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