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 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  * Low level helpers
 318  */
 319 static int clkll_enable_null(struct clk *clk)
 320 {
 321         return 0;
 322 }
 323
 324 static void clkll_disable_null(struct clk *clk)
 325 {
 326 }
 327
 328 const struct clkops clkops_null = {
 329         .enable         = clkll_enable_null,
 330         .disable        = clkll_disable_null,
 331 };
 332
 333 #ifdef CONFIG_CPU_FREQ
 334 void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
 335 {
 336         unsigned long flags;
 337
 338         spin_lock_irqsave(&clockfw_lock, flags);
 339         if (arch_clock->clk_init_cpufreq_table)
 340                 arch_clock->clk_init_cpufreq_table(table);
 341         spin_unlock_irqrestore(&clockfw_lock, flags);
 342 }
 343
 344 void clk_exit_cpufreq_table(struct cpufreq_frequency_table **table)
 345 {
 346         unsigned long flags;
 347
 348         spin_lock_irqsave(&clockfw_lock, flags);
 349         if (arch_clock->clk_exit_cpufreq_table)
 350                 arch_clock->clk_exit_cpufreq_table(table);
 351         spin_unlock_irqrestore(&clockfw_lock, flags);
 352 }
 353 #endif
 354
 355 /*-------------------------------------------------------------------------*/
 356
 357 #ifdef CONFIG_OMAP_RESET_CLOCKS
 358 /*
 359  * Disable any unused clocks left on by the bootloader
 360  */
 361 static int __init clk_disable_unused(void)
 362 {
 363         struct clk *ck;
 364         unsigned long flags;
 365
 366         list_for_each_entry(ck, &clocks, node) {
 367                 if (ck->ops == &clkops_null)
 368                         continue;
 369
 370                 if (ck->usecount > 0 || ck->enable_reg == 0)
 371                         continue;
 372
 373                 spin_lock_irqsave(&clockfw_lock, flags);
 374                 if (arch_clock->clk_disable_unused)
 375                         arch_clock->clk_disable_unused(ck);
 376                 spin_unlock_irqrestore(&clockfw_lock, flags);
 377         }
 378
 379         return 0;
 380 }
 381 late_initcall(clk_disable_unused);
 382 #endif
 383
 384 int __init clk_init(struct clk_functions * custom_clocks)
 385 {
 386         if (!custom_clocks) {
 387                 printk(KERN_ERR "No custom clock functions registered\n");
 388                 BUG();
 389         }
 390
 391         arch_clock = custom_clocks;
 392
 393         return 0;
 394 }
 395
 396 #if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
 397 /*
 398  *      debugfs support to trace clock tree hierarchy and attributes
 399  */
 400 static struct dentry *clk_debugfs_root;
 401
 402 static int clk_debugfs_register_one(struct clk *c)
 403 {
 404         int err;
 405         struct dentry *d, *child, *child_tmp;
 406         struct clk *pa = c->parent;
 407         char s[255];
 408         char *p = s;
 409
 410         p += sprintf(p, "%s", c->name);
 411         d = debugfs_create_dir(s, pa ? pa->dent : clk_debugfs_root);
 412         if (!d)
 413                 return -ENOMEM;
 414         c->dent = d;
 415
 416         d = debugfs_create_u8("usecount", S_IRUGO, c->dent, (u8 *)&c->usecount);
 417         if (!d) {
 418                 err = -ENOMEM;
 419                 goto err_out;
 420         }
 421         d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
 422         if (!d) {
 423                 err = -ENOMEM;
 424                 goto err_out;
 425         }
 426         d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
 427         if (!d) {
 428                 err = -ENOMEM;
 429                 goto err_out;
 430         }
 431         return 0;
 432
 433 err_out:
 434         d = c->dent;
 435         list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
 436                 debugfs_remove(child);
 437         debugfs_remove(c->dent);
 438         return err;
 439 }
 440
 441 static int clk_debugfs_register(struct clk *c)
 442 {
 443         int err;
 444         struct clk *pa = c->parent;
 445
 446         if (pa && !pa->dent) {
 447                 err = clk_debugfs_register(pa);
 448                 if (err)
 449                         return err;
 450         }
 451
 452         if (!c->dent) {
 453                 err = clk_debugfs_register_one(c);
 454                 if (err)
 455                         return err;
 456         }
 457         return 0;
 458 }
 459
 460 static int __init clk_debugfs_init(void)
 461 {
 462         struct clk *c;
 463         struct dentry *d;
 464         int err;
 465
 466         d = debugfs_create_dir("clock", NULL);
 467         if (!d)
 468                 return -ENOMEM;
 469         clk_debugfs_root = d;
 470
 471         list_for_each_entry(c, &clocks, node) {
 472                 err = clk_debugfs_register(c);
 473                 if (err)
 474                         goto err_out;
 475         }
 476         return 0;
 477 err_out:
 478         debugfs_remove_recursive(clk_debugfs_root);
 479         return err;
 480 }
 481 late_initcall(clk_debugfs_init);
 482
 483 #endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */