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 <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 /* 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
  61 void omap_prcm_arch_reset(char mode)
  62 {
  63 }
  64 EXPORT_SYMBOL(omap_prcm_arch_reset);
  65 #endif
  66 int clk_enable(struct clk *clk)
  67 {
  68         unsigned long flags;
  69         int ret = 0;
  70         if (cpu_is_omap44xx())
  71                 /* OMAP4 clk framework not supported yet */
  72                 return 0;
  73
  74         if (clk == NULL || IS_ERR(clk))
  75                 return -EINVAL;
  76
  77         spin_lock_irqsave(&clockfw_lock, flags);
  78         if (arch_clock->clk_enable)
  79                 ret = arch_clock->clk_enable(clk);
  80         spin_unlock_irqrestore(&clockfw_lock, flags);
  81
  82         return ret;
  83 }
  84 EXPORT_SYMBOL(clk_enable);
  85
  86 void clk_disable(struct clk *clk)
  87 {
  88         unsigned long flags;
  89
  90         if (clk == NULL || IS_ERR(clk))
  91                 return;
  92
  93         spin_lock_irqsave(&clockfw_lock, flags);
  94         if (clk->usecount == 0) {
  95                 printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
  96                        clk->name);
  97                 WARN_ON(1);
  98                 goto out;
  99         }
 100
 101         if (arch_clock->clk_disable)
 102                 arch_clock->clk_disable(clk);
 103
 104 out:
 105         spin_unlock_irqrestore(&clockfw_lock, flags);
 106 }
 107 EXPORT_SYMBOL(clk_disable);
 108
 109 unsigned long clk_get_rate(struct clk *clk)
 110 {
 111         unsigned long flags;
 112         unsigned long ret = 0;
 113
 114         if (clk == NULL || IS_ERR(clk))
 115                 return 0;
 116
 117         spin_lock_irqsave(&clockfw_lock, flags);
 118         ret = clk->rate;
 119         spin_unlock_irqrestore(&clockfw_lock, flags);
 120
 121         return ret;
 122 }
 123 EXPORT_SYMBOL(clk_get_rate);
 124
 125 /*-------------------------------------------------------------------------
 126  * Optional clock functions defined in include/linux/clk.h
 127  *-------------------------------------------------------------------------*/
 128
 129 long clk_round_rate(struct clk *clk, unsigned long rate)
 130 {
 131         unsigned long flags;
 132         long ret = 0;
 133
 134         if (clk == NULL || IS_ERR(clk))
 135                 return ret;
 136
 137         spin_lock_irqsave(&clockfw_lock, flags);
 138         if (arch_clock->clk_round_rate)
 139                 ret = arch_clock->clk_round_rate(clk, rate);
 140         spin_unlock_irqrestore(&clockfw_lock, flags);
 141
 142         return ret;
 143 }
 144 EXPORT_SYMBOL(clk_round_rate);
 145
 146 int clk_set_rate(struct clk *clk, unsigned long rate)
 147 {
 148         unsigned long flags;
 149         int ret = -EINVAL;
 150
 151         if (clk == NULL || IS_ERR(clk))
 152                 return ret;
 153
 154         spin_lock_irqsave(&clockfw_lock, flags);
 155         if (arch_clock->clk_set_rate)
 156                 ret = arch_clock->clk_set_rate(clk, rate);
 157         if (ret == 0) {
 158                 if (clk->recalc)
 159                         clk->rate = clk->recalc(clk);
 160                 propagate_rate(clk);
 161         }
 162         spin_unlock_irqrestore(&clockfw_lock, flags);
 163
 164         return ret;
 165 }
 166 EXPORT_SYMBOL(clk_set_rate);
 167
 168 int clk_set_parent(struct clk *clk, struct clk *parent)
 169 {
 170         unsigned long flags;
 171         int ret = -EINVAL;
 172
 173         if (cpu_is_omap44xx())
 174         /* OMAP4 clk framework not supported yet */
 175                 return 0;
 176         if (clk == NULL || IS_ERR(clk) || parent == NULL || IS_ERR(parent))
 177                 return ret;
 178
 179         spin_lock_irqsave(&clockfw_lock, flags);
 180         if (clk->usecount == 0) {
 181                 if (arch_clock->clk_set_parent)
 182                         ret = arch_clock->clk_set_parent(clk, parent);
 183                 if (ret == 0) {
 184                         if (clk->recalc)
 185                                 clk->rate = clk->recalc(clk);
 186                         propagate_rate(clk);
 187                 }
 188         } else
 189                 ret = -EBUSY;
 190         spin_unlock_irqrestore(&clockfw_lock, flags);
 191
 192         return ret;
 193 }
 194 EXPORT_SYMBOL(clk_set_parent);
 195
 196 struct clk *clk_get_parent(struct clk *clk)
 197 {
 198         return clk->parent;
 199 }
 200 EXPORT_SYMBOL(clk_get_parent);
 201
 202 /*-------------------------------------------------------------------------
 203  * OMAP specific clock functions shared between omap1 and omap2
 204  *-------------------------------------------------------------------------*/
 205
 206 unsigned int __initdata mpurate;
 207
 208 /*
 209  * By default we use the rate set by the bootloader.
 210  * You can override this with mpurate= cmdline option.
 211  */
 212 static int __init omap_clk_setup(char *str)
 213 {
 214         get_option(&str, &mpurate);
 215
 216         if (!mpurate)
 217                 return 1;
 218
 219         if (mpurate < 1000)
 220                 mpurate *= 1000000;
 221
 222         return 1;
 223 }
 224 __setup("mpurate=", omap_clk_setup);
 225
 226 /* Used for clocks that always have same value as the parent clock */
 227 unsigned long followparent_recalc(struct clk *clk)
 228 {
 229         return clk->parent->rate;
 230 }
 231
 232 void clk_reparent(struct clk *child, struct clk *parent)
 233 {
 234         list_del_init(&child->sibling);
 235         if (parent)
 236                 list_add(&child->sibling, &parent->children);
 237         child->parent = parent;
 238
 239         /* now do the debugfs renaming to reattach the child
 240            to the proper parent */
 241 }
 242
 243 /* Propagate rate to children */
 244 void propagate_rate(struct clk * tclk)
 245 {
 246         struct clk *clkp;
 247
 248         list_for_each_entry(clkp, &tclk->children, sibling) {
 249                 if (clkp->recalc)
 250                         clkp->rate = clkp->recalc(clkp);
 251                 propagate_rate(clkp);
 252         }
 253 }
 254
 255 static LIST_HEAD(root_clks);
 256
 257 /**
 258  * recalculate_root_clocks - recalculate and propagate all root clocks
 259  *
 260  * Recalculates all root clocks (clocks with no parent), which if the
 261  * clock's .recalc is set correctly, should also propagate their rates.
 262  * Called at init.
 263  */
 264 void recalculate_root_clocks(void)
 265 {
 266         struct clk *clkp;
 267
 268         list_for_each_entry(clkp, &root_clks, sibling) {
 269                 if (clkp->recalc)
 270                         clkp->rate = clkp->recalc(clkp);
 271                 propagate_rate(clkp);
 272         }
 273 }
 274
 275 /**
 276  * clk_preinit - initialize any fields in the struct clk before clk init
 277  * @clk: struct clk * to initialize
 278  *
 279  * Initialize any struct clk fields needed before normal clk initialization
 280  * can run.  No return value.
 281  */
 282 void clk_preinit(struct clk *clk)
 283 {
 284         INIT_LIST_HEAD(&clk->children);
 285 }
 286
 287 int clk_register(struct clk *clk)
 288 {
 289         if (clk == NULL || IS_ERR(clk))
 290                 return -EINVAL;
 291
 292         /*
 293          * trap out already registered clocks
 294          */
 295         if (clk->node.next || clk->node.prev)
 296                 return 0;
 297
 298         mutex_lock(&clocks_mutex);
 299         if (clk->parent)
 300                 list_add(&clk->sibling, &clk->parent->children);
 301         else
 302                 list_add(&clk->sibling, &root_clks);
 303
 304         list_add(&clk->node, &clocks);
 305         if (clk->init)
 306                 clk->init(clk);
 307         mutex_unlock(&clocks_mutex);
 308
 309         return 0;
 310 }
 311 EXPORT_SYMBOL(clk_register);
 312
 313 void clk_unregister(struct clk *clk)
 314 {
 315         if (clk == NULL || IS_ERR(clk))
 316                 return;
 317
 318         mutex_lock(&clocks_mutex);
 319         list_del(&clk->sibling);
 320         list_del(&clk->node);
 321         mutex_unlock(&clocks_mutex);
 322 }
 323 EXPORT_SYMBOL(clk_unregister);
 324
 325 void clk_enable_init_clocks(void)
 326 {
 327         struct clk *clkp;
 328
 329         list_for_each_entry(clkp, &clocks, node) {
 330                 if (clkp->flags & ENABLE_ON_INIT)
 331                         clk_enable(clkp);
 332         }
 333 }
 334 EXPORT_SYMBOL(clk_enable_init_clocks);
 335
 336 /*
 337  * Low level helpers
 338  */
 339 static int clkll_enable_null(struct clk *clk)
 340 {
 341         return 0;
 342 }
 343
 344 static void clkll_disable_null(struct clk *clk)
 345 {
 346 }
 347
 348 const struct clkops clkops_null = {
 349         .enable         = clkll_enable_null,
 350         .disable        = clkll_disable_null,
 351 };
 352
 353 #ifdef CONFIG_CPU_FREQ
 354 void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
 355 {
 356         unsigned long flags;
 357
 358         spin_lock_irqsave(&clockfw_lock, flags);
 359         if (arch_clock->clk_init_cpufreq_table)
 360                 arch_clock->clk_init_cpufreq_table(table);
 361         spin_unlock_irqrestore(&clockfw_lock, flags);
 362 }
 363 EXPORT_SYMBOL(clk_init_cpufreq_table);
 364 #endif
 365
 366 /*-------------------------------------------------------------------------*/
 367
 368 #ifdef CONFIG_OMAP_RESET_CLOCKS
 369 /*
 370  * Disable any unused clocks left on by the bootloader
 371  */
 372 static int __init clk_disable_unused(void)
 373 {
 374         struct clk *ck;
 375         unsigned long flags;
 376
 377         list_for_each_entry(ck, &clocks, node) {
 378                 if (ck->ops == &clkops_null)
 379                         continue;
 380
 381                 if (ck->usecount > 0 || ck->enable_reg == 0)
 382                         continue;
 383
 384                 spin_lock_irqsave(&clockfw_lock, flags);
 385                 if (arch_clock->clk_disable_unused)
 386                         arch_clock->clk_disable_unused(ck);
 387                 spin_unlock_irqrestore(&clockfw_lock, flags);
 388         }
 389
 390         return 0;
 391 }
 392 late_initcall(clk_disable_unused);
 393 #endif
 394
 395 int __init clk_init(struct clk_functions * custom_clocks)
 396 {
 397         if (!custom_clocks) {
 398                 printk(KERN_ERR "No custom clock functions registered\n");
 399                 BUG();
 400         }
 401
 402         arch_clock = custom_clocks;
 403
 404         return 0;
 405 }
 406
 407 #if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
 408 /*
 409  *      debugfs support to trace clock tree hierarchy and attributes
 410  */
 411 static struct dentry *clk_debugfs_root;
 412
 413 static int clk_debugfs_register_one(struct clk *c)
 414 {
 415         int err;
 416         struct dentry *d, *child;
 417         struct clk *pa = c->parent;
 418         char s[255];
 419         char *p = s;
 420
 421         p += sprintf(p, "%s", c->name);
 422         if (c->id != 0)
 423                 sprintf(p, ":%d", c->id);
 424         d = debugfs_create_dir(s, pa ? pa->dent : clk_debugfs_root);
 425         if (!d)
 426                 return -ENOMEM;
 427         c->dent = d;
 428
 429         d = debugfs_create_u8("usecount", S_IRUGO, c->dent, (u8 *)&c->usecount);
 430         if (!d) {
 431                 err = -ENOMEM;
 432                 goto err_out;
 433         }
 434         d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
 435         if (!d) {
 436                 err = -ENOMEM;
 437                 goto err_out;
 438         }
 439         d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
 440         if (!d) {
 441                 err = -ENOMEM;
 442                 goto err_out;
 443         }
 444         return 0;
 445
 446 err_out:
 447         d = c->dent;
 448         list_for_each_entry(child, &d->d_subdirs, d_u.d_child)
 449                 debugfs_remove(child);
 450         debugfs_remove(c->dent);
 451         return err;
 452 }
 453
 454 static int clk_debugfs_register(struct clk *c)
 455 {
 456         int err;
 457         struct clk *pa = c->parent;
 458
 459         if (pa && !pa->dent) {
 460                 err = clk_debugfs_register(pa);
 461                 if (err)
 462                         return err;
 463         }
 464
 465         if (!c->dent) {
 466                 err = clk_debugfs_register_one(c);
 467                 if (err)
 468                         return err;
 469         }
 470         return 0;
 471 }
 472
 473 static int __init clk_debugfs_init(void)
 474 {
 475         struct clk *c;
 476         struct dentry *d;
 477         int err;
 478
 479         d = debugfs_create_dir("clock", NULL);
 480         if (!d)
 481                 return -ENOMEM;
 482         clk_debugfs_root = d;
 483
 484         list_for_each_entry(c, &clocks, node) {
 485                 err = clk_debugfs_register(c);
 486                 if (err)
 487                         goto err_out;
 488         }
 489         return 0;
 490 err_out:
 491         debugfs_remove_recursive(clk_debugfs_root);
 492         return err;
 493 }
 494 late_initcall(clk_debugfs_init);
 495
 496 #endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */