drivers/base/power/clock_ops.c

   1 /*
   2  * drivers/base/power/clock_ops.c - Generic clock manipulation PM callbacks
   3  *
   4  * Copyright (c) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
   5  *
   6  * This file is released under the GPLv2.
   7  */
   8
   9 #include <linux/init.h>
  10 #include <linux/kernel.h>
  11 #include <linux/device.h>
  12 #include <linux/io.h>
  13 #include <linux/pm.h>
  14 #include <linux/pm_clock.h>
  15 #include <linux/clk.h>
  16 #include <linux/slab.h>
  17 #include <linux/err.h>
  18
  19 #ifdef CONFIG_PM
  20
  21 enum pce_status {
  22         PCE_STATUS_NONE = 0,
  23         PCE_STATUS_ACQUIRED,
  24         PCE_STATUS_ENABLED,
  25         PCE_STATUS_ERROR,
  26 };
  27
  28 struct pm_clock_entry {
  29         struct list_head node;
  30         char *con_id;
  31         struct clk *clk;
  32         enum pce_status status;
  33 };
  34
  35 /**
  36  * pm_clk_acquire - Acquire a device clock.
  37  * @dev: Device whose clock is to be acquired.
  38  * @ce: PM clock entry corresponding to the clock.
  39  */
  40 static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce)
  41 {
  42         ce->clk = clk_get(dev, ce->con_id);
  43         if (IS_ERR(ce->clk)) {
  44                 ce->status = PCE_STATUS_ERROR;
  45         } else {
  46                 ce->status = PCE_STATUS_ACQUIRED;
  47                 dev_dbg(dev, "Clock %s managed by runtime PM.\n", ce->con_id);
  48         }
  49 }
  50
  51 /**
  52  * pm_clk_add - Start using a device clock for power management.
  53  * @dev: Device whose clock is going to be used for power management.
  54  * @con_id: Connection ID of the clock.
  55  *
  56  * Add the clock represented by @con_id to the list of clocks used for
  57  * the power management of @dev.
  58  */
  59 int pm_clk_add(struct device *dev, const char *con_id)
  60 {
  61         struct pm_subsys_data *psd = dev_to_psd(dev);
  62         struct pm_clock_entry *ce;
  63
  64         if (!psd)
  65                 return -EINVAL;
  66
  67         ce = kzalloc(sizeof(*ce), GFP_KERNEL);
  68         if (!ce) {
  69                 dev_err(dev, "Not enough memory for clock entry.\n");
  70                 return -ENOMEM;
  71         }
  72
  73         if (con_id) {
  74                 ce->con_id = kstrdup(con_id, GFP_KERNEL);
  75                 if (!ce->con_id) {
  76                         dev_err(dev,
  77                                 "Not enough memory for clock connection ID.\n");
  78                         kfree(ce);
  79                         return -ENOMEM;
  80                 }
  81         }
  82
  83         pm_clk_acquire(dev, ce);
  84
  85         spin_lock_irq(&psd->lock);
  86         list_add_tail(&ce->node, &psd->clock_list);
  87         spin_unlock_irq(&psd->lock);
  88         return 0;
  89 }
  90
  91 /**
  92  * __pm_clk_remove - Destroy PM clock entry.
  93  * @ce: PM clock entry to destroy.
  94  */
  95 static void __pm_clk_remove(struct pm_clock_entry *ce)
  96 {
  97         if (!ce)
  98                 return;
  99
 100         if (ce->status < PCE_STATUS_ERROR) {
 101                 if (ce->status == PCE_STATUS_ENABLED)
 102                         clk_disable(ce->clk);
 103
 104                 if (ce->status >= PCE_STATUS_ACQUIRED)
 105                         clk_put(ce->clk);
 106         }
 107
 108         kfree(ce->con_id);
 109         kfree(ce);
 110 }
 111
 112 /**
 113  * pm_clk_remove - Stop using a device clock for power management.
 114  * @dev: Device whose clock should not be used for PM any more.
 115  * @con_id: Connection ID of the clock.
 116  *
 117  * Remove the clock represented by @con_id from the list of clocks used for
 118  * the power management of @dev.
 119  */
 120 void pm_clk_remove(struct device *dev, const char *con_id)
 121 {
 122         struct pm_subsys_data *psd = dev_to_psd(dev);
 123         struct pm_clock_entry *ce;
 124
 125         if (!psd)
 126                 return;
 127
 128         spin_lock_irq(&psd->lock);
 129
 130         list_for_each_entry(ce, &psd->clock_list, node) {
 131                 if (!con_id && !ce->con_id)
 132                         goto remove;
 133                 else if (!con_id || !ce->con_id)
 134                         continue;
 135                 else if (!strcmp(con_id, ce->con_id))
 136                         goto remove;
 137         }
 138
 139         spin_unlock_irq(&psd->lock);
 140         return;
 141
 142  remove:
 143         list_del(&ce->node);
 144         spin_unlock_irq(&psd->lock);
 145
 146         __pm_clk_remove(ce);
 147 }
 148
 149 /**
 150  * pm_clk_init - Initialize a device's list of power management clocks.
 151  * @dev: Device to initialize the list of PM clocks for.
 152  *
 153  * Initialize the lock and clock_list members of the device's pm_subsys_data
 154  * object.
 155  */
 156 void pm_clk_init(struct device *dev)
 157 {
 158         struct pm_subsys_data *psd = dev_to_psd(dev);
 159         if (psd)
 160                 INIT_LIST_HEAD(&psd->clock_list);
 161 }
 162
 163 /**
 164  * pm_clk_create - Create and initialize a device's list of PM clocks.
 165  * @dev: Device to create and initialize the list of PM clocks for.
 166  *
 167  * Allocate a struct pm_subsys_data object, initialize its lock and clock_list
 168  * members and make the @dev's power.subsys_data field point to it.
 169  */
 170 int pm_clk_create(struct device *dev)
 171 {
 172         return dev_pm_get_subsys_data(dev);
 173 }
 174
 175 /**
 176  * pm_clk_destroy - Destroy a device's list of power management clocks.
 177  * @dev: Device to destroy the list of PM clocks for.
 178  *
 179  * Clear the @dev's power.subsys_data field, remove the list of clock entries
 180  * from the struct pm_subsys_data object pointed to by it before and free
 181  * that object.
 182  */
 183 void pm_clk_destroy(struct device *dev)
 184 {
 185         struct pm_subsys_data *psd = dev_to_psd(dev);
 186         struct pm_clock_entry *ce, *c;
 187         struct list_head list;
 188
 189         if (!psd)
 190                 return;
 191
 192         INIT_LIST_HEAD(&list);
 193
 194         spin_lock_irq(&psd->lock);
 195
 196         list_for_each_entry_safe_reverse(ce, c, &psd->clock_list, node)
 197                 list_move(&ce->node, &list);
 198
 199         spin_unlock_irq(&psd->lock);
 200
 201         dev_pm_put_subsys_data(dev);
 202
 203         list_for_each_entry_safe_reverse(ce, c, &list, node) {
 204                 list_del(&ce->node);
 205                 __pm_clk_remove(ce);
 206         }
 207 }
 208
 209 #endif /* CONFIG_PM */
 210
 211 #ifdef CONFIG_PM_RUNTIME
 212
 213 /**
 214  * pm_clk_suspend - Disable clocks in a device's PM clock list.
 215  * @dev: Device to disable the clocks for.
 216  */
 217 int pm_clk_suspend(struct device *dev)
 218 {
 219         struct pm_subsys_data *psd = dev_to_psd(dev);
 220         struct pm_clock_entry *ce;
 221         unsigned long flags;
 222
 223         dev_dbg(dev, "%s()\n", __func__);
 224
 225         if (!psd)
 226                 return 0;
 227
 228         spin_lock_irqsave(&psd->lock, flags);
 229
 230         list_for_each_entry_reverse(ce, &psd->clock_list, node) {
 231                 if (ce->status < PCE_STATUS_ERROR) {
 232                         if (ce->status == PCE_STATUS_ENABLED)
 233                                 clk_disable(ce->clk);
 234                         ce->status = PCE_STATUS_ACQUIRED;
 235                 }
 236         }
 237
 238         spin_unlock_irqrestore(&psd->lock, flags);
 239
 240         return 0;
 241 }
 242
 243 /**
 244  * pm_clk_resume - Enable clocks in a device's PM clock list.
 245  * @dev: Device to enable the clocks for.
 246  */
 247 int pm_clk_resume(struct device *dev)
 248 {
 249         struct pm_subsys_data *psd = dev_to_psd(dev);
 250         struct pm_clock_entry *ce;
 251         unsigned long flags;
 252
 253         dev_dbg(dev, "%s()\n", __func__);
 254
 255         if (!psd)
 256                 return 0;
 257
 258         spin_lock_irqsave(&psd->lock, flags);
 259
 260         list_for_each_entry(ce, &psd->clock_list, node) {
 261                 if (ce->status < PCE_STATUS_ERROR) {
 262                         clk_enable(ce->clk);
 263                         ce->status = PCE_STATUS_ENABLED;
 264                 }
 265         }
 266
 267         spin_unlock_irqrestore(&psd->lock, flags);
 268
 269         return 0;
 270 }
 271
 272 /**
 273  * pm_clk_notify - Notify routine for device addition and removal.
 274  * @nb: Notifier block object this function is a member of.
 275  * @action: Operation being carried out by the caller.
 276  * @data: Device the routine is being run for.
 277  *
 278  * For this function to work, @nb must be a member of an object of type
 279  * struct pm_clk_notifier_block containing all of the requisite data.
 280  * Specifically, the pm_domain member of that object is copied to the device's
 281  * pm_domain field and its con_ids member is used to populate the device's list
 282  * of PM clocks, depending on @action.
 283  *
 284  * If the device's pm_domain field is already populated with a value different
 285  * from the one stored in the struct pm_clk_notifier_block object, the function
 286  * does nothing.
 287  */
 288 static int pm_clk_notify(struct notifier_block *nb,
 289                                  unsigned long action, void *data)
 290 {
 291         struct pm_clk_notifier_block *clknb;
 292         struct device *dev = data;
 293         char **con_id;
 294         int error;
 295
 296         dev_dbg(dev, "%s() %ld\n", __func__, action);
 297
 298         clknb = container_of(nb, struct pm_clk_notifier_block, nb);
 299
 300         switch (action) {
 301         case BUS_NOTIFY_ADD_DEVICE:
 302                 if (dev->pm_domain)
 303                         break;
 304
 305                 error = pm_clk_create(dev);
 306                 if (error)
 307                         break;
 308
 309                 dev->pm_domain = clknb->pm_domain;
 310                 if (clknb->con_ids[0]) {
 311                         for (con_id = clknb->con_ids; *con_id; con_id++)
 312                                 pm_clk_add(dev, *con_id);
 313                 } else {
 314                         pm_clk_add(dev, NULL);
 315                 }
 316
 317                 break;
 318         case BUS_NOTIFY_DEL_DEVICE:
 319                 if (dev->pm_domain != clknb->pm_domain)
 320                         break;
 321
 322                 dev->pm_domain = NULL;
 323                 pm_clk_destroy(dev);
 324                 break;
 325         }
 326
 327         return 0;
 328 }
 329
 330 #else /* !CONFIG_PM_RUNTIME */
 331
 332 #ifdef CONFIG_PM
 333
 334 /**
 335  * pm_clk_suspend - Disable clocks in a device's PM clock list.
 336  * @dev: Device to disable the clocks for.
 337  */
 338 int pm_clk_suspend(struct device *dev)
 339 {
 340         struct pm_subsys_data *psd = dev_to_psd(dev);
 341         struct pm_clock_entry *ce;
 342         unsigned long flags;
 343
 344         dev_dbg(dev, "%s()\n", __func__);
 345
 346         /* If there is no driver, the clocks are already disabled. */
 347         if (!psd || !dev->driver)
 348                 return 0;
 349
 350         spin_lock_irqsave(&psd->lock, flags);
 351
 352         list_for_each_entry_reverse(ce, &psd->clock_list, node)
 353                 clk_disable(ce->clk);
 354
 355         spin_unlock_irqrestore(&psd->lock, flags);
 356
 357         return 0;
 358 }
 359
 360 /**
 361  * pm_clk_resume - Enable clocks in a device's PM clock list.
 362  * @dev: Device to enable the clocks for.
 363  */
 364 int pm_clk_resume(struct device *dev)
 365 {
 366         struct pm_subsys_data *psd = dev_to_psd(dev);
 367         struct pm_clock_entry *ce;
 368         unsigned long flags;
 369
 370         dev_dbg(dev, "%s()\n", __func__);
 371
 372         /* If there is no driver, the clocks should remain disabled. */
 373         if (!psd || !dev->driver)
 374                 return 0;
 375
 376         spin_lock_irqsave(&psd->lock, flags);
 377
 378         list_for_each_entry(ce, &psd->clock_list, node)
 379                 clk_enable(ce->clk);
 380
 381         spin_unlock_irqrestore(&psd->lock, flags);
 382
 383         return 0;
 384 }
 385
 386 #endif /* CONFIG_PM */
 387
 388 /**
 389  * enable_clock - Enable a device clock.
 390  * @dev: Device whose clock is to be enabled.
 391  * @con_id: Connection ID of the clock.
 392  */
 393 static void enable_clock(struct device *dev, const char *con_id)
 394 {
 395         struct clk *clk;
 396
 397         clk = clk_get(dev, con_id);
 398         if (!IS_ERR(clk)) {
 399                 clk_enable(clk);
 400                 clk_put(clk);
 401                 dev_info(dev, "Runtime PM disabled, clock forced on.\n");
 402         }
 403 }
 404
 405 /**
 406  * disable_clock - Disable a device clock.
 407  * @dev: Device whose clock is to be disabled.
 408  * @con_id: Connection ID of the clock.
 409  */
 410 static void disable_clock(struct device *dev, const char *con_id)
 411 {
 412         struct clk *clk;
 413
 414         clk = clk_get(dev, con_id);
 415         if (!IS_ERR(clk)) {
 416                 clk_disable(clk);
 417                 clk_put(clk);
 418                 dev_info(dev, "Runtime PM disabled, clock forced off.\n");
 419         }
 420 }
 421
 422 /**
 423  * pm_clk_notify - Notify routine for device addition and removal.
 424  * @nb: Notifier block object this function is a member of.
 425  * @action: Operation being carried out by the caller.
 426  * @data: Device the routine is being run for.
 427  *
 428  * For this function to work, @nb must be a member of an object of type
 429  * struct pm_clk_notifier_block containing all of the requisite data.
 430  * Specifically, the con_ids member of that object is used to enable or disable
 431  * the device's clocks, depending on @action.
 432  */
 433 static int pm_clk_notify(struct notifier_block *nb,
 434                                  unsigned long action, void *data)
 435 {
 436         struct pm_clk_notifier_block *clknb;
 437         struct device *dev = data;
 438         char **con_id;
 439
 440         dev_dbg(dev, "%s() %ld\n", __func__, action);
 441
 442         clknb = container_of(nb, struct pm_clk_notifier_block, nb);
 443
 444         switch (action) {
 445         case BUS_NOTIFY_BIND_DRIVER:
 446                 if (clknb->con_ids[0]) {
 447                         for (con_id = clknb->con_ids; *con_id; con_id++)
 448                                 enable_clock(dev, *con_id);
 449                 } else {
 450                         enable_clock(dev, NULL);
 451                 }
 452                 break;
 453         case BUS_NOTIFY_UNBOUND_DRIVER:
 454                 if (clknb->con_ids[0]) {
 455                         for (con_id = clknb->con_ids; *con_id; con_id++)
 456                                 disable_clock(dev, *con_id);
 457                 } else {
 458                         disable_clock(dev, NULL);
 459                 }
 460                 break;
 461         }
 462
 463         return 0;
 464 }
 465
 466 #endif /* !CONFIG_PM_RUNTIME */
 467
 468 /**
 469  * pm_clk_add_notifier - Add bus type notifier for power management clocks.
 470  * @bus: Bus type to add the notifier to.
 471  * @clknb: Notifier to be added to the given bus type.
 472  *
 473  * The nb member of @clknb is not expected to be initialized and its
 474  * notifier_call member will be replaced with pm_clk_notify().  However,
 475  * the remaining members of @clknb should be populated prior to calling this
 476  * routine.
 477  */
 478 void pm_clk_add_notifier(struct bus_type *bus,
 479                                  struct pm_clk_notifier_block *clknb)
 480 {
 481         if (!bus || !clknb)
 482                 return;
 483
 484         clknb->nb.notifier_call = pm_clk_notify;
 485         bus_register_notifier(bus, &clknb->nb);
 486 }