arch/arm/mach-at91rm9200/clock.c

   1 /*
   2  * linux/arch/arm/mach-at91rm9200/clock.c
   3  *
   4  * Copyright (C) 2005 David Brownell
   5  * Copyright (C) 2005 Ivan Kokshaysky
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/fs.h>
  17 #include <linux/debugfs.h>
  18 #include <linux/seq_file.h>
  19 #include <linux/list.h>
  20 #include <linux/errno.h>
  21 #include <linux/err.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/delay.h>
  24 #include <linux/clk.h>
  25
  26 #include <asm/semaphore.h>
  27 #include <asm/io.h>
  28 #include <asm/mach-types.h>
  29
  30 #include <asm/hardware.h>
  31
  32 #include "generic.h"
  33
  34
  35 /*
  36  * There's a lot more which can be done with clocks, including cpufreq
  37  * integration, slow clock mode support (for system suspend), letting
  38  * PLLB be used at other rates (on boards that don't need USB), etc.
  39  */
  40
  41 struct clk {
  42         const char      *name;          /* unique clock name */
  43         const char      *function;      /* function of the clock */
  44         struct device   *dev;           /* device associated with function */
  45         unsigned long   rate_hz;
  46         struct clk      *parent;
  47         u32             pmc_mask;
  48         void            (*mode)(struct clk *, int);
  49         unsigned        id:2;           /* PCK0..3, or 32k/main/a/b */
  50         unsigned        primary:1;
  51         unsigned        pll:1;
  52         unsigned        programmable:1;
  53         u16             users;
  54 };
  55
  56 static spinlock_t       clk_lock;
  57 static u32              at91_pllb_usb_init;
  58
  59 /*
  60  * Four primary clock sources:  two crystal oscillators (32K, main), and
  61  * two PLLs.  PLLA usually runs the master clock; and PLLB must run at
  62  * 48 MHz (unless no USB function clocks are needed).  The main clock and
  63  * both PLLs are turned off to run in "slow clock mode" (system suspend).
  64  */
  65 static struct clk clk32k = {
  66         .name           = "clk32k",
  67         .rate_hz        = AT91_SLOW_CLOCK,
  68         .users          = 1,            /* always on */
  69         .id             = 0,
  70         .primary        = 1,
  71 };
  72 static struct clk main_clk = {
  73         .name           = "main",
  74         .pmc_mask       = AT91_PMC_MOSCS,       /* in PMC_SR */
  75         .id             = 1,
  76         .primary        = 1,
  77 };
  78 static struct clk plla = {
  79         .name           = "plla",
  80         .parent         = &main_clk,
  81         .pmc_mask       = AT91_PMC_LOCKA,       /* in PMC_SR */
  82         .id             = 2,
  83         .primary        = 1,
  84         .pll            = 1,
  85 };
  86
  87 static void pllb_mode(struct clk *clk, int is_on)
  88 {
  89         u32     value;
  90
  91         if (is_on) {
  92                 is_on = AT91_PMC_LOCKB;
  93                 value = at91_pllb_usb_init;
  94         } else
  95                 value = 0;
  96
  97         at91_sys_write(AT91_CKGR_PLLBR, value);
  98
  99         do {
 100                 cpu_relax();
 101         } while ((at91_sys_read(AT91_PMC_SR) & AT91_PMC_LOCKB) != is_on);
 102 }
 103
 104 static struct clk pllb = {
 105         .name           = "pllb",
 106         .parent         = &main_clk,
 107         .pmc_mask       = AT91_PMC_LOCKB,       /* in PMC_SR */
 108         .mode           = pllb_mode,
 109         .id             = 3,
 110         .primary        = 1,
 111         .pll            = 1,
 112 };
 113
 114 static void pmc_sys_mode(struct clk *clk, int is_on)
 115 {
 116         if (is_on)
 117                 at91_sys_write(AT91_PMC_SCER, clk->pmc_mask);
 118         else
 119                 at91_sys_write(AT91_PMC_SCDR, clk->pmc_mask);
 120 }
 121
 122 /* USB function clocks (PLLB must be 48 MHz) */
 123 static struct clk udpck = {
 124         .name           = "udpck",
 125         .parent         = &pllb,
 126         .pmc_mask       = AT91_PMC_UDP,
 127         .mode           = pmc_sys_mode,
 128 };
 129 static struct clk uhpck = {
 130         .name           = "uhpck",
 131         .parent         = &pllb,
 132         .pmc_mask       = AT91_PMC_UHP,
 133         .mode           = pmc_sys_mode,
 134 };
 135
 136 #ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
 137 /*
 138  * The four programmable clocks can be parented by any primary clock.
 139  * You must configure pin multiplexing to bring these signals out.
 140  */
 141 static struct clk pck0 = {
 142         .name           = "pck0",
 143         .pmc_mask       = AT91_PMC_PCK0,
 144         .mode           = pmc_sys_mode,
 145         .programmable   = 1,
 146         .id             = 0,
 147 };
 148 static struct clk pck1 = {
 149         .name           = "pck1",
 150         .pmc_mask       = AT91_PMC_PCK1,
 151         .mode           = pmc_sys_mode,
 152         .programmable   = 1,
 153         .id             = 1,
 154 };
 155 static struct clk pck2 = {
 156         .name           = "pck2",
 157         .pmc_mask       = AT91_PMC_PCK2,
 158         .mode           = pmc_sys_mode,
 159         .programmable   = 1,
 160         .id             = 2,
 161 };
 162 static struct clk pck3 = {
 163         .name           = "pck3",
 164         .pmc_mask       = AT91_PMC_PCK3,
 165         .mode           = pmc_sys_mode,
 166         .programmable   = 1,
 167         .id             = 3,
 168 };
 169 #endif  /* CONFIG_AT91_PROGRAMMABLE_CLOCKS */
 170
 171
 172 /*
 173  * The master clock is divided from the CPU clock (by 1-4).  It's used for
 174  * memory, interfaces to on-chip peripherals, the AIC, and sometimes more
 175  * (e.g baud rate generation).  It's sourced from one of the primary clocks.
 176  */
 177 static struct clk mck = {
 178         .name           = "mck",
 179         .pmc_mask       = AT91_PMC_MCKRDY,      /* in PMC_SR */
 180 };
 181
 182 static void pmc_periph_mode(struct clk *clk, int is_on)
 183 {
 184         if (is_on)
 185                 at91_sys_write(AT91_PMC_PCER, clk->pmc_mask);
 186         else
 187                 at91_sys_write(AT91_PMC_PCDR, clk->pmc_mask);
 188 }
 189
 190 static struct clk udc_clk = {
 191         .name           = "udc_clk",
 192         .parent         = &mck,
 193         .pmc_mask       = 1 << AT91RM9200_ID_UDP,
 194         .mode           = pmc_periph_mode,
 195 };
 196 static struct clk ohci_clk = {
 197         .name           = "ohci_clk",
 198         .parent         = &mck,
 199         .pmc_mask       = 1 << AT91RM9200_ID_UHP,
 200         .mode           = pmc_periph_mode,
 201 };
 202 static struct clk ether_clk = {
 203         .name           = "ether_clk",
 204         .parent         = &mck,
 205         .pmc_mask       = 1 << AT91RM9200_ID_EMAC,
 206         .mode           = pmc_periph_mode,
 207 };
 208 static struct clk mmc_clk = {
 209         .name           = "mci_clk",
 210         .parent         = &mck,
 211         .pmc_mask       = 1 << AT91RM9200_ID_MCI,
 212         .mode           = pmc_periph_mode,
 213 };
 214 static struct clk twi_clk = {
 215         .name           = "twi_clk",
 216         .parent         = &mck,
 217         .pmc_mask       = 1 << AT91RM9200_ID_TWI,
 218         .mode           = pmc_periph_mode,
 219 };
 220 static struct clk usart0_clk = {
 221         .name           = "usart0_clk",
 222         .parent         = &mck,
 223         .pmc_mask       = 1 << AT91RM9200_ID_US0,
 224         .mode           = pmc_periph_mode,
 225 };
 226 static struct clk usart1_clk = {
 227         .name           = "usart1_clk",
 228         .parent         = &mck,
 229         .pmc_mask       = 1 << AT91RM9200_ID_US1,
 230         .mode           = pmc_periph_mode,
 231 };
 232 static struct clk usart2_clk = {
 233         .name           = "usart2_clk",
 234         .parent         = &mck,
 235         .pmc_mask       = 1 << AT91RM9200_ID_US2,
 236         .mode           = pmc_periph_mode,
 237 };
 238 static struct clk usart3_clk = {
 239         .name           = "usart3_clk",
 240         .parent         = &mck,
 241         .pmc_mask       = 1 << AT91RM9200_ID_US3,
 242         .mode           = pmc_periph_mode,
 243 };
 244 static struct clk spi_clk = {
 245         .name           = "spi0_clk",
 246         .parent         = &mck,
 247         .pmc_mask       = 1 << AT91RM9200_ID_SPI,
 248         .mode           = pmc_periph_mode,
 249 };
 250 static struct clk pioA_clk = {
 251         .name           = "pioA_clk",
 252         .parent         = &mck,
 253         .pmc_mask       = 1 << AT91RM9200_ID_PIOA,
 254         .mode           = pmc_periph_mode,
 255 };
 256 static struct clk pioB_clk = {
 257         .name           = "pioB_clk",
 258         .parent         = &mck,
 259         .pmc_mask       = 1 << AT91RM9200_ID_PIOB,
 260         .mode           = pmc_periph_mode,
 261 };
 262 static struct clk pioC_clk = {
 263         .name           = "pioC_clk",
 264         .parent         = &mck,
 265         .pmc_mask       = 1 << AT91RM9200_ID_PIOC,
 266         .mode           = pmc_periph_mode,
 267 };
 268 static struct clk pioD_clk = {
 269         .name           = "pioD_clk",
 270         .parent         = &mck,
 271         .pmc_mask       = 1 << AT91RM9200_ID_PIOD,
 272         .mode           = pmc_periph_mode,
 273 };
 274
 275 static struct clk *const clock_list[] = {
 276         /* four primary clocks -- MUST BE FIRST! */
 277         &clk32k,
 278         &main_clk,
 279         &plla,
 280         &pllb,
 281
 282         /* PLLB children (USB) */
 283         &udpck,
 284         &uhpck,
 285
 286 #ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
 287         /* programmable clocks */
 288         &pck0,
 289         &pck1,
 290         &pck2,
 291         &pck3,
 292 #endif  /* CONFIG_AT91_PROGRAMMABLE_CLOCKS */
 293
 294         /* MCK and peripherals */
 295         &mck,
 296         &usart0_clk,
 297         &usart1_clk,
 298         &usart2_clk,
 299         &usart3_clk,
 300         &mmc_clk,
 301         &udc_clk,
 302         &twi_clk,
 303         &spi_clk,
 304         &pioA_clk,
 305         &pioB_clk,
 306         &pioC_clk,
 307         &pioD_clk,
 308         // ssc0..ssc2
 309         // tc0..tc5
 310         // irq0..irq6
 311         &ohci_clk,
 312         &ether_clk,
 313 };
 314
 315
 316 /*
 317  * Associate a particular clock with a function (eg, "uart") and device.
 318  * The drivers can then request the same 'function' with several different
 319  * devices and not care about which clock name to use.
 320  */
 321 void __init at91_clock_associate(const char *id, struct device *dev, const char *func)
 322 {
 323         struct clk *clk = clk_get(NULL, id);
 324
 325         if (!dev || !clk || !IS_ERR(clk_get(dev, func)))
 326                 return;
 327
 328         clk->function = func;
 329         clk->dev = dev;
 330 }
 331
 332 /* clocks are all static for now; no refcounting necessary */
 333 struct clk *clk_get(struct device *dev, const char *id)
 334 {
 335         int i;
 336
 337         for (i = 0; i < ARRAY_SIZE(clock_list); i++) {
 338                 struct clk *clk = clock_list[i];
 339
 340                 if (strcmp(id, clk->name) == 0)
 341                         return clk;
 342                 if (clk->function && (dev == clk->dev) && strcmp(id, clk->function) == 0)
 343                         return clk;
 344         }
 345
 346         return ERR_PTR(-ENOENT);
 347 }
 348 EXPORT_SYMBOL(clk_get);
 349
 350 void clk_put(struct clk *clk)
 351 {
 352 }
 353 EXPORT_SYMBOL(clk_put);
 354
 355 static void __clk_enable(struct clk *clk)
 356 {
 357         if (clk->parent)
 358                 __clk_enable(clk->parent);
 359         if (clk->users++ == 0 && clk->mode)
 360                 clk->mode(clk, 1);
 361 }
 362
 363 int clk_enable(struct clk *clk)
 364 {
 365         unsigned long   flags;
 366
 367         spin_lock_irqsave(&clk_lock, flags);
 368         __clk_enable(clk);
 369         spin_unlock_irqrestore(&clk_lock, flags);
 370         return 0;
 371 }
 372 EXPORT_SYMBOL(clk_enable);
 373
 374 static void __clk_disable(struct clk *clk)
 375 {
 376         BUG_ON(clk->users == 0);
 377         if (--clk->users == 0 && clk->mode)
 378                 clk->mode(clk, 0);
 379         if (clk->parent)
 380                 __clk_disable(clk->parent);
 381 }
 382
 383 void clk_disable(struct clk *clk)
 384 {
 385         unsigned long   flags;
 386
 387         spin_lock_irqsave(&clk_lock, flags);
 388         __clk_disable(clk);
 389         spin_unlock_irqrestore(&clk_lock, flags);
 390 }
 391 EXPORT_SYMBOL(clk_disable);
 392
 393 unsigned long clk_get_rate(struct clk *clk)
 394 {
 395         unsigned long   flags;
 396         unsigned long   rate;
 397
 398         spin_lock_irqsave(&clk_lock, flags);
 399         for (;;) {
 400                 rate = clk->rate_hz;
 401                 if (rate || !clk->parent)
 402                         break;
 403                 clk = clk->parent;
 404         }
 405         spin_unlock_irqrestore(&clk_lock, flags);
 406         return rate;
 407 }
 408 EXPORT_SYMBOL(clk_get_rate);
 409
 410 /*------------------------------------------------------------------------*/
 411
 412 #ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
 413
 414 /*
 415  * For now, only the programmable clocks support reparenting (MCK could
 416  * do this too, with care) or rate changing (the PLLs could do this too,
 417  * ditto MCK but that's more for cpufreq).  Drivers may reparent to get
 418  * a better rate match; we don't.
 419  */
 420
 421 long clk_round_rate(struct clk *clk, unsigned long rate)
 422 {
 423         unsigned long   flags;
 424         unsigned        prescale;
 425         unsigned long   actual;
 426
 427         if (!clk->programmable)
 428                 return -EINVAL;
 429         spin_lock_irqsave(&clk_lock, flags);
 430
 431         actual = clk->parent->rate_hz;
 432         for (prescale = 0; prescale < 7; prescale++) {
 433                 if (actual && actual <= rate)
 434                         break;
 435                 actual >>= 1;
 436         }
 437
 438         spin_unlock_irqrestore(&clk_lock, flags);
 439         return (prescale < 7) ? actual : -ENOENT;
 440 }
 441 EXPORT_SYMBOL(clk_round_rate);
 442
 443 int clk_set_rate(struct clk *clk, unsigned long rate)
 444 {
 445         unsigned long   flags;
 446         unsigned        prescale;
 447         unsigned long   actual;
 448
 449         if (!clk->programmable)
 450                 return -EINVAL;
 451         if (clk->users)
 452                 return -EBUSY;
 453         spin_lock_irqsave(&clk_lock, flags);
 454
 455         actual = clk->parent->rate_hz;
 456         for (prescale = 0; prescale < 7; prescale++) {
 457                 if (actual && actual <= rate) {
 458                         u32     pckr;
 459
 460                         pckr = at91_sys_read(AT91_PMC_PCKR(clk->id));
 461                         pckr &= AT91_PMC_CSS_PLLB;      /* clock selection */
 462                         pckr |= prescale << 2;
 463                         at91_sys_write(AT91_PMC_PCKR(clk->id), pckr);
 464                         clk->rate_hz = actual;
 465                         break;
 466                 }
 467                 actual >>= 1;
 468         }
 469
 470         spin_unlock_irqrestore(&clk_lock, flags);
 471         return (prescale < 7) ? actual : -ENOENT;
 472 }
 473 EXPORT_SYMBOL(clk_set_rate);
 474
 475 struct clk *clk_get_parent(struct clk *clk)
 476 {
 477         return clk->parent;
 478 }
 479 EXPORT_SYMBOL(clk_get_parent);
 480
 481 int clk_set_parent(struct clk *clk, struct clk *parent)
 482 {
 483         unsigned long   flags;
 484
 485         if (clk->users)
 486                 return -EBUSY;
 487         if (!parent->primary || !clk->programmable)
 488                 return -EINVAL;
 489         spin_lock_irqsave(&clk_lock, flags);
 490
 491         clk->rate_hz = parent->rate_hz;
 492         clk->parent = parent;
 493         at91_sys_write(AT91_PMC_PCKR(clk->id), parent->id);
 494
 495         spin_unlock_irqrestore(&clk_lock, flags);
 496         return 0;
 497 }
 498 EXPORT_SYMBOL(clk_set_parent);
 499
 500 #endif  /* CONFIG_AT91_PROGRAMMABLE_CLOCKS */
 501
 502 /*------------------------------------------------------------------------*/
 503
 504 #ifdef CONFIG_DEBUG_FS
 505
 506 static int at91_clk_show(struct seq_file *s, void *unused)
 507 {
 508         u32             scsr, pcsr, sr;
 509         unsigned        i;
 510
 511         seq_printf(s, "SCSR = %8x\n", scsr = at91_sys_read(AT91_PMC_SCSR));
 512         seq_printf(s, "PCSR = %8x\n", pcsr = at91_sys_read(AT91_PMC_PCSR));
 513
 514         seq_printf(s, "MOR  = %8x\n", at91_sys_read(AT91_CKGR_MOR));
 515         seq_printf(s, "MCFR = %8x\n", at91_sys_read(AT91_CKGR_MCFR));
 516         seq_printf(s, "PLLA = %8x\n", at91_sys_read(AT91_CKGR_PLLAR));
 517         seq_printf(s, "PLLB = %8x\n", at91_sys_read(AT91_CKGR_PLLBR));
 518
 519         seq_printf(s, "MCKR = %8x\n", at91_sys_read(AT91_PMC_MCKR));
 520         for (i = 0; i < 4; i++)
 521                 seq_printf(s, "PCK%d = %8x\n", i, at91_sys_read(AT91_PMC_PCKR(i)));
 522         seq_printf(s, "SR   = %8x\n", sr = at91_sys_read(AT91_PMC_SR));
 523
 524         seq_printf(s, "\n");
 525
 526         for (i = 0; i < ARRAY_SIZE(clock_list); i++) {
 527                 char            *state;
 528                 struct clk      *clk = clock_list[i];
 529
 530                 if (clk->mode == pmc_sys_mode)
 531                         state = (scsr & clk->pmc_mask) ? "on" : "off";
 532                 else if (clk->mode == pmc_periph_mode)
 533                         state = (pcsr & clk->pmc_mask) ? "on" : "off";
 534                 else if (clk->pmc_mask)
 535                         state = (sr & clk->pmc_mask) ? "on" : "off";
 536                 else if (clk == &clk32k || clk == &main_clk)
 537                         state = "on";
 538                 else
 539                         state = "";
 540
 541                 seq_printf(s, "%-10s users=%2d %-3s %9ld Hz %s\n",
 542                         clk->name, clk->users, state, clk_get_rate(clk),
 543                         clk->parent ? clk->parent->name : "");
 544         }
 545         return 0;
 546 }
 547
 548 static int at91_clk_open(struct inode *inode, struct file *file)
 549 {
 550         return single_open(file, at91_clk_show, NULL);
 551 }
 552
 553 static struct file_operations at91_clk_operations = {
 554         .open           = at91_clk_open,
 555         .read           = seq_read,
 556         .llseek         = seq_lseek,
 557         .release        = single_release,
 558 };
 559
 560 static int __init at91_clk_debugfs_init(void)
 561 {
 562         /* /sys/kernel/debug/at91_clk */
 563         (void) debugfs_create_file("at91_clk", S_IFREG | S_IRUGO, NULL, NULL, &at91_clk_operations);
 564
 565         return 0;
 566 }
 567 postcore_initcall(at91_clk_debugfs_init);
 568
 569 #endif
 570
 571 /*------------------------------------------------------------------------*/
 572
 573 static u32 __init at91_pll_rate(struct clk *pll, u32 freq, u32 reg)
 574 {
 575         unsigned mul, div;
 576
 577         div = reg & 0xff;
 578         mul = (reg >> 16) & 0x7ff;
 579         if (div && mul) {
 580                 freq /= div;
 581                 freq *= mul + 1;
 582         } else
 583                 freq = 0;
 584
 585         return freq;
 586 }
 587
 588 static u32 __init at91_usb_rate(struct clk *pll, u32 freq, u32 reg)
 589 {
 590         if (pll == &pllb && (reg & AT91_PMC_USB96M))
 591                 return freq / 2;
 592         else
 593                 return freq;
 594 }
 595
 596 static unsigned __init at91_pll_calc(unsigned main_freq, unsigned out_freq)
 597 {
 598         unsigned i, div = 0, mul = 0, diff = 1 << 30;
 599         unsigned ret = (out_freq > 155000000) ? 0xbe00 : 0x3e00;
 600
 601         /* PLL output max 240 MHz (or 180 MHz per errata) */
 602         if (out_freq > 240000000)
 603                 goto fail;
 604
 605         for (i = 1; i < 256; i++) {
 606                 int diff1;
 607                 unsigned input, mul1;
 608
 609                 /*
 610                  * PLL input between 1MHz and 32MHz per spec, but lower
 611                  * frequences seem necessary in some cases so allow 100K.
 612                  */
 613                 input = main_freq / i;
 614                 if (input < 100000)
 615                         continue;
 616                 if (input > 32000000)
 617                         continue;
 618
 619                 mul1 = out_freq / input;
 620                 if (mul1 > 2048)
 621                         continue;
 622                 if (mul1 < 2)
 623                         goto fail;
 624
 625                 diff1 = out_freq - input * mul1;
 626                 if (diff1 < 0)
 627                         diff1 = -diff1;
 628                 if (diff > diff1) {
 629                         diff = diff1;
 630                         div = i;
 631                         mul = mul1;
 632                         if (diff == 0)
 633                                 break;
 634                 }
 635         }
 636         if (i == 256 && diff > (out_freq >> 5))
 637                 goto fail;
 638         return ret | ((mul - 1) << 16) | div;
 639 fail:
 640         return 0;
 641 }
 642
 643
 644 /*
 645  * Several unused clocks may be active.  Turn them off.
 646  */
 647 static void at91_periphclk_reset(void)
 648 {
 649         unsigned long reg;
 650         int i;
 651
 652         reg = at91_sys_read(AT91_PMC_PCSR);
 653
 654         for (i = 0; i < ARRAY_SIZE(clock_list); i++) {
 655                 struct clk      *clk = clock_list[i];
 656
 657                 if (clk->mode != pmc_periph_mode)
 658                         continue;
 659
 660                 if (clk->users > 0)
 661                         reg &= ~clk->pmc_mask;
 662         }
 663
 664         at91_sys_write(AT91_PMC_PCDR, reg);
 665 }
 666
 667 int __init at91_clock_init(unsigned long main_clock)
 668 {
 669         unsigned tmp, freq, mckr;
 670
 671         spin_lock_init(&clk_lock);
 672
 673         /*
 674          * When the bootloader initialized the main oscillator correctly,
 675          * there's no problem using the cycle counter.  But if it didn't,
 676          * or when using oscillator bypass mode, we must be told the speed
 677          * of the main clock.
 678          */
 679         if (!main_clock) {
 680                 do {
 681                         tmp = at91_sys_read(AT91_CKGR_MCFR);
 682                 } while (!(tmp & AT91_PMC_MAINRDY));
 683                 main_clock = (tmp & AT91_PMC_MAINF) * (AT91_SLOW_CLOCK / 16);
 684         }
 685         main_clk.rate_hz = main_clock;
 686
 687         /* report if PLLA is more than mildly overclocked */
 688         plla.rate_hz = at91_pll_rate(&plla, main_clock, at91_sys_read(AT91_CKGR_PLLAR));
 689         if (plla.rate_hz > 209000000)
 690                 pr_info("Clocks: PLLA overclocked, %ld MHz\n", plla.rate_hz / 1000000);
 691
 692         /*
 693          * USB clock init:  choose 48 MHz PLLB value, turn all clocks off,
 694          * disable 48MHz clock during usb peripheral suspend.
 695          *
 696          * REVISIT:  assumes MCK doesn't derive from PLLB!
 697          */
 698         at91_pllb_usb_init = at91_pll_calc(main_clock, 48000000 * 2) | AT91_PMC_USB96M;
 699         pllb.rate_hz = at91_pll_rate(&pllb, main_clock, at91_pllb_usb_init);
 700         at91_sys_write(AT91_PMC_SCDR, AT91_PMC_UHP | AT91_PMC_UDP);
 701         at91_sys_write(AT91_CKGR_PLLBR, 0);
 702         at91_sys_write(AT91_PMC_SCER, AT91_PMC_MCKUDP);
 703
 704         udpck.rate_hz = at91_usb_rate(&pllb, pllb.rate_hz, at91_pllb_usb_init);
 705         uhpck.rate_hz = at91_usb_rate(&pllb, pllb.rate_hz, at91_pllb_usb_init);
 706
 707         /*
 708          * MCK and CPU derive from one of those primary clocks.
 709          * For now, assume this parentage won't change.
 710          */
 711         mckr = at91_sys_read(AT91_PMC_MCKR);
 712         mck.parent = clock_list[mckr & AT91_PMC_CSS];
 713         freq = mck.parent->rate_hz;
 714         freq /= (1 << ((mckr >> 2) & 3));               /* prescale */
 715         mck.rate_hz = freq / (1 + ((mckr >> 8) & 3));   /* mdiv */
 716
 717         /* MCK and CPU clock are "always on" */
 718         clk_enable(&mck);
 719
 720         printk("Clocks: CPU %u MHz, master %u MHz, main %u.%03u MHz\n",
 721                 freq / 1000000, (unsigned) mck.rate_hz / 1000000,
 722                 (unsigned) main_clock / 1000000,
 723                 ((unsigned) main_clock % 1000000) / 1000);
 724
 725 #ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
 726         /* establish PCK0..PCK3 parentage */
 727         for (tmp = 0; tmp < ARRAY_SIZE(clock_list); tmp++) {
 728                 struct clk      *clk = clock_list[tmp], *parent;
 729                 u32             pckr;
 730
 731                 if (!clk->programmable)
 732                         continue;
 733
 734                 pckr = at91_sys_read(AT91_PMC_PCKR(clk->id));
 735                 parent = clock_list[pckr & AT91_PMC_CSS];
 736                 clk->parent = parent;
 737                 clk->rate_hz = parent->rate_hz / (1 << ((pckr >> 2) & 3));
 738
 739                 if (clk->users == 0) {
 740                         /* not being used, so switch it off */
 741                         at91_sys_write(AT91_PMC_SCDR, clk->pmc_mask);
 742                 }
 743         }
 744 #else
 745         /* disable all programmable clocks */
 746         at91_sys_write(AT91_PMC_SCDR, AT91_PMC_PCK0 | AT91_PMC_PCK1 | AT91_PMC_PCK2 | AT91_PMC_PCK3);
 747 #endif
 748
 749         /* enable the PIO clocks */
 750         clk_enable(&pioA_clk);
 751         clk_enable(&pioB_clk);
 752         clk_enable(&pioC_clk);
 753         clk_enable(&pioD_clk);
 754
 755         /* disable all other unused peripheral clocks */
 756         at91_periphclk_reset();
 757
 758         return 0;
 759 }