drivers/base/power/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  */
  26 int 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 }
  53 EXPORT_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  */
  62 void 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 }
  81 EXPORT_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  * @power_on: Used to indicate whether we should power on the device.
  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  */
 103 int dev_pm_domain_attach(struct device *dev, bool power_on)
 104 {
 105         int ret;
 106
 107         if (dev->pm_domain)
 108                 return 0;
 109
 110         ret = acpi_dev_pm_attach(dev, power_on);
 111         if (!ret)
 112                 ret = genpd_dev_pm_attach(dev);
 113
 114         return ret < 0 ? ret : 0;
 115 }
 116 EXPORT_SYMBOL_GPL(dev_pm_domain_attach);
 117
 118 /**
 119  * dev_pm_domain_attach_by_id - Associate a device with one of its PM domains.
 120  * @dev: The device used to lookup the PM domain.
 121  * @index: The index of the PM domain.
 122  *
 123  * As @dev may only be attached to a single PM domain, the backend PM domain
 124  * provider creates a virtual device to attach instead. If attachment succeeds,
 125  * the ->detach() callback in the struct dev_pm_domain are assigned by the
 126  * corresponding backend attach function, as to deal with detaching of the
 127  * created virtual device.
 128  *
 129  * This function should typically be invoked by a driver during the probe phase,
 130  * in case its device requires power management through multiple PM domains. The
 131  * driver may benefit from using the received device, to configure device-links
 132  * towards its original device. Depending on the use-case and if needed, the
 133  * links may be dynamically changed by the driver, which allows it to control
 134  * the power to the PM domains independently from each other.
 135  *
 136  * Callers must ensure proper synchronization of this function with power
 137  * management callbacks.
 138  *
 139  * Returns the virtual created device when successfully attached to its PM
 140  * domain, NULL in case @dev don't need a PM domain, else an ERR_PTR().
 141  * Note that, to detach the returned virtual device, the driver shall call
 142  * dev_pm_domain_detach() on it, typically during the remove phase.
 143  */
 144 struct device *dev_pm_domain_attach_by_id(struct device *dev,
 145                                           unsigned int index)
 146 {
 147         if (dev->pm_domain)
 148                 return ERR_PTR(-EEXIST);
 149
 150         return genpd_dev_pm_attach_by_id(dev, index);
 151 }
 152 EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_id);
 153
 154 /**
 155  * dev_pm_domain_attach_by_name - Associate a device with one of its PM domains.
 156  * @dev: The device used to lookup the PM domain.
 157  * @name: The name of the PM domain.
 158  *
 159  * For a detailed function description, see dev_pm_domain_attach_by_id().
 160  */
 161 struct device *dev_pm_domain_attach_by_name(struct device *dev,
 162                                             const char *name)
 163 {
 164         if (dev->pm_domain)
 165                 return ERR_PTR(-EEXIST);
 166
 167         return genpd_dev_pm_attach_by_name(dev, name);
 168 }
 169 EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_name);
 170
 171 /**
 172  * dev_pm_domain_attach_list - Associate a device with its PM domains.
 173  * @dev: The device used to lookup the PM domains for.
 174  * @data: The data used for attaching to the PM domains.
 175  * @list: An out-parameter with an allocated list of attached PM domains.
 176  *
 177  * This function helps to attach a device to its multiple PM domains. The
 178  * caller, which is typically a driver's probe function, may provide a list of
 179  * names for the PM domains that we should try to attach the device to, but it
 180  * may also provide an empty list, in case the attach should be done for all of
 181  * the available PM domains.
 182  *
 183  * Callers must ensure proper synchronization of this function with power
 184  * management callbacks.
 185  *
 186  * Returns the number of attached PM domains or a negative error code in case of
 187  * a failure. Note that, to detach the list of PM domains, the driver shall call
 188  * dev_pm_domain_detach_list(), typically during the remove phase.
 189  */
 190 int dev_pm_domain_attach_list(struct device *dev,
 191                               const struct dev_pm_domain_attach_data *data,
 192                               struct dev_pm_domain_list **list)
 193 {
 194         struct device_node *np = dev->of_node;
 195         struct dev_pm_domain_list *pds;
 196         struct device *pd_dev = NULL;
 197         int ret, i, num_pds = 0;
 198         bool by_id = true;
 199         size_t size;
 200         u32 pd_flags = data ? data->pd_flags : 0;
 201         u32 link_flags = pd_flags & PD_FLAG_NO_DEV_LINK ? 0 :
 202                         DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME;
 203
 204         if (dev->pm_domain)
 205                 return -EEXIST;
 206
 207         /* For now this is limited to OF based platforms. */
 208         if (!np)
 209                 return 0;
 210
 211         if (data && data->pd_names) {
 212                 num_pds = data->num_pd_names;
 213                 by_id = false;
 214         } else {
 215                 num_pds = of_count_phandle_with_args(np, "power-domains",
 216                                                      "#power-domain-cells");
 217         }
 218
 219         if (num_pds <= 0)
 220                 return 0;
 221
 222         pds = kzalloc(sizeof(*pds), GFP_KERNEL);
 223         if (!pds)
 224                 return -ENOMEM;
 225
 226         size = sizeof(*pds->pd_devs) + sizeof(*pds->pd_links) +
 227                sizeof(*pds->opp_tokens);
 228         pds->pd_devs = kcalloc(num_pds, size, GFP_KERNEL);
 229         if (!pds->pd_devs) {
 230                 ret = -ENOMEM;
 231                 goto free_pds;
 232         }
 233         pds->pd_links = (void *)(pds->pd_devs + num_pds);
 234         pds->opp_tokens = (void *)(pds->pd_links + num_pds);
 235
 236         if (link_flags && pd_flags & PD_FLAG_DEV_LINK_ON)
 237                 link_flags |= DL_FLAG_RPM_ACTIVE;
 238
 239         for (i = 0; i < num_pds; i++) {
 240                 if (by_id)
 241                         pd_dev = dev_pm_domain_attach_by_id(dev, i);
 242                 else
 243                         pd_dev = dev_pm_domain_attach_by_name(dev,
 244                                                         data->pd_names[i]);
 245                 if (IS_ERR_OR_NULL(pd_dev)) {
 246                         ret = pd_dev ? PTR_ERR(pd_dev) : -ENODEV;
 247                         goto err_attach;
 248                 }
 249
 250                 if (pd_flags & PD_FLAG_REQUIRED_OPP) {
 251                         struct dev_pm_opp_config config = {
 252                                 .required_dev = pd_dev,
 253                                 .required_dev_index = i,
 254                         };
 255
 256                         ret = dev_pm_opp_set_config(dev, &config);
 257                         if (ret < 0)
 258                                 goto err_link;
 259
 260                         pds->opp_tokens[i] = ret;
 261                 }
 262
 263                 if (link_flags) {
 264                         struct device_link *link;
 265
 266                         link = device_link_add(dev, pd_dev, link_flags);
 267                         if (!link) {
 268                                 ret = -ENODEV;
 269                                 goto err_link;
 270                         }
 271
 272                         pds->pd_links[i] = link;
 273                 }
 274
 275                 pds->pd_devs[i] = pd_dev;
 276         }
 277
 278         pds->num_pds = num_pds;
 279         *list = pds;
 280         return num_pds;
 281
 282 err_link:
 283         dev_pm_opp_clear_config(pds->opp_tokens[i]);
 284         dev_pm_domain_detach(pd_dev, true);
 285 err_attach:
 286         while (--i >= 0) {
 287                 dev_pm_opp_clear_config(pds->opp_tokens[i]);
 288                 if (pds->pd_links[i])
 289                         device_link_del(pds->pd_links[i]);
 290                 dev_pm_domain_detach(pds->pd_devs[i], true);
 291         }
 292         kfree(pds->pd_devs);
 293 free_pds:
 294         kfree(pds);
 295         return ret;
 296 }
 297 EXPORT_SYMBOL_GPL(dev_pm_domain_attach_list);
 298
 299 /**
 300  * devm_pm_domain_detach_list - devres-enabled version of dev_pm_domain_detach_list.
 301  * @_list: The list of PM domains to detach.
 302  *
 303  * This function reverse the actions from devm_pm_domain_attach_list().
 304  * it will be invoked during the remove phase from drivers implicitly if driver
 305  * uses devm_pm_domain_attach_list() to attach the PM domains.
 306  */
 307 static void devm_pm_domain_detach_list(void *_list)
 308 {
 309         struct dev_pm_domain_list *list = _list;
 310
 311         dev_pm_domain_detach_list(list);
 312 }
 313
 314 /**
 315  * devm_pm_domain_attach_list - devres-enabled version of dev_pm_domain_attach_list
 316  * @dev: The device used to lookup the PM domains for.
 317  * @data: The data used for attaching to the PM domains.
 318  * @list: An out-parameter with an allocated list of attached PM domains.
 319  *
 320  * NOTE: this will also handle calling devm_pm_domain_detach_list() for
 321  * you during remove phase.
 322  *
 323  * Returns the number of attached PM domains or a negative error code in case of
 324  * a failure.
 325  */
 326 int devm_pm_domain_attach_list(struct device *dev,
 327                                const struct dev_pm_domain_attach_data *data,
 328                                struct dev_pm_domain_list **list)
 329 {
 330         int ret, num_pds;
 331
 332         num_pds = dev_pm_domain_attach_list(dev, data, list);
 333         if (num_pds <= 0)
 334                 return num_pds;
 335
 336         ret = devm_add_action_or_reset(dev, devm_pm_domain_detach_list, *list);
 337         if (ret)
 338                 return ret;
 339
 340         return num_pds;
 341 }
 342 EXPORT_SYMBOL_GPL(devm_pm_domain_attach_list);
 343
 344 /**
 345  * dev_pm_domain_detach - Detach a device from its PM domain.
 346  * @dev: Device to detach.
 347  * @power_off: Used to indicate whether we should power off the device.
 348  *
 349  * This functions will reverse the actions from dev_pm_domain_attach(),
 350  * dev_pm_domain_attach_by_id() and dev_pm_domain_attach_by_name(), thus it
 351  * detaches @dev from its PM domain.  Typically it should be invoked during the
 352  * remove phase, either from subsystem level code or from drivers.
 353  *
 354  * Callers must ensure proper synchronization of this function with power
 355  * management callbacks.
 356  */
 357 void dev_pm_domain_detach(struct device *dev, bool power_off)
 358 {
 359         if (dev->pm_domain && dev->pm_domain->detach)
 360                 dev->pm_domain->detach(dev, power_off);
 361 }
 362 EXPORT_SYMBOL_GPL(dev_pm_domain_detach);
 363
 364 /**
 365  * dev_pm_domain_detach_list - Detach a list of PM domains.
 366  * @list: The list of PM domains to detach.
 367  *
 368  * This function reverse the actions from dev_pm_domain_attach_list().
 369  * Typically it should be invoked during the remove phase from drivers.
 370  *
 371  * Callers must ensure proper synchronization of this function with power
 372  * management callbacks.
 373  */
 374 void dev_pm_domain_detach_list(struct dev_pm_domain_list *list)
 375 {
 376         int i;
 377
 378         if (!list)
 379                 return;
 380
 381         for (i = 0; i < list->num_pds; i++) {
 382                 dev_pm_opp_clear_config(list->opp_tokens[i]);
 383                 if (list->pd_links[i])
 384                         device_link_del(list->pd_links[i]);
 385                 dev_pm_domain_detach(list->pd_devs[i], true);
 386         }
 387
 388         kfree(list->pd_devs);
 389         kfree(list);
 390 }
 391 EXPORT_SYMBOL_GPL(dev_pm_domain_detach_list);
 392
 393 /**
 394  * dev_pm_domain_start - Start the device through its PM domain.
 395  * @dev: Device to start.
 396  *
 397  * This function should typically be called during probe by a subsystem/driver,
 398  * when it needs to start its device from the PM domain's perspective. Note
 399  * that, it's assumed that the PM domain is already powered on when this
 400  * function is called.
 401  *
 402  * Returns 0 on success and negative error values on failures.
 403  */
 404 int dev_pm_domain_start(struct device *dev)
 405 {
 406         if (dev->pm_domain && dev->pm_domain->start)
 407                 return dev->pm_domain->start(dev);
 408
 409         return 0;
 410 }
 411 EXPORT_SYMBOL_GPL(dev_pm_domain_start);
 412
 413 /**
 414  * dev_pm_domain_set - Set PM domain of a device.
 415  * @dev: Device whose PM domain is to be set.
 416  * @pd: PM domain to be set, or NULL.
 417  *
 418  * Sets the PM domain the device belongs to. The PM domain of a device needs
 419  * to be set before its probe finishes (it's bound to a driver).
 420  *
 421  * This function must be called with the device lock held.
 422  */
 423 void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd)
 424 {
 425         if (dev->pm_domain == pd)
 426                 return;
 427
 428         WARN(pd && device_is_bound(dev),
 429              "PM domains can only be changed for unbound devices\n");
 430         dev->pm_domain = pd;
 431         device_pm_check_callbacks(dev);
 432 }
 433 EXPORT_SYMBOL_GPL(dev_pm_domain_set);
 434
 435 /**
 436  * dev_pm_domain_set_performance_state - Request a new performance state.
 437  * @dev: The device to make the request for.
 438  * @state: Target performance state for the device.
 439  *
 440  * This function should be called when a new performance state needs to be
 441  * requested for a device that is attached to a PM domain. Note that, the
 442  * support for performance scaling for PM domains is optional.
 443  *
 444  * Returns 0 on success and when performance scaling isn't supported, negative
 445  * error code on failure.
 446  */
 447 int dev_pm_domain_set_performance_state(struct device *dev, unsigned int state)
 448 {
 449         if (dev->pm_domain && dev->pm_domain->set_performance_state)
 450                 return dev->pm_domain->set_performance_state(dev, state);
 451
 452         return 0;
 453 }
 454 EXPORT_SYMBOL_GPL(dev_pm_domain_set_performance_state);