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   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 <mach/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 int clk_get_usecount(struct clk *clk)
  80 {
  81         unsigned long flags;
  82         int ret = 0;
  83
  84         if (clk == NULL || IS_ERR(clk))
  85                 return 0;
  86
  87         spin_lock_irqsave(&clockfw_lock, flags);
  88         ret = clk->usecount;
  89         spin_unlock_irqrestore(&clockfw_lock, flags);
  90
  91         return ret;
  92 }
  93 EXPORT_SYMBOL(clk_get_usecount);
  94
  95 unsigned long clk_get_rate(struct clk *clk)
  96 {
  97         unsigned long flags;
  98         unsigned long ret = 0;
  99
 100         if (clk == NULL || IS_ERR(clk))
 101                 return 0;
 102
 103         spin_lock_irqsave(&clockfw_lock, flags);
 104         ret = clk->rate;
 105         spin_unlock_irqrestore(&clockfw_lock, flags);
 106
 107         return ret;
 108 }
 109 EXPORT_SYMBOL(clk_get_rate);
 110
 111 /*-------------------------------------------------------------------------
 112  * Optional clock functions defined in include/linux/clk.h
 113  *-------------------------------------------------------------------------*/
 114
 115 long clk_round_rate(struct clk *clk, unsigned long rate)
 116 {
 117         unsigned long flags;
 118         long ret = 0;
 119
 120         if (clk == NULL || IS_ERR(clk))
 121                 return ret;
 122
 123         spin_lock_irqsave(&clockfw_lock, flags);
 124         if (arch_clock->clk_round_rate)
 125                 ret = arch_clock->clk_round_rate(clk, rate);
 126         spin_unlock_irqrestore(&clockfw_lock, flags);
 127
 128         return ret;
 129 }
 130 EXPORT_SYMBOL(clk_round_rate);
 131
 132 int clk_set_rate(struct clk *clk, unsigned long rate)
 133 {
 134         unsigned long flags;
 135         int ret = -EINVAL;
 136
 137         if (clk == NULL || IS_ERR(clk))
 138                 return ret;
 139
 140         spin_lock_irqsave(&clockfw_lock, flags);
 141         if (arch_clock->clk_set_rate)
 142                 ret = arch_clock->clk_set_rate(clk, rate);
 143         if (ret == 0) {
 144                 if (clk->recalc)
 145                         clk->recalc(clk);
 146                 if (clk->flags & RATE_PROPAGATES)
 147                         propagate_rate(clk);
 148         }
 149         spin_unlock_irqrestore(&clockfw_lock, flags);
 150
 151         return ret;
 152 }
 153 EXPORT_SYMBOL(clk_set_rate);
 154
 155 int clk_set_parent(struct clk *clk, struct clk *parent)
 156 {
 157         unsigned long flags;
 158         int ret = -EINVAL;
 159
 160         if (clk == NULL || IS_ERR(clk) || parent == NULL || IS_ERR(parent))
 161                 return ret;
 162
 163         spin_lock_irqsave(&clockfw_lock, flags);
 164         if (arch_clock->clk_set_parent)
 165                 ret = arch_clock->clk_set_parent(clk, parent);
 166         if (ret == 0) {
 167                 if (clk->recalc)
 168                         clk->recalc(clk);
 169                 if (clk->flags & RATE_PROPAGATES)
 170                         propagate_rate(clk);
 171         }
 172         spin_unlock_irqrestore(&clockfw_lock, flags);
 173
 174         return ret;
 175 }
 176 EXPORT_SYMBOL(clk_set_parent);
 177
 178 struct clk *clk_get_parent(struct clk *clk)
 179 {
 180         return clk->parent;
 181 }
 182 EXPORT_SYMBOL(clk_get_parent);
 183
 184 /*-------------------------------------------------------------------------
 185  * OMAP specific clock functions shared between omap1 and omap2
 186  *-------------------------------------------------------------------------*/
 187
 188 unsigned int __initdata mpurate;
 189
 190 /*
 191  * By default we use the rate set by the bootloader.
 192  * You can override this with mpurate= cmdline option.
 193  */
 194 static int __init omap_clk_setup(char *str)
 195 {
 196         get_option(&str, &mpurate);
 197
 198         if (!mpurate)
 199                 return 1;
 200
 201         if (mpurate < 1000)
 202                 mpurate *= 1000000;
 203
 204         return 1;
 205 }
 206 __setup("mpurate=", omap_clk_setup);
 207
 208 /* Used for clocks that always have same value as the parent clock */
 209 void followparent_recalc(struct clk *clk)
 210 {
 211         if (clk == NULL || IS_ERR(clk))
 212                 return;
 213
 214         clk->rate = clk->parent->rate;
 215 }
 216
 217 /* Propagate rate to children */
 218 void propagate_rate(struct clk * tclk)
 219 {
 220         struct clk *clkp;
 221
 222         if (tclk == NULL || IS_ERR(tclk))
 223                 return;
 224
 225         list_for_each_entry(clkp, &clocks, node) {
 226                 if (likely(clkp->parent != tclk))
 227                         continue;
 228                 if (clkp->recalc)
 229                         clkp->recalc(clkp);
 230                 if (clkp->flags & RATE_PROPAGATES)
 231                         propagate_rate(clkp);
 232         }
 233 }
 234
 235 /**
 236  * recalculate_root_clocks - recalculate and propagate all root clocks
 237  *
 238  * Recalculates all root clocks (clocks with no parent), which if the
 239  * clock's .recalc is set correctly, should also propagate their rates.
 240  * Called at init.
 241  */
 242 void recalculate_root_clocks(void)
 243 {
 244         struct clk *clkp;
 245
 246         list_for_each_entry(clkp, &clocks, node) {
 247                 if (!clkp->parent) {
 248                         if (clkp->recalc)
 249                                 clkp->recalc(clkp);
 250                         if (clkp->flags & RATE_PROPAGATES)
 251                                 propagate_rate(clkp);
 252                 }
 253         }
 254 }
 255
 256 int clk_register(struct clk *clk)
 257 {
 258         if (clk == NULL || IS_ERR(clk))
 259                 return -EINVAL;
 260
 261         /*
 262          * trap out already registered clocks
 263          */
 264         if (clk->node.next || clk->node.prev)
 265                 return 0;
 266
 267         mutex_lock(&clocks_mutex);
 268         list_add(&clk->node, &clocks);
 269         if (clk->init)
 270                 clk->init(clk);
 271         mutex_unlock(&clocks_mutex);
 272
 273         return 0;
 274 }
 275 EXPORT_SYMBOL(clk_register);
 276
 277 void clk_unregister(struct clk *clk)
 278 {
 279         if (clk == NULL || IS_ERR(clk))
 280                 return;
 281
 282         mutex_lock(&clocks_mutex);
 283         list_del(&clk->node);
 284         mutex_unlock(&clocks_mutex);
 285 }
 286 EXPORT_SYMBOL(clk_unregister);
 287
 288 void clk_enable_init_clocks(void)
 289 {
 290         struct clk *clkp;
 291
 292         list_for_each_entry(clkp, &clocks, node) {
 293                 if (clkp->flags & ENABLE_ON_INIT)
 294                         clk_enable(clkp);
 295         }
 296 }
 297 EXPORT_SYMBOL(clk_enable_init_clocks);
 298
 299 /*
 300  * Low level helpers
 301  */
 302 static int clkll_enable_null(struct clk *clk)
 303 {
 304         return 0;
 305 }
 306
 307 static void clkll_disable_null(struct clk *clk)
 308 {
 309 }
 310
 311 const struct clkops clkops_null = {
 312         .enable         = clkll_enable_null,
 313         .disable        = clkll_disable_null,
 314 };
 315
 316 #ifdef CONFIG_CPU_FREQ
 317 void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
 318 {
 319         unsigned long flags;
 320
 321         spin_lock_irqsave(&clockfw_lock, flags);
 322         if (arch_clock->clk_init_cpufreq_table)
 323                 arch_clock->clk_init_cpufreq_table(table);
 324         spin_unlock_irqrestore(&clockfw_lock, flags);
 325 }
 326 EXPORT_SYMBOL(clk_init_cpufreq_table);
 327 #endif
 328
 329 /*-------------------------------------------------------------------------*/
 330
 331 #ifdef CONFIG_OMAP_RESET_CLOCKS
 332 /*
 333  * Disable any unused clocks left on by the bootloader
 334  */
 335 static int __init clk_disable_unused(void)
 336 {
 337         struct clk *ck;
 338         unsigned long flags;
 339
 340         list_for_each_entry(ck, &clocks, node) {
 341                 if (ck->ops == &clkops_null)
 342                         continue;
 343
 344                 if (ck->usecount > 0 || ck->enable_reg == 0)
 345                         continue;
 346
 347                 spin_lock_irqsave(&clockfw_lock, flags);
 348                 if (arch_clock->clk_disable_unused)
 349                         arch_clock->clk_disable_unused(ck);
 350                 spin_unlock_irqrestore(&clockfw_lock, flags);
 351         }
 352
 353         return 0;
 354 }
 355 late_initcall(clk_disable_unused);
 356 #endif
 357
 358 int __init clk_init(struct clk_functions * custom_clocks)
 359 {
 360         if (!custom_clocks) {
 361                 printk(KERN_ERR "No custom clock functions registered\n");
 362                 BUG();
 363         }
 364
 365         arch_clock = custom_clocks;
 366
 367         return 0;
 368 }
 369
 370 #if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
 371 /*
 372  *      debugfs support to trace clock tree hierarchy and attributes
 373  */
 374 static struct dentry *clk_debugfs_root;
 375
 376 static int clk_debugfs_register_one(struct clk *c)
 377 {
 378         int err;
 379         struct dentry *d, *child;
 380         struct clk *pa = c->parent;
 381         char s[255];
 382         char *p = s;
 383
 384         p += sprintf(p, "%s", c->name);
 385         if (c->id != 0)
 386                 sprintf(p, ":%d", c->id);
 387         d = debugfs_create_dir(s, pa ? pa->dent : clk_debugfs_root);
 388         if (!d)
 389                 return -ENOMEM;
 390         c->dent = d;
 391
 392         d = debugfs_create_u8("usecount", S_IRUGO, c->dent, (u8 *)&c->usecount);
 393         if (!d) {
 394                 err = -ENOMEM;
 395                 goto err_out;
 396         }
 397         d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
 398         if (!d) {
 399                 err = -ENOMEM;
 400                 goto err_out;
 401         }
 402         d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
 403         if (!d) {
 404                 err = -ENOMEM;
 405                 goto err_out;
 406         }
 407         return 0;
 408
 409 err_out:
 410         d = c->dent;
 411         list_for_each_entry(child, &d->d_subdirs, d_u.d_child)
 412                 debugfs_remove(child);
 413         debugfs_remove(c->dent);
 414         return err;
 415 }
 416
 417 static int clk_debugfs_register(struct clk *c)
 418 {
 419         int err;
 420         struct clk *pa = c->parent;
 421
 422         if (pa && !pa->dent) {
 423                 err = clk_debugfs_register(pa);
 424                 if (err)
 425                         return err;
 426         }
 427
 428         if (!c->dent) {
 429                 err = clk_debugfs_register_one(c);
 430                 if (err)
 431                         return err;
 432         }
 433         return 0;
 434 }
 435
 436 static int __init clk_debugfs_init(void)
 437 {
 438         struct clk *c;
 439         struct dentry *d;
 440         int err;
 441
 442         d = debugfs_create_dir("clock", NULL);
 443         if (!d)
 444                 return -ENOMEM;
 445         clk_debugfs_root = d;
 446
 447         list_for_each_entry(c, &clocks, node) {
 448                 err = clk_debugfs_register(c);
 449                 if (err)
 450                         goto err_out;
 451         }
 452         return 0;
 453 err_out:
 454         debugfs_remove(clk_debugfs_root); /* REVISIT: Cleanup correctly */
 455         return err;
 456 }
 457 late_initcall(clk_debugfs_init);
 458
 459 #endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */