1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * OMAP2/3/4 clockdomain framework functions
4  *
5  * Copyright (C) 2008-2011 Texas Instruments, Inc.
6  * Copyright (C) 2008-2011 Nokia Corporation
7  *
8  * Written by Paul Walmsley and Jouni Högander
9  * Added OMAP4 specific support by Abhijit Pagare <abhijitpagare@ti.com>
10  */
11 #undef DEBUG
12 
13 #include <linux/kernel.h>
14 #include <linux/device.h>
15 #include <linux/list.h>
16 #include <linux/errno.h>
17 #include <linux/string.h>
18 #include <linux/delay.h>
19 #include <linux/clk.h>
20 #include <linux/limits.h>
21 #include <linux/err.h>
22 #include <linux/clk-provider.h>
23 #include <linux/cpu_pm.h>
24 
25 #include <linux/io.h>
26 
27 #include <linux/bitops.h>
28 
29 #include "soc.h"
30 #include "clock.h"
31 #include "clockdomain.h"
32 #include "pm.h"
33 
34 /* clkdm_list contains all registered struct clockdomains */
35 static LIST_HEAD(clkdm_list);
36 
37 /* array of clockdomain deps to be added/removed when clkdm in hwsup mode */
38 static struct clkdm_autodep *autodeps;
39 
40 static struct clkdm_ops *arch_clkdm;
41 void clkdm_save_context(void);
42 void clkdm_restore_context(void);
43 
44 /* Private functions */
45 
46 static struct clockdomain *_clkdm_lookup(const char *name)
47 {
48 	struct clockdomain *clkdm, *temp_clkdm;
49 
50 	if (!name)
51 		return NULL;
52 
53 	clkdm = NULL;
54 
55 	list_for_each_entry(temp_clkdm, &clkdm_list, node) {
56 		if (!strcmp(name, temp_clkdm->name)) {
57 			clkdm = temp_clkdm;
58 			break;
59 		}
60 	}
61 
62 	return clkdm;
63 }
64 
65 /**
66  * _clkdm_register - register a clockdomain
67  * @clkdm: struct clockdomain * to register
68  *
69  * Adds a clockdomain to the internal clockdomain list.
70  * Returns -EINVAL if given a null pointer, -EEXIST if a clockdomain is
71  * already registered by the provided name, or 0 upon success.
72  */
73 static int _clkdm_register(struct clockdomain *clkdm)
74 {
75 	struct powerdomain *pwrdm;
76 
77 	if (!clkdm || !clkdm->name)
78 		return -EINVAL;
79 
80 	pwrdm = pwrdm_lookup(clkdm->pwrdm.name);
81 	if (!pwrdm) {
82 		pr_err("clockdomain: %s: powerdomain %s does not exist\n",
83 			clkdm->name, clkdm->pwrdm.name);
84 		return -EINVAL;
85 	}
86 	clkdm->pwrdm.ptr = pwrdm;
87 
88 	/* Verify that the clockdomain is not already registered */
89 	if (_clkdm_lookup(clkdm->name))
90 		return -EEXIST;
91 
92 	list_add(&clkdm->node, &clkdm_list);
93 
94 	pwrdm_add_clkdm(pwrdm, clkdm);
95 
96 	pr_debug("clockdomain: registered %s\n", clkdm->name);
97 
98 	return 0;
99 }
100 
101 /* _clkdm_deps_lookup - look up the specified clockdomain in a clkdm list */
102 static struct clkdm_dep *_clkdm_deps_lookup(struct clockdomain *clkdm,
103 					    struct clkdm_dep *deps)
104 {
105 	struct clkdm_dep *cd;
106 
107 	if (!clkdm || !deps)
108 		return ERR_PTR(-EINVAL);
109 
110 	for (cd = deps; cd->clkdm_name; cd++) {
111 		if (!cd->clkdm && cd->clkdm_name)
112 			cd->clkdm = _clkdm_lookup(cd->clkdm_name);
113 
114 		if (cd->clkdm == clkdm)
115 			break;
116 	}
117 
118 	if (!cd->clkdm_name)
119 		return ERR_PTR(-ENOENT);
120 
121 	return cd;
122 }
123 
124 /**
125  * _autodep_lookup - resolve autodep clkdm names to clkdm pointers; store
126  * @autodep: struct clkdm_autodep * to resolve
127  *
128  * Resolve autodep clockdomain names to clockdomain pointers via
129  * clkdm_lookup() and store the pointers in the autodep structure.  An
130  * "autodep" is a clockdomain sleep/wakeup dependency that is
131  * automatically added and removed whenever clocks in the associated
132  * clockdomain are enabled or disabled (respectively) when the
133  * clockdomain is in hardware-supervised mode.	Meant to be called
134  * once at clockdomain layer initialization, since these should remain
135  * fixed for a particular architecture.  No return value.
136  *
137  * XXX autodeps are deprecated and should be removed at the earliest
138  * opportunity
139  */
140 static void _autodep_lookup(struct clkdm_autodep *autodep)
141 {
142 	struct clockdomain *clkdm;
143 
144 	if (!autodep)
145 		return;
146 
147 	clkdm = clkdm_lookup(autodep->clkdm.name);
148 	if (!clkdm) {
149 		pr_err("clockdomain: autodeps: clockdomain %s does not exist\n",
150 			 autodep->clkdm.name);
151 		clkdm = ERR_PTR(-ENOENT);
152 	}
153 	autodep->clkdm.ptr = clkdm;
154 }
155 
156 /**
157  * _resolve_clkdm_deps() - resolve clkdm_names in @clkdm_deps to clkdms
158  * @clkdm: clockdomain that we are resolving dependencies for
159  * @clkdm_deps: ptr to array of struct clkdm_deps to resolve
160  *
161  * Iterates through @clkdm_deps, looking up the struct clockdomain named by
162  * clkdm_name and storing the clockdomain pointer in the struct clkdm_dep.
163  * No return value.
164  */
165 static void _resolve_clkdm_deps(struct clockdomain *clkdm,
166 				struct clkdm_dep *clkdm_deps)
167 {
168 	struct clkdm_dep *cd;
169 
170 	for (cd = clkdm_deps; cd && cd->clkdm_name; cd++) {
171 		if (cd->clkdm)
172 			continue;
173 		cd->clkdm = _clkdm_lookup(cd->clkdm_name);
174 
175 		WARN(!cd->clkdm, "clockdomain: %s: could not find clkdm %s while resolving dependencies - should never happen",
176 		     clkdm->name, cd->clkdm_name);
177 	}
178 }
179 
180 /**
181  * _clkdm_add_wkdep - add a wakeup dependency from clkdm2 to clkdm1 (lockless)
182  * @clkdm1: wake this struct clockdomain * up (dependent)
183  * @clkdm2: when this struct clockdomain * wakes up (source)
184  *
185  * When the clockdomain represented by @clkdm2 wakes up, wake up
186  * @clkdm1. Implemented in hardware on the OMAP, this feature is
187  * designed to reduce wakeup latency of the dependent clockdomain @clkdm1.
188  * Returns -EINVAL if presented with invalid clockdomain pointers,
189  * -ENOENT if @clkdm2 cannot wake up clkdm1 in hardware, or 0 upon
190  * success.
191  */
192 static int _clkdm_add_wkdep(struct clockdomain *clkdm1,
193 			    struct clockdomain *clkdm2)
194 {
195 	struct clkdm_dep *cd;
196 	int ret = 0;
197 
198 	if (!clkdm1 || !clkdm2)
199 		return -EINVAL;
200 
201 	cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
202 	if (IS_ERR(cd))
203 		ret = PTR_ERR(cd);
204 
205 	if (!arch_clkdm || !arch_clkdm->clkdm_add_wkdep)
206 		ret = -EINVAL;
207 
208 	if (ret) {
209 		pr_debug("clockdomain: hardware cannot set/clear wake up of %s when %s wakes up\n",
210 			 clkdm1->name, clkdm2->name);
211 		return ret;
212 	}
213 
214 	cd->wkdep_usecount++;
215 	if (cd->wkdep_usecount == 1) {
216 		pr_debug("clockdomain: hardware will wake up %s when %s wakes up\n",
217 			 clkdm1->name, clkdm2->name);
218 
219 		ret = arch_clkdm->clkdm_add_wkdep(clkdm1, clkdm2);
220 	}
221 
222 	return ret;
223 }
224 
225 /**
226  * _clkdm_del_wkdep - remove a wakeup dep from clkdm2 to clkdm1 (lockless)
227  * @clkdm1: wake this struct clockdomain * up (dependent)
228  * @clkdm2: when this struct clockdomain * wakes up (source)
229  *
230  * Remove a wakeup dependency causing @clkdm1 to wake up when @clkdm2
231  * wakes up.  Returns -EINVAL if presented with invalid clockdomain
232  * pointers, -ENOENT if @clkdm2 cannot wake up clkdm1 in hardware, or
233  * 0 upon success.
234  */
235 static int _clkdm_del_wkdep(struct clockdomain *clkdm1,
236 			    struct clockdomain *clkdm2)
237 {
238 	struct clkdm_dep *cd;
239 	int ret = 0;
240 
241 	if (!clkdm1 || !clkdm2)
242 		return -EINVAL;
243 
244 	cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
245 	if (IS_ERR(cd))
246 		ret = PTR_ERR(cd);
247 
248 	if (!arch_clkdm || !arch_clkdm->clkdm_del_wkdep)
249 		ret = -EINVAL;
250 
251 	if (ret) {
252 		pr_debug("clockdomain: hardware cannot set/clear wake up of %s when %s wakes up\n",
253 			 clkdm1->name, clkdm2->name);
254 		return ret;
255 	}
256 
257 	cd->wkdep_usecount--;
258 	if (cd->wkdep_usecount == 0) {
259 		pr_debug("clockdomain: hardware will no longer wake up %s after %s wakes up\n",
260 			 clkdm1->name, clkdm2->name);
261 
262 		ret = arch_clkdm->clkdm_del_wkdep(clkdm1, clkdm2);
263 	}
264 
265 	return ret;
266 }
267 
268 /**
269  * _clkdm_add_sleepdep - add a sleep dependency from clkdm2 to clkdm1 (lockless)
270  * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
271  * @clkdm2: when this struct clockdomain * is active (source)
272  *
273  * Prevent @clkdm1 from automatically going inactive (and then to
274  * retention or off) if @clkdm2 is active.  Returns -EINVAL if
275  * presented with invalid clockdomain pointers or called on a machine
276  * that does not support software-configurable hardware sleep
277  * dependencies, -ENOENT if the specified dependency cannot be set in
278  * hardware, or 0 upon success.
279  */
280 static int _clkdm_add_sleepdep(struct clockdomain *clkdm1,
281 			       struct clockdomain *clkdm2)
282 {
283 	struct clkdm_dep *cd;
284 	int ret = 0;
285 
286 	if (!clkdm1 || !clkdm2)
287 		return -EINVAL;
288 
289 	cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
290 	if (IS_ERR(cd))
291 		ret = PTR_ERR(cd);
292 
293 	if (!arch_clkdm || !arch_clkdm->clkdm_add_sleepdep)
294 		ret = -EINVAL;
295 
296 	if (ret) {
297 		pr_debug("clockdomain: hardware cannot set/clear sleep dependency affecting %s from %s\n",
298 			 clkdm1->name, clkdm2->name);
299 		return ret;
300 	}
301 
302 	cd->sleepdep_usecount++;
303 	if (cd->sleepdep_usecount == 1) {
304 		pr_debug("clockdomain: will prevent %s from sleeping if %s is active\n",
305 			 clkdm1->name, clkdm2->name);
306 
307 		ret = arch_clkdm->clkdm_add_sleepdep(clkdm1, clkdm2);
308 	}
309 
310 	return ret;
311 }
312 
313 /**
314  * _clkdm_del_sleepdep - remove a sleep dep from clkdm2 to clkdm1 (lockless)
315  * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
316  * @clkdm2: when this struct clockdomain * is active (source)
317  *
318  * Allow @clkdm1 to automatically go inactive (and then to retention or
319  * off), independent of the activity state of @clkdm2.  Returns -EINVAL
320  * if presented with invalid clockdomain pointers or called on a machine
321  * that does not support software-configurable hardware sleep dependencies,
322  * -ENOENT if the specified dependency cannot be cleared in hardware, or
323  * 0 upon success.
324  */
325 static int _clkdm_del_sleepdep(struct clockdomain *clkdm1,
326 			       struct clockdomain *clkdm2)
327 {
328 	struct clkdm_dep *cd;
329 	int ret = 0;
330 
331 	if (!clkdm1 || !clkdm2)
332 		return -EINVAL;
333 
334 	cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
335 	if (IS_ERR(cd))
336 		ret = PTR_ERR(cd);
337 
338 	if (!arch_clkdm || !arch_clkdm->clkdm_del_sleepdep)
339 		ret = -EINVAL;
340 
341 	if (ret) {
342 		pr_debug("clockdomain: hardware cannot set/clear sleep dependency affecting %s from %s\n",
343 			 clkdm1->name, clkdm2->name);
344 		return ret;
345 	}
346 
347 	cd->sleepdep_usecount--;
348 	if (cd->sleepdep_usecount == 0) {
349 		pr_debug("clockdomain: will no longer prevent %s from sleeping if %s is active\n",
350 			 clkdm1->name, clkdm2->name);
351 
352 		ret = arch_clkdm->clkdm_del_sleepdep(clkdm1, clkdm2);
353 	}
354 
355 	return ret;
356 }
357 
358 /* Public functions */
359 
360 /**
361  * clkdm_register_platform_funcs - register clockdomain implementation fns
362  * @co: func pointers for arch specific implementations
363  *
364  * Register the list of function pointers used to implement the
365  * clockdomain functions on different OMAP SoCs.  Should be called
366  * before any other clkdm_register*() function.  Returns -EINVAL if
367  * @co is null, -EEXIST if platform functions have already been
368  * registered, or 0 upon success.
369  */
370 int clkdm_register_platform_funcs(struct clkdm_ops *co)
371 {
372 	if (!co)
373 		return -EINVAL;
374 
375 	if (arch_clkdm)
376 		return -EEXIST;
377 
378 	arch_clkdm = co;
379 
380 	return 0;
381 };
382 
383 /**
384  * clkdm_register_clkdms - register SoC clockdomains
385  * @cs: pointer to an array of struct clockdomain to register
386  *
387  * Register the clockdomains available on a particular OMAP SoC.  Must
388  * be called after clkdm_register_platform_funcs().  May be called
389  * multiple times.  Returns -EACCES if called before
390  * clkdm_register_platform_funcs(); -EINVAL if the argument @cs is
391  * null; or 0 upon success.
392  */
393 int clkdm_register_clkdms(struct clockdomain **cs)
394 {
395 	struct clockdomain **c = NULL;
396 
397 	if (!arch_clkdm)
398 		return -EACCES;
399 
400 	if (!cs)
401 		return -EINVAL;
402 
403 	for (c = cs; *c; c++)
404 		_clkdm_register(*c);
405 
406 	return 0;
407 }
408 
409 /**
410  * clkdm_register_autodeps - register autodeps (if required)
411  * @ia: pointer to a static array of struct clkdm_autodep to register
412  *
413  * Register clockdomain "automatic dependencies."  These are
414  * clockdomain wakeup and sleep dependencies that are automatically
415  * added whenever the first clock inside a clockdomain is enabled, and
416  * removed whenever the last clock inside a clockdomain is disabled.
417  * These are currently only used on OMAP3 devices, and are deprecated,
418  * since they waste energy.  However, until the OMAP2/3 IP block
419  * enable/disable sequence can be converted to match the OMAP4
420  * sequence, they are needed.
421  *
422  * Must be called only after all of the SoC clockdomains are
423  * registered, since the function will resolve autodep clockdomain
424  * names into clockdomain pointers.
425  *
426  * The struct clkdm_autodep @ia array must be static, as this function
427  * does not copy the array elements.
428  *
429  * Returns -EACCES if called before any clockdomains have been
430  * registered, -EINVAL if called with a null @ia argument, -EEXIST if
431  * autodeps have already been registered, or 0 upon success.
432  */
433 int clkdm_register_autodeps(struct clkdm_autodep *ia)
434 {
435 	struct clkdm_autodep *a = NULL;
436 
437 	if (list_empty(&clkdm_list))
438 		return -EACCES;
439 
440 	if (!ia)
441 		return -EINVAL;
442 
443 	if (autodeps)
444 		return -EEXIST;
445 
446 	autodeps = ia;
447 	for (a = autodeps; a->clkdm.ptr; a++)
448 		_autodep_lookup(a);
449 
450 	return 0;
451 }
452 
453 static int cpu_notifier(struct notifier_block *nb, unsigned long cmd, void *v)
454 {
455 	switch (cmd) {
456 	case CPU_CLUSTER_PM_ENTER:
457 		if (enable_off_mode)
458 			clkdm_save_context();
459 		break;
460 	case CPU_CLUSTER_PM_EXIT:
461 		if (enable_off_mode)
462 			clkdm_restore_context();
463 		break;
464 	}
465 
466 	return NOTIFY_OK;
467 }
468 
469 /**
470  * clkdm_complete_init - set up the clockdomain layer
471  *
472  * Put all clockdomains into software-supervised mode; PM code should
473  * later enable hardware-supervised mode as appropriate.  Must be
474  * called after clkdm_register_clkdms().  Returns -EACCES if called
475  * before clkdm_register_clkdms(), or 0 upon success.
476  */
477 int clkdm_complete_init(void)
478 {
479 	struct clockdomain *clkdm;
480 	static struct notifier_block nb;
481 
482 	if (list_empty(&clkdm_list))
483 		return -EACCES;
484 
485 	list_for_each_entry(clkdm, &clkdm_list, node) {
486 		clkdm_deny_idle(clkdm);
487 
488 		_resolve_clkdm_deps(clkdm, clkdm->wkdep_srcs);
489 		clkdm_clear_all_wkdeps(clkdm);
490 
491 		_resolve_clkdm_deps(clkdm, clkdm->sleepdep_srcs);
492 		clkdm_clear_all_sleepdeps(clkdm);
493 	}
494 
495 	/* Only AM43XX can lose clkdm context during rtc-ddr suspend */
496 	if (soc_is_am43xx()) {
497 		nb.notifier_call = cpu_notifier;
498 		cpu_pm_register_notifier(&nb);
499 	}
500 
501 	return 0;
502 }
503 
504 /**
505  * clkdm_lookup - look up a clockdomain by name, return a pointer
506  * @name: name of clockdomain
507  *
508  * Find a registered clockdomain by its name @name.  Returns a pointer
509  * to the struct clockdomain if found, or NULL otherwise.
510  */
511 struct clockdomain *clkdm_lookup(const char *name)
512 {
513 	struct clockdomain *clkdm, *temp_clkdm;
514 
515 	if (!name)
516 		return NULL;
517 
518 	clkdm = NULL;
519 
520 	list_for_each_entry(temp_clkdm, &clkdm_list, node) {
521 		if (!strcmp(name, temp_clkdm->name)) {
522 			clkdm = temp_clkdm;
523 			break;
524 		}
525 	}
526 
527 	return clkdm;
528 }
529 
530 /**
531  * clkdm_for_each - call function on each registered clockdomain
532  * @fn: callback function *
533  *
534  * Call the supplied function @fn for each registered clockdomain.
535  * The callback function @fn can return anything but 0 to bail
536  * out early from the iterator.  The callback function is called with
537  * the clkdm_mutex held, so no clockdomain structure manipulation
538  * functions should be called from the callback, although hardware
539  * clockdomain control functions are fine.  Returns the last return
540  * value of the callback function, which should be 0 for success or
541  * anything else to indicate failure; or -EINVAL if the function pointer
542  * is null.
543  */
544 int clkdm_for_each(int (*fn)(struct clockdomain *clkdm, void *user),
545 			void *user)
546 {
547 	struct clockdomain *clkdm;
548 	int ret = 0;
549 
550 	if (!fn)
551 		return -EINVAL;
552 
553 	list_for_each_entry(clkdm, &clkdm_list, node) {
554 		ret = (*fn)(clkdm, user);
555 		if (ret)
556 			break;
557 	}
558 
559 	return ret;
560 }
561 
562 
563 /**
564  * clkdm_get_pwrdm - return a ptr to the pwrdm that this clkdm resides in
565  * @clkdm: struct clockdomain *
566  *
567  * Return a pointer to the struct powerdomain that the specified clockdomain
568  * @clkdm exists in, or returns NULL if @clkdm is NULL.
569  */
570 struct powerdomain *clkdm_get_pwrdm(struct clockdomain *clkdm)
571 {
572 	if (!clkdm)
573 		return NULL;
574 
575 	return clkdm->pwrdm.ptr;
576 }
577 
578 
579 /* Hardware clockdomain control */
580 
581 /**
582  * clkdm_add_wkdep - add a wakeup dependency from clkdm2 to clkdm1
583  * @clkdm1: wake this struct clockdomain * up (dependent)
584  * @clkdm2: when this struct clockdomain * wakes up (source)
585  *
586  * When the clockdomain represented by @clkdm2 wakes up, wake up
587  * @clkdm1. Implemented in hardware on the OMAP, this feature is
588  * designed to reduce wakeup latency of the dependent clockdomain @clkdm1.
589  * Returns -EINVAL if presented with invalid clockdomain pointers,
590  * -ENOENT if @clkdm2 cannot wake up clkdm1 in hardware, or 0 upon
591  * success.
592  */
593 int clkdm_add_wkdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
594 {
595 	struct clkdm_dep *cd;
596 	int ret;
597 
598 	if (!clkdm1 || !clkdm2)
599 		return -EINVAL;
600 
601 	cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
602 	if (IS_ERR(cd))
603 		return PTR_ERR(cd);
604 
605 	pwrdm_lock(cd->clkdm->pwrdm.ptr);
606 	ret = _clkdm_add_wkdep(clkdm1, clkdm2);
607 	pwrdm_unlock(cd->clkdm->pwrdm.ptr);
608 
609 	return ret;
610 }
611 
612 /**
613  * clkdm_del_wkdep - remove a wakeup dependency from clkdm2 to clkdm1
614  * @clkdm1: wake this struct clockdomain * up (dependent)
615  * @clkdm2: when this struct clockdomain * wakes up (source)
616  *
617  * Remove a wakeup dependency causing @clkdm1 to wake up when @clkdm2
618  * wakes up.  Returns -EINVAL if presented with invalid clockdomain
619  * pointers, -ENOENT if @clkdm2 cannot wake up clkdm1 in hardware, or
620  * 0 upon success.
621  */
622 int clkdm_del_wkdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
623 {
624 	struct clkdm_dep *cd;
625 	int ret;
626 
627 	if (!clkdm1 || !clkdm2)
628 		return -EINVAL;
629 
630 	cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
631 	if (IS_ERR(cd))
632 		return PTR_ERR(cd);
633 
634 	pwrdm_lock(cd->clkdm->pwrdm.ptr);
635 	ret = _clkdm_del_wkdep(clkdm1, clkdm2);
636 	pwrdm_unlock(cd->clkdm->pwrdm.ptr);
637 
638 	return ret;
639 }
640 
641 /**
642  * clkdm_read_wkdep - read wakeup dependency state from clkdm2 to clkdm1
643  * @clkdm1: wake this struct clockdomain * up (dependent)
644  * @clkdm2: when this struct clockdomain * wakes up (source)
645  *
646  * Return 1 if a hardware wakeup dependency exists wherein @clkdm1 will be
647  * awoken when @clkdm2 wakes up; 0 if dependency is not set; -EINVAL
648  * if either clockdomain pointer is invalid; or -ENOENT if the hardware
649  * is incapable.
650  *
651  * REVISIT: Currently this function only represents software-controllable
652  * wakeup dependencies.  Wakeup dependencies fixed in hardware are not
653  * yet handled here.
654  */
655 int clkdm_read_wkdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
656 {
657 	struct clkdm_dep *cd;
658 	int ret = 0;
659 
660 	if (!clkdm1 || !clkdm2)
661 		return -EINVAL;
662 
663 	cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
664 	if (IS_ERR(cd))
665 		ret = PTR_ERR(cd);
666 
667 	if (!arch_clkdm || !arch_clkdm->clkdm_read_wkdep)
668 		ret = -EINVAL;
669 
670 	if (ret) {
671 		pr_debug("clockdomain: hardware cannot set/clear wake up of %s when %s wakes up\n",
672 			 clkdm1->name, clkdm2->name);
673 		return ret;
674 	}
675 
676 	/* XXX It's faster to return the wkdep_usecount */
677 	return arch_clkdm->clkdm_read_wkdep(clkdm1, clkdm2);
678 }
679 
680 /**
681  * clkdm_clear_all_wkdeps - remove all wakeup dependencies from target clkdm
682  * @clkdm: struct clockdomain * to remove all wakeup dependencies from
683  *
684  * Remove all inter-clockdomain wakeup dependencies that could cause
685  * @clkdm to wake.  Intended to be used during boot to initialize the
686  * PRCM to a known state, after all clockdomains are put into swsup idle
687  * and woken up.  Returns -EINVAL if @clkdm pointer is invalid, or
688  * 0 upon success.
689  */
690 int clkdm_clear_all_wkdeps(struct clockdomain *clkdm)
691 {
692 	if (!clkdm)
693 		return -EINVAL;
694 
695 	if (!arch_clkdm || !arch_clkdm->clkdm_clear_all_wkdeps)
696 		return -EINVAL;
697 
698 	return arch_clkdm->clkdm_clear_all_wkdeps(clkdm);
699 }
700 
701 /**
702  * clkdm_add_sleepdep - add a sleep dependency from clkdm2 to clkdm1
703  * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
704  * @clkdm2: when this struct clockdomain * is active (source)
705  *
706  * Prevent @clkdm1 from automatically going inactive (and then to
707  * retention or off) if @clkdm2 is active.  Returns -EINVAL if
708  * presented with invalid clockdomain pointers or called on a machine
709  * that does not support software-configurable hardware sleep
710  * dependencies, -ENOENT if the specified dependency cannot be set in
711  * hardware, or 0 upon success.
712  */
713 int clkdm_add_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
714 {
715 	struct clkdm_dep *cd;
716 	int ret;
717 
718 	if (!clkdm1 || !clkdm2)
719 		return -EINVAL;
720 
721 	cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
722 	if (IS_ERR(cd))
723 		return PTR_ERR(cd);
724 
725 	pwrdm_lock(cd->clkdm->pwrdm.ptr);
726 	ret = _clkdm_add_sleepdep(clkdm1, clkdm2);
727 	pwrdm_unlock(cd->clkdm->pwrdm.ptr);
728 
729 	return ret;
730 }
731 
732 /**
733  * clkdm_del_sleepdep - remove a sleep dependency from clkdm2 to clkdm1
734  * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
735  * @clkdm2: when this struct clockdomain * is active (source)
736  *
737  * Allow @clkdm1 to automatically go inactive (and then to retention or
738  * off), independent of the activity state of @clkdm2.  Returns -EINVAL
739  * if presented with invalid clockdomain pointers or called on a machine
740  * that does not support software-configurable hardware sleep dependencies,
741  * -ENOENT if the specified dependency cannot be cleared in hardware, or
742  * 0 upon success.
743  */
744 int clkdm_del_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
745 {
746 	struct clkdm_dep *cd;
747 	int ret;
748 
749 	if (!clkdm1 || !clkdm2)
750 		return -EINVAL;
751 
752 	cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
753 	if (IS_ERR(cd))
754 		return PTR_ERR(cd);
755 
756 	pwrdm_lock(cd->clkdm->pwrdm.ptr);
757 	ret = _clkdm_del_sleepdep(clkdm1, clkdm2);
758 	pwrdm_unlock(cd->clkdm->pwrdm.ptr);
759 
760 	return ret;
761 }
762 
763 /**
764  * clkdm_read_sleepdep - read sleep dependency state from clkdm2 to clkdm1
765  * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
766  * @clkdm2: when this struct clockdomain * is active (source)
767  *
768  * Return 1 if a hardware sleep dependency exists wherein @clkdm1 will
769  * not be allowed to automatically go inactive if @clkdm2 is active;
770  * 0 if @clkdm1's automatic power state inactivity transition is independent
771  * of @clkdm2's; -EINVAL if either clockdomain pointer is invalid or called
772  * on a machine that does not support software-configurable hardware sleep
773  * dependencies; or -ENOENT if the hardware is incapable.
774  *
775  * REVISIT: Currently this function only represents software-controllable
776  * sleep dependencies.	Sleep dependencies fixed in hardware are not
777  * yet handled here.
778  */
779 int clkdm_read_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
780 {
781 	struct clkdm_dep *cd;
782 	int ret = 0;
783 
784 	if (!clkdm1 || !clkdm2)
785 		return -EINVAL;
786 
787 	cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
788 	if (IS_ERR(cd))
789 		ret = PTR_ERR(cd);
790 
791 	if (!arch_clkdm || !arch_clkdm->clkdm_read_sleepdep)
792 		ret = -EINVAL;
793 
794 	if (ret) {
795 		pr_debug("clockdomain: hardware cannot set/clear sleep dependency affecting %s from %s\n",
796 			 clkdm1->name, clkdm2->name);
797 		return ret;
798 	}
799 
800 	/* XXX It's faster to return the sleepdep_usecount */
801 	return arch_clkdm->clkdm_read_sleepdep(clkdm1, clkdm2);
802 }
803 
804 /**
805  * clkdm_clear_all_sleepdeps - remove all sleep dependencies from target clkdm
806  * @clkdm: struct clockdomain * to remove all sleep dependencies from
807  *
808  * Remove all inter-clockdomain sleep dependencies that could prevent
809  * @clkdm from idling.  Intended to be used during boot to initialize the
810  * PRCM to a known state, after all clockdomains are put into swsup idle
811  * and woken up.  Returns -EINVAL if @clkdm pointer is invalid, or
812  * 0 upon success.
813  */
814 int clkdm_clear_all_sleepdeps(struct clockdomain *clkdm)
815 {
816 	if (!clkdm)
817 		return -EINVAL;
818 
819 	if (!arch_clkdm || !arch_clkdm->clkdm_clear_all_sleepdeps)
820 		return -EINVAL;
821 
822 	return arch_clkdm->clkdm_clear_all_sleepdeps(clkdm);
823 }
824 
825 /**
826  * clkdm_sleep_nolock - force clockdomain sleep transition (lockless)
827  * @clkdm: struct clockdomain *
828  *
829  * Instruct the CM to force a sleep transition on the specified
830  * clockdomain @clkdm.  Only for use by the powerdomain code.  Returns
831  * -EINVAL if @clkdm is NULL or if clockdomain does not support
832  * software-initiated sleep; 0 upon success.
833  */
834 int clkdm_sleep_nolock(struct clockdomain *clkdm)
835 {
836 	int ret;
837 
838 	if (!clkdm)
839 		return -EINVAL;
840 
841 	if (!(clkdm->flags & CLKDM_CAN_FORCE_SLEEP)) {
842 		pr_debug("clockdomain: %s does not support forcing sleep via software\n",
843 			 clkdm->name);
844 		return -EINVAL;
845 	}
846 
847 	if (!arch_clkdm || !arch_clkdm->clkdm_sleep)
848 		return -EINVAL;
849 
850 	pr_debug("clockdomain: forcing sleep on %s\n", clkdm->name);
851 
852 	clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
853 	ret = arch_clkdm->clkdm_sleep(clkdm);
854 	ret |= pwrdm_state_switch_nolock(clkdm->pwrdm.ptr);
855 
856 	return ret;
857 }
858 
859 /**
860  * clkdm_sleep - force clockdomain sleep transition
861  * @clkdm: struct clockdomain *
862  *
863  * Instruct the CM to force a sleep transition on the specified
864  * clockdomain @clkdm.  Returns -EINVAL if @clkdm is NULL or if
865  * clockdomain does not support software-initiated sleep; 0 upon
866  * success.
867  */
868 int clkdm_sleep(struct clockdomain *clkdm)
869 {
870 	int ret;
871 
872 	pwrdm_lock(clkdm->pwrdm.ptr);
873 	ret = clkdm_sleep_nolock(clkdm);
874 	pwrdm_unlock(clkdm->pwrdm.ptr);
875 
876 	return ret;
877 }
878 
879 /**
880  * clkdm_wakeup_nolock - force clockdomain wakeup transition (lockless)
881  * @clkdm: struct clockdomain *
882  *
883  * Instruct the CM to force a wakeup transition on the specified
884  * clockdomain @clkdm.  Only for use by the powerdomain code.  Returns
885  * -EINVAL if @clkdm is NULL or if the clockdomain does not support
886  * software-controlled wakeup; 0 upon success.
887  */
888 int clkdm_wakeup_nolock(struct clockdomain *clkdm)
889 {
890 	int ret;
891 
892 	if (!clkdm)
893 		return -EINVAL;
894 
895 	if (!(clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)) {
896 		pr_debug("clockdomain: %s does not support forcing wakeup via software\n",
897 			 clkdm->name);
898 		return -EINVAL;
899 	}
900 
901 	if (!arch_clkdm || !arch_clkdm->clkdm_wakeup)
902 		return -EINVAL;
903 
904 	pr_debug("clockdomain: forcing wakeup on %s\n", clkdm->name);
905 
906 	clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
907 	ret = arch_clkdm->clkdm_wakeup(clkdm);
908 	ret |= pwrdm_state_switch_nolock(clkdm->pwrdm.ptr);
909 
910 	return ret;
911 }
912 
913 /**
914  * clkdm_wakeup - force clockdomain wakeup transition
915  * @clkdm: struct clockdomain *
916  *
917  * Instruct the CM to force a wakeup transition on the specified
918  * clockdomain @clkdm.  Returns -EINVAL if @clkdm is NULL or if the
919  * clockdomain does not support software-controlled wakeup; 0 upon
920  * success.
921  */
922 int clkdm_wakeup(struct clockdomain *clkdm)
923 {
924 	int ret;
925 
926 	pwrdm_lock(clkdm->pwrdm.ptr);
927 	ret = clkdm_wakeup_nolock(clkdm);
928 	pwrdm_unlock(clkdm->pwrdm.ptr);
929 
930 	return ret;
931 }
932 
933 /**
934  * clkdm_allow_idle_nolock - enable hwsup idle transitions for clkdm
935  * @clkdm: struct clockdomain *
936  *
937  * Allow the hardware to automatically switch the clockdomain @clkdm
938  * into active or idle states, as needed by downstream clocks.  If the
939  * clockdomain has any downstream clocks enabled in the clock
940  * framework, wkdep/sleepdep autodependencies are added; this is so
941  * device drivers can read and write to the device.  Only for use by
942  * the powerdomain code.  No return value.
943  */
944 void clkdm_allow_idle_nolock(struct clockdomain *clkdm)
945 {
946 	if (!clkdm)
947 		return;
948 
949 	if (!WARN_ON(!clkdm->forcewake_count))
950 		clkdm->forcewake_count--;
951 
952 	if (clkdm->forcewake_count)
953 		return;
954 
955 	if (!clkdm->usecount && (clkdm->flags & CLKDM_CAN_FORCE_SLEEP))
956 		clkdm_sleep_nolock(clkdm);
957 
958 	if (!(clkdm->flags & CLKDM_CAN_ENABLE_AUTO))
959 		return;
960 
961 	if (clkdm->flags & CLKDM_MISSING_IDLE_REPORTING)
962 		return;
963 
964 	if (!arch_clkdm || !arch_clkdm->clkdm_allow_idle)
965 		return;
966 
967 	pr_debug("clockdomain: enabling automatic idle transitions for %s\n",
968 		 clkdm->name);
969 
970 	clkdm->_flags |= _CLKDM_FLAG_HWSUP_ENABLED;
971 	arch_clkdm->clkdm_allow_idle(clkdm);
972 	pwrdm_state_switch_nolock(clkdm->pwrdm.ptr);
973 }
974 
975 /**
976  * clkdm_allow_idle - enable hwsup idle transitions for clkdm
977  * @clkdm: struct clockdomain *
978  *
979  * Allow the hardware to automatically switch the clockdomain @clkdm into
980  * active or idle states, as needed by downstream clocks.  If the
981  * clockdomain has any downstream clocks enabled in the clock
982  * framework, wkdep/sleepdep autodependencies are added; this is so
983  * device drivers can read and write to the device.  No return value.
984  */
985 void clkdm_allow_idle(struct clockdomain *clkdm)
986 {
987 	pwrdm_lock(clkdm->pwrdm.ptr);
988 	clkdm_allow_idle_nolock(clkdm);
989 	pwrdm_unlock(clkdm->pwrdm.ptr);
990 }
991 
992 /**
993  * clkdm_deny_idle - disable hwsup idle transitions for clkdm
994  * @clkdm: struct clockdomain *
995  *
996  * Prevent the hardware from automatically switching the clockdomain
997  * @clkdm into inactive or idle states.  If the clockdomain has
998  * downstream clocks enabled in the clock framework, wkdep/sleepdep
999  * autodependencies are removed.  Only for use by the powerdomain
1000  * code.  No return value.
1001  */
1002 void clkdm_deny_idle_nolock(struct clockdomain *clkdm)
1003 {
1004 	if (!clkdm)
1005 		return;
1006 
1007 	if (clkdm->forcewake_count++)
1008 		return;
1009 
1010 	if (clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)
1011 		clkdm_wakeup_nolock(clkdm);
1012 
1013 	if (!(clkdm->flags & CLKDM_CAN_DISABLE_AUTO))
1014 		return;
1015 
1016 	if (clkdm->flags & CLKDM_MISSING_IDLE_REPORTING)
1017 		return;
1018 
1019 	if (!arch_clkdm || !arch_clkdm->clkdm_deny_idle)
1020 		return;
1021 
1022 	pr_debug("clockdomain: disabling automatic idle transitions for %s\n",
1023 		 clkdm->name);
1024 
1025 	clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
1026 	arch_clkdm->clkdm_deny_idle(clkdm);
1027 	pwrdm_state_switch_nolock(clkdm->pwrdm.ptr);
1028 }
1029 
1030 /**
1031  * clkdm_deny_idle - disable hwsup idle transitions for clkdm
1032  * @clkdm: struct clockdomain *
1033  *
1034  * Prevent the hardware from automatically switching the clockdomain
1035  * @clkdm into inactive or idle states.  If the clockdomain has
1036  * downstream clocks enabled in the clock framework, wkdep/sleepdep
1037  * autodependencies are removed.  No return value.
1038  */
1039 void clkdm_deny_idle(struct clockdomain *clkdm)
1040 {
1041 	pwrdm_lock(clkdm->pwrdm.ptr);
1042 	clkdm_deny_idle_nolock(clkdm);
1043 	pwrdm_unlock(clkdm->pwrdm.ptr);
1044 }
1045 
1046 /**
1047  * clkdm_in_hwsup - is clockdomain @clkdm have hardware-supervised idle enabled?
1048  * @clkdm: struct clockdomain *
1049  *
1050  * Returns true if clockdomain @clkdm currently has
1051  * hardware-supervised idle enabled, or false if it does not or if
1052  * @clkdm is NULL.  It is only valid to call this function after
1053  * clkdm_init() has been called.  This function does not actually read
1054  * bits from the hardware; it instead tests an in-memory flag that is
1055  * changed whenever the clockdomain code changes the auto-idle mode.
1056  */
1057 bool clkdm_in_hwsup(struct clockdomain *clkdm)
1058 {
1059 	bool ret;
1060 
1061 	if (!clkdm)
1062 		return false;
1063 
1064 	ret = (clkdm->_flags & _CLKDM_FLAG_HWSUP_ENABLED) ? true : false;
1065 
1066 	return ret;
1067 }
1068 
1069 /**
1070  * clkdm_missing_idle_reporting - can @clkdm enter autoidle even if in use?
1071  * @clkdm: struct clockdomain *
1072  *
1073  * Returns true if clockdomain @clkdm has the
1074  * CLKDM_MISSING_IDLE_REPORTING flag set, or false if not or @clkdm is
1075  * null.  More information is available in the documentation for the
1076  * CLKDM_MISSING_IDLE_REPORTING macro.
1077  */
1078 bool clkdm_missing_idle_reporting(struct clockdomain *clkdm)
1079 {
1080 	if (!clkdm)
1081 		return false;
1082 
1083 	return (clkdm->flags & CLKDM_MISSING_IDLE_REPORTING) ? true : false;
1084 }
1085 
1086 /* Public autodep handling functions (deprecated) */
1087 
1088 /**
1089  * clkdm_add_autodeps - add auto sleepdeps/wkdeps to clkdm upon clock enable
1090  * @clkdm: struct clockdomain *
1091  *
1092  * Add the "autodep" sleep & wakeup dependencies to clockdomain 'clkdm'
1093  * in hardware-supervised mode.  Meant to be called from clock framework
1094  * when a clock inside clockdomain 'clkdm' is enabled.	No return value.
1095  *
1096  * XXX autodeps are deprecated and should be removed at the earliest
1097  * opportunity
1098  */
1099 void clkdm_add_autodeps(struct clockdomain *clkdm)
1100 {
1101 	struct clkdm_autodep *autodep;
1102 
1103 	if (!autodeps || clkdm->flags & CLKDM_NO_AUTODEPS)
1104 		return;
1105 
1106 	for (autodep = autodeps; autodep->clkdm.ptr; autodep++) {
1107 		if (IS_ERR(autodep->clkdm.ptr))
1108 			continue;
1109 
1110 		pr_debug("clockdomain: %s: adding %s sleepdep/wkdep\n",
1111 			 clkdm->name, autodep->clkdm.ptr->name);
1112 
1113 		_clkdm_add_sleepdep(clkdm, autodep->clkdm.ptr);
1114 		_clkdm_add_wkdep(clkdm, autodep->clkdm.ptr);
1115 	}
1116 }
1117 
1118 /**
1119  * clkdm_del_autodeps - remove auto sleepdeps/wkdeps from clkdm
1120  * @clkdm: struct clockdomain *
1121  *
1122  * Remove the "autodep" sleep & wakeup dependencies from clockdomain 'clkdm'
1123  * in hardware-supervised mode.  Meant to be called from clock framework
1124  * when a clock inside clockdomain 'clkdm' is disabled.  No return value.
1125  *
1126  * XXX autodeps are deprecated and should be removed at the earliest
1127  * opportunity
1128  */
1129 void clkdm_del_autodeps(struct clockdomain *clkdm)
1130 {
1131 	struct clkdm_autodep *autodep;
1132 
1133 	if (!autodeps || clkdm->flags & CLKDM_NO_AUTODEPS)
1134 		return;
1135 
1136 	for (autodep = autodeps; autodep->clkdm.ptr; autodep++) {
1137 		if (IS_ERR(autodep->clkdm.ptr))
1138 			continue;
1139 
1140 		pr_debug("clockdomain: %s: removing %s sleepdep/wkdep\n",
1141 			 clkdm->name, autodep->clkdm.ptr->name);
1142 
1143 		_clkdm_del_sleepdep(clkdm, autodep->clkdm.ptr);
1144 		_clkdm_del_wkdep(clkdm, autodep->clkdm.ptr);
1145 	}
1146 }
1147 
1148 /* Clockdomain-to-clock/hwmod framework interface code */
1149 
1150 /**
1151  * clkdm_clk_enable - add an enabled downstream clock to this clkdm
1152  * @clkdm: struct clockdomain *
1153  * @clk: struct clk * of the enabled downstream clock
1154  *
1155  * Increment the usecount of the clockdomain @clkdm and ensure that it
1156  * is awake before @clk is enabled.  Intended to be called by
1157  * clk_enable() code.  If the clockdomain is in software-supervised
1158  * idle mode, force the clockdomain to wake.  If the clockdomain is in
1159  * hardware-supervised idle mode, add clkdm-pwrdm autodependencies, to
1160  * ensure that devices in the clockdomain can be read from/written to
1161  * by on-chip processors.  Returns -EINVAL if passed null pointers;
1162  * returns 0 upon success or if the clockdomain is in hwsup idle mode.
1163  */
1164 int clkdm_clk_enable(struct clockdomain *clkdm, struct clk *unused)
1165 {
1166 	if (!clkdm || !arch_clkdm || !arch_clkdm->clkdm_clk_enable)
1167 		return -EINVAL;
1168 
1169 	pwrdm_lock(clkdm->pwrdm.ptr);
1170 
1171 	/*
1172 	 * For arch's with no autodeps, clkcm_clk_enable
1173 	 * should be called for every clock instance or hwmod that is
1174 	 * enabled, so the clkdm can be force woken up.
1175 	 */
1176 	clkdm->usecount++;
1177 	if (clkdm->usecount > 1 && autodeps) {
1178 		pwrdm_unlock(clkdm->pwrdm.ptr);
1179 		return 0;
1180 	}
1181 
1182 	arch_clkdm->clkdm_clk_enable(clkdm);
1183 	pwrdm_state_switch_nolock(clkdm->pwrdm.ptr);
1184 	pwrdm_unlock(clkdm->pwrdm.ptr);
1185 
1186 	pr_debug("clockdomain: %s: enabled\n", clkdm->name);
1187 
1188 	return 0;
1189 }
1190 
1191 /**
1192  * clkdm_clk_disable - remove an enabled downstream clock from this clkdm
1193  * @clkdm: struct clockdomain *
1194  * @clk: struct clk * of the disabled downstream clock
1195  *
1196  * Decrement the usecount of this clockdomain @clkdm when @clk is
1197  * disabled.  Intended to be called by clk_disable() code.  If the
1198  * clockdomain usecount goes to 0, put the clockdomain to sleep
1199  * (software-supervised mode) or remove the clkdm autodependencies
1200  * (hardware-supervised mode).  Returns -EINVAL if passed null
1201  * pointers; -ERANGE if the @clkdm usecount underflows; or returns 0
1202  * upon success or if the clockdomain is in hwsup idle mode.
1203  */
1204 int clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk)
1205 {
1206 	if (!clkdm || !arch_clkdm || !arch_clkdm->clkdm_clk_disable)
1207 		return -EINVAL;
1208 
1209 	pwrdm_lock(clkdm->pwrdm.ptr);
1210 
1211 	/* corner case: disabling unused clocks */
1212 	if (clk && (__clk_get_enable_count(clk) == 0) && clkdm->usecount == 0)
1213 		goto ccd_exit;
1214 
1215 	if (clkdm->usecount == 0) {
1216 		pwrdm_unlock(clkdm->pwrdm.ptr);
1217 		WARN_ON(1); /* underflow */
1218 		return -ERANGE;
1219 	}
1220 
1221 	clkdm->usecount--;
1222 	if (clkdm->usecount > 0) {
1223 		pwrdm_unlock(clkdm->pwrdm.ptr);
1224 		return 0;
1225 	}
1226 
1227 	arch_clkdm->clkdm_clk_disable(clkdm);
1228 	pwrdm_state_switch_nolock(clkdm->pwrdm.ptr);
1229 
1230 	pr_debug("clockdomain: %s: disabled\n", clkdm->name);
1231 
1232 ccd_exit:
1233 	pwrdm_unlock(clkdm->pwrdm.ptr);
1234 
1235 	return 0;
1236 }
1237 
1238 /**
1239  * clkdm_hwmod_enable - add an enabled downstream hwmod to this clkdm
1240  * @clkdm: struct clockdomain *
1241  * @oh: struct omap_hwmod * of the enabled downstream hwmod
1242  *
1243  * Increment the usecount of the clockdomain @clkdm and ensure that it
1244  * is awake before @oh is enabled. Intended to be called by
1245  * module_enable() code.
1246  * If the clockdomain is in software-supervised idle mode, force the
1247  * clockdomain to wake.  If the clockdomain is in hardware-supervised idle
1248  * mode, add clkdm-pwrdm autodependencies, to ensure that devices in the
1249  * clockdomain can be read from/written to by on-chip processors.
1250  * Returns -EINVAL if passed null pointers;
1251  * returns 0 upon success or if the clockdomain is in hwsup idle mode.
1252  */
1253 int clkdm_hwmod_enable(struct clockdomain *clkdm, struct omap_hwmod *oh)
1254 {
1255 	/* The clkdm attribute does not exist yet prior OMAP4 */
1256 	if (cpu_is_omap24xx() || cpu_is_omap34xx())
1257 		return 0;
1258 
1259 	/*
1260 	 * XXX Rewrite this code to maintain a list of enabled
1261 	 * downstream hwmods for debugging purposes?
1262 	 */
1263 
1264 	if (!oh)
1265 		return -EINVAL;
1266 
1267 	return clkdm_clk_enable(clkdm, NULL);
1268 }
1269 
1270 /**
1271  * clkdm_hwmod_disable - remove an enabled downstream hwmod from this clkdm
1272  * @clkdm: struct clockdomain *
1273  * @oh: struct omap_hwmod * of the disabled downstream hwmod
1274  *
1275  * Decrement the usecount of this clockdomain @clkdm when @oh is
1276  * disabled. Intended to be called by module_disable() code.
1277  * If the clockdomain usecount goes to 0, put the clockdomain to sleep
1278  * (software-supervised mode) or remove the clkdm autodependencies
1279  * (hardware-supervised mode).
1280  * Returns -EINVAL if passed null pointers; -ERANGE if the @clkdm usecount
1281  * underflows; or returns 0 upon success or if the clockdomain is in hwsup
1282  * idle mode.
1283  */
1284 int clkdm_hwmod_disable(struct clockdomain *clkdm, struct omap_hwmod *oh)
1285 {
1286 	/* The clkdm attribute does not exist yet prior OMAP4 */
1287 	if (cpu_is_omap24xx() || cpu_is_omap34xx())
1288 		return 0;
1289 
1290 	if (!oh)
1291 		return -EINVAL;
1292 
1293 	return clkdm_clk_disable(clkdm, NULL);
1294 }
1295 
1296 /**
1297  * _clkdm_save_context - save the context for the control of this clkdm
1298  *
1299  * Due to a suspend or hibernation operation, the state of the registers
1300  * controlling this clkdm will be lost, save their context.
1301  */
1302 static int _clkdm_save_context(struct clockdomain *clkdm, void *unused)
1303 {
1304 	if (!arch_clkdm || !arch_clkdm->clkdm_save_context)
1305 		return -EINVAL;
1306 
1307 	return arch_clkdm->clkdm_save_context(clkdm);
1308 }
1309 
1310 /**
1311  * _clkdm_restore_context - restore context for control of this clkdm
1312  *
1313  * Restore the register values for this clockdomain.
1314  */
1315 static int _clkdm_restore_context(struct clockdomain *clkdm, void *unused)
1316 {
1317 	if (!arch_clkdm || !arch_clkdm->clkdm_restore_context)
1318 		return -EINVAL;
1319 
1320 	return arch_clkdm->clkdm_restore_context(clkdm);
1321 }
1322 
1323 /**
1324  * clkdm_save_context - Saves the context for each registered clkdm
1325  *
1326  * Save the context for each registered clockdomain.
1327  */
1328 void clkdm_save_context(void)
1329 {
1330 	clkdm_for_each(_clkdm_save_context, NULL);
1331 }
1332 
1333 /**
1334  * clkdm_restore_context - Restores the context for each registered clkdm
1335  *
1336  * Restore the context for each registered clockdomain.
1337  */
1338 void clkdm_restore_context(void)
1339 {
1340 	clkdm_for_each(_clkdm_restore_context, NULL);
1341 }
1342