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