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/list.h>
  16 #include <linux/errno.h>
  17 #include <linux/err.h>
  18 #include <linux/string.h>
  19 #include <linux/clk.h>
  20 #include <linux/mutex.h>
  21 #include <linux/cpufreq.h>
  22 #include <linux/debugfs.h>
  23 #include <linux/io.h>
  24
  25 #include <plat/clock.h>
  26
  27 static LIST_HEAD(clocks);
  28 static DEFINE_MUTEX(clocks_mutex);
  29 static DEFINE_SPINLOCK(clockfw_lock);
  30
  31 static struct clk_functions *arch_clock;
  32
  33 /*
  34  * Standard clock functions defined in include/linux/clk.h
  35  */
  36
  37 int clk_enable(struct clk *clk)
  38 {
  39         unsigned long flags;
  40         int ret;
  41
  42         if (clk == NULL || IS_ERR(clk))
  43                 return -EINVAL;
  44
  45         if (!arch_clock || !arch_clock->clk_enable)
  46                 return -EINVAL;
  47
  48         spin_lock_irqsave(&clockfw_lock, flags);
  49         ret = arch_clock->clk_enable(clk);
  50         spin_unlock_irqrestore(&clockfw_lock, flags);
  51
  52         return ret;
  53 }
  54 EXPORT_SYMBOL(clk_enable);
  55
  56 void clk_disable(struct clk *clk)
  57 {
  58         unsigned long flags;
  59
  60         if (clk == NULL || IS_ERR(clk))
  61                 return;
  62
  63         if (!arch_clock || !arch_clock->clk_disable)
  64                 return;
  65
  66         spin_lock_irqsave(&clockfw_lock, flags);
  67         if (clk->usecount == 0) {
  68                 pr_err("Trying disable clock %s with 0 usecount\n",
  69                        clk->name);
  70                 WARN_ON(1);
  71                 goto out;
  72         }
  73
  74         arch_clock->clk_disable(clk);
  75
  76 out:
  77         spin_unlock_irqrestore(&clockfw_lock, flags);
  78 }
  79 EXPORT_SYMBOL(clk_disable);
  80
  81 unsigned long clk_get_rate(struct clk *clk)
  82 {
  83         unsigned long flags;
  84         unsigned long ret;
  85
  86         if (clk == NULL || IS_ERR(clk))
  87                 return 0;
  88
  89         spin_lock_irqsave(&clockfw_lock, flags);
  90         ret = clk->rate;
  91         spin_unlock_irqrestore(&clockfw_lock, flags);
  92
  93         return ret;
  94 }
  95 EXPORT_SYMBOL(clk_get_rate);
  96
  97 /*
  98  * Optional clock functions defined in include/linux/clk.h
  99  */
 100
 101 long clk_round_rate(struct clk *clk, unsigned long rate)
 102 {
 103         unsigned long flags;
 104         long ret;
 105
 106         if (clk == NULL || IS_ERR(clk))
 107                 return 0;
 108
 109         if (!arch_clock || !arch_clock->clk_round_rate)
 110                 return 0;
 111
 112         spin_lock_irqsave(&clockfw_lock, flags);
 113         ret = arch_clock->clk_round_rate(clk, rate);
 114         spin_unlock_irqrestore(&clockfw_lock, flags);
 115
 116         return ret;
 117 }
 118 EXPORT_SYMBOL(clk_round_rate);
 119
 120 int clk_set_rate(struct clk *clk, unsigned long rate)
 121 {
 122         unsigned long flags;
 123         int ret = -EINVAL;
 124
 125         if (clk == NULL || IS_ERR(clk))
 126                 return ret;
 127
 128         if (!arch_clock || !arch_clock->clk_set_rate)
 129                 return ret;
 130
 131         spin_lock_irqsave(&clockfw_lock, flags);
 132         ret = arch_clock->clk_set_rate(clk, rate);
 133         if (ret == 0)
 134                 propagate_rate(clk);
 135         spin_unlock_irqrestore(&clockfw_lock, flags);
 136
 137         return ret;
 138 }
 139 EXPORT_SYMBOL(clk_set_rate);
 140
 141 int clk_set_parent(struct clk *clk, struct clk *parent)
 142 {
 143         unsigned long flags;
 144         int ret = -EINVAL;
 145
 146         if (clk == NULL || IS_ERR(clk) || parent == NULL || IS_ERR(parent))
 147                 return ret;
 148
 149         if (!arch_clock || !arch_clock->clk_set_parent)
 150                 return ret;
 151
 152         spin_lock_irqsave(&clockfw_lock, flags);
 153         if (clk->usecount == 0) {
 154                 ret = arch_clock->clk_set_parent(clk, parent);
 155                 if (ret == 0)
 156                         propagate_rate(clk);
 157         } else
 158                 ret = -EBUSY;
 159         spin_unlock_irqrestore(&clockfw_lock, flags);
 160
 161         return ret;
 162 }
 163 EXPORT_SYMBOL(clk_set_parent);
 164
 165 struct clk *clk_get_parent(struct clk *clk)
 166 {
 167         return clk->parent;
 168 }
 169 EXPORT_SYMBOL(clk_get_parent);
 170
 171 /*
 172  * OMAP specific clock functions shared between omap1 and omap2
 173  */
 174
 175 int __initdata mpurate;
 176
 177 /*
 178  * By default we use the rate set by the bootloader.
 179  * You can override this with mpurate= cmdline option.
 180  */
 181 static int __init omap_clk_setup(char *str)
 182 {
 183         get_option(&str, &mpurate);
 184
 185         if (!mpurate)
 186                 return 1;
 187
 188         if (mpurate < 1000)
 189                 mpurate *= 1000000;
 190
 191         return 1;
 192 }
 193 __setup("mpurate=", omap_clk_setup);
 194
 195 /* Used for clocks that always have same value as the parent clock */
 196 unsigned long followparent_recalc(struct clk *clk)
 197 {
 198         return clk->parent->rate;
 199 }
 200
 201 /*
 202  * Used for clocks that have the same value as the parent clock,
 203  * divided by some factor
 204  */
 205 unsigned long omap_fixed_divisor_recalc(struct clk *clk)
 206 {
 207         WARN_ON(!clk->fixed_div);
 208
 209         return clk->parent->rate / clk->fixed_div;
 210 }
 211
 212 void clk_reparent(struct clk *child, struct clk *parent)
 213 {
 214         list_del_init(&child->sibling);
 215         if (parent)
 216                 list_add(&child->sibling, &parent->children);
 217         child->parent = parent;
 218
 219         /* now do the debugfs renaming to reattach the child
 220            to the proper parent */
 221 }
 222
 223 /* Propagate rate to children */
 224 void propagate_rate(struct clk *tclk)
 225 {
 226         struct clk *clkp;
 227
 228         list_for_each_entry(clkp, &tclk->children, sibling) {
 229                 if (clkp->recalc)
 230                         clkp->rate = clkp->recalc(clkp);
 231                 propagate_rate(clkp);
 232         }
 233 }
 234
 235 static LIST_HEAD(root_clks);
 236
 237 /**
 238  * recalculate_root_clocks - recalculate and propagate all root clocks
 239  *
 240  * Recalculates all root clocks (clocks with no parent), which if the
 241  * clock's .recalc is set correctly, should also propagate their rates.
 242  * Called at init.
 243  */
 244 void recalculate_root_clocks(void)
 245 {
 246         struct clk *clkp;
 247
 248         list_for_each_entry(clkp, &root_clks, sibling) {
 249                 if (clkp->recalc)
 250                         clkp->rate = clkp->recalc(clkp);
 251                 propagate_rate(clkp);
 252         }
 253 }
 254
 255 /**
 256  * clk_preinit - initialize any fields in the struct clk before clk init
 257  * @clk: struct clk * to initialize
 258  *
 259  * Initialize any struct clk fields needed before normal clk initialization
 260  * can run.  No return value.
 261  */
 262 void clk_preinit(struct clk *clk)
 263 {
 264         INIT_LIST_HEAD(&clk->children);
 265 }
 266
 267 int clk_register(struct clk *clk)
 268 {
 269         if (clk == NULL || IS_ERR(clk))
 270                 return -EINVAL;
 271
 272         /*
 273          * trap out already registered clocks
 274          */
 275         if (clk->node.next || clk->node.prev)
 276                 return 0;
 277
 278         mutex_lock(&clocks_mutex);
 279         if (clk->parent)
 280                 list_add(&clk->sibling, &clk->parent->children);
 281         else
 282                 list_add(&clk->sibling, &root_clks);
 283
 284         list_add(&clk->node, &clocks);
 285         if (clk->init)
 286                 clk->init(clk);
 287         mutex_unlock(&clocks_mutex);
 288
 289         return 0;
 290 }
 291 EXPORT_SYMBOL(clk_register);
 292
 293 void clk_unregister(struct clk *clk)
 294 {
 295         if (clk == NULL || IS_ERR(clk))
 296                 return;
 297
 298         mutex_lock(&clocks_mutex);
 299         list_del(&clk->sibling);
 300         list_del(&clk->node);
 301         mutex_unlock(&clocks_mutex);
 302 }
 303 EXPORT_SYMBOL(clk_unregister);
 304
 305 void clk_enable_init_clocks(void)
 306 {
 307         struct clk *clkp;
 308
 309         list_for_each_entry(clkp, &clocks, node) {
 310                 if (clkp->flags & ENABLE_ON_INIT)
 311                         clk_enable(clkp);
 312         }
 313 }
 314
 315 /**
 316  * omap_clk_get_by_name - locate OMAP struct clk by its name
 317  * @name: name of the struct clk to locate
 318  *
 319  * Locate an OMAP struct clk by its name.  Assumes that struct clk
 320  * names are unique.  Returns NULL if not found or a pointer to the
 321  * struct clk if found.
 322  */
 323 struct clk *omap_clk_get_by_name(const char *name)
 324 {
 325         struct clk *c;
 326         struct clk *ret = NULL;
 327
 328         mutex_lock(&clocks_mutex);
 329
 330         list_for_each_entry(c, &clocks, node) {
 331                 if (!strcmp(c->name, name)) {
 332                         ret = c;
 333                         break;
 334                 }
 335         }
 336
 337         mutex_unlock(&clocks_mutex);
 338
 339         return ret;
 340 }
 341
 342 int omap_clk_enable_autoidle_all(void)
 343 {
 344         struct clk *c;
 345         unsigned long flags;
 346
 347         spin_lock_irqsave(&clockfw_lock, flags);
 348
 349         list_for_each_entry(c, &clocks, node)
 350                 if (c->ops->allow_idle)
 351                         c->ops->allow_idle(c);
 352
 353         spin_unlock_irqrestore(&clockfw_lock, flags);
 354
 355         return 0;
 356 }
 357
 358 int omap_clk_disable_autoidle_all(void)
 359 {
 360         struct clk *c;
 361         unsigned long flags;
 362
 363         spin_lock_irqsave(&clockfw_lock, flags);
 364
 365         list_for_each_entry(c, &clocks, node)
 366                 if (c->ops->deny_idle)
 367                         c->ops->deny_idle(c);
 368
 369         spin_unlock_irqrestore(&clockfw_lock, flags);
 370
 371         return 0;
 372 }
 373
 374 /*
 375  * Low level helpers
 376  */
 377 static int clkll_enable_null(struct clk *clk)
 378 {
 379         return 0;
 380 }
 381
 382 static void clkll_disable_null(struct clk *clk)
 383 {
 384 }
 385
 386 const struct clkops clkops_null = {
 387         .enable         = clkll_enable_null,
 388         .disable        = clkll_disable_null,
 389 };
 390
 391 /*
 392  * Dummy clock
 393  *
 394  * Used for clock aliases that are needed on some OMAPs, but not others
 395  */
 396 struct clk dummy_ck = {
 397         .name   = "dummy",
 398         .ops    = &clkops_null,
 399 };
 400
 401 #ifdef CONFIG_CPU_FREQ
 402 void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
 403 {
 404         unsigned long flags;
 405
 406         if (!arch_clock || !arch_clock->clk_init_cpufreq_table)
 407                 return;
 408
 409         spin_lock_irqsave(&clockfw_lock, flags);
 410         arch_clock->clk_init_cpufreq_table(table);
 411         spin_unlock_irqrestore(&clockfw_lock, flags);
 412 }
 413
 414 void clk_exit_cpufreq_table(struct cpufreq_frequency_table **table)
 415 {
 416         unsigned long flags;
 417
 418         if (!arch_clock || !arch_clock->clk_exit_cpufreq_table)
 419                 return;
 420
 421         spin_lock_irqsave(&clockfw_lock, flags);
 422         arch_clock->clk_exit_cpufreq_table(table);
 423         spin_unlock_irqrestore(&clockfw_lock, flags);
 424 }
 425 #endif
 426
 427 /*
 428  *
 429  */
 430
 431 #ifdef CONFIG_OMAP_RESET_CLOCKS
 432 /*
 433  * Disable any unused clocks left on by the bootloader
 434  */
 435 static int __init clk_disable_unused(void)
 436 {
 437         struct clk *ck;
 438         unsigned long flags;
 439
 440         if (!arch_clock || !arch_clock->clk_disable_unused)
 441                 return 0;
 442
 443         pr_info("clock: disabling unused clocks to save power\n");
 444         list_for_each_entry(ck, &clocks, node) {
 445                 if (ck->ops == &clkops_null)
 446                         continue;
 447
 448                 if (ck->usecount > 0 || !ck->enable_reg)
 449                         continue;
 450
 451                 spin_lock_irqsave(&clockfw_lock, flags);
 452                 arch_clock->clk_disable_unused(ck);
 453                 spin_unlock_irqrestore(&clockfw_lock, flags);
 454         }
 455
 456         return 0;
 457 }
 458 late_initcall(clk_disable_unused);
 459 late_initcall(omap_clk_enable_autoidle_all);
 460 #endif
 461
 462 int __init clk_init(struct clk_functions * custom_clocks)
 463 {
 464         if (!custom_clocks) {
 465                 pr_err("No custom clock functions registered\n");
 466                 BUG();
 467         }
 468
 469         arch_clock = custom_clocks;
 470
 471         return 0;
 472 }
 473
 474 #if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
 475 /*
 476  *      debugfs support to trace clock tree hierarchy and attributes
 477  */
 478 static struct dentry *clk_debugfs_root;
 479
 480 static int clk_debugfs_register_one(struct clk *c)
 481 {
 482         int err;
 483         struct dentry *d;
 484         struct clk *pa = c->parent;
 485
 486         d = debugfs_create_dir(c->name, pa ? pa->dent : clk_debugfs_root);
 487         if (!d)
 488                 return -ENOMEM;
 489         c->dent = d;
 490
 491         d = debugfs_create_u8("usecount", S_IRUGO, c->dent, (u8 *)&c->usecount);
 492         if (!d) {
 493                 err = -ENOMEM;
 494                 goto err_out;
 495         }
 496         d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
 497         if (!d) {
 498                 err = -ENOMEM;
 499                 goto err_out;
 500         }
 501         d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
 502         if (!d) {
 503                 err = -ENOMEM;
 504                 goto err_out;
 505         }
 506         return 0;
 507
 508 err_out:
 509         debugfs_remove_recursive(c->dent);
 510         return err;
 511 }
 512
 513 static int clk_debugfs_register(struct clk *c)
 514 {
 515         int err;
 516         struct clk *pa = c->parent;
 517
 518         if (pa && !pa->dent) {
 519                 err = clk_debugfs_register(pa);
 520                 if (err)
 521                         return err;
 522         }
 523
 524         if (!c->dent) {
 525                 err = clk_debugfs_register_one(c);
 526                 if (err)
 527                         return err;
 528         }
 529         return 0;
 530 }
 531
 532 static int __init clk_debugfs_init(void)
 533 {
 534         struct clk *c;
 535         struct dentry *d;
 536         int err;
 537
 538         d = debugfs_create_dir("clock", NULL);
 539         if (!d)
 540                 return -ENOMEM;
 541         clk_debugfs_root = d;
 542
 543         list_for_each_entry(c, &clocks, node) {
 544                 err = clk_debugfs_register(c);
 545                 if (err)
 546                         goto err_out;
 547         }
 548         return 0;
 549 err_out:
 550         debugfs_remove_recursive(clk_debugfs_root);
 551         return err;
 552 }
 553 late_initcall(clk_debugfs_init);
 554
 555 #endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */