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 && strcmp(id, p->name) == 0) {
 195                         clk = p;
 196                         goto found;
 197                 }
 198         }
 199
 200         list_for_each_entry(p, &clocks, node) {
 201                 if (strcmp(id, p->name) == 0) {
 202                         clk = p;
 203                         break;
 204                 }
 205         }
 206
 207 found:
 208         mutex_unlock(&clocks_mutex);
 209
 210         return clk;
 211 }
 212 EXPORT_SYMBOL(clk_get);
 213
 214 int clk_enable(struct clk *clk)
 215 {
 216         unsigned long flags;
 217         int ret = 0;
 218
 219         if (clk == NULL || IS_ERR(clk))
 220                 return -EINVAL;
 221
 222         spin_lock_irqsave(&clockfw_lock, flags);
 223         if (arch_clock->clk_enable) {
 224                 ret = arch_clock->clk_enable(clk);
 225                 if (ret == 0 && clk->flags & RECALC_ON_ENABLE)
 226                         _do_propagate_rate(clk, clk->parent->rate,
 227                                            CURRENT_RATE);
 228         }
 229
 230         spin_unlock_irqrestore(&clockfw_lock, flags);
 231
 232         return ret;
 233 }
 234 EXPORT_SYMBOL(clk_enable);
 235
 236 void clk_disable(struct clk *clk)
 237 {
 238         unsigned long flags;
 239
 240         if (clk == NULL || IS_ERR(clk))
 241                 return;
 242
 243         spin_lock_irqsave(&clockfw_lock, flags);
 244         if (clk->usecount == 0) {
 245                 printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
 246                        clk->name);
 247                 WARN_ON(1);
 248                 goto out;
 249         }
 250
 251         if (arch_clock->clk_disable) {
 252                 arch_clock->clk_disable(clk);
 253                 if (clk->flags & RECALC_ON_ENABLE)
 254                         _do_propagate_rate(clk, clk->parent->rate,
 255                                            CURRENT_RATE);
 256         }
 257
 258 out:
 259         spin_unlock_irqrestore(&clockfw_lock, flags);
 260 }
 261 EXPORT_SYMBOL(clk_disable);
 262
 263 int clk_get_usecount(struct clk *clk)
 264 {
 265         unsigned long flags;
 266         int ret = 0;
 267
 268         if (clk == NULL || IS_ERR(clk))
 269                 return 0;
 270
 271         spin_lock_irqsave(&clockfw_lock, flags);
 272         ret = clk->usecount;
 273         spin_unlock_irqrestore(&clockfw_lock, flags);
 274
 275         return ret;
 276 }
 277 EXPORT_SYMBOL(clk_get_usecount);
 278
 279 unsigned long clk_get_rate(struct clk *clk)
 280 {
 281         unsigned long flags;
 282         unsigned long ret = 0;
 283
 284         if (clk == NULL || IS_ERR(clk))
 285                 return 0;
 286
 287         spin_lock_irqsave(&clockfw_lock, flags);
 288         ret = clk->rate;
 289         spin_unlock_irqrestore(&clockfw_lock, flags);
 290
 291         return ret;
 292 }
 293 EXPORT_SYMBOL(clk_get_rate);
 294
 295 void clk_put(struct clk *clk)
 296 {
 297 }
 298 EXPORT_SYMBOL(clk_put);
 299
 300 /*-------------------------------------------------------------------------
 301  * Optional clock functions defined in include/linux/clk.h
 302  *-------------------------------------------------------------------------*/
 303
 304 long clk_round_rate(struct clk *clk, unsigned long rate)
 305 {
 306         unsigned long flags;
 307         long ret = 0;
 308
 309         if (clk == NULL || IS_ERR(clk))
 310                 return ret;
 311
 312         spin_lock_irqsave(&clockfw_lock, flags);
 313         if (arch_clock->clk_round_rate)
 314                 ret = arch_clock->clk_round_rate(clk, rate);
 315         spin_unlock_irqrestore(&clockfw_lock, flags);
 316
 317         return ret;
 318 }
 319 EXPORT_SYMBOL(clk_round_rate);
 320
 321 int clk_set_rate(struct clk *clk, unsigned long rate)
 322 {
 323         unsigned long flags;
 324         int ret = -EINVAL;
 325
 326         if (clk == NULL || IS_ERR(clk))
 327                 return ret;
 328
 329         spin_lock_irqsave(&clockfw_lock, flags);
 330
 331         if (arch_clock->clk_set_rate) {
 332                 ret = arch_clock->clk_set_rate(clk, rate);
 333                 if (ret == 0)
 334                         _do_propagate_rate(clk, clk->parent->rate,
 335                                            CURRENT_RATE);
 336         }
 337
 338         spin_unlock_irqrestore(&clockfw_lock, flags);
 339
 340         return ret;
 341 }
 342 EXPORT_SYMBOL(clk_set_rate);
 343
 344 int clk_set_parent(struct clk *clk, struct clk *parent)
 345 {
 346         unsigned long flags;
 347         struct clk *prev_parent;
 348         int ret = -EINVAL;
 349
 350         if (clk == NULL || IS_ERR(clk) || parent == NULL || IS_ERR(parent))
 351                 return ret;
 352
 353         spin_lock_irqsave(&clockfw_lock, flags);
 354
 355         if (arch_clock->clk_set_parent) {
 356                 prev_parent = clk->parent;
 357                 ret = arch_clock->clk_set_parent(clk, parent);
 358                 if (ret == 0) {
 359                         omap_clk_del_child(prev_parent, clk);
 360                         omap_clk_add_child(parent, clk);
 361                         _do_propagate_rate(clk, clk->parent->rate,
 362                                            CURRENT_RATE);
 363                 }
 364         }
 365
 366         spin_unlock_irqrestore(&clockfw_lock, flags);
 367
 368         return ret;
 369 }
 370 EXPORT_SYMBOL(clk_set_parent);
 371
 372 struct clk *clk_get_parent(struct clk *clk)
 373 {
 374         unsigned long flags;
 375         struct clk * ret = NULL;
 376
 377         if (clk == NULL || IS_ERR(clk))
 378                 return ret;
 379
 380         spin_lock_irqsave(&clockfw_lock, flags);
 381         if (arch_clock->clk_get_parent)
 382                 ret = arch_clock->clk_get_parent(clk);
 383         spin_unlock_irqrestore(&clockfw_lock, flags);
 384
 385         return ret;
 386 }
 387 EXPORT_SYMBOL(clk_get_parent);
 388
 389 /*-------------------------------------------------------------------------
 390  * OMAP specific clock functions shared between omap1 and omap2
 391  *-------------------------------------------------------------------------*/
 392
 393 unsigned int __initdata mpurate;
 394
 395 /*
 396  * By default we use the rate set by the bootloader.
 397  * You can override this with mpurate= cmdline option.
 398  */
 399 static int __init omap_clk_setup(char *str)
 400 {
 401         get_option(&str, &mpurate);
 402
 403         if (!mpurate)
 404                 return 1;
 405
 406         if (mpurate < 1000)
 407                 mpurate *= 1000000;
 408
 409         return 1;
 410 }
 411 __setup("mpurate=", omap_clk_setup);
 412
 413 /* Used for clocks that always have same value as the parent clock */
 414 void followparent_recalc(struct clk *clk, unsigned long new_parent_rate,
 415                          u8 rate_storage)
 416 {
 417         if (rate_storage == CURRENT_RATE)
 418                 clk->rate = new_parent_rate;
 419         else if (rate_storage == TEMP_RATE)
 420                 clk->temp_rate = new_parent_rate;
 421 }
 422
 423 /* Propagate rate to children */
 424 void propagate_rate(struct clk *tclk, u8 rate_storage)
 425 {
 426         unsigned long parent_rate = 0;
 427
 428         if (tclk == NULL || IS_ERR(tclk))
 429                 return;
 430
 431         if (rate_storage == CURRENT_RATE)
 432                 parent_rate = tclk->rate;
 433         else if (rate_storage == TEMP_RATE)
 434                 parent_rate = tclk->temp_rate;
 435
 436         omap_clk_for_each_child(tclk, parent_rate, rate_storage,
 437                                 _do_propagate_rate);
 438 }
 439
 440 /**
 441  * recalculate_root_clocks - recalculate and propagate all root clocks
 442  *
 443  * Recalculates all root clocks (clocks with no parent), which if the
 444  * clock's .recalc is set correctly, should also propagate their rates.
 445  * Called at init.
 446  */
 447 void recalculate_root_clocks(void)
 448 {
 449         struct clk *clkp;
 450
 451         list_for_each_entry(clkp, &clocks, node)
 452                 if (unlikely(!clkp->parent))
 453                         _do_propagate_rate(clkp, 0, CURRENT_RATE);
 454 }
 455
 456 int clk_register(struct clk *clk)
 457 {
 458         if (clk == NULL || IS_ERR(clk))
 459                 return -EINVAL;
 460
 461         mutex_lock(&clocks_mutex);
 462         list_add(&clk->node, &clocks);
 463         if (!clk->children.next)
 464                 INIT_LIST_HEAD(&clk->children);
 465         if (clk->parent)
 466                 omap_clk_add_child(clk->parent, clk);
 467         if (clk->init)
 468                 clk->init(clk);
 469         mutex_unlock(&clocks_mutex);
 470
 471         return 0;
 472 }
 473 EXPORT_SYMBOL(clk_register);
 474
 475 void clk_unregister(struct clk *clk)
 476 {
 477         struct clk_child *child, *tmp;
 478
 479         if (clk == NULL || IS_ERR(clk))
 480                 return;
 481
 482         mutex_lock(&clocks_mutex);
 483         list_del(&clk->node);
 484         if (clk->parent)
 485                 omap_clk_del_child(clk->parent, clk);
 486         list_for_each_entry_safe(child, tmp, &clk->children, node)
 487                 if (child->flags & CLK_CHILD_SLAB_ALLOC)
 488                         kfree(child);
 489         mutex_unlock(&clocks_mutex);
 490 }
 491 EXPORT_SYMBOL(clk_unregister);
 492
 493 void clk_deny_idle(struct clk *clk)
 494 {
 495         unsigned long flags;
 496
 497         if (clk == NULL || IS_ERR(clk))
 498                 return;
 499
 500         spin_lock_irqsave(&clockfw_lock, flags);
 501         if (arch_clock->clk_deny_idle)
 502                 arch_clock->clk_deny_idle(clk);
 503         spin_unlock_irqrestore(&clockfw_lock, flags);
 504 }
 505 EXPORT_SYMBOL(clk_deny_idle);
 506
 507 void clk_allow_idle(struct clk *clk)
 508 {
 509         unsigned long flags;
 510
 511         if (clk == NULL || IS_ERR(clk))
 512                 return;
 513
 514         spin_lock_irqsave(&clockfw_lock, flags);
 515         if (arch_clock->clk_allow_idle)
 516                 arch_clock->clk_allow_idle(clk);
 517         spin_unlock_irqrestore(&clockfw_lock, flags);
 518 }
 519 EXPORT_SYMBOL(clk_allow_idle);
 520
 521 void clk_enable_init_clocks(void)
 522 {
 523         struct clk *clkp;
 524
 525         list_for_each_entry(clkp, &clocks, node) {
 526                 if (clkp->flags & ENABLE_ON_INIT)
 527                         clk_enable(clkp);
 528         }
 529 }
 530 EXPORT_SYMBOL(clk_enable_init_clocks);
 531
 532 #ifdef CONFIG_CPU_FREQ
 533 void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
 534 {
 535         unsigned long flags;
 536
 537         spin_lock_irqsave(&clockfw_lock, flags);
 538         if (arch_clock->clk_init_cpufreq_table)
 539                 arch_clock->clk_init_cpufreq_table(table);
 540         spin_unlock_irqrestore(&clockfw_lock, flags);
 541 }
 542 EXPORT_SYMBOL(clk_init_cpufreq_table);
 543 #endif
 544
 545 /*-------------------------------------------------------------------------*/
 546
 547 #ifdef CONFIG_OMAP_RESET_CLOCKS
 548 /*
 549  * Disable any unused clocks left on by the bootloader
 550  */
 551 static int __init clk_disable_unused(void)
 552 {
 553         struct clk *ck;
 554         unsigned long flags;
 555
 556         list_for_each_entry(ck, &clocks, node) {
 557                 if (ck->usecount > 0 ||
 558                     (ck->flags & (ALWAYS_ENABLED | PARENT_CONTROLS_CLOCK)))
 559                         continue;
 560
 561                 if (cpu_class_is_omap1() && ck->enable_reg == 0)
 562                         continue;
 563
 564                 spin_lock_irqsave(&clockfw_lock, flags);
 565                 if (arch_clock->clk_disable_unused)
 566                         arch_clock->clk_disable_unused(ck);
 567                 spin_unlock_irqrestore(&clockfw_lock, flags);
 568         }
 569
 570         return 0;
 571 }
 572 late_initcall(clk_disable_unused);
 573 #endif
 574
 575 int __init clk_init(struct clk_functions * custom_clocks)
 576 {
 577         if (!custom_clocks) {
 578                 printk(KERN_ERR "No custom clock functions registered\n");
 579                 BUG();
 580         }
 581
 582         arch_clock = custom_clocks;
 583
 584         return 0;
 585 }
 586
 587 #if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
 588 /*
 589  *      debugfs support to trace clock tree hierarchy and attributes
 590  */
 591 static struct dentry *clk_debugfs_root;
 592
 593 static int clk_debugfs_register_one(struct clk *c)
 594 {
 595         int err;
 596         struct dentry *d, *child;
 597         struct clk *pa = c->parent;
 598         char s[255];
 599         char *p = s;
 600
 601         p += sprintf(p, "%s", c->name);
 602         if (c->id != 0)
 603                 sprintf(p, ":%d", c->id);
 604         d = debugfs_create_dir(s, pa ? pa->dent : clk_debugfs_root);
 605         if (!d)
 606                 return -ENOMEM;
 607         c->dent = d;
 608
 609         d = debugfs_create_u8("usecount", S_IRUGO, c->dent, (u8 *)&c->usecount);
 610         if (!d) {
 611                 err = -ENOMEM;
 612                 goto err_out;
 613         }
 614         d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
 615         if (!d) {
 616                 err = -ENOMEM;
 617                 goto err_out;
 618         }
 619         d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
 620         if (!d) {
 621                 err = -ENOMEM;
 622                 goto err_out;
 623         }
 624         return 0;
 625
 626 err_out:
 627         d = c->dent;
 628         list_for_each_entry(child, &d->d_subdirs, d_u.d_child)
 629                 debugfs_remove(child);
 630         debugfs_remove(c->dent);
 631         return err;
 632 }
 633
 634 static int clk_debugfs_register(struct clk *c)
 635 {
 636         int err;
 637         struct clk *pa = c->parent;
 638
 639         if (pa && !pa->dent) {
 640                 err = clk_debugfs_register(pa);
 641                 if (err)
 642                         return err;
 643         }
 644
 645         if (!c->dent) {
 646                 err = clk_debugfs_register_one(c);
 647                 if (err)
 648                         return err;
 649         }
 650         return 0;
 651 }
 652
 653 static int __init clk_debugfs_init(void)
 654 {
 655         struct clk *c;
 656         struct dentry *d;
 657         int err;
 658
 659         d = debugfs_create_dir("clock", NULL);
 660         if (!d)
 661                 return -ENOMEM;
 662         clk_debugfs_root = d;
 663
 664         list_for_each_entry(c, &clocks, node) {
 665                 err = clk_debugfs_register(c);
 666                 if (err)
 667                         goto err_out;
 668         }
 669         return 0;
 670 err_out:
 671         debugfs_remove(clk_debugfs_root); /* REVISIT: Cleanup correctly */
 672         return err;
 673 }
 674 late_initcall(clk_debugfs_init);
 675
 676 #endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */