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/kernel.h>
  10 #include <linux/device.h>
  11 #include <linux/io.h>
  12 #include <linux/pm.h>
  13 #include <linux/pm_clock.h>
  14 #include <linux/clk.h>
  15 #include <linux/clkdev.h>
  16 #include <linux/slab.h>
  17 #include <linux/err.h>
  18 #include <linux/pm_runtime.h>
  19
  20 #ifdef CONFIG_PM_CLK
  21
  22 enum pce_status {
  23         PCE_STATUS_NONE = 0,
  24         PCE_STATUS_ACQUIRED,
  25         PCE_STATUS_ENABLED,
  26         PCE_STATUS_ERROR,
  27 };
  28
  29 struct pm_clock_entry {
  30         struct list_head node;
  31         char *con_id;
  32         struct clk *clk;
  33         enum pce_status status;
  34 };
  35
  36 /**
  37  * pm_clk_enable - Enable a clock, reporting any errors
  38  * @dev: The device for the given clock
  39  * @ce: PM clock entry corresponding to the clock.
  40  */
  41 static inline void __pm_clk_enable(struct device *dev, struct pm_clock_entry *ce)
  42 {
  43         int ret;
  44
  45         if (ce->status < PCE_STATUS_ERROR) {
  46                 ret = clk_enable(ce->clk);
  47                 if (!ret)
  48                         ce->status = PCE_STATUS_ENABLED;
  49                 else
  50                         dev_err(dev, "%s: failed to enable clk %p, error %d\n",
  51                                 __func__, ce->clk, ret);
  52         }
  53 }
  54
  55 /**
  56  * pm_clk_acquire - Acquire a device clock.
  57  * @dev: Device whose clock is to be acquired.
  58  * @ce: PM clock entry corresponding to the clock.
  59  */
  60 static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce)
  61 {
  62         if (!ce->clk)
  63                 ce->clk = clk_get(dev, ce->con_id);
  64         if (IS_ERR(ce->clk)) {
  65                 ce->status = PCE_STATUS_ERROR;
  66         } else {
  67                 clk_prepare(ce->clk);
  68                 ce->status = PCE_STATUS_ACQUIRED;
  69                 dev_dbg(dev, "Clock %pC con_id %s managed by runtime PM.\n",
  70                         ce->clk, ce->con_id);
  71         }
  72 }
  73
  74 static int __pm_clk_add(struct device *dev, const char *con_id,
  75                         struct clk *clk)
  76 {
  77         struct pm_subsys_data *psd = dev_to_psd(dev);
  78         struct pm_clock_entry *ce;
  79
  80         if (!psd)
  81                 return -EINVAL;
  82
  83         ce = kzalloc(sizeof(*ce), GFP_KERNEL);
  84         if (!ce)
  85                 return -ENOMEM;
  86
  87         if (con_id) {
  88                 ce->con_id = kstrdup(con_id, GFP_KERNEL);
  89                 if (!ce->con_id) {
  90                         dev_err(dev,
  91                                 "Not enough memory for clock connection ID.\n");
  92                         kfree(ce);
  93                         return -ENOMEM;
  94                 }
  95         } else {
  96                 if (IS_ERR(clk) || !__clk_get(clk)) {
  97                         kfree(ce);
  98                         return -ENOENT;
  99                 }
 100                 ce->clk = clk;
 101         }
 102
 103         pm_clk_acquire(dev, ce);
 104
 105         spin_lock_irq(&psd->lock);
 106         list_add_tail(&ce->node, &psd->clock_list);
 107         spin_unlock_irq(&psd->lock);
 108         return 0;
 109 }
 110
 111 /**
 112  * pm_clk_add - Start using a device clock for power management.
 113  * @dev: Device whose clock is going to be used for power management.
 114  * @con_id: Connection ID of the clock.
 115  *
 116  * Add the clock represented by @con_id to the list of clocks used for
 117  * the power management of @dev.
 118  */
 119 int pm_clk_add(struct device *dev, const char *con_id)
 120 {
 121         return __pm_clk_add(dev, con_id, NULL);
 122 }
 123
 124 /**
 125  * pm_clk_add_clk - Start using a device clock for power management.
 126  * @dev: Device whose clock is going to be used for power management.
 127  * @clk: Clock pointer
 128  *
 129  * Add the clock to the list of clocks used for the power management of @dev.
 130  * It will increment refcount on clock pointer, use clk_put() on it when done.
 131  */
 132 int pm_clk_add_clk(struct device *dev, struct clk *clk)
 133 {
 134         return __pm_clk_add(dev, NULL, clk);
 135 }
 136
 137 /**
 138  * __pm_clk_remove - Destroy PM clock entry.
 139  * @ce: PM clock entry to destroy.
 140  */
 141 static void __pm_clk_remove(struct pm_clock_entry *ce)
 142 {
 143         if (!ce)
 144                 return;
 145
 146         if (ce->status < PCE_STATUS_ERROR) {
 147                 if (ce->status == PCE_STATUS_ENABLED)
 148                         clk_disable(ce->clk);
 149
 150                 if (ce->status >= PCE_STATUS_ACQUIRED) {
 151                         clk_unprepare(ce->clk);
 152                         clk_put(ce->clk);
 153                 }
 154         }
 155
 156         kfree(ce->con_id);
 157         kfree(ce);
 158 }
 159
 160 /**
 161  * pm_clk_remove - Stop using a device clock for power management.
 162  * @dev: Device whose clock should not be used for PM any more.
 163  * @con_id: Connection ID of the clock.
 164  *
 165  * Remove the clock represented by @con_id from the list of clocks used for
 166  * the power management of @dev.
 167  */
 168 void pm_clk_remove(struct device *dev, const char *con_id)
 169 {
 170         struct pm_subsys_data *psd = dev_to_psd(dev);
 171         struct pm_clock_entry *ce;
 172
 173         if (!psd)
 174                 return;
 175
 176         spin_lock_irq(&psd->lock);
 177
 178         list_for_each_entry(ce, &psd->clock_list, node) {
 179                 if (!con_id && !ce->con_id)
 180                         goto remove;
 181                 else if (!con_id || !ce->con_id)
 182                         continue;
 183                 else if (!strcmp(con_id, ce->con_id))
 184                         goto remove;
 185         }
 186
 187         spin_unlock_irq(&psd->lock);
 188         return;
 189
 190  remove:
 191         list_del(&ce->node);
 192         spin_unlock_irq(&psd->lock);
 193
 194         __pm_clk_remove(ce);
 195 }
 196
 197 /**
 198  * pm_clk_init - Initialize a device's list of power management clocks.
 199  * @dev: Device to initialize the list of PM clocks for.
 200  *
 201  * Initialize the lock and clock_list members of the device's pm_subsys_data
 202  * object.
 203  */
 204 void pm_clk_init(struct device *dev)
 205 {
 206         struct pm_subsys_data *psd = dev_to_psd(dev);
 207         if (psd)
 208                 INIT_LIST_HEAD(&psd->clock_list);
 209 }
 210
 211 /**
 212  * pm_clk_create - Create and initialize a device's list of PM clocks.
 213  * @dev: Device to create and initialize the list of PM clocks for.
 214  *
 215  * Allocate a struct pm_subsys_data object, initialize its lock and clock_list
 216  * members and make the @dev's power.subsys_data field point to it.
 217  */
 218 int pm_clk_create(struct device *dev)
 219 {
 220         return dev_pm_get_subsys_data(dev);
 221 }
 222
 223 /**
 224  * pm_clk_destroy - Destroy a device's list of power management clocks.
 225  * @dev: Device to destroy the list of PM clocks for.
 226  *
 227  * Clear the @dev's power.subsys_data field, remove the list of clock entries
 228  * from the struct pm_subsys_data object pointed to by it before and free
 229  * that object.
 230  */
 231 void pm_clk_destroy(struct device *dev)
 232 {
 233         struct pm_subsys_data *psd = dev_to_psd(dev);
 234         struct pm_clock_entry *ce, *c;
 235         struct list_head list;
 236
 237         if (!psd)
 238                 return;
 239
 240         INIT_LIST_HEAD(&list);
 241
 242         spin_lock_irq(&psd->lock);
 243
 244         list_for_each_entry_safe_reverse(ce, c, &psd->clock_list, node)
 245                 list_move(&ce->node, &list);
 246
 247         spin_unlock_irq(&psd->lock);
 248
 249         dev_pm_put_subsys_data(dev);
 250
 251         list_for_each_entry_safe_reverse(ce, c, &list, node) {
 252                 list_del(&ce->node);
 253                 __pm_clk_remove(ce);
 254         }
 255 }
 256
 257 /**
 258  * pm_clk_suspend - Disable clocks in a device's PM clock list.
 259  * @dev: Device to disable the clocks for.
 260  */
 261 int pm_clk_suspend(struct device *dev)
 262 {
 263         struct pm_subsys_data *psd = dev_to_psd(dev);
 264         struct pm_clock_entry *ce;
 265         unsigned long flags;
 266
 267         dev_dbg(dev, "%s()\n", __func__);
 268
 269         if (!psd)
 270                 return 0;
 271
 272         spin_lock_irqsave(&psd->lock, flags);
 273
 274         list_for_each_entry_reverse(ce, &psd->clock_list, node) {
 275                 if (ce->status < PCE_STATUS_ERROR) {
 276                         if (ce->status == PCE_STATUS_ENABLED)
 277                                 clk_disable(ce->clk);
 278                         ce->status = PCE_STATUS_ACQUIRED;
 279                 }
 280         }
 281
 282         spin_unlock_irqrestore(&psd->lock, flags);
 283
 284         return 0;
 285 }
 286
 287 /**
 288  * pm_clk_resume - Enable clocks in a device's PM clock list.
 289  * @dev: Device to enable the clocks for.
 290  */
 291 int pm_clk_resume(struct device *dev)
 292 {
 293         struct pm_subsys_data *psd = dev_to_psd(dev);
 294         struct pm_clock_entry *ce;
 295         unsigned long flags;
 296
 297         dev_dbg(dev, "%s()\n", __func__);
 298
 299         if (!psd)
 300                 return 0;
 301
 302         spin_lock_irqsave(&psd->lock, flags);
 303
 304         list_for_each_entry(ce, &psd->clock_list, node)
 305                 __pm_clk_enable(dev, ce);
 306
 307         spin_unlock_irqrestore(&psd->lock, flags);
 308
 309         return 0;
 310 }
 311
 312 /**
 313  * pm_clk_notify - Notify routine for device addition and removal.
 314  * @nb: Notifier block object this function is a member of.
 315  * @action: Operation being carried out by the caller.
 316  * @data: Device the routine is being run for.
 317  *
 318  * For this function to work, @nb must be a member of an object of type
 319  * struct pm_clk_notifier_block containing all of the requisite data.
 320  * Specifically, the pm_domain member of that object is copied to the device's
 321  * pm_domain field and its con_ids member is used to populate the device's list
 322  * of PM clocks, depending on @action.
 323  *
 324  * If the device's pm_domain field is already populated with a value different
 325  * from the one stored in the struct pm_clk_notifier_block object, the function
 326  * does nothing.
 327  */
 328 static int pm_clk_notify(struct notifier_block *nb,
 329                                  unsigned long action, void *data)
 330 {
 331         struct pm_clk_notifier_block *clknb;
 332         struct device *dev = data;
 333         char **con_id;
 334         int error;
 335
 336         dev_dbg(dev, "%s() %ld\n", __func__, action);
 337
 338         clknb = container_of(nb, struct pm_clk_notifier_block, nb);
 339
 340         switch (action) {
 341         case BUS_NOTIFY_ADD_DEVICE:
 342                 if (dev->pm_domain)
 343                         break;
 344
 345                 error = pm_clk_create(dev);
 346                 if (error)
 347                         break;
 348
 349                 dev->pm_domain = clknb->pm_domain;
 350                 if (clknb->con_ids[0]) {
 351                         for (con_id = clknb->con_ids; *con_id; con_id++)
 352                                 pm_clk_add(dev, *con_id);
 353                 } else {
 354                         pm_clk_add(dev, NULL);
 355                 }
 356
 357                 break;
 358         case BUS_NOTIFY_DEL_DEVICE:
 359                 if (dev->pm_domain != clknb->pm_domain)
 360                         break;
 361
 362                 dev->pm_domain = NULL;
 363                 pm_clk_destroy(dev);
 364                 break;
 365         }
 366
 367         return 0;
 368 }
 369
 370 int pm_clk_runtime_suspend(struct device *dev)
 371 {
 372         int ret;
 373
 374         dev_dbg(dev, "%s\n", __func__);
 375
 376         ret = pm_generic_runtime_suspend(dev);
 377         if (ret) {
 378                 dev_err(dev, "failed to suspend device\n");
 379                 return ret;
 380         }
 381
 382         ret = pm_clk_suspend(dev);
 383         if (ret) {
 384                 dev_err(dev, "failed to suspend clock\n");
 385                 pm_generic_runtime_resume(dev);
 386                 return ret;
 387         }
 388
 389         return 0;
 390 }
 391
 392 int pm_clk_runtime_resume(struct device *dev)
 393 {
 394         int ret;
 395
 396         dev_dbg(dev, "%s\n", __func__);
 397
 398         ret = pm_clk_resume(dev);
 399         if (ret) {
 400                 dev_err(dev, "failed to resume clock\n");
 401                 return ret;
 402         }
 403
 404         return pm_generic_runtime_resume(dev);
 405 }
 406
 407 #else /* !CONFIG_PM_CLK */
 408
 409 /**
 410  * enable_clock - Enable a device clock.
 411  * @dev: Device whose clock is to be enabled.
 412  * @con_id: Connection ID of the clock.
 413  */
 414 static void enable_clock(struct device *dev, const char *con_id)
 415 {
 416         struct clk *clk;
 417
 418         clk = clk_get(dev, con_id);
 419         if (!IS_ERR(clk)) {
 420                 clk_prepare_enable(clk);
 421                 clk_put(clk);
 422                 dev_info(dev, "Runtime PM disabled, clock forced on.\n");
 423         }
 424 }
 425
 426 /**
 427  * disable_clock - Disable a device clock.
 428  * @dev: Device whose clock is to be disabled.
 429  * @con_id: Connection ID of the clock.
 430  */
 431 static void disable_clock(struct device *dev, const char *con_id)
 432 {
 433         struct clk *clk;
 434
 435         clk = clk_get(dev, con_id);
 436         if (!IS_ERR(clk)) {
 437                 clk_disable_unprepare(clk);
 438                 clk_put(clk);
 439                 dev_info(dev, "Runtime PM disabled, clock forced off.\n");
 440         }
 441 }
 442
 443 /**
 444  * pm_clk_notify - Notify routine for device addition and removal.
 445  * @nb: Notifier block object this function is a member of.
 446  * @action: Operation being carried out by the caller.
 447  * @data: Device the routine is being run for.
 448  *
 449  * For this function to work, @nb must be a member of an object of type
 450  * struct pm_clk_notifier_block containing all of the requisite data.
 451  * Specifically, the con_ids member of that object is used to enable or disable
 452  * the device's clocks, depending on @action.
 453  */
 454 static int pm_clk_notify(struct notifier_block *nb,
 455                                  unsigned long action, void *data)
 456 {
 457         struct pm_clk_notifier_block *clknb;
 458         struct device *dev = data;
 459         char **con_id;
 460
 461         dev_dbg(dev, "%s() %ld\n", __func__, action);
 462
 463         clknb = container_of(nb, struct pm_clk_notifier_block, nb);
 464
 465         switch (action) {
 466         case BUS_NOTIFY_BIND_DRIVER:
 467                 if (clknb->con_ids[0]) {
 468                         for (con_id = clknb->con_ids; *con_id; con_id++)
 469                                 enable_clock(dev, *con_id);
 470                 } else {
 471                         enable_clock(dev, NULL);
 472                 }
 473                 break;
 474         case BUS_NOTIFY_UNBOUND_DRIVER:
 475                 if (clknb->con_ids[0]) {
 476                         for (con_id = clknb->con_ids; *con_id; con_id++)
 477                                 disable_clock(dev, *con_id);
 478                 } else {
 479                         disable_clock(dev, NULL);
 480                 }
 481                 break;
 482         }
 483
 484         return 0;
 485 }
 486
 487 #endif /* !CONFIG_PM_CLK */
 488
 489 /**
 490  * pm_clk_add_notifier - Add bus type notifier for power management clocks.
 491  * @bus: Bus type to add the notifier to.
 492  * @clknb: Notifier to be added to the given bus type.
 493  *
 494  * The nb member of @clknb is not expected to be initialized and its
 495  * notifier_call member will be replaced with pm_clk_notify().  However,
 496  * the remaining members of @clknb should be populated prior to calling this
 497  * routine.
 498  */
 499 void pm_clk_add_notifier(struct bus_type *bus,
 500                                  struct pm_clk_notifier_block *clknb)
 501 {
 502         if (!bus || !clknb)
 503                 return;
 504
 505         clknb->nb.notifier_call = pm_clk_notify;
 506         bus_register_notifier(bus, &clknb->nb);
 507 }