kernel/drivers/sh/clk/core.c

   1 /*
   2  * 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/syscore_ops.h>
  25 #include <linux/seq_file.h>
  26 #include <linux/err.h>
  27 #include <linux/io.h>
  28 #include <linux/cpufreq.h>
  29 #include <linux/clk.h>
  30 #include <linux/sh_clk.h>
  31
  32 static LIST_HEAD(clock_list);
  33 static DEFINE_SPINLOCK(clock_lock);
  34 static DEFINE_MUTEX(clock_list_sem);
  35
  36 /* clock disable operations are not passed on to hardware during boot */
  37 static int allow_disable;
  38
  39 void clk_rate_table_build(struct clk *clk,
  40                           struct cpufreq_frequency_table *freq_table,
  41                           int nr_freqs,
  42                           struct clk_div_mult_table *src_table,
  43                           unsigned long *bitmap)
  44 {
  45         unsigned long mult, div;
  46         unsigned long freq;
  47         int i;
  48
  49         clk->nr_freqs = nr_freqs;
  50
  51         for (i = 0; i < nr_freqs; i++) {
  52                 div = 1;
  53                 mult = 1;
  54
  55                 if (src_table->divisors && i < src_table->nr_divisors)
  56                         div = src_table->divisors[i];
  57
  58                 if (src_table->multipliers && i < src_table->nr_multipliers)
  59                         mult = src_table->multipliers[i];
  60
  61                 if (!div || !mult || (bitmap && !test_bit(i, bitmap)))
  62                         freq = CPUFREQ_ENTRY_INVALID;
  63                 else
  64                         freq = clk->parent->rate * mult / div;
  65
  66                 freq_table[i].driver_data = i;
  67                 freq_table[i].frequency = freq;
  68         }
  69
  70         /* Termination entry */
  71         freq_table[i].driver_data = i;
  72         freq_table[i].frequency = CPUFREQ_TABLE_END;
  73 }
  74
  75 struct clk_rate_round_data;
  76
  77 struct clk_rate_round_data {
  78         unsigned long rate;
  79         unsigned int min, max;
  80         long (*func)(unsigned int, struct clk_rate_round_data *);
  81         void *arg;
  82 };
  83
  84 #define for_each_frequency(pos, r, freq)                        \
  85         for (pos = r->min, freq = r->func(pos, r);              \
  86              pos <= r->max; pos++, freq = r->func(pos, r))      \
  87                 if (unlikely(freq == 0))                        \
  88                         ;                                       \
  89                 else
  90
  91 static long clk_rate_round_helper(struct clk_rate_round_data *rounder)
  92 {
  93         unsigned long rate_error, rate_error_prev = ~0UL;
  94         unsigned long highest, lowest, freq;
  95         long rate_best_fit = -ENOENT;
  96         int i;
  97
  98         highest = 0;
  99         lowest = ~0UL;
 100
 101         for_each_frequency(i, rounder, freq) {
 102                 if (freq > highest)
 103                         highest = freq;
 104                 if (freq < lowest)
 105                         lowest = freq;
 106
 107                 rate_error = abs(freq - rounder->rate);
 108                 if (rate_error < rate_error_prev) {
 109                         rate_best_fit = freq;
 110                         rate_error_prev = rate_error;
 111                 }
 112
 113                 if (rate_error == 0)
 114                         break;
 115         }
 116
 117         if (rounder->rate >= highest)
 118                 rate_best_fit = highest;
 119         if (rounder->rate <= lowest)
 120                 rate_best_fit = lowest;
 121
 122         return rate_best_fit;
 123 }
 124
 125 static long clk_rate_table_iter(unsigned int pos,
 126                                 struct clk_rate_round_data *rounder)
 127 {
 128         struct cpufreq_frequency_table *freq_table = rounder->arg;
 129         unsigned long freq = freq_table[pos].frequency;
 130
 131         if (freq == CPUFREQ_ENTRY_INVALID)
 132                 freq = 0;
 133
 134         return freq;
 135 }
 136
 137 long clk_rate_table_round(struct clk *clk,
 138                           struct cpufreq_frequency_table *freq_table,
 139                           unsigned long rate)
 140 {
 141         struct clk_rate_round_data table_round = {
 142                 .min    = 0,
 143                 .max    = clk->nr_freqs - 1,
 144                 .func   = clk_rate_table_iter,
 145                 .arg    = freq_table,
 146                 .rate   = rate,
 147         };
 148
 149         if (clk->nr_freqs < 1)
 150                 return -ENOSYS;
 151
 152         return clk_rate_round_helper(&table_round);
 153 }
 154
 155 static long clk_rate_div_range_iter(unsigned int pos,
 156                                     struct clk_rate_round_data *rounder)
 157 {
 158         return clk_get_rate(rounder->arg) / pos;
 159 }
 160
 161 long clk_rate_div_range_round(struct clk *clk, unsigned int div_min,
 162                               unsigned int div_max, unsigned long rate)
 163 {
 164         struct clk_rate_round_data div_range_round = {
 165                 .min    = div_min,
 166                 .max    = div_max,
 167                 .func   = clk_rate_div_range_iter,
 168                 .arg    = clk_get_parent(clk),
 169                 .rate   = rate,
 170         };
 171
 172         return clk_rate_round_helper(&div_range_round);
 173 }
 174
 175 static long clk_rate_mult_range_iter(unsigned int pos,
 176                                       struct clk_rate_round_data *rounder)
 177 {
 178         return clk_get_rate(rounder->arg) * pos;
 179 }
 180
 181 long clk_rate_mult_range_round(struct clk *clk, unsigned int mult_min,
 182                                unsigned int mult_max, unsigned long rate)
 183 {
 184         struct clk_rate_round_data mult_range_round = {
 185                 .min    = mult_min,
 186                 .max    = mult_max,
 187                 .func   = clk_rate_mult_range_iter,
 188                 .arg    = clk_get_parent(clk),
 189                 .rate   = rate,
 190         };
 191
 192         return clk_rate_round_helper(&mult_range_round);
 193 }
 194
 195 int clk_rate_table_find(struct clk *clk,
 196                         struct cpufreq_frequency_table *freq_table,
 197                         unsigned long rate)
 198 {
 199         struct cpufreq_frequency_table *pos;
 200
 201         cpufreq_for_each_valid_entry(pos, freq_table)
 202                 if (pos->frequency == rate)
 203                         return pos - freq_table;
 204
 205         return -ENOENT;
 206 }
 207
 208 /* Used for clocks that always have same value as the parent clock */
 209 unsigned long followparent_recalc(struct clk *clk)
 210 {
 211         return clk->parent ? clk->parent->rate : 0;
 212 }
 213
 214 int clk_reparent(struct clk *child, struct clk *parent)
 215 {
 216         list_del_init(&child->sibling);
 217         if (parent)
 218                 list_add(&child->sibling, &parent->children);
 219         child->parent = parent;
 220
 221         return 0;
 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->ops && clkp->ops->recalc)
 231                         clkp->rate = clkp->ops->recalc(clkp);
 232
 233                 propagate_rate(clkp);
 234         }
 235 }
 236
 237 static void __clk_disable(struct clk *clk)
 238 {
 239         if (WARN(!clk->usecount, "Trying to disable clock %p with 0 usecount\n",
 240                  clk))
 241                 return;
 242
 243         if (!(--clk->usecount)) {
 244                 if (likely(allow_disable && clk->ops && clk->ops->disable))
 245                         clk->ops->disable(clk);
 246                 if (likely(clk->parent))
 247                         __clk_disable(clk->parent);
 248         }
 249 }
 250
 251 void clk_disable(struct clk *clk)
 252 {
 253         unsigned long flags;
 254
 255         if (!clk)
 256                 return;
 257
 258         spin_lock_irqsave(&clock_lock, flags);
 259         __clk_disable(clk);
 260         spin_unlock_irqrestore(&clock_lock, flags);
 261 }
 262 EXPORT_SYMBOL_GPL(clk_disable);
 263
 264 static int __clk_enable(struct clk *clk)
 265 {
 266         int ret = 0;
 267
 268         if (clk->usecount++ == 0) {
 269                 if (clk->parent) {
 270                         ret = __clk_enable(clk->parent);
 271                         if (unlikely(ret))
 272                                 goto err;
 273                 }
 274
 275                 if (clk->ops && clk->ops->enable) {
 276                         ret = clk->ops->enable(clk);
 277                         if (ret) {
 278                                 if (clk->parent)
 279                                         __clk_disable(clk->parent);
 280                                 goto err;
 281                         }
 282                 }
 283         }
 284
 285         return ret;
 286 err:
 287         clk->usecount--;
 288         return ret;
 289 }
 290
 291 int clk_enable(struct clk *clk)
 292 {
 293         unsigned long flags;
 294         int ret;
 295
 296         if (!clk)
 297                 return -EINVAL;
 298
 299         spin_lock_irqsave(&clock_lock, flags);
 300         ret = __clk_enable(clk);
 301         spin_unlock_irqrestore(&clock_lock, flags);
 302
 303         return ret;
 304 }
 305 EXPORT_SYMBOL_GPL(clk_enable);
 306
 307 static LIST_HEAD(root_clks);
 308
 309 /**
 310  * recalculate_root_clocks - recalculate and propagate all root clocks
 311  *
 312  * Recalculates all root clocks (clocks with no parent), which if the
 313  * clock's .recalc is set correctly, should also propagate their rates.
 314  * Called at init.
 315  */
 316 void recalculate_root_clocks(void)
 317 {
 318         struct clk *clkp;
 319
 320         list_for_each_entry(clkp, &root_clks, sibling) {
 321                 if (clkp->ops && clkp->ops->recalc)
 322                         clkp->rate = clkp->ops->recalc(clkp);
 323                 propagate_rate(clkp);
 324         }
 325 }
 326
 327 static struct clk_mapping dummy_mapping;
 328
 329 static struct clk *lookup_root_clock(struct clk *clk)
 330 {
 331         while (clk->parent)
 332                 clk = clk->parent;
 333
 334         return clk;
 335 }
 336
 337 static int clk_establish_mapping(struct clk *clk)
 338 {
 339         struct clk_mapping *mapping = clk->mapping;
 340
 341         /*
 342          * Propagate mappings.
 343          */
 344         if (!mapping) {
 345                 struct clk *clkp;
 346
 347                 /*
 348                  * dummy mapping for root clocks with no specified ranges
 349                  */
 350                 if (!clk->parent) {
 351                         clk->mapping = &dummy_mapping;
 352                         goto out;
 353                 }
 354
 355                 /*
 356                  * If we're on a child clock and it provides no mapping of its
 357                  * own, inherit the mapping from its root clock.
 358                  */
 359                 clkp = lookup_root_clock(clk);
 360                 mapping = clkp->mapping;
 361                 BUG_ON(!mapping);
 362         }
 363
 364         /*
 365          * Establish initial mapping.
 366          */
 367         if (!mapping->base && mapping->phys) {
 368                 kref_init(&mapping->ref);
 369
 370                 mapping->base = ioremap_nocache(mapping->phys, mapping->len);
 371                 if (unlikely(!mapping->base))
 372                         return -ENXIO;
 373         } else if (mapping->base) {
 374                 /*
 375                  * Bump the refcount for an existing mapping
 376                  */
 377                 kref_get(&mapping->ref);
 378         }
 379
 380         clk->mapping = mapping;
 381 out:
 382         clk->mapped_reg = clk->mapping->base;
 383         clk->mapped_reg += (phys_addr_t)clk->enable_reg - clk->mapping->phys;
 384         return 0;
 385 }
 386
 387 static void clk_destroy_mapping(struct kref *kref)
 388 {
 389         struct clk_mapping *mapping;
 390
 391         mapping = container_of(kref, struct clk_mapping, ref);
 392
 393         iounmap(mapping->base);
 394 }
 395
 396 static void clk_teardown_mapping(struct clk *clk)
 397 {
 398         struct clk_mapping *mapping = clk->mapping;
 399
 400         /* Nothing to do */
 401         if (mapping == &dummy_mapping)
 402                 goto out;
 403
 404         kref_put(&mapping->ref, clk_destroy_mapping);
 405         clk->mapping = NULL;
 406 out:
 407         clk->mapped_reg = NULL;
 408 }
 409
 410 int clk_register(struct clk *clk)
 411 {
 412         int ret;
 413
 414         if (IS_ERR_OR_NULL(clk))
 415                 return -EINVAL;
 416
 417         /*
 418          * trap out already registered clocks
 419          */
 420         if (clk->node.next || clk->node.prev)
 421                 return 0;
 422
 423         mutex_lock(&clock_list_sem);
 424
 425         INIT_LIST_HEAD(&clk->children);
 426         clk->usecount = 0;
 427
 428         ret = clk_establish_mapping(clk);
 429         if (unlikely(ret))
 430                 goto out_unlock;
 431
 432         if (clk->parent)
 433                 list_add(&clk->sibling, &clk->parent->children);
 434         else
 435                 list_add(&clk->sibling, &root_clks);
 436
 437         list_add(&clk->node, &clock_list);
 438
 439 #ifdef CONFIG_SH_CLK_CPG_LEGACY
 440         if (clk->ops && clk->ops->init)
 441                 clk->ops->init(clk);
 442 #endif
 443
 444 out_unlock:
 445         mutex_unlock(&clock_list_sem);
 446
 447         return ret;
 448 }
 449 EXPORT_SYMBOL_GPL(clk_register);
 450
 451 void clk_unregister(struct clk *clk)
 452 {
 453         mutex_lock(&clock_list_sem);
 454         list_del(&clk->sibling);
 455         list_del(&clk->node);
 456         clk_teardown_mapping(clk);
 457         mutex_unlock(&clock_list_sem);
 458 }
 459 EXPORT_SYMBOL_GPL(clk_unregister);
 460
 461 void clk_enable_init_clocks(void)
 462 {
 463         struct clk *clkp;
 464
 465         list_for_each_entry(clkp, &clock_list, node)
 466                 if (clkp->flags & CLK_ENABLE_ON_INIT)
 467                         clk_enable(clkp);
 468 }
 469
 470 unsigned long clk_get_rate(struct clk *clk)
 471 {
 472         return clk->rate;
 473 }
 474 EXPORT_SYMBOL_GPL(clk_get_rate);
 475
 476 int clk_set_rate(struct clk *clk, unsigned long rate)
 477 {
 478         int ret = -EOPNOTSUPP;
 479         unsigned long flags;
 480
 481         spin_lock_irqsave(&clock_lock, flags);
 482
 483         if (likely(clk->ops && clk->ops->set_rate)) {
 484                 ret = clk->ops->set_rate(clk, rate);
 485                 if (ret != 0)
 486                         goto out_unlock;
 487         } else {
 488                 clk->rate = rate;
 489                 ret = 0;
 490         }
 491
 492         if (clk->ops && clk->ops->recalc)
 493                 clk->rate = clk->ops->recalc(clk);
 494
 495         propagate_rate(clk);
 496
 497 out_unlock:
 498         spin_unlock_irqrestore(&clock_lock, flags);
 499
 500         return ret;
 501 }
 502 EXPORT_SYMBOL_GPL(clk_set_rate);
 503
 504 int clk_set_parent(struct clk *clk, struct clk *parent)
 505 {
 506         unsigned long flags;
 507         int ret = -EINVAL;
 508
 509         if (!parent || !clk)
 510                 return ret;
 511         if (clk->parent == parent)
 512                 return 0;
 513
 514         spin_lock_irqsave(&clock_lock, flags);
 515         if (clk->usecount == 0) {
 516                 if (clk->ops->set_parent)
 517                         ret = clk->ops->set_parent(clk, parent);
 518                 else
 519                         ret = clk_reparent(clk, parent);
 520
 521                 if (ret == 0) {
 522                         if (clk->ops->recalc)
 523                                 clk->rate = clk->ops->recalc(clk);
 524                         pr_debug("set parent of %p to %p (new rate %ld)\n",
 525                                  clk, clk->parent, clk->rate);
 526                         propagate_rate(clk);
 527                 }
 528         } else
 529                 ret = -EBUSY;
 530         spin_unlock_irqrestore(&clock_lock, flags);
 531
 532         return ret;
 533 }
 534 EXPORT_SYMBOL_GPL(clk_set_parent);
 535
 536 struct clk *clk_get_parent(struct clk *clk)
 537 {
 538         return clk->parent;
 539 }
 540 EXPORT_SYMBOL_GPL(clk_get_parent);
 541
 542 long clk_round_rate(struct clk *clk, unsigned long rate)
 543 {
 544         if (likely(clk->ops && clk->ops->round_rate)) {
 545                 unsigned long flags, rounded;
 546
 547                 spin_lock_irqsave(&clock_lock, flags);
 548                 rounded = clk->ops->round_rate(clk, rate);
 549                 spin_unlock_irqrestore(&clock_lock, flags);
 550
 551                 return rounded;
 552         }
 553
 554         return clk_get_rate(clk);
 555 }
 556 EXPORT_SYMBOL_GPL(clk_round_rate);
 557
 558 long clk_round_parent(struct clk *clk, unsigned long target,
 559                       unsigned long *best_freq, unsigned long *parent_freq,
 560                       unsigned int div_min, unsigned int div_max)
 561 {
 562         struct cpufreq_frequency_table *freq, *best = NULL;
 563         unsigned long error = ULONG_MAX, freq_high, freq_low, div;
 564         struct clk *parent = clk_get_parent(clk);
 565
 566         if (!parent) {
 567                 *parent_freq = 0;
 568                 *best_freq = clk_round_rate(clk, target);
 569                 return abs(target - *best_freq);
 570         }
 571
 572         cpufreq_for_each_valid_entry(freq, parent->freq_table) {
 573                 if (unlikely(freq->frequency / target <= div_min - 1)) {
 574                         unsigned long freq_max;
 575
 576                         freq_max = (freq->frequency + div_min / 2) / div_min;
 577                         if (error > target - freq_max) {
 578                                 error = target - freq_max;
 579                                 best = freq;
 580                                 if (best_freq)
 581                                         *best_freq = freq_max;
 582                         }
 583
 584                         pr_debug("too low freq %u, error %lu\n", freq->frequency,
 585                                  target - freq_max);
 586
 587                         if (!error)
 588                                 break;
 589
 590                         continue;
 591                 }
 592
 593                 if (unlikely(freq->frequency / target >= div_max)) {
 594                         unsigned long freq_min;
 595
 596                         freq_min = (freq->frequency + div_max / 2) / div_max;
 597                         if (error > freq_min - target) {
 598                                 error = freq_min - target;
 599                                 best = freq;
 600                                 if (best_freq)
 601                                         *best_freq = freq_min;
 602                         }
 603
 604                         pr_debug("too high freq %u, error %lu\n", freq->frequency,
 605                                  freq_min - target);
 606
 607                         if (!error)
 608                                 break;
 609
 610                         continue;
 611                 }
 612
 613                 div = freq->frequency / target;
 614                 freq_high = freq->frequency / div;
 615                 freq_low = freq->frequency / (div + 1);
 616
 617                 if (freq_high - target < error) {
 618                         error = freq_high - target;
 619                         best = freq;
 620                         if (best_freq)
 621                                 *best_freq = freq_high;
 622                 }
 623
 624                 if (target - freq_low < error) {
 625                         error = target - freq_low;
 626                         best = freq;
 627                         if (best_freq)
 628                                 *best_freq = freq_low;
 629                 }
 630
 631                 pr_debug("%u / %lu = %lu, / %lu = %lu, best %lu, parent %u\n",
 632                          freq->frequency, div, freq_high, div + 1, freq_low,
 633                          *best_freq, best->frequency);
 634
 635                 if (!error)
 636                         break;
 637         }
 638
 639         if (parent_freq)
 640                 *parent_freq = best->frequency;
 641
 642         return error;
 643 }
 644 EXPORT_SYMBOL_GPL(clk_round_parent);
 645
 646 #ifdef CONFIG_PM
 647 static void clks_core_resume(void)
 648 {
 649         struct clk *clkp;
 650
 651         list_for_each_entry(clkp, &clock_list, node) {
 652                 if (likely(clkp->usecount && clkp->ops)) {
 653                         unsigned long rate = clkp->rate;
 654
 655                         if (likely(clkp->ops->set_parent))
 656                                 clkp->ops->set_parent(clkp,
 657                                         clkp->parent);
 658                         if (likely(clkp->ops->set_rate))
 659                                 clkp->ops->set_rate(clkp, rate);
 660                         else if (likely(clkp->ops->recalc))
 661                                 clkp->rate = clkp->ops->recalc(clkp);
 662                 }
 663         }
 664 }
 665
 666 static struct syscore_ops clks_syscore_ops = {
 667         .resume = clks_core_resume,
 668 };
 669
 670 static int __init clk_syscore_init(void)
 671 {
 672         register_syscore_ops(&clks_syscore_ops);
 673
 674         return 0;
 675 }
 676 subsys_initcall(clk_syscore_init);
 677 #endif
 678
 679 static int __init clk_late_init(void)
 680 {
 681         unsigned long flags;
 682         struct clk *clk;
 683
 684         /* disable all clocks with zero use count */
 685         mutex_lock(&clock_list_sem);
 686         spin_lock_irqsave(&clock_lock, flags);
 687
 688         list_for_each_entry(clk, &clock_list, node)
 689                 if (!clk->usecount && clk->ops && clk->ops->disable)
 690                         clk->ops->disable(clk);
 691
 692         /* from now on allow clock disable operations */
 693         allow_disable = 1;
 694
 695         spin_unlock_irqrestore(&clock_lock, flags);
 696         mutex_unlock(&clock_list_sem);
 697         return 0;
 698 }
 699 late_initcall(clk_late_init);