common.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * drivers/base/power/common.c - Common device power management code.
  4 *
  5 * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
  6 */
  7#include <linux/kernel.h>
  8#include <linux/device.h>
  9#include <linux/export.h>
 10#include <linux/slab.h>
 11#include <linux/pm_clock.h>
 12#include <linux/acpi.h>
 13#include <linux/pm_domain.h>
 14#include <linux/pm_opp.h>
 15
 16#include "power.h"
 17
 18/**
 19 * dev_pm_get_subsys_data - Create or refcount power.subsys_data for device.
 20 * @dev: Device to handle.
 21 *
 22 * If power.subsys_data is NULL, point it to a new object, otherwise increment
 23 * its reference counter.  Return 0 if new object has been created or refcount
 24 * increased, otherwise negative error code.
 25 */
 26int dev_pm_get_subsys_data(struct device *dev)
 27{
 28	struct pm_subsys_data *psd;
 29
 30	psd = kzalloc(sizeof(*psd), GFP_KERNEL);
 31	if (!psd)
 32		return -ENOMEM;
 33
 34	spin_lock_irq(&dev->power.lock);
 35
 36	if (dev->power.subsys_data) {
 37		dev->power.subsys_data->refcount++;
 38	} else {
 39		spin_lock_init(&psd->lock);
 40		psd->refcount = 1;
 41		dev->power.subsys_data = psd;
 42		pm_clk_init(dev);
 43		psd = NULL;
 44	}
 45
 46	spin_unlock_irq(&dev->power.lock);
 47
 48	/* kfree() verifies that its argument is nonzero. */
 49	kfree(psd);
 50
 51	return 0;
 52}
 53EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data);
 54
 55/**
 56 * dev_pm_put_subsys_data - Drop reference to power.subsys_data.
 57 * @dev: Device to handle.
 58 *
 59 * If the reference counter of power.subsys_data is zero after dropping the
 60 * reference, power.subsys_data is removed.
 61 */
 62void dev_pm_put_subsys_data(struct device *dev)
 63{
 64	struct pm_subsys_data *psd;
 65
 66	spin_lock_irq(&dev->power.lock);
 67
 68	psd = dev_to_psd(dev);
 69	if (!psd)
 70		goto out;
 71
 72	if (--psd->refcount == 0)
 73		dev->power.subsys_data = NULL;
 74	else
 75		psd = NULL;
 76
 77 out:
 78	spin_unlock_irq(&dev->power.lock);
 79	kfree(psd);
 80}
 81EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);
 82
 83/**
 84 * dev_pm_domain_attach - Attach a device to its PM domain.
 85 * @dev: Device to attach.
 86 * @flags: indicate whether we should power on/off the device on attach/detach
 87 *
 88 * The @dev may only be attached to a single PM domain. By iterating through
 89 * the available alternatives we try to find a valid PM domain for the device.
 90 * As attachment succeeds, the ->detach() callback in the struct dev_pm_domain
 91 * should be assigned by the corresponding attach function.
 92 *
 93 * This function should typically be invoked from subsystem level code during
 94 * the probe phase. Especially for those that holds devices which requires
 95 * power management through PM domains.
 96 *
 97 * Callers must ensure proper synchronization of this function with power
 98 * management callbacks.
 99 *
100 * Returns 0 on successfully attached PM domain, or when it is found that the
101 * device doesn't need a PM domain, else a negative error code.
102 */
103int dev_pm_domain_attach(struct device *dev, u32 flags)
104{
105	int ret;
106
107	if (dev->pm_domain)
108		return 0;
109
110	ret = acpi_dev_pm_attach(dev, !!(flags & PD_FLAG_ATTACH_POWER_ON));
111	if (!ret)
112		ret = genpd_dev_pm_attach(dev);
113
114	if (dev->pm_domain)
115		dev->power.detach_power_off = !!(flags & PD_FLAG_DETACH_POWER_OFF);
116
117	return ret < 0 ? ret : 0;
118}
119EXPORT_SYMBOL_GPL(dev_pm_domain_attach);
120
121/**
122 * dev_pm_domain_attach_by_id - Associate a device with one of its PM domains.
123 * @dev: The device used to lookup the PM domain.
124 * @index: The index of the PM domain.
125 *
126 * As @dev may only be attached to a single PM domain, the backend PM domain
127 * provider creates a virtual device to attach instead. If attachment succeeds,
128 * the ->detach() callback in the struct dev_pm_domain are assigned by the
129 * corresponding backend attach function, as to deal with detaching of the
130 * created virtual device.
131 *
132 * This function should typically be invoked by a driver during the probe phase,
133 * in case its device requires power management through multiple PM domains. The
134 * driver may benefit from using the received device, to configure device-links
135 * towards its original device. Depending on the use-case and if needed, the
136 * links may be dynamically changed by the driver, which allows it to control
137 * the power to the PM domains independently from each other.
138 *
139 * Callers must ensure proper synchronization of this function with power
140 * management callbacks.
141 *
142 * Returns the virtual created device when successfully attached to its PM
143 * domain, NULL in case @dev don't need a PM domain, else an ERR_PTR().
144 * Note that, to detach the returned virtual device, the driver shall call
145 * dev_pm_domain_detach() on it, typically during the remove phase.
146 */
147struct device *dev_pm_domain_attach_by_id(struct device *dev,
148					  unsigned int index)
149{
150	if (dev->pm_domain)
151		return ERR_PTR(-EEXIST);
152
153	return genpd_dev_pm_attach_by_id(dev, index);
154}
155EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_id);
156
157/**
158 * dev_pm_domain_attach_by_name - Associate a device with one of its PM domains.
159 * @dev: The device used to lookup the PM domain.
160 * @name: The name of the PM domain.
161 *
162 * For a detailed function description, see dev_pm_domain_attach_by_id().
163 */
164struct device *dev_pm_domain_attach_by_name(struct device *dev,
165					    const char *name)
166{
167	if (dev->pm_domain)
168		return ERR_PTR(-EEXIST);
169
170	return genpd_dev_pm_attach_by_name(dev, name);
171}
172EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_name);
173
174/**
175 * dev_pm_domain_attach_list - Associate a device with its PM domains.
176 * @dev: The device used to lookup the PM domains for.
177 * @data: The data used for attaching to the PM domains.
178 * @list: An out-parameter with an allocated list of attached PM domains.
179 *
180 * This function helps to attach a device to its multiple PM domains. The
181 * caller, which is typically a driver's probe function, may provide a list of
182 * names for the PM domains that we should try to attach the device to, but it
183 * may also provide an empty list, in case the attach should be done for all of
184 * the available PM domains.
185 *
186 * Callers must ensure proper synchronization of this function with power
187 * management callbacks.
188 *
189 * Returns the number of attached PM domains or a negative error code in case of
190 * a failure. Note that, to detach the list of PM domains, the driver shall call
191 * dev_pm_domain_detach_list(), typically during the remove phase.
192 */
193int dev_pm_domain_attach_list(struct device *dev,
194			      const struct dev_pm_domain_attach_data *data,
195			      struct dev_pm_domain_list **list)
196{
197	struct device_node *np = dev->of_node;
198	struct dev_pm_domain_list *pds;
199	struct device *pd_dev = NULL;
200	int ret, i, num_pds = 0;
201	bool by_id = true;
202	size_t size;
203	u32 pd_flags = data ? data->pd_flags : 0;
204	u32 link_flags = pd_flags & PD_FLAG_NO_DEV_LINK ? 0 :
205			DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME;
206
207	if (dev->pm_domain)
208		return -EEXIST;
209
210	/* For now this is limited to OF based platforms. */
211	if (!np)
212		return 0;
213
214	if (data && data->pd_names) {
215		num_pds = data->num_pd_names;
216		by_id = false;
217	} else {
218		num_pds = of_count_phandle_with_args(np, "power-domains",
219						     "#power-domain-cells");
220	}
221
222	if (num_pds <= 0)
223		return 0;
224
225	pds = kzalloc(sizeof(*pds), GFP_KERNEL);
226	if (!pds)
227		return -ENOMEM;
228
229	size = sizeof(*pds->pd_devs) + sizeof(*pds->pd_links) +
230	       sizeof(*pds->opp_tokens);
231	pds->pd_devs = kcalloc(num_pds, size, GFP_KERNEL);
232	if (!pds->pd_devs) {
233		ret = -ENOMEM;
234		goto free_pds;
235	}
236	pds->pd_links = (void *)(pds->pd_devs + num_pds);
237	pds->opp_tokens = (void *)(pds->pd_links + num_pds);
238
239	if (link_flags && pd_flags & PD_FLAG_DEV_LINK_ON)
240		link_flags |= DL_FLAG_RPM_ACTIVE;
241
242	for (i = 0; i < num_pds; i++) {
243		if (by_id)
244			pd_dev = dev_pm_domain_attach_by_id(dev, i);
245		else
246			pd_dev = dev_pm_domain_attach_by_name(dev,
247							data->pd_names[i]);
248		if (IS_ERR_OR_NULL(pd_dev)) {
249			ret = pd_dev ? PTR_ERR(pd_dev) : -ENODEV;
250			goto err_attach;
251		}
252
253		if (pd_flags & PD_FLAG_REQUIRED_OPP) {
254			struct dev_pm_opp_config config = {
255				.required_dev = pd_dev,
256				.required_dev_index = i,
257			};
258
259			ret = dev_pm_opp_set_config(dev, &config);
260			if (ret < 0)
261				goto err_link;
262
263			pds->opp_tokens[i] = ret;
264		}
265
266		if (link_flags) {
267			struct device_link *link;
268
269			link = device_link_add(dev, pd_dev, link_flags);
270			if (!link) {
271				ret = -ENODEV;
272				goto err_link;
273			}
274
275			pds->pd_links[i] = link;
276		}
277
278		pds->pd_devs[i] = pd_dev;
279	}
280
281	pds->num_pds = num_pds;
282	*list = pds;
283	return num_pds;
284
285err_link:
286	dev_pm_opp_clear_config(pds->opp_tokens[i]);
287	dev_pm_domain_detach(pd_dev, true);
288err_attach:
289	while (--i >= 0) {
290		dev_pm_opp_clear_config(pds->opp_tokens[i]);
291		if (pds->pd_links[i])
292			device_link_del(pds->pd_links[i]);
293		dev_pm_domain_detach(pds->pd_devs[i], true);
294	}
295	kfree(pds->pd_devs);
296free_pds:
297	kfree(pds);
298	return ret;
299}
300EXPORT_SYMBOL_GPL(dev_pm_domain_attach_list);
301
302/**
303 * devm_pm_domain_detach_list - devres-enabled version of dev_pm_domain_detach_list.
304 * @_list: The list of PM domains to detach.
305 *
306 * This function reverse the actions from devm_pm_domain_attach_list().
307 * it will be invoked during the remove phase from drivers implicitly if driver
308 * uses devm_pm_domain_attach_list() to attach the PM domains.
309 */
310static void devm_pm_domain_detach_list(void *_list)
311{
312	struct dev_pm_domain_list *list = _list;
313
314	dev_pm_domain_detach_list(list);
315}
316
317/**
318 * devm_pm_domain_attach_list - devres-enabled version of dev_pm_domain_attach_list
319 * @dev: The device used to lookup the PM domains for.
320 * @data: The data used for attaching to the PM domains.
321 * @list: An out-parameter with an allocated list of attached PM domains.
322 *
323 * NOTE: this will also handle calling devm_pm_domain_detach_list() for
324 * you during remove phase.
325 *
326 * Returns the number of attached PM domains or a negative error code in case of
327 * a failure.
328 */
329int devm_pm_domain_attach_list(struct device *dev,
330			       const struct dev_pm_domain_attach_data *data,
331			       struct dev_pm_domain_list **list)
332{
333	int ret, num_pds;
334
335	num_pds = dev_pm_domain_attach_list(dev, data, list);
336	if (num_pds <= 0)
337		return num_pds;
338
339	ret = devm_add_action_or_reset(dev, devm_pm_domain_detach_list, *list);
340	if (ret)
341		return ret;
342
343	return num_pds;
344}
345EXPORT_SYMBOL_GPL(devm_pm_domain_attach_list);
346
347/**
348 * dev_pm_domain_detach - Detach a device from its PM domain.
349 * @dev: Device to detach.
350 * @power_off: Used to indicate whether we should power off the device.
351 *
352 * This functions will reverse the actions from dev_pm_domain_attach(),
353 * dev_pm_domain_attach_by_id() and dev_pm_domain_attach_by_name(), thus it
354 * detaches @dev from its PM domain.  Typically it should be invoked during the
355 * remove phase, either from subsystem level code or from drivers.
356 *
357 * Callers must ensure proper synchronization of this function with power
358 * management callbacks.
359 */
360void dev_pm_domain_detach(struct device *dev, bool power_off)
361{
362	if (dev->pm_domain && dev->pm_domain->detach)
363		dev->pm_domain->detach(dev, power_off);
364}
365EXPORT_SYMBOL_GPL(dev_pm_domain_detach);
366
367/**
368 * dev_pm_domain_detach_list - Detach a list of PM domains.
369 * @list: The list of PM domains to detach.
370 *
371 * This function reverse the actions from dev_pm_domain_attach_list().
372 * Typically it should be invoked during the remove phase from drivers.
373 *
374 * Callers must ensure proper synchronization of this function with power
375 * management callbacks.
376 */
377void dev_pm_domain_detach_list(struct dev_pm_domain_list *list)
378{
379	int i;
380
381	if (!list)
382		return;
383
384	for (i = 0; i < list->num_pds; i++) {
385		dev_pm_opp_clear_config(list->opp_tokens[i]);
386		if (list->pd_links[i])
387			device_link_del(list->pd_links[i]);
388		dev_pm_domain_detach(list->pd_devs[i], true);
389	}
390
391	kfree(list->pd_devs);
392	kfree(list);
393}
394EXPORT_SYMBOL_GPL(dev_pm_domain_detach_list);
395
396/**
397 * dev_pm_domain_start - Start the device through its PM domain.
398 * @dev: Device to start.
399 *
400 * This function should typically be called during probe by a subsystem/driver,
401 * when it needs to start its device from the PM domain's perspective. Note
402 * that, it's assumed that the PM domain is already powered on when this
403 * function is called.
404 *
405 * Returns 0 on success and negative error values on failures.
406 */
407int dev_pm_domain_start(struct device *dev)
408{
409	if (dev->pm_domain && dev->pm_domain->start)
410		return dev->pm_domain->start(dev);
411
412	return 0;
413}
414EXPORT_SYMBOL_GPL(dev_pm_domain_start);
415
416/**
417 * dev_pm_domain_set - Set PM domain of a device.
418 * @dev: Device whose PM domain is to be set.
419 * @pd: PM domain to be set, or NULL.
420 *
421 * Sets the PM domain the device belongs to. The PM domain of a device needs
422 * to be set before its probe finishes (it's bound to a driver).
423 *
424 * This function must be called with the device lock held.
425 */
426void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd)
427{
428	if (dev->pm_domain == pd)
429		return;
430
431	WARN(pd && device_is_bound(dev),
432	     "PM domains can only be changed for unbound devices\n");
433	dev->pm_domain = pd;
434	device_pm_check_callbacks(dev);
435}
436EXPORT_SYMBOL_GPL(dev_pm_domain_set);
437
438/**
439 * dev_pm_domain_set_performance_state - Request a new performance state.
440 * @dev: The device to make the request for.
441 * @state: Target performance state for the device.
442 *
443 * This function should be called when a new performance state needs to be
444 * requested for a device that is attached to a PM domain. Note that, the
445 * support for performance scaling for PM domains is optional.
446 *
447 * Returns 0 on success and when performance scaling isn't supported, negative
448 * error code on failure.
449 */
450int dev_pm_domain_set_performance_state(struct device *dev, unsigned int state)
451{
452	if (dev->pm_domain && dev->pm_domain->set_performance_state)
453		return dev->pm_domain->set_performance_state(dev, state);
454
455	return 0;
456}
457EXPORT_SYMBOL_GPL(dev_pm_domain_set_performance_state);