arch/arm/plat-omap/clock.c

   1 /*
   2  *  linux/arch/arm/plat-omap/clock.c
   3  *
   4  *  Copyright (C) 2004 - 2008 Nokia corporation
   5  *  Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
   6  *
   7  *  Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
   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 #include <linux/kernel.h>
  14 #include <linux/init.h>
  15 #include <linux/module.h>
  16 #include <linux/list.h>
  17 #include <linux/errno.h>
  18 #include <linux/err.h>
  19 #include <linux/string.h>
  20 #include <linux/clk.h>
  21 #include <linux/mutex.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/cpufreq.h>
  24 #include <linux/debugfs.h>
  25 #include <linux/io.h>
  26 #include <linux/bootmem.h>
  27 #include <linux/slab.h>
  28
  29 #include <mach/clock.h>
  30
  31 static LIST_HEAD(clocks);
  32 static DEFINE_MUTEX(clocks_mutex);
  33 static DEFINE_SPINLOCK(clockfw_lock);
  34
  35 static struct clk_functions *arch_clock;
  36
  37 /**
  38  * omap_clk_for_each_child - call callback on each child clock of clk
  39  * @clk: struct clk * to use as the "parent"
  40  * @parent_rate: rate of the parent of @clk to pass along
  41  * @rate_storage: flag indicating whether current or temporary rates are used
  42  * @cb: pointer to a callback function
  43  *
  44  * For each child clock of @clk, call the callback function @cb, passing
  45  * along the contents of @parent_rate and @rate_storage.  If the callback
  46  * function returns non-zero, terminate the function and pass along the
  47  * return value.
  48  */
  49 static int omap_clk_for_each_child(struct clk *clk, unsigned long parent_rate,
  50                                    u8 rate_storage,
  51                                    int (*cb)(struct clk *clk,
  52                                              unsigned long parent_rate,
  53                                              u8 rate_storage))
  54 {
  55         struct clk_child *child;
  56         int ret;
  57
  58         list_for_each_entry(child, &clk->children, node) {
  59                 ret = (*cb)(child->clk, parent_rate, rate_storage);
  60                 if (ret)
  61                         break;
  62         }
  63
  64         return ret;
  65 }
  66
  67 /**
  68  * omap_clk_has_children - does clk @clk have any child clocks?
  69  * @clk: struct clk * to test for child clocks
  70  *
  71  * If clock @clk has any child clocks, return 1; otherwise, return 0.
  72  */
  73 static int omap_clk_has_children(struct clk *clk)
  74 {
  75         return (list_empty(&clk->children)) ? 0 : 1;
  76 }
  77
  78 /**
  79  * _do_propagate_rate - callback function for rate propagation
  80  * @clk: struct clk * to recalc and propagate from
  81  * @parent_rate: rate of the parent of @clk, to use in recalculation
  82  * @rate_storage: flag indicating whether current or temporary rates are used
  83  *
  84  * If @clk has a recalc function, call it.  If @clk has any children,
  85  * propagate @clk's rate.  Returns 0.
  86  */
  87 static int _do_propagate_rate(struct clk *clk, unsigned long parent_rate,
  88                               u8 rate_storage)
  89 {
  90         if (clk->recalc)
  91                 clk->recalc(clk, parent_rate, rate_storage);
  92         if (omap_clk_has_children(clk))
  93                 propagate_rate(clk, rate_storage);
  94         return 0;
  95 }
  96
  97 /**
  98  * omap_clk_add_child - add a child clock @clk2 to @clk
  99  * @clk: parent struct clk *
 100  * @clk2: new child struct clk *
 101  *
 102  * Add a child clock @clk2 to the list of children of parent clock
 103  * @clk.  Will potentially allocate memory from bootmem or, if
 104  * available, from slab.  Must only be called with the clock framework
 105  * spinlock held.  No return value.
 106  */
 107 void omap_clk_add_child(struct clk *clk, struct clk *clk2)
 108 {
 109         struct clk_child *child;
 110         int reuse = 0;
 111
 112         if (!clk->children.next)
 113                 INIT_LIST_HEAD(&clk->children);
 114
 115         list_for_each_entry(child, &clk->children, node) {
 116                 if (child->flags & CLK_CHILD_DELETED) {
 117                         reuse = 1;
 118                         child->flags &= ~CLK_CHILD_DELETED;
 119                         break;
 120                 }
 121         }
 122
 123         if (!reuse) {
 124                 if (slab_is_available())
 125                         child = kmalloc(sizeof(struct clk_child), GFP_ATOMIC);
 126                 else
 127                         child = alloc_bootmem(sizeof(struct clk_child));
 128
 129                 if (!child) {
 130                         WARN_ON(1);
 131                         return;
 132                 }
 133
 134                 memset(child, 0, sizeof(struct clk_child));
 135
 136                 if (slab_is_available())
 137                         child->flags |= CLK_CHILD_SLAB_ALLOC;
 138         }
 139
 140         child->clk = clk2;
 141
 142         list_add_tail(&child->node, &clk->children);
 143 }
 144
 145 /**
 146  * omap_clk_del_child - add a child clock @clk2 to @clk
 147  * @clk: parent struct clk *
 148  * @clk2: former child struct clk *
 149  *
 150  * Remove a child clock @clk2 from the list of children of parent
 151  * clock @clk.  Must only be called with the clock framework spinlock
 152  * held.  No return value.
 153  */
 154 void omap_clk_del_child(struct clk *clk, struct clk *clk2)
 155 {
 156         struct clk_child *child, *tmp;
 157
 158         /* Loop over all existing clk_childs, when found, deallocate */
 159         list_for_each_entry_safe(child, tmp, &clk->children, node) {
 160                 if (child->clk == clk2) {
 161                         list_del(&child->node);
 162                         if (child->flags & CLK_CHILD_SLAB_ALLOC) {
 163                                 kfree(child);
 164                         } else {
 165                                 child->clk = NULL;
 166                                 child->flags |= CLK_CHILD_DELETED;
 167                         }
 168                         break;
 169                 }
 170         }
 171 }
 172
 173 /*-------------------------------------------------------------------------
 174  * Standard clock functions defined in include/linux/clk.h
 175  *-------------------------------------------------------------------------*/
 176
 177 /*
 178  * Returns a clock. Note that we first try to use device id on the bus
 179  * and clock name. If this fails, we try to use clock name only.
 180  */
 181 struct clk * clk_get(struct device *dev, const char *id)
 182 {
 183         struct clk *p, *clk = ERR_PTR(-ENOENT);
 184         int idno;
 185
 186         if (dev == NULL || dev->bus != &platform_bus_type)
 187                 idno = -1;
 188         else
 189                 idno = to_platform_device(dev)->id;
 190
 191         mutex_lock(&clocks_mutex);
 192
 193         list_for_each_entry(p, &clocks, node) {
 194                 if (p->id == idno &&
 195                     strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
 196                         clk = p;
 197                         goto found;
 198                 }
 199         }
 200
 201         list_for_each_entry(p, &clocks, node) {
 202                 if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
 203                         clk = p;
 204                         break;
 205                 }
 206         }
 207
 208 found:
 209         mutex_unlock(&clocks_mutex);
 210
 211         return clk;
 212 }
 213 EXPORT_SYMBOL(clk_get);
 214
 215 int clk_enable(struct clk *clk)
 216 {
 217         unsigned long flags;
 218         int ret = 0;
 219
 220         if (clk == NULL || IS_ERR(clk))
 221                 return -EINVAL;
 222
 223         spin_lock_irqsave(&clockfw_lock, flags);
 224         if (arch_clock->clk_enable) {
 225                 ret = arch_clock->clk_enable(clk);
 226                 if (ret == 0 && clk->flags & RECALC_ON_ENABLE)
 227                         _do_propagate_rate(clk, clk->parent->rate,
 228                                            CURRENT_RATE);
 229         }
 230
 231         spin_unlock_irqrestore(&clockfw_lock, flags);
 232
 233         return ret;
 234 }
 235 EXPORT_SYMBOL(clk_enable);
 236
 237 void clk_disable(struct clk *clk)
 238 {
 239         unsigned long flags;
 240
 241         if (clk == NULL || IS_ERR(clk))
 242                 return;
 243
 244         spin_lock_irqsave(&clockfw_lock, flags);
 245         if (clk->usecount == 0) {
 246                 printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
 247                        clk->name);
 248                 WARN_ON(1);
 249                 goto out;
 250         }
 251
 252         if (arch_clock->clk_disable) {
 253                 arch_clock->clk_disable(clk);
 254                 if (clk->flags & RECALC_ON_ENABLE)
 255                         _do_propagate_rate(clk, clk->parent->rate,
 256                                            CURRENT_RATE);
 257         }
 258
 259 out:
 260         spin_unlock_irqrestore(&clockfw_lock, flags);
 261 }
 262 EXPORT_SYMBOL(clk_disable);
 263
 264 int clk_get_usecount(struct clk *clk)
 265 {
 266         unsigned long flags;
 267         int ret = 0;
 268
 269         if (clk == NULL || IS_ERR(clk))
 270                 return 0;
 271
 272         spin_lock_irqsave(&clockfw_lock, flags);
 273         ret = clk->usecount;
 274         spin_unlock_irqrestore(&clockfw_lock, flags);
 275
 276         return ret;
 277 }
 278 EXPORT_SYMBOL(clk_get_usecount);
 279
 280 unsigned long clk_get_rate(struct clk *clk)
 281 {
 282         unsigned long flags;
 283         unsigned long ret = 0;
 284
 285         if (clk == NULL || IS_ERR(clk))
 286                 return 0;
 287
 288         spin_lock_irqsave(&clockfw_lock, flags);
 289         ret = clk->rate;
 290         spin_unlock_irqrestore(&clockfw_lock, flags);
 291
 292         return ret;
 293 }
 294 EXPORT_SYMBOL(clk_get_rate);
 295
 296 void clk_put(struct clk *clk)
 297 {
 298         if (clk && !IS_ERR(clk))
 299                 module_put(clk->owner);
 300 }
 301 EXPORT_SYMBOL(clk_put);
 302
 303 /*-------------------------------------------------------------------------
 304  * Optional clock functions defined in include/linux/clk.h
 305  *-------------------------------------------------------------------------*/
 306
 307 long clk_round_rate(struct clk *clk, unsigned long rate)
 308 {
 309         unsigned long flags;
 310         long ret = 0;
 311
 312         if (clk == NULL || IS_ERR(clk))
 313                 return ret;
 314
 315         spin_lock_irqsave(&clockfw_lock, flags);
 316         if (arch_clock->clk_round_rate)
 317                 ret = arch_clock->clk_round_rate(clk, rate);
 318         spin_unlock_irqrestore(&clockfw_lock, flags);
 319
 320         return ret;
 321 }
 322 EXPORT_SYMBOL(clk_round_rate);
 323
 324 int clk_set_rate(struct clk *clk, unsigned long rate)
 325 {
 326         unsigned long flags;
 327         int ret = -EINVAL;
 328
 329         if (clk == NULL || IS_ERR(clk))
 330                 return ret;
 331
 332         spin_lock_irqsave(&clockfw_lock, flags);
 333
 334         if (arch_clock->clk_set_rate) {
 335                 ret = arch_clock->clk_set_rate(clk, rate);
 336                 if (ret == 0)
 337                         _do_propagate_rate(clk, clk->parent->rate,
 338                                            CURRENT_RATE);
 339         }
 340
 341         spin_unlock_irqrestore(&clockfw_lock, flags);
 342
 343         return ret;
 344 }
 345 EXPORT_SYMBOL(clk_set_rate);
 346
 347 int clk_set_parent(struct clk *clk, struct clk *parent)
 348 {
 349         unsigned long flags;
 350         struct clk *prev_parent;
 351         int ret = -EINVAL;
 352
 353         if (clk == NULL || IS_ERR(clk) || parent == NULL || IS_ERR(parent))
 354                 return ret;
 355
 356         spin_lock_irqsave(&clockfw_lock, flags);
 357
 358         if (arch_clock->clk_set_parent) {
 359                 prev_parent = clk->parent;
 360                 ret = arch_clock->clk_set_parent(clk, parent);
 361                 if (ret == 0) {
 362                         omap_clk_del_child(prev_parent, clk);
 363                         omap_clk_add_child(parent, clk);
 364                         _do_propagate_rate(clk, clk->parent->rate,
 365                                            CURRENT_RATE);
 366                 }
 367         }
 368
 369         spin_unlock_irqrestore(&clockfw_lock, flags);
 370
 371         return ret;
 372 }
 373 EXPORT_SYMBOL(clk_set_parent);
 374
 375 struct clk *clk_get_parent(struct clk *clk)
 376 {
 377         unsigned long flags;
 378         struct clk * ret = NULL;
 379
 380         if (clk == NULL || IS_ERR(clk))
 381                 return ret;
 382
 383         spin_lock_irqsave(&clockfw_lock, flags);
 384         if (arch_clock->clk_get_parent)
 385                 ret = arch_clock->clk_get_parent(clk);
 386         spin_unlock_irqrestore(&clockfw_lock, flags);
 387
 388         return ret;
 389 }
 390 EXPORT_SYMBOL(clk_get_parent);
 391
 392 /*-------------------------------------------------------------------------
 393  * OMAP specific clock functions shared between omap1 and omap2
 394  *-------------------------------------------------------------------------*/
 395
 396 unsigned int __initdata mpurate;
 397
 398 /*
 399  * By default we use the rate set by the bootloader.
 400  * You can override this with mpurate= cmdline option.
 401  */
 402 static int __init omap_clk_setup(char *str)
 403 {
 404         get_option(&str, &mpurate);
 405
 406         if (!mpurate)
 407                 return 1;
 408
 409         if (mpurate < 1000)
 410                 mpurate *= 1000000;
 411
 412         return 1;
 413 }
 414 __setup("mpurate=", omap_clk_setup);
 415
 416 /* Used for clocks that always have same value as the parent clock */
 417 void followparent_recalc(struct clk *clk, unsigned long new_parent_rate,
 418                          u8 rate_storage)
 419 {
 420         if (rate_storage == CURRENT_RATE)
 421                 clk->rate = new_parent_rate;
 422         else if (rate_storage == TEMP_RATE)
 423                 clk->temp_rate = new_parent_rate;
 424 }
 425
 426 /* Propagate rate to children */
 427 void propagate_rate(struct clk *tclk, u8 rate_storage)
 428 {
 429         unsigned long parent_rate = 0;
 430
 431         if (tclk == NULL || IS_ERR(tclk))
 432                 return;
 433
 434         if (rate_storage == CURRENT_RATE)
 435                 parent_rate = tclk->rate;
 436         else if (rate_storage == TEMP_RATE)
 437                 parent_rate = tclk->temp_rate;
 438
 439         omap_clk_for_each_child(tclk, parent_rate, rate_storage,
 440                                 _do_propagate_rate);
 441 }
 442
 443 /**
 444  * recalculate_root_clocks - recalculate and propagate all root clocks
 445  *
 446  * Recalculates all root clocks (clocks with no parent), which if the
 447  * clock's .recalc is set correctly, should also propagate their rates.
 448  * Called at init.
 449  */
 450 void recalculate_root_clocks(void)
 451 {
 452         struct clk *clkp;
 453
 454         list_for_each_entry(clkp, &clocks, node)
 455                 if (unlikely(!clkp->parent))
 456                         _do_propagate_rate(clkp, 0, CURRENT_RATE);
 457 }
 458
 459 int clk_register(struct clk *clk)
 460 {
 461         if (clk == NULL || IS_ERR(clk))
 462                 return -EINVAL;
 463
 464         mutex_lock(&clocks_mutex);
 465         list_add(&clk->node, &clocks);
 466         if (!clk->children.next)
 467                 INIT_LIST_HEAD(&clk->children);
 468         if (clk->parent)
 469                 omap_clk_add_child(clk->parent, clk);
 470         if (clk->init)
 471                 clk->init(clk);
 472         mutex_unlock(&clocks_mutex);
 473
 474         return 0;
 475 }
 476 EXPORT_SYMBOL(clk_register);
 477
 478 void clk_unregister(struct clk *clk)
 479 {
 480         struct clk_child *child, *tmp;
 481
 482         if (clk == NULL || IS_ERR(clk))
 483                 return;
 484
 485         mutex_lock(&clocks_mutex);
 486         list_del(&clk->node);
 487         if (clk->parent)
 488                 omap_clk_del_child(clk->parent, clk);
 489         list_for_each_entry_safe(child, tmp, &clk->children, node)
 490                 if (child->flags & CLK_CHILD_SLAB_ALLOC)
 491                         kfree(child);
 492         mutex_unlock(&clocks_mutex);
 493 }
 494 EXPORT_SYMBOL(clk_unregister);
 495
 496 void clk_deny_idle(struct clk *clk)
 497 {
 498         unsigned long flags;
 499
 500         if (clk == NULL || IS_ERR(clk))
 501                 return;
 502
 503         spin_lock_irqsave(&clockfw_lock, flags);
 504         if (arch_clock->clk_deny_idle)
 505                 arch_clock->clk_deny_idle(clk);
 506         spin_unlock_irqrestore(&clockfw_lock, flags);
 507 }
 508 EXPORT_SYMBOL(clk_deny_idle);
 509
 510 void clk_allow_idle(struct clk *clk)
 511 {
 512         unsigned long flags;
 513
 514         if (clk == NULL || IS_ERR(clk))
 515                 return;
 516
 517         spin_lock_irqsave(&clockfw_lock, flags);
 518         if (arch_clock->clk_allow_idle)
 519                 arch_clock->clk_allow_idle(clk);
 520         spin_unlock_irqrestore(&clockfw_lock, flags);
 521 }
 522 EXPORT_SYMBOL(clk_allow_idle);
 523
 524 void clk_enable_init_clocks(void)
 525 {
 526         struct clk *clkp;
 527
 528         list_for_each_entry(clkp, &clocks, node) {
 529                 if (clkp->flags & ENABLE_ON_INIT)
 530                         clk_enable(clkp);
 531         }
 532 }
 533 EXPORT_SYMBOL(clk_enable_init_clocks);
 534
 535 #ifdef CONFIG_CPU_FREQ
 536 void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
 537 {
 538         unsigned long flags;
 539
 540         spin_lock_irqsave(&clockfw_lock, flags);
 541         if (arch_clock->clk_init_cpufreq_table)
 542                 arch_clock->clk_init_cpufreq_table(table);
 543         spin_unlock_irqrestore(&clockfw_lock, flags);
 544 }
 545 EXPORT_SYMBOL(clk_init_cpufreq_table);
 546 #endif
 547
 548 /*-------------------------------------------------------------------------*/
 549
 550 #ifdef CONFIG_OMAP_RESET_CLOCKS
 551 /*
 552  * Disable any unused clocks left on by the bootloader
 553  */
 554 static int __init clk_disable_unused(void)
 555 {
 556         struct clk *ck;
 557         unsigned long flags;
 558
 559         list_for_each_entry(ck, &clocks, node) {
 560                 if (ck->usecount > 0 ||
 561                     (ck->flags & (ALWAYS_ENABLED | PARENT_CONTROLS_CLOCK)))
 562                         continue;
 563
 564                 if (cpu_class_is_omap1() && ck->enable_reg == 0)
 565                         continue;
 566
 567                 spin_lock_irqsave(&clockfw_lock, flags);
 568                 if (arch_clock->clk_disable_unused)
 569                         arch_clock->clk_disable_unused(ck);
 570                 spin_unlock_irqrestore(&clockfw_lock, flags);
 571         }
 572
 573         return 0;
 574 }
 575 late_initcall(clk_disable_unused);
 576 #endif
 577
 578 int __init clk_init(struct clk_functions * custom_clocks)
 579 {
 580         if (!custom_clocks) {
 581                 printk(KERN_ERR "No custom clock functions registered\n");
 582                 BUG();
 583         }
 584
 585         arch_clock = custom_clocks;
 586
 587         return 0;
 588 }
 589
 590 #if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
 591 /*
 592  *      debugfs support to trace clock tree hierarchy and attributes
 593  */
 594 static struct dentry *clk_debugfs_root;
 595
 596 static int clk_debugfs_register_one(struct clk *c)
 597 {
 598         int err;
 599         struct dentry *d, *child;
 600         struct clk *pa = c->parent;
 601         char s[255];
 602         char *p = s;
 603
 604         p += sprintf(p, "%s", c->name);
 605         if (c->id != 0)
 606                 sprintf(p, ":%d", c->id);
 607         d = debugfs_create_dir(s, pa ? pa->dent : clk_debugfs_root);
 608         if (!d)
 609                 return -ENOMEM;
 610         c->dent = d;
 611
 612         d = debugfs_create_u8("usecount", S_IRUGO, c->dent, (u8 *)&c->usecount);
 613         if (!d) {
 614                 err = -ENOMEM;
 615                 goto err_out;
 616         }
 617         d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
 618         if (!d) {
 619                 err = -ENOMEM;
 620                 goto err_out;
 621         }
 622         d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
 623         if (!d) {
 624                 err = -ENOMEM;
 625                 goto err_out;
 626         }
 627         return 0;
 628
 629 err_out:
 630         d = c->dent;
 631         list_for_each_entry(child, &d->d_subdirs, d_u.d_child)
 632                 debugfs_remove(child);
 633         debugfs_remove(c->dent);
 634         return err;
 635 }
 636
 637 static int clk_debugfs_register(struct clk *c)
 638 {
 639         int err;
 640         struct clk *pa = c->parent;
 641
 642         if (pa && !pa->dent) {
 643                 err = clk_debugfs_register(pa);
 644                 if (err)
 645                         return err;
 646         }
 647
 648         if (!c->dent) {
 649                 err = clk_debugfs_register_one(c);
 650                 if (err)
 651                         return err;
 652         }
 653         return 0;
 654 }
 655
 656 static int __init clk_debugfs_init(void)
 657 {
 658         struct clk *c;
 659         struct dentry *d;
 660         int err;
 661
 662         d = debugfs_create_dir("clock", NULL);
 663         if (!d)
 664                 return -ENOMEM;
 665         clk_debugfs_root = d;
 666
 667         list_for_each_entry(c, &clocks, node) {
 668                 err = clk_debugfs_register(c);
 669                 if (err)
 670                         goto err_out;
 671         }
 672         return 0;
 673 err_out:
 674         debugfs_remove(clk_debugfs_root); /* REVISIT: Cleanup correctly */
 675         return err;
 676 }
 677 late_initcall(clk_debugfs_init);
 678
 679 #endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */