arch/sh/kernel/cpu/clock.c

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