1 /* 2 * SuperH clock framework 3 * 4 * Copyright (C) 2005 - 2010 Paul Mundt 5 * 6 * This clock framework is derived from the OMAP version by: 7 * 8 * Copyright (C) 2004 - 2008 Nokia Corporation 9 * Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com> 10 * 11 * Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com> 12 * 13 * This file is subject to the terms and conditions of the GNU General Public 14 * License. See the file "COPYING" in the main directory of this archive 15 * for more details. 16 */ 17 #define pr_fmt(fmt) "clock: " fmt 18 19 #include <linux/kernel.h> 20 #include <linux/init.h> 21 #include <linux/module.h> 22 #include <linux/mutex.h> 23 #include <linux/list.h> 24 #include <linux/syscore_ops.h> 25 #include <linux/seq_file.h> 26 #include <linux/err.h> 27 #include <linux/io.h> 28 #include <linux/cpufreq.h> 29 #include <linux/clk.h> 30 #include <linux/sh_clk.h> 31 32 static LIST_HEAD(clock_list); 33 static DEFINE_SPINLOCK(clock_lock); 34 static DEFINE_MUTEX(clock_list_sem); 35 36 /* clock disable operations are not passed on to hardware during boot */ 37 static int allow_disable; 38 39 void clk_rate_table_build(struct clk *clk, 40 struct cpufreq_frequency_table *freq_table, 41 int nr_freqs, 42 struct clk_div_mult_table *src_table, 43 unsigned long *bitmap) 44 { 45 unsigned long mult, div; 46 unsigned long freq; 47 int i; 48 49 clk->nr_freqs = nr_freqs; 50 51 for (i = 0; i < nr_freqs; i++) { 52 div = 1; 53 mult = 1; 54 55 if (src_table->divisors && i < src_table->nr_divisors) 56 div = src_table->divisors[i]; 57 58 if (src_table->multipliers && i < src_table->nr_multipliers) 59 mult = src_table->multipliers[i]; 60 61 if (!div || !mult || (bitmap && !test_bit(i, bitmap))) 62 freq = CPUFREQ_ENTRY_INVALID; 63 else 64 freq = clk->parent->rate * mult / div; 65 66 freq_table[i].driver_data = i; 67 freq_table[i].frequency = freq; 68 } 69 70 /* Termination entry */ 71 freq_table[i].driver_data = i; 72 freq_table[i].frequency = CPUFREQ_TABLE_END; 73 } 74 75 struct clk_rate_round_data; 76 77 struct clk_rate_round_data { 78 unsigned long rate; 79 unsigned int min, max; 80 long (*func)(unsigned int, struct clk_rate_round_data *); 81 void *arg; 82 }; 83 84 #define for_each_frequency(pos, r, freq) \ 85 for (pos = r->min, freq = r->func(pos, r); \ 86 pos <= r->max; pos++, freq = r->func(pos, r)) \ 87 if (unlikely(freq == 0)) \ 88 ; \ 89 else 90 91 static long clk_rate_round_helper(struct clk_rate_round_data *rounder) 92 { 93 unsigned long rate_error, rate_error_prev = ~0UL; 94 unsigned long highest, lowest, freq; 95 long rate_best_fit = -ENOENT; 96 int i; 97 98 highest = 0; 99 lowest = ~0UL; 100 101 for_each_frequency(i, rounder, freq) { 102 if (freq > highest) 103 highest = freq; 104 if (freq < lowest) 105 lowest = freq; 106 107 rate_error = abs(freq - rounder->rate); 108 if (rate_error < rate_error_prev) { 109 rate_best_fit = freq; 110 rate_error_prev = rate_error; 111 } 112 113 if (rate_error == 0) 114 break; 115 } 116 117 if (rounder->rate >= highest) 118 rate_best_fit = highest; 119 if (rounder->rate <= lowest) 120 rate_best_fit = lowest; 121 122 return rate_best_fit; 123 } 124 125 static long clk_rate_table_iter(unsigned int pos, 126 struct clk_rate_round_data *rounder) 127 { 128 struct cpufreq_frequency_table *freq_table = rounder->arg; 129 unsigned long freq = freq_table[pos].frequency; 130 131 if (freq == CPUFREQ_ENTRY_INVALID) 132 freq = 0; 133 134 return freq; 135 } 136 137 long clk_rate_table_round(struct clk *clk, 138 struct cpufreq_frequency_table *freq_table, 139 unsigned long rate) 140 { 141 struct clk_rate_round_data table_round = { 142 .min = 0, 143 .max = clk->nr_freqs - 1, 144 .func = clk_rate_table_iter, 145 .arg = freq_table, 146 .rate = rate, 147 }; 148 149 if (clk->nr_freqs < 1) 150 return -ENOSYS; 151 152 return clk_rate_round_helper(&table_round); 153 } 154 155 static long clk_rate_div_range_iter(unsigned int pos, 156 struct clk_rate_round_data *rounder) 157 { 158 return clk_get_rate(rounder->arg) / pos; 159 } 160 161 long clk_rate_div_range_round(struct clk *clk, unsigned int div_min, 162 unsigned int div_max, unsigned long rate) 163 { 164 struct clk_rate_round_data div_range_round = { 165 .min = div_min, 166 .max = div_max, 167 .func = clk_rate_div_range_iter, 168 .arg = clk_get_parent(clk), 169 .rate = rate, 170 }; 171 172 return clk_rate_round_helper(&div_range_round); 173 } 174 175 static long clk_rate_mult_range_iter(unsigned int pos, 176 struct clk_rate_round_data *rounder) 177 { 178 return clk_get_rate(rounder->arg) * pos; 179 } 180 181 long clk_rate_mult_range_round(struct clk *clk, unsigned int mult_min, 182 unsigned int mult_max, unsigned long rate) 183 { 184 struct clk_rate_round_data mult_range_round = { 185 .min = mult_min, 186 .max = mult_max, 187 .func = clk_rate_mult_range_iter, 188 .arg = clk_get_parent(clk), 189 .rate = rate, 190 }; 191 192 return clk_rate_round_helper(&mult_range_round); 193 } 194 195 int clk_rate_table_find(struct clk *clk, 196 struct cpufreq_frequency_table *freq_table, 197 unsigned long rate) 198 { 199 struct cpufreq_frequency_table *pos; 200 int idx; 201 202 cpufreq_for_each_valid_entry_idx(pos, freq_table, idx) 203 if (pos->frequency == rate) 204 return idx; 205 206 return -ENOENT; 207 } 208 209 /* Used for clocks that always have same value as the parent clock */ 210 unsigned long followparent_recalc(struct clk *clk) 211 { 212 return clk->parent ? clk->parent->rate : 0; 213 } 214 215 int clk_reparent(struct clk *child, struct clk *parent) 216 { 217 list_del_init(&child->sibling); 218 if (parent) 219 list_add(&child->sibling, &parent->children); 220 child->parent = parent; 221 222 return 0; 223 } 224 225 /* Propagate rate to children */ 226 void propagate_rate(struct clk *tclk) 227 { 228 struct clk *clkp; 229 230 list_for_each_entry(clkp, &tclk->children, sibling) { 231 if (clkp->ops && clkp->ops->recalc) 232 clkp->rate = clkp->ops->recalc(clkp); 233 234 propagate_rate(clkp); 235 } 236 } 237 238 static void __clk_disable(struct clk *clk) 239 { 240 if (WARN(!clk->usecount, "Trying to disable clock %p with 0 usecount\n", 241 clk)) 242 return; 243 244 if (!(--clk->usecount)) { 245 if (likely(allow_disable && clk->ops && clk->ops->disable)) 246 clk->ops->disable(clk); 247 if (likely(clk->parent)) 248 __clk_disable(clk->parent); 249 } 250 } 251 252 void clk_disable(struct clk *clk) 253 { 254 unsigned long flags; 255 256 if (!clk) 257 return; 258 259 spin_lock_irqsave(&clock_lock, flags); 260 __clk_disable(clk); 261 spin_unlock_irqrestore(&clock_lock, flags); 262 } 263 EXPORT_SYMBOL_GPL(clk_disable); 264 265 static int __clk_enable(struct clk *clk) 266 { 267 int ret = 0; 268 269 if (clk->usecount++ == 0) { 270 if (clk->parent) { 271 ret = __clk_enable(clk->parent); 272 if (unlikely(ret)) 273 goto err; 274 } 275 276 if (clk->ops && clk->ops->enable) { 277 ret = clk->ops->enable(clk); 278 if (ret) { 279 if (clk->parent) 280 __clk_disable(clk->parent); 281 goto err; 282 } 283 } 284 } 285 286 return ret; 287 err: 288 clk->usecount--; 289 return ret; 290 } 291 292 int clk_enable(struct clk *clk) 293 { 294 unsigned long flags; 295 int ret; 296 297 if (!clk) 298 return 0; 299 300 spin_lock_irqsave(&clock_lock, flags); 301 ret = __clk_enable(clk); 302 spin_unlock_irqrestore(&clock_lock, flags); 303 304 return ret; 305 } 306 EXPORT_SYMBOL_GPL(clk_enable); 307 308 static LIST_HEAD(root_clks); 309 310 /** 311 * recalculate_root_clocks - recalculate and propagate all root clocks 312 * 313 * Recalculates all root clocks (clocks with no parent), which if the 314 * clock's .recalc is set correctly, should also propagate their rates. 315 * Called at init. 316 */ 317 void recalculate_root_clocks(void) 318 { 319 struct clk *clkp; 320 321 list_for_each_entry(clkp, &root_clks, sibling) { 322 if (clkp->ops && clkp->ops->recalc) 323 clkp->rate = clkp->ops->recalc(clkp); 324 propagate_rate(clkp); 325 } 326 } 327 328 static struct clk_mapping dummy_mapping; 329 330 static struct clk *lookup_root_clock(struct clk *clk) 331 { 332 while (clk->parent) 333 clk = clk->parent; 334 335 return clk; 336 } 337 338 static int clk_establish_mapping(struct clk *clk) 339 { 340 struct clk_mapping *mapping = clk->mapping; 341 342 /* 343 * Propagate mappings. 344 */ 345 if (!mapping) { 346 struct clk *clkp; 347 348 /* 349 * dummy mapping for root clocks with no specified ranges 350 */ 351 if (!clk->parent) { 352 clk->mapping = &dummy_mapping; 353 goto out; 354 } 355 356 /* 357 * If we're on a child clock and it provides no mapping of its 358 * own, inherit the mapping from its root clock. 359 */ 360 clkp = lookup_root_clock(clk); 361 mapping = clkp->mapping; 362 BUG_ON(!mapping); 363 } 364 365 /* 366 * Establish initial mapping. 367 */ 368 if (!mapping->base && mapping->phys) { 369 kref_init(&mapping->ref); 370 371 mapping->base = ioremap(mapping->phys, mapping->len); 372 if (unlikely(!mapping->base)) 373 return -ENXIO; 374 } else if (mapping->base) { 375 /* 376 * Bump the refcount for an existing mapping 377 */ 378 kref_get(&mapping->ref); 379 } 380 381 clk->mapping = mapping; 382 out: 383 clk->mapped_reg = clk->mapping->base; 384 clk->mapped_reg += (phys_addr_t)clk->enable_reg - clk->mapping->phys; 385 return 0; 386 } 387 388 static void clk_destroy_mapping(struct kref *kref) 389 { 390 struct clk_mapping *mapping; 391 392 mapping = container_of(kref, struct clk_mapping, ref); 393 394 iounmap(mapping->base); 395 } 396 397 static void clk_teardown_mapping(struct clk *clk) 398 { 399 struct clk_mapping *mapping = clk->mapping; 400 401 /* Nothing to do */ 402 if (mapping == &dummy_mapping) 403 goto out; 404 405 kref_put(&mapping->ref, clk_destroy_mapping); 406 clk->mapping = NULL; 407 out: 408 clk->mapped_reg = NULL; 409 } 410 411 int clk_register(struct clk *clk) 412 { 413 int ret; 414 415 if (IS_ERR_OR_NULL(clk)) 416 return -EINVAL; 417 418 /* 419 * trap out already registered clocks 420 */ 421 if (clk->node.next || clk->node.prev) 422 return 0; 423 424 mutex_lock(&clock_list_sem); 425 426 INIT_LIST_HEAD(&clk->children); 427 clk->usecount = 0; 428 429 ret = clk_establish_mapping(clk); 430 if (unlikely(ret)) 431 goto out_unlock; 432 433 if (clk->parent) 434 list_add(&clk->sibling, &clk->parent->children); 435 else 436 list_add(&clk->sibling, &root_clks); 437 438 list_add(&clk->node, &clock_list); 439 440 #ifdef CONFIG_SH_CLK_CPG_LEGACY 441 if (clk->ops && clk->ops->init) 442 clk->ops->init(clk); 443 #endif 444 445 out_unlock: 446 mutex_unlock(&clock_list_sem); 447 448 return ret; 449 } 450 EXPORT_SYMBOL_GPL(clk_register); 451 452 void clk_unregister(struct clk *clk) 453 { 454 mutex_lock(&clock_list_sem); 455 list_del(&clk->sibling); 456 list_del(&clk->node); 457 clk_teardown_mapping(clk); 458 mutex_unlock(&clock_list_sem); 459 } 460 EXPORT_SYMBOL_GPL(clk_unregister); 461 462 void clk_enable_init_clocks(void) 463 { 464 struct clk *clkp; 465 466 list_for_each_entry(clkp, &clock_list, node) 467 if (clkp->flags & CLK_ENABLE_ON_INIT) 468 clk_enable(clkp); 469 } 470 471 unsigned long clk_get_rate(struct clk *clk) 472 { 473 if (!clk) 474 return 0; 475 476 return clk->rate; 477 } 478 EXPORT_SYMBOL_GPL(clk_get_rate); 479 480 int clk_set_rate(struct clk *clk, unsigned long rate) 481 { 482 int ret = -EOPNOTSUPP; 483 unsigned long flags; 484 485 if (!clk) 486 return 0; 487 488 spin_lock_irqsave(&clock_lock, flags); 489 490 if (likely(clk->ops && clk->ops->set_rate)) { 491 ret = clk->ops->set_rate(clk, rate); 492 if (ret != 0) 493 goto out_unlock; 494 } else { 495 clk->rate = rate; 496 ret = 0; 497 } 498 499 if (clk->ops && clk->ops->recalc) 500 clk->rate = clk->ops->recalc(clk); 501 502 propagate_rate(clk); 503 504 out_unlock: 505 spin_unlock_irqrestore(&clock_lock, flags); 506 507 return ret; 508 } 509 EXPORT_SYMBOL_GPL(clk_set_rate); 510 511 int clk_set_parent(struct clk *clk, struct clk *parent) 512 { 513 unsigned long flags; 514 int ret = -EINVAL; 515 516 if (!parent || !clk) 517 return ret; 518 if (clk->parent == parent) 519 return 0; 520 521 spin_lock_irqsave(&clock_lock, flags); 522 if (clk->usecount == 0) { 523 if (clk->ops->set_parent) 524 ret = clk->ops->set_parent(clk, parent); 525 else 526 ret = clk_reparent(clk, parent); 527 528 if (ret == 0) { 529 if (clk->ops->recalc) 530 clk->rate = clk->ops->recalc(clk); 531 pr_debug("set parent of %p to %p (new rate %ld)\n", 532 clk, clk->parent, clk->rate); 533 propagate_rate(clk); 534 } 535 } else 536 ret = -EBUSY; 537 spin_unlock_irqrestore(&clock_lock, flags); 538 539 return ret; 540 } 541 EXPORT_SYMBOL_GPL(clk_set_parent); 542 543 struct clk *clk_get_parent(struct clk *clk) 544 { 545 if (!clk) 546 return NULL; 547 548 return clk->parent; 549 } 550 EXPORT_SYMBOL_GPL(clk_get_parent); 551 552 long clk_round_rate(struct clk *clk, unsigned long rate) 553 { 554 if (!clk) 555 return 0; 556 557 if (likely(clk->ops && clk->ops->round_rate)) { 558 unsigned long flags, rounded; 559 560 spin_lock_irqsave(&clock_lock, flags); 561 rounded = clk->ops->round_rate(clk, rate); 562 spin_unlock_irqrestore(&clock_lock, flags); 563 564 return rounded; 565 } 566 567 return clk_get_rate(clk); 568 } 569 EXPORT_SYMBOL_GPL(clk_round_rate); 570 571 #ifdef CONFIG_PM 572 static void clks_core_resume(void) 573 { 574 struct clk *clkp; 575 576 list_for_each_entry(clkp, &clock_list, node) { 577 if (likely(clkp->usecount && clkp->ops)) { 578 unsigned long rate = clkp->rate; 579 580 if (likely(clkp->ops->set_parent)) 581 clkp->ops->set_parent(clkp, 582 clkp->parent); 583 if (likely(clkp->ops->set_rate)) 584 clkp->ops->set_rate(clkp, rate); 585 else if (likely(clkp->ops->recalc)) 586 clkp->rate = clkp->ops->recalc(clkp); 587 } 588 } 589 } 590 591 static struct syscore_ops clks_syscore_ops = { 592 .resume = clks_core_resume, 593 }; 594 595 static int __init clk_syscore_init(void) 596 { 597 register_syscore_ops(&clks_syscore_ops); 598 599 return 0; 600 } 601 subsys_initcall(clk_syscore_init); 602 #endif 603 604 static int __init clk_late_init(void) 605 { 606 unsigned long flags; 607 struct clk *clk; 608 609 /* disable all clocks with zero use count */ 610 mutex_lock(&clock_list_sem); 611 spin_lock_irqsave(&clock_lock, flags); 612 613 list_for_each_entry(clk, &clock_list, node) 614 if (!clk->usecount && clk->ops && clk->ops->disable) 615 clk->ops->disable(clk); 616 617 /* from now on allow clock disable operations */ 618 allow_disable = 1; 619 620 spin_unlock_irqrestore(&clock_lock, flags); 621 mutex_unlock(&clock_list_sem); 622 return 0; 623 } 624 late_initcall(clk_late_init); 625