Mike Turquette | b2476490 | 2012-03-15 23:11:19 -0700 | [diff] [blame] | 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 | |
| 20 | static DEFINE_SPINLOCK(enable_lock); |
| 21 | static DEFINE_MUTEX(prepare_lock); |
| 22 | |
| 23 | static HLIST_HEAD(clk_root_list); |
| 24 | static HLIST_HEAD(clk_orphan_list); |
| 25 | static LIST_HEAD(clk_notifier_list); |
| 26 | |
| 27 | /*** debugfs support ***/ |
| 28 | |
| 29 | #ifdef CONFIG_COMMON_CLK_DEBUG |
| 30 | #include <linux/debugfs.h> |
| 31 | |
| 32 | static struct dentry *rootdir; |
| 33 | static struct dentry *orphandir; |
| 34 | static int inited = 0; |
| 35 | |
| 36 | /* caller must hold prepare_lock */ |
| 37 | static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry) |
| 38 | { |
| 39 | struct dentry *d; |
| 40 | int ret = -ENOMEM; |
| 41 | |
| 42 | if (!clk || !pdentry) { |
| 43 | ret = -EINVAL; |
| 44 | goto out; |
| 45 | } |
| 46 | |
| 47 | d = debugfs_create_dir(clk->name, pdentry); |
| 48 | if (!d) |
| 49 | goto out; |
| 50 | |
| 51 | clk->dentry = d; |
| 52 | |
| 53 | d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry, |
| 54 | (u32 *)&clk->rate); |
| 55 | if (!d) |
| 56 | goto err_out; |
| 57 | |
| 58 | d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry, |
| 59 | (u32 *)&clk->flags); |
| 60 | if (!d) |
| 61 | goto err_out; |
| 62 | |
| 63 | d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry, |
| 64 | (u32 *)&clk->prepare_count); |
| 65 | if (!d) |
| 66 | goto err_out; |
| 67 | |
| 68 | d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry, |
| 69 | (u32 *)&clk->enable_count); |
| 70 | if (!d) |
| 71 | goto err_out; |
| 72 | |
| 73 | d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry, |
| 74 | (u32 *)&clk->notifier_count); |
| 75 | if (!d) |
| 76 | goto err_out; |
| 77 | |
| 78 | ret = 0; |
| 79 | goto out; |
| 80 | |
| 81 | err_out: |
| 82 | debugfs_remove(clk->dentry); |
| 83 | out: |
| 84 | return ret; |
| 85 | } |
| 86 | |
| 87 | /* caller must hold prepare_lock */ |
| 88 | static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry) |
| 89 | { |
| 90 | struct clk *child; |
| 91 | struct hlist_node *tmp; |
| 92 | int ret = -EINVAL;; |
| 93 | |
| 94 | if (!clk || !pdentry) |
| 95 | goto out; |
| 96 | |
| 97 | ret = clk_debug_create_one(clk, pdentry); |
| 98 | |
| 99 | if (ret) |
| 100 | goto out; |
| 101 | |
| 102 | hlist_for_each_entry(child, tmp, &clk->children, child_node) |
| 103 | clk_debug_create_subtree(child, clk->dentry); |
| 104 | |
| 105 | ret = 0; |
| 106 | out: |
| 107 | return ret; |
| 108 | } |
| 109 | |
| 110 | /** |
| 111 | * clk_debug_register - add a clk node to the debugfs clk tree |
| 112 | * @clk: the clk being added to the debugfs clk tree |
| 113 | * |
| 114 | * Dynamically adds a clk to the debugfs clk tree if debugfs has been |
| 115 | * initialized. Otherwise it bails out early since the debugfs clk tree |
| 116 | * will be created lazily by clk_debug_init as part of a late_initcall. |
| 117 | * |
| 118 | * Caller must hold prepare_lock. Only clk_init calls this function (so |
| 119 | * far) so this is taken care. |
| 120 | */ |
| 121 | static int clk_debug_register(struct clk *clk) |
| 122 | { |
| 123 | struct clk *parent; |
| 124 | struct dentry *pdentry; |
| 125 | int ret = 0; |
| 126 | |
| 127 | if (!inited) |
| 128 | goto out; |
| 129 | |
| 130 | parent = clk->parent; |
| 131 | |
| 132 | /* |
| 133 | * Check to see if a clk is a root clk. Also check that it is |
| 134 | * safe to add this clk to debugfs |
| 135 | */ |
| 136 | if (!parent) |
| 137 | if (clk->flags & CLK_IS_ROOT) |
| 138 | pdentry = rootdir; |
| 139 | else |
| 140 | pdentry = orphandir; |
| 141 | else |
| 142 | if (parent->dentry) |
| 143 | pdentry = parent->dentry; |
| 144 | else |
| 145 | goto out; |
| 146 | |
| 147 | ret = clk_debug_create_subtree(clk, pdentry); |
| 148 | |
| 149 | out: |
| 150 | return ret; |
| 151 | } |
| 152 | |
| 153 | /** |
| 154 | * clk_debug_init - lazily create the debugfs clk tree visualization |
| 155 | * |
| 156 | * clks are often initialized very early during boot before memory can |
| 157 | * be dynamically allocated and well before debugfs is setup. |
| 158 | * clk_debug_init walks the clk tree hierarchy while holding |
| 159 | * prepare_lock and creates the topology as part of a late_initcall, |
| 160 | * thus insuring that clks initialized very early will still be |
| 161 | * represented in the debugfs clk tree. This function should only be |
| 162 | * called once at boot-time, and all other clks added dynamically will |
| 163 | * be done so with clk_debug_register. |
| 164 | */ |
| 165 | static int __init clk_debug_init(void) |
| 166 | { |
| 167 | struct clk *clk; |
| 168 | struct hlist_node *tmp; |
| 169 | |
| 170 | rootdir = debugfs_create_dir("clk", NULL); |
| 171 | |
| 172 | if (!rootdir) |
| 173 | return -ENOMEM; |
| 174 | |
| 175 | orphandir = debugfs_create_dir("orphans", rootdir); |
| 176 | |
| 177 | if (!orphandir) |
| 178 | return -ENOMEM; |
| 179 | |
| 180 | mutex_lock(&prepare_lock); |
| 181 | |
| 182 | hlist_for_each_entry(clk, tmp, &clk_root_list, child_node) |
| 183 | clk_debug_create_subtree(clk, rootdir); |
| 184 | |
| 185 | hlist_for_each_entry(clk, tmp, &clk_orphan_list, child_node) |
| 186 | clk_debug_create_subtree(clk, orphandir); |
| 187 | |
| 188 | inited = 1; |
| 189 | |
| 190 | mutex_unlock(&prepare_lock); |
| 191 | |
| 192 | return 0; |
| 193 | } |
| 194 | late_initcall(clk_debug_init); |
| 195 | #else |
| 196 | static inline int clk_debug_register(struct clk *clk) { return 0; } |
| 197 | #endif /* CONFIG_COMMON_CLK_DEBUG */ |
| 198 | |
| 199 | #ifdef CONFIG_COMMON_CLK_DISABLE_UNUSED |
| 200 | /* caller must hold prepare_lock */ |
| 201 | static void clk_disable_unused_subtree(struct clk *clk) |
| 202 | { |
| 203 | struct clk *child; |
| 204 | struct hlist_node *tmp; |
| 205 | unsigned long flags; |
| 206 | |
| 207 | if (!clk) |
| 208 | goto out; |
| 209 | |
| 210 | hlist_for_each_entry(child, tmp, &clk->children, child_node) |
| 211 | clk_disable_unused_subtree(child); |
| 212 | |
| 213 | spin_lock_irqsave(&enable_lock, flags); |
| 214 | |
| 215 | if (clk->enable_count) |
| 216 | goto unlock_out; |
| 217 | |
| 218 | if (clk->flags & CLK_IGNORE_UNUSED) |
| 219 | goto unlock_out; |
| 220 | |
| 221 | if (__clk_is_enabled(clk) && clk->ops->disable) |
| 222 | clk->ops->disable(clk->hw); |
| 223 | |
| 224 | unlock_out: |
| 225 | spin_unlock_irqrestore(&enable_lock, flags); |
| 226 | |
| 227 | out: |
| 228 | return; |
| 229 | } |
| 230 | |
| 231 | static int clk_disable_unused(void) |
| 232 | { |
| 233 | struct clk *clk; |
| 234 | struct hlist_node *tmp; |
| 235 | |
| 236 | mutex_lock(&prepare_lock); |
| 237 | |
| 238 | hlist_for_each_entry(clk, tmp, &clk_root_list, child_node) |
| 239 | clk_disable_unused_subtree(clk); |
| 240 | |
| 241 | hlist_for_each_entry(clk, tmp, &clk_orphan_list, child_node) |
| 242 | clk_disable_unused_subtree(clk); |
| 243 | |
| 244 | mutex_unlock(&prepare_lock); |
| 245 | |
| 246 | return 0; |
| 247 | } |
| 248 | late_initcall(clk_disable_unused); |
| 249 | #else |
| 250 | static inline int clk_disable_unused(struct clk *clk) { return 0; } |
| 251 | #endif /* CONFIG_COMMON_CLK_DISABLE_UNUSED */ |
| 252 | |
| 253 | /*** helper functions ***/ |
| 254 | |
| 255 | inline const char *__clk_get_name(struct clk *clk) |
| 256 | { |
| 257 | return !clk ? NULL : clk->name; |
| 258 | } |
| 259 | |
| 260 | inline struct clk_hw *__clk_get_hw(struct clk *clk) |
| 261 | { |
| 262 | return !clk ? NULL : clk->hw; |
| 263 | } |
| 264 | |
| 265 | inline u8 __clk_get_num_parents(struct clk *clk) |
| 266 | { |
| 267 | return !clk ? -EINVAL : clk->num_parents; |
| 268 | } |
| 269 | |
| 270 | inline struct clk *__clk_get_parent(struct clk *clk) |
| 271 | { |
| 272 | return !clk ? NULL : clk->parent; |
| 273 | } |
| 274 | |
| 275 | inline int __clk_get_enable_count(struct clk *clk) |
| 276 | { |
| 277 | return !clk ? -EINVAL : clk->enable_count; |
| 278 | } |
| 279 | |
| 280 | inline int __clk_get_prepare_count(struct clk *clk) |
| 281 | { |
| 282 | return !clk ? -EINVAL : clk->prepare_count; |
| 283 | } |
| 284 | |
| 285 | unsigned long __clk_get_rate(struct clk *clk) |
| 286 | { |
| 287 | unsigned long ret; |
| 288 | |
| 289 | if (!clk) { |
| 290 | ret = -EINVAL; |
| 291 | goto out; |
| 292 | } |
| 293 | |
| 294 | ret = clk->rate; |
| 295 | |
| 296 | if (clk->flags & CLK_IS_ROOT) |
| 297 | goto out; |
| 298 | |
| 299 | if (!clk->parent) |
| 300 | ret = -ENODEV; |
| 301 | |
| 302 | out: |
| 303 | return ret; |
| 304 | } |
| 305 | |
| 306 | inline unsigned long __clk_get_flags(struct clk *clk) |
| 307 | { |
| 308 | return !clk ? -EINVAL : clk->flags; |
| 309 | } |
| 310 | |
| 311 | int __clk_is_enabled(struct clk *clk) |
| 312 | { |
| 313 | int ret; |
| 314 | |
| 315 | if (!clk) |
| 316 | return -EINVAL; |
| 317 | |
| 318 | /* |
| 319 | * .is_enabled is only mandatory for clocks that gate |
| 320 | * fall back to software usage counter if .is_enabled is missing |
| 321 | */ |
| 322 | if (!clk->ops->is_enabled) { |
| 323 | ret = clk->enable_count ? 1 : 0; |
| 324 | goto out; |
| 325 | } |
| 326 | |
| 327 | ret = clk->ops->is_enabled(clk->hw); |
| 328 | out: |
| 329 | return ret; |
| 330 | } |
| 331 | |
| 332 | static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk) |
| 333 | { |
| 334 | struct clk *child; |
| 335 | struct clk *ret; |
| 336 | struct hlist_node *tmp; |
| 337 | |
| 338 | if (!strcmp(clk->name, name)) |
| 339 | return clk; |
| 340 | |
| 341 | hlist_for_each_entry(child, tmp, &clk->children, child_node) { |
| 342 | ret = __clk_lookup_subtree(name, child); |
| 343 | if (ret) |
| 344 | return ret; |
| 345 | } |
| 346 | |
| 347 | return NULL; |
| 348 | } |
| 349 | |
| 350 | struct clk *__clk_lookup(const char *name) |
| 351 | { |
| 352 | struct clk *root_clk; |
| 353 | struct clk *ret; |
| 354 | struct hlist_node *tmp; |
| 355 | |
| 356 | if (!name) |
| 357 | return NULL; |
| 358 | |
| 359 | /* search the 'proper' clk tree first */ |
| 360 | hlist_for_each_entry(root_clk, tmp, &clk_root_list, child_node) { |
| 361 | ret = __clk_lookup_subtree(name, root_clk); |
| 362 | if (ret) |
| 363 | return ret; |
| 364 | } |
| 365 | |
| 366 | /* if not found, then search the orphan tree */ |
| 367 | hlist_for_each_entry(root_clk, tmp, &clk_orphan_list, child_node) { |
| 368 | ret = __clk_lookup_subtree(name, root_clk); |
| 369 | if (ret) |
| 370 | return ret; |
| 371 | } |
| 372 | |
| 373 | return NULL; |
| 374 | } |
| 375 | |
| 376 | /*** clk api ***/ |
| 377 | |
| 378 | void __clk_unprepare(struct clk *clk) |
| 379 | { |
| 380 | if (!clk) |
| 381 | return; |
| 382 | |
| 383 | if (WARN_ON(clk->prepare_count == 0)) |
| 384 | return; |
| 385 | |
| 386 | if (--clk->prepare_count > 0) |
| 387 | return; |
| 388 | |
| 389 | WARN_ON(clk->enable_count > 0); |
| 390 | |
| 391 | if (clk->ops->unprepare) |
| 392 | clk->ops->unprepare(clk->hw); |
| 393 | |
| 394 | __clk_unprepare(clk->parent); |
| 395 | } |
| 396 | |
| 397 | /** |
| 398 | * clk_unprepare - undo preparation of a clock source |
| 399 | * @clk: the clk being unprepare |
| 400 | * |
| 401 | * clk_unprepare may sleep, which differentiates it from clk_disable. In a |
| 402 | * simple case, clk_unprepare can be used instead of clk_disable to gate a clk |
| 403 | * if the operation may sleep. One example is a clk which is accessed over |
| 404 | * I2c. In the complex case a clk gate operation may require a fast and a slow |
| 405 | * part. It is this reason that clk_unprepare and clk_disable are not mutually |
| 406 | * exclusive. In fact clk_disable must be called before clk_unprepare. |
| 407 | */ |
| 408 | void clk_unprepare(struct clk *clk) |
| 409 | { |
| 410 | mutex_lock(&prepare_lock); |
| 411 | __clk_unprepare(clk); |
| 412 | mutex_unlock(&prepare_lock); |
| 413 | } |
| 414 | EXPORT_SYMBOL_GPL(clk_unprepare); |
| 415 | |
| 416 | int __clk_prepare(struct clk *clk) |
| 417 | { |
| 418 | int ret = 0; |
| 419 | |
| 420 | if (!clk) |
| 421 | return 0; |
| 422 | |
| 423 | if (clk->prepare_count == 0) { |
| 424 | ret = __clk_prepare(clk->parent); |
| 425 | if (ret) |
| 426 | return ret; |
| 427 | |
| 428 | if (clk->ops->prepare) { |
| 429 | ret = clk->ops->prepare(clk->hw); |
| 430 | if (ret) { |
| 431 | __clk_unprepare(clk->parent); |
| 432 | return ret; |
| 433 | } |
| 434 | } |
| 435 | } |
| 436 | |
| 437 | clk->prepare_count++; |
| 438 | |
| 439 | return 0; |
| 440 | } |
| 441 | |
| 442 | /** |
| 443 | * clk_prepare - prepare a clock source |
| 444 | * @clk: the clk being prepared |
| 445 | * |
| 446 | * clk_prepare may sleep, which differentiates it from clk_enable. In a simple |
| 447 | * case, clk_prepare can be used instead of clk_enable to ungate a clk if the |
| 448 | * operation may sleep. One example is a clk which is accessed over I2c. In |
| 449 | * the complex case a clk ungate operation may require a fast and a slow part. |
| 450 | * It is this reason that clk_prepare and clk_enable are not mutually |
| 451 | * exclusive. In fact clk_prepare must be called before clk_enable. |
| 452 | * Returns 0 on success, -EERROR otherwise. |
| 453 | */ |
| 454 | int clk_prepare(struct clk *clk) |
| 455 | { |
| 456 | int ret; |
| 457 | |
| 458 | mutex_lock(&prepare_lock); |
| 459 | ret = __clk_prepare(clk); |
| 460 | mutex_unlock(&prepare_lock); |
| 461 | |
| 462 | return ret; |
| 463 | } |
| 464 | EXPORT_SYMBOL_GPL(clk_prepare); |
| 465 | |
| 466 | static void __clk_disable(struct clk *clk) |
| 467 | { |
| 468 | if (!clk) |
| 469 | return; |
| 470 | |
| 471 | if (WARN_ON(clk->enable_count == 0)) |
| 472 | return; |
| 473 | |
| 474 | if (--clk->enable_count > 0) |
| 475 | return; |
| 476 | |
| 477 | if (clk->ops->disable) |
| 478 | clk->ops->disable(clk->hw); |
| 479 | |
| 480 | __clk_disable(clk->parent); |
| 481 | } |
| 482 | |
| 483 | /** |
| 484 | * clk_disable - gate a clock |
| 485 | * @clk: the clk being gated |
| 486 | * |
| 487 | * clk_disable must not sleep, which differentiates it from clk_unprepare. In |
| 488 | * a simple case, clk_disable can be used instead of clk_unprepare to gate a |
| 489 | * clk if the operation is fast and will never sleep. One example is a |
| 490 | * SoC-internal clk which is controlled via simple register writes. In the |
| 491 | * complex case a clk gate operation may require a fast and a slow part. It is |
| 492 | * this reason that clk_unprepare and clk_disable are not mutually exclusive. |
| 493 | * In fact clk_disable must be called before clk_unprepare. |
| 494 | */ |
| 495 | void clk_disable(struct clk *clk) |
| 496 | { |
| 497 | unsigned long flags; |
| 498 | |
| 499 | spin_lock_irqsave(&enable_lock, flags); |
| 500 | __clk_disable(clk); |
| 501 | spin_unlock_irqrestore(&enable_lock, flags); |
| 502 | } |
| 503 | EXPORT_SYMBOL_GPL(clk_disable); |
| 504 | |
| 505 | static int __clk_enable(struct clk *clk) |
| 506 | { |
| 507 | int ret = 0; |
| 508 | |
| 509 | if (!clk) |
| 510 | return 0; |
| 511 | |
| 512 | if (WARN_ON(clk->prepare_count == 0)) |
| 513 | return -ESHUTDOWN; |
| 514 | |
| 515 | if (clk->enable_count == 0) { |
| 516 | ret = __clk_enable(clk->parent); |
| 517 | |
| 518 | if (ret) |
| 519 | return ret; |
| 520 | |
| 521 | if (clk->ops->enable) { |
| 522 | ret = clk->ops->enable(clk->hw); |
| 523 | if (ret) { |
| 524 | __clk_disable(clk->parent); |
| 525 | return ret; |
| 526 | } |
| 527 | } |
| 528 | } |
| 529 | |
| 530 | clk->enable_count++; |
| 531 | return 0; |
| 532 | } |
| 533 | |
| 534 | /** |
| 535 | * clk_enable - ungate a clock |
| 536 | * @clk: the clk being ungated |
| 537 | * |
| 538 | * clk_enable must not sleep, which differentiates it from clk_prepare. In a |
| 539 | * simple case, clk_enable can be used instead of clk_prepare to ungate a clk |
| 540 | * if the operation will never sleep. One example is a SoC-internal clk which |
| 541 | * is controlled via simple register writes. In the complex case a clk ungate |
| 542 | * operation may require a fast and a slow part. It is this reason that |
| 543 | * clk_enable and clk_prepare are not mutually exclusive. In fact clk_prepare |
| 544 | * must be called before clk_enable. Returns 0 on success, -EERROR |
| 545 | * otherwise. |
| 546 | */ |
| 547 | int clk_enable(struct clk *clk) |
| 548 | { |
| 549 | unsigned long flags; |
| 550 | int ret; |
| 551 | |
| 552 | spin_lock_irqsave(&enable_lock, flags); |
| 553 | ret = __clk_enable(clk); |
| 554 | spin_unlock_irqrestore(&enable_lock, flags); |
| 555 | |
| 556 | return ret; |
| 557 | } |
| 558 | EXPORT_SYMBOL_GPL(clk_enable); |
| 559 | |
| 560 | /** |
| 561 | * clk_get_rate - return the rate of clk |
| 562 | * @clk: the clk whose rate is being returned |
| 563 | * |
| 564 | * Simply returns the cached rate of the clk. Does not query the hardware. If |
| 565 | * clk is NULL then returns -EINVAL. |
| 566 | */ |
| 567 | unsigned long clk_get_rate(struct clk *clk) |
| 568 | { |
| 569 | unsigned long rate; |
| 570 | |
| 571 | mutex_lock(&prepare_lock); |
| 572 | rate = __clk_get_rate(clk); |
| 573 | mutex_unlock(&prepare_lock); |
| 574 | |
| 575 | return rate; |
| 576 | } |
| 577 | EXPORT_SYMBOL_GPL(clk_get_rate); |
| 578 | |
| 579 | /** |
| 580 | * __clk_round_rate - round the given rate for a clk |
| 581 | * @clk: round the rate of this clock |
| 582 | * |
| 583 | * Caller must hold prepare_lock. Useful for clk_ops such as .set_rate |
| 584 | */ |
| 585 | unsigned long __clk_round_rate(struct clk *clk, unsigned long rate) |
| 586 | { |
| 587 | unsigned long unused; |
| 588 | |
| 589 | if (!clk) |
| 590 | return -EINVAL; |
| 591 | |
| 592 | if (!clk->ops->round_rate) |
| 593 | return clk->rate; |
| 594 | |
| 595 | if (clk->flags & CLK_SET_RATE_PARENT) |
| 596 | return clk->ops->round_rate(clk->hw, rate, &unused); |
| 597 | else |
| 598 | return clk->ops->round_rate(clk->hw, rate, NULL); |
| 599 | } |
| 600 | |
| 601 | /** |
| 602 | * clk_round_rate - round the given rate for a clk |
| 603 | * @clk: the clk for which we are rounding a rate |
| 604 | * @rate: the rate which is to be rounded |
| 605 | * |
| 606 | * Takes in a rate as input and rounds it to a rate that the clk can actually |
| 607 | * use which is then returned. If clk doesn't support round_rate operation |
| 608 | * then the parent rate is returned. |
| 609 | */ |
| 610 | long clk_round_rate(struct clk *clk, unsigned long rate) |
| 611 | { |
| 612 | unsigned long ret; |
| 613 | |
| 614 | mutex_lock(&prepare_lock); |
| 615 | ret = __clk_round_rate(clk, rate); |
| 616 | mutex_unlock(&prepare_lock); |
| 617 | |
| 618 | return ret; |
| 619 | } |
| 620 | EXPORT_SYMBOL_GPL(clk_round_rate); |
| 621 | |
| 622 | /** |
| 623 | * __clk_notify - call clk notifier chain |
| 624 | * @clk: struct clk * that is changing rate |
| 625 | * @msg: clk notifier type (see include/linux/clk.h) |
| 626 | * @old_rate: old clk rate |
| 627 | * @new_rate: new clk rate |
| 628 | * |
| 629 | * Triggers a notifier call chain on the clk rate-change notification |
| 630 | * for 'clk'. Passes a pointer to the struct clk and the previous |
| 631 | * and current rates to the notifier callback. Intended to be called by |
| 632 | * internal clock code only. Returns NOTIFY_DONE from the last driver |
| 633 | * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if |
| 634 | * a driver returns that. |
| 635 | */ |
| 636 | static int __clk_notify(struct clk *clk, unsigned long msg, |
| 637 | unsigned long old_rate, unsigned long new_rate) |
| 638 | { |
| 639 | struct clk_notifier *cn; |
| 640 | struct clk_notifier_data cnd; |
| 641 | int ret = NOTIFY_DONE; |
| 642 | |
| 643 | cnd.clk = clk; |
| 644 | cnd.old_rate = old_rate; |
| 645 | cnd.new_rate = new_rate; |
| 646 | |
| 647 | list_for_each_entry(cn, &clk_notifier_list, node) { |
| 648 | if (cn->clk == clk) { |
| 649 | ret = srcu_notifier_call_chain(&cn->notifier_head, msg, |
| 650 | &cnd); |
| 651 | break; |
| 652 | } |
| 653 | } |
| 654 | |
| 655 | return ret; |
| 656 | } |
| 657 | |
| 658 | /** |
| 659 | * __clk_recalc_rates |
| 660 | * @clk: first clk in the subtree |
| 661 | * @msg: notification type (see include/linux/clk.h) |
| 662 | * |
| 663 | * Walks the subtree of clks starting with clk and recalculates rates as it |
| 664 | * goes. Note that if a clk does not implement the .recalc_rate callback then |
| 665 | * it is assumed that the clock will take on the rate of it's parent. |
| 666 | * |
| 667 | * clk_recalc_rates also propagates the POST_RATE_CHANGE notification, |
| 668 | * if necessary. |
| 669 | * |
| 670 | * Caller must hold prepare_lock. |
| 671 | */ |
| 672 | static void __clk_recalc_rates(struct clk *clk, unsigned long msg) |
| 673 | { |
| 674 | unsigned long old_rate; |
| 675 | unsigned long parent_rate = 0; |
| 676 | struct hlist_node *tmp; |
| 677 | struct clk *child; |
| 678 | |
| 679 | old_rate = clk->rate; |
| 680 | |
| 681 | if (clk->parent) |
| 682 | parent_rate = clk->parent->rate; |
| 683 | |
| 684 | if (clk->ops->recalc_rate) |
| 685 | clk->rate = clk->ops->recalc_rate(clk->hw, parent_rate); |
| 686 | else |
| 687 | clk->rate = parent_rate; |
| 688 | |
| 689 | /* |
| 690 | * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE |
| 691 | * & ABORT_RATE_CHANGE notifiers |
| 692 | */ |
| 693 | if (clk->notifier_count && msg) |
| 694 | __clk_notify(clk, msg, old_rate, clk->rate); |
| 695 | |
| 696 | hlist_for_each_entry(child, tmp, &clk->children, child_node) |
| 697 | __clk_recalc_rates(child, msg); |
| 698 | } |
| 699 | |
| 700 | /** |
| 701 | * __clk_speculate_rates |
| 702 | * @clk: first clk in the subtree |
| 703 | * @parent_rate: the "future" rate of clk's parent |
| 704 | * |
| 705 | * Walks the subtree of clks starting with clk, speculating rates as it |
| 706 | * goes and firing off PRE_RATE_CHANGE notifications as necessary. |
| 707 | * |
| 708 | * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending |
| 709 | * pre-rate change notifications and returns early if no clks in the |
| 710 | * subtree have subscribed to the notifications. Note that if a clk does not |
| 711 | * implement the .recalc_rate callback then it is assumed that the clock will |
| 712 | * take on the rate of it's parent. |
| 713 | * |
| 714 | * Caller must hold prepare_lock. |
| 715 | */ |
| 716 | static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate) |
| 717 | { |
| 718 | struct hlist_node *tmp; |
| 719 | struct clk *child; |
| 720 | unsigned long new_rate; |
| 721 | int ret = NOTIFY_DONE; |
| 722 | |
| 723 | if (clk->ops->recalc_rate) |
| 724 | new_rate = clk->ops->recalc_rate(clk->hw, parent_rate); |
| 725 | else |
| 726 | new_rate = parent_rate; |
| 727 | |
| 728 | /* abort the rate change if a driver returns NOTIFY_BAD */ |
| 729 | if (clk->notifier_count) |
| 730 | ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate); |
| 731 | |
| 732 | if (ret == NOTIFY_BAD) |
| 733 | goto out; |
| 734 | |
| 735 | hlist_for_each_entry(child, tmp, &clk->children, child_node) { |
| 736 | ret = __clk_speculate_rates(child, new_rate); |
| 737 | if (ret == NOTIFY_BAD) |
| 738 | break; |
| 739 | } |
| 740 | |
| 741 | out: |
| 742 | return ret; |
| 743 | } |
| 744 | |
| 745 | static void clk_calc_subtree(struct clk *clk, unsigned long new_rate) |
| 746 | { |
| 747 | struct clk *child; |
| 748 | struct hlist_node *tmp; |
| 749 | |
| 750 | clk->new_rate = new_rate; |
| 751 | |
| 752 | hlist_for_each_entry(child, tmp, &clk->children, child_node) { |
| 753 | if (child->ops->recalc_rate) |
| 754 | child->new_rate = child->ops->recalc_rate(child->hw, new_rate); |
| 755 | else |
| 756 | child->new_rate = new_rate; |
| 757 | clk_calc_subtree(child, child->new_rate); |
| 758 | } |
| 759 | } |
| 760 | |
| 761 | /* |
| 762 | * calculate the new rates returning the topmost clock that has to be |
| 763 | * changed. |
| 764 | */ |
| 765 | static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate) |
| 766 | { |
| 767 | struct clk *top = clk; |
| 768 | unsigned long best_parent_rate = clk->parent->rate; |
| 769 | unsigned long new_rate; |
| 770 | |
| 771 | if (!clk->ops->round_rate && !(clk->flags & CLK_SET_RATE_PARENT)) { |
| 772 | clk->new_rate = clk->rate; |
| 773 | return NULL; |
| 774 | } |
| 775 | |
| 776 | if (!clk->ops->round_rate && (clk->flags & CLK_SET_RATE_PARENT)) { |
| 777 | top = clk_calc_new_rates(clk->parent, rate); |
| 778 | new_rate = clk->new_rate = clk->parent->new_rate; |
| 779 | |
| 780 | goto out; |
| 781 | } |
| 782 | |
| 783 | if (clk->flags & CLK_SET_RATE_PARENT) |
| 784 | new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate); |
| 785 | else |
| 786 | new_rate = clk->ops->round_rate(clk->hw, rate, NULL); |
| 787 | |
| 788 | if (best_parent_rate != clk->parent->rate) { |
| 789 | top = clk_calc_new_rates(clk->parent, best_parent_rate); |
| 790 | |
| 791 | goto out; |
| 792 | } |
| 793 | |
| 794 | out: |
| 795 | clk_calc_subtree(clk, new_rate); |
| 796 | |
| 797 | return top; |
| 798 | } |
| 799 | |
| 800 | /* |
| 801 | * Notify about rate changes in a subtree. Always walk down the whole tree |
| 802 | * so that in case of an error we can walk down the whole tree again and |
| 803 | * abort the change. |
| 804 | */ |
| 805 | static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event) |
| 806 | { |
| 807 | struct hlist_node *tmp; |
| 808 | struct clk *child, *fail_clk = NULL; |
| 809 | int ret = NOTIFY_DONE; |
| 810 | |
| 811 | if (clk->rate == clk->new_rate) |
| 812 | return 0; |
| 813 | |
| 814 | if (clk->notifier_count) { |
| 815 | ret = __clk_notify(clk, event, clk->rate, clk->new_rate); |
| 816 | if (ret == NOTIFY_BAD) |
| 817 | fail_clk = clk; |
| 818 | } |
| 819 | |
| 820 | hlist_for_each_entry(child, tmp, &clk->children, child_node) { |
| 821 | clk = clk_propagate_rate_change(child, event); |
| 822 | if (clk) |
| 823 | fail_clk = clk; |
| 824 | } |
| 825 | |
| 826 | return fail_clk; |
| 827 | } |
| 828 | |
| 829 | /* |
| 830 | * walk down a subtree and set the new rates notifying the rate |
| 831 | * change on the way |
| 832 | */ |
| 833 | static void clk_change_rate(struct clk *clk) |
| 834 | { |
| 835 | struct clk *child; |
| 836 | unsigned long old_rate; |
| 837 | struct hlist_node *tmp; |
| 838 | |
| 839 | old_rate = clk->rate; |
| 840 | |
| 841 | if (clk->ops->set_rate) |
| 842 | clk->ops->set_rate(clk->hw, clk->new_rate); |
| 843 | |
| 844 | if (clk->ops->recalc_rate) |
| 845 | clk->rate = clk->ops->recalc_rate(clk->hw, |
| 846 | clk->parent->rate); |
| 847 | else |
| 848 | clk->rate = clk->parent->rate; |
| 849 | |
| 850 | if (clk->notifier_count && old_rate != clk->rate) |
| 851 | __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate); |
| 852 | |
| 853 | hlist_for_each_entry(child, tmp, &clk->children, child_node) |
| 854 | clk_change_rate(child); |
| 855 | } |
| 856 | |
| 857 | /** |
| 858 | * clk_set_rate - specify a new rate for clk |
| 859 | * @clk: the clk whose rate is being changed |
| 860 | * @rate: the new rate for clk |
| 861 | * |
Mike Turquette | 5654dc9 | 2012-03-26 11:51:34 -0700 | [diff] [blame^] | 862 | * In the simplest case clk_set_rate will only adjust the rate of clk. |
Mike Turquette | b2476490 | 2012-03-15 23:11:19 -0700 | [diff] [blame] | 863 | * |
Mike Turquette | 5654dc9 | 2012-03-26 11:51:34 -0700 | [diff] [blame^] | 864 | * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to |
| 865 | * propagate up to clk's parent; whether or not this happens depends on the |
| 866 | * outcome of clk's .round_rate implementation. If *parent_rate is unchanged |
| 867 | * after calling .round_rate then upstream parent propagation is ignored. If |
| 868 | * *parent_rate comes back with a new rate for clk's parent then we propagate |
| 869 | * up to clk's parent and set it's rate. Upward propagation will continue |
| 870 | * until either a clk does not support the CLK_SET_RATE_PARENT flag or |
| 871 | * .round_rate stops requesting changes to clk's parent_rate. |
Mike Turquette | b2476490 | 2012-03-15 23:11:19 -0700 | [diff] [blame] | 872 | * |
Mike Turquette | 5654dc9 | 2012-03-26 11:51:34 -0700 | [diff] [blame^] | 873 | * Rate changes are accomplished via tree traversal that also recalculates the |
| 874 | * rates for the clocks and fires off POST_RATE_CHANGE notifiers. |
Mike Turquette | b2476490 | 2012-03-15 23:11:19 -0700 | [diff] [blame] | 875 | * |
| 876 | * Returns 0 on success, -EERROR otherwise. |
| 877 | */ |
| 878 | int clk_set_rate(struct clk *clk, unsigned long rate) |
| 879 | { |
| 880 | struct clk *top, *fail_clk; |
| 881 | int ret = 0; |
| 882 | |
| 883 | /* prevent racing with updates to the clock topology */ |
| 884 | mutex_lock(&prepare_lock); |
| 885 | |
| 886 | /* bail early if nothing to do */ |
| 887 | if (rate == clk->rate) |
| 888 | goto out; |
| 889 | |
| 890 | /* calculate new rates and get the topmost changed clock */ |
| 891 | top = clk_calc_new_rates(clk, rate); |
| 892 | if (!top) { |
| 893 | ret = -EINVAL; |
| 894 | goto out; |
| 895 | } |
| 896 | |
| 897 | /* notify that we are about to change rates */ |
| 898 | fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE); |
| 899 | if (fail_clk) { |
| 900 | pr_warn("%s: failed to set %s rate\n", __func__, |
| 901 | fail_clk->name); |
| 902 | clk_propagate_rate_change(top, ABORT_RATE_CHANGE); |
| 903 | ret = -EBUSY; |
| 904 | goto out; |
| 905 | } |
| 906 | |
| 907 | /* change the rates */ |
| 908 | clk_change_rate(top); |
| 909 | |
| 910 | mutex_unlock(&prepare_lock); |
| 911 | |
| 912 | return 0; |
| 913 | out: |
| 914 | mutex_unlock(&prepare_lock); |
| 915 | |
| 916 | return ret; |
| 917 | } |
| 918 | EXPORT_SYMBOL_GPL(clk_set_rate); |
| 919 | |
| 920 | /** |
| 921 | * clk_get_parent - return the parent of a clk |
| 922 | * @clk: the clk whose parent gets returned |
| 923 | * |
| 924 | * Simply returns clk->parent. Returns NULL if clk is NULL. |
| 925 | */ |
| 926 | struct clk *clk_get_parent(struct clk *clk) |
| 927 | { |
| 928 | struct clk *parent; |
| 929 | |
| 930 | mutex_lock(&prepare_lock); |
| 931 | parent = __clk_get_parent(clk); |
| 932 | mutex_unlock(&prepare_lock); |
| 933 | |
| 934 | return parent; |
| 935 | } |
| 936 | EXPORT_SYMBOL_GPL(clk_get_parent); |
| 937 | |
| 938 | /* |
| 939 | * .get_parent is mandatory for clocks with multiple possible parents. It is |
| 940 | * optional for single-parent clocks. Always call .get_parent if it is |
| 941 | * available and WARN if it is missing for multi-parent clocks. |
| 942 | * |
| 943 | * For single-parent clocks without .get_parent, first check to see if the |
| 944 | * .parents array exists, and if so use it to avoid an expensive tree |
| 945 | * traversal. If .parents does not exist then walk the tree with __clk_lookup. |
| 946 | */ |
| 947 | static struct clk *__clk_init_parent(struct clk *clk) |
| 948 | { |
| 949 | struct clk *ret = NULL; |
| 950 | u8 index; |
| 951 | |
| 952 | /* handle the trivial cases */ |
| 953 | |
| 954 | if (!clk->num_parents) |
| 955 | goto out; |
| 956 | |
| 957 | if (clk->num_parents == 1) { |
| 958 | if (IS_ERR_OR_NULL(clk->parent)) |
| 959 | ret = clk->parent = __clk_lookup(clk->parent_names[0]); |
| 960 | ret = clk->parent; |
| 961 | goto out; |
| 962 | } |
| 963 | |
| 964 | if (!clk->ops->get_parent) { |
| 965 | WARN(!clk->ops->get_parent, |
| 966 | "%s: multi-parent clocks must implement .get_parent\n", |
| 967 | __func__); |
| 968 | goto out; |
| 969 | }; |
| 970 | |
| 971 | /* |
| 972 | * Do our best to cache parent clocks in clk->parents. This prevents |
| 973 | * unnecessary and expensive calls to __clk_lookup. We don't set |
| 974 | * clk->parent here; that is done by the calling function |
| 975 | */ |
| 976 | |
| 977 | index = clk->ops->get_parent(clk->hw); |
| 978 | |
| 979 | if (!clk->parents) |
| 980 | clk->parents = |
| 981 | kmalloc((sizeof(struct clk*) * clk->num_parents), |
| 982 | GFP_KERNEL); |
| 983 | |
| 984 | if (!clk->parents) |
| 985 | ret = __clk_lookup(clk->parent_names[index]); |
| 986 | else if (!clk->parents[index]) |
| 987 | ret = clk->parents[index] = |
| 988 | __clk_lookup(clk->parent_names[index]); |
| 989 | else |
| 990 | ret = clk->parents[index]; |
| 991 | |
| 992 | out: |
| 993 | return ret; |
| 994 | } |
| 995 | |
| 996 | void __clk_reparent(struct clk *clk, struct clk *new_parent) |
| 997 | { |
| 998 | #ifdef CONFIG_COMMON_CLK_DEBUG |
| 999 | struct dentry *d; |
| 1000 | struct dentry *new_parent_d; |
| 1001 | #endif |
| 1002 | |
| 1003 | if (!clk || !new_parent) |
| 1004 | return; |
| 1005 | |
| 1006 | hlist_del(&clk->child_node); |
| 1007 | |
| 1008 | if (new_parent) |
| 1009 | hlist_add_head(&clk->child_node, &new_parent->children); |
| 1010 | else |
| 1011 | hlist_add_head(&clk->child_node, &clk_orphan_list); |
| 1012 | |
| 1013 | #ifdef CONFIG_COMMON_CLK_DEBUG |
| 1014 | if (!inited) |
| 1015 | goto out; |
| 1016 | |
| 1017 | if (new_parent) |
| 1018 | new_parent_d = new_parent->dentry; |
| 1019 | else |
| 1020 | new_parent_d = orphandir; |
| 1021 | |
| 1022 | d = debugfs_rename(clk->dentry->d_parent, clk->dentry, |
| 1023 | new_parent_d, clk->name); |
| 1024 | if (d) |
| 1025 | clk->dentry = d; |
| 1026 | else |
| 1027 | pr_debug("%s: failed to rename debugfs entry for %s\n", |
| 1028 | __func__, clk->name); |
| 1029 | out: |
| 1030 | #endif |
| 1031 | |
| 1032 | clk->parent = new_parent; |
| 1033 | |
| 1034 | __clk_recalc_rates(clk, POST_RATE_CHANGE); |
| 1035 | } |
| 1036 | |
| 1037 | static int __clk_set_parent(struct clk *clk, struct clk *parent) |
| 1038 | { |
| 1039 | struct clk *old_parent; |
| 1040 | unsigned long flags; |
| 1041 | int ret = -EINVAL; |
| 1042 | u8 i; |
| 1043 | |
| 1044 | old_parent = clk->parent; |
| 1045 | |
| 1046 | /* find index of new parent clock using cached parent ptrs */ |
| 1047 | for (i = 0; i < clk->num_parents; i++) |
| 1048 | if (clk->parents[i] == parent) |
| 1049 | break; |
| 1050 | |
| 1051 | /* |
| 1052 | * find index of new parent clock using string name comparison |
| 1053 | * also try to cache the parent to avoid future calls to __clk_lookup |
| 1054 | */ |
| 1055 | if (i == clk->num_parents) |
| 1056 | for (i = 0; i < clk->num_parents; i++) |
| 1057 | if (!strcmp(clk->parent_names[i], parent->name)) { |
| 1058 | clk->parents[i] = __clk_lookup(parent->name); |
| 1059 | break; |
| 1060 | } |
| 1061 | |
| 1062 | if (i == clk->num_parents) { |
| 1063 | pr_debug("%s: clock %s is not a possible parent of clock %s\n", |
| 1064 | __func__, parent->name, clk->name); |
| 1065 | goto out; |
| 1066 | } |
| 1067 | |
| 1068 | /* migrate prepare and enable */ |
| 1069 | if (clk->prepare_count) |
| 1070 | __clk_prepare(parent); |
| 1071 | |
| 1072 | /* FIXME replace with clk_is_enabled(clk) someday */ |
| 1073 | spin_lock_irqsave(&enable_lock, flags); |
| 1074 | if (clk->enable_count) |
| 1075 | __clk_enable(parent); |
| 1076 | spin_unlock_irqrestore(&enable_lock, flags); |
| 1077 | |
| 1078 | /* change clock input source */ |
| 1079 | ret = clk->ops->set_parent(clk->hw, i); |
| 1080 | |
| 1081 | /* clean up old prepare and enable */ |
| 1082 | spin_lock_irqsave(&enable_lock, flags); |
| 1083 | if (clk->enable_count) |
| 1084 | __clk_disable(old_parent); |
| 1085 | spin_unlock_irqrestore(&enable_lock, flags); |
| 1086 | |
| 1087 | if (clk->prepare_count) |
| 1088 | __clk_unprepare(old_parent); |
| 1089 | |
| 1090 | out: |
| 1091 | return ret; |
| 1092 | } |
| 1093 | |
| 1094 | /** |
| 1095 | * clk_set_parent - switch the parent of a mux clk |
| 1096 | * @clk: the mux clk whose input we are switching |
| 1097 | * @parent: the new input to clk |
| 1098 | * |
| 1099 | * Re-parent clk to use parent as it's new input source. If clk has the |
| 1100 | * CLK_SET_PARENT_GATE flag set then clk must be gated for this |
| 1101 | * operation to succeed. After successfully changing clk's parent |
| 1102 | * clk_set_parent will update the clk topology, sysfs topology and |
| 1103 | * propagate rate recalculation via __clk_recalc_rates. Returns 0 on |
| 1104 | * success, -EERROR otherwise. |
| 1105 | */ |
| 1106 | int clk_set_parent(struct clk *clk, struct clk *parent) |
| 1107 | { |
| 1108 | int ret = 0; |
| 1109 | |
| 1110 | if (!clk || !clk->ops) |
| 1111 | return -EINVAL; |
| 1112 | |
| 1113 | if (!clk->ops->set_parent) |
| 1114 | return -ENOSYS; |
| 1115 | |
| 1116 | /* prevent racing with updates to the clock topology */ |
| 1117 | mutex_lock(&prepare_lock); |
| 1118 | |
| 1119 | if (clk->parent == parent) |
| 1120 | goto out; |
| 1121 | |
| 1122 | /* propagate PRE_RATE_CHANGE notifications */ |
| 1123 | if (clk->notifier_count) |
| 1124 | ret = __clk_speculate_rates(clk, parent->rate); |
| 1125 | |
| 1126 | /* abort if a driver objects */ |
| 1127 | if (ret == NOTIFY_STOP) |
| 1128 | goto out; |
| 1129 | |
| 1130 | /* only re-parent if the clock is not in use */ |
| 1131 | if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count) |
| 1132 | ret = -EBUSY; |
| 1133 | else |
| 1134 | ret = __clk_set_parent(clk, parent); |
| 1135 | |
| 1136 | /* propagate ABORT_RATE_CHANGE if .set_parent failed */ |
| 1137 | if (ret) { |
| 1138 | __clk_recalc_rates(clk, ABORT_RATE_CHANGE); |
| 1139 | goto out; |
| 1140 | } |
| 1141 | |
| 1142 | /* propagate rate recalculation downstream */ |
| 1143 | __clk_reparent(clk, parent); |
| 1144 | |
| 1145 | out: |
| 1146 | mutex_unlock(&prepare_lock); |
| 1147 | |
| 1148 | return ret; |
| 1149 | } |
| 1150 | EXPORT_SYMBOL_GPL(clk_set_parent); |
| 1151 | |
| 1152 | /** |
| 1153 | * __clk_init - initialize the data structures in a struct clk |
| 1154 | * @dev: device initializing this clk, placeholder for now |
| 1155 | * @clk: clk being initialized |
| 1156 | * |
| 1157 | * Initializes the lists in struct clk, queries the hardware for the |
| 1158 | * parent and rate and sets them both. |
| 1159 | * |
| 1160 | * Any struct clk passed into __clk_init must have the following members |
| 1161 | * populated: |
| 1162 | * .name |
| 1163 | * .ops |
| 1164 | * .hw |
| 1165 | * .parent_names |
| 1166 | * .num_parents |
| 1167 | * .flags |
| 1168 | * |
| 1169 | * Essentially, everything that would normally be passed into clk_register is |
| 1170 | * assumed to be initialized already in __clk_init. The other members may be |
| 1171 | * populated, but are optional. |
| 1172 | * |
| 1173 | * __clk_init is only exposed via clk-private.h and is intended for use with |
| 1174 | * very large numbers of clocks that need to be statically initialized. It is |
| 1175 | * a layering violation to include clk-private.h from any code which implements |
| 1176 | * a clock's .ops; as such any statically initialized clock data MUST be in a |
| 1177 | * separate C file from the logic that implements it's operations. |
| 1178 | */ |
| 1179 | void __clk_init(struct device *dev, struct clk *clk) |
| 1180 | { |
| 1181 | int i; |
| 1182 | struct clk *orphan; |
| 1183 | struct hlist_node *tmp, *tmp2; |
| 1184 | |
| 1185 | if (!clk) |
| 1186 | return; |
| 1187 | |
| 1188 | mutex_lock(&prepare_lock); |
| 1189 | |
| 1190 | /* check to see if a clock with this name is already registered */ |
| 1191 | if (__clk_lookup(clk->name)) |
| 1192 | goto out; |
| 1193 | |
| 1194 | /* throw a WARN if any entries in parent_names are NULL */ |
| 1195 | for (i = 0; i < clk->num_parents; i++) |
| 1196 | WARN(!clk->parent_names[i], |
| 1197 | "%s: invalid NULL in %s's .parent_names\n", |
| 1198 | __func__, clk->name); |
| 1199 | |
| 1200 | /* |
| 1201 | * Allocate an array of struct clk *'s to avoid unnecessary string |
| 1202 | * look-ups of clk's possible parents. This can fail for clocks passed |
| 1203 | * in to clk_init during early boot; thus any access to clk->parents[] |
| 1204 | * must always check for a NULL pointer and try to populate it if |
| 1205 | * necessary. |
| 1206 | * |
| 1207 | * If clk->parents is not NULL we skip this entire block. This allows |
| 1208 | * for clock drivers to statically initialize clk->parents. |
| 1209 | */ |
| 1210 | if (clk->num_parents && !clk->parents) { |
| 1211 | clk->parents = kmalloc((sizeof(struct clk*) * clk->num_parents), |
| 1212 | GFP_KERNEL); |
| 1213 | /* |
| 1214 | * __clk_lookup returns NULL for parents that have not been |
| 1215 | * clk_init'd; thus any access to clk->parents[] must check |
| 1216 | * for a NULL pointer. We can always perform lazy lookups for |
| 1217 | * missing parents later on. |
| 1218 | */ |
| 1219 | if (clk->parents) |
| 1220 | for (i = 0; i < clk->num_parents; i++) |
| 1221 | clk->parents[i] = |
| 1222 | __clk_lookup(clk->parent_names[i]); |
| 1223 | } |
| 1224 | |
| 1225 | clk->parent = __clk_init_parent(clk); |
| 1226 | |
| 1227 | /* |
| 1228 | * Populate clk->parent if parent has already been __clk_init'd. If |
| 1229 | * parent has not yet been __clk_init'd then place clk in the orphan |
| 1230 | * list. If clk has set the CLK_IS_ROOT flag then place it in the root |
| 1231 | * clk list. |
| 1232 | * |
| 1233 | * Every time a new clk is clk_init'd then we walk the list of orphan |
| 1234 | * clocks and re-parent any that are children of the clock currently |
| 1235 | * being clk_init'd. |
| 1236 | */ |
| 1237 | if (clk->parent) |
| 1238 | hlist_add_head(&clk->child_node, |
| 1239 | &clk->parent->children); |
| 1240 | else if (clk->flags & CLK_IS_ROOT) |
| 1241 | hlist_add_head(&clk->child_node, &clk_root_list); |
| 1242 | else |
| 1243 | hlist_add_head(&clk->child_node, &clk_orphan_list); |
| 1244 | |
| 1245 | /* |
| 1246 | * Set clk's rate. The preferred method is to use .recalc_rate. For |
| 1247 | * simple clocks and lazy developers the default fallback is to use the |
| 1248 | * parent's rate. If a clock doesn't have a parent (or is orphaned) |
| 1249 | * then rate is set to zero. |
| 1250 | */ |
| 1251 | if (clk->ops->recalc_rate) |
| 1252 | clk->rate = clk->ops->recalc_rate(clk->hw, |
| 1253 | __clk_get_rate(clk->parent)); |
| 1254 | else if (clk->parent) |
| 1255 | clk->rate = clk->parent->rate; |
| 1256 | else |
| 1257 | clk->rate = 0; |
| 1258 | |
| 1259 | /* |
| 1260 | * walk the list of orphan clocks and reparent any that are children of |
| 1261 | * this clock |
| 1262 | */ |
| 1263 | hlist_for_each_entry_safe(orphan, tmp, tmp2, &clk_orphan_list, child_node) |
| 1264 | for (i = 0; i < orphan->num_parents; i++) |
| 1265 | if (!strcmp(clk->name, orphan->parent_names[i])) { |
| 1266 | __clk_reparent(orphan, clk); |
| 1267 | break; |
| 1268 | } |
| 1269 | |
| 1270 | /* |
| 1271 | * optional platform-specific magic |
| 1272 | * |
| 1273 | * The .init callback is not used by any of the basic clock types, but |
| 1274 | * exists for weird hardware that must perform initialization magic. |
| 1275 | * Please consider other ways of solving initialization problems before |
| 1276 | * using this callback, as it's use is discouraged. |
| 1277 | */ |
| 1278 | if (clk->ops->init) |
| 1279 | clk->ops->init(clk->hw); |
| 1280 | |
| 1281 | clk_debug_register(clk); |
| 1282 | |
| 1283 | out: |
| 1284 | mutex_unlock(&prepare_lock); |
| 1285 | |
| 1286 | return; |
| 1287 | } |
| 1288 | |
| 1289 | /** |
| 1290 | * clk_register - allocate a new clock, register it and return an opaque cookie |
| 1291 | * @dev: device that is registering this clock |
| 1292 | * @name: clock name |
| 1293 | * @ops: operations this clock supports |
| 1294 | * @hw: link to hardware-specific clock data |
| 1295 | * @parent_names: array of string names for all possible parents |
| 1296 | * @num_parents: number of possible parents |
| 1297 | * @flags: framework-level hints and quirks |
| 1298 | * |
| 1299 | * clk_register is the primary interface for populating the clock tree with new |
| 1300 | * clock nodes. It returns a pointer to the newly allocated struct clk which |
| 1301 | * cannot be dereferenced by driver code but may be used in conjuction with the |
| 1302 | * rest of the clock API. |
| 1303 | */ |
| 1304 | struct clk *clk_register(struct device *dev, const char *name, |
| 1305 | const struct clk_ops *ops, struct clk_hw *hw, |
| 1306 | char **parent_names, u8 num_parents, unsigned long flags) |
| 1307 | { |
| 1308 | struct clk *clk; |
| 1309 | |
| 1310 | clk = kzalloc(sizeof(*clk), GFP_KERNEL); |
| 1311 | if (!clk) |
| 1312 | return NULL; |
| 1313 | |
| 1314 | clk->name = name; |
| 1315 | clk->ops = ops; |
| 1316 | clk->hw = hw; |
| 1317 | clk->flags = flags; |
| 1318 | clk->parent_names = parent_names; |
| 1319 | clk->num_parents = num_parents; |
| 1320 | hw->clk = clk; |
| 1321 | |
| 1322 | __clk_init(dev, clk); |
| 1323 | |
| 1324 | return clk; |
| 1325 | } |
| 1326 | EXPORT_SYMBOL_GPL(clk_register); |
| 1327 | |
| 1328 | /*** clk rate change notifiers ***/ |
| 1329 | |
| 1330 | /** |
| 1331 | * clk_notifier_register - add a clk rate change notifier |
| 1332 | * @clk: struct clk * to watch |
| 1333 | * @nb: struct notifier_block * with callback info |
| 1334 | * |
| 1335 | * Request notification when clk's rate changes. This uses an SRCU |
| 1336 | * notifier because we want it to block and notifier unregistrations are |
| 1337 | * uncommon. The callbacks associated with the notifier must not |
| 1338 | * re-enter into the clk framework by calling any top-level clk APIs; |
| 1339 | * this will cause a nested prepare_lock mutex. |
| 1340 | * |
| 1341 | * Pre-change notifier callbacks will be passed the current, pre-change |
| 1342 | * rate of the clk via struct clk_notifier_data.old_rate. The new, |
| 1343 | * post-change rate of the clk is passed via struct |
| 1344 | * clk_notifier_data.new_rate. |
| 1345 | * |
| 1346 | * Post-change notifiers will pass the now-current, post-change rate of |
| 1347 | * the clk in both struct clk_notifier_data.old_rate and struct |
| 1348 | * clk_notifier_data.new_rate. |
| 1349 | * |
| 1350 | * Abort-change notifiers are effectively the opposite of pre-change |
| 1351 | * notifiers: the original pre-change clk rate is passed in via struct |
| 1352 | * clk_notifier_data.new_rate and the failed post-change rate is passed |
| 1353 | * in via struct clk_notifier_data.old_rate. |
| 1354 | * |
| 1355 | * clk_notifier_register() must be called from non-atomic context. |
| 1356 | * Returns -EINVAL if called with null arguments, -ENOMEM upon |
| 1357 | * allocation failure; otherwise, passes along the return value of |
| 1358 | * srcu_notifier_chain_register(). |
| 1359 | */ |
| 1360 | int clk_notifier_register(struct clk *clk, struct notifier_block *nb) |
| 1361 | { |
| 1362 | struct clk_notifier *cn; |
| 1363 | int ret = -ENOMEM; |
| 1364 | |
| 1365 | if (!clk || !nb) |
| 1366 | return -EINVAL; |
| 1367 | |
| 1368 | mutex_lock(&prepare_lock); |
| 1369 | |
| 1370 | /* search the list of notifiers for this clk */ |
| 1371 | list_for_each_entry(cn, &clk_notifier_list, node) |
| 1372 | if (cn->clk == clk) |
| 1373 | break; |
| 1374 | |
| 1375 | /* if clk wasn't in the notifier list, allocate new clk_notifier */ |
| 1376 | if (cn->clk != clk) { |
| 1377 | cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL); |
| 1378 | if (!cn) |
| 1379 | goto out; |
| 1380 | |
| 1381 | cn->clk = clk; |
| 1382 | srcu_init_notifier_head(&cn->notifier_head); |
| 1383 | |
| 1384 | list_add(&cn->node, &clk_notifier_list); |
| 1385 | } |
| 1386 | |
| 1387 | ret = srcu_notifier_chain_register(&cn->notifier_head, nb); |
| 1388 | |
| 1389 | clk->notifier_count++; |
| 1390 | |
| 1391 | out: |
| 1392 | mutex_unlock(&prepare_lock); |
| 1393 | |
| 1394 | return ret; |
| 1395 | } |
| 1396 | EXPORT_SYMBOL_GPL(clk_notifier_register); |
| 1397 | |
| 1398 | /** |
| 1399 | * clk_notifier_unregister - remove a clk rate change notifier |
| 1400 | * @clk: struct clk * |
| 1401 | * @nb: struct notifier_block * with callback info |
| 1402 | * |
| 1403 | * Request no further notification for changes to 'clk' and frees memory |
| 1404 | * allocated in clk_notifier_register. |
| 1405 | * |
| 1406 | * Returns -EINVAL if called with null arguments; otherwise, passes |
| 1407 | * along the return value of srcu_notifier_chain_unregister(). |
| 1408 | */ |
| 1409 | int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb) |
| 1410 | { |
| 1411 | struct clk_notifier *cn = NULL; |
| 1412 | int ret = -EINVAL; |
| 1413 | |
| 1414 | if (!clk || !nb) |
| 1415 | return -EINVAL; |
| 1416 | |
| 1417 | mutex_lock(&prepare_lock); |
| 1418 | |
| 1419 | list_for_each_entry(cn, &clk_notifier_list, node) |
| 1420 | if (cn->clk == clk) |
| 1421 | break; |
| 1422 | |
| 1423 | if (cn->clk == clk) { |
| 1424 | ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb); |
| 1425 | |
| 1426 | clk->notifier_count--; |
| 1427 | |
| 1428 | /* XXX the notifier code should handle this better */ |
| 1429 | if (!cn->notifier_head.head) { |
| 1430 | srcu_cleanup_notifier_head(&cn->notifier_head); |
| 1431 | kfree(cn); |
| 1432 | } |
| 1433 | |
| 1434 | } else { |
| 1435 | ret = -ENOENT; |
| 1436 | } |
| 1437 | |
| 1438 | mutex_unlock(&prepare_lock); |
| 1439 | |
| 1440 | return ret; |
| 1441 | } |
| 1442 | EXPORT_SYMBOL_GPL(clk_notifier_unregister); |