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 /* This functions is moved to arch/arm/common/clkdev.c. For OMAP4 since
  40  * clock framework is not up , it is defined here to avoid rework in
  41  * every driver. Also dummy prcm reset function is added */
  42
  43 /* Dummy hooks only for OMAP4.For rest OMAPs, common clkdev is used */
  44 #if defined(CONFIG_ARCH_OMAP4)
  45 struct clk *clk_get(struct device *dev, const char *id)
  46 {
  47         return NULL;
  48 }
  49 EXPORT_SYMBOL(clk_get);
  50
  51 void clk_put(struct clk *clk)
  52 {
  53 }
  54 EXPORT_SYMBOL(clk_put);
  55
  56 void omap2_clk_prepare_for_reboot(void)
  57 {
  58 }
  59 EXPORT_SYMBOL(omap2_clk_prepare_for_reboot);
  60 #endif
  61 int clk_enable(struct clk *clk)
  62 {
  63         unsigned long flags;
  64         int ret = 0;
  65         if (cpu_is_omap44xx())
  66                 /* OMAP4 clk framework not supported yet */
  67                 return 0;
  68
  69         if (clk == NULL || IS_ERR(clk))
  70                 return -EINVAL;
  71
  72         spin_lock_irqsave(&clockfw_lock, flags);
  73         if (arch_clock->clk_enable)
  74                 ret = arch_clock->clk_enable(clk);
  75         spin_unlock_irqrestore(&clockfw_lock, flags);
  76
  77         return ret;
  78 }
  79 EXPORT_SYMBOL(clk_enable);
  80
  81 void clk_disable(struct clk *clk)
  82 {
  83         unsigned long flags;
  84
  85         if (clk == NULL || IS_ERR(clk))
  86                 return;
  87
  88         spin_lock_irqsave(&clockfw_lock, flags);
  89         if (clk->usecount == 0) {
  90                 printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
  91                        clk->name);
  92                 WARN_ON(1);
  93                 goto out;
  94         }
  95
  96         if (arch_clock->clk_disable)
  97                 arch_clock->clk_disable(clk);
  98
  99 out:
 100         spin_unlock_irqrestore(&clockfw_lock, flags);
 101 }
 102 EXPORT_SYMBOL(clk_disable);
 103
 104 unsigned long clk_get_rate(struct clk *clk)
 105 {
 106         unsigned long flags;
 107         unsigned long ret = 0;
 108
 109         if (clk == NULL || IS_ERR(clk))
 110                 return 0;
 111
 112         spin_lock_irqsave(&clockfw_lock, flags);
 113         ret = clk->rate;
 114         spin_unlock_irqrestore(&clockfw_lock, flags);
 115
 116         return ret;
 117 }
 118 EXPORT_SYMBOL(clk_get_rate);
 119
 120 /*-------------------------------------------------------------------------
 121  * Optional clock functions defined in include/linux/clk.h
 122  *-------------------------------------------------------------------------*/
 123
 124 long clk_round_rate(struct clk *clk, unsigned long rate)
 125 {
 126         unsigned long flags;
 127         long ret = 0;
 128
 129         if (clk == NULL || IS_ERR(clk))
 130                 return ret;
 131
 132         spin_lock_irqsave(&clockfw_lock, flags);
 133         if (arch_clock->clk_round_rate)
 134                 ret = arch_clock->clk_round_rate(clk, rate);
 135         spin_unlock_irqrestore(&clockfw_lock, flags);
 136
 137         return ret;
 138 }
 139 EXPORT_SYMBOL(clk_round_rate);
 140
 141 int clk_set_rate(struct clk *clk, unsigned long rate)
 142 {
 143         unsigned long flags;
 144         int ret = -EINVAL;
 145
 146         if (clk == NULL || IS_ERR(clk))
 147                 return ret;
 148
 149         spin_lock_irqsave(&clockfw_lock, flags);
 150         if (arch_clock->clk_set_rate)
 151                 ret = arch_clock->clk_set_rate(clk, rate);
 152         if (ret == 0) {
 153                 if (clk->recalc)
 154                         clk->rate = clk->recalc(clk);
 155                 propagate_rate(clk);
 156         }
 157         spin_unlock_irqrestore(&clockfw_lock, flags);
 158
 159         return ret;
 160 }
 161 EXPORT_SYMBOL(clk_set_rate);
 162
 163 int clk_set_parent(struct clk *clk, struct clk *parent)
 164 {
 165         unsigned long flags;
 166         int ret = -EINVAL;
 167
 168         if (cpu_is_omap44xx())
 169         /* OMAP4 clk framework not supported yet */
 170                 return 0;
 171         if (clk == NULL || IS_ERR(clk) || parent == NULL || IS_ERR(parent))
 172                 return ret;
 173
 174         spin_lock_irqsave(&clockfw_lock, flags);
 175         if (clk->usecount == 0) {
 176                 if (arch_clock->clk_set_parent)
 177                         ret = arch_clock->clk_set_parent(clk, parent);
 178                 if (ret == 0) {
 179                         if (clk->recalc)
 180                                 clk->rate = clk->recalc(clk);
 181                         propagate_rate(clk);
 182                 }
 183         } else
 184                 ret = -EBUSY;
 185         spin_unlock_irqrestore(&clockfw_lock, flags);
 186
 187         return ret;
 188 }
 189 EXPORT_SYMBOL(clk_set_parent);
 190
 191 struct clk *clk_get_parent(struct clk *clk)
 192 {
 193         return clk->parent;
 194 }
 195 EXPORT_SYMBOL(clk_get_parent);
 196
 197 /*-------------------------------------------------------------------------
 198  * OMAP specific clock functions shared between omap1 and omap2
 199  *-------------------------------------------------------------------------*/
 200
 201 unsigned int __initdata mpurate;
 202
 203 /*
 204  * By default we use the rate set by the bootloader.
 205  * You can override this with mpurate= cmdline option.
 206  */
 207 static int __init omap_clk_setup(char *str)
 208 {
 209         get_option(&str, &mpurate);
 210
 211         if (!mpurate)
 212                 return 1;
 213
 214         if (mpurate < 1000)
 215                 mpurate *= 1000000;
 216
 217         return 1;
 218 }
 219 __setup("mpurate=", omap_clk_setup);
 220
 221 /* Used for clocks that always have same value as the parent clock */
 222 unsigned long followparent_recalc(struct clk *clk)
 223 {
 224         return clk->parent->rate;
 225 }
 226
 227 void clk_reparent(struct clk *child, struct clk *parent)
 228 {
 229         list_del_init(&child->sibling);
 230         if (parent)
 231                 list_add(&child->sibling, &parent->children);
 232         child->parent = parent;
 233
 234         /* now do the debugfs renaming to reattach the child
 235            to the proper parent */
 236 }
 237
 238 /* Propagate rate to children */
 239 void propagate_rate(struct clk * tclk)
 240 {
 241         struct clk *clkp;
 242
 243         list_for_each_entry(clkp, &tclk->children, sibling) {
 244                 if (clkp->recalc)
 245                         clkp->rate = clkp->recalc(clkp);
 246                 propagate_rate(clkp);
 247         }
 248 }
 249
 250 static LIST_HEAD(root_clks);
 251
 252 /**
 253  * recalculate_root_clocks - recalculate and propagate all root clocks
 254  *
 255  * Recalculates all root clocks (clocks with no parent), which if the
 256  * clock's .recalc is set correctly, should also propagate their rates.
 257  * Called at init.
 258  */
 259 void recalculate_root_clocks(void)
 260 {
 261         struct clk *clkp;
 262
 263         list_for_each_entry(clkp, &root_clks, sibling) {
 264                 if (clkp->recalc)
 265                         clkp->rate = clkp->recalc(clkp);
 266                 propagate_rate(clkp);
 267         }
 268 }
 269
 270 /**
 271  * clk_preinit - initialize any fields in the struct clk before clk init
 272  * @clk: struct clk * to initialize
 273  *
 274  * Initialize any struct clk fields needed before normal clk initialization
 275  * can run.  No return value.
 276  */
 277 void clk_preinit(struct clk *clk)
 278 {
 279         INIT_LIST_HEAD(&clk->children);
 280 }
 281
 282 int clk_register(struct clk *clk)
 283 {
 284         if (clk == NULL || IS_ERR(clk))
 285                 return -EINVAL;
 286
 287         /*
 288          * trap out already registered clocks
 289          */
 290         if (clk->node.next || clk->node.prev)
 291                 return 0;
 292
 293         mutex_lock(&clocks_mutex);
 294         if (clk->parent)
 295                 list_add(&clk->sibling, &clk->parent->children);
 296         else
 297                 list_add(&clk->sibling, &root_clks);
 298
 299         list_add(&clk->node, &clocks);
 300         if (clk->init)
 301                 clk->init(clk);
 302         mutex_unlock(&clocks_mutex);
 303
 304         return 0;
 305 }
 306 EXPORT_SYMBOL(clk_register);
 307
 308 void clk_unregister(struct clk *clk)
 309 {
 310         if (clk == NULL || IS_ERR(clk))
 311                 return;
 312
 313         mutex_lock(&clocks_mutex);
 314         list_del(&clk->sibling);
 315         list_del(&clk->node);
 316         mutex_unlock(&clocks_mutex);
 317 }
 318 EXPORT_SYMBOL(clk_unregister);
 319
 320 void clk_enable_init_clocks(void)
 321 {
 322         struct clk *clkp;
 323
 324         list_for_each_entry(clkp, &clocks, node) {
 325                 if (clkp->flags & ENABLE_ON_INIT)
 326                         clk_enable(clkp);
 327         }
 328 }
 329 EXPORT_SYMBOL(clk_enable_init_clocks);
 330
 331 /*
 332  * Low level helpers
 333  */
 334 static int clkll_enable_null(struct clk *clk)
 335 {
 336         return 0;
 337 }
 338
 339 static void clkll_disable_null(struct clk *clk)
 340 {
 341 }
 342
 343 const struct clkops clkops_null = {
 344         .enable         = clkll_enable_null,
 345         .disable        = clkll_disable_null,
 346 };
 347
 348 #ifdef CONFIG_CPU_FREQ
 349 void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
 350 {
 351         unsigned long flags;
 352
 353         spin_lock_irqsave(&clockfw_lock, flags);
 354         if (arch_clock->clk_init_cpufreq_table)
 355                 arch_clock->clk_init_cpufreq_table(table);
 356         spin_unlock_irqrestore(&clockfw_lock, flags);
 357 }
 358 EXPORT_SYMBOL(clk_init_cpufreq_table);
 359 #endif
 360
 361 /*-------------------------------------------------------------------------*/
 362
 363 #ifdef CONFIG_OMAP_RESET_CLOCKS
 364 /*
 365  * Disable any unused clocks left on by the bootloader
 366  */
 367 static int __init clk_disable_unused(void)
 368 {
 369         struct clk *ck;
 370         unsigned long flags;
 371
 372         list_for_each_entry(ck, &clocks, node) {
 373                 if (ck->ops == &clkops_null)
 374                         continue;
 375
 376                 if (ck->usecount > 0 || ck->enable_reg == 0)
 377                         continue;
 378
 379                 spin_lock_irqsave(&clockfw_lock, flags);
 380                 if (arch_clock->clk_disable_unused)
 381                         arch_clock->clk_disable_unused(ck);
 382                 spin_unlock_irqrestore(&clockfw_lock, flags);
 383         }
 384
 385         return 0;
 386 }
 387 late_initcall(clk_disable_unused);
 388 #endif
 389
 390 int __init clk_init(struct clk_functions * custom_clocks)
 391 {
 392         if (!custom_clocks) {
 393                 printk(KERN_ERR "No custom clock functions registered\n");
 394                 BUG();
 395         }
 396
 397         arch_clock = custom_clocks;
 398
 399         return 0;
 400 }
 401
 402 #if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
 403 /*
 404  *      debugfs support to trace clock tree hierarchy and attributes
 405  */
 406 static struct dentry *clk_debugfs_root;
 407
 408 static int clk_debugfs_register_one(struct clk *c)
 409 {
 410         int err;
 411         struct dentry *d, *child;
 412         struct clk *pa = c->parent;
 413         char s[255];
 414         char *p = s;
 415
 416         p += sprintf(p, "%s", c->name);
 417         if (c->id != 0)
 418                 sprintf(p, ":%d", c->id);
 419         d = debugfs_create_dir(s, pa ? pa->dent : clk_debugfs_root);
 420         if (!d)
 421                 return -ENOMEM;
 422         c->dent = d;
 423
 424         d = debugfs_create_u8("usecount", S_IRUGO, c->dent, (u8 *)&c->usecount);
 425         if (!d) {
 426                 err = -ENOMEM;
 427                 goto err_out;
 428         }
 429         d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
 430         if (!d) {
 431                 err = -ENOMEM;
 432                 goto err_out;
 433         }
 434         d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
 435         if (!d) {
 436                 err = -ENOMEM;
 437                 goto err_out;
 438         }
 439         return 0;
 440
 441 err_out:
 442         d = c->dent;
 443         list_for_each_entry(child, &d->d_subdirs, d_u.d_child)
 444                 debugfs_remove(child);
 445         debugfs_remove(c->dent);
 446         return err;
 447 }
 448
 449 static int clk_debugfs_register(struct clk *c)
 450 {
 451         int err;
 452         struct clk *pa = c->parent;
 453
 454         if (pa && !pa->dent) {
 455                 err = clk_debugfs_register(pa);
 456                 if (err)
 457                         return err;
 458         }
 459
 460         if (!c->dent) {
 461                 err = clk_debugfs_register_one(c);
 462                 if (err)
 463                         return err;
 464         }
 465         return 0;
 466 }
 467
 468 static int __init clk_debugfs_init(void)
 469 {
 470         struct clk *c;
 471         struct dentry *d;
 472         int err;
 473
 474         d = debugfs_create_dir("clock", NULL);
 475         if (!d)
 476                 return -ENOMEM;
 477         clk_debugfs_root = d;
 478
 479         list_for_each_entry(c, &clocks, node) {
 480                 err = clk_debugfs_register(c);
 481                 if (err)
 482                         goto err_out;
 483         }
 484         return 0;
 485 err_out:
 486         debugfs_remove_recursive(clk_debugfs_root);
 487         return err;
 488 }
 489 late_initcall(clk_debugfs_init);
 490
 491 #endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */