arch/arm/mach-omap2/clockdomain.c

   1 /*
   2  * OMAP2/3/4 clockdomain framework functions
   3  *
   4  * Copyright (C) 2008-2010 Texas Instruments, Inc.
   5  * Copyright (C) 2008-2010 Nokia Corporation
   6  *
   7  * Written by Paul Walmsley and Jouni Högander
   8  * Added OMAP4 specific support by Abhijit Pagare <abhijitpagare@ti.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14 #undef DEBUG
  15
  16 #include <linux/kernel.h>
  17 #include <linux/device.h>
  18 #include <linux/list.h>
  19 #include <linux/errno.h>
  20 #include <linux/delay.h>
  21 #include <linux/clk.h>
  22 #include <linux/limits.h>
  23 #include <linux/err.h>
  24
  25 #include <linux/io.h>
  26
  27 #include <linux/bitops.h>
  28
  29 #include <plat/clock.h>
  30 #include "clockdomain.h"
  31
  32 /* clkdm_list contains all registered struct clockdomains */
  33 static LIST_HEAD(clkdm_list);
  34
  35 /* array of clockdomain deps to be added/removed when clkdm in hwsup mode */
  36 static struct clkdm_autodep *autodeps;
  37
  38 static struct clkdm_ops *arch_clkdm;
  39
  40 /* Private functions */
  41
  42 static struct clockdomain *_clkdm_lookup(const char *name)
  43 {
  44         struct clockdomain *clkdm, *temp_clkdm;
  45
  46         if (!name)
  47                 return NULL;
  48
  49         clkdm = NULL;
  50
  51         list_for_each_entry(temp_clkdm, &clkdm_list, node) {
  52                 if (!strcmp(name, temp_clkdm->name)) {
  53                         clkdm = temp_clkdm;
  54                         break;
  55                 }
  56         }
  57
  58         return clkdm;
  59 }
  60
  61 /**
  62  * _clkdm_register - register a clockdomain
  63  * @clkdm: struct clockdomain * to register
  64  *
  65  * Adds a clockdomain to the internal clockdomain list.
  66  * Returns -EINVAL if given a null pointer, -EEXIST if a clockdomain is
  67  * already registered by the provided name, or 0 upon success.
  68  */
  69 static int _clkdm_register(struct clockdomain *clkdm)
  70 {
  71         struct powerdomain *pwrdm;
  72
  73         if (!clkdm || !clkdm->name)
  74                 return -EINVAL;
  75
  76         if (!omap_chip_is(clkdm->omap_chip))
  77                 return -EINVAL;
  78
  79         pwrdm = pwrdm_lookup(clkdm->pwrdm.name);
  80         if (!pwrdm) {
  81                 pr_err("clockdomain: %s: powerdomain %s does not exist\n",
  82                         clkdm->name, clkdm->pwrdm.name);
  83                 return -EINVAL;
  84         }
  85         clkdm->pwrdm.ptr = pwrdm;
  86
  87         /* Verify that the clockdomain is not already registered */
  88         if (_clkdm_lookup(clkdm->name))
  89                 return -EEXIST;
  90
  91         list_add(&clkdm->node, &clkdm_list);
  92
  93         pwrdm_add_clkdm(pwrdm, clkdm);
  94
  95         pr_debug("clockdomain: registered %s\n", clkdm->name);
  96
  97         return 0;
  98 }
  99
 100 /* _clkdm_deps_lookup - look up the specified clockdomain in a clkdm list */
 101 static struct clkdm_dep *_clkdm_deps_lookup(struct clockdomain *clkdm,
 102                                             struct clkdm_dep *deps)
 103 {
 104         struct clkdm_dep *cd;
 105
 106         if (!clkdm || !deps || !omap_chip_is(clkdm->omap_chip))
 107                 return ERR_PTR(-EINVAL);
 108
 109         for (cd = deps; cd->clkdm_name; cd++) {
 110                 if (!omap_chip_is(cd->omap_chip))
 111                         continue;
 112
 113                 if (!cd->clkdm && cd->clkdm_name)
 114                         cd->clkdm = _clkdm_lookup(cd->clkdm_name);
 115
 116                 if (cd->clkdm == clkdm)
 117                         break;
 118         }
 119
 120         if (!cd->clkdm_name)
 121                 return ERR_PTR(-ENOENT);
 122
 123         return cd;
 124 }
 125
 126 /*
 127  * _autodep_lookup - resolve autodep clkdm names to clkdm pointers; store
 128  * @autodep: struct clkdm_autodep * to resolve
 129  *
 130  * Resolve autodep clockdomain names to clockdomain pointers via
 131  * clkdm_lookup() and store the pointers in the autodep structure.  An
 132  * "autodep" is a clockdomain sleep/wakeup dependency that is
 133  * automatically added and removed whenever clocks in the associated
 134  * clockdomain are enabled or disabled (respectively) when the
 135  * clockdomain is in hardware-supervised mode.  Meant to be called
 136  * once at clockdomain layer initialization, since these should remain
 137  * fixed for a particular architecture.  No return value.
 138  *
 139  * XXX autodeps are deprecated and should be removed at the earliest
 140  * opportunity
 141  */
 142 static void _autodep_lookup(struct clkdm_autodep *autodep)
 143 {
 144         struct clockdomain *clkdm;
 145
 146         if (!autodep)
 147                 return;
 148
 149         if (!omap_chip_is(autodep->omap_chip))
 150                 return;
 151
 152         clkdm = clkdm_lookup(autodep->clkdm.name);
 153         if (!clkdm) {
 154                 pr_err("clockdomain: autodeps: clockdomain %s does not exist\n",
 155                          autodep->clkdm.name);
 156                 clkdm = ERR_PTR(-ENOENT);
 157         }
 158         autodep->clkdm.ptr = clkdm;
 159 }
 160
 161 /*
 162  * _clkdm_add_autodeps - add auto sleepdeps/wkdeps to clkdm upon clock enable
 163  * @clkdm: struct clockdomain *
 164  *
 165  * Add the "autodep" sleep & wakeup dependencies to clockdomain 'clkdm'
 166  * in hardware-supervised mode.  Meant to be called from clock framework
 167  * when a clock inside clockdomain 'clkdm' is enabled.  No return value.
 168  *
 169  * XXX autodeps are deprecated and should be removed at the earliest
 170  * opportunity
 171  */
 172 void _clkdm_add_autodeps(struct clockdomain *clkdm)
 173 {
 174         struct clkdm_autodep *autodep;
 175
 176         if (!autodeps || clkdm->flags & CLKDM_NO_AUTODEPS)
 177                 return;
 178
 179         for (autodep = autodeps; autodep->clkdm.ptr; autodep++) {
 180                 if (IS_ERR(autodep->clkdm.ptr))
 181                         continue;
 182
 183                 if (!omap_chip_is(autodep->omap_chip))
 184                         continue;
 185
 186                 pr_debug("clockdomain: adding %s sleepdep/wkdep for "
 187                          "clkdm %s\n", autodep->clkdm.ptr->name,
 188                          clkdm->name);
 189
 190                 clkdm_add_sleepdep(clkdm, autodep->clkdm.ptr);
 191                 clkdm_add_wkdep(clkdm, autodep->clkdm.ptr);
 192         }
 193 }
 194
 195 /*
 196  * _clkdm_add_autodeps - remove auto sleepdeps/wkdeps from clkdm
 197  * @clkdm: struct clockdomain *
 198  *
 199  * Remove the "autodep" sleep & wakeup dependencies from clockdomain 'clkdm'
 200  * in hardware-supervised mode.  Meant to be called from clock framework
 201  * when a clock inside clockdomain 'clkdm' is disabled.  No return value.
 202  *
 203  * XXX autodeps are deprecated and should be removed at the earliest
 204  * opportunity
 205  */
 206 void _clkdm_del_autodeps(struct clockdomain *clkdm)
 207 {
 208         struct clkdm_autodep *autodep;
 209
 210         if (!autodeps || clkdm->flags & CLKDM_NO_AUTODEPS)
 211                 return;
 212
 213         for (autodep = autodeps; autodep->clkdm.ptr; autodep++) {
 214                 if (IS_ERR(autodep->clkdm.ptr))
 215                         continue;
 216
 217                 if (!omap_chip_is(autodep->omap_chip))
 218                         continue;
 219
 220                 pr_debug("clockdomain: removing %s sleepdep/wkdep for "
 221                          "clkdm %s\n", autodep->clkdm.ptr->name,
 222                          clkdm->name);
 223
 224                 clkdm_del_sleepdep(clkdm, autodep->clkdm.ptr);
 225                 clkdm_del_wkdep(clkdm, autodep->clkdm.ptr);
 226         }
 227 }
 228
 229 /**
 230  * _resolve_clkdm_deps() - resolve clkdm_names in @clkdm_deps to clkdms
 231  * @clkdm: clockdomain that we are resolving dependencies for
 232  * @clkdm_deps: ptr to array of struct clkdm_deps to resolve
 233  *
 234  * Iterates through @clkdm_deps, looking up the struct clockdomain named by
 235  * clkdm_name and storing the clockdomain pointer in the struct clkdm_dep.
 236  * No return value.
 237  */
 238 static void _resolve_clkdm_deps(struct clockdomain *clkdm,
 239                                 struct clkdm_dep *clkdm_deps)
 240 {
 241         struct clkdm_dep *cd;
 242
 243         for (cd = clkdm_deps; cd && cd->clkdm_name; cd++) {
 244                 if (!omap_chip_is(cd->omap_chip))
 245                         continue;
 246                 if (cd->clkdm)
 247                         continue;
 248                 cd->clkdm = _clkdm_lookup(cd->clkdm_name);
 249
 250                 WARN(!cd->clkdm, "clockdomain: %s: could not find clkdm %s while resolving dependencies - should never happen",
 251                      clkdm->name, cd->clkdm_name);
 252         }
 253 }
 254
 255 /* Public functions */
 256
 257 /**
 258  * clkdm_init - set up the clockdomain layer
 259  * @clkdms: optional pointer to an array of clockdomains to register
 260  * @init_autodeps: optional pointer to an array of autodeps to register
 261  * @custom_funcs: func pointers for arch specific implementations
 262  *
 263  * Set up internal state.  If a pointer to an array of clockdomains
 264  * @clkdms was supplied, loop through the list of clockdomains,
 265  * register all that are available on the current platform. Similarly,
 266  * if a pointer to an array of clockdomain autodependencies
 267  * @init_autodeps was provided, register those.  No return value.
 268  */
 269 void clkdm_init(struct clockdomain **clkdms,
 270                 struct clkdm_autodep *init_autodeps,
 271                 struct clkdm_ops *custom_funcs)
 272 {
 273         struct clockdomain **c = NULL;
 274         struct clockdomain *clkdm;
 275         struct clkdm_autodep *autodep = NULL;
 276
 277         if (!custom_funcs)
 278                 WARN(1, "No custom clkdm functions registered\n");
 279         else
 280                 arch_clkdm = custom_funcs;
 281
 282         if (clkdms)
 283                 for (c = clkdms; *c; c++)
 284                         _clkdm_register(*c);
 285
 286         autodeps = init_autodeps;
 287         if (autodeps)
 288                 for (autodep = autodeps; autodep->clkdm.ptr; autodep++)
 289                         _autodep_lookup(autodep);
 290
 291         /*
 292          * Put all clockdomains into software-supervised mode; PM code
 293          * should later enable hardware-supervised mode as appropriate
 294          */
 295         list_for_each_entry(clkdm, &clkdm_list, node) {
 296                 if (clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)
 297                         clkdm_wakeup(clkdm);
 298                 else if (clkdm->flags & CLKDM_CAN_DISABLE_AUTO)
 299                         clkdm_deny_idle(clkdm);
 300
 301                 _resolve_clkdm_deps(clkdm, clkdm->wkdep_srcs);
 302                 clkdm_clear_all_wkdeps(clkdm);
 303
 304                 _resolve_clkdm_deps(clkdm, clkdm->sleepdep_srcs);
 305                 clkdm_clear_all_sleepdeps(clkdm);
 306         }
 307 }
 308
 309 /**
 310  * clkdm_lookup - look up a clockdomain by name, return a pointer
 311  * @name: name of clockdomain
 312  *
 313  * Find a registered clockdomain by its name @name.  Returns a pointer
 314  * to the struct clockdomain if found, or NULL otherwise.
 315  */
 316 struct clockdomain *clkdm_lookup(const char *name)
 317 {
 318         struct clockdomain *clkdm, *temp_clkdm;
 319
 320         if (!name)
 321                 return NULL;
 322
 323         clkdm = NULL;
 324
 325         list_for_each_entry(temp_clkdm, &clkdm_list, node) {
 326                 if (!strcmp(name, temp_clkdm->name)) {
 327                         clkdm = temp_clkdm;
 328                         break;
 329                 }
 330         }
 331
 332         return clkdm;
 333 }
 334
 335 /**
 336  * clkdm_for_each - call function on each registered clockdomain
 337  * @fn: callback function *
 338  *
 339  * Call the supplied function @fn for each registered clockdomain.
 340  * The callback function @fn can return anything but 0 to bail
 341  * out early from the iterator.  The callback function is called with
 342  * the clkdm_mutex held, so no clockdomain structure manipulation
 343  * functions should be called from the callback, although hardware
 344  * clockdomain control functions are fine.  Returns the last return
 345  * value of the callback function, which should be 0 for success or
 346  * anything else to indicate failure; or -EINVAL if the function pointer
 347  * is null.
 348  */
 349 int clkdm_for_each(int (*fn)(struct clockdomain *clkdm, void *user),
 350                         void *user)
 351 {
 352         struct clockdomain *clkdm;
 353         int ret = 0;
 354
 355         if (!fn)
 356                 return -EINVAL;
 357
 358         list_for_each_entry(clkdm, &clkdm_list, node) {
 359                 ret = (*fn)(clkdm, user);
 360                 if (ret)
 361                         break;
 362         }
 363
 364         return ret;
 365 }
 366
 367
 368 /**
 369  * clkdm_get_pwrdm - return a ptr to the pwrdm that this clkdm resides in
 370  * @clkdm: struct clockdomain *
 371  *
 372  * Return a pointer to the struct powerdomain that the specified clockdomain
 373  * @clkdm exists in, or returns NULL if @clkdm is NULL.
 374  */
 375 struct powerdomain *clkdm_get_pwrdm(struct clockdomain *clkdm)
 376 {
 377         if (!clkdm)
 378                 return NULL;
 379
 380         return clkdm->pwrdm.ptr;
 381 }
 382
 383
 384 /* Hardware clockdomain control */
 385
 386 /**
 387  * clkdm_add_wkdep - add a wakeup dependency from clkdm2 to clkdm1
 388  * @clkdm1: wake this struct clockdomain * up (dependent)
 389  * @clkdm2: when this struct clockdomain * wakes up (source)
 390  *
 391  * When the clockdomain represented by @clkdm2 wakes up, wake up
 392  * @clkdm1. Implemented in hardware on the OMAP, this feature is
 393  * designed to reduce wakeup latency of the dependent clockdomain @clkdm1.
 394  * Returns -EINVAL if presented with invalid clockdomain pointers,
 395  * -ENOENT if @clkdm2 cannot wake up clkdm1 in hardware, or 0 upon
 396  * success.
 397  */
 398 int clkdm_add_wkdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
 399 {
 400         struct clkdm_dep *cd;
 401         int ret = 0;
 402
 403         if (!clkdm1 || !clkdm2)
 404                 return -EINVAL;
 405
 406         cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
 407         if (IS_ERR(cd))
 408                 ret = PTR_ERR(cd);
 409
 410         if (!arch_clkdm || !arch_clkdm->clkdm_add_wkdep)
 411                 ret = -EINVAL;
 412
 413         if (ret) {
 414                 pr_debug("clockdomain: hardware cannot set/clear wake up of "
 415                          "%s when %s wakes up\n", clkdm1->name, clkdm2->name);
 416                 return ret;
 417         }
 418
 419         if (atomic_inc_return(&cd->wkdep_usecount) == 1) {
 420                 pr_debug("clockdomain: hardware will wake up %s when %s wakes "
 421                          "up\n", clkdm1->name, clkdm2->name);
 422
 423                 ret = arch_clkdm->clkdm_add_wkdep(clkdm1, clkdm2);
 424         }
 425
 426         return ret;
 427 }
 428
 429 /**
 430  * clkdm_del_wkdep - remove a wakeup dependency from clkdm2 to clkdm1
 431  * @clkdm1: wake this struct clockdomain * up (dependent)
 432  * @clkdm2: when this struct clockdomain * wakes up (source)
 433  *
 434  * Remove a wakeup dependency causing @clkdm1 to wake up when @clkdm2
 435  * wakes up.  Returns -EINVAL if presented with invalid clockdomain
 436  * pointers, -ENOENT if @clkdm2 cannot wake up clkdm1 in hardware, or
 437  * 0 upon success.
 438  */
 439 int clkdm_del_wkdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
 440 {
 441         struct clkdm_dep *cd;
 442         int ret = 0;
 443
 444         if (!clkdm1 || !clkdm2)
 445                 return -EINVAL;
 446
 447         cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
 448         if (IS_ERR(cd))
 449                 ret = PTR_ERR(cd);
 450
 451         if (!arch_clkdm || !arch_clkdm->clkdm_del_wkdep)
 452                 ret = -EINVAL;
 453
 454         if (ret) {
 455                 pr_debug("clockdomain: hardware cannot set/clear wake up of "
 456                          "%s when %s wakes up\n", clkdm1->name, clkdm2->name);
 457                 return ret;
 458         }
 459
 460         if (atomic_dec_return(&cd->wkdep_usecount) == 0) {
 461                 pr_debug("clockdomain: hardware will no longer wake up %s "
 462                          "after %s wakes up\n", clkdm1->name, clkdm2->name);
 463
 464                 ret = arch_clkdm->clkdm_del_wkdep(clkdm1, clkdm2);
 465         }
 466
 467         return ret;
 468 }
 469
 470 /**
 471  * clkdm_read_wkdep - read wakeup dependency state from clkdm2 to clkdm1
 472  * @clkdm1: wake this struct clockdomain * up (dependent)
 473  * @clkdm2: when this struct clockdomain * wakes up (source)
 474  *
 475  * Return 1 if a hardware wakeup dependency exists wherein @clkdm1 will be
 476  * awoken when @clkdm2 wakes up; 0 if dependency is not set; -EINVAL
 477  * if either clockdomain pointer is invalid; or -ENOENT if the hardware
 478  * is incapable.
 479  *
 480  * REVISIT: Currently this function only represents software-controllable
 481  * wakeup dependencies.  Wakeup dependencies fixed in hardware are not
 482  * yet handled here.
 483  */
 484 int clkdm_read_wkdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
 485 {
 486         struct clkdm_dep *cd;
 487         int ret = 0;
 488
 489         if (!clkdm1 || !clkdm2)
 490                 return -EINVAL;
 491
 492         cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
 493         if (IS_ERR(cd))
 494                 ret = PTR_ERR(cd);
 495
 496         if (!arch_clkdm || !arch_clkdm->clkdm_read_wkdep)
 497                 ret = -EINVAL;
 498
 499         if (ret) {
 500                 pr_debug("clockdomain: hardware cannot set/clear wake up of "
 501                          "%s when %s wakes up\n", clkdm1->name, clkdm2->name);
 502                 return ret;
 503         }
 504
 505         /* XXX It's faster to return the atomic wkdep_usecount */
 506         return arch_clkdm->clkdm_read_wkdep(clkdm1, clkdm2);
 507 }
 508
 509 /**
 510  * clkdm_clear_all_wkdeps - remove all wakeup dependencies from target clkdm
 511  * @clkdm: struct clockdomain * to remove all wakeup dependencies from
 512  *
 513  * Remove all inter-clockdomain wakeup dependencies that could cause
 514  * @clkdm to wake.  Intended to be used during boot to initialize the
 515  * PRCM to a known state, after all clockdomains are put into swsup idle
 516  * and woken up.  Returns -EINVAL if @clkdm pointer is invalid, or
 517  * 0 upon success.
 518  */
 519 int clkdm_clear_all_wkdeps(struct clockdomain *clkdm)
 520 {
 521         if (!clkdm)
 522                 return -EINVAL;
 523
 524         if (!arch_clkdm || !arch_clkdm->clkdm_clear_all_wkdeps)
 525                 return -EINVAL;
 526
 527         return arch_clkdm->clkdm_clear_all_wkdeps(clkdm);
 528 }
 529
 530 /**
 531  * clkdm_add_sleepdep - add a sleep dependency from clkdm2 to clkdm1
 532  * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
 533  * @clkdm2: when this struct clockdomain * is active (source)
 534  *
 535  * Prevent @clkdm1 from automatically going inactive (and then to
 536  * retention or off) if @clkdm2 is active.  Returns -EINVAL if
 537  * presented with invalid clockdomain pointers or called on a machine
 538  * that does not support software-configurable hardware sleep
 539  * dependencies, -ENOENT if the specified dependency cannot be set in
 540  * hardware, or 0 upon success.
 541  */
 542 int clkdm_add_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
 543 {
 544         struct clkdm_dep *cd;
 545         int ret = 0;
 546
 547         if (!clkdm1 || !clkdm2)
 548                 return -EINVAL;
 549
 550         cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
 551         if (IS_ERR(cd))
 552                 ret = PTR_ERR(cd);
 553
 554         if (!arch_clkdm || !arch_clkdm->clkdm_add_sleepdep)
 555                 ret = -EINVAL;
 556
 557         if (ret) {
 558                 pr_debug("clockdomain: hardware cannot set/clear sleep "
 559                          "dependency affecting %s from %s\n", clkdm1->name,
 560                          clkdm2->name);
 561                 return ret;
 562         }
 563
 564         if (atomic_inc_return(&cd->sleepdep_usecount) == 1) {
 565                 pr_debug("clockdomain: will prevent %s from sleeping if %s "
 566                          "is active\n", clkdm1->name, clkdm2->name);
 567
 568                 ret = arch_clkdm->clkdm_add_sleepdep(clkdm1, clkdm2);
 569         }
 570
 571         return ret;
 572 }
 573
 574 /**
 575  * clkdm_del_sleepdep - remove a sleep dependency from clkdm2 to clkdm1
 576  * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
 577  * @clkdm2: when this struct clockdomain * is active (source)
 578  *
 579  * Allow @clkdm1 to automatically go inactive (and then to retention or
 580  * off), independent of the activity state of @clkdm2.  Returns -EINVAL
 581  * if presented with invalid clockdomain pointers or called on a machine
 582  * that does not support software-configurable hardware sleep dependencies,
 583  * -ENOENT if the specified dependency cannot be cleared in hardware, or
 584  * 0 upon success.
 585  */
 586 int clkdm_del_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
 587 {
 588         struct clkdm_dep *cd;
 589         int ret = 0;
 590
 591         if (!clkdm1 || !clkdm2)
 592                 return -EINVAL;
 593
 594         cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
 595         if (IS_ERR(cd))
 596                 ret = PTR_ERR(cd);
 597
 598         if (!arch_clkdm || !arch_clkdm->clkdm_del_sleepdep)
 599                 ret = -EINVAL;
 600
 601         if (ret) {
 602                 pr_debug("clockdomain: hardware cannot set/clear sleep "
 603                          "dependency affecting %s from %s\n", clkdm1->name,
 604                          clkdm2->name);
 605                 return ret;
 606         }
 607
 608         if (atomic_dec_return(&cd->sleepdep_usecount) == 0) {
 609                 pr_debug("clockdomain: will no longer prevent %s from "
 610                          "sleeping if %s is active\n", clkdm1->name,
 611                          clkdm2->name);
 612
 613                 ret = arch_clkdm->clkdm_del_sleepdep(clkdm1, clkdm2);
 614         }
 615
 616         return ret;
 617 }
 618
 619 /**
 620  * clkdm_read_sleepdep - read sleep dependency state from clkdm2 to clkdm1
 621  * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
 622  * @clkdm2: when this struct clockdomain * is active (source)
 623  *
 624  * Return 1 if a hardware sleep dependency exists wherein @clkdm1 will
 625  * not be allowed to automatically go inactive if @clkdm2 is active;
 626  * 0 if @clkdm1's automatic power state inactivity transition is independent
 627  * of @clkdm2's; -EINVAL if either clockdomain pointer is invalid or called
 628  * on a machine that does not support software-configurable hardware sleep
 629  * dependencies; or -ENOENT if the hardware is incapable.
 630  *
 631  * REVISIT: Currently this function only represents software-controllable
 632  * sleep dependencies.  Sleep dependencies fixed in hardware are not
 633  * yet handled here.
 634  */
 635 int clkdm_read_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
 636 {
 637         struct clkdm_dep *cd;
 638         int ret = 0;
 639
 640         if (!clkdm1 || !clkdm2)
 641                 return -EINVAL;
 642
 643         cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
 644         if (IS_ERR(cd))
 645                 ret = PTR_ERR(cd);
 646
 647         if (!arch_clkdm || !arch_clkdm->clkdm_read_sleepdep)
 648                 ret = -EINVAL;
 649
 650         if (ret) {
 651                 pr_debug("clockdomain: hardware cannot set/clear sleep "
 652                          "dependency affecting %s from %s\n", clkdm1->name,
 653                          clkdm2->name);
 654                 return ret;
 655         }
 656
 657         /* XXX It's faster to return the atomic sleepdep_usecount */
 658         return arch_clkdm->clkdm_read_sleepdep(clkdm1, clkdm2);
 659 }
 660
 661 /**
 662  * clkdm_clear_all_sleepdeps - remove all sleep dependencies from target clkdm
 663  * @clkdm: struct clockdomain * to remove all sleep dependencies from
 664  *
 665  * Remove all inter-clockdomain sleep dependencies that could prevent
 666  * @clkdm from idling.  Intended to be used during boot to initialize the
 667  * PRCM to a known state, after all clockdomains are put into swsup idle
 668  * and woken up.  Returns -EINVAL if @clkdm pointer is invalid, or
 669  * 0 upon success.
 670  */
 671 int clkdm_clear_all_sleepdeps(struct clockdomain *clkdm)
 672 {
 673         if (!clkdm)
 674                 return -EINVAL;
 675
 676         if (!arch_clkdm || !arch_clkdm->clkdm_clear_all_sleepdeps)
 677                 return -EINVAL;
 678
 679         return arch_clkdm->clkdm_clear_all_sleepdeps(clkdm);
 680 }
 681
 682 /**
 683  * clkdm_sleep - force clockdomain sleep transition
 684  * @clkdm: struct clockdomain *
 685  *
 686  * Instruct the CM to force a sleep transition on the specified
 687  * clockdomain @clkdm.  Returns -EINVAL if @clkdm is NULL or if
 688  * clockdomain does not support software-initiated sleep; 0 upon
 689  * success.
 690  */
 691 int clkdm_sleep(struct clockdomain *clkdm)
 692 {
 693         if (!clkdm)
 694                 return -EINVAL;
 695
 696         if (!(clkdm->flags & CLKDM_CAN_FORCE_SLEEP)) {
 697                 pr_debug("clockdomain: %s does not support forcing "
 698                          "sleep via software\n", clkdm->name);
 699                 return -EINVAL;
 700         }
 701
 702         if (!arch_clkdm || !arch_clkdm->clkdm_sleep)
 703                 return -EINVAL;
 704
 705         pr_debug("clockdomain: forcing sleep on %s\n", clkdm->name);
 706
 707         return arch_clkdm->clkdm_sleep(clkdm);
 708 }
 709
 710 /**
 711  * clkdm_wakeup - force clockdomain wakeup transition
 712  * @clkdm: struct clockdomain *
 713  *
 714  * Instruct the CM to force a wakeup transition on the specified
 715  * clockdomain @clkdm.  Returns -EINVAL if @clkdm is NULL or if the
 716  * clockdomain does not support software-controlled wakeup; 0 upon
 717  * success.
 718  */
 719 int clkdm_wakeup(struct clockdomain *clkdm)
 720 {
 721         if (!clkdm)
 722                 return -EINVAL;
 723
 724         if (!(clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)) {
 725                 pr_debug("clockdomain: %s does not support forcing "
 726                          "wakeup via software\n", clkdm->name);
 727                 return -EINVAL;
 728         }
 729
 730         if (!arch_clkdm || !arch_clkdm->clkdm_wakeup)
 731                 return -EINVAL;
 732
 733         pr_debug("clockdomain: forcing wakeup on %s\n", clkdm->name);
 734
 735         return arch_clkdm->clkdm_wakeup(clkdm);
 736 }
 737
 738 /**
 739  * clkdm_allow_idle - enable hwsup idle transitions for clkdm
 740  * @clkdm: struct clockdomain *
 741  *
 742  * Allow the hardware to automatically switch the clockdomain @clkdm into
 743  * active or idle states, as needed by downstream clocks.  If the
 744  * clockdomain has any downstream clocks enabled in the clock
 745  * framework, wkdep/sleepdep autodependencies are added; this is so
 746  * device drivers can read and write to the device.  No return value.
 747  */
 748 void clkdm_allow_idle(struct clockdomain *clkdm)
 749 {
 750         if (!clkdm)
 751                 return;
 752
 753         if (!(clkdm->flags & CLKDM_CAN_ENABLE_AUTO)) {
 754                 pr_debug("clock: automatic idle transitions cannot be enabled "
 755                          "on clockdomain %s\n", clkdm->name);
 756                 return;
 757         }
 758
 759         if (!arch_clkdm || !arch_clkdm->clkdm_allow_idle)
 760                 return;
 761
 762         pr_debug("clockdomain: enabling automatic idle transitions for %s\n",
 763                  clkdm->name);
 764
 765         arch_clkdm->clkdm_allow_idle(clkdm);
 766         pwrdm_clkdm_state_switch(clkdm);
 767 }
 768
 769 /**
 770  * clkdm_deny_idle - disable hwsup idle transitions for clkdm
 771  * @clkdm: struct clockdomain *
 772  *
 773  * Prevent the hardware from automatically switching the clockdomain
 774  * @clkdm into inactive or idle states.  If the clockdomain has
 775  * downstream clocks enabled in the clock framework, wkdep/sleepdep
 776  * autodependencies are removed.  No return value.
 777  */
 778 void clkdm_deny_idle(struct clockdomain *clkdm)
 779 {
 780         if (!clkdm)
 781                 return;
 782
 783         if (!(clkdm->flags & CLKDM_CAN_DISABLE_AUTO)) {
 784                 pr_debug("clockdomain: automatic idle transitions cannot be "
 785                          "disabled on %s\n", clkdm->name);
 786                 return;
 787         }
 788
 789         if (!arch_clkdm || !arch_clkdm->clkdm_deny_idle)
 790                 return;
 791
 792         pr_debug("clockdomain: disabling automatic idle transitions for %s\n",
 793                  clkdm->name);
 794
 795         arch_clkdm->clkdm_deny_idle(clkdm);
 796 }
 797
 798
 799 /* Clockdomain-to-clock framework interface code */
 800
 801 /**
 802  * clkdm_clk_enable - add an enabled downstream clock to this clkdm
 803  * @clkdm: struct clockdomain *
 804  * @clk: struct clk * of the enabled downstream clock
 805  *
 806  * Increment the usecount of the clockdomain @clkdm and ensure that it
 807  * is awake before @clk is enabled.  Intended to be called by
 808  * clk_enable() code.  If the clockdomain is in software-supervised
 809  * idle mode, force the clockdomain to wake.  If the clockdomain is in
 810  * hardware-supervised idle mode, add clkdm-pwrdm autodependencies, to
 811  * ensure that devices in the clockdomain can be read from/written to
 812  * by on-chip processors.  Returns -EINVAL if passed null pointers;
 813  * returns 0 upon success or if the clockdomain is in hwsup idle mode.
 814  */
 815 int clkdm_clk_enable(struct clockdomain *clkdm, struct clk *clk)
 816 {
 817         /*
 818          * XXX Rewrite this code to maintain a list of enabled
 819          * downstream clocks for debugging purposes?
 820          */
 821
 822         if (!clkdm || !clk)
 823                 return -EINVAL;
 824
 825         if (!arch_clkdm || !arch_clkdm->clkdm_clk_enable)
 826                 return -EINVAL;
 827
 828         if (atomic_inc_return(&clkdm->usecount) > 1)
 829                 return 0;
 830
 831         /* Clockdomain now has one enabled downstream clock */
 832
 833         pr_debug("clockdomain: clkdm %s: clk %s now enabled\n", clkdm->name,
 834                  clk->name);
 835
 836         arch_clkdm->clkdm_clk_enable(clkdm);
 837         pwrdm_wait_transition(clkdm->pwrdm.ptr);
 838         pwrdm_clkdm_state_switch(clkdm);
 839
 840         return 0;
 841 }
 842
 843 /**
 844  * clkdm_clk_disable - remove an enabled downstream clock from this clkdm
 845  * @clkdm: struct clockdomain *
 846  * @clk: struct clk * of the disabled downstream clock
 847  *
 848  * Decrement the usecount of this clockdomain @clkdm when @clk is
 849  * disabled.  Intended to be called by clk_disable() code.  If the
 850  * clockdomain usecount goes to 0, put the clockdomain to sleep
 851  * (software-supervised mode) or remove the clkdm autodependencies
 852  * (hardware-supervised mode).  Returns -EINVAL if passed null
 853  * pointers; -ERANGE if the @clkdm usecount underflows and debugging
 854  * is enabled; or returns 0 upon success or if the clockdomain is in
 855  * hwsup idle mode.
 856  */
 857 int clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk)
 858 {
 859         /*
 860          * XXX Rewrite this code to maintain a list of enabled
 861          * downstream clocks for debugging purposes?
 862          */
 863
 864         if (!clkdm || !clk)
 865                 return -EINVAL;
 866
 867         if (!arch_clkdm || !arch_clkdm->clkdm_clk_disable)
 868                 return -EINVAL;
 869
 870 #ifdef DEBUG
 871         if (atomic_read(&clkdm->usecount) == 0) {
 872                 WARN_ON(1); /* underflow */
 873                 return -ERANGE;
 874         }
 875 #endif
 876
 877         if (atomic_dec_return(&clkdm->usecount) > 0)
 878                 return 0;
 879
 880         /* All downstream clocks of this clockdomain are now disabled */
 881
 882         pr_debug("clockdomain: clkdm %s: clk %s now disabled\n", clkdm->name,
 883                  clk->name);
 884
 885         arch_clkdm->clkdm_clk_disable(clkdm);
 886         pwrdm_clkdm_state_switch(clkdm);
 887
 888         return 0;
 889 }
 890