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                 if (!omap_chip_is(autodep->omap_chip))
 104                         continue;
 105
 106                 pr_debug("clockdomain: adding %s sleepdep/wkdep for "
 107                          "pwrdm %s\n", autodep->pwrdm.ptr->name,
 108                          clkdm->pwrdm.ptr->name);
 109
 110                 pwrdm_add_sleepdep(clkdm->pwrdm.ptr, autodep->pwrdm.ptr);
 111                 pwrdm_add_wkdep(clkdm->pwrdm.ptr, autodep->pwrdm.ptr);
 112         }
 113 }
 114
 115 /*
 116  * _clkdm_add_autodeps - remove auto sleepdeps/wkdeps from clkdm
 117  * @clkdm: struct clockdomain *
 118  *
 119  * Remove the "autodep" sleep & wakeup dependencies from clockdomain 'clkdm'
 120  * in hardware-supervised mode.  Meant to be called from clock framework
 121  * when a clock inside clockdomain 'clkdm' is disabled.  No return value.
 122  */
 123 static void _clkdm_del_autodeps(struct clockdomain *clkdm)
 124 {
 125         struct clkdm_pwrdm_autodep *autodep;
 126
 127         for (autodep = autodeps; autodep->pwrdm.ptr; autodep++) {
 128                 if (IS_ERR(autodep->pwrdm.ptr))
 129                         continue;
 130
 131                 if (!omap_chip_is(autodep->omap_chip))
 132                         continue;
 133
 134                 pr_debug("clockdomain: removing %s sleepdep/wkdep for "
 135                          "pwrdm %s\n", autodep->pwrdm.ptr->name,
 136                          clkdm->pwrdm.ptr->name);
 137
 138                 pwrdm_del_sleepdep(clkdm->pwrdm.ptr, autodep->pwrdm.ptr);
 139                 pwrdm_del_wkdep(clkdm->pwrdm.ptr, autodep->pwrdm.ptr);
 140         }
 141 }
 142
 143
 144 static struct clockdomain *_clkdm_lookup(const char *name)
 145 {
 146         struct clockdomain *clkdm, *temp_clkdm;
 147
 148         if (!name)
 149                 return NULL;
 150
 151         clkdm = NULL;
 152
 153         list_for_each_entry(temp_clkdm, &clkdm_list, node) {
 154                 if (!strcmp(name, temp_clkdm->name)) {
 155                         clkdm = temp_clkdm;
 156                         break;
 157                 }
 158         }
 159
 160         return clkdm;
 161 }
 162
 163
 164 /* Public functions */
 165
 166 /**
 167  * clkdm_init - set up the clockdomain layer
 168  * @clkdms: optional pointer to an array of clockdomains to register
 169  * @init_autodeps: optional pointer to an array of autodeps to register
 170  *
 171  * Set up internal state.  If a pointer to an array of clockdomains
 172  * was supplied, loop through the list of clockdomains, register all
 173  * that are available on the current platform.  Similarly, if a
 174  * pointer to an array of clockdomain-powerdomain autodependencies was
 175  * provided, register those.  No return value.
 176  */
 177 void clkdm_init(struct clockdomain **clkdms,
 178                 struct clkdm_pwrdm_autodep *init_autodeps)
 179 {
 180         struct clockdomain **c = NULL;
 181         struct clkdm_pwrdm_autodep *autodep = NULL;
 182
 183         if (clkdms)
 184                 for (c = clkdms; *c; c++)
 185                         clkdm_register(*c);
 186
 187         autodeps = init_autodeps;
 188         if (autodeps)
 189                 for (autodep = autodeps; autodep->pwrdm.ptr; autodep++)
 190                         _autodep_lookup(autodep);
 191 }
 192
 193 /**
 194  * clkdm_register - register a clockdomain
 195  * @clkdm: struct clockdomain * to register
 196  *
 197  * Adds a clockdomain to the internal clockdomain list.
 198  * Returns -EINVAL if given a null pointer, -EEXIST if a clockdomain is
 199  * already registered by the provided name, or 0 upon success.
 200  */
 201 int clkdm_register(struct clockdomain *clkdm)
 202 {
 203         int ret = -EINVAL;
 204         struct powerdomain *pwrdm;
 205
 206         if (!clkdm || !clkdm->name)
 207                 return -EINVAL;
 208
 209         if (!omap_chip_is(clkdm->omap_chip))
 210                 return -EINVAL;
 211
 212         pwrdm = pwrdm_lookup(clkdm->pwrdm.name);
 213         if (!pwrdm) {
 214                 pr_debug("clockdomain: clkdm_register %s: powerdomain %s "
 215                          "does not exist\n", clkdm->name, clkdm->pwrdm.name);
 216                 return -EINVAL;
 217         }
 218         clkdm->pwrdm.ptr = pwrdm;
 219
 220         mutex_lock(&clkdm_mutex);
 221         /* Verify that the clockdomain is not already registered */
 222         if (_clkdm_lookup(clkdm->name)) {
 223                 ret = -EEXIST;
 224                 goto cr_unlock;
 225         };
 226
 227         list_add(&clkdm->node, &clkdm_list);
 228
 229         pwrdm_add_clkdm(pwrdm, clkdm);
 230
 231         pr_debug("clockdomain: registered %s\n", clkdm->name);
 232         ret = 0;
 233
 234 cr_unlock:
 235         mutex_unlock(&clkdm_mutex);
 236
 237         return ret;
 238 }
 239
 240 /**
 241  * clkdm_unregister - unregister a clockdomain
 242  * @clkdm: struct clockdomain * to unregister
 243  *
 244  * Removes a clockdomain from the internal clockdomain list.  Returns
 245  * -EINVAL if clkdm argument is NULL.
 246  */
 247 int clkdm_unregister(struct clockdomain *clkdm)
 248 {
 249         if (!clkdm)
 250                 return -EINVAL;
 251
 252         pwrdm_del_clkdm(clkdm->pwrdm.ptr, clkdm);
 253
 254         mutex_lock(&clkdm_mutex);
 255         list_del(&clkdm->node);
 256         mutex_unlock(&clkdm_mutex);
 257
 258         pr_debug("clockdomain: unregistered %s\n", clkdm->name);
 259
 260         return 0;
 261 }
 262
 263 /**
 264  * clkdm_lookup - look up a clockdomain by name, return a pointer
 265  * @name: name of clockdomain
 266  *
 267  * Find a registered clockdomain by its name.  Returns a pointer to the
 268  * struct clockdomain if found, or NULL otherwise.
 269  */
 270 struct clockdomain *clkdm_lookup(const char *name)
 271 {
 272         struct clockdomain *clkdm, *temp_clkdm;
 273
 274         if (!name)
 275                 return NULL;
 276
 277         clkdm = NULL;
 278
 279         mutex_lock(&clkdm_mutex);
 280         list_for_each_entry(temp_clkdm, &clkdm_list, node) {
 281                 if (!strcmp(name, temp_clkdm->name)) {
 282                         clkdm = temp_clkdm;
 283                         break;
 284                 }
 285         }
 286         mutex_unlock(&clkdm_mutex);
 287
 288         return clkdm;
 289 }
 290
 291 /**
 292  * clkdm_for_each - call function on each registered clockdomain
 293  * @fn: callback function *
 294  *
 295  * Call the supplied function for each registered clockdomain.
 296  * The callback function can return anything but 0 to bail
 297  * out early from the iterator.  The callback function is called with
 298  * the clkdm_mutex held, so no clockdomain structure manipulation
 299  * functions should be called from the callback, although hardware
 300  * clockdomain control functions are fine.  Returns the last return
 301  * value of the callback function, which should be 0 for success or
 302  * anything else to indicate failure; or -EINVAL if the function pointer
 303  * is null.
 304  */
 305 int clkdm_for_each(int (*fn)(struct clockdomain *clkdm))
 306 {
 307         struct clockdomain *clkdm;
 308         int ret = 0;
 309
 310         if (!fn)
 311                 return -EINVAL;
 312
 313         mutex_lock(&clkdm_mutex);
 314         list_for_each_entry(clkdm, &clkdm_list, node) {
 315                 ret = (*fn)(clkdm);
 316                 if (ret)
 317                         break;
 318         }
 319         mutex_unlock(&clkdm_mutex);
 320
 321         return ret;
 322 }
 323
 324
 325 /**
 326  * clkdm_get_pwrdm - return a ptr to the pwrdm that this clkdm resides in
 327  * @clkdm: struct clockdomain *
 328  *
 329  * Return a pointer to the struct powerdomain that the specified clockdomain
 330  * 'clkdm' exists in, or returns NULL if clkdm argument is NULL.
 331  */
 332 struct powerdomain *clkdm_get_pwrdm(struct clockdomain *clkdm)
 333 {
 334         if (!clkdm)
 335                 return NULL;
 336
 337         return clkdm->pwrdm.ptr;
 338 }
 339
 340
 341 /* Hardware clockdomain control */
 342
 343 /**
 344  * omap2_clkdm_clktrctrl_read - read the clkdm's current state transition mode
 345  * @clk: struct clk * of a clockdomain
 346  *
 347  * Return the clockdomain's current state transition mode from the
 348  * corresponding domain CM_CLKSTCTRL register.  Returns -EINVAL if clk
 349  * is NULL or the current mode upon success.
 350  */
 351 static int omap2_clkdm_clktrctrl_read(struct clockdomain *clkdm)
 352 {
 353         u32 v;
 354
 355         if (!clkdm)
 356                 return -EINVAL;
 357
 358         v = cm_read_mod_reg(clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL);
 359         v &= clkdm->clktrctrl_mask;
 360         v >>= __ffs(clkdm->clktrctrl_mask);
 361
 362         return v;
 363 }
 364
 365 /**
 366  * omap2_clkdm_sleep - force clockdomain sleep transition
 367  * @clkdm: struct clockdomain *
 368  *
 369  * Instruct the CM to force a sleep transition on the specified
 370  * clockdomain 'clkdm'.  Returns -EINVAL if clk is NULL or if
 371  * clockdomain does not support software-initiated sleep; 0 upon
 372  * success.
 373  */
 374 int omap2_clkdm_sleep(struct clockdomain *clkdm)
 375 {
 376         if (!clkdm)
 377                 return -EINVAL;
 378
 379         if (!(clkdm->flags & CLKDM_CAN_FORCE_SLEEP)) {
 380                 pr_debug("clockdomain: %s does not support forcing "
 381                          "sleep via software\n", clkdm->name);
 382                 return -EINVAL;
 383         }
 384
 385         pr_debug("clockdomain: forcing sleep on %s\n", clkdm->name);
 386
 387         if (cpu_is_omap24xx()) {
 388
 389                 cm_set_mod_reg_bits(OMAP24XX_FORCESTATE,
 390                                     clkdm->pwrdm.ptr->prcm_offs, PM_PWSTCTRL);
 391
 392         } else if (cpu_is_omap34xx()) {
 393
 394                 u32 v = (OMAP34XX_CLKSTCTRL_FORCE_SLEEP <<
 395                          __ffs(clkdm->clktrctrl_mask));
 396
 397                 cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, v,
 398                                     clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL);
 399
 400         } else {
 401                 BUG();
 402         };
 403
 404         return 0;
 405 }
 406
 407 /**
 408  * omap2_clkdm_wakeup - force clockdomain wakeup transition
 409  * @clkdm: struct clockdomain *
 410  *
 411  * Instruct the CM to force a wakeup transition on the specified
 412  * clockdomain 'clkdm'.  Returns -EINVAL if clkdm is NULL or if the
 413  * clockdomain does not support software-controlled wakeup; 0 upon
 414  * success.
 415  */
 416 int omap2_clkdm_wakeup(struct clockdomain *clkdm)
 417 {
 418         if (!clkdm)
 419                 return -EINVAL;
 420
 421         if (!(clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)) {
 422                 pr_debug("clockdomain: %s does not support forcing "
 423                          "wakeup via software\n", clkdm->name);
 424                 return -EINVAL;
 425         }
 426
 427         pr_debug("clockdomain: forcing wakeup on %s\n", clkdm->name);
 428
 429         if (cpu_is_omap24xx()) {
 430
 431                 cm_clear_mod_reg_bits(OMAP24XX_FORCESTATE,
 432                                       clkdm->pwrdm.ptr->prcm_offs, PM_PWSTCTRL);
 433
 434         } else if (cpu_is_omap34xx()) {
 435
 436                 u32 v = (OMAP34XX_CLKSTCTRL_FORCE_WAKEUP <<
 437                          __ffs(clkdm->clktrctrl_mask));
 438
 439                 cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, v,
 440                                     clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL);
 441
 442         } else {
 443                 BUG();
 444         };
 445
 446         return 0;
 447 }
 448
 449 /**
 450  * omap2_clkdm_allow_idle - enable hwsup idle transitions for clkdm
 451  * @clkdm: struct clockdomain *
 452  *
 453  * Allow the hardware to automatically switch the clockdomain into
 454  * active or idle states, as needed by downstream clocks.  If the
 455  * clockdomain has any downstream clocks enabled in the clock
 456  * framework, wkdep/sleepdep autodependencies are added; this is so
 457  * device drivers can read and write to the device.  No return value.
 458  */
 459 void omap2_clkdm_allow_idle(struct clockdomain *clkdm)
 460 {
 461         u32 v;
 462
 463         if (!clkdm)
 464                 return;
 465
 466         if (!(clkdm->flags & CLKDM_CAN_ENABLE_AUTO)) {
 467                 pr_debug("clock: automatic idle transitions cannot be enabled "
 468                          "on clockdomain %s\n", clkdm->name);
 469                 return;
 470         }
 471
 472         pr_debug("clockdomain: enabling automatic idle transitions for %s\n",
 473                  clkdm->name);
 474
 475         if (atomic_read(&clkdm->usecount) > 0)
 476                 _clkdm_add_autodeps(clkdm);
 477
 478         if (cpu_is_omap24xx())
 479                 v = OMAP24XX_CLKSTCTRL_ENABLE_AUTO;
 480         else if (cpu_is_omap34xx())
 481                 v = OMAP34XX_CLKSTCTRL_ENABLE_AUTO;
 482         else
 483                 BUG();
 484
 485
 486         cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask,
 487                             v << __ffs(clkdm->clktrctrl_mask),
 488                             clkdm->pwrdm.ptr->prcm_offs,
 489                             CM_CLKSTCTRL);
 490 }
 491
 492 /**
 493  * omap2_clkdm_deny_idle - disable hwsup idle transitions for clkdm
 494  * @clkdm: struct clockdomain *
 495  *
 496  * Prevent the hardware from automatically switching the clockdomain
 497  * into inactive or idle states.  If the clockdomain has downstream
 498  * clocks enabled in the clock framework, wkdep/sleepdep
 499  * autodependencies are removed.  No return value.
 500  */
 501 void omap2_clkdm_deny_idle(struct clockdomain *clkdm)
 502 {
 503         u32 v;
 504
 505         if (!clkdm)
 506                 return;
 507
 508         if (!(clkdm->flags & CLKDM_CAN_DISABLE_AUTO)) {
 509                 pr_debug("clockdomain: automatic idle transitions cannot be "
 510                          "disabled on %s\n", clkdm->name);
 511                 return;
 512         }
 513
 514         pr_debug("clockdomain: disabling automatic idle transitions for %s\n",
 515                  clkdm->name);
 516
 517         if (cpu_is_omap24xx())
 518                 v = OMAP24XX_CLKSTCTRL_DISABLE_AUTO;
 519         else if (cpu_is_omap34xx())
 520                 v = OMAP34XX_CLKSTCTRL_DISABLE_AUTO;
 521         else
 522                 BUG();
 523
 524         cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask,
 525                             v << __ffs(clkdm->clktrctrl_mask),
 526                             clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL);
 527
 528         if (atomic_read(&clkdm->usecount) > 0)
 529                 _clkdm_del_autodeps(clkdm);
 530 }
 531
 532
 533 /* Clockdomain-to-clock framework interface code */
 534
 535 /**
 536  * omap2_clkdm_clk_enable - add an enabled downstream clock to this clkdm
 537  * @clkdm: struct clockdomain *
 538  * @clk: struct clk * of the enabled downstream clock
 539  *
 540  * Increment the usecount of this clockdomain 'clkdm' and ensure that
 541  * it is awake.  Intended to be called by clk_enable() code.  If the
 542  * clockdomain is in software-supervised idle mode, force the
 543  * clockdomain to wake.  If the clockdomain is in hardware-supervised
 544  * idle mode, add clkdm-pwrdm autodependencies, to ensure that devices
 545  * in the clockdomain can be read from/written to by on-chip processors.
 546  * Returns -EINVAL if passed null pointers; returns 0 upon success or
 547  * if the clockdomain is in hwsup idle mode.
 548  */
 549 int omap2_clkdm_clk_enable(struct clockdomain *clkdm, struct clk *clk)
 550 {
 551         int v;
 552
 553         /*
 554          * XXX Rewrite this code to maintain a list of enabled
 555          * downstream clocks for debugging purposes?
 556          */
 557
 558         if (!clkdm || !clk)
 559                 return -EINVAL;
 560
 561         if (atomic_inc_return(&clkdm->usecount) > 1)
 562                 return 0;
 563
 564         /* Clockdomain now has one enabled downstream clock */
 565
 566         pr_debug("clockdomain: clkdm %s: clk %s now enabled\n", clkdm->name,
 567                  clk->name);
 568
 569         v = omap2_clkdm_clktrctrl_read(clkdm);
 570
 571         if ((cpu_is_omap34xx() && v == OMAP34XX_CLKSTCTRL_ENABLE_AUTO) ||
 572             (cpu_is_omap24xx() && v == OMAP24XX_CLKSTCTRL_ENABLE_AUTO))
 573                 _clkdm_add_autodeps(clkdm);
 574         else
 575                 omap2_clkdm_wakeup(clkdm);
 576
 577         pwrdm_wait_transition(clkdm->pwrdm.ptr);
 578
 579         return 0;
 580 }
 581
 582 /**
 583  * omap2_clkdm_clk_disable - remove an enabled downstream clock from this clkdm
 584  * @clkdm: struct clockdomain *
 585  * @clk: struct clk * of the disabled downstream clock
 586  *
 587  * Decrement the usecount of this clockdomain 'clkdm'. Intended to be
 588  * called by clk_disable() code.  If the usecount goes to 0, put the
 589  * clockdomain to sleep (software-supervised mode) or remove the
 590  * clkdm-pwrdm autodependencies (hardware-supervised mode).  Returns
 591  * -EINVAL if passed null pointers; -ERANGE if the clkdm usecount
 592  * underflows and debugging is enabled; or returns 0 upon success or
 593  * if the clockdomain is in hwsup idle mode.
 594  */
 595 int omap2_clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk)
 596 {
 597         int v;
 598
 599         /*
 600          * XXX Rewrite this code to maintain a list of enabled
 601          * downstream clocks for debugging purposes?
 602          */
 603
 604         if (!clkdm || !clk)
 605                 return -EINVAL;
 606
 607 #ifdef DEBUG
 608         if (atomic_read(&clkdm->usecount) == 0) {
 609                 WARN_ON(1); /* underflow */
 610                 return -ERANGE;
 611         }
 612 #endif
 613
 614         if (atomic_dec_return(&clkdm->usecount) > 0)
 615                 return 0;
 616
 617         /* All downstream clocks of this clockdomain are now disabled */
 618
 619         pr_debug("clockdomain: clkdm %s: clk %s now disabled\n", clkdm->name,
 620                  clk->name);
 621
 622         v = omap2_clkdm_clktrctrl_read(clkdm);
 623
 624         if ((cpu_is_omap34xx() && v == OMAP34XX_CLKSTCTRL_ENABLE_AUTO) ||
 625             (cpu_is_omap24xx() && v == OMAP24XX_CLKSTCTRL_ENABLE_AUTO))
 626                 _clkdm_del_autodeps(clkdm);
 627         else
 628                 omap2_clkdm_sleep(clkdm);
 629
 630         return 0;
 631 }
 632