1 /* 2 * linux/arch/arm/mach-omap2/clock.c 3 * 4 * Copyright (C) 2005-2008 Texas Instruments, Inc. 5 * Copyright (C) 2004-2008 Nokia Corporation 6 * 7 * Contacts: 8 * Richard Woodruff <r-woodruff2@ti.com> 9 * Paul Walmsley 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License version 2 as 13 * published by the Free Software Foundation. 14 */ 15 #undef DEBUG 16 17 #include <linux/module.h> 18 #include <linux/kernel.h> 19 #include <linux/device.h> 20 #include <linux/list.h> 21 #include <linux/errno.h> 22 #include <linux/delay.h> 23 #include <linux/clk.h> 24 #include <linux/io.h> 25 #include <linux/bitops.h> 26 27 #include <mach/clock.h> 28 #include <mach/clockdomain.h> 29 #include <mach/cpu.h> 30 #include <asm/div64.h> 31 32 #include <mach/sdrc.h> 33 #include "sdrc.h" 34 #include "clock.h" 35 #include "prm.h" 36 #include "prm-regbits-24xx.h" 37 #include "cm.h" 38 #include "cm-regbits-24xx.h" 39 #include "cm-regbits-34xx.h" 40 41 #define MAX_CLOCK_ENABLE_WAIT 100000 42 43 /* DPLL rate rounding: minimum DPLL multiplier, divider values */ 44 #define DPLL_MIN_MULTIPLIER 1 45 #define DPLL_MIN_DIVIDER 1 46 47 /* Possible error results from _dpll_test_mult */ 48 #define DPLL_MULT_UNDERFLOW -1 49 50 /* 51 * Scale factor to mitigate roundoff errors in DPLL rate rounding. 52 * The higher the scale factor, the greater the risk of arithmetic overflow, 53 * but the closer the rounded rate to the target rate. DPLL_SCALE_FACTOR 54 * must be a power of DPLL_SCALE_BASE. 55 */ 56 #define DPLL_SCALE_FACTOR 64 57 #define DPLL_SCALE_BASE 2 58 #define DPLL_ROUNDING_VAL ((DPLL_SCALE_BASE / 2) * \ 59 (DPLL_SCALE_FACTOR / DPLL_SCALE_BASE)) 60 61 /* DPLL valid Fint frequency band limits - from 34xx TRM Section 4.7.6.2 */ 62 #define DPLL_FINT_BAND1_MIN 750000 63 #define DPLL_FINT_BAND1_MAX 2100000 64 #define DPLL_FINT_BAND2_MIN 7500000 65 #define DPLL_FINT_BAND2_MAX 21000000 66 67 /* _dpll_test_fint() return codes */ 68 #define DPLL_FINT_UNDERFLOW -1 69 #define DPLL_FINT_INVALID -2 70 71 u8 cpu_mask; 72 73 /*------------------------------------------------------------------------- 74 * OMAP2/3 specific clock functions 75 *-------------------------------------------------------------------------*/ 76 77 /* 78 * _dpll_test_fint - test whether an Fint value is valid for the DPLL 79 * @clk: DPLL struct clk to test 80 * @n: divider value (N) to test 81 * 82 * Tests whether a particular divider @n will result in a valid DPLL 83 * internal clock frequency Fint. See the 34xx TRM 4.7.6.2 "DPLL Jitter 84 * Correction". Returns 0 if OK, -1 if the enclosing loop can terminate 85 * (assuming that it is counting N upwards), or -2 if the enclosing loop 86 * should skip to the next iteration (again assuming N is increasing). 87 */ 88 static int _dpll_test_fint(struct clk *clk, u8 n) 89 { 90 struct dpll_data *dd; 91 long fint; 92 int ret = 0; 93 94 dd = clk->dpll_data; 95 96 /* DPLL divider must result in a valid jitter correction val */ 97 fint = clk->parent->rate / (n + 1); 98 if (fint < DPLL_FINT_BAND1_MIN) { 99 100 pr_debug("rejecting n=%d due to Fint failure, " 101 "lowering max_divider\n", n); 102 dd->max_divider = n; 103 ret = DPLL_FINT_UNDERFLOW; 104 105 } else if (fint > DPLL_FINT_BAND1_MAX && 106 fint < DPLL_FINT_BAND2_MIN) { 107 108 pr_debug("rejecting n=%d due to Fint failure\n", n); 109 ret = DPLL_FINT_INVALID; 110 111 } else if (fint > DPLL_FINT_BAND2_MAX) { 112 113 pr_debug("rejecting n=%d due to Fint failure, " 114 "boosting min_divider\n", n); 115 dd->min_divider = n; 116 ret = DPLL_FINT_INVALID; 117 118 } 119 120 return ret; 121 } 122 123 /** 124 * omap2_init_clk_clkdm - look up a clockdomain name, store pointer in clk 125 * @clk: OMAP clock struct ptr to use 126 * 127 * Convert a clockdomain name stored in a struct clk 'clk' into a 128 * clockdomain pointer, and save it into the struct clk. Intended to be 129 * called during clk_register(). No return value. 130 */ 131 void omap2_init_clk_clkdm(struct clk *clk) 132 { 133 struct clockdomain *clkdm; 134 135 if (!clk->clkdm_name) 136 return; 137 138 clkdm = clkdm_lookup(clk->clkdm_name); 139 if (clkdm) { 140 pr_debug("clock: associated clk %s to clkdm %s\n", 141 clk->name, clk->clkdm_name); 142 clk->clkdm = clkdm; 143 } else { 144 pr_debug("clock: could not associate clk %s to " 145 "clkdm %s\n", clk->name, clk->clkdm_name); 146 } 147 } 148 149 /** 150 * omap2_init_clksel_parent - set a clksel clk's parent field from the hardware 151 * @clk: OMAP clock struct ptr to use 152 * 153 * Given a pointer to a source-selectable struct clk, read the hardware 154 * register and determine what its parent is currently set to. Update the 155 * clk->parent field with the appropriate clk ptr. 156 */ 157 void omap2_init_clksel_parent(struct clk *clk) 158 { 159 const struct clksel *clks; 160 const struct clksel_rate *clkr; 161 u32 r, found = 0; 162 163 if (!clk->clksel) 164 return; 165 166 r = __raw_readl(clk->clksel_reg) & clk->clksel_mask; 167 r >>= __ffs(clk->clksel_mask); 168 169 for (clks = clk->clksel; clks->parent && !found; clks++) { 170 for (clkr = clks->rates; clkr->div && !found; clkr++) { 171 if ((clkr->flags & cpu_mask) && (clkr->val == r)) { 172 if (clk->parent != clks->parent) { 173 pr_debug("clock: inited %s parent " 174 "to %s (was %s)\n", 175 clk->name, clks->parent->name, 176 ((clk->parent) ? 177 clk->parent->name : "NULL")); 178 clk->parent = clks->parent; 179 }; 180 found = 1; 181 } 182 } 183 } 184 185 if (!found) 186 printk(KERN_ERR "clock: init parent: could not find " 187 "regval %0x for clock %s\n", r, clk->name); 188 189 return; 190 } 191 192 /* Returns the DPLL rate */ 193 u32 omap2_get_dpll_rate(struct clk *clk) 194 { 195 long long dpll_clk; 196 u32 dpll_mult, dpll_div, dpll; 197 struct dpll_data *dd; 198 199 dd = clk->dpll_data; 200 /* REVISIT: What do we return on error? */ 201 if (!dd) 202 return 0; 203 204 dpll = __raw_readl(dd->mult_div1_reg); 205 dpll_mult = dpll & dd->mult_mask; 206 dpll_mult >>= __ffs(dd->mult_mask); 207 dpll_div = dpll & dd->div1_mask; 208 dpll_div >>= __ffs(dd->div1_mask); 209 210 dpll_clk = (long long)clk->parent->rate * dpll_mult; 211 do_div(dpll_clk, dpll_div + 1); 212 213 return dpll_clk; 214 } 215 216 /* 217 * Used for clocks that have the same value as the parent clock, 218 * divided by some factor 219 */ 220 void omap2_fixed_divisor_recalc(struct clk *clk) 221 { 222 WARN_ON(!clk->fixed_div); 223 224 clk->rate = clk->parent->rate / clk->fixed_div; 225 } 226 227 /** 228 * omap2_wait_clock_ready - wait for clock to enable 229 * @reg: physical address of clock IDLEST register 230 * @mask: value to mask against to determine if the clock is active 231 * @name: name of the clock (for printk) 232 * 233 * Returns 1 if the clock enabled in time, or 0 if it failed to enable 234 * in roughly MAX_CLOCK_ENABLE_WAIT microseconds. 235 */ 236 int omap2_wait_clock_ready(void __iomem *reg, u32 mask, const char *name) 237 { 238 int i = 0; 239 int ena = 0; 240 241 /* 242 * 24xx uses 0 to indicate not ready, and 1 to indicate ready. 243 * 34xx reverses this, just to keep us on our toes 244 */ 245 if (cpu_mask & (RATE_IN_242X | RATE_IN_243X)) 246 ena = mask; 247 else if (cpu_mask & RATE_IN_343X) 248 ena = 0; 249 250 /* Wait for lock */ 251 while (((__raw_readl(reg) & mask) != ena) && 252 (i++ < MAX_CLOCK_ENABLE_WAIT)) { 253 udelay(1); 254 } 255 256 if (i < MAX_CLOCK_ENABLE_WAIT) 257 pr_debug("Clock %s stable after %d loops\n", name, i); 258 else 259 printk(KERN_ERR "Clock %s didn't enable in %d tries\n", 260 name, MAX_CLOCK_ENABLE_WAIT); 261 262 263 return (i < MAX_CLOCK_ENABLE_WAIT) ? 1 : 0; 264 }; 265 266 267 /* 268 * Note: We don't need special code here for INVERT_ENABLE 269 * for the time being since INVERT_ENABLE only applies to clocks enabled by 270 * CM_CLKEN_PLL 271 */ 272 static void omap2_clk_wait_ready(struct clk *clk) 273 { 274 void __iomem *reg, *other_reg, *st_reg; 275 u32 bit; 276 277 /* 278 * REVISIT: This code is pretty ugly. It would be nice to generalize 279 * it and pull it into struct clk itself somehow. 280 */ 281 reg = clk->enable_reg; 282 283 /* 284 * Convert CM_ICLKEN* <-> CM_FCLKEN*. This conversion assumes 285 * it's just a matter of XORing the bits. 286 */ 287 other_reg = (void __iomem *)((u32)reg ^ (CM_FCLKEN ^ CM_ICLKEN)); 288 289 /* Check if both functional and interface clocks 290 * are running. */ 291 bit = 1 << clk->enable_bit; 292 if (!(__raw_readl(other_reg) & bit)) 293 return; 294 st_reg = (void __iomem *)(((u32)other_reg & ~0xf0) | 0x20); /* CM_IDLEST* */ 295 296 omap2_wait_clock_ready(st_reg, bit, clk->name); 297 } 298 299 static int omap2_dflt_clk_enable(struct clk *clk) 300 { 301 u32 v; 302 303 if (unlikely(clk->enable_reg == NULL)) { 304 printk(KERN_ERR "clock.c: Enable for %s without enable code\n", 305 clk->name); 306 return 0; /* REVISIT: -EINVAL */ 307 } 308 309 v = __raw_readl(clk->enable_reg); 310 if (clk->flags & INVERT_ENABLE) 311 v &= ~(1 << clk->enable_bit); 312 else 313 v |= (1 << clk->enable_bit); 314 __raw_writel(v, clk->enable_reg); 315 wmb(); 316 317 return 0; 318 } 319 320 static int omap2_dflt_clk_enable_wait(struct clk *clk) 321 { 322 int ret; 323 324 if (!clk->enable_reg) { 325 printk(KERN_ERR "clock.c: Enable for %s without enable code\n", 326 clk->name); 327 return 0; /* REVISIT: -EINVAL */ 328 } 329 330 ret = omap2_dflt_clk_enable(clk); 331 if (ret == 0) 332 omap2_clk_wait_ready(clk); 333 return ret; 334 } 335 336 static void omap2_dflt_clk_disable(struct clk *clk) 337 { 338 u32 v; 339 340 if (!clk->enable_reg) { 341 /* 342 * 'Independent' here refers to a clock which is not 343 * controlled by its parent. 344 */ 345 printk(KERN_ERR "clock: clk_disable called on independent " 346 "clock %s which has no enable_reg\n", clk->name); 347 return; 348 } 349 350 v = __raw_readl(clk->enable_reg); 351 if (clk->flags & INVERT_ENABLE) 352 v |= (1 << clk->enable_bit); 353 else 354 v &= ~(1 << clk->enable_bit); 355 __raw_writel(v, clk->enable_reg); 356 wmb(); 357 } 358 359 const struct clkops clkops_omap2_dflt_wait = { 360 .enable = omap2_dflt_clk_enable_wait, 361 .disable = omap2_dflt_clk_disable, 362 }; 363 364 const struct clkops clkops_omap2_dflt = { 365 .enable = omap2_dflt_clk_enable, 366 .disable = omap2_dflt_clk_disable, 367 }; 368 369 /* Enables clock without considering parent dependencies or use count 370 * REVISIT: Maybe change this to use clk->enable like on omap1? 371 */ 372 static int _omap2_clk_enable(struct clk *clk) 373 { 374 return clk->ops->enable(clk); 375 } 376 377 /* Disables clock without considering parent dependencies or use count */ 378 static void _omap2_clk_disable(struct clk *clk) 379 { 380 clk->ops->disable(clk); 381 } 382 383 void omap2_clk_disable(struct clk *clk) 384 { 385 if (clk->usecount > 0 && !(--clk->usecount)) { 386 _omap2_clk_disable(clk); 387 if (clk->parent) 388 omap2_clk_disable(clk->parent); 389 if (clk->clkdm) 390 omap2_clkdm_clk_disable(clk->clkdm, clk); 391 392 } 393 } 394 395 int omap2_clk_enable(struct clk *clk) 396 { 397 int ret = 0; 398 399 if (clk->usecount++ == 0) { 400 if (clk->parent) 401 ret = omap2_clk_enable(clk->parent); 402 403 if (ret != 0) { 404 clk->usecount--; 405 return ret; 406 } 407 408 if (clk->clkdm) 409 omap2_clkdm_clk_enable(clk->clkdm, clk); 410 411 ret = _omap2_clk_enable(clk); 412 413 if (ret != 0) { 414 if (clk->clkdm) 415 omap2_clkdm_clk_disable(clk->clkdm, clk); 416 417 if (clk->parent) { 418 omap2_clk_disable(clk->parent); 419 clk->usecount--; 420 } 421 } 422 } 423 424 return ret; 425 } 426 427 /* 428 * Used for clocks that are part of CLKSEL_xyz governed clocks. 429 * REVISIT: Maybe change to use clk->enable() functions like on omap1? 430 */ 431 void omap2_clksel_recalc(struct clk *clk) 432 { 433 u32 div = 0; 434 435 pr_debug("clock: recalc'ing clksel clk %s\n", clk->name); 436 437 div = omap2_clksel_get_divisor(clk); 438 if (div == 0) 439 return; 440 441 if (clk->rate == (clk->parent->rate / div)) 442 return; 443 clk->rate = clk->parent->rate / div; 444 445 pr_debug("clock: new clock rate is %ld (div %d)\n", clk->rate, div); 446 } 447 448 /** 449 * omap2_get_clksel_by_parent - return clksel struct for a given clk & parent 450 * @clk: OMAP struct clk ptr to inspect 451 * @src_clk: OMAP struct clk ptr of the parent clk to search for 452 * 453 * Scan the struct clksel array associated with the clock to find 454 * the element associated with the supplied parent clock address. 455 * Returns a pointer to the struct clksel on success or NULL on error. 456 */ 457 static const struct clksel *omap2_get_clksel_by_parent(struct clk *clk, 458 struct clk *src_clk) 459 { 460 const struct clksel *clks; 461 462 if (!clk->clksel) 463 return NULL; 464 465 for (clks = clk->clksel; clks->parent; clks++) { 466 if (clks->parent == src_clk) 467 break; /* Found the requested parent */ 468 } 469 470 if (!clks->parent) { 471 printk(KERN_ERR "clock: Could not find parent clock %s in " 472 "clksel array of clock %s\n", src_clk->name, 473 clk->name); 474 return NULL; 475 } 476 477 return clks; 478 } 479 480 /** 481 * omap2_clksel_round_rate_div - find divisor for the given clock and rate 482 * @clk: OMAP struct clk to use 483 * @target_rate: desired clock rate 484 * @new_div: ptr to where we should store the divisor 485 * 486 * Finds 'best' divider value in an array based on the source and target 487 * rates. The divider array must be sorted with smallest divider first. 488 * Note that this will not work for clocks which are part of CONFIG_PARTICIPANT, 489 * they are only settable as part of virtual_prcm set. 490 * 491 * Returns the rounded clock rate or returns 0xffffffff on error. 492 */ 493 u32 omap2_clksel_round_rate_div(struct clk *clk, unsigned long target_rate, 494 u32 *new_div) 495 { 496 unsigned long test_rate; 497 const struct clksel *clks; 498 const struct clksel_rate *clkr; 499 u32 last_div = 0; 500 501 printk(KERN_INFO "clock: clksel_round_rate_div: %s target_rate %ld\n", 502 clk->name, target_rate); 503 504 *new_div = 1; 505 506 clks = omap2_get_clksel_by_parent(clk, clk->parent); 507 if (!clks) 508 return ~0; 509 510 for (clkr = clks->rates; clkr->div; clkr++) { 511 if (!(clkr->flags & cpu_mask)) 512 continue; 513 514 /* Sanity check */ 515 if (clkr->div <= last_div) 516 printk(KERN_ERR "clock: clksel_rate table not sorted " 517 "for clock %s", clk->name); 518 519 last_div = clkr->div; 520 521 test_rate = clk->parent->rate / clkr->div; 522 523 if (test_rate <= target_rate) 524 break; /* found it */ 525 } 526 527 if (!clkr->div) { 528 printk(KERN_ERR "clock: Could not find divisor for target " 529 "rate %ld for clock %s parent %s\n", target_rate, 530 clk->name, clk->parent->name); 531 return ~0; 532 } 533 534 *new_div = clkr->div; 535 536 printk(KERN_INFO "clock: new_div = %d, new_rate = %ld\n", *new_div, 537 (clk->parent->rate / clkr->div)); 538 539 return (clk->parent->rate / clkr->div); 540 } 541 542 /** 543 * omap2_clksel_round_rate - find rounded rate for the given clock and rate 544 * @clk: OMAP struct clk to use 545 * @target_rate: desired clock rate 546 * 547 * Compatibility wrapper for OMAP clock framework 548 * Finds best target rate based on the source clock and possible dividers. 549 * rates. The divider array must be sorted with smallest divider first. 550 * Note that this will not work for clocks which are part of CONFIG_PARTICIPANT, 551 * they are only settable as part of virtual_prcm set. 552 * 553 * Returns the rounded clock rate or returns 0xffffffff on error. 554 */ 555 long omap2_clksel_round_rate(struct clk *clk, unsigned long target_rate) 556 { 557 u32 new_div; 558 559 return omap2_clksel_round_rate_div(clk, target_rate, &new_div); 560 } 561 562 563 /* Given a clock and a rate apply a clock specific rounding function */ 564 long omap2_clk_round_rate(struct clk *clk, unsigned long rate) 565 { 566 if (clk->round_rate) 567 return clk->round_rate(clk, rate); 568 569 if (clk->flags & RATE_FIXED) 570 printk(KERN_ERR "clock: generic omap2_clk_round_rate called " 571 "on fixed-rate clock %s\n", clk->name); 572 573 return clk->rate; 574 } 575 576 /** 577 * omap2_clksel_to_divisor() - turn clksel field value into integer divider 578 * @clk: OMAP struct clk to use 579 * @field_val: register field value to find 580 * 581 * Given a struct clk of a rate-selectable clksel clock, and a register field 582 * value to search for, find the corresponding clock divisor. The register 583 * field value should be pre-masked and shifted down so the LSB is at bit 0 584 * before calling. Returns 0 on error 585 */ 586 u32 omap2_clksel_to_divisor(struct clk *clk, u32 field_val) 587 { 588 const struct clksel *clks; 589 const struct clksel_rate *clkr; 590 591 clks = omap2_get_clksel_by_parent(clk, clk->parent); 592 if (!clks) 593 return 0; 594 595 for (clkr = clks->rates; clkr->div; clkr++) { 596 if ((clkr->flags & cpu_mask) && (clkr->val == field_val)) 597 break; 598 } 599 600 if (!clkr->div) { 601 printk(KERN_ERR "clock: Could not find fieldval %d for " 602 "clock %s parent %s\n", field_val, clk->name, 603 clk->parent->name); 604 return 0; 605 } 606 607 return clkr->div; 608 } 609 610 /** 611 * omap2_divisor_to_clksel() - turn clksel integer divisor into a field value 612 * @clk: OMAP struct clk to use 613 * @div: integer divisor to search for 614 * 615 * Given a struct clk of a rate-selectable clksel clock, and a clock divisor, 616 * find the corresponding register field value. The return register value is 617 * the value before left-shifting. Returns 0xffffffff on error 618 */ 619 u32 omap2_divisor_to_clksel(struct clk *clk, u32 div) 620 { 621 const struct clksel *clks; 622 const struct clksel_rate *clkr; 623 624 /* should never happen */ 625 WARN_ON(div == 0); 626 627 clks = omap2_get_clksel_by_parent(clk, clk->parent); 628 if (!clks) 629 return 0; 630 631 for (clkr = clks->rates; clkr->div; clkr++) { 632 if ((clkr->flags & cpu_mask) && (clkr->div == div)) 633 break; 634 } 635 636 if (!clkr->div) { 637 printk(KERN_ERR "clock: Could not find divisor %d for " 638 "clock %s parent %s\n", div, clk->name, 639 clk->parent->name); 640 return 0; 641 } 642 643 return clkr->val; 644 } 645 646 /** 647 * omap2_clksel_get_divisor - get current divider applied to parent clock. 648 * @clk: OMAP struct clk to use. 649 * 650 * Returns the integer divisor upon success or 0 on error. 651 */ 652 u32 omap2_clksel_get_divisor(struct clk *clk) 653 { 654 u32 v; 655 656 if (!clk->clksel_mask) 657 return 0; 658 659 v = __raw_readl(clk->clksel_reg) & clk->clksel_mask; 660 v >>= __ffs(clk->clksel_mask); 661 662 return omap2_clksel_to_divisor(clk, v); 663 } 664 665 int omap2_clksel_set_rate(struct clk *clk, unsigned long rate) 666 { 667 u32 v, field_val, validrate, new_div = 0; 668 669 if (!clk->clksel_mask) 670 return -EINVAL; 671 672 validrate = omap2_clksel_round_rate_div(clk, rate, &new_div); 673 if (validrate != rate) 674 return -EINVAL; 675 676 field_val = omap2_divisor_to_clksel(clk, new_div); 677 if (field_val == ~0) 678 return -EINVAL; 679 680 v = __raw_readl(clk->clksel_reg); 681 v &= ~clk->clksel_mask; 682 v |= field_val << __ffs(clk->clksel_mask); 683 __raw_writel(v, clk->clksel_reg); 684 wmb(); 685 686 clk->rate = clk->parent->rate / new_div; 687 688 if (clk->flags & DELAYED_APP && cpu_is_omap24xx()) { 689 prm_write_mod_reg(OMAP24XX_VALID_CONFIG, 690 OMAP24XX_GR_MOD, OMAP24XX_PRCM_CLKCFG_CTRL_OFFSET); 691 wmb(); 692 } 693 694 return 0; 695 } 696 697 698 /* Set the clock rate for a clock source */ 699 int omap2_clk_set_rate(struct clk *clk, unsigned long rate) 700 { 701 int ret = -EINVAL; 702 703 pr_debug("clock: set_rate for clock %s to rate %ld\n", clk->name, rate); 704 705 /* CONFIG_PARTICIPANT clocks are changed only in sets via the 706 rate table mechanism, driven by mpu_speed */ 707 if (clk->flags & CONFIG_PARTICIPANT) 708 return -EINVAL; 709 710 /* dpll_ck, core_ck, virt_prcm_set; plus all clksel clocks */ 711 if (clk->set_rate) 712 ret = clk->set_rate(clk, rate); 713 714 return ret; 715 } 716 717 /* 718 * Converts encoded control register address into a full address 719 * On error, the return value (parent_div) will be 0. 720 */ 721 static u32 _omap2_clksel_get_src_field(struct clk *src_clk, struct clk *clk, 722 u32 *field_val) 723 { 724 const struct clksel *clks; 725 const struct clksel_rate *clkr; 726 727 clks = omap2_get_clksel_by_parent(clk, src_clk); 728 if (!clks) 729 return 0; 730 731 for (clkr = clks->rates; clkr->div; clkr++) { 732 if (clkr->flags & (cpu_mask | DEFAULT_RATE)) 733 break; /* Found the default rate for this platform */ 734 } 735 736 if (!clkr->div) { 737 printk(KERN_ERR "clock: Could not find default rate for " 738 "clock %s parent %s\n", clk->name, 739 src_clk->parent->name); 740 return 0; 741 } 742 743 /* Should never happen. Add a clksel mask to the struct clk. */ 744 WARN_ON(clk->clksel_mask == 0); 745 746 *field_val = clkr->val; 747 748 return clkr->div; 749 } 750 751 int omap2_clk_set_parent(struct clk *clk, struct clk *new_parent) 752 { 753 u32 field_val, v, parent_div; 754 755 if (clk->flags & CONFIG_PARTICIPANT) 756 return -EINVAL; 757 758 if (!clk->clksel) 759 return -EINVAL; 760 761 parent_div = _omap2_clksel_get_src_field(new_parent, clk, &field_val); 762 if (!parent_div) 763 return -EINVAL; 764 765 if (clk->usecount > 0) 766 _omap2_clk_disable(clk); 767 768 /* Set new source value (previous dividers if any in effect) */ 769 v = __raw_readl(clk->clksel_reg); 770 v &= ~clk->clksel_mask; 771 v |= field_val << __ffs(clk->clksel_mask); 772 __raw_writel(v, clk->clksel_reg); 773 wmb(); 774 775 if (clk->flags & DELAYED_APP && cpu_is_omap24xx()) { 776 __raw_writel(OMAP24XX_VALID_CONFIG, OMAP24XX_PRCM_CLKCFG_CTRL); 777 wmb(); 778 } 779 780 if (clk->usecount > 0) 781 _omap2_clk_enable(clk); 782 783 clk->parent = new_parent; 784 785 /* CLKSEL clocks follow their parents' rates, divided by a divisor */ 786 clk->rate = new_parent->rate; 787 788 if (parent_div > 0) 789 clk->rate /= parent_div; 790 791 pr_debug("clock: set parent of %s to %s (new rate %ld)\n", 792 clk->name, clk->parent->name, clk->rate); 793 794 return 0; 795 } 796 797 /* DPLL rate rounding code */ 798 799 /** 800 * omap2_dpll_set_rate_tolerance: set the error tolerance during rate rounding 801 * @clk: struct clk * of the DPLL 802 * @tolerance: maximum rate error tolerance 803 * 804 * Set the maximum DPLL rate error tolerance for the rate rounding 805 * algorithm. The rate tolerance is an attempt to balance DPLL power 806 * saving (the least divider value "n") vs. rate fidelity (the least 807 * difference between the desired DPLL target rate and the rounded 808 * rate out of the algorithm). So, increasing the tolerance is likely 809 * to decrease DPLL power consumption and increase DPLL rate error. 810 * Returns -EINVAL if provided a null clock ptr or a clk that is not a 811 * DPLL; or 0 upon success. 812 */ 813 int omap2_dpll_set_rate_tolerance(struct clk *clk, unsigned int tolerance) 814 { 815 if (!clk || !clk->dpll_data) 816 return -EINVAL; 817 818 clk->dpll_data->rate_tolerance = tolerance; 819 820 return 0; 821 } 822 823 static unsigned long _dpll_compute_new_rate(unsigned long parent_rate, 824 unsigned int m, unsigned int n) 825 { 826 unsigned long long num; 827 828 num = (unsigned long long)parent_rate * m; 829 do_div(num, n); 830 return num; 831 } 832 833 /* 834 * _dpll_test_mult - test a DPLL multiplier value 835 * @m: pointer to the DPLL m (multiplier) value under test 836 * @n: current DPLL n (divider) value under test 837 * @new_rate: pointer to storage for the resulting rounded rate 838 * @target_rate: the desired DPLL rate 839 * @parent_rate: the DPLL's parent clock rate 840 * 841 * This code tests a DPLL multiplier value, ensuring that the 842 * resulting rate will not be higher than the target_rate, and that 843 * the multiplier value itself is valid for the DPLL. Initially, the 844 * integer pointed to by the m argument should be prescaled by 845 * multiplying by DPLL_SCALE_FACTOR. The code will replace this with 846 * a non-scaled m upon return. This non-scaled m will result in a 847 * new_rate as close as possible to target_rate (but not greater than 848 * target_rate) given the current (parent_rate, n, prescaled m) 849 * triple. Returns DPLL_MULT_UNDERFLOW in the event that the 850 * non-scaled m attempted to underflow, which can allow the calling 851 * function to bail out early; or 0 upon success. 852 */ 853 static int _dpll_test_mult(int *m, int n, unsigned long *new_rate, 854 unsigned long target_rate, 855 unsigned long parent_rate) 856 { 857 int r = 0, carry = 0; 858 859 /* Unscale m and round if necessary */ 860 if (*m % DPLL_SCALE_FACTOR >= DPLL_ROUNDING_VAL) 861 carry = 1; 862 *m = (*m / DPLL_SCALE_FACTOR) + carry; 863 864 /* 865 * The new rate must be <= the target rate to avoid programming 866 * a rate that is impossible for the hardware to handle 867 */ 868 *new_rate = _dpll_compute_new_rate(parent_rate, *m, n); 869 if (*new_rate > target_rate) { 870 (*m)--; 871 *new_rate = 0; 872 } 873 874 /* Guard against m underflow */ 875 if (*m < DPLL_MIN_MULTIPLIER) { 876 *m = DPLL_MIN_MULTIPLIER; 877 *new_rate = 0; 878 r = DPLL_MULT_UNDERFLOW; 879 } 880 881 if (*new_rate == 0) 882 *new_rate = _dpll_compute_new_rate(parent_rate, *m, n); 883 884 return r; 885 } 886 887 /** 888 * omap2_dpll_round_rate - round a target rate for an OMAP DPLL 889 * @clk: struct clk * for a DPLL 890 * @target_rate: desired DPLL clock rate 891 * 892 * Given a DPLL, a desired target rate, and a rate tolerance, round 893 * the target rate to a possible, programmable rate for this DPLL. 894 * Rate tolerance is assumed to be set by the caller before this 895 * function is called. Attempts to select the minimum possible n 896 * within the tolerance to reduce power consumption. Stores the 897 * computed (m, n) in the DPLL's dpll_data structure so set_rate() 898 * will not need to call this (expensive) function again. Returns ~0 899 * if the target rate cannot be rounded, either because the rate is 900 * too low or because the rate tolerance is set too tightly; or the 901 * rounded rate upon success. 902 */ 903 long omap2_dpll_round_rate(struct clk *clk, unsigned long target_rate) 904 { 905 int m, n, r, e, scaled_max_m; 906 unsigned long scaled_rt_rp, new_rate; 907 int min_e = -1, min_e_m = -1, min_e_n = -1; 908 struct dpll_data *dd; 909 910 if (!clk || !clk->dpll_data) 911 return ~0; 912 913 dd = clk->dpll_data; 914 915 pr_debug("clock: starting DPLL round_rate for clock %s, target rate " 916 "%ld\n", clk->name, target_rate); 917 918 scaled_rt_rp = target_rate / (clk->parent->rate / DPLL_SCALE_FACTOR); 919 scaled_max_m = dd->max_multiplier * DPLL_SCALE_FACTOR; 920 921 dd->last_rounded_rate = 0; 922 923 for (n = dd->min_divider; n <= dd->max_divider; n++) { 924 925 /* Is the (input clk, divider) pair valid for the DPLL? */ 926 r = _dpll_test_fint(clk, n); 927 if (r == DPLL_FINT_UNDERFLOW) 928 break; 929 else if (r == DPLL_FINT_INVALID) 930 continue; 931 932 /* Compute the scaled DPLL multiplier, based on the divider */ 933 m = scaled_rt_rp * n; 934 935 /* 936 * Since we're counting n up, a m overflow means we 937 * can bail out completely (since as n increases in 938 * the next iteration, there's no way that m can 939 * increase beyond the current m) 940 */ 941 if (m > scaled_max_m) 942 break; 943 944 r = _dpll_test_mult(&m, n, &new_rate, target_rate, 945 clk->parent->rate); 946 947 /* m can't be set low enough for this n - try with a larger n */ 948 if (r == DPLL_MULT_UNDERFLOW) 949 continue; 950 951 e = target_rate - new_rate; 952 pr_debug("clock: n = %d: m = %d: rate error is %d " 953 "(new_rate = %ld)\n", n, m, e, new_rate); 954 955 if (min_e == -1 || 956 min_e >= (int)(abs(e) - dd->rate_tolerance)) { 957 min_e = e; 958 min_e_m = m; 959 min_e_n = n; 960 961 pr_debug("clock: found new least error %d\n", min_e); 962 963 /* We found good settings -- bail out now */ 964 if (min_e <= dd->rate_tolerance) 965 break; 966 } 967 } 968 969 if (min_e < 0) { 970 pr_debug("clock: error: target rate or tolerance too low\n"); 971 return ~0; 972 } 973 974 dd->last_rounded_m = min_e_m; 975 dd->last_rounded_n = min_e_n; 976 dd->last_rounded_rate = _dpll_compute_new_rate(clk->parent->rate, 977 min_e_m, min_e_n); 978 979 pr_debug("clock: final least error: e = %d, m = %d, n = %d\n", 980 min_e, min_e_m, min_e_n); 981 pr_debug("clock: final rate: %ld (target rate: %ld)\n", 982 dd->last_rounded_rate, target_rate); 983 984 return dd->last_rounded_rate; 985 } 986 987 /*------------------------------------------------------------------------- 988 * Omap2 clock reset and init functions 989 *-------------------------------------------------------------------------*/ 990 991 #ifdef CONFIG_OMAP_RESET_CLOCKS 992 void omap2_clk_disable_unused(struct clk *clk) 993 { 994 u32 regval32, v; 995 996 v = (clk->flags & INVERT_ENABLE) ? (1 << clk->enable_bit) : 0; 997 998 regval32 = __raw_readl(clk->enable_reg); 999 if ((regval32 & (1 << clk->enable_bit)) == v) 1000 return; 1001 1002 printk(KERN_INFO "Disabling unused clock \"%s\"\n", clk->name); 1003 _omap2_clk_disable(clk); 1004 } 1005 #endif 1006