1 /* 2 * OMAP2/3 clockdomain framework functions 3 * 4 * Copyright (C) 2008 Texas Instruments, Inc. 5 * Copyright (C) 2008 Nokia Corporation 6 * 7 * Written by Paul Walmsley and Jouni Högander 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 */ 13 #ifdef CONFIG_OMAP_DEBUG_CLOCKDOMAIN 14 # define DEBUG 15 #endif 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/limits.h> 25 #include <linux/err.h> 26 27 #include <linux/io.h> 28 29 #include <linux/bitops.h> 30 31 #include <mach/clock.h> 32 33 #include "prm.h" 34 #include "prm-regbits-24xx.h" 35 #include "cm.h" 36 37 #include <mach/powerdomain.h> 38 #include <mach/clockdomain.h> 39 40 /* clkdm_list contains all registered struct clockdomains */ 41 static LIST_HEAD(clkdm_list); 42 43 /* clkdm_mutex protects clkdm_list add and del ops */ 44 static DEFINE_MUTEX(clkdm_mutex); 45 46 /* array of powerdomain deps to be added/removed when clkdm in hwsup mode */ 47 static struct clkdm_pwrdm_autodep *autodeps; 48 49 50 /* Private functions */ 51 52 /* 53 * _autodep_lookup - resolve autodep pwrdm names to pwrdm pointers; store 54 * @autodep: struct clkdm_pwrdm_autodep * to resolve 55 * 56 * Resolve autodep powerdomain names to powerdomain pointers via 57 * pwrdm_lookup() and store the pointers in the autodep structure. An 58 * "autodep" is a powerdomain sleep/wakeup dependency that is 59 * automatically added and removed whenever clocks in the associated 60 * clockdomain are enabled or disabled (respectively) when the 61 * clockdomain is in hardware-supervised mode. Meant to be called 62 * once at clockdomain layer initialization, since these should remain 63 * fixed for a particular architecture. No return value. 64 */ 65 static void _autodep_lookup(struct clkdm_pwrdm_autodep *autodep) 66 { 67 struct powerdomain *pwrdm; 68 69 if (!autodep) 70 return; 71 72 if (!omap_chip_is(autodep->omap_chip)) 73 return; 74 75 pwrdm = pwrdm_lookup(autodep->pwrdm.name); 76 if (!pwrdm) { 77 pr_err("clockdomain: autodeps: powerdomain %s does not exist\n", 78 autodep->pwrdm.name); 79 pwrdm = ERR_PTR(-ENOENT); 80 } 81 autodep->pwrdm.ptr = pwrdm; 82 } 83 84 /* 85 * _clkdm_add_autodeps - add auto sleepdeps/wkdeps to clkdm upon clock enable 86 * @clkdm: struct clockdomain * 87 * 88 * Add the "autodep" sleep & wakeup dependencies to clockdomain 'clkdm' 89 * in hardware-supervised mode. Meant to be called from clock framework 90 * when a clock inside clockdomain 'clkdm' is enabled. No return value. 91 */ 92 static void _clkdm_add_autodeps(struct clockdomain *clkdm) 93 { 94 struct clkdm_pwrdm_autodep *autodep; 95 96 for (autodep = autodeps; autodep->pwrdm.ptr; autodep++) { 97 if (IS_ERR(autodep->pwrdm.ptr)) 98 continue; 99 100 if (!omap_chip_is(autodep->omap_chip)) 101 continue; 102 103 pr_debug("clockdomain: adding %s sleepdep/wkdep for " 104 "pwrdm %s\n", autodep->pwrdm.ptr->name, 105 clkdm->pwrdm.ptr->name); 106 107 pwrdm_add_sleepdep(clkdm->pwrdm.ptr, autodep->pwrdm.ptr); 108 pwrdm_add_wkdep(clkdm->pwrdm.ptr, autodep->pwrdm.ptr); 109 } 110 } 111 112 /* 113 * _clkdm_add_autodeps - remove auto sleepdeps/wkdeps from clkdm 114 * @clkdm: struct clockdomain * 115 * 116 * Remove the "autodep" sleep & wakeup dependencies from clockdomain 'clkdm' 117 * in hardware-supervised mode. Meant to be called from clock framework 118 * when a clock inside clockdomain 'clkdm' is disabled. No return value. 119 */ 120 static void _clkdm_del_autodeps(struct clockdomain *clkdm) 121 { 122 struct clkdm_pwrdm_autodep *autodep; 123 124 for (autodep = autodeps; autodep->pwrdm.ptr; autodep++) { 125 if (IS_ERR(autodep->pwrdm.ptr)) 126 continue; 127 128 if (!omap_chip_is(autodep->omap_chip)) 129 continue; 130 131 pr_debug("clockdomain: removing %s sleepdep/wkdep for " 132 "pwrdm %s\n", autodep->pwrdm.ptr->name, 133 clkdm->pwrdm.ptr->name); 134 135 pwrdm_del_sleepdep(clkdm->pwrdm.ptr, autodep->pwrdm.ptr); 136 pwrdm_del_wkdep(clkdm->pwrdm.ptr, autodep->pwrdm.ptr); 137 } 138 } 139 140 141 static struct clockdomain *_clkdm_lookup(const char *name) 142 { 143 struct clockdomain *clkdm, *temp_clkdm; 144 145 if (!name) 146 return NULL; 147 148 clkdm = NULL; 149 150 list_for_each_entry(temp_clkdm, &clkdm_list, node) { 151 if (!strcmp(name, temp_clkdm->name)) { 152 clkdm = temp_clkdm; 153 break; 154 } 155 } 156 157 return clkdm; 158 } 159 160 161 /* Public functions */ 162 163 /** 164 * clkdm_init - set up the clockdomain layer 165 * @clkdms: optional pointer to an array of clockdomains to register 166 * @init_autodeps: optional pointer to an array of autodeps to register 167 * 168 * Set up internal state. If a pointer to an array of clockdomains 169 * was supplied, loop through the list of clockdomains, register all 170 * that are available on the current platform. Similarly, if a 171 * pointer to an array of clockdomain-powerdomain autodependencies was 172 * provided, register those. No return value. 173 */ 174 void clkdm_init(struct clockdomain **clkdms, 175 struct clkdm_pwrdm_autodep *init_autodeps) 176 { 177 struct clockdomain **c = NULL; 178 struct clkdm_pwrdm_autodep *autodep = NULL; 179 180 if (clkdms) 181 for (c = clkdms; *c; c++) 182 clkdm_register(*c); 183 184 autodeps = init_autodeps; 185 if (autodeps) 186 for (autodep = autodeps; autodep->pwrdm.ptr; autodep++) 187 _autodep_lookup(autodep); 188 } 189 190 /** 191 * clkdm_register - register a clockdomain 192 * @clkdm: struct clockdomain * to register 193 * 194 * Adds a clockdomain to the internal clockdomain list. 195 * Returns -EINVAL if given a null pointer, -EEXIST if a clockdomain is 196 * already registered by the provided name, or 0 upon success. 197 */ 198 int clkdm_register(struct clockdomain *clkdm) 199 { 200 int ret = -EINVAL; 201 struct powerdomain *pwrdm; 202 203 if (!clkdm || !clkdm->name) 204 return -EINVAL; 205 206 if (!omap_chip_is(clkdm->omap_chip)) 207 return -EINVAL; 208 209 pwrdm = pwrdm_lookup(clkdm->pwrdm.name); 210 if (!pwrdm) { 211 pr_err("clockdomain: %s: powerdomain %s does not exist\n", 212 clkdm->name, clkdm->pwrdm.name); 213 return -EINVAL; 214 } 215 clkdm->pwrdm.ptr = pwrdm; 216 217 mutex_lock(&clkdm_mutex); 218 /* Verify that the clockdomain is not already registered */ 219 if (_clkdm_lookup(clkdm->name)) { 220 ret = -EEXIST; 221 goto cr_unlock; 222 } 223 224 list_add(&clkdm->node, &clkdm_list); 225 226 pwrdm_add_clkdm(pwrdm, clkdm); 227 228 pr_debug("clockdomain: registered %s\n", clkdm->name); 229 ret = 0; 230 231 cr_unlock: 232 mutex_unlock(&clkdm_mutex); 233 234 return ret; 235 } 236 237 /** 238 * clkdm_unregister - unregister a clockdomain 239 * @clkdm: struct clockdomain * to unregister 240 * 241 * Removes a clockdomain from the internal clockdomain list. Returns 242 * -EINVAL if clkdm argument is NULL. 243 */ 244 int clkdm_unregister(struct clockdomain *clkdm) 245 { 246 if (!clkdm) 247 return -EINVAL; 248 249 pwrdm_del_clkdm(clkdm->pwrdm.ptr, clkdm); 250 251 mutex_lock(&clkdm_mutex); 252 list_del(&clkdm->node); 253 mutex_unlock(&clkdm_mutex); 254 255 pr_debug("clockdomain: unregistered %s\n", clkdm->name); 256 257 return 0; 258 } 259 260 /** 261 * clkdm_lookup - look up a clockdomain by name, return a pointer 262 * @name: name of clockdomain 263 * 264 * Find a registered clockdomain by its name. Returns a pointer to the 265 * struct clockdomain if found, or NULL otherwise. 266 */ 267 struct clockdomain *clkdm_lookup(const char *name) 268 { 269 struct clockdomain *clkdm, *temp_clkdm; 270 271 if (!name) 272 return NULL; 273 274 clkdm = NULL; 275 276 mutex_lock(&clkdm_mutex); 277 list_for_each_entry(temp_clkdm, &clkdm_list, node) { 278 if (!strcmp(name, temp_clkdm->name)) { 279 clkdm = temp_clkdm; 280 break; 281 } 282 } 283 mutex_unlock(&clkdm_mutex); 284 285 return clkdm; 286 } 287 288 /** 289 * clkdm_for_each - call function on each registered clockdomain 290 * @fn: callback function * 291 * 292 * Call the supplied function for each registered clockdomain. 293 * The callback function can return anything but 0 to bail 294 * out early from the iterator. The callback function is called with 295 * the clkdm_mutex held, so no clockdomain structure manipulation 296 * functions should be called from the callback, although hardware 297 * clockdomain control functions are fine. Returns the last return 298 * value of the callback function, which should be 0 for success or 299 * anything else to indicate failure; or -EINVAL if the function pointer 300 * is null. 301 */ 302 int clkdm_for_each(int (*fn)(struct clockdomain *clkdm, void *user), 303 void *user) 304 { 305 struct clockdomain *clkdm; 306 int ret = 0; 307 308 if (!fn) 309 return -EINVAL; 310 311 mutex_lock(&clkdm_mutex); 312 list_for_each_entry(clkdm, &clkdm_list, node) { 313 ret = (*fn)(clkdm, user); 314 if (ret) 315 break; 316 } 317 mutex_unlock(&clkdm_mutex); 318 319 return ret; 320 } 321 322 323 /** 324 * clkdm_get_pwrdm - return a ptr to the pwrdm that this clkdm resides in 325 * @clkdm: struct clockdomain * 326 * 327 * Return a pointer to the struct powerdomain that the specified clockdomain 328 * 'clkdm' exists in, or returns NULL if clkdm argument is NULL. 329 */ 330 struct powerdomain *clkdm_get_pwrdm(struct clockdomain *clkdm) 331 { 332 if (!clkdm) 333 return NULL; 334 335 return clkdm->pwrdm.ptr; 336 } 337 338 339 /* Hardware clockdomain control */ 340 341 /** 342 * omap2_clkdm_clktrctrl_read - read the clkdm's current state transition mode 343 * @clk: struct clk * of a clockdomain 344 * 345 * Return the clockdomain's current state transition mode from the 346 * corresponding domain CM_CLKSTCTRL register. Returns -EINVAL if clk 347 * is NULL or the current mode upon success. 348 */ 349 static int omap2_clkdm_clktrctrl_read(struct clockdomain *clkdm) 350 { 351 u32 v; 352 353 if (!clkdm) 354 return -EINVAL; 355 356 v = cm_read_mod_reg(clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL); 357 v &= clkdm->clktrctrl_mask; 358 v >>= __ffs(clkdm->clktrctrl_mask); 359 360 return v; 361 } 362 363 /** 364 * omap2_clkdm_sleep - force clockdomain sleep transition 365 * @clkdm: struct clockdomain * 366 * 367 * Instruct the CM to force a sleep transition on the specified 368 * clockdomain 'clkdm'. Returns -EINVAL if clk is NULL or if 369 * clockdomain does not support software-initiated sleep; 0 upon 370 * success. 371 */ 372 int omap2_clkdm_sleep(struct clockdomain *clkdm) 373 { 374 if (!clkdm) 375 return -EINVAL; 376 377 if (!(clkdm->flags & CLKDM_CAN_FORCE_SLEEP)) { 378 pr_debug("clockdomain: %s does not support forcing " 379 "sleep via software\n", clkdm->name); 380 return -EINVAL; 381 } 382 383 pr_debug("clockdomain: forcing sleep on %s\n", clkdm->name); 384 385 if (cpu_is_omap24xx()) { 386 387 cm_set_mod_reg_bits(OMAP24XX_FORCESTATE, 388 clkdm->pwrdm.ptr->prcm_offs, PM_PWSTCTRL); 389 390 } else if (cpu_is_omap34xx()) { 391 392 u32 v = (OMAP34XX_CLKSTCTRL_FORCE_SLEEP << 393 __ffs(clkdm->clktrctrl_mask)); 394 395 cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, v, 396 clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL); 397 398 } else { 399 BUG(); 400 }; 401 402 return 0; 403 } 404 405 /** 406 * omap2_clkdm_wakeup - force clockdomain wakeup transition 407 * @clkdm: struct clockdomain * 408 * 409 * Instruct the CM to force a wakeup transition on the specified 410 * clockdomain 'clkdm'. Returns -EINVAL if clkdm is NULL or if the 411 * clockdomain does not support software-controlled wakeup; 0 upon 412 * success. 413 */ 414 int omap2_clkdm_wakeup(struct clockdomain *clkdm) 415 { 416 if (!clkdm) 417 return -EINVAL; 418 419 if (!(clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)) { 420 pr_debug("clockdomain: %s does not support forcing " 421 "wakeup via software\n", clkdm->name); 422 return -EINVAL; 423 } 424 425 pr_debug("clockdomain: forcing wakeup on %s\n", clkdm->name); 426 427 if (cpu_is_omap24xx()) { 428 429 cm_clear_mod_reg_bits(OMAP24XX_FORCESTATE, 430 clkdm->pwrdm.ptr->prcm_offs, PM_PWSTCTRL); 431 432 } else if (cpu_is_omap34xx()) { 433 434 u32 v = (OMAP34XX_CLKSTCTRL_FORCE_WAKEUP << 435 __ffs(clkdm->clktrctrl_mask)); 436 437 cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, v, 438 clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL); 439 440 } else { 441 BUG(); 442 }; 443 444 return 0; 445 } 446 447 /** 448 * omap2_clkdm_allow_idle - enable hwsup idle transitions for clkdm 449 * @clkdm: struct clockdomain * 450 * 451 * Allow the hardware to automatically switch the clockdomain into 452 * active or idle states, as needed by downstream clocks. If the 453 * clockdomain has any downstream clocks enabled in the clock 454 * framework, wkdep/sleepdep autodependencies are added; this is so 455 * device drivers can read and write to the device. No return value. 456 */ 457 void omap2_clkdm_allow_idle(struct clockdomain *clkdm) 458 { 459 u32 v; 460 461 if (!clkdm) 462 return; 463 464 if (!(clkdm->flags & CLKDM_CAN_ENABLE_AUTO)) { 465 pr_debug("clock: automatic idle transitions cannot be enabled " 466 "on clockdomain %s\n", clkdm->name); 467 return; 468 } 469 470 pr_debug("clockdomain: enabling automatic idle transitions for %s\n", 471 clkdm->name); 472 473 if (atomic_read(&clkdm->usecount) > 0) 474 _clkdm_add_autodeps(clkdm); 475 476 if (cpu_is_omap24xx()) 477 v = OMAP24XX_CLKSTCTRL_ENABLE_AUTO; 478 else if (cpu_is_omap34xx()) 479 v = OMAP34XX_CLKSTCTRL_ENABLE_AUTO; 480 else 481 BUG(); 482 483 484 cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, 485 v << __ffs(clkdm->clktrctrl_mask), 486 clkdm->pwrdm.ptr->prcm_offs, 487 CM_CLKSTCTRL); 488 489 pwrdm_clkdm_state_switch(clkdm); 490 } 491 492 /** 493 * omap2_clkdm_deny_idle - disable hwsup idle transitions for clkdm 494 * @clkdm: struct clockdomain * 495 * 496 * Prevent the hardware from automatically switching the clockdomain 497 * into inactive or idle states. If the clockdomain has downstream 498 * clocks enabled in the clock framework, wkdep/sleepdep 499 * autodependencies are removed. No return value. 500 */ 501 void omap2_clkdm_deny_idle(struct clockdomain *clkdm) 502 { 503 u32 v; 504 505 if (!clkdm) 506 return; 507 508 if (!(clkdm->flags & CLKDM_CAN_DISABLE_AUTO)) { 509 pr_debug("clockdomain: automatic idle transitions cannot be " 510 "disabled on %s\n", clkdm->name); 511 return; 512 } 513 514 pr_debug("clockdomain: disabling automatic idle transitions for %s\n", 515 clkdm->name); 516 517 if (cpu_is_omap24xx()) 518 v = OMAP24XX_CLKSTCTRL_DISABLE_AUTO; 519 else if (cpu_is_omap34xx()) 520 v = OMAP34XX_CLKSTCTRL_DISABLE_AUTO; 521 else 522 BUG(); 523 524 cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, 525 v << __ffs(clkdm->clktrctrl_mask), 526 clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL); 527 528 if (atomic_read(&clkdm->usecount) > 0) 529 _clkdm_del_autodeps(clkdm); 530 } 531 532 533 /* Clockdomain-to-clock framework interface code */ 534 535 /** 536 * omap2_clkdm_clk_enable - add an enabled downstream clock to this clkdm 537 * @clkdm: struct clockdomain * 538 * @clk: struct clk * of the enabled downstream clock 539 * 540 * Increment the usecount of this clockdomain 'clkdm' and ensure that 541 * it is awake. Intended to be called by clk_enable() code. If the 542 * clockdomain is in software-supervised idle mode, force the 543 * clockdomain to wake. If the clockdomain is in hardware-supervised 544 * idle mode, add clkdm-pwrdm autodependencies, to ensure that devices 545 * in the clockdomain can be read from/written to by on-chip processors. 546 * Returns -EINVAL if passed null pointers; returns 0 upon success or 547 * if the clockdomain is in hwsup idle mode. 548 */ 549 int omap2_clkdm_clk_enable(struct clockdomain *clkdm, struct clk *clk) 550 { 551 int v; 552 553 /* 554 * XXX Rewrite this code to maintain a list of enabled 555 * downstream clocks for debugging purposes? 556 */ 557 558 if (!clkdm || !clk) 559 return -EINVAL; 560 561 if (atomic_inc_return(&clkdm->usecount) > 1) 562 return 0; 563 564 /* Clockdomain now has one enabled downstream clock */ 565 566 pr_debug("clockdomain: clkdm %s: clk %s now enabled\n", clkdm->name, 567 clk->name); 568 569 v = omap2_clkdm_clktrctrl_read(clkdm); 570 571 if ((cpu_is_omap34xx() && v == OMAP34XX_CLKSTCTRL_ENABLE_AUTO) || 572 (cpu_is_omap24xx() && v == OMAP24XX_CLKSTCTRL_ENABLE_AUTO)) 573 _clkdm_add_autodeps(clkdm); 574 else 575 omap2_clkdm_wakeup(clkdm); 576 577 pwrdm_wait_transition(clkdm->pwrdm.ptr); 578 pwrdm_clkdm_state_switch(clkdm); 579 580 return 0; 581 } 582 583 /** 584 * omap2_clkdm_clk_disable - remove an enabled downstream clock from this clkdm 585 * @clkdm: struct clockdomain * 586 * @clk: struct clk * of the disabled downstream clock 587 * 588 * Decrement the usecount of this clockdomain 'clkdm'. Intended to be 589 * called by clk_disable() code. If the usecount goes to 0, put the 590 * clockdomain to sleep (software-supervised mode) or remove the 591 * clkdm-pwrdm autodependencies (hardware-supervised mode). Returns 592 * -EINVAL if passed null pointers; -ERANGE if the clkdm usecount 593 * underflows and debugging is enabled; or returns 0 upon success or 594 * if the clockdomain is in hwsup idle mode. 595 */ 596 int omap2_clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk) 597 { 598 int v; 599 600 /* 601 * XXX Rewrite this code to maintain a list of enabled 602 * downstream clocks for debugging purposes? 603 */ 604 605 if (!clkdm || !clk) 606 return -EINVAL; 607 608 #ifdef DEBUG 609 if (atomic_read(&clkdm->usecount) == 0) { 610 WARN_ON(1); /* underflow */ 611 return -ERANGE; 612 } 613 #endif 614 615 if (atomic_dec_return(&clkdm->usecount) > 0) 616 return 0; 617 618 /* All downstream clocks of this clockdomain are now disabled */ 619 620 pr_debug("clockdomain: clkdm %s: clk %s now disabled\n", clkdm->name, 621 clk->name); 622 623 v = omap2_clkdm_clktrctrl_read(clkdm); 624 625 if ((cpu_is_omap34xx() && v == OMAP34XX_CLKSTCTRL_ENABLE_AUTO) || 626 (cpu_is_omap24xx() && v == OMAP24XX_CLKSTCTRL_ENABLE_AUTO)) 627 _clkdm_del_autodeps(clkdm); 628 else 629 omap2_clkdm_sleep(clkdm); 630 631 pwrdm_clkdm_state_switch(clkdm); 632 633 return 0; 634 } 635 636