arch/arm/mach-omap2/clockdomain.c

   1 /*
   2  * OMAP2/3/4 clockdomain framework functions
   3  *
   4  * Copyright (C) 2008-2011 Texas Instruments, Inc.
   5  * Copyright (C) 2008-2011 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/string.h>
  21 #include <linux/delay.h>
  22 #include <linux/clk.h>
  23 #include <linux/limits.h>
  24 #include <linux/err.h>
  25
  26 #include <linux/io.h>
  27
  28 #include <linux/bitops.h>
  29
  30 #include <plat/clock.h>
  31 #include "clockdomain.h"
  32
  33 /* clkdm_list contains all registered struct clockdomains */
  34 static LIST_HEAD(clkdm_list);
  35
  36 /* array of clockdomain deps to be added/removed when clkdm in hwsup mode */
  37 static struct clkdm_autodep *autodeps;
  38
  39 static struct clkdm_ops *arch_clkdm;
  40
  41 /* Private functions */
  42
  43 static struct clockdomain *_clkdm_lookup(const char *name)
  44 {
  45         struct clockdomain *clkdm, *temp_clkdm;
  46
  47         if (!name)
  48                 return NULL;
  49
  50         clkdm = NULL;
  51
  52         list_for_each_entry(temp_clkdm, &clkdm_list, node) {
  53                 if (!strcmp(name, temp_clkdm->name)) {
  54                         clkdm = temp_clkdm;
  55                         break;
  56                 }
  57         }
  58
  59         return clkdm;
  60 }
  61
  62 /**
  63  * _clkdm_register - register a clockdomain
  64  * @clkdm: struct clockdomain * to register
  65  *
  66  * Adds a clockdomain to the internal clockdomain list.
  67  * Returns -EINVAL if given a null pointer, -EEXIST if a clockdomain is
  68  * already registered by the provided name, or 0 upon success.
  69  */
  70 static int _clkdm_register(struct clockdomain *clkdm)
  71 {
  72         struct powerdomain *pwrdm;
  73
  74         if (!clkdm || !clkdm->name)
  75                 return -EINVAL;
  76
  77         pwrdm = pwrdm_lookup(clkdm->pwrdm.name);
  78         if (!pwrdm) {
  79                 pr_err("clockdomain: %s: powerdomain %s does not exist\n",
  80                         clkdm->name, clkdm->pwrdm.name);
  81                 return -EINVAL;
  82         }
  83         clkdm->pwrdm.ptr = pwrdm;
  84
  85         /* Verify that the clockdomain is not already registered */
  86         if (_clkdm_lookup(clkdm->name))
  87                 return -EEXIST;
  88
  89         list_add(&clkdm->node, &clkdm_list);
  90
  91         pwrdm_add_clkdm(pwrdm, clkdm);
  92
  93         spin_lock_init(&clkdm->lock);
  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)
 107                 return ERR_PTR(-EINVAL);
 108
 109         for (cd = deps; cd->clkdm_name; cd++) {
 110                 if (!cd->clkdm && cd->clkdm_name)
 111                         cd->clkdm = _clkdm_lookup(cd->clkdm_name);
 112
 113                 if (cd->clkdm == clkdm)
 114                         break;
 115         }
 116
 117         if (!cd->clkdm_name)
 118                 return ERR_PTR(-ENOENT);
 119
 120         return cd;
 121 }
 122
 123 /*
 124  * _autodep_lookup - resolve autodep clkdm names to clkdm pointers; store
 125  * @autodep: struct clkdm_autodep * to resolve
 126  *
 127  * Resolve autodep clockdomain names to clockdomain pointers via
 128  * clkdm_lookup() and store the pointers in the autodep structure.  An
 129  * "autodep" is a clockdomain sleep/wakeup dependency that is
 130  * automatically added and removed whenever clocks in the associated
 131  * clockdomain are enabled or disabled (respectively) when the
 132  * clockdomain is in hardware-supervised mode.  Meant to be called
 133  * once at clockdomain layer initialization, since these should remain
 134  * fixed for a particular architecture.  No return value.
 135  *
 136  * XXX autodeps are deprecated and should be removed at the earliest
 137  * opportunity
 138  */
 139 static void _autodep_lookup(struct clkdm_autodep *autodep)
 140 {
 141         struct clockdomain *clkdm;
 142
 143         if (!autodep)
 144                 return;
 145
 146         clkdm = clkdm_lookup(autodep->clkdm.name);
 147         if (!clkdm) {
 148                 pr_err("clockdomain: autodeps: clockdomain %s does not exist\n",
 149                          autodep->clkdm.name);
 150                 clkdm = ERR_PTR(-ENOENT);
 151         }
 152         autodep->clkdm.ptr = clkdm;
 153 }
 154
 155 /*
 156  * _clkdm_add_autodeps - add auto sleepdeps/wkdeps to clkdm upon clock enable
 157  * @clkdm: struct clockdomain *
 158  *
 159  * Add the "autodep" sleep & wakeup dependencies to clockdomain 'clkdm'
 160  * in hardware-supervised mode.  Meant to be called from clock framework
 161  * when a clock inside clockdomain 'clkdm' is enabled.  No return value.
 162  *
 163  * XXX autodeps are deprecated and should be removed at the earliest
 164  * opportunity
 165  */
 166 void _clkdm_add_autodeps(struct clockdomain *clkdm)
 167 {
 168         struct clkdm_autodep *autodep;
 169
 170         if (!autodeps || clkdm->flags & CLKDM_NO_AUTODEPS)
 171                 return;
 172
 173         for (autodep = autodeps; autodep->clkdm.ptr; autodep++) {
 174                 if (IS_ERR(autodep->clkdm.ptr))
 175                         continue;
 176
 177                 pr_debug("clockdomain: adding %s sleepdep/wkdep for "
 178                          "clkdm %s\n", autodep->clkdm.ptr->name,
 179                          clkdm->name);
 180
 181                 clkdm_add_sleepdep(clkdm, autodep->clkdm.ptr);
 182                 clkdm_add_wkdep(clkdm, autodep->clkdm.ptr);
 183         }
 184 }
 185
 186 /*
 187  * _clkdm_add_autodeps - remove auto sleepdeps/wkdeps from clkdm
 188  * @clkdm: struct clockdomain *
 189  *
 190  * Remove the "autodep" sleep & wakeup dependencies from clockdomain 'clkdm'
 191  * in hardware-supervised mode.  Meant to be called from clock framework
 192  * when a clock inside clockdomain 'clkdm' is disabled.  No return value.
 193  *
 194  * XXX autodeps are deprecated and should be removed at the earliest
 195  * opportunity
 196  */
 197 void _clkdm_del_autodeps(struct clockdomain *clkdm)
 198 {
 199         struct clkdm_autodep *autodep;
 200
 201         if (!autodeps || clkdm->flags & CLKDM_NO_AUTODEPS)
 202                 return;
 203
 204         for (autodep = autodeps; autodep->clkdm.ptr; autodep++) {
 205                 if (IS_ERR(autodep->clkdm.ptr))
 206                         continue;
 207
 208                 pr_debug("clockdomain: removing %s sleepdep/wkdep for "
 209                          "clkdm %s\n", autodep->clkdm.ptr->name,
 210                          clkdm->name);
 211
 212                 clkdm_del_sleepdep(clkdm, autodep->clkdm.ptr);
 213                 clkdm_del_wkdep(clkdm, autodep->clkdm.ptr);
 214         }
 215 }
 216
 217 /**
 218  * _resolve_clkdm_deps() - resolve clkdm_names in @clkdm_deps to clkdms
 219  * @clkdm: clockdomain that we are resolving dependencies for
 220  * @clkdm_deps: ptr to array of struct clkdm_deps to resolve
 221  *
 222  * Iterates through @clkdm_deps, looking up the struct clockdomain named by
 223  * clkdm_name and storing the clockdomain pointer in the struct clkdm_dep.
 224  * No return value.
 225  */
 226 static void _resolve_clkdm_deps(struct clockdomain *clkdm,
 227                                 struct clkdm_dep *clkdm_deps)
 228 {
 229         struct clkdm_dep *cd;
 230
 231         for (cd = clkdm_deps; cd && cd->clkdm_name; cd++) {
 232                 if (cd->clkdm)
 233                         continue;
 234                 cd->clkdm = _clkdm_lookup(cd->clkdm_name);
 235
 236                 WARN(!cd->clkdm, "clockdomain: %s: could not find clkdm %s while resolving dependencies - should never happen",
 237                      clkdm->name, cd->clkdm_name);
 238         }
 239 }
 240
 241 /* Public functions */
 242
 243 /**
 244  * clkdm_register_platform_funcs - register clockdomain implementation fns
 245  * @co: func pointers for arch specific implementations
 246  *
 247  * Register the list of function pointers used to implement the
 248  * clockdomain functions on different OMAP SoCs.  Should be called
 249  * before any other clkdm_register*() function.  Returns -EINVAL if
 250  * @co is null, -EEXIST if platform functions have already been
 251  * registered, or 0 upon success.
 252  */
 253 int clkdm_register_platform_funcs(struct clkdm_ops *co)
 254 {
 255         if (!co)
 256                 return -EINVAL;
 257
 258         if (arch_clkdm)
 259                 return -EEXIST;
 260
 261         arch_clkdm = co;
 262
 263         return 0;
 264 };
 265
 266 /**
 267  * clkdm_register_clkdms - register SoC clockdomains
 268  * @cs: pointer to an array of struct clockdomain to register
 269  *
 270  * Register the clockdomains available on a particular OMAP SoC.  Must
 271  * be called after clkdm_register_platform_funcs().  May be called
 272  * multiple times.  Returns -EACCES if called before
 273  * clkdm_register_platform_funcs(); -EINVAL if the argument @cs is
 274  * null; or 0 upon success.
 275  */
 276 int clkdm_register_clkdms(struct clockdomain **cs)
 277 {
 278         struct clockdomain **c = NULL;
 279
 280         if (!arch_clkdm)
 281                 return -EACCES;
 282
 283         if (!cs)
 284                 return -EINVAL;
 285
 286         for (c = cs; *c; c++)
 287                 _clkdm_register(*c);
 288
 289         return 0;
 290 }
 291
 292 /**
 293  * clkdm_register_autodeps - register autodeps (if required)
 294  * @ia: pointer to a static array of struct clkdm_autodep to register
 295  *
 296  * Register clockdomain "automatic dependencies."  These are
 297  * clockdomain wakeup and sleep dependencies that are automatically
 298  * added whenever the first clock inside a clockdomain is enabled, and
 299  * removed whenever the last clock inside a clockdomain is disabled.
 300  * These are currently only used on OMAP3 devices, and are deprecated,
 301  * since they waste energy.  However, until the OMAP2/3 IP block
 302  * enable/disable sequence can be converted to match the OMAP4
 303  * sequence, they are needed.
 304  *
 305  * Must be called only after all of the SoC clockdomains are
 306  * registered, since the function will resolve autodep clockdomain
 307  * names into clockdomain pointers.
 308  *
 309  * The struct clkdm_autodep @ia array must be static, as this function
 310  * does not copy the array elements.
 311  *
 312  * Returns -EACCES if called before any clockdomains have been
 313  * registered, -EINVAL if called with a null @ia argument, -EEXIST if
 314  * autodeps have already been registered, or 0 upon success.
 315  */
 316 int clkdm_register_autodeps(struct clkdm_autodep *ia)
 317 {
 318         struct clkdm_autodep *a = NULL;
 319
 320         if (list_empty(&clkdm_list))
 321                 return -EACCES;
 322
 323         if (!ia)
 324                 return -EINVAL;
 325
 326         if (autodeps)
 327                 return -EEXIST;
 328
 329         autodeps = ia;
 330         for (a = autodeps; a->clkdm.ptr; a++)
 331                 _autodep_lookup(a);
 332
 333         return 0;
 334 }
 335
 336 /**
 337  * clkdm_complete_init - set up the clockdomain layer
 338  *
 339  * Put all clockdomains into software-supervised mode; PM code should
 340  * later enable hardware-supervised mode as appropriate.  Must be
 341  * called after clkdm_register_clkdms().  Returns -EACCES if called
 342  * before clkdm_register_clkdms(), or 0 upon success.
 343  */
 344 int clkdm_complete_init(void)
 345 {
 346         struct clockdomain *clkdm;
 347
 348         if (list_empty(&clkdm_list))
 349                 return -EACCES;
 350
 351         list_for_each_entry(clkdm, &clkdm_list, node) {
 352                 if (clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)
 353                         clkdm_wakeup(clkdm);
 354                 else if (clkdm->flags & CLKDM_CAN_DISABLE_AUTO)
 355                         clkdm_deny_idle(clkdm);
 356
 357                 _resolve_clkdm_deps(clkdm, clkdm->wkdep_srcs);
 358                 clkdm_clear_all_wkdeps(clkdm);
 359
 360                 _resolve_clkdm_deps(clkdm, clkdm->sleepdep_srcs);
 361                 clkdm_clear_all_sleepdeps(clkdm);
 362         }
 363
 364         return 0;
 365 }
 366
 367 /**
 368  * clkdm_lookup - look up a clockdomain by name, return a pointer
 369  * @name: name of clockdomain
 370  *
 371  * Find a registered clockdomain by its name @name.  Returns a pointer
 372  * to the struct clockdomain if found, or NULL otherwise.
 373  */
 374 struct clockdomain *clkdm_lookup(const char *name)
 375 {
 376         struct clockdomain *clkdm, *temp_clkdm;
 377
 378         if (!name)
 379                 return NULL;
 380
 381         clkdm = NULL;
 382
 383         list_for_each_entry(temp_clkdm, &clkdm_list, node) {
 384                 if (!strcmp(name, temp_clkdm->name)) {
 385                         clkdm = temp_clkdm;
 386                         break;
 387                 }
 388         }
 389
 390         return clkdm;
 391 }
 392
 393 /**
 394  * clkdm_for_each - call function on each registered clockdomain
 395  * @fn: callback function *
 396  *
 397  * Call the supplied function @fn for each registered clockdomain.
 398  * The callback function @fn can return anything but 0 to bail
 399  * out early from the iterator.  The callback function is called with
 400  * the clkdm_mutex held, so no clockdomain structure manipulation
 401  * functions should be called from the callback, although hardware
 402  * clockdomain control functions are fine.  Returns the last return
 403  * value of the callback function, which should be 0 for success or
 404  * anything else to indicate failure; or -EINVAL if the function pointer
 405  * is null.
 406  */
 407 int clkdm_for_each(int (*fn)(struct clockdomain *clkdm, void *user),
 408                         void *user)
 409 {
 410         struct clockdomain *clkdm;
 411         int ret = 0;
 412
 413         if (!fn)
 414                 return -EINVAL;
 415
 416         list_for_each_entry(clkdm, &clkdm_list, node) {
 417                 ret = (*fn)(clkdm, user);
 418                 if (ret)
 419                         break;
 420         }
 421
 422         return ret;
 423 }
 424
 425
 426 /**
 427  * clkdm_get_pwrdm - return a ptr to the pwrdm that this clkdm resides in
 428  * @clkdm: struct clockdomain *
 429  *
 430  * Return a pointer to the struct powerdomain that the specified clockdomain
 431  * @clkdm exists in, or returns NULL if @clkdm is NULL.
 432  */
 433 struct powerdomain *clkdm_get_pwrdm(struct clockdomain *clkdm)
 434 {
 435         if (!clkdm)
 436                 return NULL;
 437
 438         return clkdm->pwrdm.ptr;
 439 }
 440
 441
 442 /* Hardware clockdomain control */
 443
 444 /**
 445  * clkdm_add_wkdep - add a wakeup dependency from clkdm2 to clkdm1
 446  * @clkdm1: wake this struct clockdomain * up (dependent)
 447  * @clkdm2: when this struct clockdomain * wakes up (source)
 448  *
 449  * When the clockdomain represented by @clkdm2 wakes up, wake up
 450  * @clkdm1. Implemented in hardware on the OMAP, this feature is
 451  * designed to reduce wakeup latency of the dependent clockdomain @clkdm1.
 452  * Returns -EINVAL if presented with invalid clockdomain pointers,
 453  * -ENOENT if @clkdm2 cannot wake up clkdm1 in hardware, or 0 upon
 454  * success.
 455  */
 456 int clkdm_add_wkdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
 457 {
 458         struct clkdm_dep *cd;
 459         int ret = 0;
 460
 461         if (!clkdm1 || !clkdm2)
 462                 return -EINVAL;
 463
 464         cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
 465         if (IS_ERR(cd))
 466                 ret = PTR_ERR(cd);
 467
 468         if (!arch_clkdm || !arch_clkdm->clkdm_add_wkdep)
 469                 ret = -EINVAL;
 470
 471         if (ret) {
 472                 pr_debug("clockdomain: hardware cannot set/clear wake up of "
 473                          "%s when %s wakes up\n", clkdm1->name, clkdm2->name);
 474                 return ret;
 475         }
 476
 477         if (atomic_inc_return(&cd->wkdep_usecount) == 1) {
 478                 pr_debug("clockdomain: hardware will wake up %s when %s wakes "
 479                          "up\n", clkdm1->name, clkdm2->name);
 480
 481                 ret = arch_clkdm->clkdm_add_wkdep(clkdm1, clkdm2);
 482         }
 483
 484         return ret;
 485 }
 486
 487 /**
 488  * clkdm_del_wkdep - remove a wakeup dependency from clkdm2 to clkdm1
 489  * @clkdm1: wake this struct clockdomain * up (dependent)
 490  * @clkdm2: when this struct clockdomain * wakes up (source)
 491  *
 492  * Remove a wakeup dependency causing @clkdm1 to wake up when @clkdm2
 493  * wakes up.  Returns -EINVAL if presented with invalid clockdomain
 494  * pointers, -ENOENT if @clkdm2 cannot wake up clkdm1 in hardware, or
 495  * 0 upon success.
 496  */
 497 int clkdm_del_wkdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
 498 {
 499         struct clkdm_dep *cd;
 500         int ret = 0;
 501
 502         if (!clkdm1 || !clkdm2)
 503                 return -EINVAL;
 504
 505         cd = _clkdm_deps_lookup(clkdm2, clkdm1->wkdep_srcs);
 506         if (IS_ERR(cd))
 507                 ret = PTR_ERR(cd);
 508
 509         if (!arch_clkdm || !arch_clkdm->clkdm_del_wkdep)
 510                 ret = -EINVAL;
 511
 512         if (ret) {
 513                 pr_debug("clockdomain: hardware cannot set/clear wake up of "
 514                          "%s when %s wakes up\n", clkdm1->name, clkdm2->name);
 515                 return ret;
 516         }
 517
 518         if (atomic_dec_return(&cd->wkdep_usecount) == 0) {
 519                 pr_debug("clockdomain: hardware will no longer wake up %s "
 520                          "after %s wakes up\n", clkdm1->name, clkdm2->name);
 521
 522                 ret = arch_clkdm->clkdm_del_wkdep(clkdm1, clkdm2);
 523         }
 524
 525         return ret;
 526 }
 527
 528 /**
 529  * clkdm_read_wkdep - read wakeup dependency state from clkdm2 to clkdm1
 530  * @clkdm1: wake this struct clockdomain * up (dependent)
 531  * @clkdm2: when this struct clockdomain * wakes up (source)
 532  *
 533  * Return 1 if a hardware wakeup dependency exists wherein @clkdm1 will be
 534  * awoken when @clkdm2 wakes up; 0 if dependency is not set; -EINVAL
 535  * if either clockdomain pointer is invalid; or -ENOENT if the hardware
 536  * is incapable.
 537  *
 538  * REVISIT: Currently this function only represents software-controllable
 539  * wakeup dependencies.  Wakeup dependencies fixed in hardware are not
 540  * yet handled here.
 541  */
 542 int clkdm_read_wkdep(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->wkdep_srcs);
 551         if (IS_ERR(cd))
 552                 ret = PTR_ERR(cd);
 553
 554         if (!arch_clkdm || !arch_clkdm->clkdm_read_wkdep)
 555                 ret = -EINVAL;
 556
 557         if (ret) {
 558                 pr_debug("clockdomain: hardware cannot set/clear wake up of "
 559                          "%s when %s wakes up\n", clkdm1->name, clkdm2->name);
 560                 return ret;
 561         }
 562
 563         /* XXX It's faster to return the atomic wkdep_usecount */
 564         return arch_clkdm->clkdm_read_wkdep(clkdm1, clkdm2);
 565 }
 566
 567 /**
 568  * clkdm_clear_all_wkdeps - remove all wakeup dependencies from target clkdm
 569  * @clkdm: struct clockdomain * to remove all wakeup dependencies from
 570  *
 571  * Remove all inter-clockdomain wakeup dependencies that could cause
 572  * @clkdm to wake.  Intended to be used during boot to initialize the
 573  * PRCM to a known state, after all clockdomains are put into swsup idle
 574  * and woken up.  Returns -EINVAL if @clkdm pointer is invalid, or
 575  * 0 upon success.
 576  */
 577 int clkdm_clear_all_wkdeps(struct clockdomain *clkdm)
 578 {
 579         if (!clkdm)
 580                 return -EINVAL;
 581
 582         if (!arch_clkdm || !arch_clkdm->clkdm_clear_all_wkdeps)
 583                 return -EINVAL;
 584
 585         return arch_clkdm->clkdm_clear_all_wkdeps(clkdm);
 586 }
 587
 588 /**
 589  * clkdm_add_sleepdep - add a sleep dependency from clkdm2 to clkdm1
 590  * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
 591  * @clkdm2: when this struct clockdomain * is active (source)
 592  *
 593  * Prevent @clkdm1 from automatically going inactive (and then to
 594  * retention or off) if @clkdm2 is active.  Returns -EINVAL if
 595  * presented with invalid clockdomain pointers or called on a machine
 596  * that does not support software-configurable hardware sleep
 597  * dependencies, -ENOENT if the specified dependency cannot be set in
 598  * hardware, or 0 upon success.
 599  */
 600 int clkdm_add_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
 601 {
 602         struct clkdm_dep *cd;
 603         int ret = 0;
 604
 605         if (!clkdm1 || !clkdm2)
 606                 return -EINVAL;
 607
 608         cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
 609         if (IS_ERR(cd))
 610                 ret = PTR_ERR(cd);
 611
 612         if (!arch_clkdm || !arch_clkdm->clkdm_add_sleepdep)
 613                 ret = -EINVAL;
 614
 615         if (ret) {
 616                 pr_debug("clockdomain: hardware cannot set/clear sleep "
 617                          "dependency affecting %s from %s\n", clkdm1->name,
 618                          clkdm2->name);
 619                 return ret;
 620         }
 621
 622         if (atomic_inc_return(&cd->sleepdep_usecount) == 1) {
 623                 pr_debug("clockdomain: will prevent %s from sleeping if %s "
 624                          "is active\n", clkdm1->name, clkdm2->name);
 625
 626                 ret = arch_clkdm->clkdm_add_sleepdep(clkdm1, clkdm2);
 627         }
 628
 629         return ret;
 630 }
 631
 632 /**
 633  * clkdm_del_sleepdep - remove a sleep dependency from clkdm2 to clkdm1
 634  * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
 635  * @clkdm2: when this struct clockdomain * is active (source)
 636  *
 637  * Allow @clkdm1 to automatically go inactive (and then to retention or
 638  * off), independent of the activity state of @clkdm2.  Returns -EINVAL
 639  * if presented with invalid clockdomain pointers or called on a machine
 640  * that does not support software-configurable hardware sleep dependencies,
 641  * -ENOENT if the specified dependency cannot be cleared in hardware, or
 642  * 0 upon success.
 643  */
 644 int clkdm_del_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
 645 {
 646         struct clkdm_dep *cd;
 647         int ret = 0;
 648
 649         if (!clkdm1 || !clkdm2)
 650                 return -EINVAL;
 651
 652         cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
 653         if (IS_ERR(cd))
 654                 ret = PTR_ERR(cd);
 655
 656         if (!arch_clkdm || !arch_clkdm->clkdm_del_sleepdep)
 657                 ret = -EINVAL;
 658
 659         if (ret) {
 660                 pr_debug("clockdomain: hardware cannot set/clear sleep "
 661                          "dependency affecting %s from %s\n", clkdm1->name,
 662                          clkdm2->name);
 663                 return ret;
 664         }
 665
 666         if (atomic_dec_return(&cd->sleepdep_usecount) == 0) {
 667                 pr_debug("clockdomain: will no longer prevent %s from "
 668                          "sleeping if %s is active\n", clkdm1->name,
 669                          clkdm2->name);
 670
 671                 ret = arch_clkdm->clkdm_del_sleepdep(clkdm1, clkdm2);
 672         }
 673
 674         return ret;
 675 }
 676
 677 /**
 678  * clkdm_read_sleepdep - read sleep dependency state from clkdm2 to clkdm1
 679  * @clkdm1: prevent this struct clockdomain * from sleeping (dependent)
 680  * @clkdm2: when this struct clockdomain * is active (source)
 681  *
 682  * Return 1 if a hardware sleep dependency exists wherein @clkdm1 will
 683  * not be allowed to automatically go inactive if @clkdm2 is active;
 684  * 0 if @clkdm1's automatic power state inactivity transition is independent
 685  * of @clkdm2's; -EINVAL if either clockdomain pointer is invalid or called
 686  * on a machine that does not support software-configurable hardware sleep
 687  * dependencies; or -ENOENT if the hardware is incapable.
 688  *
 689  * REVISIT: Currently this function only represents software-controllable
 690  * sleep dependencies.  Sleep dependencies fixed in hardware are not
 691  * yet handled here.
 692  */
 693 int clkdm_read_sleepdep(struct clockdomain *clkdm1, struct clockdomain *clkdm2)
 694 {
 695         struct clkdm_dep *cd;
 696         int ret = 0;
 697
 698         if (!clkdm1 || !clkdm2)
 699                 return -EINVAL;
 700
 701         cd = _clkdm_deps_lookup(clkdm2, clkdm1->sleepdep_srcs);
 702         if (IS_ERR(cd))
 703                 ret = PTR_ERR(cd);
 704
 705         if (!arch_clkdm || !arch_clkdm->clkdm_read_sleepdep)
 706                 ret = -EINVAL;
 707
 708         if (ret) {
 709                 pr_debug("clockdomain: hardware cannot set/clear sleep "
 710                          "dependency affecting %s from %s\n", clkdm1->name,
 711                          clkdm2->name);
 712                 return ret;
 713         }
 714
 715         /* XXX It's faster to return the atomic sleepdep_usecount */
 716         return arch_clkdm->clkdm_read_sleepdep(clkdm1, clkdm2);
 717 }
 718
 719 /**
 720  * clkdm_clear_all_sleepdeps - remove all sleep dependencies from target clkdm
 721  * @clkdm: struct clockdomain * to remove all sleep dependencies from
 722  *
 723  * Remove all inter-clockdomain sleep dependencies that could prevent
 724  * @clkdm from idling.  Intended to be used during boot to initialize the
 725  * PRCM to a known state, after all clockdomains are put into swsup idle
 726  * and woken up.  Returns -EINVAL if @clkdm pointer is invalid, or
 727  * 0 upon success.
 728  */
 729 int clkdm_clear_all_sleepdeps(struct clockdomain *clkdm)
 730 {
 731         if (!clkdm)
 732                 return -EINVAL;
 733
 734         if (!arch_clkdm || !arch_clkdm->clkdm_clear_all_sleepdeps)
 735                 return -EINVAL;
 736
 737         return arch_clkdm->clkdm_clear_all_sleepdeps(clkdm);
 738 }
 739
 740 /**
 741  * clkdm_sleep - force clockdomain sleep transition
 742  * @clkdm: struct clockdomain *
 743  *
 744  * Instruct the CM to force a sleep transition on the specified
 745  * clockdomain @clkdm.  Returns -EINVAL if @clkdm is NULL or if
 746  * clockdomain does not support software-initiated sleep; 0 upon
 747  * success.
 748  */
 749 int clkdm_sleep(struct clockdomain *clkdm)
 750 {
 751         int ret;
 752         unsigned long flags;
 753
 754         if (!clkdm)
 755                 return -EINVAL;
 756
 757         if (!(clkdm->flags & CLKDM_CAN_FORCE_SLEEP)) {
 758                 pr_debug("clockdomain: %s does not support forcing "
 759                          "sleep via software\n", clkdm->name);
 760                 return -EINVAL;
 761         }
 762
 763         if (!arch_clkdm || !arch_clkdm->clkdm_sleep)
 764                 return -EINVAL;
 765
 766         pr_debug("clockdomain: forcing sleep on %s\n", clkdm->name);
 767
 768         spin_lock_irqsave(&clkdm->lock, flags);
 769         clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
 770         ret = arch_clkdm->clkdm_sleep(clkdm);
 771         spin_unlock_irqrestore(&clkdm->lock, flags);
 772         return ret;
 773 }
 774
 775 /**
 776  * clkdm_wakeup - force clockdomain wakeup transition
 777  * @clkdm: struct clockdomain *
 778  *
 779  * Instruct the CM to force a wakeup transition on the specified
 780  * clockdomain @clkdm.  Returns -EINVAL if @clkdm is NULL or if the
 781  * clockdomain does not support software-controlled wakeup; 0 upon
 782  * success.
 783  */
 784 int clkdm_wakeup(struct clockdomain *clkdm)
 785 {
 786         int ret;
 787         unsigned long flags;
 788
 789         if (!clkdm)
 790                 return -EINVAL;
 791
 792         if (!(clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)) {
 793                 pr_debug("clockdomain: %s does not support forcing "
 794                          "wakeup via software\n", clkdm->name);
 795                 return -EINVAL;
 796         }
 797
 798         if (!arch_clkdm || !arch_clkdm->clkdm_wakeup)
 799                 return -EINVAL;
 800
 801         pr_debug("clockdomain: forcing wakeup on %s\n", clkdm->name);
 802
 803         spin_lock_irqsave(&clkdm->lock, flags);
 804         clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
 805         ret = arch_clkdm->clkdm_wakeup(clkdm);
 806         ret |= pwrdm_state_switch(clkdm->pwrdm.ptr);
 807         spin_unlock_irqrestore(&clkdm->lock, flags);
 808         return ret;
 809 }
 810
 811 /**
 812  * clkdm_allow_idle - enable hwsup idle transitions for clkdm
 813  * @clkdm: struct clockdomain *
 814  *
 815  * Allow the hardware to automatically switch the clockdomain @clkdm into
 816  * active or idle states, as needed by downstream clocks.  If the
 817  * clockdomain has any downstream clocks enabled in the clock
 818  * framework, wkdep/sleepdep autodependencies are added; this is so
 819  * device drivers can read and write to the device.  No return value.
 820  */
 821 void clkdm_allow_idle(struct clockdomain *clkdm)
 822 {
 823         unsigned long flags;
 824
 825         if (!clkdm)
 826                 return;
 827
 828         if (!(clkdm->flags & CLKDM_CAN_ENABLE_AUTO)) {
 829                 pr_debug("clock: automatic idle transitions cannot be enabled "
 830                          "on clockdomain %s\n", clkdm->name);
 831                 return;
 832         }
 833
 834         if (!arch_clkdm || !arch_clkdm->clkdm_allow_idle)
 835                 return;
 836
 837         pr_debug("clockdomain: enabling automatic idle transitions for %s\n",
 838                  clkdm->name);
 839
 840         spin_lock_irqsave(&clkdm->lock, flags);
 841         clkdm->_flags |= _CLKDM_FLAG_HWSUP_ENABLED;
 842         arch_clkdm->clkdm_allow_idle(clkdm);
 843         pwrdm_state_switch(clkdm->pwrdm.ptr);
 844         spin_unlock_irqrestore(&clkdm->lock, flags);
 845 }
 846
 847 /**
 848  * clkdm_deny_idle - disable hwsup idle transitions for clkdm
 849  * @clkdm: struct clockdomain *
 850  *
 851  * Prevent the hardware from automatically switching the clockdomain
 852  * @clkdm into inactive or idle states.  If the clockdomain has
 853  * downstream clocks enabled in the clock framework, wkdep/sleepdep
 854  * autodependencies are removed.  No return value.
 855  */
 856 void clkdm_deny_idle(struct clockdomain *clkdm)
 857 {
 858         unsigned long flags;
 859
 860         if (!clkdm)
 861                 return;
 862
 863         if (!(clkdm->flags & CLKDM_CAN_DISABLE_AUTO)) {
 864                 pr_debug("clockdomain: automatic idle transitions cannot be "
 865                          "disabled on %s\n", clkdm->name);
 866                 return;
 867         }
 868
 869         if (!arch_clkdm || !arch_clkdm->clkdm_deny_idle)
 870                 return;
 871
 872         pr_debug("clockdomain: disabling automatic idle transitions for %s\n",
 873                  clkdm->name);
 874
 875         spin_lock_irqsave(&clkdm->lock, flags);
 876         clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
 877         arch_clkdm->clkdm_deny_idle(clkdm);
 878         pwrdm_state_switch(clkdm->pwrdm.ptr);
 879         spin_unlock_irqrestore(&clkdm->lock, flags);
 880 }
 881
 882 /**
 883  * clkdm_in_hwsup - is clockdomain @clkdm have hardware-supervised idle enabled?
 884  * @clkdm: struct clockdomain *
 885  *
 886  * Returns true if clockdomain @clkdm currently has
 887  * hardware-supervised idle enabled, or false if it does not or if
 888  * @clkdm is NULL.  It is only valid to call this function after
 889  * clkdm_init() has been called.  This function does not actually read
 890  * bits from the hardware; it instead tests an in-memory flag that is
 891  * changed whenever the clockdomain code changes the auto-idle mode.
 892  */
 893 bool clkdm_in_hwsup(struct clockdomain *clkdm)
 894 {
 895         bool ret;
 896         unsigned long flags;
 897
 898         if (!clkdm)
 899                 return false;
 900
 901         spin_lock_irqsave(&clkdm->lock, flags);
 902         ret = (clkdm->_flags & _CLKDM_FLAG_HWSUP_ENABLED) ? true : false;
 903         spin_unlock_irqrestore(&clkdm->lock, flags);
 904
 905         return ret;
 906 }
 907
 908 /* Clockdomain-to-clock/hwmod framework interface code */
 909
 910 static int _clkdm_clk_hwmod_enable(struct clockdomain *clkdm)
 911 {
 912         unsigned long flags;
 913
 914         if (!clkdm || !arch_clkdm || !arch_clkdm->clkdm_clk_enable)
 915                 return -EINVAL;
 916
 917         /*
 918          * For arch's with no autodeps, clkcm_clk_enable
 919          * should be called for every clock instance or hwmod that is
 920          * enabled, so the clkdm can be force woken up.
 921          */
 922         if ((atomic_inc_return(&clkdm->usecount) > 1) && autodeps)
 923                 return 0;
 924
 925         spin_lock_irqsave(&clkdm->lock, flags);
 926         arch_clkdm->clkdm_clk_enable(clkdm);
 927         pwrdm_state_switch(clkdm->pwrdm.ptr);
 928         spin_unlock_irqrestore(&clkdm->lock, flags);
 929
 930         pr_debug("clockdomain: clkdm %s: enabled\n", clkdm->name);
 931
 932         return 0;
 933 }
 934
 935 static int _clkdm_clk_hwmod_disable(struct clockdomain *clkdm)
 936 {
 937         unsigned long flags;
 938
 939         if (!clkdm || !arch_clkdm || !arch_clkdm->clkdm_clk_disable)
 940                 return -EINVAL;
 941
 942         if (atomic_read(&clkdm->usecount) == 0) {
 943                 WARN_ON(1); /* underflow */
 944                 return -ERANGE;
 945         }
 946
 947         if (atomic_dec_return(&clkdm->usecount) > 0)
 948                 return 0;
 949
 950         spin_lock_irqsave(&clkdm->lock, flags);
 951         arch_clkdm->clkdm_clk_disable(clkdm);
 952         pwrdm_state_switch(clkdm->pwrdm.ptr);
 953         spin_unlock_irqrestore(&clkdm->lock, flags);
 954
 955         pr_debug("clockdomain: clkdm %s: disabled\n", clkdm->name);
 956
 957         return 0;
 958 }
 959
 960 /**
 961  * clkdm_clk_enable - add an enabled downstream clock to this clkdm
 962  * @clkdm: struct clockdomain *
 963  * @clk: struct clk * of the enabled downstream clock
 964  *
 965  * Increment the usecount of the clockdomain @clkdm and ensure that it
 966  * is awake before @clk is enabled.  Intended to be called by
 967  * clk_enable() code.  If the clockdomain is in software-supervised
 968  * idle mode, force the clockdomain to wake.  If the clockdomain is in
 969  * hardware-supervised idle mode, add clkdm-pwrdm autodependencies, to
 970  * ensure that devices in the clockdomain can be read from/written to
 971  * by on-chip processors.  Returns -EINVAL if passed null pointers;
 972  * returns 0 upon success or if the clockdomain is in hwsup idle mode.
 973  */
 974 int clkdm_clk_enable(struct clockdomain *clkdm, struct clk *clk)
 975 {
 976         /*
 977          * XXX Rewrite this code to maintain a list of enabled
 978          * downstream clocks for debugging purposes?
 979          */
 980
 981         if (!clk)
 982                 return -EINVAL;
 983
 984         return _clkdm_clk_hwmod_enable(clkdm);
 985 }
 986
 987 /**
 988  * clkdm_clk_disable - remove an enabled downstream clock from this clkdm
 989  * @clkdm: struct clockdomain *
 990  * @clk: struct clk * of the disabled downstream clock
 991  *
 992  * Decrement the usecount of this clockdomain @clkdm when @clk is
 993  * disabled.  Intended to be called by clk_disable() code.  If the
 994  * clockdomain usecount goes to 0, put the clockdomain to sleep
 995  * (software-supervised mode) or remove the clkdm autodependencies
 996  * (hardware-supervised mode).  Returns -EINVAL if passed null
 997  * pointers; -ERANGE if the @clkdm usecount underflows; or returns 0
 998  * upon success or if the clockdomain is in hwsup idle mode.
 999  */
1000 int clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk)
1001 {
1002         /*
1003          * XXX Rewrite this code to maintain a list of enabled
1004          * downstream clocks for debugging purposes?
1005          */
1006
1007         if (!clk)
1008                 return -EINVAL;
1009
1010         return _clkdm_clk_hwmod_disable(clkdm);
1011 }
1012
1013 /**
1014  * clkdm_hwmod_enable - add an enabled downstream hwmod to this clkdm
1015  * @clkdm: struct clockdomain *
1016  * @oh: struct omap_hwmod * of the enabled downstream hwmod
1017  *
1018  * Increment the usecount of the clockdomain @clkdm and ensure that it
1019  * is awake before @oh is enabled. Intended to be called by
1020  * module_enable() code.
1021  * If the clockdomain is in software-supervised idle mode, force the
1022  * clockdomain to wake.  If the clockdomain is in hardware-supervised idle
1023  * mode, add clkdm-pwrdm autodependencies, to ensure that devices in the
1024  * clockdomain can be read from/written to by on-chip processors.
1025  * Returns -EINVAL if passed null pointers;
1026  * returns 0 upon success or if the clockdomain is in hwsup idle mode.
1027  */
1028 int clkdm_hwmod_enable(struct clockdomain *clkdm, struct omap_hwmod *oh)
1029 {
1030         /* The clkdm attribute does not exist yet prior OMAP4 */
1031         if (cpu_is_omap24xx() || cpu_is_omap34xx())
1032                 return 0;
1033
1034         /*
1035          * XXX Rewrite this code to maintain a list of enabled
1036          * downstream hwmods for debugging purposes?
1037          */
1038
1039         if (!oh)
1040                 return -EINVAL;
1041
1042         return _clkdm_clk_hwmod_enable(clkdm);
1043 }
1044
1045 /**
1046  * clkdm_hwmod_disable - remove an enabled downstream hwmod from this clkdm
1047  * @clkdm: struct clockdomain *
1048  * @oh: struct omap_hwmod * of the disabled downstream hwmod
1049  *
1050  * Decrement the usecount of this clockdomain @clkdm when @oh is
1051  * disabled. Intended to be called by module_disable() code.
1052  * If the clockdomain usecount goes to 0, put the clockdomain to sleep
1053  * (software-supervised mode) or remove the clkdm autodependencies
1054  * (hardware-supervised mode).
1055  * Returns -EINVAL if passed null pointers; -ERANGE if the @clkdm usecount
1056  * underflows; or returns 0 upon success or if the clockdomain is in hwsup
1057  * idle mode.
1058  */
1059 int clkdm_hwmod_disable(struct clockdomain *clkdm, struct omap_hwmod *oh)
1060 {
1061         /* The clkdm attribute does not exist yet prior OMAP4 */
1062         if (cpu_is_omap24xx() || cpu_is_omap34xx())
1063                 return 0;
1064
1065         /*
1066          * XXX Rewrite this code to maintain a list of enabled
1067          * downstream hwmods for debugging purposes?
1068          */
1069
1070         if (!oh)
1071                 return -EINVAL;
1072
1073         return _clkdm_clk_hwmod_disable(clkdm);
1074 }
1075