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/export.h>
  18 #include <linux/err.h>
  19 #include <linux/string.h>
  20 #include <linux/clk.h>
  21 #include <linux/mutex.h>
  22 #include <linux/cpufreq.h>
  23 #include <linux/debugfs.h>
  24 #include <linux/io.h>
  25
  26 #include <plat/clock.h>
  27
  28 static LIST_HEAD(clocks);
  29 static DEFINE_MUTEX(clocks_mutex);
  30 static DEFINE_SPINLOCK(clockfw_lock);
  31
  32 static struct clk_functions *arch_clock;
  33
  34 /*
  35  * Standard clock functions defined in include/linux/clk.h
  36  */
  37
  38 int clk_enable(struct clk *clk)
  39 {
  40         unsigned long flags;
  41         int ret;
  42
  43         if (clk == NULL || IS_ERR(clk))
  44                 return -EINVAL;
  45
  46         if (!arch_clock || !arch_clock->clk_enable)
  47                 return -EINVAL;
  48
  49         spin_lock_irqsave(&clockfw_lock, flags);
  50         ret = arch_clock->clk_enable(clk);
  51         spin_unlock_irqrestore(&clockfw_lock, flags);
  52
  53         return ret;
  54 }
  55 EXPORT_SYMBOL(clk_enable);
  56
  57 void clk_disable(struct clk *clk)
  58 {
  59         unsigned long flags;
  60
  61         if (clk == NULL || IS_ERR(clk))
  62                 return;
  63
  64         if (!arch_clock || !arch_clock->clk_disable)
  65                 return;
  66
  67         spin_lock_irqsave(&clockfw_lock, flags);
  68         if (clk->usecount == 0) {
  69                 pr_err("Trying disable clock %s with 0 usecount\n",
  70                        clk->name);
  71                 WARN_ON(1);
  72                 goto out;
  73         }
  74
  75         arch_clock->clk_disable(clk);
  76
  77 out:
  78         spin_unlock_irqrestore(&clockfw_lock, flags);
  79 }
  80 EXPORT_SYMBOL(clk_disable);
  81
  82 unsigned long clk_get_rate(struct clk *clk)
  83 {
  84         unsigned long flags;
  85         unsigned long ret;
  86
  87         if (clk == NULL || IS_ERR(clk))
  88                 return 0;
  89
  90         spin_lock_irqsave(&clockfw_lock, flags);
  91         ret = clk->rate;
  92         spin_unlock_irqrestore(&clockfw_lock, flags);
  93
  94         return ret;
  95 }
  96 EXPORT_SYMBOL(clk_get_rate);
  97
  98 /*
  99  * Optional clock functions defined in include/linux/clk.h
 100  */
 101
 102 long clk_round_rate(struct clk *clk, unsigned long rate)
 103 {
 104         unsigned long flags;
 105         long ret;
 106
 107         if (clk == NULL || IS_ERR(clk))
 108                 return 0;
 109
 110         if (!arch_clock || !arch_clock->clk_round_rate)
 111                 return 0;
 112
 113         spin_lock_irqsave(&clockfw_lock, flags);
 114         ret = arch_clock->clk_round_rate(clk, rate);
 115         spin_unlock_irqrestore(&clockfw_lock, flags);
 116
 117         return ret;
 118 }
 119 EXPORT_SYMBOL(clk_round_rate);
 120
 121 int clk_set_rate(struct clk *clk, unsigned long rate)
 122 {
 123         unsigned long flags;
 124         int ret = -EINVAL;
 125
 126         if (clk == NULL || IS_ERR(clk))
 127                 return ret;
 128
 129         if (!arch_clock || !arch_clock->clk_set_rate)
 130                 return ret;
 131
 132         spin_lock_irqsave(&clockfw_lock, flags);
 133         ret = arch_clock->clk_set_rate(clk, rate);
 134         if (ret == 0)
 135                 propagate_rate(clk);
 136         spin_unlock_irqrestore(&clockfw_lock, flags);
 137
 138         return ret;
 139 }
 140 EXPORT_SYMBOL(clk_set_rate);
 141
 142 int clk_set_parent(struct clk *clk, struct clk *parent)
 143 {
 144         unsigned long flags;
 145         int ret = -EINVAL;
 146
 147         if (clk == NULL || IS_ERR(clk) || parent == NULL || IS_ERR(parent))
 148                 return ret;
 149
 150         if (!arch_clock || !arch_clock->clk_set_parent)
 151                 return ret;
 152
 153         spin_lock_irqsave(&clockfw_lock, flags);
 154         if (clk->usecount == 0) {
 155                 ret = arch_clock->clk_set_parent(clk, parent);
 156                 if (ret == 0)
 157                         propagate_rate(clk);
 158         } else
 159                 ret = -EBUSY;
 160         spin_unlock_irqrestore(&clockfw_lock, flags);
 161
 162         return ret;
 163 }
 164 EXPORT_SYMBOL(clk_set_parent);
 165
 166 struct clk *clk_get_parent(struct clk *clk)
 167 {
 168         return clk->parent;
 169 }
 170 EXPORT_SYMBOL(clk_get_parent);
 171
 172 /*
 173  * OMAP specific clock functions shared between omap1 and omap2
 174  */
 175
 176 int __initdata mpurate;
 177
 178 /*
 179  * By default we use the rate set by the bootloader.
 180  * You can override this with mpurate= cmdline option.
 181  */
 182 static int __init omap_clk_setup(char *str)
 183 {
 184         get_option(&str, &mpurate);
 185
 186         if (!mpurate)
 187                 return 1;
 188
 189         if (mpurate < 1000)
 190                 mpurate *= 1000000;
 191
 192         return 1;
 193 }
 194 __setup("mpurate=", omap_clk_setup);
 195
 196 /* Used for clocks that always have same value as the parent clock */
 197 unsigned long followparent_recalc(struct clk *clk)
 198 {
 199         return clk->parent->rate;
 200 }
 201
 202 /*
 203  * Used for clocks that have the same value as the parent clock,
 204  * divided by some factor
 205  */
 206 unsigned long omap_fixed_divisor_recalc(struct clk *clk)
 207 {
 208         WARN_ON(!clk->fixed_div);
 209
 210         return clk->parent->rate / clk->fixed_div;
 211 }
 212
 213 void clk_reparent(struct clk *child, struct clk *parent)
 214 {
 215         list_del_init(&child->sibling);
 216         if (parent)
 217                 list_add(&child->sibling, &parent->children);
 218         child->parent = parent;
 219
 220         /* now do the debugfs renaming to reattach the child
 221            to the proper parent */
 222 }
 223
 224 /* Propagate rate to children */
 225 void propagate_rate(struct clk *tclk)
 226 {
 227         struct clk *clkp;
 228
 229         list_for_each_entry(clkp, &tclk->children, sibling) {
 230                 if (clkp->recalc)
 231                         clkp->rate = clkp->recalc(clkp);
 232                 propagate_rate(clkp);
 233         }
 234 }
 235
 236 static LIST_HEAD(root_clks);
 237
 238 /**
 239  * recalculate_root_clocks - recalculate and propagate all root clocks
 240  *
 241  * Recalculates all root clocks (clocks with no parent), which if the
 242  * clock's .recalc is set correctly, should also propagate their rates.
 243  * Called at init.
 244  */
 245 void recalculate_root_clocks(void)
 246 {
 247         struct clk *clkp;
 248
 249         list_for_each_entry(clkp, &root_clks, sibling) {
 250                 if (clkp->recalc)
 251                         clkp->rate = clkp->recalc(clkp);
 252                 propagate_rate(clkp);
 253         }
 254 }
 255
 256 /**
 257  * clk_preinit - initialize any fields in the struct clk before clk init
 258  * @clk: struct clk * to initialize
 259  *
 260  * Initialize any struct clk fields needed before normal clk initialization
 261  * can run.  No return value.
 262  */
 263 void clk_preinit(struct clk *clk)
 264 {
 265         INIT_LIST_HEAD(&clk->children);
 266 }
 267
 268 int clk_register(struct clk *clk)
 269 {
 270         if (clk == NULL || IS_ERR(clk))
 271                 return -EINVAL;
 272
 273         /*
 274          * trap out already registered clocks
 275          */
 276         if (clk->node.next || clk->node.prev)
 277                 return 0;
 278
 279         mutex_lock(&clocks_mutex);
 280         if (clk->parent)
 281                 list_add(&clk->sibling, &clk->parent->children);
 282         else
 283                 list_add(&clk->sibling, &root_clks);
 284
 285         list_add(&clk->node, &clocks);
 286         if (clk->init)
 287                 clk->init(clk);
 288         mutex_unlock(&clocks_mutex);
 289
 290         return 0;
 291 }
 292 EXPORT_SYMBOL(clk_register);
 293
 294 void clk_unregister(struct clk *clk)
 295 {
 296         if (clk == NULL || IS_ERR(clk))
 297                 return;
 298
 299         mutex_lock(&clocks_mutex);
 300         list_del(&clk->sibling);
 301         list_del(&clk->node);
 302         mutex_unlock(&clocks_mutex);
 303 }
 304 EXPORT_SYMBOL(clk_unregister);
 305
 306 void clk_enable_init_clocks(void)
 307 {
 308         struct clk *clkp;
 309
 310         list_for_each_entry(clkp, &clocks, node) {
 311                 if (clkp->flags & ENABLE_ON_INIT)
 312                         clk_enable(clkp);
 313         }
 314 }
 315
 316 /**
 317  * omap_clk_get_by_name - locate OMAP struct clk by its name
 318  * @name: name of the struct clk to locate
 319  *
 320  * Locate an OMAP struct clk by its name.  Assumes that struct clk
 321  * names are unique.  Returns NULL if not found or a pointer to the
 322  * struct clk if found.
 323  */
 324 struct clk *omap_clk_get_by_name(const char *name)
 325 {
 326         struct clk *c;
 327         struct clk *ret = NULL;
 328
 329         mutex_lock(&clocks_mutex);
 330
 331         list_for_each_entry(c, &clocks, node) {
 332                 if (!strcmp(c->name, name)) {
 333                         ret = c;
 334                         break;
 335                 }
 336         }
 337
 338         mutex_unlock(&clocks_mutex);
 339
 340         return ret;
 341 }
 342
 343 int omap_clk_enable_autoidle_all(void)
 344 {
 345         struct clk *c;
 346         unsigned long flags;
 347
 348         spin_lock_irqsave(&clockfw_lock, flags);
 349
 350         list_for_each_entry(c, &clocks, node)
 351                 if (c->ops->allow_idle)
 352                         c->ops->allow_idle(c);
 353
 354         spin_unlock_irqrestore(&clockfw_lock, flags);
 355
 356         return 0;
 357 }
 358
 359 int omap_clk_disable_autoidle_all(void)
 360 {
 361         struct clk *c;
 362         unsigned long flags;
 363
 364         spin_lock_irqsave(&clockfw_lock, flags);
 365
 366         list_for_each_entry(c, &clocks, node)
 367                 if (c->ops->deny_idle)
 368                         c->ops->deny_idle(c);
 369
 370         spin_unlock_irqrestore(&clockfw_lock, flags);
 371
 372         return 0;
 373 }
 374
 375 /*
 376  * Low level helpers
 377  */
 378 static int clkll_enable_null(struct clk *clk)
 379 {
 380         return 0;
 381 }
 382
 383 static void clkll_disable_null(struct clk *clk)
 384 {
 385 }
 386
 387 const struct clkops clkops_null = {
 388         .enable         = clkll_enable_null,
 389         .disable        = clkll_disable_null,
 390 };
 391
 392 /*
 393  * Dummy clock
 394  *
 395  * Used for clock aliases that are needed on some OMAPs, but not others
 396  */
 397 struct clk dummy_ck = {
 398         .name   = "dummy",
 399         .ops    = &clkops_null,
 400 };
 401
 402 #ifdef CONFIG_CPU_FREQ
 403 void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
 404 {
 405         unsigned long flags;
 406
 407         if (!arch_clock || !arch_clock->clk_init_cpufreq_table)
 408                 return;
 409
 410         spin_lock_irqsave(&clockfw_lock, flags);
 411         arch_clock->clk_init_cpufreq_table(table);
 412         spin_unlock_irqrestore(&clockfw_lock, flags);
 413 }
 414
 415 void clk_exit_cpufreq_table(struct cpufreq_frequency_table **table)
 416 {
 417         unsigned long flags;
 418
 419         if (!arch_clock || !arch_clock->clk_exit_cpufreq_table)
 420                 return;
 421
 422         spin_lock_irqsave(&clockfw_lock, flags);
 423         arch_clock->clk_exit_cpufreq_table(table);
 424         spin_unlock_irqrestore(&clockfw_lock, flags);
 425 }
 426 #endif
 427
 428 /*
 429  *
 430  */
 431
 432 #ifdef CONFIG_OMAP_RESET_CLOCKS
 433 /*
 434  * Disable any unused clocks left on by the bootloader
 435  */
 436 static int __init clk_disable_unused(void)
 437 {
 438         struct clk *ck;
 439         unsigned long flags;
 440
 441         if (!arch_clock || !arch_clock->clk_disable_unused)
 442                 return 0;
 443
 444         pr_info("clock: disabling unused clocks to save power\n");
 445         list_for_each_entry(ck, &clocks, node) {
 446                 if (ck->ops == &clkops_null)
 447                         continue;
 448
 449                 if (ck->usecount > 0 || !ck->enable_reg)
 450                         continue;
 451
 452                 spin_lock_irqsave(&clockfw_lock, flags);
 453                 arch_clock->clk_disable_unused(ck);
 454                 spin_unlock_irqrestore(&clockfw_lock, flags);
 455         }
 456
 457         return 0;
 458 }
 459 late_initcall(clk_disable_unused);
 460 late_initcall(omap_clk_enable_autoidle_all);
 461 #endif
 462
 463 int __init clk_init(struct clk_functions * custom_clocks)
 464 {
 465         if (!custom_clocks) {
 466                 pr_err("No custom clock functions registered\n");
 467                 BUG();
 468         }
 469
 470         arch_clock = custom_clocks;
 471
 472         return 0;
 473 }
 474
 475 #if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
 476 /*
 477  *      debugfs support to trace clock tree hierarchy and attributes
 478  */
 479
 480 #include <linux/debugfs.h>
 481 #include <linux/seq_file.h>
 482
 483 static struct dentry *clk_debugfs_root;
 484
 485 static int clk_dbg_show_summary(struct seq_file *s, void *unused)
 486 {
 487         struct clk *c;
 488         struct clk *pa;
 489
 490         seq_printf(s, "%-30s %-30s %-10s %s\n",
 491                 "clock-name", "parent-name", "rate", "use-count");
 492
 493         list_for_each_entry(c, &clocks, node) {
 494                 pa = c->parent;
 495                 seq_printf(s, "%-30s %-30s %-10lu %d\n",
 496                         c->name, pa ? pa->name : "none", c->rate, c->usecount);
 497         }
 498
 499         return 0;
 500 }
 501
 502 static int clk_dbg_open(struct inode *inode, struct file *file)
 503 {
 504         return single_open(file, clk_dbg_show_summary, inode->i_private);
 505 }
 506
 507 static const struct file_operations debug_clock_fops = {
 508         .open           = clk_dbg_open,
 509         .read           = seq_read,
 510         .llseek         = seq_lseek,
 511         .release        = single_release,
 512 };
 513
 514 static int clk_debugfs_register_one(struct clk *c)
 515 {
 516         int err;
 517         struct dentry *d;
 518         struct clk *pa = c->parent;
 519
 520         d = debugfs_create_dir(c->name, pa ? pa->dent : clk_debugfs_root);
 521         if (!d)
 522                 return -ENOMEM;
 523         c->dent = d;
 524
 525         d = debugfs_create_u8("usecount", S_IRUGO, c->dent, (u8 *)&c->usecount);
 526         if (!d) {
 527                 err = -ENOMEM;
 528                 goto err_out;
 529         }
 530         d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
 531         if (!d) {
 532                 err = -ENOMEM;
 533                 goto err_out;
 534         }
 535         d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
 536         if (!d) {
 537                 err = -ENOMEM;
 538                 goto err_out;
 539         }
 540         return 0;
 541
 542 err_out:
 543         debugfs_remove_recursive(c->dent);
 544         return err;
 545 }
 546
 547 static int clk_debugfs_register(struct clk *c)
 548 {
 549         int err;
 550         struct clk *pa = c->parent;
 551
 552         if (pa && !pa->dent) {
 553                 err = clk_debugfs_register(pa);
 554                 if (err)
 555                         return err;
 556         }
 557
 558         if (!c->dent) {
 559                 err = clk_debugfs_register_one(c);
 560                 if (err)
 561                         return err;
 562         }
 563         return 0;
 564 }
 565
 566 static int __init clk_debugfs_init(void)
 567 {
 568         struct clk *c;
 569         struct dentry *d;
 570         int err;
 571
 572         d = debugfs_create_dir("clock", NULL);
 573         if (!d)
 574                 return -ENOMEM;
 575         clk_debugfs_root = d;
 576
 577         list_for_each_entry(c, &clocks, node) {
 578                 err = clk_debugfs_register(c);
 579                 if (err)
 580                         goto err_out;
 581         }
 582
 583         d = debugfs_create_file("summary", S_IRUGO,
 584                 d, NULL, &debug_clock_fops);
 585         if (!d)
 586                 return -ENOMEM;
 587
 588         return 0;
 589 err_out:
 590         debugfs_remove_recursive(clk_debugfs_root);
 591         return err;
 592 }
 593 late_initcall(clk_debugfs_init);
 594
 595 #endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */