drivers/sh/clk.c

   1 /*
   2  * drivers/sh/clk.c - SuperH clock framework
   3  *
   4  *  Copyright (C) 2005 - 2010  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 #define pr_fmt(fmt) "clock: " fmt
  18
  19 #include <linux/kernel.h>
  20 #include <linux/init.h>
  21 #include <linux/module.h>
  22 #include <linux/mutex.h>
  23 #include <linux/list.h>
  24 #include <linux/kobject.h>
  25 #include <linux/sysdev.h>
  26 #include <linux/seq_file.h>
  27 #include <linux/err.h>
  28 #include <linux/io.h>
  29 #include <linux/debugfs.h>
  30 #include <linux/cpufreq.h>
  31 #include <linux/clk.h>
  32 #include <linux/sh_clk.h>
  33
  34 static LIST_HEAD(clock_list);
  35 static DEFINE_SPINLOCK(clock_lock);
  36 static DEFINE_MUTEX(clock_list_sem);
  37
  38 void clk_rate_table_build(struct clk *clk,
  39                           struct cpufreq_frequency_table *freq_table,
  40                           int nr_freqs,
  41                           struct clk_div_mult_table *src_table,
  42                           unsigned long *bitmap)
  43 {
  44         unsigned long mult, div;
  45         unsigned long freq;
  46         int i;
  47
  48         clk->nr_freqs = nr_freqs;
  49
  50         for (i = 0; i < nr_freqs; i++) {
  51                 div = 1;
  52                 mult = 1;
  53
  54                 if (src_table->divisors && i < src_table->nr_divisors)
  55                         div = src_table->divisors[i];
  56
  57                 if (src_table->multipliers && i < src_table->nr_multipliers)
  58                         mult = src_table->multipliers[i];
  59
  60                 if (!div || !mult || (bitmap && !test_bit(i, bitmap)))
  61                         freq = CPUFREQ_ENTRY_INVALID;
  62                 else
  63                         freq = clk->parent->rate * mult / div;
  64
  65                 freq_table[i].index = i;
  66                 freq_table[i].frequency = freq;
  67         }
  68
  69         /* Termination entry */
  70         freq_table[i].index = i;
  71         freq_table[i].frequency = CPUFREQ_TABLE_END;
  72 }
  73
  74 struct clk_rate_round_data;
  75
  76 struct clk_rate_round_data {
  77         unsigned long rate;
  78         unsigned int min, max;
  79         long (*func)(unsigned int, struct clk_rate_round_data *);
  80         void *arg;
  81 };
  82
  83 #define for_each_frequency(pos, r, freq)                        \
  84         for (pos = r->min, freq = r->func(pos, r);              \
  85              pos < r->max; pos++, freq = r->func(pos, r))       \
  86                 if (unlikely(freq == 0))                        \
  87                         ;                                       \
  88                 else
  89
  90 static long clk_rate_round_helper(struct clk_rate_round_data *rounder)
  91 {
  92         unsigned long rate_error, rate_error_prev = ~0UL;
  93         unsigned long rate_best_fit = rounder->rate;
  94         unsigned long highest, lowest, freq;
  95         int i;
  96
  97         highest = 0;
  98         lowest = ~0UL;
  99
 100         for_each_frequency(i, rounder, freq) {
 101                 if (freq > highest)
 102                         highest = freq;
 103                 if (freq < lowest)
 104                         lowest = freq;
 105
 106                 rate_error = abs(freq - rounder->rate);
 107                 if (rate_error < rate_error_prev) {
 108                         rate_best_fit = freq;
 109                         rate_error_prev = rate_error;
 110                 }
 111
 112                 if (rate_error == 0)
 113                         break;
 114         }
 115
 116         if (rounder->rate >= highest)
 117                 rate_best_fit = highest;
 118         if (rounder->rate <= lowest)
 119                 rate_best_fit = lowest;
 120
 121         return rate_best_fit;
 122 }
 123
 124 static long clk_rate_table_iter(unsigned int pos,
 125                                 struct clk_rate_round_data *rounder)
 126 {
 127         struct cpufreq_frequency_table *freq_table = rounder->arg;
 128         unsigned long freq = freq_table[pos].frequency;
 129
 130         if (freq == CPUFREQ_ENTRY_INVALID)
 131                 freq = 0;
 132
 133         return freq;
 134 }
 135
 136 long clk_rate_table_round(struct clk *clk,
 137                           struct cpufreq_frequency_table *freq_table,
 138                           unsigned long rate)
 139 {
 140         struct clk_rate_round_data table_round = {
 141                 .min    = 0,
 142                 .max    = clk->nr_freqs,
 143                 .func   = clk_rate_table_iter,
 144                 .arg    = freq_table,
 145                 .rate   = rate,
 146         };
 147
 148         return clk_rate_round_helper(&table_round);
 149 }
 150
 151 static long clk_rate_div_range_iter(unsigned int pos,
 152                                     struct clk_rate_round_data *rounder)
 153 {
 154         return clk_get_rate(rounder->arg) / pos;
 155 }
 156
 157 long clk_rate_div_range_round(struct clk *clk, unsigned int div_min,
 158                               unsigned int div_max, unsigned long rate)
 159 {
 160         struct clk_rate_round_data div_range_round = {
 161                 .min    = div_min,
 162                 .max    = div_max,
 163                 .func   = clk_rate_div_range_iter,
 164                 .arg    = clk_get_parent(clk),
 165                 .rate   = rate,
 166         };
 167
 168         return clk_rate_round_helper(&div_range_round);
 169 }
 170
 171 int clk_rate_table_find(struct clk *clk,
 172                         struct cpufreq_frequency_table *freq_table,
 173                         unsigned long rate)
 174 {
 175         int i;
 176
 177         for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
 178                 unsigned long freq = freq_table[i].frequency;
 179
 180                 if (freq == CPUFREQ_ENTRY_INVALID)
 181                         continue;
 182
 183                 if (freq == rate)
 184                         return i;
 185         }
 186
 187         return -ENOENT;
 188 }
 189
 190 /* Used for clocks that always have same value as the parent clock */
 191 unsigned long followparent_recalc(struct clk *clk)
 192 {
 193         return clk->parent ? clk->parent->rate : 0;
 194 }
 195
 196 int clk_reparent(struct clk *child, struct clk *parent)
 197 {
 198         list_del_init(&child->sibling);
 199         if (parent)
 200                 list_add(&child->sibling, &parent->children);
 201         child->parent = parent;
 202
 203         /* now do the debugfs renaming to reattach the child
 204            to the proper parent */
 205
 206         return 0;
 207 }
 208
 209 /* Propagate rate to children */
 210 void propagate_rate(struct clk *tclk)
 211 {
 212         struct clk *clkp;
 213
 214         list_for_each_entry(clkp, &tclk->children, sibling) {
 215                 if (clkp->ops && clkp->ops->recalc)
 216                         clkp->rate = clkp->ops->recalc(clkp);
 217
 218                 propagate_rate(clkp);
 219         }
 220 }
 221
 222 static void __clk_disable(struct clk *clk)
 223 {
 224         if (WARN(!clk->usecount, "Trying to disable clock %p with 0 usecount\n",
 225                  clk))
 226                 return;
 227
 228         if (!(--clk->usecount)) {
 229                 if (likely(clk->ops && clk->ops->disable))
 230                         clk->ops->disable(clk);
 231                 if (likely(clk->parent))
 232                         __clk_disable(clk->parent);
 233         }
 234 }
 235
 236 void clk_disable(struct clk *clk)
 237 {
 238         unsigned long flags;
 239
 240         if (!clk)
 241                 return;
 242
 243         spin_lock_irqsave(&clock_lock, flags);
 244         __clk_disable(clk);
 245         spin_unlock_irqrestore(&clock_lock, flags);
 246 }
 247 EXPORT_SYMBOL_GPL(clk_disable);
 248
 249 static int __clk_enable(struct clk *clk)
 250 {
 251         int ret = 0;
 252
 253         if (clk->usecount++ == 0) {
 254                 if (clk->parent) {
 255                         ret = __clk_enable(clk->parent);
 256                         if (unlikely(ret))
 257                                 goto err;
 258                 }
 259
 260                 if (clk->ops && clk->ops->enable) {
 261                         ret = clk->ops->enable(clk);
 262                         if (ret) {
 263                                 if (clk->parent)
 264                                         __clk_disable(clk->parent);
 265                                 goto err;
 266                         }
 267                 }
 268         }
 269
 270         return ret;
 271 err:
 272         clk->usecount--;
 273         return ret;
 274 }
 275
 276 int clk_enable(struct clk *clk)
 277 {
 278         unsigned long flags;
 279         int ret;
 280
 281         if (!clk)
 282                 return -EINVAL;
 283
 284         spin_lock_irqsave(&clock_lock, flags);
 285         ret = __clk_enable(clk);
 286         spin_unlock_irqrestore(&clock_lock, flags);
 287
 288         return ret;
 289 }
 290 EXPORT_SYMBOL_GPL(clk_enable);
 291
 292 static LIST_HEAD(root_clks);
 293
 294 /**
 295  * recalculate_root_clocks - recalculate and propagate all root clocks
 296  *
 297  * Recalculates all root clocks (clocks with no parent), which if the
 298  * clock's .recalc is set correctly, should also propagate their rates.
 299  * Called at init.
 300  */
 301 void recalculate_root_clocks(void)
 302 {
 303         struct clk *clkp;
 304
 305         list_for_each_entry(clkp, &root_clks, sibling) {
 306                 if (clkp->ops && clkp->ops->recalc)
 307                         clkp->rate = clkp->ops->recalc(clkp);
 308                 propagate_rate(clkp);
 309         }
 310 }
 311
 312 static struct clk_mapping dummy_mapping;
 313
 314 static struct clk *lookup_root_clock(struct clk *clk)
 315 {
 316         while (clk->parent)
 317                 clk = clk->parent;
 318
 319         return clk;
 320 }
 321
 322 static int clk_establish_mapping(struct clk *clk)
 323 {
 324         struct clk_mapping *mapping = clk->mapping;
 325
 326         /*
 327          * Propagate mappings.
 328          */
 329         if (!mapping) {
 330                 struct clk *clkp;
 331
 332                 /*
 333                  * dummy mapping for root clocks with no specified ranges
 334                  */
 335                 if (!clk->parent) {
 336                         clk->mapping = &dummy_mapping;
 337                         return 0;
 338                 }
 339
 340                 /*
 341                  * If we're on a child clock and it provides no mapping of its
 342                  * own, inherit the mapping from its root clock.
 343                  */
 344                 clkp = lookup_root_clock(clk);
 345                 mapping = clkp->mapping;
 346                 BUG_ON(!mapping);
 347         }
 348
 349         /*
 350          * Establish initial mapping.
 351          */
 352         if (!mapping->base && mapping->phys) {
 353                 kref_init(&mapping->ref);
 354
 355                 mapping->base = ioremap_nocache(mapping->phys, mapping->len);
 356                 if (unlikely(!mapping->base))
 357                         return -ENXIO;
 358         } else if (mapping->base) {
 359                 /*
 360                  * Bump the refcount for an existing mapping
 361                  */
 362                 kref_get(&mapping->ref);
 363         }
 364
 365         clk->mapping = mapping;
 366         return 0;
 367 }
 368
 369 static void clk_destroy_mapping(struct kref *kref)
 370 {
 371         struct clk_mapping *mapping;
 372
 373         mapping = container_of(kref, struct clk_mapping, ref);
 374
 375         iounmap(mapping->base);
 376 }
 377
 378 static void clk_teardown_mapping(struct clk *clk)
 379 {
 380         struct clk_mapping *mapping = clk->mapping;
 381
 382         /* Nothing to do */
 383         if (mapping == &dummy_mapping)
 384                 return;
 385
 386         kref_put(&mapping->ref, clk_destroy_mapping);
 387         clk->mapping = NULL;
 388 }
 389
 390 int clk_register(struct clk *clk)
 391 {
 392         int ret;
 393
 394         if (clk == NULL || IS_ERR(clk))
 395                 return -EINVAL;
 396
 397         /*
 398          * trap out already registered clocks
 399          */
 400         if (clk->node.next || clk->node.prev)
 401                 return 0;
 402
 403         mutex_lock(&clock_list_sem);
 404
 405         INIT_LIST_HEAD(&clk->children);
 406         clk->usecount = 0;
 407
 408         ret = clk_establish_mapping(clk);
 409         if (unlikely(ret))
 410                 goto out_unlock;
 411
 412         if (clk->parent)
 413                 list_add(&clk->sibling, &clk->parent->children);
 414         else
 415                 list_add(&clk->sibling, &root_clks);
 416
 417         list_add(&clk->node, &clock_list);
 418         if (clk->ops && clk->ops->init)
 419                 clk->ops->init(clk);
 420
 421 out_unlock:
 422         mutex_unlock(&clock_list_sem);
 423
 424         return ret;
 425 }
 426 EXPORT_SYMBOL_GPL(clk_register);
 427
 428 void clk_unregister(struct clk *clk)
 429 {
 430         mutex_lock(&clock_list_sem);
 431         list_del(&clk->sibling);
 432         list_del(&clk->node);
 433         clk_teardown_mapping(clk);
 434         mutex_unlock(&clock_list_sem);
 435 }
 436 EXPORT_SYMBOL_GPL(clk_unregister);
 437
 438 void clk_enable_init_clocks(void)
 439 {
 440         struct clk *clkp;
 441
 442         list_for_each_entry(clkp, &clock_list, node)
 443                 if (clkp->flags & CLK_ENABLE_ON_INIT)
 444                         clk_enable(clkp);
 445 }
 446
 447 unsigned long clk_get_rate(struct clk *clk)
 448 {
 449         return clk->rate;
 450 }
 451 EXPORT_SYMBOL_GPL(clk_get_rate);
 452
 453 int clk_set_rate(struct clk *clk, unsigned long rate)
 454 {
 455         return clk_set_rate_ex(clk, rate, 0);
 456 }
 457 EXPORT_SYMBOL_GPL(clk_set_rate);
 458
 459 int clk_set_rate_ex(struct clk *clk, unsigned long rate, int algo_id)
 460 {
 461         int ret = -EOPNOTSUPP;
 462         unsigned long flags;
 463
 464         spin_lock_irqsave(&clock_lock, flags);
 465
 466         if (likely(clk->ops && clk->ops->set_rate)) {
 467                 ret = clk->ops->set_rate(clk, rate, algo_id);
 468                 if (ret != 0)
 469                         goto out_unlock;
 470         } else {
 471                 clk->rate = rate;
 472                 ret = 0;
 473         }
 474
 475         if (clk->ops && clk->ops->recalc)
 476                 clk->rate = clk->ops->recalc(clk);
 477
 478         propagate_rate(clk);
 479
 480 out_unlock:
 481         spin_unlock_irqrestore(&clock_lock, flags);
 482
 483         return ret;
 484 }
 485 EXPORT_SYMBOL_GPL(clk_set_rate_ex);
 486
 487 int clk_set_parent(struct clk *clk, struct clk *parent)
 488 {
 489         unsigned long flags;
 490         int ret = -EINVAL;
 491
 492         if (!parent || !clk)
 493                 return ret;
 494         if (clk->parent == parent)
 495                 return 0;
 496
 497         spin_lock_irqsave(&clock_lock, flags);
 498         if (clk->usecount == 0) {
 499                 if (clk->ops->set_parent)
 500                         ret = clk->ops->set_parent(clk, parent);
 501                 else
 502                         ret = clk_reparent(clk, parent);
 503
 504                 if (ret == 0) {
 505                         if (clk->ops->recalc)
 506                                 clk->rate = clk->ops->recalc(clk);
 507                         pr_debug("set parent of %p to %p (new rate %ld)\n",
 508                                  clk, clk->parent, clk->rate);
 509                         propagate_rate(clk);
 510                 }
 511         } else
 512                 ret = -EBUSY;
 513         spin_unlock_irqrestore(&clock_lock, flags);
 514
 515         return ret;
 516 }
 517 EXPORT_SYMBOL_GPL(clk_set_parent);
 518
 519 struct clk *clk_get_parent(struct clk *clk)
 520 {
 521         return clk->parent;
 522 }
 523 EXPORT_SYMBOL_GPL(clk_get_parent);
 524
 525 long clk_round_rate(struct clk *clk, unsigned long rate)
 526 {
 527         if (likely(clk->ops && clk->ops->round_rate)) {
 528                 unsigned long flags, rounded;
 529
 530                 spin_lock_irqsave(&clock_lock, flags);
 531                 rounded = clk->ops->round_rate(clk, rate);
 532                 spin_unlock_irqrestore(&clock_lock, flags);
 533
 534                 return rounded;
 535         }
 536
 537         return clk_get_rate(clk);
 538 }
 539 EXPORT_SYMBOL_GPL(clk_round_rate);
 540
 541 #ifdef CONFIG_PM
 542 static int clks_sysdev_suspend(struct sys_device *dev, pm_message_t state)
 543 {
 544         static pm_message_t prev_state;
 545         struct clk *clkp;
 546
 547         switch (state.event) {
 548         case PM_EVENT_ON:
 549                 /* Resumeing from hibernation */
 550                 if (prev_state.event != PM_EVENT_FREEZE)
 551                         break;
 552
 553                 list_for_each_entry(clkp, &clock_list, node) {
 554                         if (likely(clkp->ops)) {
 555                                 unsigned long rate = clkp->rate;
 556
 557                                 if (likely(clkp->ops->set_parent))
 558                                         clkp->ops->set_parent(clkp,
 559                                                 clkp->parent);
 560                                 if (likely(clkp->ops->set_rate))
 561                                         clkp->ops->set_rate(clkp,
 562                                                 rate, NO_CHANGE);
 563                                 else if (likely(clkp->ops->recalc))
 564                                         clkp->rate = clkp->ops->recalc(clkp);
 565                         }
 566                 }
 567                 break;
 568         case PM_EVENT_FREEZE:
 569                 break;
 570         case PM_EVENT_SUSPEND:
 571                 break;
 572         }
 573
 574         prev_state = state;
 575         return 0;
 576 }
 577
 578 static int clks_sysdev_resume(struct sys_device *dev)
 579 {
 580         return clks_sysdev_suspend(dev, PMSG_ON);
 581 }
 582
 583 static struct sysdev_class clks_sysdev_class = {
 584         .name = "clks",
 585 };
 586
 587 static struct sysdev_driver clks_sysdev_driver = {
 588         .suspend = clks_sysdev_suspend,
 589         .resume = clks_sysdev_resume,
 590 };
 591
 592 static struct sys_device clks_sysdev_dev = {
 593         .cls = &clks_sysdev_class,
 594 };
 595
 596 static int __init clk_sysdev_init(void)
 597 {
 598         sysdev_class_register(&clks_sysdev_class);
 599         sysdev_driver_register(&clks_sysdev_class, &clks_sysdev_driver);
 600         sysdev_register(&clks_sysdev_dev);
 601
 602         return 0;
 603 }
 604 subsys_initcall(clk_sysdev_init);
 605 #endif
 606
 607 /*
 608  *      debugfs support to trace clock tree hierarchy and attributes
 609  */
 610 static struct dentry *clk_debugfs_root;
 611
 612 static int clk_debugfs_register_one(struct clk *c)
 613 {
 614         int err;
 615         struct dentry *d, *child, *child_tmp;
 616         struct clk *pa = c->parent;
 617         char s[255];
 618         char *p = s;
 619
 620         p += sprintf(p, "%p", c);
 621         d = debugfs_create_dir(s, pa ? pa->dentry : clk_debugfs_root);
 622         if (!d)
 623                 return -ENOMEM;
 624         c->dentry = d;
 625
 626         d = debugfs_create_u8("usecount", S_IRUGO, c->dentry, (u8 *)&c->usecount);
 627         if (!d) {
 628                 err = -ENOMEM;
 629                 goto err_out;
 630         }
 631         d = debugfs_create_u32("rate", S_IRUGO, c->dentry, (u32 *)&c->rate);
 632         if (!d) {
 633                 err = -ENOMEM;
 634                 goto err_out;
 635         }
 636         d = debugfs_create_x32("flags", S_IRUGO, c->dentry, (u32 *)&c->flags);
 637         if (!d) {
 638                 err = -ENOMEM;
 639                 goto err_out;
 640         }
 641         return 0;
 642
 643 err_out:
 644         d = c->dentry;
 645         list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
 646                 debugfs_remove(child);
 647         debugfs_remove(c->dentry);
 648         return err;
 649 }
 650
 651 static int clk_debugfs_register(struct clk *c)
 652 {
 653         int err;
 654         struct clk *pa = c->parent;
 655
 656         if (pa && !pa->dentry) {
 657                 err = clk_debugfs_register(pa);
 658                 if (err)
 659                         return err;
 660         }
 661
 662         if (!c->dentry) {
 663                 err = clk_debugfs_register_one(c);
 664                 if (err)
 665                         return err;
 666         }
 667         return 0;
 668 }
 669
 670 static int __init clk_debugfs_init(void)
 671 {
 672         struct clk *c;
 673         struct dentry *d;
 674         int err;
 675
 676         d = debugfs_create_dir("clock", NULL);
 677         if (!d)
 678                 return -ENOMEM;
 679         clk_debugfs_root = d;
 680
 681         list_for_each_entry(c, &clock_list, node) {
 682                 err = clk_debugfs_register(c);
 683                 if (err)
 684                         goto err_out;
 685         }
 686         return 0;
 687 err_out:
 688         debugfs_remove_recursive(clk_debugfs_root);
 689         return err;
 690 }
 691 late_initcall(clk_debugfs_init);