arch/sh/kernel/cpu/clock.c

   1 /*
   2  * arch/sh/kernel/cpu/clock.c - SuperH clock framework
   3  *
   4  *  Copyright (C) 2005 - 2009  Paul Mundt
   5  *
   6  * This clock framework is derived from the OMAP version by:
   7  *
   8  *      Copyright (C) 2004 - 2008 Nokia Corporation
   9  *      Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
  10  *
  11  *  Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
  12  *
  13  * This file is subject to the terms and conditions of the GNU General Public
  14  * License.  See the file "COPYING" in the main directory of this archive
  15  * for more details.
  16  */
  17 #include <linux/kernel.h>
  18 #include <linux/init.h>
  19 #include <linux/module.h>
  20 #include <linux/mutex.h>
  21 #include <linux/list.h>
  22 #include <linux/kobject.h>
  23 #include <linux/sysdev.h>
  24 #include <linux/seq_file.h>
  25 #include <linux/err.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/debugfs.h>
  28 #include <linux/cpufreq.h>
  29 #include <linux/clk.h>
  30 #include <asm/clock.h>
  31 #include <asm/machvec.h>
  32
  33 static LIST_HEAD(clock_list);
  34 static DEFINE_SPINLOCK(clock_lock);
  35 static DEFINE_MUTEX(clock_list_sem);
  36
  37 void clk_rate_table_build(struct clk *clk,
  38                           struct cpufreq_frequency_table *freq_table,
  39                           int nr_freqs,
  40                           struct clk_div_mult_table *src_table,
  41                           unsigned long *bitmap)
  42 {
  43         unsigned long mult, div;
  44         unsigned long freq;
  45         int i;
  46
  47         for (i = 0; i < nr_freqs; i++) {
  48                 div = 1;
  49                 mult = 1;
  50
  51                 if (src_table->divisors && i < src_table->nr_divisors)
  52                         div = src_table->divisors[i];
  53
  54                 if (src_table->multipliers && i < src_table->nr_multipliers)
  55                         mult = src_table->multipliers[i];
  56
  57                 if (!div || !mult || (bitmap && !test_bit(i, bitmap)))
  58                         freq = CPUFREQ_ENTRY_INVALID;
  59                 else
  60                         freq = clk->parent->rate * mult / div;
  61
  62                 freq_table[i].index = i;
  63                 freq_table[i].frequency = freq;
  64         }
  65
  66         /* Termination entry */
  67         freq_table[i].index = i;
  68         freq_table[i].frequency = CPUFREQ_TABLE_END;
  69 }
  70
  71 long clk_rate_table_round(struct clk *clk,
  72                           struct cpufreq_frequency_table *freq_table,
  73                           unsigned long rate)
  74 {
  75         unsigned long rate_error, rate_error_prev = ~0UL;
  76         unsigned long rate_best_fit = rate;
  77         unsigned long highest, lowest;
  78         int i;
  79
  80         highest = lowest = 0;
  81
  82         for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
  83                 unsigned long freq = freq_table[i].frequency;
  84
  85                 if (freq == CPUFREQ_ENTRY_INVALID)
  86                         continue;
  87
  88                 if (freq > highest)
  89                         highest = freq;
  90                 if (freq < lowest)
  91                         lowest = freq;
  92
  93                 rate_error = abs(freq - rate);
  94                 if (rate_error < rate_error_prev) {
  95                         rate_best_fit = freq;
  96                         rate_error_prev = rate_error;
  97                 }
  98
  99                 if (rate_error == 0)
 100                         break;
 101         }
 102
 103         if (rate >= highest)
 104                 rate_best_fit = highest;
 105         if (rate <= lowest)
 106                 rate_best_fit = lowest;
 107
 108         return rate_best_fit;
 109 }
 110
 111 int clk_rate_table_find(struct clk *clk,
 112                         struct cpufreq_frequency_table *freq_table,
 113                         unsigned long rate)
 114 {
 115         int i;
 116
 117         for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
 118                 unsigned long freq = freq_table[i].frequency;
 119
 120                 if (freq == CPUFREQ_ENTRY_INVALID)
 121                         continue;
 122
 123                 if (freq == rate)
 124                         return i;
 125         }
 126
 127         return -ENOENT;
 128 }
 129
 130 /* Used for clocks that always have same value as the parent clock */
 131 unsigned long followparent_recalc(struct clk *clk)
 132 {
 133         return clk->parent ? clk->parent->rate : 0;
 134 }
 135
 136 int clk_reparent(struct clk *child, struct clk *parent)
 137 {
 138         list_del_init(&child->sibling);
 139         if (parent)
 140                 list_add(&child->sibling, &parent->children);
 141         child->parent = parent;
 142
 143         /* now do the debugfs renaming to reattach the child
 144            to the proper parent */
 145
 146         return 0;
 147 }
 148
 149 /* Propagate rate to children */
 150 void propagate_rate(struct clk *tclk)
 151 {
 152         struct clk *clkp;
 153
 154         list_for_each_entry(clkp, &tclk->children, sibling) {
 155                 if (clkp->ops && clkp->ops->recalc)
 156                         clkp->rate = clkp->ops->recalc(clkp);
 157
 158                 propagate_rate(clkp);
 159         }
 160 }
 161
 162 static void __clk_disable(struct clk *clk)
 163 {
 164         if (clk->usecount == 0) {
 165                 printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
 166                        clk->name);
 167                 WARN_ON(1);
 168                 return;
 169         }
 170
 171         if (!(--clk->usecount)) {
 172                 if (likely(clk->ops && clk->ops->disable))
 173                         clk->ops->disable(clk);
 174                 if (likely(clk->parent))
 175                         __clk_disable(clk->parent);
 176         }
 177 }
 178
 179 void clk_disable(struct clk *clk)
 180 {
 181         unsigned long flags;
 182
 183         if (!clk)
 184                 return;
 185
 186         spin_lock_irqsave(&clock_lock, flags);
 187         __clk_disable(clk);
 188         spin_unlock_irqrestore(&clock_lock, flags);
 189 }
 190 EXPORT_SYMBOL_GPL(clk_disable);
 191
 192 static int __clk_enable(struct clk *clk)
 193 {
 194         int ret = 0;
 195
 196         if (clk->usecount++ == 0) {
 197                 if (clk->parent) {
 198                         ret = __clk_enable(clk->parent);
 199                         if (unlikely(ret))
 200                                 goto err;
 201                 }
 202
 203                 if (clk->ops && clk->ops->enable) {
 204                         ret = clk->ops->enable(clk);
 205                         if (ret) {
 206                                 if (clk->parent)
 207                                         __clk_disable(clk->parent);
 208                                 goto err;
 209                         }
 210                 }
 211         }
 212
 213         return ret;
 214 err:
 215         clk->usecount--;
 216         return ret;
 217 }
 218
 219 int clk_enable(struct clk *clk)
 220 {
 221         unsigned long flags;
 222         int ret;
 223
 224         if (!clk)
 225                 return -EINVAL;
 226
 227         spin_lock_irqsave(&clock_lock, flags);
 228         ret = __clk_enable(clk);
 229         spin_unlock_irqrestore(&clock_lock, flags);
 230
 231         return ret;
 232 }
 233 EXPORT_SYMBOL_GPL(clk_enable);
 234
 235 static LIST_HEAD(root_clks);
 236
 237 /**
 238  * recalculate_root_clocks - recalculate and propagate all root clocks
 239  *
 240  * Recalculates all root clocks (clocks with no parent), which if the
 241  * clock's .recalc is set correctly, should also propagate their rates.
 242  * Called at init.
 243  */
 244 void recalculate_root_clocks(void)
 245 {
 246         struct clk *clkp;
 247
 248         list_for_each_entry(clkp, &root_clks, sibling) {
 249                 if (clkp->ops && clkp->ops->recalc)
 250                         clkp->rate = clkp->ops->recalc(clkp);
 251                 propagate_rate(clkp);
 252         }
 253 }
 254
 255 int clk_register(struct clk *clk)
 256 {
 257         if (clk == NULL || IS_ERR(clk))
 258                 return -EINVAL;
 259
 260         /*
 261          * trap out already registered clocks
 262          */
 263         if (clk->node.next || clk->node.prev)
 264                 return 0;
 265
 266         mutex_lock(&clock_list_sem);
 267
 268         INIT_LIST_HEAD(&clk->children);
 269         clk->usecount = 0;
 270
 271         if (clk->parent)
 272                 list_add(&clk->sibling, &clk->parent->children);
 273         else
 274                 list_add(&clk->sibling, &root_clks);
 275
 276         list_add(&clk->node, &clock_list);
 277         if (clk->ops && clk->ops->init)
 278                 clk->ops->init(clk);
 279         mutex_unlock(&clock_list_sem);
 280
 281         return 0;
 282 }
 283 EXPORT_SYMBOL_GPL(clk_register);
 284
 285 void clk_unregister(struct clk *clk)
 286 {
 287         mutex_lock(&clock_list_sem);
 288         list_del(&clk->sibling);
 289         list_del(&clk->node);
 290         mutex_unlock(&clock_list_sem);
 291 }
 292 EXPORT_SYMBOL_GPL(clk_unregister);
 293
 294 static void clk_enable_init_clocks(void)
 295 {
 296         struct clk *clkp;
 297
 298         list_for_each_entry(clkp, &clock_list, node)
 299                 if (clkp->flags & CLK_ENABLE_ON_INIT)
 300                         clk_enable(clkp);
 301 }
 302
 303 unsigned long clk_get_rate(struct clk *clk)
 304 {
 305         return clk->rate;
 306 }
 307 EXPORT_SYMBOL_GPL(clk_get_rate);
 308
 309 int clk_set_rate(struct clk *clk, unsigned long rate)
 310 {
 311         return clk_set_rate_ex(clk, rate, 0);
 312 }
 313 EXPORT_SYMBOL_GPL(clk_set_rate);
 314
 315 int clk_set_rate_ex(struct clk *clk, unsigned long rate, int algo_id)
 316 {
 317         int ret = -EOPNOTSUPP;
 318         unsigned long flags;
 319
 320         spin_lock_irqsave(&clock_lock, flags);
 321
 322         if (likely(clk->ops && clk->ops->set_rate)) {
 323                 ret = clk->ops->set_rate(clk, rate, algo_id);
 324                 if (ret != 0)
 325                         goto out_unlock;
 326         } else {
 327                 clk->rate = rate;
 328                 ret = 0;
 329         }
 330
 331         if (clk->ops && clk->ops->recalc)
 332                 clk->rate = clk->ops->recalc(clk);
 333
 334         propagate_rate(clk);
 335
 336 out_unlock:
 337         spin_unlock_irqrestore(&clock_lock, flags);
 338
 339         return ret;
 340 }
 341 EXPORT_SYMBOL_GPL(clk_set_rate_ex);
 342
 343 int clk_set_parent(struct clk *clk, struct clk *parent)
 344 {
 345         unsigned long flags;
 346         int ret = -EINVAL;
 347
 348         if (!parent || !clk)
 349                 return ret;
 350         if (clk->parent == parent)
 351                 return 0;
 352
 353         spin_lock_irqsave(&clock_lock, flags);
 354         if (clk->usecount == 0) {
 355                 if (clk->ops->set_parent)
 356                         ret = clk->ops->set_parent(clk, parent);
 357                 else
 358                         ret = clk_reparent(clk, parent);
 359
 360                 if (ret == 0) {
 361                         pr_debug("clock: set parent of %s to %s (new rate %ld)\n",
 362                                  clk->name, clk->parent->name, clk->rate);
 363                         if (clk->ops->recalc)
 364                                 clk->rate = clk->ops->recalc(clk);
 365                         propagate_rate(clk);
 366                 }
 367         } else
 368                 ret = -EBUSY;
 369         spin_unlock_irqrestore(&clock_lock, flags);
 370
 371         return ret;
 372 }
 373 EXPORT_SYMBOL_GPL(clk_set_parent);
 374
 375 struct clk *clk_get_parent(struct clk *clk)
 376 {
 377         return clk->parent;
 378 }
 379 EXPORT_SYMBOL_GPL(clk_get_parent);
 380
 381 long clk_round_rate(struct clk *clk, unsigned long rate)
 382 {
 383         if (likely(clk->ops && clk->ops->round_rate)) {
 384                 unsigned long flags, rounded;
 385
 386                 spin_lock_irqsave(&clock_lock, flags);
 387                 rounded = clk->ops->round_rate(clk, rate);
 388                 spin_unlock_irqrestore(&clock_lock, flags);
 389
 390                 return rounded;
 391         }
 392
 393         return clk_get_rate(clk);
 394 }
 395 EXPORT_SYMBOL_GPL(clk_round_rate);
 396
 397 /*
 398  * Returns a clock. Note that we first try to use device id on the bus
 399  * and clock name. If this fails, we try to use clock name only.
 400  */
 401 struct clk *clk_get(struct device *dev, const char *id)
 402 {
 403         const char *dev_id = dev ? dev_name(dev) : NULL;
 404         struct clk *p, *clk = ERR_PTR(-ENOENT);
 405         int idno;
 406
 407         clk = clk_get_sys(dev_id, id);
 408         if (clk && !IS_ERR(clk))
 409                 return clk;
 410
 411         if (dev == NULL || dev->bus != &platform_bus_type)
 412                 idno = -1;
 413         else
 414                 idno = to_platform_device(dev)->id;
 415
 416         mutex_lock(&clock_list_sem);
 417         list_for_each_entry(p, &clock_list, node) {
 418                 if (p->id == idno &&
 419                     strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
 420                         clk = p;
 421                         goto found;
 422                 }
 423         }
 424
 425         list_for_each_entry(p, &clock_list, node) {
 426                 if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
 427                         clk = p;
 428                         break;
 429                 }
 430         }
 431
 432 found:
 433         mutex_unlock(&clock_list_sem);
 434
 435         return clk;
 436 }
 437 EXPORT_SYMBOL_GPL(clk_get);
 438
 439 void clk_put(struct clk *clk)
 440 {
 441         if (clk && !IS_ERR(clk))
 442                 module_put(clk->owner);
 443 }
 444 EXPORT_SYMBOL_GPL(clk_put);
 445
 446 #ifdef CONFIG_PM
 447 static int clks_sysdev_suspend(struct sys_device *dev, pm_message_t state)
 448 {
 449         static pm_message_t prev_state;
 450         struct clk *clkp;
 451
 452         switch (state.event) {
 453         case PM_EVENT_ON:
 454                 /* Resumeing from hibernation */
 455                 if (prev_state.event != PM_EVENT_FREEZE)
 456                         break;
 457
 458                 list_for_each_entry(clkp, &clock_list, node) {
 459                         if (likely(clkp->ops)) {
 460                                 unsigned long rate = clkp->rate;
 461
 462                                 if (likely(clkp->ops->set_parent))
 463                                         clkp->ops->set_parent(clkp,
 464                                                 clkp->parent);
 465                                 if (likely(clkp->ops->set_rate))
 466                                         clkp->ops->set_rate(clkp,
 467                                                 rate, NO_CHANGE);
 468                                 else if (likely(clkp->ops->recalc))
 469                                         clkp->rate = clkp->ops->recalc(clkp);
 470                         }
 471                 }
 472                 break;
 473         case PM_EVENT_FREEZE:
 474                 break;
 475         case PM_EVENT_SUSPEND:
 476                 break;
 477         }
 478
 479         prev_state = state;
 480         return 0;
 481 }
 482
 483 static int clks_sysdev_resume(struct sys_device *dev)
 484 {
 485         return clks_sysdev_suspend(dev, PMSG_ON);
 486 }
 487
 488 static struct sysdev_class clks_sysdev_class = {
 489         .name = "clks",
 490 };
 491
 492 static struct sysdev_driver clks_sysdev_driver = {
 493         .suspend = clks_sysdev_suspend,
 494         .resume = clks_sysdev_resume,
 495 };
 496
 497 static struct sys_device clks_sysdev_dev = {
 498         .cls = &clks_sysdev_class,
 499 };
 500
 501 static int __init clk_sysdev_init(void)
 502 {
 503         sysdev_class_register(&clks_sysdev_class);
 504         sysdev_driver_register(&clks_sysdev_class, &clks_sysdev_driver);
 505         sysdev_register(&clks_sysdev_dev);
 506
 507         return 0;
 508 }
 509 subsys_initcall(clk_sysdev_init);
 510 #endif
 511
 512 int __init clk_init(void)
 513 {
 514         int ret;
 515
 516         ret = arch_clk_init();
 517         if (unlikely(ret)) {
 518                 pr_err("%s: CPU clock registration failed.\n", __func__);
 519                 return ret;
 520         }
 521
 522         if (sh_mv.mv_clk_init) {
 523                 ret = sh_mv.mv_clk_init();
 524                 if (unlikely(ret)) {
 525                         pr_err("%s: machvec clock initialization failed.\n",
 526                                __func__);
 527                         return ret;
 528                 }
 529         }
 530
 531         /* Kick the child clocks.. */
 532         recalculate_root_clocks();
 533
 534         /* Enable the necessary init clocks */
 535         clk_enable_init_clocks();
 536
 537         return ret;
 538 }
 539
 540 /*
 541  *      debugfs support to trace clock tree hierarchy and attributes
 542  */
 543 static struct dentry *clk_debugfs_root;
 544
 545 static int clk_debugfs_register_one(struct clk *c)
 546 {
 547         int err;
 548         struct dentry *d, *child, *child_tmp;
 549         struct clk *pa = c->parent;
 550         char s[255];
 551         char *p = s;
 552
 553         p += sprintf(p, "%s", c->name);
 554         if (c->id >= 0)
 555                 sprintf(p, ":%d", c->id);
 556         d = debugfs_create_dir(s, pa ? pa->dentry : clk_debugfs_root);
 557         if (!d)
 558                 return -ENOMEM;
 559         c->dentry = d;
 560
 561         d = debugfs_create_u8("usecount", S_IRUGO, c->dentry, (u8 *)&c->usecount);
 562         if (!d) {
 563                 err = -ENOMEM;
 564                 goto err_out;
 565         }
 566         d = debugfs_create_u32("rate", S_IRUGO, c->dentry, (u32 *)&c->rate);
 567         if (!d) {
 568                 err = -ENOMEM;
 569                 goto err_out;
 570         }
 571         d = debugfs_create_x32("flags", S_IRUGO, c->dentry, (u32 *)&c->flags);
 572         if (!d) {
 573                 err = -ENOMEM;
 574                 goto err_out;
 575         }
 576         return 0;
 577
 578 err_out:
 579         d = c->dentry;
 580         list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
 581                 debugfs_remove(child);
 582         debugfs_remove(c->dentry);
 583         return err;
 584 }
 585
 586 static int clk_debugfs_register(struct clk *c)
 587 {
 588         int err;
 589         struct clk *pa = c->parent;
 590
 591         if (pa && !pa->dentry) {
 592                 err = clk_debugfs_register(pa);
 593                 if (err)
 594                         return err;
 595         }
 596
 597         if (!c->dentry) {
 598                 err = clk_debugfs_register_one(c);
 599                 if (err)
 600                         return err;
 601         }
 602         return 0;
 603 }
 604
 605 static int __init clk_debugfs_init(void)
 606 {
 607         struct clk *c;
 608         struct dentry *d;
 609         int err;
 610
 611         d = debugfs_create_dir("clock", NULL);
 612         if (!d)
 613                 return -ENOMEM;
 614         clk_debugfs_root = d;
 615
 616         list_for_each_entry(c, &clock_list, node) {
 617                 err = clk_debugfs_register(c);
 618                 if (err)
 619                         goto err_out;
 620         }
 621         return 0;
 622 err_out:
 623         debugfs_remove(clk_debugfs_root); /* REVISIT: Cleanup correctly */
 624         return err;
 625 }
 626 late_initcall(clk_debugfs_init);