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(lock: &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(lock: &dev->power.lock);
47
48 /* kfree() verifies that its argument is nonzero. */
49 kfree(objp: 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(lock: &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(lock: &dev->power.lock);
79 kfree(objp: 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, power_on: !!(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(error: -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(error: -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, list_name: "power-domains",
219 cells_name: "#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(ptr: pd_dev)) {
249 ret = pd_dev ? PTR_ERR(ptr: 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: &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(consumer: dev, supplier: pd_dev, flags: 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(token: pds->opp_tokens[i]);
287 dev_pm_domain_detach(dev: pd_dev, power_off: true);
288err_attach:
289 while (--i >= 0) {
290 dev_pm_opp_clear_config(token: pds->opp_tokens[i]);
291 if (pds->pd_links[i])
292 device_link_del(link: pds->pd_links[i]);
293 dev_pm_domain_detach(dev: pds->pd_devs[i], power_off: true);
294 }
295 kfree(objp: pds->pd_devs);
296free_pds:
297 kfree(objp: 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(token: list->opp_tokens[i]);
386 if (list->pd_links[i])
387 device_link_del(link: list->pd_links[i]);
388 dev_pm_domain_detach(list->pd_devs[i], true);
389 }
390
391 kfree(objp: list->pd_devs);
392 kfree(objp: 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);
458