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

source code of linux/drivers/base/power/common.c