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(sizeof(*psd), GFP_KERNEL); 30 if (!psd) 31 return -ENOMEM; 32 33 spin_lock_irq(&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(&dev->power.lock); 46 47 /* kfree() verifies that its argument is nonzero. */ 48 kfree(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(&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(&dev->power.lock); 78 kfree(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(-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(-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, "power-domains", 214 "#power-domain-cells"); 215 } 216 217 if (num_pds <= 0) 218 return 0; 219 220 pds = devm_kzalloc(dev, sizeof(*pds), GFP_KERNEL); 221 if (!pds) 222 return -ENOMEM; 223 224 pds->pd_devs = devm_kcalloc(dev, num_pds, sizeof(*pds->pd_devs), 225 GFP_KERNEL); 226 if (!pds->pd_devs) 227 return -ENOMEM; 228 229 pds->pd_links = devm_kcalloc(dev, num_pds, 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(pd_dev)) { 244 ret = pd_dev ? PTR_ERR(pd_dev) : -ENODEV; 245 goto err_attach; 246 } 247 248 if (link_flags) { 249 struct device_link *link; 250 251 link = device_link_add(dev, pd_dev, 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(pd_dev, true); 269err_attach: 270 while (--i >= 0) { 271 if (pds->pd_links[i]) 272 device_link_del(pds->pd_links[i]); 273 dev_pm_domain_detach(pds->pd_devs[i], 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(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