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 pos, struct clk_rate_round_data *arg);
  80         void *arg;
  81 };
  82
  83 #define for_each_frequency(pos, r, freq)                        \
  84         for (pos = r->min, freq = r->func(pos, r->arg);         \
  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 int clk_rate_table_find(struct clk *clk,
 152                         struct cpufreq_frequency_table *freq_table,
 153                         unsigned long rate)
 154 {
 155         int i;
 156
 157         for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
 158                 unsigned long freq = freq_table[i].frequency;
 159
 160                 if (freq == CPUFREQ_ENTRY_INVALID)
 161                         continue;
 162
 163                 if (freq == rate)
 164                         return i;
 165         }
 166
 167         return -ENOENT;
 168 }
 169
 170 /* Used for clocks that always have same value as the parent clock */
 171 unsigned long followparent_recalc(struct clk *clk)
 172 {
 173         return clk->parent ? clk->parent->rate : 0;
 174 }
 175
 176 int clk_reparent(struct clk *child, struct clk *parent)
 177 {
 178         list_del_init(&child->sibling);
 179         if (parent)
 180                 list_add(&child->sibling, &parent->children);
 181         child->parent = parent;
 182
 183         /* now do the debugfs renaming to reattach the child
 184            to the proper parent */
 185
 186         return 0;
 187 }
 188
 189 /* Propagate rate to children */
 190 void propagate_rate(struct clk *tclk)
 191 {
 192         struct clk *clkp;
 193
 194         list_for_each_entry(clkp, &tclk->children, sibling) {
 195                 if (clkp->ops && clkp->ops->recalc)
 196                         clkp->rate = clkp->ops->recalc(clkp);
 197
 198                 propagate_rate(clkp);
 199         }
 200 }
 201
 202 static void __clk_disable(struct clk *clk)
 203 {
 204         if (WARN(!clk->usecount, "Trying to disable clock %p with 0 usecount\n",
 205                  clk))
 206                 return;
 207
 208         if (!(--clk->usecount)) {
 209                 if (likely(clk->ops && clk->ops->disable))
 210                         clk->ops->disable(clk);
 211                 if (likely(clk->parent))
 212                         __clk_disable(clk->parent);
 213         }
 214 }
 215
 216 void clk_disable(struct clk *clk)
 217 {
 218         unsigned long flags;
 219
 220         if (!clk)
 221                 return;
 222
 223         spin_lock_irqsave(&clock_lock, flags);
 224         __clk_disable(clk);
 225         spin_unlock_irqrestore(&clock_lock, flags);
 226 }
 227 EXPORT_SYMBOL_GPL(clk_disable);
 228
 229 static int __clk_enable(struct clk *clk)
 230 {
 231         int ret = 0;
 232
 233         if (clk->usecount++ == 0) {
 234                 if (clk->parent) {
 235                         ret = __clk_enable(clk->parent);
 236                         if (unlikely(ret))
 237                                 goto err;
 238                 }
 239
 240                 if (clk->ops && clk->ops->enable) {
 241                         ret = clk->ops->enable(clk);
 242                         if (ret) {
 243                                 if (clk->parent)
 244                                         __clk_disable(clk->parent);
 245                                 goto err;
 246                         }
 247                 }
 248         }
 249
 250         return ret;
 251 err:
 252         clk->usecount--;
 253         return ret;
 254 }
 255
 256 int clk_enable(struct clk *clk)
 257 {
 258         unsigned long flags;
 259         int ret;
 260
 261         if (!clk)
 262                 return -EINVAL;
 263
 264         spin_lock_irqsave(&clock_lock, flags);
 265         ret = __clk_enable(clk);
 266         spin_unlock_irqrestore(&clock_lock, flags);
 267
 268         return ret;
 269 }
 270 EXPORT_SYMBOL_GPL(clk_enable);
 271
 272 static LIST_HEAD(root_clks);
 273
 274 /**
 275  * recalculate_root_clocks - recalculate and propagate all root clocks
 276  *
 277  * Recalculates all root clocks (clocks with no parent), which if the
 278  * clock's .recalc is set correctly, should also propagate their rates.
 279  * Called at init.
 280  */
 281 void recalculate_root_clocks(void)
 282 {
 283         struct clk *clkp;
 284
 285         list_for_each_entry(clkp, &root_clks, sibling) {
 286                 if (clkp->ops && clkp->ops->recalc)
 287                         clkp->rate = clkp->ops->recalc(clkp);
 288                 propagate_rate(clkp);
 289         }
 290 }
 291
 292 static struct clk_mapping dummy_mapping;
 293
 294 static struct clk *lookup_root_clock(struct clk *clk)
 295 {
 296         while (clk->parent)
 297                 clk = clk->parent;
 298
 299         return clk;
 300 }
 301
 302 static int clk_establish_mapping(struct clk *clk)
 303 {
 304         struct clk_mapping *mapping = clk->mapping;
 305
 306         /*
 307          * Propagate mappings.
 308          */
 309         if (!mapping) {
 310                 struct clk *clkp;
 311
 312                 /*
 313                  * dummy mapping for root clocks with no specified ranges
 314                  */
 315                 if (!clk->parent) {
 316                         clk->mapping = &dummy_mapping;
 317                         return 0;
 318                 }
 319
 320                 /*
 321                  * If we're on a child clock and it provides no mapping of its
 322                  * own, inherit the mapping from its root clock.
 323                  */
 324                 clkp = lookup_root_clock(clk);
 325                 mapping = clkp->mapping;
 326                 BUG_ON(!mapping);
 327         }
 328
 329         /*
 330          * Establish initial mapping.
 331          */
 332         if (!mapping->base && mapping->phys) {
 333                 kref_init(&mapping->ref);
 334
 335                 mapping->base = ioremap_nocache(mapping->phys, mapping->len);
 336                 if (unlikely(!mapping->base))
 337                         return -ENXIO;
 338         } else if (mapping->base) {
 339                 /*
 340                  * Bump the refcount for an existing mapping
 341                  */
 342                 kref_get(&mapping->ref);
 343         }
 344
 345         clk->mapping = mapping;
 346         return 0;
 347 }
 348
 349 static void clk_destroy_mapping(struct kref *kref)
 350 {
 351         struct clk_mapping *mapping;
 352
 353         mapping = container_of(kref, struct clk_mapping, ref);
 354
 355         iounmap(mapping->base);
 356 }
 357
 358 static void clk_teardown_mapping(struct clk *clk)
 359 {
 360         struct clk_mapping *mapping = clk->mapping;
 361
 362         /* Nothing to do */
 363         if (mapping == &dummy_mapping)
 364                 return;
 365
 366         kref_put(&mapping->ref, clk_destroy_mapping);
 367         clk->mapping = NULL;
 368 }
 369
 370 int clk_register(struct clk *clk)
 371 {
 372         int ret;
 373
 374         if (clk == NULL || IS_ERR(clk))
 375                 return -EINVAL;
 376
 377         /*
 378          * trap out already registered clocks
 379          */
 380         if (clk->node.next || clk->node.prev)
 381                 return 0;
 382
 383         mutex_lock(&clock_list_sem);
 384
 385         INIT_LIST_HEAD(&clk->children);
 386         clk->usecount = 0;
 387
 388         ret = clk_establish_mapping(clk);
 389         if (unlikely(ret))
 390                 goto out_unlock;
 391
 392         if (clk->parent)
 393                 list_add(&clk->sibling, &clk->parent->children);
 394         else
 395                 list_add(&clk->sibling, &root_clks);
 396
 397         list_add(&clk->node, &clock_list);
 398         if (clk->ops && clk->ops->init)
 399                 clk->ops->init(clk);
 400
 401 out_unlock:
 402         mutex_unlock(&clock_list_sem);
 403
 404         return ret;
 405 }
 406 EXPORT_SYMBOL_GPL(clk_register);
 407
 408 void clk_unregister(struct clk *clk)
 409 {
 410         mutex_lock(&clock_list_sem);
 411         list_del(&clk->sibling);
 412         list_del(&clk->node);
 413         clk_teardown_mapping(clk);
 414         mutex_unlock(&clock_list_sem);
 415 }
 416 EXPORT_SYMBOL_GPL(clk_unregister);
 417
 418 void clk_enable_init_clocks(void)
 419 {
 420         struct clk *clkp;
 421
 422         list_for_each_entry(clkp, &clock_list, node)
 423                 if (clkp->flags & CLK_ENABLE_ON_INIT)
 424                         clk_enable(clkp);
 425 }
 426
 427 unsigned long clk_get_rate(struct clk *clk)
 428 {
 429         return clk->rate;
 430 }
 431 EXPORT_SYMBOL_GPL(clk_get_rate);
 432
 433 int clk_set_rate(struct clk *clk, unsigned long rate)
 434 {
 435         return clk_set_rate_ex(clk, rate, 0);
 436 }
 437 EXPORT_SYMBOL_GPL(clk_set_rate);
 438
 439 int clk_set_rate_ex(struct clk *clk, unsigned long rate, int algo_id)
 440 {
 441         int ret = -EOPNOTSUPP;
 442         unsigned long flags;
 443
 444         spin_lock_irqsave(&clock_lock, flags);
 445
 446         if (likely(clk->ops && clk->ops->set_rate)) {
 447                 ret = clk->ops->set_rate(clk, rate, algo_id);
 448                 if (ret != 0)
 449                         goto out_unlock;
 450         } else {
 451                 clk->rate = rate;
 452                 ret = 0;
 453         }
 454
 455         if (clk->ops && clk->ops->recalc)
 456                 clk->rate = clk->ops->recalc(clk);
 457
 458         propagate_rate(clk);
 459
 460 out_unlock:
 461         spin_unlock_irqrestore(&clock_lock, flags);
 462
 463         return ret;
 464 }
 465 EXPORT_SYMBOL_GPL(clk_set_rate_ex);
 466
 467 int clk_set_parent(struct clk *clk, struct clk *parent)
 468 {
 469         unsigned long flags;
 470         int ret = -EINVAL;
 471
 472         if (!parent || !clk)
 473                 return ret;
 474         if (clk->parent == parent)
 475                 return 0;
 476
 477         spin_lock_irqsave(&clock_lock, flags);
 478         if (clk->usecount == 0) {
 479                 if (clk->ops->set_parent)
 480                         ret = clk->ops->set_parent(clk, parent);
 481                 else
 482                         ret = clk_reparent(clk, parent);
 483
 484                 if (ret == 0) {
 485                         if (clk->ops->recalc)
 486                                 clk->rate = clk->ops->recalc(clk);
 487                         pr_debug("set parent of %p to %p (new rate %ld)\n",
 488                                  clk, clk->parent, clk->rate);
 489                         propagate_rate(clk);
 490                 }
 491         } else
 492                 ret = -EBUSY;
 493         spin_unlock_irqrestore(&clock_lock, flags);
 494
 495         return ret;
 496 }
 497 EXPORT_SYMBOL_GPL(clk_set_parent);
 498
 499 struct clk *clk_get_parent(struct clk *clk)
 500 {
 501         return clk->parent;
 502 }
 503 EXPORT_SYMBOL_GPL(clk_get_parent);
 504
 505 long clk_round_rate(struct clk *clk, unsigned long rate)
 506 {
 507         if (likely(clk->ops && clk->ops->round_rate)) {
 508                 unsigned long flags, rounded;
 509
 510                 spin_lock_irqsave(&clock_lock, flags);
 511                 rounded = clk->ops->round_rate(clk, rate);
 512                 spin_unlock_irqrestore(&clock_lock, flags);
 513
 514                 return rounded;
 515         }
 516
 517         return clk_get_rate(clk);
 518 }
 519 EXPORT_SYMBOL_GPL(clk_round_rate);
 520
 521 #ifdef CONFIG_PM
 522 static int clks_sysdev_suspend(struct sys_device *dev, pm_message_t state)
 523 {
 524         static pm_message_t prev_state;
 525         struct clk *clkp;
 526
 527         switch (state.event) {
 528         case PM_EVENT_ON:
 529                 /* Resumeing from hibernation */
 530                 if (prev_state.event != PM_EVENT_FREEZE)
 531                         break;
 532
 533                 list_for_each_entry(clkp, &clock_list, node) {
 534                         if (likely(clkp->ops)) {
 535                                 unsigned long rate = clkp->rate;
 536
 537                                 if (likely(clkp->ops->set_parent))
 538                                         clkp->ops->set_parent(clkp,
 539                                                 clkp->parent);
 540                                 if (likely(clkp->ops->set_rate))
 541                                         clkp->ops->set_rate(clkp,
 542                                                 rate, NO_CHANGE);
 543                                 else if (likely(clkp->ops->recalc))
 544                                         clkp->rate = clkp->ops->recalc(clkp);
 545                         }
 546                 }
 547                 break;
 548         case PM_EVENT_FREEZE:
 549                 break;
 550         case PM_EVENT_SUSPEND:
 551                 break;
 552         }
 553
 554         prev_state = state;
 555         return 0;
 556 }
 557
 558 static int clks_sysdev_resume(struct sys_device *dev)
 559 {
 560         return clks_sysdev_suspend(dev, PMSG_ON);
 561 }
 562
 563 static struct sysdev_class clks_sysdev_class = {
 564         .name = "clks",
 565 };
 566
 567 static struct sysdev_driver clks_sysdev_driver = {
 568         .suspend = clks_sysdev_suspend,
 569         .resume = clks_sysdev_resume,
 570 };
 571
 572 static struct sys_device clks_sysdev_dev = {
 573         .cls = &clks_sysdev_class,
 574 };
 575
 576 static int __init clk_sysdev_init(void)
 577 {
 578         sysdev_class_register(&clks_sysdev_class);
 579         sysdev_driver_register(&clks_sysdev_class, &clks_sysdev_driver);
 580         sysdev_register(&clks_sysdev_dev);
 581
 582         return 0;
 583 }
 584 subsys_initcall(clk_sysdev_init);
 585 #endif
 586
 587 /*
 588  *      debugfs support to trace clock tree hierarchy and attributes
 589  */
 590 static struct dentry *clk_debugfs_root;
 591
 592 static int clk_debugfs_register_one(struct clk *c)
 593 {
 594         int err;
 595         struct dentry *d, *child, *child_tmp;
 596         struct clk *pa = c->parent;
 597         char s[255];
 598         char *p = s;
 599
 600         p += sprintf(p, "%p", c);
 601         d = debugfs_create_dir(s, pa ? pa->dentry : clk_debugfs_root);
 602         if (!d)
 603                 return -ENOMEM;
 604         c->dentry = d;
 605
 606         d = debugfs_create_u8("usecount", S_IRUGO, c->dentry, (u8 *)&c->usecount);
 607         if (!d) {
 608                 err = -ENOMEM;
 609                 goto err_out;
 610         }
 611         d = debugfs_create_u32("rate", S_IRUGO, c->dentry, (u32 *)&c->rate);
 612         if (!d) {
 613                 err = -ENOMEM;
 614                 goto err_out;
 615         }
 616         d = debugfs_create_x32("flags", S_IRUGO, c->dentry, (u32 *)&c->flags);
 617         if (!d) {
 618                 err = -ENOMEM;
 619                 goto err_out;
 620         }
 621         return 0;
 622
 623 err_out:
 624         d = c->dentry;
 625         list_for_each_entry_safe(child, child_tmp, &d->d_subdirs, d_u.d_child)
 626                 debugfs_remove(child);
 627         debugfs_remove(c->dentry);
 628         return err;
 629 }
 630
 631 static int clk_debugfs_register(struct clk *c)
 632 {
 633         int err;
 634         struct clk *pa = c->parent;
 635
 636         if (pa && !pa->dentry) {
 637                 err = clk_debugfs_register(pa);
 638                 if (err)
 639                         return err;
 640         }
 641
 642         if (!c->dentry) {
 643                 err = clk_debugfs_register_one(c);
 644                 if (err)
 645                         return err;
 646         }
 647         return 0;
 648 }
 649
 650 static int __init clk_debugfs_init(void)
 651 {
 652         struct clk *c;
 653         struct dentry *d;
 654         int err;
 655
 656         d = debugfs_create_dir("clock", NULL);
 657         if (!d)
 658                 return -ENOMEM;
 659         clk_debugfs_root = d;
 660
 661         list_for_each_entry(c, &clock_list, node) {
 662                 err = clk_debugfs_register(c);
 663                 if (err)
 664                         goto err_out;
 665         }
 666         return 0;
 667 err_out:
 668         debugfs_remove_recursive(clk_debugfs_root);
 669         return err;
 670 }
 671 late_initcall(clk_debugfs_init);