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
  27 #include <plat/clock.h>
  28
  29 static LIST_HEAD(clocks);
  30 static DEFINE_MUTEX(clocks_mutex);
  31 static DEFINE_SPINLOCK(clockfw_lock);
  32
  33 static struct clk_functions *arch_clock;
  34
  35 /*-------------------------------------------------------------------------
  36  * Standard clock functions defined in include/linux/clk.h
  37  *-------------------------------------------------------------------------*/
  38
  39 int clk_enable(struct clk *clk)
  40 {
  41         unsigned long flags;
  42         int ret = 0;
  43
  44         if (clk == NULL || IS_ERR(clk))
  45                 return -EINVAL;
  46
  47         spin_lock_irqsave(&clockfw_lock, flags);
  48         if (arch_clock->clk_enable)
  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         spin_lock_irqsave(&clockfw_lock, flags);
  64         if (clk->usecount == 0) {
  65                 printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
  66                        clk->name);
  67                 WARN_ON(1);
  68                 goto out;
  69         }
  70
  71         if (arch_clock->clk_disable)
  72                 arch_clock->clk_disable(clk);
  73
  74 out:
  75         spin_unlock_irqrestore(&clockfw_lock, flags);
  76 }
  77 EXPORT_SYMBOL(clk_disable);
  78
  79 unsigned long clk_get_rate(struct clk *clk)
  80 {
  81         unsigned long flags;
  82         unsigned long ret = 0;
  83
  84         if (clk == NULL || IS_ERR(clk))
  85                 return 0;
  86
  87         spin_lock_irqsave(&clockfw_lock, flags);
  88         ret = clk->rate;
  89         spin_unlock_irqrestore(&clockfw_lock, flags);
  90
  91         return ret;
  92 }
  93 EXPORT_SYMBOL(clk_get_rate);
  94
  95 /*-------------------------------------------------------------------------
  96  * Optional clock functions defined in include/linux/clk.h
  97  *-------------------------------------------------------------------------*/
  98
  99 long clk_round_rate(struct clk *clk, unsigned long rate)
 100 {
 101         unsigned long flags;
 102         long ret = 0;
 103
 104         if (clk == NULL || IS_ERR(clk))
 105                 return ret;
 106
 107         spin_lock_irqsave(&clockfw_lock, flags);
 108         if (arch_clock->clk_round_rate)
 109                 ret = arch_clock->clk_round_rate(clk, rate);
 110         spin_unlock_irqrestore(&clockfw_lock, flags);
 111
 112         return ret;
 113 }
 114 EXPORT_SYMBOL(clk_round_rate);
 115
 116 int clk_set_rate(struct clk *clk, unsigned long rate)
 117 {
 118         unsigned long flags;
 119         int ret = -EINVAL;
 120
 121         if (clk == NULL || IS_ERR(clk))
 122                 return ret;
 123
 124         spin_lock_irqsave(&clockfw_lock, flags);
 125         if (arch_clock->clk_set_rate)
 126                 ret = arch_clock->clk_set_rate(clk, rate);
 127         if (ret == 0) {
 128                 if (clk->recalc)
 129                         clk->rate = clk->recalc(clk);
 130                 propagate_rate(clk);
 131         }
 132         spin_unlock_irqrestore(&clockfw_lock, flags);
 133
 134         return ret;
 135 }
 136 EXPORT_SYMBOL(clk_set_rate);
 137
 138 int clk_set_parent(struct clk *clk, struct clk *parent)
 139 {
 140         unsigned long flags;
 141         int ret = -EINVAL;
 142
 143         if (cpu_is_omap44xx())
 144         /* OMAP4 clk framework not supported yet */
 145                 return 0;
 146         if (clk == NULL || IS_ERR(clk) || parent == NULL || IS_ERR(parent))
 147                 return ret;
 148
 149         spin_lock_irqsave(&clockfw_lock, flags);
 150         if (clk->usecount == 0) {
 151                 if (arch_clock->clk_set_parent)
 152                         ret = arch_clock->clk_set_parent(clk, parent);
 153                 if (ret == 0) {
 154                         if (clk->recalc)
 155                                 clk->rate = clk->recalc(clk);
 156                         propagate_rate(clk);
 157                 }
 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 unsigned 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 void clk_reparent(struct clk *child, struct clk *parent)
 203 {
 204         list_del_init(&child->sibling);
 205         if (parent)
 206                 list_add(&child->sibling, &parent->children);
 207         child->parent = parent;
 208
 209         /* now do the debugfs renaming to reattach the child
 210            to the proper parent */
 211 }
 212
 213 /* Propagate rate to children */
 214 void propagate_rate(struct clk * tclk)
 215 {
 216         struct clk *clkp;
 217
 218         list_for_each_entry(clkp, &tclk->children, sibling) {
 219                 if (clkp->recalc)
 220                         clkp->rate = clkp->recalc(clkp);
 221                 propagate_rate(clkp);
 222         }
 223 }
 224
 225 static LIST_HEAD(root_clks);
 226
 227 /**
 228  * recalculate_root_clocks - recalculate and propagate all root clocks
 229  *
 230  * Recalculates all root clocks (clocks with no parent), which if the
 231  * clock's .recalc is set correctly, should also propagate their rates.
 232  * Called at init.
 233  */
 234 void recalculate_root_clocks(void)
 235 {
 236         struct clk *clkp;
 237
 238         list_for_each_entry(clkp, &root_clks, sibling) {
 239                 if (clkp->recalc)
 240                         clkp->rate = clkp->recalc(clkp);
 241                 propagate_rate(clkp);
 242         }
 243 }
 244
 245 /**
 246  * clk_preinit - initialize any fields in the struct clk before clk init
 247  * @clk: struct clk * to initialize
 248  *
 249  * Initialize any struct clk fields needed before normal clk initialization
 250  * can run.  No return value.
 251  */
 252 void clk_preinit(struct clk *clk)
 253 {
 254         INIT_LIST_HEAD(&clk->children);
 255 }
 256
 257 int clk_register(struct clk *clk)
 258 {
 259         if (clk == NULL || IS_ERR(clk))
 260                 return -EINVAL;
 261
 262         /*
 263          * trap out already registered clocks
 264          */
 265         if (clk->node.next || clk->node.prev)
 266                 return 0;
 267
 268         mutex_lock(&clocks_mutex);
 269         if (clk->parent)
 270                 list_add(&clk->sibling, &clk->parent->children);
 271         else
 272                 list_add(&clk->sibling, &root_clks);
 273
 274         list_add(&clk->node, &clocks);
 275         if (clk->init)
 276                 clk->init(clk);
 277         mutex_unlock(&clocks_mutex);
 278
 279         return 0;
 280 }
 281 EXPORT_SYMBOL(clk_register);
 282
 283 void clk_unregister(struct clk *clk)
 284 {
 285         if (clk == NULL || IS_ERR(clk))
 286                 return;
 287
 288         mutex_lock(&clocks_mutex);
 289         list_del(&clk->sibling);
 290         list_del(&clk->node);
 291         mutex_unlock(&clocks_mutex);
 292 }
 293 EXPORT_SYMBOL(clk_unregister);
 294
 295 void clk_enable_init_clocks(void)
 296 {
 297         struct clk *clkp;
 298
 299         list_for_each_entry(clkp, &clocks, node) {
 300                 if (clkp->flags & ENABLE_ON_INIT)
 301                         clk_enable(clkp);
 302         }
 303 }
 304
 305 /*
 306  * Low level helpers
 307  */
 308 static int clkll_enable_null(struct clk *clk)
 309 {
 310         return 0;
 311 }
 312
 313 static void clkll_disable_null(struct clk *clk)
 314 {
 315 }
 316
 317 const struct clkops clkops_null = {
 318         .enable         = clkll_enable_null,
 319         .disable        = clkll_disable_null,
 320 };
 321
 322 #ifdef CONFIG_CPU_FREQ
 323 void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
 324 {
 325         unsigned long flags;
 326
 327         spin_lock_irqsave(&clockfw_lock, flags);
 328         if (arch_clock->clk_init_cpufreq_table)
 329                 arch_clock->clk_init_cpufreq_table(table);
 330         spin_unlock_irqrestore(&clockfw_lock, flags);
 331 }
 332
 333 void clk_exit_cpufreq_table(struct cpufreq_frequency_table **table)
 334 {
 335         unsigned long flags;
 336
 337         spin_lock_irqsave(&clockfw_lock, flags);
 338         if (arch_clock->clk_exit_cpufreq_table)
 339                 arch_clock->clk_exit_cpufreq_table(table);
 340         spin_unlock_irqrestore(&clockfw_lock, flags);
 341 }
 342 #endif
 343
 344 /*-------------------------------------------------------------------------*/
 345
 346 #ifdef CONFIG_OMAP_RESET_CLOCKS
 347 /*
 348  * Disable any unused clocks left on by the bootloader
 349  */
 350 static int __init clk_disable_unused(void)
 351 {
 352         struct clk *ck;
 353         unsigned long flags;
 354
 355         list_for_each_entry(ck, &clocks, node) {
 356                 if (ck->ops == &clkops_null)
 357                         continue;
 358
 359                 if (ck->usecount > 0 || ck->enable_reg == 0)
 360                         continue;
 361
 362                 spin_lock_irqsave(&clockfw_lock, flags);
 363                 if (arch_clock->clk_disable_unused)
 364                         arch_clock->clk_disable_unused(ck);
 365                 spin_unlock_irqrestore(&clockfw_lock, flags);
 366         }
 367
 368         return 0;
 369 }
 370 late_initcall(clk_disable_unused);
 371 #endif
 372
 373 int __init clk_init(struct clk_functions * custom_clocks)
 374 {
 375         if (!custom_clocks) {
 376                 printk(KERN_ERR "No custom clock functions registered\n");
 377                 BUG();
 378         }
 379
 380         arch_clock = custom_clocks;
 381
 382         return 0;
 383 }
 384
 385 #if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
 386 /*
 387  *      debugfs support to trace clock tree hierarchy and attributes
 388  */
 389 static struct dentry *clk_debugfs_root;
 390
 391 static int clk_debugfs_register_one(struct clk *c)
 392 {
 393         int err;
 394         struct dentry *d, *child, *child_tmp;
 395         struct clk *pa = c->parent;
 396         char s[255];
 397         char *p = s;
 398
 399         p += sprintf(p, "%s", c->name);
 400         if (c->id != 0)
 401                 sprintf(p, ":%d", c->id);
 402         d = debugfs_create_dir(s, pa ? pa->dent : clk_debugfs_root);
 403         if (!d)
 404                 return -ENOMEM;
 405         c->dent = d;
 406
 407         d = debugfs_create_u8("usecount", S_IRUGO, c->dent, (u8 *)&c->usecount);
 408         if (!d) {
 409                 err = -ENOMEM;
 410                 goto err_out;
 411         }
 412         d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
 413         if (!d) {
 414                 err = -ENOMEM;
 415                 goto err_out;
 416         }
 417         d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
 418         if (!d) {
 419                 err = -ENOMEM;
 420                 goto err_out;
 421         }
 422         return 0;
 423
 424 err_out:
 425         d = c->dent;
 426         list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
 427                 debugfs_remove(child);
 428         debugfs_remove(c->dent);
 429         return err;
 430 }
 431
 432 static int clk_debugfs_register(struct clk *c)
 433 {
 434         int err;
 435         struct clk *pa = c->parent;
 436
 437         if (pa && !pa->dent) {
 438                 err = clk_debugfs_register(pa);
 439                 if (err)
 440                         return err;
 441         }
 442
 443         if (!c->dent) {
 444                 err = clk_debugfs_register_one(c);
 445                 if (err)
 446                         return err;
 447         }
 448         return 0;
 449 }
 450
 451 static int __init clk_debugfs_init(void)
 452 {
 453         struct clk *c;
 454         struct dentry *d;
 455         int err;
 456
 457         d = debugfs_create_dir("clock", NULL);
 458         if (!d)
 459                 return -ENOMEM;
 460         clk_debugfs_root = d;
 461
 462         list_for_each_entry(c, &clocks, node) {
 463                 err = clk_debugfs_register(c);
 464                 if (err)
 465                         goto err_out;
 466         }
 467         return 0;
 468 err_out:
 469         debugfs_remove_recursive(clk_debugfs_root);
 470         return err;
 471 }
 472 late_initcall(clk_debugfs_init);
 473
 474 #endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */