arch/arm/mach-omap2/clockdomain.c

   1 /*
   2  * OMAP2/3 clockdomain framework functions
   3  *
   4  * Copyright (C) 2008 Texas Instruments, Inc.
   5  * Copyright (C) 2008 Nokia Corporation
   6  *
   7  * Written by Paul Walmsley and Jouni Högander
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13 #ifdef CONFIG_OMAP_DEBUG_CLOCKDOMAIN
  14 #  define DEBUG
  15 #endif
  16
  17 #include <linux/module.h>
  18 #include <linux/kernel.h>
  19 #include <linux/device.h>
  20 #include <linux/list.h>
  21 #include <linux/errno.h>
  22 #include <linux/delay.h>
  23 #include <linux/clk.h>
  24 #include <linux/limits.h>
  25 #include <linux/err.h>
  26
  27 #include <linux/io.h>
  28
  29 #include <linux/bitops.h>
  30
  31 #include <mach/clock.h>
  32
  33 #include "prm.h"
  34 #include "prm-regbits-24xx.h"
  35 #include "cm.h"
  36
  37 #include <mach/powerdomain.h>
  38 #include <mach/clockdomain.h>
  39
  40 /* clkdm_list contains all registered struct clockdomains */
  41 static LIST_HEAD(clkdm_list);
  42
  43 /* clkdm_mutex protects clkdm_list add and del ops */
  44 static DEFINE_MUTEX(clkdm_mutex);
  45
  46 /* array of powerdomain deps to be added/removed when clkdm in hwsup mode */
  47 static struct clkdm_pwrdm_autodep *autodeps;
  48
  49
  50 /* Private functions */
  51
  52 /*
  53  * _autodep_lookup - resolve autodep pwrdm names to pwrdm pointers; store
  54  * @autodep: struct clkdm_pwrdm_autodep * to resolve
  55  *
  56  * Resolve autodep powerdomain names to powerdomain pointers via
  57  * pwrdm_lookup() and store the pointers in the autodep structure.  An
  58  * "autodep" is a powerdomain sleep/wakeup dependency that is
  59  * automatically added and removed whenever clocks in the associated
  60  * clockdomain are enabled or disabled (respectively) when the
  61  * clockdomain is in hardware-supervised mode.  Meant to be called
  62  * once at clockdomain layer initialization, since these should remain
  63  * fixed for a particular architecture.  No return value.
  64  */
  65 static void _autodep_lookup(struct clkdm_pwrdm_autodep *autodep)
  66 {
  67         struct powerdomain *pwrdm;
  68
  69         if (!autodep)
  70                 return;
  71
  72         if (!omap_chip_is(autodep->omap_chip))
  73                 return;
  74
  75         pwrdm = pwrdm_lookup(autodep->pwrdm.name);
  76         if (!pwrdm) {
  77                 pr_debug("clockdomain: _autodep_lookup: powerdomain %s "
  78                          "does not exist\n", autodep->pwrdm.name);
  79                 WARN_ON(1);
  80                 pwrdm = ERR_PTR(-ENOENT);
  81         }
  82         autodep->pwrdm.ptr = pwrdm;
  83
  84         return;
  85 }
  86
  87 /*
  88  * _clkdm_add_autodeps - add auto sleepdeps/wkdeps to clkdm upon clock enable
  89  * @clkdm: struct clockdomain *
  90  *
  91  * Add the "autodep" sleep & wakeup dependencies to clockdomain 'clkdm'
  92  * in hardware-supervised mode.  Meant to be called from clock framework
  93  * when a clock inside clockdomain 'clkdm' is enabled.  No return value.
  94  */
  95 static void _clkdm_add_autodeps(struct clockdomain *clkdm)
  96 {
  97         struct clkdm_pwrdm_autodep *autodep;
  98
  99         for (autodep = autodeps; autodep->pwrdm.ptr; autodep++) {
 100                 if (IS_ERR(autodep->pwrdm.ptr))
 101                         continue;
 102
 103                 pr_debug("clockdomain: adding %s sleepdep/wkdep for "
 104                          "pwrdm %s\n", autodep->pwrdm.ptr->name,
 105                          clkdm->pwrdm.ptr->name);
 106
 107                 pwrdm_add_sleepdep(clkdm->pwrdm.ptr, autodep->pwrdm.ptr);
 108                 pwrdm_add_wkdep(clkdm->pwrdm.ptr, autodep->pwrdm.ptr);
 109         }
 110 }
 111
 112 /*
 113  * _clkdm_add_autodeps - remove auto sleepdeps/wkdeps from clkdm
 114  * @clkdm: struct clockdomain *
 115  *
 116  * Remove the "autodep" sleep & wakeup dependencies from clockdomain 'clkdm'
 117  * in hardware-supervised mode.  Meant to be called from clock framework
 118  * when a clock inside clockdomain 'clkdm' is disabled.  No return value.
 119  */
 120 static void _clkdm_del_autodeps(struct clockdomain *clkdm)
 121 {
 122         struct clkdm_pwrdm_autodep *autodep;
 123
 124         for (autodep = autodeps; autodep->pwrdm.ptr; autodep++) {
 125                 if (IS_ERR(autodep->pwrdm.ptr))
 126                         continue;
 127
 128                 pr_debug("clockdomain: removing %s sleepdep/wkdep for "
 129                          "pwrdm %s\n", autodep->pwrdm.ptr->name,
 130                          clkdm->pwrdm.ptr->name);
 131
 132                 pwrdm_del_sleepdep(clkdm->pwrdm.ptr, autodep->pwrdm.ptr);
 133                 pwrdm_del_wkdep(clkdm->pwrdm.ptr, autodep->pwrdm.ptr);
 134         }
 135 }
 136
 137
 138 static struct clockdomain *_clkdm_lookup(const char *name)
 139 {
 140         struct clockdomain *clkdm, *temp_clkdm;
 141
 142         if (!name)
 143                 return NULL;
 144
 145         clkdm = NULL;
 146
 147         list_for_each_entry(temp_clkdm, &clkdm_list, node) {
 148                 if (!strcmp(name, temp_clkdm->name)) {
 149                         clkdm = temp_clkdm;
 150                         break;
 151                 }
 152         }
 153
 154         return clkdm;
 155 }
 156
 157
 158 /* Public functions */
 159
 160 /**
 161  * clkdm_init - set up the clockdomain layer
 162  * @clkdms: optional pointer to an array of clockdomains to register
 163  * @init_autodeps: optional pointer to an array of autodeps to register
 164  *
 165  * Set up internal state.  If a pointer to an array of clockdomains
 166  * was supplied, loop through the list of clockdomains, register all
 167  * that are available on the current platform.  Similarly, if a
 168  * pointer to an array of clockdomain-powerdomain autodependencies was
 169  * provided, register those.  No return value.
 170  */
 171 void clkdm_init(struct clockdomain **clkdms,
 172                 struct clkdm_pwrdm_autodep *init_autodeps)
 173 {
 174         struct clockdomain **c = NULL;
 175         struct clkdm_pwrdm_autodep *autodep = NULL;
 176
 177         if (clkdms)
 178                 for (c = clkdms; *c; c++)
 179                         clkdm_register(*c);
 180
 181         autodeps = init_autodeps;
 182         if (autodeps)
 183                 for (autodep = autodeps; autodep->pwrdm.ptr; autodep++)
 184                         _autodep_lookup(autodep);
 185 }
 186
 187 /**
 188  * clkdm_register - register a clockdomain
 189  * @clkdm: struct clockdomain * to register
 190  *
 191  * Adds a clockdomain to the internal clockdomain list.
 192  * Returns -EINVAL if given a null pointer, -EEXIST if a clockdomain is
 193  * already registered by the provided name, or 0 upon success.
 194  */
 195 int clkdm_register(struct clockdomain *clkdm)
 196 {
 197         int ret = -EINVAL;
 198         struct powerdomain *pwrdm;
 199
 200         if (!clkdm || !clkdm->name)
 201                 return -EINVAL;
 202
 203         if (!omap_chip_is(clkdm->omap_chip))
 204                 return -EINVAL;
 205
 206         pwrdm = pwrdm_lookup(clkdm->pwrdm.name);
 207         if (!pwrdm) {
 208                 pr_debug("clockdomain: clkdm_register %s: powerdomain %s "
 209                          "does not exist\n", clkdm->name, clkdm->pwrdm.name);
 210                 return -EINVAL;
 211         }
 212         clkdm->pwrdm.ptr = pwrdm;
 213
 214         mutex_lock(&clkdm_mutex);
 215         /* Verify that the clockdomain is not already registered */
 216         if (_clkdm_lookup(clkdm->name)) {
 217                 ret = -EEXIST;
 218                 goto cr_unlock;
 219         };
 220
 221         list_add(&clkdm->node, &clkdm_list);
 222
 223         pwrdm_add_clkdm(pwrdm, clkdm);
 224
 225         pr_debug("clockdomain: registered %s\n", clkdm->name);
 226         ret = 0;
 227
 228 cr_unlock:
 229         mutex_unlock(&clkdm_mutex);
 230
 231         return ret;
 232 }
 233
 234 /**
 235  * clkdm_unregister - unregister a clockdomain
 236  * @clkdm: struct clockdomain * to unregister
 237  *
 238  * Removes a clockdomain from the internal clockdomain list.  Returns
 239  * -EINVAL if clkdm argument is NULL.
 240  */
 241 int clkdm_unregister(struct clockdomain *clkdm)
 242 {
 243         if (!clkdm)
 244                 return -EINVAL;
 245
 246         pwrdm_del_clkdm(clkdm->pwrdm.ptr, clkdm);
 247
 248         mutex_lock(&clkdm_mutex);
 249         list_del(&clkdm->node);
 250         mutex_unlock(&clkdm_mutex);
 251
 252         pr_debug("clockdomain: unregistered %s\n", clkdm->name);
 253
 254         return 0;
 255 }
 256
 257 /**
 258  * clkdm_lookup - look up a clockdomain by name, return a pointer
 259  * @name: name of clockdomain
 260  *
 261  * Find a registered clockdomain by its name.  Returns a pointer to the
 262  * struct clockdomain if found, or NULL otherwise.
 263  */
 264 struct clockdomain *clkdm_lookup(const char *name)
 265 {
 266         struct clockdomain *clkdm, *temp_clkdm;
 267
 268         if (!name)
 269                 return NULL;
 270
 271         clkdm = NULL;
 272
 273         mutex_lock(&clkdm_mutex);
 274         list_for_each_entry(temp_clkdm, &clkdm_list, node) {
 275                 if (!strcmp(name, temp_clkdm->name)) {
 276                         clkdm = temp_clkdm;
 277                         break;
 278                 }
 279         }
 280         mutex_unlock(&clkdm_mutex);
 281
 282         return clkdm;
 283 }
 284
 285 /**
 286  * clkdm_for_each - call function on each registered clockdomain
 287  * @fn: callback function *
 288  *
 289  * Call the supplied function for each registered clockdomain.
 290  * The callback function can return anything but 0 to bail
 291  * out early from the iterator.  The callback function is called with
 292  * the clkdm_mutex held, so no clockdomain structure manipulation
 293  * functions should be called from the callback, although hardware
 294  * clockdomain control functions are fine.  Returns the last return
 295  * value of the callback function, which should be 0 for success or
 296  * anything else to indicate failure; or -EINVAL if the function pointer
 297  * is null.
 298  */
 299 int clkdm_for_each(int (*fn)(struct clockdomain *clkdm))
 300 {
 301         struct clockdomain *clkdm;
 302         int ret = 0;
 303
 304         if (!fn)
 305                 return -EINVAL;
 306
 307         mutex_lock(&clkdm_mutex);
 308         list_for_each_entry(clkdm, &clkdm_list, node) {
 309                 ret = (*fn)(clkdm);
 310                 if (ret)
 311                         break;
 312         }
 313         mutex_unlock(&clkdm_mutex);
 314
 315         return ret;
 316 }
 317
 318
 319 /**
 320  * clkdm_get_pwrdm - return a ptr to the pwrdm that this clkdm resides in
 321  * @clkdm: struct clockdomain *
 322  *
 323  * Return a pointer to the struct powerdomain that the specified clockdomain
 324  * 'clkdm' exists in, or returns NULL if clkdm argument is NULL.
 325  */
 326 struct powerdomain *clkdm_get_pwrdm(struct clockdomain *clkdm)
 327 {
 328         if (!clkdm)
 329                 return NULL;
 330
 331         return clkdm->pwrdm.ptr;
 332 }
 333
 334
 335 /* Hardware clockdomain control */
 336
 337 /**
 338  * omap2_clkdm_clktrctrl_read - read the clkdm's current state transition mode
 339  * @clk: struct clk * of a clockdomain
 340  *
 341  * Return the clockdomain's current state transition mode from the
 342  * corresponding domain CM_CLKSTCTRL register.  Returns -EINVAL if clk
 343  * is NULL or the current mode upon success.
 344  */
 345 static int omap2_clkdm_clktrctrl_read(struct clockdomain *clkdm)
 346 {
 347         u32 v;
 348
 349         if (!clkdm)
 350                 return -EINVAL;
 351
 352         v = cm_read_mod_reg(clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL);
 353         v &= clkdm->clktrctrl_mask;
 354         v >>= __ffs(clkdm->clktrctrl_mask);
 355
 356         return v;
 357 }
 358
 359 /**
 360  * omap2_clkdm_sleep - force clockdomain sleep transition
 361  * @clkdm: struct clockdomain *
 362  *
 363  * Instruct the CM to force a sleep transition on the specified
 364  * clockdomain 'clkdm'.  Returns -EINVAL if clk is NULL or if
 365  * clockdomain does not support software-initiated sleep; 0 upon
 366  * success.
 367  */
 368 int omap2_clkdm_sleep(struct clockdomain *clkdm)
 369 {
 370         if (!clkdm)
 371                 return -EINVAL;
 372
 373         if (!(clkdm->flags & CLKDM_CAN_FORCE_SLEEP)) {
 374                 pr_debug("clockdomain: %s does not support forcing "
 375                          "sleep via software\n", clkdm->name);
 376                 return -EINVAL;
 377         }
 378
 379         pr_debug("clockdomain: forcing sleep on %s\n", clkdm->name);
 380
 381         if (cpu_is_omap24xx()) {
 382
 383                 cm_set_mod_reg_bits(OMAP24XX_FORCESTATE,
 384                                     clkdm->pwrdm.ptr->prcm_offs, PM_PWSTCTRL);
 385
 386         } else if (cpu_is_omap34xx()) {
 387
 388                 u32 v = (OMAP34XX_CLKSTCTRL_FORCE_SLEEP <<
 389                          __ffs(clkdm->clktrctrl_mask));
 390
 391                 cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, v,
 392                                     clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL);
 393
 394         } else {
 395                 BUG();
 396         };
 397
 398         return 0;
 399 }
 400
 401 /**
 402  * omap2_clkdm_wakeup - force clockdomain wakeup transition
 403  * @clkdm: struct clockdomain *
 404  *
 405  * Instruct the CM to force a wakeup transition on the specified
 406  * clockdomain 'clkdm'.  Returns -EINVAL if clkdm is NULL or if the
 407  * clockdomain does not support software-controlled wakeup; 0 upon
 408  * success.
 409  */
 410 int omap2_clkdm_wakeup(struct clockdomain *clkdm)
 411 {
 412         if (!clkdm)
 413                 return -EINVAL;
 414
 415         if (!(clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)) {
 416                 pr_debug("clockdomain: %s does not support forcing "
 417                          "wakeup via software\n", clkdm->name);
 418                 return -EINVAL;
 419         }
 420
 421         pr_debug("clockdomain: forcing wakeup on %s\n", clkdm->name);
 422
 423         if (cpu_is_omap24xx()) {
 424
 425                 cm_clear_mod_reg_bits(OMAP24XX_FORCESTATE,
 426                                       clkdm->pwrdm.ptr->prcm_offs, PM_PWSTCTRL);
 427
 428         } else if (cpu_is_omap34xx()) {
 429
 430                 u32 v = (OMAP34XX_CLKSTCTRL_FORCE_WAKEUP <<
 431                          __ffs(clkdm->clktrctrl_mask));
 432
 433                 cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, v,
 434                                     clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL);
 435
 436         } else {
 437                 BUG();
 438         };
 439
 440         return 0;
 441 }
 442
 443 /**
 444  * omap2_clkdm_allow_idle - enable hwsup idle transitions for clkdm
 445  * @clkdm: struct clockdomain *
 446  *
 447  * Allow the hardware to automatically switch the clockdomain into
 448  * active or idle states, as needed by downstream clocks.  If the
 449  * clockdomain has any downstream clocks enabled in the clock
 450  * framework, wkdep/sleepdep autodependencies are added; this is so
 451  * device drivers can read and write to the device.  No return value.
 452  */
 453 void omap2_clkdm_allow_idle(struct clockdomain *clkdm)
 454 {
 455         u32 v;
 456
 457         if (!clkdm)
 458                 return;
 459
 460         if (!(clkdm->flags & CLKDM_CAN_ENABLE_AUTO)) {
 461                 pr_debug("clock: automatic idle transitions cannot be enabled "
 462                          "on clockdomain %s\n", clkdm->name);
 463                 return;
 464         }
 465
 466         pr_debug("clockdomain: enabling automatic idle transitions for %s\n",
 467                  clkdm->name);
 468
 469         if (atomic_read(&clkdm->usecount) > 0)
 470                 _clkdm_add_autodeps(clkdm);
 471
 472         if (cpu_is_omap24xx())
 473                 v = OMAP24XX_CLKSTCTRL_ENABLE_AUTO;
 474         else if (cpu_is_omap34xx())
 475                 v = OMAP34XX_CLKSTCTRL_ENABLE_AUTO;
 476         else
 477                 BUG();
 478
 479
 480         cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask,
 481                             v << __ffs(clkdm->clktrctrl_mask),
 482                             clkdm->pwrdm.ptr->prcm_offs,
 483                             CM_CLKSTCTRL);
 484 }
 485
 486 /**
 487  * omap2_clkdm_deny_idle - disable hwsup idle transitions for clkdm
 488  * @clkdm: struct clockdomain *
 489  *
 490  * Prevent the hardware from automatically switching the clockdomain
 491  * into inactive or idle states.  If the clockdomain has downstream
 492  * clocks enabled in the clock framework, wkdep/sleepdep
 493  * autodependencies are removed.  No return value.
 494  */
 495 void omap2_clkdm_deny_idle(struct clockdomain *clkdm)
 496 {
 497         u32 v;
 498
 499         if (!clkdm)
 500                 return;
 501
 502         if (!(clkdm->flags & CLKDM_CAN_DISABLE_AUTO)) {
 503                 pr_debug("clockdomain: automatic idle transitions cannot be "
 504                          "disabled on %s\n", clkdm->name);
 505                 return;
 506         }
 507
 508         pr_debug("clockdomain: disabling automatic idle transitions for %s\n",
 509                  clkdm->name);
 510
 511         if (cpu_is_omap24xx())
 512                 v = OMAP24XX_CLKSTCTRL_DISABLE_AUTO;
 513         else if (cpu_is_omap34xx())
 514                 v = OMAP34XX_CLKSTCTRL_DISABLE_AUTO;
 515         else
 516                 BUG();
 517
 518         cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask,
 519                             v << __ffs(clkdm->clktrctrl_mask),
 520                             clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL);
 521
 522         if (atomic_read(&clkdm->usecount) > 0)
 523                 _clkdm_del_autodeps(clkdm);
 524 }
 525
 526
 527 /* Clockdomain-to-clock framework interface code */
 528
 529 /**
 530  * omap2_clkdm_clk_enable - add an enabled downstream clock to this clkdm
 531  * @clkdm: struct clockdomain *
 532  * @clk: struct clk * of the enabled downstream clock
 533  *
 534  * Increment the usecount of this clockdomain 'clkdm' and ensure that
 535  * it is awake.  Intended to be called by clk_enable() code.  If the
 536  * clockdomain is in software-supervised idle mode, force the
 537  * clockdomain to wake.  If the clockdomain is in hardware-supervised
 538  * idle mode, add clkdm-pwrdm autodependencies, to ensure that devices
 539  * in the clockdomain can be read from/written to by on-chip processors.
 540  * Returns -EINVAL if passed null pointers; returns 0 upon success or
 541  * if the clockdomain is in hwsup idle mode.
 542  */
 543 int omap2_clkdm_clk_enable(struct clockdomain *clkdm, struct clk *clk)
 544 {
 545         int v;
 546
 547         /*
 548          * XXX Rewrite this code to maintain a list of enabled
 549          * downstream clocks for debugging purposes?
 550          */
 551
 552         if (!clkdm || !clk)
 553                 return -EINVAL;
 554
 555         if (atomic_inc_return(&clkdm->usecount) > 1)
 556                 return 0;
 557
 558         /* Clockdomain now has one enabled downstream clock */
 559
 560         pr_debug("clockdomain: clkdm %s: clk %s now enabled\n", clkdm->name,
 561                  clk->name);
 562
 563         v = omap2_clkdm_clktrctrl_read(clkdm);
 564
 565         if ((cpu_is_omap34xx() && v == OMAP34XX_CLKSTCTRL_ENABLE_AUTO) ||
 566             (cpu_is_omap24xx() && v == OMAP24XX_CLKSTCTRL_ENABLE_AUTO))
 567                 _clkdm_add_autodeps(clkdm);
 568         else
 569                 omap2_clkdm_wakeup(clkdm);
 570
 571         pwrdm_wait_transition(clkdm->pwrdm.ptr);
 572
 573         return 0;
 574 }
 575
 576 /**
 577  * omap2_clkdm_clk_disable - remove an enabled downstream clock from this clkdm
 578  * @clkdm: struct clockdomain *
 579  * @clk: struct clk * of the disabled downstream clock
 580  *
 581  * Decrement the usecount of this clockdomain 'clkdm'. Intended to be
 582  * called by clk_disable() code.  If the usecount goes to 0, put the
 583  * clockdomain to sleep (software-supervised mode) or remove the
 584  * clkdm-pwrdm autodependencies (hardware-supervised mode).  Returns
 585  * -EINVAL if passed null pointers; -ERANGE if the clkdm usecount
 586  * underflows and debugging is enabled; or returns 0 upon success or
 587  * if the clockdomain is in hwsup idle mode.
 588  */
 589 int omap2_clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk)
 590 {
 591         int v;
 592
 593         /*
 594          * XXX Rewrite this code to maintain a list of enabled
 595          * downstream clocks for debugging purposes?
 596          */
 597
 598         if (!clkdm || !clk)
 599                 return -EINVAL;
 600
 601 #ifdef DEBUG
 602         if (atomic_read(&clkdm->usecount) == 0) {
 603                 WARN_ON(1); /* underflow */
 604                 return -ERANGE;
 605         }
 606 #endif
 607
 608         if (atomic_dec_return(&clkdm->usecount) > 0)
 609                 return 0;
 610
 611         /* All downstream clocks of this clockdomain are now disabled */
 612
 613         pr_debug("clockdomain: clkdm %s: clk %s now disabled\n", clkdm->name,
 614                  clk->name);
 615
 616         v = omap2_clkdm_clktrctrl_read(clkdm);
 617
 618         if ((cpu_is_omap34xx() && v == OMAP34XX_CLKSTCTRL_ENABLE_AUTO) ||
 619             (cpu_is_omap24xx() && v == OMAP24XX_CLKSTCTRL_ENABLE_AUTO))
 620                 _clkdm_del_autodeps(clkdm);
 621         else
 622                 omap2_clkdm_sleep(clkdm);
 623
 624         return 0;
 625 }
 626