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