linux/drivers/sh/clk/core.c
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   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
  32static LIST_HEAD(clock_list);
  33static DEFINE_SPINLOCK(clock_lock);
  34static DEFINE_MUTEX(clock_list_sem);
  35
  36/* clock disable operations are not passed on to hardware during boot */
  37static int allow_disable;
  38
  39void 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
  75struct clk_rate_round_data;
  76
  77struct 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
  91static 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
 125static 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
 137long 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
 155static 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
 161long 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
 175static 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
 181long 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
 195int 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        int idx;
 201
 202        cpufreq_for_each_valid_entry_idx(pos, freq_table, idx)
 203                if (pos->frequency == rate)
 204                        return idx;
 205
 206        return -ENOENT;
 207}
 208
 209/* Used for clocks that always have same value as the parent clock */
 210unsigned long followparent_recalc(struct clk *clk)
 211{
 212        return clk->parent ? clk->parent->rate : 0;
 213}
 214
 215int clk_reparent(struct clk *child, struct clk *parent)
 216{
 217        list_del_init(&child->sibling);
 218        if (parent)
 219                list_add(&child->sibling, &parent->children);
 220        child->parent = parent;
 221
 222        return 0;
 223}
 224
 225/* Propagate rate to children */
 226void propagate_rate(struct clk *tclk)
 227{
 228        struct clk *clkp;
 229
 230        list_for_each_entry(clkp, &tclk->children, sibling) {
 231                if (clkp->ops && clkp->ops->recalc)
 232                        clkp->rate = clkp->ops->recalc(clkp);
 233
 234                propagate_rate(clkp);
 235        }
 236}
 237
 238static void __clk_disable(struct clk *clk)
 239{
 240        if (WARN(!clk->usecount, "Trying to disable clock %p with 0 usecount\n",
 241                 clk))
 242                return;
 243
 244        if (!(--clk->usecount)) {
 245                if (likely(allow_disable && clk->ops && clk->ops->disable))
 246                        clk->ops->disable(clk);
 247                if (likely(clk->parent))
 248                        __clk_disable(clk->parent);
 249        }
 250}
 251
 252void clk_disable(struct clk *clk)
 253{
 254        unsigned long flags;
 255
 256        if (!clk)
 257                return;
 258
 259        spin_lock_irqsave(&clock_lock, flags);
 260        __clk_disable(clk);
 261        spin_unlock_irqrestore(&clock_lock, flags);
 262}
 263EXPORT_SYMBOL_GPL(clk_disable);
 264
 265static int __clk_enable(struct clk *clk)
 266{
 267        int ret = 0;
 268
 269        if (clk->usecount++ == 0) {
 270                if (clk->parent) {
 271                        ret = __clk_enable(clk->parent);
 272                        if (unlikely(ret))
 273                                goto err;
 274                }
 275
 276                if (clk->ops && clk->ops->enable) {
 277                        ret = clk->ops->enable(clk);
 278                        if (ret) {
 279                                if (clk->parent)
 280                                        __clk_disable(clk->parent);
 281                                goto err;
 282                        }
 283                }
 284        }
 285
 286        return ret;
 287err:
 288        clk->usecount--;
 289        return ret;
 290}
 291
 292int clk_enable(struct clk *clk)
 293{
 294        unsigned long flags;
 295        int ret;
 296
 297        if (!clk)
 298                return -EINVAL;
 299
 300        spin_lock_irqsave(&clock_lock, flags);
 301        ret = __clk_enable(clk);
 302        spin_unlock_irqrestore(&clock_lock, flags);
 303
 304        return ret;
 305}
 306EXPORT_SYMBOL_GPL(clk_enable);
 307
 308static LIST_HEAD(root_clks);
 309
 310/**
 311 * recalculate_root_clocks - recalculate and propagate all root clocks
 312 *
 313 * Recalculates all root clocks (clocks with no parent), which if the
 314 * clock's .recalc is set correctly, should also propagate their rates.
 315 * Called at init.
 316 */
 317void recalculate_root_clocks(void)
 318{
 319        struct clk *clkp;
 320
 321        list_for_each_entry(clkp, &root_clks, sibling) {
 322                if (clkp->ops && clkp->ops->recalc)
 323                        clkp->rate = clkp->ops->recalc(clkp);
 324                propagate_rate(clkp);
 325        }
 326}
 327
 328static struct clk_mapping dummy_mapping;
 329
 330static struct clk *lookup_root_clock(struct clk *clk)
 331{
 332        while (clk->parent)
 333                clk = clk->parent;
 334
 335        return clk;
 336}
 337
 338static int clk_establish_mapping(struct clk *clk)
 339{
 340        struct clk_mapping *mapping = clk->mapping;
 341
 342        /*
 343         * Propagate mappings.
 344         */
 345        if (!mapping) {
 346                struct clk *clkp;
 347
 348                /*
 349                 * dummy mapping for root clocks with no specified ranges
 350                 */
 351                if (!clk->parent) {
 352                        clk->mapping = &dummy_mapping;
 353                        goto out;
 354                }
 355
 356                /*
 357                 * If we're on a child clock and it provides no mapping of its
 358                 * own, inherit the mapping from its root clock.
 359                 */
 360                clkp = lookup_root_clock(clk);
 361                mapping = clkp->mapping;
 362                BUG_ON(!mapping);
 363        }
 364
 365        /*
 366         * Establish initial mapping.
 367         */
 368        if (!mapping->base && mapping->phys) {
 369                kref_init(&mapping->ref);
 370
 371                mapping->base = ioremap_nocache(mapping->phys, mapping->len);
 372                if (unlikely(!mapping->base))
 373                        return -ENXIO;
 374        } else if (mapping->base) {
 375                /*
 376                 * Bump the refcount for an existing mapping
 377                 */
 378                kref_get(&mapping->ref);
 379        }
 380
 381        clk->mapping = mapping;
 382out:
 383        clk->mapped_reg = clk->mapping->base;
 384        clk->mapped_reg += (phys_addr_t)clk->enable_reg - clk->mapping->phys;
 385        return 0;
 386}
 387
 388static void clk_destroy_mapping(struct kref *kref)
 389{
 390        struct clk_mapping *mapping;
 391
 392        mapping = container_of(kref, struct clk_mapping, ref);
 393
 394        iounmap(mapping->base);
 395}
 396
 397static void clk_teardown_mapping(struct clk *clk)
 398{
 399        struct clk_mapping *mapping = clk->mapping;
 400
 401        /* Nothing to do */
 402        if (mapping == &dummy_mapping)
 403                goto out;
 404
 405        kref_put(&mapping->ref, clk_destroy_mapping);
 406        clk->mapping = NULL;
 407out:
 408        clk->mapped_reg = NULL;
 409}
 410
 411int clk_register(struct clk *clk)
 412{
 413        int ret;
 414
 415        if (IS_ERR_OR_NULL(clk))
 416                return -EINVAL;
 417
 418        /*
 419         * trap out already registered clocks
 420         */
 421        if (clk->node.next || clk->node.prev)
 422                return 0;
 423
 424        mutex_lock(&clock_list_sem);
 425
 426        INIT_LIST_HEAD(&clk->children);
 427        clk->usecount = 0;
 428
 429        ret = clk_establish_mapping(clk);
 430        if (unlikely(ret))
 431                goto out_unlock;
 432
 433        if (clk->parent)
 434                list_add(&clk->sibling, &clk->parent->children);
 435        else
 436                list_add(&clk->sibling, &root_clks);
 437
 438        list_add(&clk->node, &clock_list);
 439
 440#ifdef CONFIG_SH_CLK_CPG_LEGACY
 441        if (clk->ops && clk->ops->init)
 442                clk->ops->init(clk);
 443#endif
 444
 445out_unlock:
 446        mutex_unlock(&clock_list_sem);
 447
 448        return ret;
 449}
 450EXPORT_SYMBOL_GPL(clk_register);
 451
 452void clk_unregister(struct clk *clk)
 453{
 454        mutex_lock(&clock_list_sem);
 455        list_del(&clk->sibling);
 456        list_del(&clk->node);
 457        clk_teardown_mapping(clk);
 458        mutex_unlock(&clock_list_sem);
 459}
 460EXPORT_SYMBOL_GPL(clk_unregister);
 461
 462void clk_enable_init_clocks(void)
 463{
 464        struct clk *clkp;
 465
 466        list_for_each_entry(clkp, &clock_list, node)
 467                if (clkp->flags & CLK_ENABLE_ON_INIT)
 468                        clk_enable(clkp);
 469}
 470
 471unsigned long clk_get_rate(struct clk *clk)
 472{
 473        if (!clk)
 474                return 0;
 475
 476        return clk->rate;
 477}
 478EXPORT_SYMBOL_GPL(clk_get_rate);
 479
 480int clk_set_rate(struct clk *clk, unsigned long rate)
 481{
 482        int ret = -EOPNOTSUPP;
 483        unsigned long flags;
 484
 485        if (!clk)
 486                return 0;
 487
 488        spin_lock_irqsave(&clock_lock, flags);
 489
 490        if (likely(clk->ops && clk->ops->set_rate)) {
 491                ret = clk->ops->set_rate(clk, rate);
 492                if (ret != 0)
 493                        goto out_unlock;
 494        } else {
 495                clk->rate = rate;
 496                ret = 0;
 497        }
 498
 499        if (clk->ops && clk->ops->recalc)
 500                clk->rate = clk->ops->recalc(clk);
 501
 502        propagate_rate(clk);
 503
 504out_unlock:
 505        spin_unlock_irqrestore(&clock_lock, flags);
 506
 507        return ret;
 508}
 509EXPORT_SYMBOL_GPL(clk_set_rate);
 510
 511int clk_set_parent(struct clk *clk, struct clk *parent)
 512{
 513        unsigned long flags;
 514        int ret = -EINVAL;
 515
 516        if (!parent || !clk)
 517                return ret;
 518        if (clk->parent == parent)
 519                return 0;
 520
 521        spin_lock_irqsave(&clock_lock, flags);
 522        if (clk->usecount == 0) {
 523                if (clk->ops->set_parent)
 524                        ret = clk->ops->set_parent(clk, parent);
 525                else
 526                        ret = clk_reparent(clk, parent);
 527
 528                if (ret == 0) {
 529                        if (clk->ops->recalc)
 530                                clk->rate = clk->ops->recalc(clk);
 531                        pr_debug("set parent of %p to %p (new rate %ld)\n",
 532                                 clk, clk->parent, clk->rate);
 533                        propagate_rate(clk);
 534                }
 535        } else
 536                ret = -EBUSY;
 537        spin_unlock_irqrestore(&clock_lock, flags);
 538
 539        return ret;
 540}
 541EXPORT_SYMBOL_GPL(clk_set_parent);
 542
 543struct clk *clk_get_parent(struct clk *clk)
 544{
 545        if (!clk)
 546                return NULL;
 547
 548        return clk->parent;
 549}
 550EXPORT_SYMBOL_GPL(clk_get_parent);
 551
 552long clk_round_rate(struct clk *clk, unsigned long rate)
 553{
 554        if (!clk)
 555                return 0;
 556
 557        if (likely(clk->ops && clk->ops->round_rate)) {
 558                unsigned long flags, rounded;
 559
 560                spin_lock_irqsave(&clock_lock, flags);
 561                rounded = clk->ops->round_rate(clk, rate);
 562                spin_unlock_irqrestore(&clock_lock, flags);
 563
 564                return rounded;
 565        }
 566
 567        return clk_get_rate(clk);
 568}
 569EXPORT_SYMBOL_GPL(clk_round_rate);
 570
 571#ifdef CONFIG_PM
 572static void clks_core_resume(void)
 573{
 574        struct clk *clkp;
 575
 576        list_for_each_entry(clkp, &clock_list, node) {
 577                if (likely(clkp->usecount && clkp->ops)) {
 578                        unsigned long rate = clkp->rate;
 579
 580                        if (likely(clkp->ops->set_parent))
 581                                clkp->ops->set_parent(clkp,
 582                                        clkp->parent);
 583                        if (likely(clkp->ops->set_rate))
 584                                clkp->ops->set_rate(clkp, rate);
 585                        else if (likely(clkp->ops->recalc))
 586                                clkp->rate = clkp->ops->recalc(clkp);
 587                }
 588        }
 589}
 590
 591static struct syscore_ops clks_syscore_ops = {
 592        .resume = clks_core_resume,
 593};
 594
 595static int __init clk_syscore_init(void)
 596{
 597        register_syscore_ops(&clks_syscore_ops);
 598
 599        return 0;
 600}
 601subsys_initcall(clk_syscore_init);
 602#endif
 603
 604static int __init clk_late_init(void)
 605{
 606        unsigned long flags;
 607        struct clk *clk;
 608
 609        /* disable all clocks with zero use count */
 610        mutex_lock(&clock_list_sem);
 611        spin_lock_irqsave(&clock_lock, flags);
 612
 613        list_for_each_entry(clk, &clock_list, node)
 614                if (!clk->usecount && clk->ops && clk->ops->disable)
 615                        clk->ops->disable(clk);
 616
 617        /* from now on allow clock disable operations */
 618        allow_disable = 1;
 619
 620        spin_unlock_irqrestore(&clock_lock, flags);
 621        mutex_unlock(&clock_list_sem);
 622        return 0;
 623}
 624late_initcall(clk_late_init);
 625