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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/list.h>
  16 #include <linux/errno.h>
  17 #include <linux/err.h>
  18 #include <linux/string.h>
  19 #include <linux/clk.h>
  20 #include <linux/mutex.h>
  21 #include <linux/cpufreq.h>
  22 #include <linux/debugfs.h>
  23 #include <linux/io.h>
  24
  25 #include <plat/clock.h>
  26
  27 static LIST_HEAD(clocks);
  28 static DEFINE_MUTEX(clocks_mutex);
  29 static DEFINE_SPINLOCK(clockfw_lock);
  30
  31 static struct clk_functions *arch_clock;
  32
  33 /*
  34  * Standard clock functions defined in include/linux/clk.h
  35  */
  36
  37 int clk_enable(struct clk *clk)
  38 {
  39         unsigned long flags;
  40         int ret = 0;
  41
  42         if (clk == NULL || IS_ERR(clk))
  43                 return -EINVAL;
  44
  45         spin_lock_irqsave(&clockfw_lock, flags);
  46         if (arch_clock->clk_enable)
  47                 ret = arch_clock->clk_enable(clk);
  48         spin_unlock_irqrestore(&clockfw_lock, flags);
  49
  50         return ret;
  51 }
  52 EXPORT_SYMBOL(clk_enable);
  53
  54 void clk_disable(struct clk *clk)
  55 {
  56         unsigned long flags;
  57
  58         if (clk == NULL || IS_ERR(clk))
  59                 return;
  60
  61         spin_lock_irqsave(&clockfw_lock, flags);
  62         if (clk->usecount == 0) {
  63                 printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
  64                        clk->name);
  65                 WARN_ON(1);
  66                 goto out;
  67         }
  68
  69         if (arch_clock->clk_disable)
  70                 arch_clock->clk_disable(clk);
  71
  72 out:
  73         spin_unlock_irqrestore(&clockfw_lock, flags);
  74 }
  75 EXPORT_SYMBOL(clk_disable);
  76
  77 unsigned long clk_get_rate(struct clk *clk)
  78 {
  79         unsigned long flags;
  80         unsigned long ret = 0;
  81
  82         if (clk == NULL || IS_ERR(clk))
  83                 return 0;
  84
  85         spin_lock_irqsave(&clockfw_lock, flags);
  86         ret = clk->rate;
  87         spin_unlock_irqrestore(&clockfw_lock, flags);
  88
  89         return ret;
  90 }
  91 EXPORT_SYMBOL(clk_get_rate);
  92
  93 /*
  94  * Optional clock functions defined in include/linux/clk.h
  95  */
  96
  97 long clk_round_rate(struct clk *clk, unsigned long rate)
  98 {
  99         unsigned long flags;
 100         long ret = 0;
 101
 102         if (clk == NULL || IS_ERR(clk))
 103                 return ret;
 104
 105         spin_lock_irqsave(&clockfw_lock, flags);
 106         if (arch_clock->clk_round_rate)
 107                 ret = arch_clock->clk_round_rate(clk, rate);
 108         spin_unlock_irqrestore(&clockfw_lock, flags);
 109
 110         return ret;
 111 }
 112 EXPORT_SYMBOL(clk_round_rate);
 113
 114 int clk_set_rate(struct clk *clk, unsigned long rate)
 115 {
 116         unsigned long flags;
 117         int ret = -EINVAL;
 118
 119         if (clk == NULL || IS_ERR(clk))
 120                 return ret;
 121
 122         spin_lock_irqsave(&clockfw_lock, flags);
 123         if (arch_clock->clk_set_rate)
 124                 ret = arch_clock->clk_set_rate(clk, rate);
 125         if (ret == 0) {
 126                 if (clk->recalc)
 127                         clk->rate = clk->recalc(clk);
 128                 propagate_rate(clk);
 129         }
 130         spin_unlock_irqrestore(&clockfw_lock, flags);
 131
 132         return ret;
 133 }
 134 EXPORT_SYMBOL(clk_set_rate);
 135
 136 int clk_set_parent(struct clk *clk, struct clk *parent)
 137 {
 138         unsigned long flags;
 139         int ret = -EINVAL;
 140
 141         if (cpu_is_omap44xx()) {
 142                 WARN(1, "clock: %s: not supported yet on OMAP4\n", __func__);
 143                 return 0;
 144         }
 145
 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  * omap_clk_get_by_name - locate OMAP struct clk by its name
 318  * @name: name of the struct clk to locate
 319  *
 320  * Locate an OMAP struct clk by its name.  Assumes that struct clk
 321  * names are unique.  Returns NULL if not found or a pointer to the
 322  * struct clk if found.
 323  */
 324 struct clk *omap_clk_get_by_name(const char *name)
 325 {
 326         struct clk *c;
 327         struct clk *ret = NULL;
 328
 329         mutex_lock(&clocks_mutex);
 330
 331         list_for_each_entry(c, &clocks, node) {
 332                 if (!strcmp(c->name, name)) {
 333                         ret = c;
 334                         break;
 335                 }
 336         }
 337
 338         mutex_unlock(&clocks_mutex);
 339
 340         return ret;
 341 }
 342
 343 /*
 344  * Low level helpers
 345  */
 346 static int clkll_enable_null(struct clk *clk)
 347 {
 348         return 0;
 349 }
 350
 351 static void clkll_disable_null(struct clk *clk)
 352 {
 353 }
 354
 355 const struct clkops clkops_null = {
 356         .enable         = clkll_enable_null,
 357         .disable        = clkll_disable_null,
 358 };
 359
 360 /*
 361  * Dummy clock
 362  *
 363  * Used for clock aliases that are needed on some OMAPs, but not others
 364  */
 365 struct clk dummy_ck = {
 366         .name   = "dummy",
 367         .ops    = &clkops_null,
 368 };
 369
 370 #ifdef CONFIG_CPU_FREQ
 371 void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
 372 {
 373         unsigned long flags;
 374
 375         spin_lock_irqsave(&clockfw_lock, flags);
 376         if (arch_clock->clk_init_cpufreq_table)
 377                 arch_clock->clk_init_cpufreq_table(table);
 378         spin_unlock_irqrestore(&clockfw_lock, flags);
 379 }
 380
 381 void clk_exit_cpufreq_table(struct cpufreq_frequency_table **table)
 382 {
 383         unsigned long flags;
 384
 385         spin_lock_irqsave(&clockfw_lock, flags);
 386         if (arch_clock->clk_exit_cpufreq_table)
 387                 arch_clock->clk_exit_cpufreq_table(table);
 388         spin_unlock_irqrestore(&clockfw_lock, flags);
 389 }
 390 #endif
 391
 392 /*
 393  *
 394  */
 395
 396 #ifdef CONFIG_OMAP_RESET_CLOCKS
 397 /*
 398  * Disable any unused clocks left on by the bootloader
 399  */
 400 static int __init clk_disable_unused(void)
 401 {
 402         struct clk *ck;
 403         unsigned long flags;
 404
 405         list_for_each_entry(ck, &clocks, node) {
 406                 if (ck->ops == &clkops_null)
 407                         continue;
 408
 409                 if (ck->usecount > 0 || !ck->enable_reg)
 410                         continue;
 411
 412                 spin_lock_irqsave(&clockfw_lock, flags);
 413                 if (arch_clock->clk_disable_unused)
 414                         arch_clock->clk_disable_unused(ck);
 415                 spin_unlock_irqrestore(&clockfw_lock, flags);
 416         }
 417
 418         return 0;
 419 }
 420 late_initcall(clk_disable_unused);
 421 #endif
 422
 423 int __init clk_init(struct clk_functions * custom_clocks)
 424 {
 425         if (!custom_clocks) {
 426                 printk(KERN_ERR "No custom clock functions registered\n");
 427                 BUG();
 428         }
 429
 430         arch_clock = custom_clocks;
 431
 432         return 0;
 433 }
 434
 435 #if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
 436 /*
 437  *      debugfs support to trace clock tree hierarchy and attributes
 438  */
 439 static struct dentry *clk_debugfs_root;
 440
 441 static int clk_debugfs_register_one(struct clk *c)
 442 {
 443         int err;
 444         struct dentry *d, *child, *child_tmp;
 445         struct clk *pa = c->parent;
 446         char s[255];
 447         char *p = s;
 448
 449         p += sprintf(p, "%s", c->name);
 450         d = debugfs_create_dir(s, pa ? pa->dent : clk_debugfs_root);
 451         if (!d)
 452                 return -ENOMEM;
 453         c->dent = d;
 454
 455         d = debugfs_create_u8("usecount", S_IRUGO, c->dent, (u8 *)&c->usecount);
 456         if (!d) {
 457                 err = -ENOMEM;
 458                 goto err_out;
 459         }
 460         d = debugfs_create_u32("rate", S_IRUGO, c->dent, (u32 *)&c->rate);
 461         if (!d) {
 462                 err = -ENOMEM;
 463                 goto err_out;
 464         }
 465         d = debugfs_create_x32("flags", S_IRUGO, c->dent, (u32 *)&c->flags);
 466         if (!d) {
 467                 err = -ENOMEM;
 468                 goto err_out;
 469         }
 470         return 0;
 471
 472 err_out:
 473         d = c->dent;
 474         list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
 475                 debugfs_remove(child);
 476         debugfs_remove(c->dent);
 477         return err;
 478 }
 479
 480 static int clk_debugfs_register(struct clk *c)
 481 {
 482         int err;
 483         struct clk *pa = c->parent;
 484
 485         if (pa && !pa->dent) {
 486                 err = clk_debugfs_register(pa);
 487                 if (err)
 488                         return err;
 489         }
 490
 491         if (!c->dent) {
 492                 err = clk_debugfs_register_one(c);
 493                 if (err)
 494                         return err;
 495         }
 496         return 0;
 497 }
 498
 499 static int __init clk_debugfs_init(void)
 500 {
 501         struct clk *c;
 502         struct dentry *d;
 503         int err;
 504
 505         d = debugfs_create_dir("clock", NULL);
 506         if (!d)
 507                 return -ENOMEM;
 508         clk_debugfs_root = d;
 509
 510         list_for_each_entry(c, &clocks, node) {
 511                 err = clk_debugfs_register(c);
 512                 if (err)
 513                         goto err_out;
 514         }
 515         return 0;
 516 err_out:
 517         debugfs_remove_recursive(clk_debugfs_root);
 518         return err;
 519 }
 520 late_initcall(clk_debugfs_init);
 521
 522 #endif /* defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS) */