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 | */ |
25 | int 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 | } |
52 | EXPORT_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 | */ |
61 | void 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 | } |
80 | EXPORT_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 | */ |
102 | int 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 | } |
115 | EXPORT_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 | */ |
143 | struct 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 | } |
151 | EXPORT_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 | */ |
160 | struct 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 | } |
168 | EXPORT_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 | */ |
189 | int 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 | |
267 | err_link: |
268 | dev_pm_domain_detach(dev: pd_dev, power_off: true); |
269 | err_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 | } |
277 | EXPORT_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 | */ |
292 | void 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 | } |
297 | EXPORT_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 | */ |
309 | void 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 | } |
322 | EXPORT_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 | */ |
335 | int 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 | } |
342 | EXPORT_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 | */ |
354 | void 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 | } |
364 | EXPORT_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 | */ |
378 | int 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 | } |
385 | EXPORT_SYMBOL_GPL(dev_pm_domain_set_performance_state); |
386 | |