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                 clk_prepare(ce->clk);
  47                 ce->status = PCE_STATUS_ACQUIRED;
  48                 dev_dbg(dev, "Clock %s managed by runtime PM.\n", ce->con_id);
  49         }
  50 }
  51
  52 /**
  53  * pm_clk_add - Start using a device clock for power management.
  54  * @dev: Device whose clock is going to be used for power management.
  55  * @con_id: Connection ID of the clock.
  56  *
  57  * Add the clock represented by @con_id to the list of clocks used for
  58  * the power management of @dev.
  59  */
  60 int pm_clk_add(struct device *dev, const char *con_id)
  61 {
  62         struct pm_subsys_data *psd = dev_to_psd(dev);
  63         struct pm_clock_entry *ce;
  64
  65         if (!psd)
  66                 return -EINVAL;
  67
  68         ce = kzalloc(sizeof(*ce), GFP_KERNEL);
  69         if (!ce) {
  70                 dev_err(dev, "Not enough memory for clock entry.\n");
  71                 return -ENOMEM;
  72         }
  73
  74         if (con_id) {
  75                 ce->con_id = kstrdup(con_id, GFP_KERNEL);
  76                 if (!ce->con_id) {
  77                         dev_err(dev,
  78                                 "Not enough memory for clock connection ID.\n");
  79                         kfree(ce);
  80                         return -ENOMEM;
  81                 }
  82         }
  83
  84         pm_clk_acquire(dev, ce);
  85
  86         spin_lock_irq(&psd->lock);
  87         list_add_tail(&ce->node, &psd->clock_list);
  88         spin_unlock_irq(&psd->lock);
  89         return 0;
  90 }
  91
  92 /**
  93  * __pm_clk_remove - Destroy PM clock entry.
  94  * @ce: PM clock entry to destroy.
  95  */
  96 static void __pm_clk_remove(struct pm_clock_entry *ce)
  97 {
  98         if (!ce)
  99                 return;
 100
 101         if (ce->status < PCE_STATUS_ERROR) {
 102                 if (ce->status == PCE_STATUS_ENABLED)
 103                         clk_disable(ce->clk);
 104
 105                 if (ce->status >= PCE_STATUS_ACQUIRED) {
 106                         clk_unprepare(ce->clk);
 107                         clk_put(ce->clk);
 108                 }
 109         }
 110
 111         kfree(ce->con_id);
 112         kfree(ce);
 113 }
 114
 115 /**
 116  * pm_clk_remove - Stop using a device clock for power management.
 117  * @dev: Device whose clock should not be used for PM any more.
 118  * @con_id: Connection ID of the clock.
 119  *
 120  * Remove the clock represented by @con_id from the list of clocks used for
 121  * the power management of @dev.
 122  */
 123 void pm_clk_remove(struct device *dev, const char *con_id)
 124 {
 125         struct pm_subsys_data *psd = dev_to_psd(dev);
 126         struct pm_clock_entry *ce;
 127
 128         if (!psd)
 129                 return;
 130
 131         spin_lock_irq(&psd->lock);
 132
 133         list_for_each_entry(ce, &psd->clock_list, node) {
 134                 if (!con_id && !ce->con_id)
 135                         goto remove;
 136                 else if (!con_id || !ce->con_id)
 137                         continue;
 138                 else if (!strcmp(con_id, ce->con_id))
 139                         goto remove;
 140         }
 141
 142         spin_unlock_irq(&psd->lock);
 143         return;
 144
 145  remove:
 146         list_del(&ce->node);
 147         spin_unlock_irq(&psd->lock);
 148
 149         __pm_clk_remove(ce);
 150 }
 151
 152 /**
 153  * pm_clk_init - Initialize a device's list of power management clocks.
 154  * @dev: Device to initialize the list of PM clocks for.
 155  *
 156  * Initialize the lock and clock_list members of the device's pm_subsys_data
 157  * object.
 158  */
 159 void pm_clk_init(struct device *dev)
 160 {
 161         struct pm_subsys_data *psd = dev_to_psd(dev);
 162         if (psd)
 163                 INIT_LIST_HEAD(&psd->clock_list);
 164 }
 165
 166 /**
 167  * pm_clk_create - Create and initialize a device's list of PM clocks.
 168  * @dev: Device to create and initialize the list of PM clocks for.
 169  *
 170  * Allocate a struct pm_subsys_data object, initialize its lock and clock_list
 171  * members and make the @dev's power.subsys_data field point to it.
 172  */
 173 int pm_clk_create(struct device *dev)
 174 {
 175         return dev_pm_get_subsys_data(dev);
 176 }
 177
 178 /**
 179  * pm_clk_destroy - Destroy a device's list of power management clocks.
 180  * @dev: Device to destroy the list of PM clocks for.
 181  *
 182  * Clear the @dev's power.subsys_data field, remove the list of clock entries
 183  * from the struct pm_subsys_data object pointed to by it before and free
 184  * that object.
 185  */
 186 void pm_clk_destroy(struct device *dev)
 187 {
 188         struct pm_subsys_data *psd = dev_to_psd(dev);
 189         struct pm_clock_entry *ce, *c;
 190         struct list_head list;
 191
 192         if (!psd)
 193                 return;
 194
 195         INIT_LIST_HEAD(&list);
 196
 197         spin_lock_irq(&psd->lock);
 198
 199         list_for_each_entry_safe_reverse(ce, c, &psd->clock_list, node)
 200                 list_move(&ce->node, &list);
 201
 202         spin_unlock_irq(&psd->lock);
 203
 204         dev_pm_put_subsys_data(dev);
 205
 206         list_for_each_entry_safe_reverse(ce, c, &list, node) {
 207                 list_del(&ce->node);
 208                 __pm_clk_remove(ce);
 209         }
 210 }
 211
 212 #endif /* CONFIG_PM */
 213
 214 #ifdef CONFIG_PM_RUNTIME
 215
 216 /**
 217  * pm_clk_suspend - Disable clocks in a device's PM clock list.
 218  * @dev: Device to disable the clocks for.
 219  */
 220 int pm_clk_suspend(struct device *dev)
 221 {
 222         struct pm_subsys_data *psd = dev_to_psd(dev);
 223         struct pm_clock_entry *ce;
 224         unsigned long flags;
 225
 226         dev_dbg(dev, "%s()\n", __func__);
 227
 228         if (!psd)
 229                 return 0;
 230
 231         spin_lock_irqsave(&psd->lock, flags);
 232
 233         list_for_each_entry_reverse(ce, &psd->clock_list, node) {
 234                 if (ce->status < PCE_STATUS_ERROR) {
 235                         if (ce->status == PCE_STATUS_ENABLED)
 236                                 clk_disable(ce->clk);
 237                         ce->status = PCE_STATUS_ACQUIRED;
 238                 }
 239         }
 240
 241         spin_unlock_irqrestore(&psd->lock, flags);
 242
 243         return 0;
 244 }
 245
 246 /**
 247  * pm_clk_resume - Enable clocks in a device's PM clock list.
 248  * @dev: Device to enable the clocks for.
 249  */
 250 int pm_clk_resume(struct device *dev)
 251 {
 252         struct pm_subsys_data *psd = dev_to_psd(dev);
 253         struct pm_clock_entry *ce;
 254         unsigned long flags;
 255
 256         dev_dbg(dev, "%s()\n", __func__);
 257
 258         if (!psd)
 259                 return 0;
 260
 261         spin_lock_irqsave(&psd->lock, flags);
 262
 263         list_for_each_entry(ce, &psd->clock_list, node) {
 264                 if (ce->status < PCE_STATUS_ERROR) {
 265                         clk_enable(ce->clk);
 266                         ce->status = PCE_STATUS_ENABLED;
 267                 }
 268         }
 269
 270         spin_unlock_irqrestore(&psd->lock, flags);
 271
 272         return 0;
 273 }
 274
 275 /**
 276  * pm_clk_notify - Notify routine for device addition and removal.
 277  * @nb: Notifier block object this function is a member of.
 278  * @action: Operation being carried out by the caller.
 279  * @data: Device the routine is being run for.
 280  *
 281  * For this function to work, @nb must be a member of an object of type
 282  * struct pm_clk_notifier_block containing all of the requisite data.
 283  * Specifically, the pm_domain member of that object is copied to the device's
 284  * pm_domain field and its con_ids member is used to populate the device's list
 285  * of PM clocks, depending on @action.
 286  *
 287  * If the device's pm_domain field is already populated with a value different
 288  * from the one stored in the struct pm_clk_notifier_block object, the function
 289  * does nothing.
 290  */
 291 static int pm_clk_notify(struct notifier_block *nb,
 292                                  unsigned long action, void *data)
 293 {
 294         struct pm_clk_notifier_block *clknb;
 295         struct device *dev = data;
 296         char **con_id;
 297         int error;
 298
 299         dev_dbg(dev, "%s() %ld\n", __func__, action);
 300
 301         clknb = container_of(nb, struct pm_clk_notifier_block, nb);
 302
 303         switch (action) {
 304         case BUS_NOTIFY_ADD_DEVICE:
 305                 if (dev->pm_domain)
 306                         break;
 307
 308                 error = pm_clk_create(dev);
 309                 if (error)
 310                         break;
 311
 312                 dev->pm_domain = clknb->pm_domain;
 313                 if (clknb->con_ids[0]) {
 314                         for (con_id = clknb->con_ids; *con_id; con_id++)
 315                                 pm_clk_add(dev, *con_id);
 316                 } else {
 317                         pm_clk_add(dev, NULL);
 318                 }
 319
 320                 break;
 321         case BUS_NOTIFY_DEL_DEVICE:
 322                 if (dev->pm_domain != clknb->pm_domain)
 323                         break;
 324
 325                 dev->pm_domain = NULL;
 326                 pm_clk_destroy(dev);
 327                 break;
 328         }
 329
 330         return 0;
 331 }
 332
 333 #else /* !CONFIG_PM_RUNTIME */
 334
 335 #ifdef CONFIG_PM
 336
 337 /**
 338  * pm_clk_suspend - Disable clocks in a device's PM clock list.
 339  * @dev: Device to disable the clocks for.
 340  */
 341 int pm_clk_suspend(struct device *dev)
 342 {
 343         struct pm_subsys_data *psd = dev_to_psd(dev);
 344         struct pm_clock_entry *ce;
 345         unsigned long flags;
 346
 347         dev_dbg(dev, "%s()\n", __func__);
 348
 349         /* If there is no driver, the clocks are already disabled. */
 350         if (!psd || !dev->driver)
 351                 return 0;
 352
 353         spin_lock_irqsave(&psd->lock, flags);
 354
 355         list_for_each_entry_reverse(ce, &psd->clock_list, node)
 356                 clk_disable(ce->clk);
 357
 358         spin_unlock_irqrestore(&psd->lock, flags);
 359
 360         return 0;
 361 }
 362
 363 /**
 364  * pm_clk_resume - Enable clocks in a device's PM clock list.
 365  * @dev: Device to enable the clocks for.
 366  */
 367 int pm_clk_resume(struct device *dev)
 368 {
 369         struct pm_subsys_data *psd = dev_to_psd(dev);
 370         struct pm_clock_entry *ce;
 371         unsigned long flags;
 372
 373         dev_dbg(dev, "%s()\n", __func__);
 374
 375         /* If there is no driver, the clocks should remain disabled. */
 376         if (!psd || !dev->driver)
 377                 return 0;
 378
 379         spin_lock_irqsave(&psd->lock, flags);
 380
 381         list_for_each_entry(ce, &psd->clock_list, node)
 382                 clk_enable(ce->clk);
 383
 384         spin_unlock_irqrestore(&psd->lock, flags);
 385
 386         return 0;
 387 }
 388
 389 #endif /* CONFIG_PM */
 390
 391 /**
 392  * enable_clock - Enable a device clock.
 393  * @dev: Device whose clock is to be enabled.
 394  * @con_id: Connection ID of the clock.
 395  */
 396 static void enable_clock(struct device *dev, const char *con_id)
 397 {
 398         struct clk *clk;
 399
 400         clk = clk_get(dev, con_id);
 401         if (!IS_ERR(clk)) {
 402                 clk_prepare_enable(clk);
 403                 clk_put(clk);
 404                 dev_info(dev, "Runtime PM disabled, clock forced on.\n");
 405         }
 406 }
 407
 408 /**
 409  * disable_clock - Disable a device clock.
 410  * @dev: Device whose clock is to be disabled.
 411  * @con_id: Connection ID of the clock.
 412  */
 413 static void disable_clock(struct device *dev, const char *con_id)
 414 {
 415         struct clk *clk;
 416
 417         clk = clk_get(dev, con_id);
 418         if (!IS_ERR(clk)) {
 419                 clk_disable_unprepare(clk);
 420                 clk_put(clk);
 421                 dev_info(dev, "Runtime PM disabled, clock forced off.\n");
 422         }
 423 }
 424
 425 /**
 426  * pm_clk_notify - Notify routine for device addition and removal.
 427  * @nb: Notifier block object this function is a member of.
 428  * @action: Operation being carried out by the caller.
 429  * @data: Device the routine is being run for.
 430  *
 431  * For this function to work, @nb must be a member of an object of type
 432  * struct pm_clk_notifier_block containing all of the requisite data.
 433  * Specifically, the con_ids member of that object is used to enable or disable
 434  * the device's clocks, depending on @action.
 435  */
 436 static int pm_clk_notify(struct notifier_block *nb,
 437                                  unsigned long action, void *data)
 438 {
 439         struct pm_clk_notifier_block *clknb;
 440         struct device *dev = data;
 441         char **con_id;
 442
 443         dev_dbg(dev, "%s() %ld\n", __func__, action);
 444
 445         clknb = container_of(nb, struct pm_clk_notifier_block, nb);
 446
 447         switch (action) {
 448         case BUS_NOTIFY_BIND_DRIVER:
 449                 if (clknb->con_ids[0]) {
 450                         for (con_id = clknb->con_ids; *con_id; con_id++)
 451                                 enable_clock(dev, *con_id);
 452                 } else {
 453                         enable_clock(dev, NULL);
 454                 }
 455                 break;
 456         case BUS_NOTIFY_UNBOUND_DRIVER:
 457                 if (clknb->con_ids[0]) {
 458                         for (con_id = clknb->con_ids; *con_id; con_id++)
 459                                 disable_clock(dev, *con_id);
 460                 } else {
 461                         disable_clock(dev, NULL);
 462                 }
 463                 break;
 464         }
 465
 466         return 0;
 467 }
 468
 469 #endif /* !CONFIG_PM_RUNTIME */
 470
 471 /**
 472  * pm_clk_add_notifier - Add bus type notifier for power management clocks.
 473  * @bus: Bus type to add the notifier to.
 474  * @clknb: Notifier to be added to the given bus type.
 475  *
 476  * The nb member of @clknb is not expected to be initialized and its
 477  * notifier_call member will be replaced with pm_clk_notify().  However,
 478  * the remaining members of @clknb should be populated prior to calling this
 479  * routine.
 480  */
 481 void pm_clk_add_notifier(struct bus_type *bus,
 482                                  struct pm_clk_notifier_block *clknb)
 483 {
 484         if (!bus || !clknb)
 485                 return;
 486
 487         clknb->nb.notifier_call = pm_clk_notify;
 488         bus_register_notifier(bus, &clknb->nb);
 489 }