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