linux/drivers/clk/clk.c
<<
>>
Prefs
   1/*
   2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
   3 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License version 2 as
   7 * published by the Free Software Foundation.
   8 *
   9 * Standard functionality for the common clock API.  See Documentation/clk.txt
  10 */
  11
  12#include <linux/clk-private.h>
  13#include <linux/module.h>
  14#include <linux/mutex.h>
  15#include <linux/spinlock.h>
  16#include <linux/err.h>
  17#include <linux/list.h>
  18#include <linux/slab.h>
  19#include <linux/of.h>
  20#include <linux/device.h>
  21#include <linux/init.h>
  22#include <linux/sched.h>
  23
  24static DEFINE_SPINLOCK(enable_lock);
  25static DEFINE_MUTEX(prepare_lock);
  26
  27static struct task_struct *prepare_owner;
  28static struct task_struct *enable_owner;
  29
  30static int prepare_refcnt;
  31static int enable_refcnt;
  32
  33static HLIST_HEAD(clk_root_list);
  34static HLIST_HEAD(clk_orphan_list);
  35static LIST_HEAD(clk_notifier_list);
  36
  37/***           locking             ***/
  38static void clk_prepare_lock(void)
  39{
  40        if (!mutex_trylock(&prepare_lock)) {
  41                if (prepare_owner == current) {
  42                        prepare_refcnt++;
  43                        return;
  44                }
  45                mutex_lock(&prepare_lock);
  46        }
  47        WARN_ON_ONCE(prepare_owner != NULL);
  48        WARN_ON_ONCE(prepare_refcnt != 0);
  49        prepare_owner = current;
  50        prepare_refcnt = 1;
  51}
  52
  53static void clk_prepare_unlock(void)
  54{
  55        WARN_ON_ONCE(prepare_owner != current);
  56        WARN_ON_ONCE(prepare_refcnt == 0);
  57
  58        if (--prepare_refcnt)
  59                return;
  60        prepare_owner = NULL;
  61        mutex_unlock(&prepare_lock);
  62}
  63
  64static unsigned long clk_enable_lock(void)
  65{
  66        unsigned long flags;
  67
  68        if (!spin_trylock_irqsave(&enable_lock, flags)) {
  69                if (enable_owner == current) {
  70                        enable_refcnt++;
  71                        return flags;
  72                }
  73                spin_lock_irqsave(&enable_lock, flags);
  74        }
  75        WARN_ON_ONCE(enable_owner != NULL);
  76        WARN_ON_ONCE(enable_refcnt != 0);
  77        enable_owner = current;
  78        enable_refcnt = 1;
  79        return flags;
  80}
  81
  82static void clk_enable_unlock(unsigned long flags)
  83{
  84        WARN_ON_ONCE(enable_owner != current);
  85        WARN_ON_ONCE(enable_refcnt == 0);
  86
  87        if (--enable_refcnt)
  88                return;
  89        enable_owner = NULL;
  90        spin_unlock_irqrestore(&enable_lock, flags);
  91}
  92
  93/***        debugfs support        ***/
  94
  95#ifdef CONFIG_COMMON_CLK_DEBUG
  96#include <linux/debugfs.h>
  97
  98static struct dentry *rootdir;
  99static struct dentry *orphandir;
 100static int inited = 0;
 101
 102static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level)
 103{
 104        if (!c)
 105                return;
 106
 107        seq_printf(s, "%*s%-*s %-11d %-12d %-10lu",
 108                   level * 3 + 1, "",
 109                   30 - level * 3, c->name,
 110                   c->enable_count, c->prepare_count, clk_get_rate(c));
 111        seq_printf(s, "\n");
 112}
 113
 114static void clk_summary_show_subtree(struct seq_file *s, struct clk *c,
 115                                     int level)
 116{
 117        struct clk *child;
 118
 119        if (!c)
 120                return;
 121
 122        clk_summary_show_one(s, c, level);
 123
 124        hlist_for_each_entry(child, &c->children, child_node)
 125                clk_summary_show_subtree(s, child, level + 1);
 126}
 127
 128static int clk_summary_show(struct seq_file *s, void *data)
 129{
 130        struct clk *c;
 131
 132        seq_printf(s, "   clock                        enable_cnt  prepare_cnt  rate\n");
 133        seq_printf(s, "---------------------------------------------------------------------\n");
 134
 135        clk_prepare_lock();
 136
 137        hlist_for_each_entry(c, &clk_root_list, child_node)
 138                clk_summary_show_subtree(s, c, 0);
 139
 140        hlist_for_each_entry(c, &clk_orphan_list, child_node)
 141                clk_summary_show_subtree(s, c, 0);
 142
 143        clk_prepare_unlock();
 144
 145        return 0;
 146}
 147
 148
 149static int clk_summary_open(struct inode *inode, struct file *file)
 150{
 151        return single_open(file, clk_summary_show, inode->i_private);
 152}
 153
 154static const struct file_operations clk_summary_fops = {
 155        .open           = clk_summary_open,
 156        .read           = seq_read,
 157        .llseek         = seq_lseek,
 158        .release        = single_release,
 159};
 160
 161static void clk_dump_one(struct seq_file *s, struct clk *c, int level)
 162{
 163        if (!c)
 164                return;
 165
 166        seq_printf(s, "\"%s\": { ", c->name);
 167        seq_printf(s, "\"enable_count\": %d,", c->enable_count);
 168        seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
 169        seq_printf(s, "\"rate\": %lu", clk_get_rate(c));
 170}
 171
 172static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level)
 173{
 174        struct clk *child;
 175
 176        if (!c)
 177                return;
 178
 179        clk_dump_one(s, c, level);
 180
 181        hlist_for_each_entry(child, &c->children, child_node) {
 182                seq_printf(s, ",");
 183                clk_dump_subtree(s, child, level + 1);
 184        }
 185
 186        seq_printf(s, "}");
 187}
 188
 189static int clk_dump(struct seq_file *s, void *data)
 190{
 191        struct clk *c;
 192        bool first_node = true;
 193
 194        seq_printf(s, "{");
 195
 196        clk_prepare_lock();
 197
 198        hlist_for_each_entry(c, &clk_root_list, child_node) {
 199                if (!first_node)
 200                        seq_printf(s, ",");
 201                first_node = false;
 202                clk_dump_subtree(s, c, 0);
 203        }
 204
 205        hlist_for_each_entry(c, &clk_orphan_list, child_node) {
 206                seq_printf(s, ",");
 207                clk_dump_subtree(s, c, 0);
 208        }
 209
 210        clk_prepare_unlock();
 211
 212        seq_printf(s, "}");
 213        return 0;
 214}
 215
 216
 217static int clk_dump_open(struct inode *inode, struct file *file)
 218{
 219        return single_open(file, clk_dump, inode->i_private);
 220}
 221
 222static const struct file_operations clk_dump_fops = {
 223        .open           = clk_dump_open,
 224        .read           = seq_read,
 225        .llseek         = seq_lseek,
 226        .release        = single_release,
 227};
 228
 229/* caller must hold prepare_lock */
 230static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
 231{
 232        struct dentry *d;
 233        int ret = -ENOMEM;
 234
 235        if (!clk || !pdentry) {
 236                ret = -EINVAL;
 237                goto out;
 238        }
 239
 240        d = debugfs_create_dir(clk->name, pdentry);
 241        if (!d)
 242                goto out;
 243
 244        clk->dentry = d;
 245
 246        d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
 247                        (u32 *)&clk->rate);
 248        if (!d)
 249                goto err_out;
 250
 251        d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
 252                        (u32 *)&clk->flags);
 253        if (!d)
 254                goto err_out;
 255
 256        d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
 257                        (u32 *)&clk->prepare_count);
 258        if (!d)
 259                goto err_out;
 260
 261        d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
 262                        (u32 *)&clk->enable_count);
 263        if (!d)
 264                goto err_out;
 265
 266        d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
 267                        (u32 *)&clk->notifier_count);
 268        if (!d)
 269                goto err_out;
 270
 271        ret = 0;
 272        goto out;
 273
 274err_out:
 275        debugfs_remove(clk->dentry);
 276out:
 277        return ret;
 278}
 279
 280/* caller must hold prepare_lock */
 281static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry)
 282{
 283        struct clk *child;
 284        int ret = -EINVAL;;
 285
 286        if (!clk || !pdentry)
 287                goto out;
 288
 289        ret = clk_debug_create_one(clk, pdentry);
 290
 291        if (ret)
 292                goto out;
 293
 294        hlist_for_each_entry(child, &clk->children, child_node)
 295                clk_debug_create_subtree(child, clk->dentry);
 296
 297        ret = 0;
 298out:
 299        return ret;
 300}
 301
 302/**
 303 * clk_debug_register - add a clk node to the debugfs clk tree
 304 * @clk: the clk being added to the debugfs clk tree
 305 *
 306 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
 307 * initialized.  Otherwise it bails out early since the debugfs clk tree
 308 * will be created lazily by clk_debug_init as part of a late_initcall.
 309 *
 310 * Caller must hold prepare_lock.  Only clk_init calls this function (so
 311 * far) so this is taken care.
 312 */
 313static int clk_debug_register(struct clk *clk)
 314{
 315        struct clk *parent;
 316        struct dentry *pdentry;
 317        int ret = 0;
 318
 319        if (!inited)
 320                goto out;
 321
 322        parent = clk->parent;
 323
 324        /*
 325         * Check to see if a clk is a root clk.  Also check that it is
 326         * safe to add this clk to debugfs
 327         */
 328        if (!parent)
 329                if (clk->flags & CLK_IS_ROOT)
 330                        pdentry = rootdir;
 331                else
 332                        pdentry = orphandir;
 333        else
 334                if (parent->dentry)
 335                        pdentry = parent->dentry;
 336                else
 337                        goto out;
 338
 339        ret = clk_debug_create_subtree(clk, pdentry);
 340
 341out:
 342        return ret;
 343}
 344
 345/**
 346 * clk_debug_reparent - reparent clk node in the debugfs clk tree
 347 * @clk: the clk being reparented
 348 * @new_parent: the new clk parent, may be NULL
 349 *
 350 * Rename clk entry in the debugfs clk tree if debugfs has been
 351 * initialized.  Otherwise it bails out early since the debugfs clk tree
 352 * will be created lazily by clk_debug_init as part of a late_initcall.
 353 *
 354 * Caller must hold prepare_lock.
 355 */
 356static void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
 357{
 358        struct dentry *d;
 359        struct dentry *new_parent_d;
 360
 361        if (!inited)
 362                return;
 363
 364        if (new_parent)
 365                new_parent_d = new_parent->dentry;
 366        else
 367                new_parent_d = orphandir;
 368
 369        d = debugfs_rename(clk->dentry->d_parent, clk->dentry,
 370                        new_parent_d, clk->name);
 371        if (d)
 372                clk->dentry = d;
 373        else
 374                pr_debug("%s: failed to rename debugfs entry for %s\n",
 375                                __func__, clk->name);
 376}
 377
 378/**
 379 * clk_debug_init - lazily create the debugfs clk tree visualization
 380 *
 381 * clks are often initialized very early during boot before memory can
 382 * be dynamically allocated and well before debugfs is setup.
 383 * clk_debug_init walks the clk tree hierarchy while holding
 384 * prepare_lock and creates the topology as part of a late_initcall,
 385 * thus insuring that clks initialized very early will still be
 386 * represented in the debugfs clk tree.  This function should only be
 387 * called once at boot-time, and all other clks added dynamically will
 388 * be done so with clk_debug_register.
 389 */
 390static int __init clk_debug_init(void)
 391{
 392        struct clk *clk;
 393        struct dentry *d;
 394
 395        rootdir = debugfs_create_dir("clk", NULL);
 396
 397        if (!rootdir)
 398                return -ENOMEM;
 399
 400        d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, NULL,
 401                                &clk_summary_fops);
 402        if (!d)
 403                return -ENOMEM;
 404
 405        d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, NULL,
 406                                &clk_dump_fops);
 407        if (!d)
 408                return -ENOMEM;
 409
 410        orphandir = debugfs_create_dir("orphans", rootdir);
 411
 412        if (!orphandir)
 413                return -ENOMEM;
 414
 415        clk_prepare_lock();
 416
 417        hlist_for_each_entry(clk, &clk_root_list, child_node)
 418                clk_debug_create_subtree(clk, rootdir);
 419
 420        hlist_for_each_entry(clk, &clk_orphan_list, child_node)
 421                clk_debug_create_subtree(clk, orphandir);
 422
 423        inited = 1;
 424
 425        clk_prepare_unlock();
 426
 427        return 0;
 428}
 429late_initcall(clk_debug_init);
 430#else
 431static inline int clk_debug_register(struct clk *clk) { return 0; }
 432static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
 433{
 434}
 435#endif
 436
 437/* caller must hold prepare_lock */
 438static void clk_unprepare_unused_subtree(struct clk *clk)
 439{
 440        struct clk *child;
 441
 442        if (!clk)
 443                return;
 444
 445        hlist_for_each_entry(child, &clk->children, child_node)
 446                clk_unprepare_unused_subtree(child);
 447
 448        if (clk->prepare_count)
 449                return;
 450
 451        if (clk->flags & CLK_IGNORE_UNUSED)
 452                return;
 453
 454        if (__clk_is_prepared(clk)) {
 455                if (clk->ops->unprepare_unused)
 456                        clk->ops->unprepare_unused(clk->hw);
 457                else if (clk->ops->unprepare)
 458                        clk->ops->unprepare(clk->hw);
 459        }
 460}
 461EXPORT_SYMBOL_GPL(__clk_get_flags);
 462
 463/* caller must hold prepare_lock */
 464static void clk_disable_unused_subtree(struct clk *clk)
 465{
 466        struct clk *child;
 467        unsigned long flags;
 468
 469        if (!clk)
 470                goto out;
 471
 472        hlist_for_each_entry(child, &clk->children, child_node)
 473                clk_disable_unused_subtree(child);
 474
 475        flags = clk_enable_lock();
 476
 477        if (clk->enable_count)
 478                goto unlock_out;
 479
 480        if (clk->flags & CLK_IGNORE_UNUSED)
 481                goto unlock_out;
 482
 483        /*
 484         * some gate clocks have special needs during the disable-unused
 485         * sequence.  call .disable_unused if available, otherwise fall
 486         * back to .disable
 487         */
 488        if (__clk_is_enabled(clk)) {
 489                if (clk->ops->disable_unused)
 490                        clk->ops->disable_unused(clk->hw);
 491                else if (clk->ops->disable)
 492                        clk->ops->disable(clk->hw);
 493        }
 494
 495unlock_out:
 496        clk_enable_unlock(flags);
 497
 498out:
 499        return;
 500}
 501
 502static bool clk_ignore_unused;
 503static int __init clk_ignore_unused_setup(char *__unused)
 504{
 505        clk_ignore_unused = true;
 506        return 1;
 507}
 508__setup("clk_ignore_unused", clk_ignore_unused_setup);
 509
 510static int clk_disable_unused(void)
 511{
 512        struct clk *clk;
 513
 514        if (clk_ignore_unused) {
 515                pr_warn("clk: Not disabling unused clocks\n");
 516                return 0;
 517        }
 518
 519        clk_prepare_lock();
 520
 521        hlist_for_each_entry(clk, &clk_root_list, child_node)
 522                clk_disable_unused_subtree(clk);
 523
 524        hlist_for_each_entry(clk, &clk_orphan_list, child_node)
 525                clk_disable_unused_subtree(clk);
 526
 527        hlist_for_each_entry(clk, &clk_root_list, child_node)
 528                clk_unprepare_unused_subtree(clk);
 529
 530        hlist_for_each_entry(clk, &clk_orphan_list, child_node)
 531                clk_unprepare_unused_subtree(clk);
 532
 533        clk_prepare_unlock();
 534
 535        return 0;
 536}
 537late_initcall_sync(clk_disable_unused);
 538
 539/***    helper functions   ***/
 540
 541const char *__clk_get_name(struct clk *clk)
 542{
 543        return !clk ? NULL : clk->name;
 544}
 545EXPORT_SYMBOL_GPL(__clk_get_name);
 546
 547struct clk_hw *__clk_get_hw(struct clk *clk)
 548{
 549        return !clk ? NULL : clk->hw;
 550}
 551
 552u8 __clk_get_num_parents(struct clk *clk)
 553{
 554        return !clk ? 0 : clk->num_parents;
 555}
 556
 557struct clk *__clk_get_parent(struct clk *clk)
 558{
 559        return !clk ? NULL : clk->parent;
 560}
 561
 562unsigned int __clk_get_enable_count(struct clk *clk)
 563{
 564        return !clk ? 0 : clk->enable_count;
 565}
 566
 567unsigned int __clk_get_prepare_count(struct clk *clk)
 568{
 569        return !clk ? 0 : clk->prepare_count;
 570}
 571
 572unsigned long __clk_get_rate(struct clk *clk)
 573{
 574        unsigned long ret;
 575
 576        if (!clk) {
 577                ret = 0;
 578                goto out;
 579        }
 580
 581        ret = clk->rate;
 582
 583        if (clk->flags & CLK_IS_ROOT)
 584                goto out;
 585
 586        if (!clk->parent)
 587                ret = 0;
 588
 589out:
 590        return ret;
 591}
 592
 593unsigned long __clk_get_flags(struct clk *clk)
 594{
 595        return !clk ? 0 : clk->flags;
 596}
 597
 598bool __clk_is_prepared(struct clk *clk)
 599{
 600        int ret;
 601
 602        if (!clk)
 603                return false;
 604
 605        /*
 606         * .is_prepared is optional for clocks that can prepare
 607         * fall back to software usage counter if it is missing
 608         */
 609        if (!clk->ops->is_prepared) {
 610                ret = clk->prepare_count ? 1 : 0;
 611                goto out;
 612        }
 613
 614        ret = clk->ops->is_prepared(clk->hw);
 615out:
 616        return !!ret;
 617}
 618
 619bool __clk_is_enabled(struct clk *clk)
 620{
 621        int ret;
 622
 623        if (!clk)
 624                return false;
 625
 626        /*
 627         * .is_enabled is only mandatory for clocks that gate
 628         * fall back to software usage counter if .is_enabled is missing
 629         */
 630        if (!clk->ops->is_enabled) {
 631                ret = clk->enable_count ? 1 : 0;
 632                goto out;
 633        }
 634
 635        ret = clk->ops->is_enabled(clk->hw);
 636out:
 637        return !!ret;
 638}
 639
 640static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
 641{
 642        struct clk *child;
 643        struct clk *ret;
 644
 645        if (!strcmp(clk->name, name))
 646                return clk;
 647
 648        hlist_for_each_entry(child, &clk->children, child_node) {
 649                ret = __clk_lookup_subtree(name, child);
 650                if (ret)
 651                        return ret;
 652        }
 653
 654        return NULL;
 655}
 656
 657struct clk *__clk_lookup(const char *name)
 658{
 659        struct clk *root_clk;
 660        struct clk *ret;
 661
 662        if (!name)
 663                return NULL;
 664
 665        /* search the 'proper' clk tree first */
 666        hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
 667                ret = __clk_lookup_subtree(name, root_clk);
 668                if (ret)
 669                        return ret;
 670        }
 671
 672        /* if not found, then search the orphan tree */
 673        hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
 674                ret = __clk_lookup_subtree(name, root_clk);
 675                if (ret)
 676                        return ret;
 677        }
 678
 679        return NULL;
 680}
 681
 682/***        clk api        ***/
 683
 684void __clk_unprepare(struct clk *clk)
 685{
 686        if (!clk)
 687                return;
 688
 689        if (WARN_ON(clk->prepare_count == 0))
 690                return;
 691
 692        if (--clk->prepare_count > 0)
 693                return;
 694
 695        WARN_ON(clk->enable_count > 0);
 696
 697        if (clk->ops->unprepare)
 698                clk->ops->unprepare(clk->hw);
 699
 700        __clk_unprepare(clk->parent);
 701}
 702
 703/**
 704 * clk_unprepare - undo preparation of a clock source
 705 * @clk: the clk being unprepare
 706 *
 707 * clk_unprepare may sleep, which differentiates it from clk_disable.  In a
 708 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
 709 * if the operation may sleep.  One example is a clk which is accessed over
 710 * I2c.  In the complex case a clk gate operation may require a fast and a slow
 711 * part.  It is this reason that clk_unprepare and clk_disable are not mutually
 712 * exclusive.  In fact clk_disable must be called before clk_unprepare.
 713 */
 714void clk_unprepare(struct clk *clk)
 715{
 716        clk_prepare_lock();
 717        __clk_unprepare(clk);
 718        clk_prepare_unlock();
 719}
 720EXPORT_SYMBOL_GPL(clk_unprepare);
 721
 722int __clk_prepare(struct clk *clk)
 723{
 724        int ret = 0;
 725
 726        if (!clk)
 727                return 0;
 728
 729        if (clk->prepare_count == 0) {
 730                ret = __clk_prepare(clk->parent);
 731                if (ret)
 732                        return ret;
 733
 734                if (clk->ops->prepare) {
 735                        ret = clk->ops->prepare(clk->hw);
 736                        if (ret) {
 737                                __clk_unprepare(clk->parent);
 738                                return ret;
 739                        }
 740                }
 741        }
 742
 743        clk->prepare_count++;
 744
 745        return 0;
 746}
 747
 748/**
 749 * clk_prepare - prepare a clock source
 750 * @clk: the clk being prepared
 751 *
 752 * clk_prepare may sleep, which differentiates it from clk_enable.  In a simple
 753 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
 754 * operation may sleep.  One example is a clk which is accessed over I2c.  In
 755 * the complex case a clk ungate operation may require a fast and a slow part.
 756 * It is this reason that clk_prepare and clk_enable are not mutually
 757 * exclusive.  In fact clk_prepare must be called before clk_enable.
 758 * Returns 0 on success, -EERROR otherwise.
 759 */
 760int clk_prepare(struct clk *clk)
 761{
 762        int ret;
 763
 764        clk_prepare_lock();
 765        ret = __clk_prepare(clk);
 766        clk_prepare_unlock();
 767
 768        return ret;
 769}
 770EXPORT_SYMBOL_GPL(clk_prepare);
 771
 772static void __clk_disable(struct clk *clk)
 773{
 774        if (!clk)
 775                return;
 776
 777        if (WARN_ON(IS_ERR(clk)))
 778                return;
 779
 780        if (WARN_ON(clk->enable_count == 0))
 781                return;
 782
 783        if (--clk->enable_count > 0)
 784                return;
 785
 786        if (clk->ops->disable)
 787                clk->ops->disable(clk->hw);
 788
 789        __clk_disable(clk->parent);
 790}
 791
 792/**
 793 * clk_disable - gate a clock
 794 * @clk: the clk being gated
 795 *
 796 * clk_disable must not sleep, which differentiates it from clk_unprepare.  In
 797 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
 798 * clk if the operation is fast and will never sleep.  One example is a
 799 * SoC-internal clk which is controlled via simple register writes.  In the
 800 * complex case a clk gate operation may require a fast and a slow part.  It is
 801 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
 802 * In fact clk_disable must be called before clk_unprepare.
 803 */
 804void clk_disable(struct clk *clk)
 805{
 806        unsigned long flags;
 807
 808        flags = clk_enable_lock();
 809        __clk_disable(clk);
 810        clk_enable_unlock(flags);
 811}
 812EXPORT_SYMBOL_GPL(clk_disable);
 813
 814static int __clk_enable(struct clk *clk)
 815{
 816        int ret = 0;
 817
 818        if (!clk)
 819                return 0;
 820
 821        if (WARN_ON(clk->prepare_count == 0))
 822                return -ESHUTDOWN;
 823
 824        if (clk->enable_count == 0) {
 825                ret = __clk_enable(clk->parent);
 826
 827                if (ret)
 828                        return ret;
 829
 830                if (clk->ops->enable) {
 831                        ret = clk->ops->enable(clk->hw);
 832                        if (ret) {
 833                                __clk_disable(clk->parent);
 834                                return ret;
 835                        }
 836                }
 837        }
 838
 839        clk->enable_count++;
 840        return 0;
 841}
 842
 843/**
 844 * clk_enable - ungate a clock
 845 * @clk: the clk being ungated
 846 *
 847 * clk_enable must not sleep, which differentiates it from clk_prepare.  In a
 848 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
 849 * if the operation will never sleep.  One example is a SoC-internal clk which
 850 * is controlled via simple register writes.  In the complex case a clk ungate
 851 * operation may require a fast and a slow part.  It is this reason that
 852 * clk_enable and clk_prepare are not mutually exclusive.  In fact clk_prepare
 853 * must be called before clk_enable.  Returns 0 on success, -EERROR
 854 * otherwise.
 855 */
 856int clk_enable(struct clk *clk)
 857{
 858        unsigned long flags;
 859        int ret;
 860
 861        flags = clk_enable_lock();
 862        ret = __clk_enable(clk);
 863        clk_enable_unlock(flags);
 864
 865        return ret;
 866}
 867EXPORT_SYMBOL_GPL(clk_enable);
 868
 869/**
 870 * __clk_round_rate - round the given rate for a clk
 871 * @clk: round the rate of this clock
 872 *
 873 * Caller must hold prepare_lock.  Useful for clk_ops such as .set_rate
 874 */
 875unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
 876{
 877        unsigned long parent_rate = 0;
 878
 879        if (!clk)
 880                return 0;
 881
 882        if (!clk->ops->round_rate) {
 883                if (clk->flags & CLK_SET_RATE_PARENT)
 884                        return __clk_round_rate(clk->parent, rate);
 885                else
 886                        return clk->rate;
 887        }
 888
 889        if (clk->parent)
 890                parent_rate = clk->parent->rate;
 891
 892        return clk->ops->round_rate(clk->hw, rate, &parent_rate);
 893}
 894
 895/**
 896 * clk_round_rate - round the given rate for a clk
 897 * @clk: the clk for which we are rounding a rate
 898 * @rate: the rate which is to be rounded
 899 *
 900 * Takes in a rate as input and rounds it to a rate that the clk can actually
 901 * use which is then returned.  If clk doesn't support round_rate operation
 902 * then the parent rate is returned.
 903 */
 904long clk_round_rate(struct clk *clk, unsigned long rate)
 905{
 906        unsigned long ret;
 907
 908        clk_prepare_lock();
 909        ret = __clk_round_rate(clk, rate);
 910        clk_prepare_unlock();
 911
 912        return ret;
 913}
 914EXPORT_SYMBOL_GPL(clk_round_rate);
 915
 916/**
 917 * __clk_notify - call clk notifier chain
 918 * @clk: struct clk * that is changing rate
 919 * @msg: clk notifier type (see include/linux/clk.h)
 920 * @old_rate: old clk rate
 921 * @new_rate: new clk rate
 922 *
 923 * Triggers a notifier call chain on the clk rate-change notification
 924 * for 'clk'.  Passes a pointer to the struct clk and the previous
 925 * and current rates to the notifier callback.  Intended to be called by
 926 * internal clock code only.  Returns NOTIFY_DONE from the last driver
 927 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
 928 * a driver returns that.
 929 */
 930static int __clk_notify(struct clk *clk, unsigned long msg,
 931                unsigned long old_rate, unsigned long new_rate)
 932{
 933        struct clk_notifier *cn;
 934        struct clk_notifier_data cnd;
 935        int ret = NOTIFY_DONE;
 936
 937        cnd.clk = clk;
 938        cnd.old_rate = old_rate;
 939        cnd.new_rate = new_rate;
 940
 941        list_for_each_entry(cn, &clk_notifier_list, node) {
 942                if (cn->clk == clk) {
 943                        ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
 944                                        &cnd);
 945                        break;
 946                }
 947        }
 948
 949        return ret;
 950}
 951
 952/**
 953 * __clk_recalc_rates
 954 * @clk: first clk in the subtree
 955 * @msg: notification type (see include/linux/clk.h)
 956 *
 957 * Walks the subtree of clks starting with clk and recalculates rates as it
 958 * goes.  Note that if a clk does not implement the .recalc_rate callback then
 959 * it is assumed that the clock will take on the rate of it's parent.
 960 *
 961 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
 962 * if necessary.
 963 *
 964 * Caller must hold prepare_lock.
 965 */
 966static void __clk_recalc_rates(struct clk *clk, unsigned long msg)
 967{
 968        unsigned long old_rate;
 969        unsigned long parent_rate = 0;
 970        struct clk *child;
 971
 972        old_rate = clk->rate;
 973
 974        if (clk->parent)
 975                parent_rate = clk->parent->rate;
 976
 977        if (clk->ops->recalc_rate)
 978                clk->rate = clk->ops->recalc_rate(clk->hw, parent_rate);
 979        else
 980                clk->rate = parent_rate;
 981
 982        /*
 983         * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
 984         * & ABORT_RATE_CHANGE notifiers
 985         */
 986        if (clk->notifier_count && msg)
 987                __clk_notify(clk, msg, old_rate, clk->rate);
 988
 989        hlist_for_each_entry(child, &clk->children, child_node)
 990                __clk_recalc_rates(child, msg);
 991}
 992
 993/**
 994 * clk_get_rate - return the rate of clk
 995 * @clk: the clk whose rate is being returned
 996 *
 997 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
 998 * is set, which means a recalc_rate will be issued.
 999 * If clk is NULL then returns 0.
1000 */
1001unsigned long clk_get_rate(struct clk *clk)
1002{
1003        unsigned long rate;
1004
1005        clk_prepare_lock();
1006
1007        if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
1008                __clk_recalc_rates(clk, 0);
1009
1010        rate = __clk_get_rate(clk);
1011        clk_prepare_unlock();
1012
1013        return rate;
1014}
1015EXPORT_SYMBOL_GPL(clk_get_rate);
1016
1017/**
1018 * __clk_speculate_rates
1019 * @clk: first clk in the subtree
1020 * @parent_rate: the "future" rate of clk's parent
1021 *
1022 * Walks the subtree of clks starting with clk, speculating rates as it
1023 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
1024 *
1025 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
1026 * pre-rate change notifications and returns early if no clks in the
1027 * subtree have subscribed to the notifications.  Note that if a clk does not
1028 * implement the .recalc_rate callback then it is assumed that the clock will
1029 * take on the rate of it's parent.
1030 *
1031 * Caller must hold prepare_lock.
1032 */
1033static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate)
1034{
1035        struct clk *child;
1036        unsigned long new_rate;
1037        int ret = NOTIFY_DONE;
1038
1039        if (clk->ops->recalc_rate)
1040                new_rate = clk->ops->recalc_rate(clk->hw, parent_rate);
1041        else
1042                new_rate = parent_rate;
1043
1044        /* abort rate change if a driver returns NOTIFY_BAD or NOTIFY_STOP */
1045        if (clk->notifier_count)
1046                ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
1047
1048        if (ret & NOTIFY_STOP_MASK)
1049                goto out;
1050
1051        hlist_for_each_entry(child, &clk->children, child_node) {
1052                ret = __clk_speculate_rates(child, new_rate);
1053                if (ret & NOTIFY_STOP_MASK)
1054                        break;
1055        }
1056
1057out:
1058        return ret;
1059}
1060
1061static void clk_calc_subtree(struct clk *clk, unsigned long new_rate)
1062{
1063        struct clk *child;
1064
1065        clk->new_rate = new_rate;
1066
1067        hlist_for_each_entry(child, &clk->children, child_node) {
1068                if (child->ops->recalc_rate)
1069                        child->new_rate = child->ops->recalc_rate(child->hw, new_rate);
1070                else
1071                        child->new_rate = new_rate;
1072                clk_calc_subtree(child, child->new_rate);
1073        }
1074}
1075
1076/*
1077 * calculate the new rates returning the topmost clock that has to be
1078 * changed.
1079 */
1080static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
1081{
1082        struct clk *top = clk;
1083        unsigned long best_parent_rate = 0;
1084        unsigned long new_rate;
1085
1086        /* sanity */
1087        if (IS_ERR_OR_NULL(clk))
1088                return NULL;
1089
1090        /* save parent rate, if it exists */
1091        if (clk->parent)
1092                best_parent_rate = clk->parent->rate;
1093
1094        /* never propagate up to the parent */
1095        if (!(clk->flags & CLK_SET_RATE_PARENT)) {
1096                if (!clk->ops->round_rate) {
1097                        clk->new_rate = clk->rate;
1098                        return NULL;
1099                }
1100                new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
1101                goto out;
1102        }
1103
1104        /* need clk->parent from here on out */
1105        if (!clk->parent) {
1106                pr_debug("%s: %s has NULL parent\n", __func__, clk->name);
1107                return NULL;
1108        }
1109
1110        if (!clk->ops->round_rate) {
1111                top = clk_calc_new_rates(clk->parent, rate);
1112                new_rate = clk->parent->new_rate;
1113
1114                goto out;
1115        }
1116
1117        new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
1118
1119        if (best_parent_rate != clk->parent->rate) {
1120                top = clk_calc_new_rates(clk->parent, best_parent_rate);
1121
1122                goto out;
1123        }
1124
1125out:
1126        clk_calc_subtree(clk, new_rate);
1127
1128        return top;
1129}
1130
1131/*
1132 * Notify about rate changes in a subtree. Always walk down the whole tree
1133 * so that in case of an error we can walk down the whole tree again and
1134 * abort the change.
1135 */
1136static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event)
1137{
1138        struct clk *child, *fail_clk = NULL;
1139        int ret = NOTIFY_DONE;
1140
1141        if (clk->rate == clk->new_rate)
1142                return NULL;
1143
1144        if (clk->notifier_count) {
1145                ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
1146                if (ret & NOTIFY_STOP_MASK)
1147                        fail_clk = clk;
1148        }
1149
1150        hlist_for_each_entry(child, &clk->children, child_node) {
1151                clk = clk_propagate_rate_change(child, event);
1152                if (clk)
1153                        fail_clk = clk;
1154        }
1155
1156        return fail_clk;
1157}
1158
1159/*
1160 * walk down a subtree and set the new rates notifying the rate
1161 * change on the way
1162 */
1163static void clk_change_rate(struct clk *clk)
1164{
1165        struct clk *child;
1166        unsigned long old_rate;
1167        unsigned long best_parent_rate = 0;
1168
1169        old_rate = clk->rate;
1170
1171        if (clk->parent)
1172                best_parent_rate = clk->parent->rate;
1173
1174        if (clk->ops->set_rate)
1175                clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
1176
1177        if (clk->ops->recalc_rate)
1178                clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate);
1179        else
1180                clk->rate = best_parent_rate;
1181
1182        if (clk->notifier_count && old_rate != clk->rate)
1183                __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
1184
1185        hlist_for_each_entry(child, &clk->children, child_node)
1186                clk_change_rate(child);
1187}
1188
1189/**
1190 * clk_set_rate - specify a new rate for clk
1191 * @clk: the clk whose rate is being changed
1192 * @rate: the new rate for clk
1193 *
1194 * In the simplest case clk_set_rate will only adjust the rate of clk.
1195 *
1196 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1197 * propagate up to clk's parent; whether or not this happens depends on the
1198 * outcome of clk's .round_rate implementation.  If *parent_rate is unchanged
1199 * after calling .round_rate then upstream parent propagation is ignored.  If
1200 * *parent_rate comes back with a new rate for clk's parent then we propagate
1201 * up to clk's parent and set it's rate.  Upward propagation will continue
1202 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1203 * .round_rate stops requesting changes to clk's parent_rate.
1204 *
1205 * Rate changes are accomplished via tree traversal that also recalculates the
1206 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1207 *
1208 * Returns 0 on success, -EERROR otherwise.
1209 */
1210int clk_set_rate(struct clk *clk, unsigned long rate)
1211{
1212        struct clk *top, *fail_clk;
1213        int ret = 0;
1214
1215        /* prevent racing with updates to the clock topology */
1216        clk_prepare_lock();
1217
1218        /* bail early if nothing to do */
1219        if (rate == clk_get_rate(clk))
1220                goto out;
1221
1222        if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
1223                ret = -EBUSY;
1224                goto out;
1225        }
1226
1227        /* calculate new rates and get the topmost changed clock */
1228        top = clk_calc_new_rates(clk, rate);
1229        if (!top) {
1230                ret = -EINVAL;
1231                goto out;
1232        }
1233
1234        /* notify that we are about to change rates */
1235        fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
1236        if (fail_clk) {
1237                pr_warn("%s: failed to set %s rate\n", __func__,
1238                                fail_clk->name);
1239                clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
1240                ret = -EBUSY;
1241                goto out;
1242        }
1243
1244        /* change the rates */
1245        clk_change_rate(top);
1246
1247out:
1248        clk_prepare_unlock();
1249
1250        return ret;
1251}
1252EXPORT_SYMBOL_GPL(clk_set_rate);
1253
1254/**
1255 * clk_get_parent - return the parent of a clk
1256 * @clk: the clk whose parent gets returned
1257 *
1258 * Simply returns clk->parent.  Returns NULL if clk is NULL.
1259 */
1260struct clk *clk_get_parent(struct clk *clk)
1261{
1262        struct clk *parent;
1263
1264        clk_prepare_lock();
1265        parent = __clk_get_parent(clk);
1266        clk_prepare_unlock();
1267
1268        return parent;
1269}
1270EXPORT_SYMBOL_GPL(clk_get_parent);
1271
1272/*
1273 * .get_parent is mandatory for clocks with multiple possible parents.  It is
1274 * optional for single-parent clocks.  Always call .get_parent if it is
1275 * available and WARN if it is missing for multi-parent clocks.
1276 *
1277 * For single-parent clocks without .get_parent, first check to see if the
1278 * .parents array exists, and if so use it to avoid an expensive tree
1279 * traversal.  If .parents does not exist then walk the tree with __clk_lookup.
1280 */
1281static struct clk *__clk_init_parent(struct clk *clk)
1282{
1283        struct clk *ret = NULL;
1284        u8 index;
1285
1286        /* handle the trivial cases */
1287
1288        if (!clk->num_parents)
1289                goto out;
1290
1291        if (clk->num_parents == 1) {
1292                if (IS_ERR_OR_NULL(clk->parent))
1293                        ret = clk->parent = __clk_lookup(clk->parent_names[0]);
1294                ret = clk->parent;
1295                goto out;
1296        }
1297
1298        if (!clk->ops->get_parent) {
1299                WARN(!clk->ops->get_parent,
1300                        "%s: multi-parent clocks must implement .get_parent\n",
1301                        __func__);
1302                goto out;
1303        };
1304
1305        /*
1306         * Do our best to cache parent clocks in clk->parents.  This prevents
1307         * unnecessary and expensive calls to __clk_lookup.  We don't set
1308         * clk->parent here; that is done by the calling function
1309         */
1310
1311        index = clk->ops->get_parent(clk->hw);
1312
1313        if (!clk->parents)
1314                clk->parents =
1315                        kzalloc((sizeof(struct clk*) * clk->num_parents),
1316                                        GFP_KERNEL);
1317
1318        if (!clk->parents)
1319                ret = __clk_lookup(clk->parent_names[index]);
1320        else if (!clk->parents[index])
1321                ret = clk->parents[index] =
1322                        __clk_lookup(clk->parent_names[index]);
1323        else
1324                ret = clk->parents[index];
1325
1326out:
1327        return ret;
1328}
1329
1330static void clk_reparent(struct clk *clk, struct clk *new_parent)
1331{
1332        hlist_del(&clk->child_node);
1333
1334        if (new_parent)
1335                hlist_add_head(&clk->child_node, &new_parent->children);
1336        else
1337                hlist_add_head(&clk->child_node, &clk_orphan_list);
1338
1339        clk->parent = new_parent;
1340}
1341
1342void __clk_reparent(struct clk *clk, struct clk *new_parent)
1343{
1344        clk_reparent(clk, new_parent);
1345        clk_debug_reparent(clk, new_parent);
1346        __clk_recalc_rates(clk, POST_RATE_CHANGE);
1347}
1348
1349static u8 clk_fetch_parent_index(struct clk *clk, struct clk *parent)
1350{
1351        u8 i;
1352
1353        if (!clk->parents)
1354                clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
1355                                                                GFP_KERNEL);
1356
1357        /*
1358         * find index of new parent clock using cached parent ptrs,
1359         * or if not yet cached, use string name comparison and cache
1360         * them now to avoid future calls to __clk_lookup.
1361         */
1362        for (i = 0; i < clk->num_parents; i++) {
1363                if (clk->parents && clk->parents[i] == parent)
1364                        break;
1365                else if (!strcmp(clk->parent_names[i], parent->name)) {
1366                        if (clk->parents)
1367                                clk->parents[i] = __clk_lookup(parent->name);
1368                        break;
1369                }
1370        }
1371
1372        return i;
1373}
1374
1375static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index)
1376{
1377        unsigned long flags;
1378        int ret = 0;
1379        struct clk *old_parent = clk->parent;
1380
1381        /*
1382         * Migrate prepare state between parents and prevent race with
1383         * clk_enable().
1384         *
1385         * If the clock is not prepared, then a race with
1386         * clk_enable/disable() is impossible since we already have the
1387         * prepare lock (future calls to clk_enable() need to be preceded by
1388         * a clk_prepare()).
1389         *
1390         * If the clock is prepared, migrate the prepared state to the new
1391         * parent and also protect against a race with clk_enable() by
1392         * forcing the clock and the new parent on.  This ensures that all
1393         * future calls to clk_enable() are practically NOPs with respect to
1394         * hardware and software states.
1395         *
1396         * See also: Comment for clk_set_parent() below.
1397         */
1398        if (clk->prepare_count) {
1399                __clk_prepare(parent);
1400                clk_enable(parent);
1401                clk_enable(clk);
1402        }
1403
1404        /* update the clk tree topology */
1405        flags = clk_enable_lock();
1406        clk_reparent(clk, parent);
1407        clk_enable_unlock(flags);
1408
1409        /* change clock input source */
1410        if (parent && clk->ops->set_parent)
1411                ret = clk->ops->set_parent(clk->hw, p_index);
1412
1413        if (ret) {
1414                flags = clk_enable_lock();
1415                clk_reparent(clk, old_parent);
1416                clk_enable_unlock(flags);
1417
1418                if (clk->prepare_count) {
1419                        clk_disable(clk);
1420                        clk_disable(parent);
1421                        __clk_unprepare(parent);
1422                }
1423                return ret;
1424        }
1425
1426        /*
1427         * Finish the migration of prepare state and undo the changes done
1428         * for preventing a race with clk_enable().
1429         */
1430        if (clk->prepare_count) {
1431                clk_disable(clk);
1432                clk_disable(old_parent);
1433                __clk_unprepare(old_parent);
1434        }
1435
1436        /* update debugfs with new clk tree topology */
1437        clk_debug_reparent(clk, parent);
1438        return 0;
1439}
1440
1441/**
1442 * clk_set_parent - switch the parent of a mux clk
1443 * @clk: the mux clk whose input we are switching
1444 * @parent: the new input to clk
1445 *
1446 * Re-parent clk to use parent as its new input source.  If clk is in
1447 * prepared state, the clk will get enabled for the duration of this call. If
1448 * that's not acceptable for a specific clk (Eg: the consumer can't handle
1449 * that, the reparenting is glitchy in hardware, etc), use the
1450 * CLK_SET_PARENT_GATE flag to allow reparenting only when clk is unprepared.
1451 *
1452 * After successfully changing clk's parent clk_set_parent will update the
1453 * clk topology, sysfs topology and propagate rate recalculation via
1454 * __clk_recalc_rates.
1455 *
1456 * Returns 0 on success, -EERROR otherwise.
1457 */
1458int clk_set_parent(struct clk *clk, struct clk *parent)
1459{
1460        int ret = 0;
1461        u8 p_index = 0;
1462        unsigned long p_rate = 0;
1463
1464        if (!clk || !clk->ops)
1465                return -EINVAL;
1466
1467        /* verify ops for for multi-parent clks */
1468        if ((clk->num_parents > 1) && (!clk->ops->set_parent))
1469                return -ENOSYS;
1470
1471        /* prevent racing with updates to the clock topology */
1472        clk_prepare_lock();
1473
1474        if (clk->parent == parent)
1475                goto out;
1476
1477        /* check that we are allowed to re-parent if the clock is in use */
1478        if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) {
1479                ret = -EBUSY;
1480                goto out;
1481        }
1482
1483        /* try finding the new parent index */
1484        if (parent) {
1485                p_index = clk_fetch_parent_index(clk, parent);
1486                p_rate = parent->rate;
1487                if (p_index == clk->num_parents) {
1488                        pr_debug("%s: clk %s can not be parent of clk %s\n",
1489                                        __func__, parent->name, clk->name);
1490                        ret = -EINVAL;
1491                        goto out;
1492                }
1493        }
1494
1495        /* propagate PRE_RATE_CHANGE notifications */
1496        ret = __clk_speculate_rates(clk, p_rate);
1497
1498        /* abort if a driver objects */
1499        if (ret & NOTIFY_STOP_MASK)
1500                goto out;
1501
1502        /* do the re-parent */
1503        ret = __clk_set_parent(clk, parent, p_index);
1504
1505        /* propagate rate recalculation accordingly */
1506        if (ret)
1507                __clk_recalc_rates(clk, ABORT_RATE_CHANGE);
1508        else
1509                __clk_recalc_rates(clk, POST_RATE_CHANGE);
1510
1511out:
1512        clk_prepare_unlock();
1513
1514        return ret;
1515}
1516EXPORT_SYMBOL_GPL(clk_set_parent);
1517
1518/**
1519 * __clk_init - initialize the data structures in a struct clk
1520 * @dev:        device initializing this clk, placeholder for now
1521 * @clk:        clk being initialized
1522 *
1523 * Initializes the lists in struct clk, queries the hardware for the
1524 * parent and rate and sets them both.
1525 */
1526int __clk_init(struct device *dev, struct clk *clk)
1527{
1528        int i, ret = 0;
1529        struct clk *orphan;
1530        struct hlist_node *tmp2;
1531
1532        if (!clk)
1533                return -EINVAL;
1534
1535        clk_prepare_lock();
1536
1537        /* check to see if a clock with this name is already registered */
1538        if (__clk_lookup(clk->name)) {
1539                pr_debug("%s: clk %s already initialized\n",
1540                                __func__, clk->name);
1541                ret = -EEXIST;
1542                goto out;
1543        }
1544
1545        /* check that clk_ops are sane.  See Documentation/clk.txt */
1546        if (clk->ops->set_rate &&
1547                        !(clk->ops->round_rate && clk->ops->recalc_rate)) {
1548                pr_warning("%s: %s must implement .round_rate & .recalc_rate\n",
1549                                __func__, clk->name);
1550                ret = -EINVAL;
1551                goto out;
1552        }
1553
1554        if (clk->ops->set_parent && !clk->ops->get_parent) {
1555                pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1556                                __func__, clk->name);
1557                ret = -EINVAL;
1558                goto out;
1559        }
1560
1561        /* throw a WARN if any entries in parent_names are NULL */
1562        for (i = 0; i < clk->num_parents; i++)
1563                WARN(!clk->parent_names[i],
1564                                "%s: invalid NULL in %s's .parent_names\n",
1565                                __func__, clk->name);
1566
1567        /*
1568         * Allocate an array of struct clk *'s to avoid unnecessary string
1569         * look-ups of clk's possible parents.  This can fail for clocks passed
1570         * in to clk_init during early boot; thus any access to clk->parents[]
1571         * must always check for a NULL pointer and try to populate it if
1572         * necessary.
1573         *
1574         * If clk->parents is not NULL we skip this entire block.  This allows
1575         * for clock drivers to statically initialize clk->parents.
1576         */
1577        if (clk->num_parents > 1 && !clk->parents) {
1578                clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
1579                                GFP_KERNEL);
1580                /*
1581                 * __clk_lookup returns NULL for parents that have not been
1582                 * clk_init'd; thus any access to clk->parents[] must check
1583                 * for a NULL pointer.  We can always perform lazy lookups for
1584                 * missing parents later on.
1585                 */
1586                if (clk->parents)
1587                        for (i = 0; i < clk->num_parents; i++)
1588                                clk->parents[i] =
1589                                        __clk_lookup(clk->parent_names[i]);
1590        }
1591
1592        clk->parent = __clk_init_parent(clk);
1593
1594        /*
1595         * Populate clk->parent if parent has already been __clk_init'd.  If
1596         * parent has not yet been __clk_init'd then place clk in the orphan
1597         * list.  If clk has set the CLK_IS_ROOT flag then place it in the root
1598         * clk list.
1599         *
1600         * Every time a new clk is clk_init'd then we walk the list of orphan
1601         * clocks and re-parent any that are children of the clock currently
1602         * being clk_init'd.
1603         */
1604        if (clk->parent)
1605                hlist_add_head(&clk->child_node,
1606                                &clk->parent->children);
1607        else if (clk->flags & CLK_IS_ROOT)
1608                hlist_add_head(&clk->child_node, &clk_root_list);
1609        else
1610                hlist_add_head(&clk->child_node, &clk_orphan_list);
1611
1612        /*
1613         * Set clk's rate.  The preferred method is to use .recalc_rate.  For
1614         * simple clocks and lazy developers the default fallback is to use the
1615         * parent's rate.  If a clock doesn't have a parent (or is orphaned)
1616         * then rate is set to zero.
1617         */
1618        if (clk->ops->recalc_rate)
1619                clk->rate = clk->ops->recalc_rate(clk->hw,
1620                                __clk_get_rate(clk->parent));
1621        else if (clk->parent)
1622                clk->rate = clk->parent->rate;
1623        else
1624                clk->rate = 0;
1625
1626        /*
1627         * walk the list of orphan clocks and reparent any that are children of
1628         * this clock
1629         */
1630        hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
1631                if (orphan->ops->get_parent) {
1632                        i = orphan->ops->get_parent(orphan->hw);
1633                        if (!strcmp(clk->name, orphan->parent_names[i]))
1634                                __clk_reparent(orphan, clk);
1635                        continue;
1636                }
1637
1638                for (i = 0; i < orphan->num_parents; i++)
1639                        if (!strcmp(clk->name, orphan->parent_names[i])) {
1640                                __clk_reparent(orphan, clk);
1641                                break;
1642                        }
1643         }
1644
1645        /*
1646         * optional platform-specific magic
1647         *
1648         * The .init callback is not used by any of the basic clock types, but
1649         * exists for weird hardware that must perform initialization magic.
1650         * Please consider other ways of solving initialization problems before
1651         * using this callback, as it's use is discouraged.
1652         */
1653        if (clk->ops->init)
1654                clk->ops->init(clk->hw);
1655
1656        clk_debug_register(clk);
1657
1658out:
1659        clk_prepare_unlock();
1660
1661        return ret;
1662}
1663
1664/**
1665 * __clk_register - register a clock and return a cookie.
1666 *
1667 * Same as clk_register, except that the .clk field inside hw shall point to a
1668 * preallocated (generally statically allocated) struct clk. None of the fields
1669 * of the struct clk need to be initialized.
1670 *
1671 * The data pointed to by .init and .clk field shall NOT be marked as init
1672 * data.
1673 *
1674 * __clk_register is only exposed via clk-private.h and is intended for use with
1675 * very large numbers of clocks that need to be statically initialized.  It is
1676 * a layering violation to include clk-private.h from any code which implements
1677 * a clock's .ops; as such any statically initialized clock data MUST be in a
1678 * separate C file from the logic that implements it's operations.  Returns 0
1679 * on success, otherwise an error code.
1680 */
1681struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
1682{
1683        int ret;
1684        struct clk *clk;
1685
1686        clk = hw->clk;
1687        clk->name = hw->init->name;
1688        clk->ops = hw->init->ops;
1689        clk->hw = hw;
1690        clk->flags = hw->init->flags;
1691        clk->parent_names = hw->init->parent_names;
1692        clk->num_parents = hw->init->num_parents;
1693
1694        ret = __clk_init(dev, clk);
1695        if (ret)
1696                return ERR_PTR(ret);
1697
1698        return clk;
1699}
1700EXPORT_SYMBOL_GPL(__clk_register);
1701
1702static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk)
1703{
1704        int i, ret;
1705
1706        clk->name = kstrdup(hw->init->name, GFP_KERNEL);
1707        if (!clk->name) {
1708                pr_err("%s: could not allocate clk->name\n", __func__);
1709                ret = -ENOMEM;
1710                goto fail_name;
1711        }
1712        clk->ops = hw->init->ops;
1713        clk->hw = hw;
1714        clk->flags = hw->init->flags;
1715        clk->num_parents = hw->init->num_parents;
1716        hw->clk = clk;
1717
1718        /* allocate local copy in case parent_names is __initdata */
1719        clk->parent_names = kzalloc((sizeof(char*) * clk->num_parents),
1720                        GFP_KERNEL);
1721
1722        if (!clk->parent_names) {
1723                pr_err("%s: could not allocate clk->parent_names\n", __func__);
1724                ret = -ENOMEM;
1725                goto fail_parent_names;
1726        }
1727
1728
1729        /* copy each string name in case parent_names is __initdata */
1730        for (i = 0; i < clk->num_parents; i++) {
1731                clk->parent_names[i] = kstrdup(hw->init->parent_names[i],
1732                                                GFP_KERNEL);
1733                if (!clk->parent_names[i]) {
1734                        pr_err("%s: could not copy parent_names\n", __func__);
1735                        ret = -ENOMEM;
1736                        goto fail_parent_names_copy;
1737                }
1738        }
1739
1740        ret = __clk_init(dev, clk);
1741        if (!ret)
1742                return 0;
1743
1744fail_parent_names_copy:
1745        while (--i >= 0)
1746                kfree(clk->parent_names[i]);
1747        kfree(clk->parent_names);
1748fail_parent_names:
1749        kfree(clk->name);
1750fail_name:
1751        return ret;
1752}
1753
1754/**
1755 * clk_register - allocate a new clock, register it and return an opaque cookie
1756 * @dev: device that is registering this clock
1757 * @hw: link to hardware-specific clock data
1758 *
1759 * clk_register is the primary interface for populating the clock tree with new
1760 * clock nodes.  It returns a pointer to the newly allocated struct clk which
1761 * cannot be dereferenced by driver code but may be used in conjuction with the
1762 * rest of the clock API.  In the event of an error clk_register will return an
1763 * error code; drivers must test for an error code after calling clk_register.
1764 */
1765struct clk *clk_register(struct device *dev, struct clk_hw *hw)
1766{
1767        int ret;
1768        struct clk *clk;
1769
1770        clk = kzalloc(sizeof(*clk), GFP_KERNEL);
1771        if (!clk) {
1772                pr_err("%s: could not allocate clk\n", __func__);
1773                ret = -ENOMEM;
1774                goto fail_out;
1775        }
1776
1777        ret = _clk_register(dev, hw, clk);
1778        if (!ret)
1779                return clk;
1780
1781        kfree(clk);
1782fail_out:
1783        return ERR_PTR(ret);
1784}
1785EXPORT_SYMBOL_GPL(clk_register);
1786
1787/**
1788 * clk_unregister - unregister a currently registered clock
1789 * @clk: clock to unregister
1790 *
1791 * Currently unimplemented.
1792 */
1793void clk_unregister(struct clk *clk) {}
1794EXPORT_SYMBOL_GPL(clk_unregister);
1795
1796static void devm_clk_release(struct device *dev, void *res)
1797{
1798        clk_unregister(res);
1799}
1800
1801/**
1802 * devm_clk_register - resource managed clk_register()
1803 * @dev: device that is registering this clock
1804 * @hw: link to hardware-specific clock data
1805 *
1806 * Managed clk_register(). Clocks returned from this function are
1807 * automatically clk_unregister()ed on driver detach. See clk_register() for
1808 * more information.
1809 */
1810struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
1811{
1812        struct clk *clk;
1813        int ret;
1814
1815        clk = devres_alloc(devm_clk_release, sizeof(*clk), GFP_KERNEL);
1816        if (!clk)
1817                return ERR_PTR(-ENOMEM);
1818
1819        ret = _clk_register(dev, hw, clk);
1820        if (!ret) {
1821                devres_add(dev, clk);
1822        } else {
1823                devres_free(clk);
1824                clk = ERR_PTR(ret);
1825        }
1826
1827        return clk;
1828}
1829EXPORT_SYMBOL_GPL(devm_clk_register);
1830
1831static int devm_clk_match(struct device *dev, void *res, void *data)
1832{
1833        struct clk *c = res;
1834        if (WARN_ON(!c))
1835                return 0;
1836        return c == data;
1837}
1838
1839/**
1840 * devm_clk_unregister - resource managed clk_unregister()
1841 * @clk: clock to unregister
1842 *
1843 * Deallocate a clock allocated with devm_clk_register(). Normally
1844 * this function will not need to be called and the resource management
1845 * code will ensure that the resource is freed.
1846 */
1847void devm_clk_unregister(struct device *dev, struct clk *clk)
1848{
1849        WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
1850}
1851EXPORT_SYMBOL_GPL(devm_clk_unregister);
1852
1853/***        clk rate change notifiers        ***/
1854
1855/**
1856 * clk_notifier_register - add a clk rate change notifier
1857 * @clk: struct clk * to watch
1858 * @nb: struct notifier_block * with callback info
1859 *
1860 * Request notification when clk's rate changes.  This uses an SRCU
1861 * notifier because we want it to block and notifier unregistrations are
1862 * uncommon.  The callbacks associated with the notifier must not
1863 * re-enter into the clk framework by calling any top-level clk APIs;
1864 * this will cause a nested prepare_lock mutex.
1865 *
1866 * Pre-change notifier callbacks will be passed the current, pre-change
1867 * rate of the clk via struct clk_notifier_data.old_rate.  The new,
1868 * post-change rate of the clk is passed via struct
1869 * clk_notifier_data.new_rate.
1870 *
1871 * Post-change notifiers will pass the now-current, post-change rate of
1872 * the clk in both struct clk_notifier_data.old_rate and struct
1873 * clk_notifier_data.new_rate.
1874 *
1875 * Abort-change notifiers are effectively the opposite of pre-change
1876 * notifiers: the original pre-change clk rate is passed in via struct
1877 * clk_notifier_data.new_rate and the failed post-change rate is passed
1878 * in via struct clk_notifier_data.old_rate.
1879 *
1880 * clk_notifier_register() must be called from non-atomic context.
1881 * Returns -EINVAL if called with null arguments, -ENOMEM upon
1882 * allocation failure; otherwise, passes along the return value of
1883 * srcu_notifier_chain_register().
1884 */
1885int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
1886{
1887        struct clk_notifier *cn;
1888        int ret = -ENOMEM;
1889
1890        if (!clk || !nb)
1891                return -EINVAL;
1892
1893        clk_prepare_lock();
1894
1895        /* search the list of notifiers for this clk */
1896        list_for_each_entry(cn, &clk_notifier_list, node)
1897                if (cn->clk == clk)
1898                        break;
1899
1900        /* if clk wasn't in the notifier list, allocate new clk_notifier */
1901        if (cn->clk != clk) {
1902                cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
1903                if (!cn)
1904                        goto out;
1905
1906                cn->clk = clk;
1907                srcu_init_notifier_head(&cn->notifier_head);
1908
1909                list_add(&cn->node, &clk_notifier_list);
1910        }
1911
1912        ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
1913
1914        clk->notifier_count++;
1915
1916out:
1917        clk_prepare_unlock();
1918
1919        return ret;
1920}
1921EXPORT_SYMBOL_GPL(clk_notifier_register);
1922
1923/**
1924 * clk_notifier_unregister - remove a clk rate change notifier
1925 * @clk: struct clk *
1926 * @nb: struct notifier_block * with callback info
1927 *
1928 * Request no further notification for changes to 'clk' and frees memory
1929 * allocated in clk_notifier_register.
1930 *
1931 * Returns -EINVAL if called with null arguments; otherwise, passes
1932 * along the return value of srcu_notifier_chain_unregister().
1933 */
1934int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
1935{
1936        struct clk_notifier *cn = NULL;
1937        int ret = -EINVAL;
1938
1939        if (!clk || !nb)
1940                return -EINVAL;
1941
1942        clk_prepare_lock();
1943
1944        list_for_each_entry(cn, &clk_notifier_list, node)
1945                if (cn->clk == clk)
1946                        break;
1947
1948        if (cn->clk == clk) {
1949                ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
1950
1951                clk->notifier_count--;
1952
1953                /* XXX the notifier code should handle this better */
1954                if (!cn->notifier_head.head) {
1955                        srcu_cleanup_notifier_head(&cn->notifier_head);
1956                        list_del(&cn->node);
1957                        kfree(cn);
1958                }
1959
1960        } else {
1961                ret = -ENOENT;
1962        }
1963
1964        clk_prepare_unlock();
1965
1966        return ret;
1967}
1968EXPORT_SYMBOL_GPL(clk_notifier_unregister);
1969
1970#ifdef CONFIG_OF
1971/**
1972 * struct of_clk_provider - Clock provider registration structure
1973 * @link: Entry in global list of clock providers
1974 * @node: Pointer to device tree node of clock provider
1975 * @get: Get clock callback.  Returns NULL or a struct clk for the
1976 *       given clock specifier
1977 * @data: context pointer to be passed into @get callback
1978 */
1979struct of_clk_provider {
1980        struct list_head link;
1981
1982        struct device_node *node;
1983        struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
1984        void *data;
1985};
1986
1987extern struct of_device_id __clk_of_table[];
1988
1989static const struct of_device_id __clk_of_table_sentinel
1990        __used __section(__clk_of_table_end);
1991
1992static LIST_HEAD(of_clk_providers);
1993static DEFINE_MUTEX(of_clk_lock);
1994
1995struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
1996                                     void *data)
1997{
1998        return data;
1999}
2000EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
2001
2002struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
2003{
2004        struct clk_onecell_data *clk_data = data;
2005        unsigned int idx = clkspec->args[0];
2006
2007        if (idx >= clk_data->clk_num) {
2008                pr_err("%s: invalid clock index %d\n", __func__, idx);
2009                return ERR_PTR(-EINVAL);
2010        }
2011
2012        return clk_data->clks[idx];
2013}
2014EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
2015
2016/**
2017 * of_clk_add_provider() - Register a clock provider for a node
2018 * @np: Device node pointer associated with clock provider
2019 * @clk_src_get: callback for decoding clock
2020 * @data: context pointer for @clk_src_get callback.
2021 */
2022int of_clk_add_provider(struct device_node *np,
2023                        struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
2024                                                   void *data),
2025                        void *data)
2026{
2027        struct of_clk_provider *cp;
2028
2029        cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
2030        if (!cp)
2031                return -ENOMEM;
2032
2033        cp->node = of_node_get(np);
2034        cp->data = data;
2035        cp->get = clk_src_get;
2036
2037        mutex_lock(&of_clk_lock);
2038        list_add(&cp->link, &of_clk_providers);
2039        mutex_unlock(&of_clk_lock);
2040        pr_debug("Added clock from %s\n", np->full_name);
2041
2042        return 0;
2043}
2044EXPORT_SYMBOL_GPL(of_clk_add_provider);
2045
2046/**
2047 * of_clk_del_provider() - Remove a previously registered clock provider
2048 * @np: Device node pointer associated with clock provider
2049 */
2050void of_clk_del_provider(struct device_node *np)
2051{
2052        struct of_clk_provider *cp;
2053
2054        mutex_lock(&of_clk_lock);
2055        list_for_each_entry(cp, &of_clk_providers, link) {
2056                if (cp->node == np) {
2057                        list_del(&cp->link);
2058                        of_node_put(cp->node);
2059                        kfree(cp);
2060                        break;
2061                }
2062        }
2063        mutex_unlock(&of_clk_lock);
2064}
2065EXPORT_SYMBOL_GPL(of_clk_del_provider);
2066
2067struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
2068{
2069        struct of_clk_provider *provider;
2070        struct clk *clk = ERR_PTR(-ENOENT);
2071
2072        /* Check if we have such a provider in our array */
2073        mutex_lock(&of_clk_lock);
2074        list_for_each_entry(provider, &of_clk_providers, link) {
2075                if (provider->node == clkspec->np)
2076                        clk = provider->get(clkspec, provider->data);
2077                if (!IS_ERR(clk))
2078                        break;
2079        }
2080        mutex_unlock(&of_clk_lock);
2081
2082        return clk;
2083}
2084
2085const char *of_clk_get_parent_name(struct device_node *np, int index)
2086{
2087        struct of_phandle_args clkspec;
2088        const char *clk_name;
2089        int rc;
2090
2091        if (index < 0)
2092                return NULL;
2093
2094        rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
2095                                        &clkspec);
2096        if (rc)
2097                return NULL;
2098
2099        if (of_property_read_string_index(clkspec.np, "clock-output-names",
2100                                          clkspec.args_count ? clkspec.args[0] : 0,
2101                                          &clk_name) < 0)
2102                clk_name = clkspec.np->name;
2103
2104        of_node_put(clkspec.np);
2105        return clk_name;
2106}
2107EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
2108
2109/**
2110 * of_clk_init() - Scan and init clock providers from the DT
2111 * @matches: array of compatible values and init functions for providers.
2112 *
2113 * This function scans the device tree for matching clock providers and
2114 * calls their initialization functions
2115 */
2116void __init of_clk_init(const struct of_device_id *matches)
2117{
2118        struct device_node *np;
2119
2120        if (!matches)
2121                matches = __clk_of_table;
2122
2123        for_each_matching_node(np, matches) {
2124                const struct of_device_id *match = of_match_node(matches, np);
2125                of_clk_init_cb_t clk_init_cb = match->data;
2126                clk_init_cb(np);
2127        }
2128}
2129#endif
2130
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.