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   1 /*
   2  * arch/sh/kernel/cpu/clock.c - SuperH clock framework
   3  *
   4  *  Copyright (C) 2005 - 2009  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  *  With clkdev bits:
  14  *
  15  *      Copyright (C) 2008 Russell King.
  16  *
  17  * This file is subject to the terms and conditions of the GNU General Public
  18  * License.  See the file "COPYING" in the main directory of this archive
  19  * for more details.
  20  */
  21 #include <linux/kernel.h>
  22 #include <linux/init.h>
  23 #include <linux/module.h>
  24 #include <linux/mutex.h>
  25 #include <linux/list.h>
  26 #include <linux/kobject.h>
  27 #include <linux/sysdev.h>
  28 #include <linux/seq_file.h>
  29 #include <linux/err.h>
  30 #include <linux/platform_device.h>
  31 #include <linux/proc_fs.h>
  32 #include <asm/clock.h>
  33
  34 static LIST_HEAD(clock_list);
  35 static DEFINE_SPINLOCK(clock_lock);
  36 static DEFINE_MUTEX(clock_list_sem);
  37
  38 /*
  39  * Each subtype is expected to define the init routines for these clocks,
  40  * as each subtype (or processor family) will have these clocks at the
  41  * very least. These are all provided through the CPG, which even some of
  42  * the more quirky parts (such as ST40, SH4-202, etc.) still have.
  43  *
  44  * The processor-specific code is expected to register any additional
  45  * clock sources that are of interest.
  46  */
  47 static struct clk master_clk = {
  48         .name           = "master_clk",
  49         .flags          = CLK_ENABLE_ON_INIT,
  50         .rate           = CONFIG_SH_PCLK_FREQ,
  51 };
  52
  53 static struct clk peripheral_clk = {
  54         .name           = "peripheral_clk",
  55         .parent         = &master_clk,
  56         .flags          = CLK_ENABLE_ON_INIT,
  57 };
  58
  59 static struct clk bus_clk = {
  60         .name           = "bus_clk",
  61         .parent         = &master_clk,
  62         .flags          = CLK_ENABLE_ON_INIT,
  63 };
  64
  65 static struct clk cpu_clk = {
  66         .name           = "cpu_clk",
  67         .parent         = &master_clk,
  68         .flags          = CLK_ENABLE_ON_INIT,
  69 };
  70
  71 /*
  72  * The ordering of these clocks matters, do not change it.
  73  */
  74 static struct clk *onchip_clocks[] = {
  75         &master_clk,
  76         &peripheral_clk,
  77         &bus_clk,
  78         &cpu_clk,
  79 };
  80
  81 /* Used for clocks that always have same value as the parent clock */
  82 unsigned long followparent_recalc(struct clk *clk)
  83 {
  84         return clk->parent->rate;
  85 }
  86
  87 int clk_reparent(struct clk *child, struct clk *parent)
  88 {
  89         list_del_init(&child->sibling);
  90         if (parent)
  91                 list_add(&child->sibling, &parent->children);
  92         child->parent = parent;
  93
  94         /* now do the debugfs renaming to reattach the child
  95            to the proper parent */
  96
  97         return 0;
  98 }
  99
 100 /* Propagate rate to children */
 101 void propagate_rate(struct clk *tclk)
 102 {
 103         struct clk *clkp;
 104
 105         list_for_each_entry(clkp, &tclk->children, sibling) {
 106                 if (clkp->ops && clkp->ops->recalc)
 107                         clkp->rate = clkp->ops->recalc(clkp);
 108                 propagate_rate(clkp);
 109         }
 110 }
 111
 112 static void __clk_disable(struct clk *clk)
 113 {
 114         if (clk->usecount == 0) {
 115                 printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
 116                        clk->name);
 117                 WARN_ON(1);
 118                 return;
 119         }
 120
 121         if (!(--clk->usecount)) {
 122                 if (likely(clk->ops && clk->ops->disable))
 123                         clk->ops->disable(clk);
 124                 if (likely(clk->parent))
 125                         __clk_disable(clk->parent);
 126         }
 127 }
 128
 129 void clk_disable(struct clk *clk)
 130 {
 131         unsigned long flags;
 132
 133         if (!clk)
 134                 return;
 135
 136         spin_lock_irqsave(&clock_lock, flags);
 137         __clk_disable(clk);
 138         spin_unlock_irqrestore(&clock_lock, flags);
 139 }
 140 EXPORT_SYMBOL_GPL(clk_disable);
 141
 142 static int __clk_enable(struct clk *clk)
 143 {
 144         int ret = 0;
 145
 146         if (clk->usecount++ == 0) {
 147                 if (clk->parent) {
 148                         ret = __clk_enable(clk->parent);
 149                         if (unlikely(ret))
 150                                 goto err;
 151                 }
 152
 153                 if (clk->ops && clk->ops->enable) {
 154                         ret = clk->ops->enable(clk);
 155                         if (ret) {
 156                                 if (clk->parent)
 157                                         __clk_disable(clk->parent);
 158                                 goto err;
 159                         }
 160                 }
 161         }
 162
 163         return ret;
 164 err:
 165         clk->usecount--;
 166         return ret;
 167 }
 168
 169 int clk_enable(struct clk *clk)
 170 {
 171         unsigned long flags;
 172         int ret;
 173
 174         if (!clk)
 175                 return -EINVAL;
 176
 177         spin_lock_irqsave(&clock_lock, flags);
 178         ret = __clk_enable(clk);
 179         spin_unlock_irqrestore(&clock_lock, flags);
 180
 181         return ret;
 182 }
 183 EXPORT_SYMBOL_GPL(clk_enable);
 184
 185 static LIST_HEAD(root_clks);
 186
 187 /**
 188  * recalculate_root_clocks - recalculate and propagate all root clocks
 189  *
 190  * Recalculates all root clocks (clocks with no parent), which if the
 191  * clock's .recalc is set correctly, should also propagate their rates.
 192  * Called at init.
 193  */
 194 void recalculate_root_clocks(void)
 195 {
 196         struct clk *clkp;
 197
 198         list_for_each_entry(clkp, &root_clks, sibling) {
 199                 if (clkp->ops && clkp->ops->recalc)
 200                         clkp->rate = clkp->ops->recalc(clkp);
 201                 propagate_rate(clkp);
 202         }
 203 }
 204
 205 int clk_register(struct clk *clk)
 206 {
 207         if (clk == NULL || IS_ERR(clk))
 208                 return -EINVAL;
 209
 210         /*
 211          * trap out already registered clocks
 212          */
 213         if (clk->node.next || clk->node.prev)
 214                 return 0;
 215
 216         mutex_lock(&clock_list_sem);
 217
 218         INIT_LIST_HEAD(&clk->children);
 219         clk->usecount = 0;
 220
 221         if (clk->parent)
 222                 list_add(&clk->sibling, &clk->parent->children);
 223         else
 224                 list_add(&clk->sibling, &root_clks);
 225
 226         list_add(&clk->node, &clock_list);
 227         if (clk->ops && clk->ops->init)
 228                 clk->ops->init(clk);
 229         mutex_unlock(&clock_list_sem);
 230
 231         return 0;
 232 }
 233 EXPORT_SYMBOL_GPL(clk_register);
 234
 235 void clk_unregister(struct clk *clk)
 236 {
 237         mutex_lock(&clock_list_sem);
 238         list_del(&clk->sibling);
 239         list_del(&clk->node);
 240         mutex_unlock(&clock_list_sem);
 241 }
 242 EXPORT_SYMBOL_GPL(clk_unregister);
 243
 244 static void clk_enable_init_clocks(void)
 245 {
 246         struct clk *clkp;
 247
 248         list_for_each_entry(clkp, &clock_list, node)
 249                 if (clkp->flags & CLK_ENABLE_ON_INIT)
 250                         clk_enable(clkp);
 251 }
 252
 253 unsigned long clk_get_rate(struct clk *clk)
 254 {
 255         return clk->rate;
 256 }
 257 EXPORT_SYMBOL_GPL(clk_get_rate);
 258
 259 int clk_set_rate(struct clk *clk, unsigned long rate)
 260 {
 261         return clk_set_rate_ex(clk, rate, 0);
 262 }
 263 EXPORT_SYMBOL_GPL(clk_set_rate);
 264
 265 int clk_set_rate_ex(struct clk *clk, unsigned long rate, int algo_id)
 266 {
 267         int ret = -EOPNOTSUPP;
 268
 269         if (likely(clk->ops && clk->ops->set_rate)) {
 270                 unsigned long flags;
 271
 272                 spin_lock_irqsave(&clock_lock, flags);
 273                 ret = clk->ops->set_rate(clk, rate, algo_id);
 274                 if (ret == 0) {
 275                         if (clk->ops->recalc)
 276                                 clk->rate = clk->ops->recalc(clk);
 277                         propagate_rate(clk);
 278                 }
 279                 spin_unlock_irqrestore(&clock_lock, flags);
 280         }
 281
 282         return ret;
 283 }
 284 EXPORT_SYMBOL_GPL(clk_set_rate_ex);
 285
 286 int clk_set_parent(struct clk *clk, struct clk *parent)
 287 {
 288         unsigned long flags;
 289         int ret = -EINVAL;
 290
 291         if (!parent || !clk)
 292                 return ret;
 293         if (clk->parent == parent)
 294                 return 0;
 295
 296         spin_lock_irqsave(&clock_lock, flags);
 297         if (clk->usecount == 0) {
 298                 if (clk->ops->set_parent)
 299                         ret = clk->ops->set_parent(clk, parent);
 300                 else
 301                         ret = clk_reparent(clk, parent);
 302
 303                 if (ret == 0) {
 304                         pr_debug("clock: set parent of %s to %s (new rate %ld)\n",
 305                                  clk->name, clk->parent->name, clk->rate);
 306                         if (clk->ops->recalc)
 307                                 clk->rate = clk->ops->recalc(clk);
 308                         propagate_rate(clk);
 309                 }
 310         } else
 311                 ret = -EBUSY;
 312         spin_unlock_irqrestore(&clock_lock, flags);
 313
 314         return ret;
 315 }
 316 EXPORT_SYMBOL_GPL(clk_set_parent);
 317
 318 struct clk *clk_get_parent(struct clk *clk)
 319 {
 320         return clk->parent;
 321 }
 322 EXPORT_SYMBOL_GPL(clk_get_parent);
 323
 324 long clk_round_rate(struct clk *clk, unsigned long rate)
 325 {
 326         if (likely(clk->ops && clk->ops->round_rate)) {
 327                 unsigned long flags, rounded;
 328
 329                 spin_lock_irqsave(&clock_lock, flags);
 330                 rounded = clk->ops->round_rate(clk, rate);
 331                 spin_unlock_irqrestore(&clock_lock, flags);
 332
 333                 return rounded;
 334         }
 335
 336         return clk_get_rate(clk);
 337 }
 338 EXPORT_SYMBOL_GPL(clk_round_rate);
 339
 340 /*
 341  * Find the correct struct clk for the device and connection ID.
 342  * We do slightly fuzzy matching here:
 343  *  An entry with a NULL ID is assumed to be a wildcard.
 344  *  If an entry has a device ID, it must match
 345  *  If an entry has a connection ID, it must match
 346  * Then we take the most specific entry - with the following
 347  * order of precidence: dev+con > dev only > con only.
 348  */
 349 static struct clk *clk_find(const char *dev_id, const char *con_id)
 350 {
 351         struct clk_lookup *p;
 352         struct clk *clk = NULL;
 353         int match, best = 0;
 354
 355         list_for_each_entry(p, &clock_list, node) {
 356                 match = 0;
 357                 if (p->dev_id) {
 358                         if (!dev_id || strcmp(p->dev_id, dev_id))
 359                                 continue;
 360                         match += 2;
 361                 }
 362                 if (p->con_id) {
 363                         if (!con_id || strcmp(p->con_id, con_id))
 364                                 continue;
 365                         match += 1;
 366                 }
 367                 if (match == 0)
 368                         continue;
 369
 370                 if (match > best) {
 371                         clk = p->clk;
 372                         best = match;
 373                 }
 374         }
 375         return clk;
 376 }
 377
 378 struct clk *clk_get_sys(const char *dev_id, const char *con_id)
 379 {
 380         struct clk *clk;
 381
 382         mutex_lock(&clock_list_sem);
 383         clk = clk_find(dev_id, con_id);
 384         mutex_unlock(&clock_list_sem);
 385
 386         return clk ? clk : ERR_PTR(-ENOENT);
 387 }
 388 EXPORT_SYMBOL_GPL(clk_get_sys);
 389
 390 /*
 391  * Returns a clock. Note that we first try to use device id on the bus
 392  * and clock name. If this fails, we try to use clock name only.
 393  */
 394 struct clk *clk_get(struct device *dev, const char *id)
 395 {
 396         const char *dev_id = dev ? dev_name(dev) : NULL;
 397         struct clk *p, *clk = ERR_PTR(-ENOENT);
 398         int idno;
 399
 400         clk = clk_get_sys(dev_id, id);
 401         if (clk && !IS_ERR(clk))
 402                 return clk;
 403
 404         if (dev == NULL || dev->bus != &platform_bus_type)
 405                 idno = -1;
 406         else
 407                 idno = to_platform_device(dev)->id;
 408
 409         mutex_lock(&clock_list_sem);
 410         list_for_each_entry(p, &clock_list, node) {
 411                 if (p->id == idno &&
 412                     strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
 413                         clk = p;
 414                         goto found;
 415                 }
 416         }
 417
 418         list_for_each_entry(p, &clock_list, node) {
 419                 if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
 420                         clk = p;
 421                         break;
 422                 }
 423         }
 424
 425 found:
 426         mutex_unlock(&clock_list_sem);
 427
 428         return clk;
 429 }
 430 EXPORT_SYMBOL_GPL(clk_get);
 431
 432 void clk_put(struct clk *clk)
 433 {
 434         if (clk && !IS_ERR(clk))
 435                 module_put(clk->owner);
 436 }
 437 EXPORT_SYMBOL_GPL(clk_put);
 438
 439 int __init __weak arch_clk_init(void)
 440 {
 441         return 0;
 442 }
 443
 444 static int show_clocks(char *buf, char **start, off_t off,
 445                        int len, int *eof, void *data)
 446 {
 447         struct clk *clk;
 448         char *p = buf;
 449
 450         list_for_each_entry_reverse(clk, &clock_list, node) {
 451                 unsigned long rate = clk_get_rate(clk);
 452
 453                 p += sprintf(p, "%-12s\t: %ld.%02ldMHz\t%s\n", clk->name,
 454                              rate / 1000000, (rate % 1000000) / 10000,
 455                               (clk->usecount > 0) ?  "enabled" : "disabled");
 456         }
 457
 458         return p - buf;
 459 }
 460
 461 #ifdef CONFIG_PM
 462 static int clks_sysdev_suspend(struct sys_device *dev, pm_message_t state)
 463 {
 464         static pm_message_t prev_state;
 465         struct clk *clkp;
 466
 467         switch (state.event) {
 468         case PM_EVENT_ON:
 469                 /* Resumeing from hibernation */
 470                 if (prev_state.event != PM_EVENT_FREEZE)
 471                         break;
 472
 473                 list_for_each_entry(clkp, &clock_list, node) {
 474                         if (likely(clkp->ops)) {
 475                                 unsigned long rate = clkp->rate;
 476
 477                                 if (likely(clkp->ops->set_parent))
 478                                         clkp->ops->set_parent(clkp,
 479                                                 clkp->parent);
 480                                 if (likely(clkp->ops->set_rate))
 481                                         clkp->ops->set_rate(clkp,
 482                                                 rate, NO_CHANGE);
 483                                 else if (likely(clkp->ops->recalc))
 484                                         clkp->rate = clkp->ops->recalc(clkp);
 485                         }
 486                 }
 487                 break;
 488         case PM_EVENT_FREEZE:
 489                 break;
 490         case PM_EVENT_SUSPEND:
 491                 break;
 492         }
 493
 494         prev_state = state;
 495         return 0;
 496 }
 497
 498 static int clks_sysdev_resume(struct sys_device *dev)
 499 {
 500         return clks_sysdev_suspend(dev, PMSG_ON);
 501 }
 502
 503 static struct sysdev_class clks_sysdev_class = {
 504         .name = "clks",
 505 };
 506
 507 static struct sysdev_driver clks_sysdev_driver = {
 508         .suspend = clks_sysdev_suspend,
 509         .resume = clks_sysdev_resume,
 510 };
 511
 512 static struct sys_device clks_sysdev_dev = {
 513         .cls = &clks_sysdev_class,
 514 };
 515
 516 static int __init clk_sysdev_init(void)
 517 {
 518         sysdev_class_register(&clks_sysdev_class);
 519         sysdev_driver_register(&clks_sysdev_class, &clks_sysdev_driver);
 520         sysdev_register(&clks_sysdev_dev);
 521
 522         return 0;
 523 }
 524 subsys_initcall(clk_sysdev_init);
 525 #endif
 526
 527 int __init clk_init(void)
 528 {
 529         int i, ret = 0;
 530
 531         BUG_ON(!master_clk.rate);
 532
 533         for (i = 0; i < ARRAY_SIZE(onchip_clocks); i++) {
 534                 struct clk *clk = onchip_clocks[i];
 535
 536                 arch_init_clk_ops(&clk->ops, i);
 537                 ret |= clk_register(clk);
 538         }
 539
 540         ret |= arch_clk_init();
 541
 542         /* Kick the child clocks.. */
 543         recalculate_root_clocks();
 544
 545         /* Enable the necessary init clocks */
 546         clk_enable_init_clocks();
 547
 548         return ret;
 549 }
 550
 551 static int __init clk_proc_init(void)
 552 {
 553         struct proc_dir_entry *p;
 554         p = create_proc_read_entry("clocks", S_IRUSR, NULL,
 555                                    show_clocks, NULL);
 556         if (unlikely(!p))
 557                 return -EINVAL;
 558
 559         return 0;
 560 }
 561 subsys_initcall(clk_proc_init);