
552 return -EINVAL;
553
554 if (atomic_inc_return(&clkdm->usecount) > 1)
555 return 0;
556
557 /* Clockdomain now has one enabled downstream clock */
558
559 pr_debug("clockdomain: clkdm %s: clk %s now enabled\n", clkdm->name,
560 clk->name);
561
562 v = omap2_clkdm_clktrctrl_read(clkdm);
563
564 if ((cpu_is_omap34xx() && v == OMAP34XX_CLKSTCTRL_ENABLE_AUTO) ||
565 (cpu_is_omap24xx() && v == OMAP24XX_CLKSTCTRL_ENABLE_AUTO))
566 _clkdm_add_autodeps(clkdm);
567 else
568 omap2_clkdm_wakeup(clkdm);
569
570 return 0;
571}
572
573/**
574 * omap2_clkdm_clk_disable - remove an enabled downstream clock from this clkdm
575 * @clkdm: struct clockdomain *
576 * @clk: struct clk * of the disabled downstream clock
577 *
578 * Decrement the usecount of this clockdomain 'clkdm'. Intended to be
579 * called by clk_disable() code. If the usecount goes to 0, put the
580 * clockdomain to sleep (software-supervised mode) or remove the
581 * clkdm-pwrdm autodependencies (hardware-supervised mode). Returns
582 * -EINVAL if passed null pointers; -ERANGE if the clkdm usecount
583 * underflows and debugging is enabled; or returns 0 upon success or
584 * if the clockdomain is in hwsup idle mode.
585 */
586int omap2_clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk)
587{
588 int v;
589
590 /*
591 * XXX Rewrite this code to maintain a list of enabled
592 * downstream clocks for debugging purposes?
593 */
594
595 if (!clkdm || !clk)
596 return -EINVAL;
597
598#ifdef DEBUG
599 if (atomic_read(&clkdm->usecount) == 0) {
600 WARN_ON(1); /* underflow */
601 return -ERANGE;
602 }
603#endif
604
605 if (atomic_dec_return(&clkdm->usecount) > 0)
606 return 0;
607
608 /* All downstream clocks of this clockdomain are now disabled */
609
610 pr_debug("clockdomain: clkdm %s: clk %s now disabled\n", clkdm->name,
611 clk->name);
612
613 v = omap2_clkdm_clktrctrl_read(clkdm);
614
615 if ((cpu_is_omap34xx() && v == OMAP34XX_CLKSTCTRL_ENABLE_AUTO) ||
616 (cpu_is_omap24xx() && v == OMAP24XX_CLKSTCTRL_ENABLE_AUTO))
617 _clkdm_del_autodeps(clkdm);
618 else
619 omap2_clkdm_sleep(clkdm);
620
621 return 0;
622}
623