arch/powerpc/platforms/powermac/cpufreq_32.c

   1 /*
   2  *  Copyright (C) 2002 - 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>
   3  *  Copyright (C) 2004        John Steele Scott <toojays@toojays.net>
   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  * TODO: Need a big cleanup here. Basically, we need to have different
  10  * cpufreq_driver structures for the different type of HW instead of the
  11  * current mess. We also need to better deal with the detection of the
  12  * type of machine.
  13  *
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/types.h>
  18 #include <linux/errno.h>
  19 #include <linux/kernel.h>
  20 #include <linux/delay.h>
  21 #include <linux/sched.h>
  22 #include <linux/adb.h>
  23 #include <linux/pmu.h>
  24 #include <linux/cpufreq.h>
  25 #include <linux/init.h>
  26 #include <linux/sysdev.h>
  27 #include <linux/hardirq.h>
  28 #include <asm/prom.h>
  29 #include <asm/machdep.h>
  30 #include <asm/irq.h>
  31 #include <asm/pmac_feature.h>
  32 #include <asm/mmu_context.h>
  33 #include <asm/sections.h>
  34 #include <asm/cputable.h>
  35 #include <asm/time.h>
  36 #include <asm/system.h>
  37 #include <asm/mpic.h>
  38 #include <asm/keylargo.h>
  39
  40 /* WARNING !!! This will cause calibrate_delay() to be called,
  41  * but this is an __init function ! So you MUST go edit
  42  * init/main.c to make it non-init before enabling DEBUG_FREQ
  43  */
  44 #undef DEBUG_FREQ
  45
  46 extern void low_choose_7447a_dfs(int dfs);
  47 extern void low_choose_750fx_pll(int pll);
  48 extern void low_sleep_handler(void);
  49
  50 /*
  51  * Currently, PowerMac cpufreq supports only high & low frequencies
  52  * that are set by the firmware
  53  */
  54 static unsigned int low_freq;
  55 static unsigned int hi_freq;
  56 static unsigned int cur_freq;
  57 static unsigned int sleep_freq;
  58
  59 /*
  60  * Different models uses different mechanisms to switch the frequency
  61  */
  62 static int (*set_speed_proc)(int low_speed);
  63 static unsigned int (*get_speed_proc)(void);
  64
  65 /*
  66  * Some definitions used by the various speedprocs
  67  */
  68 static u32 voltage_gpio;
  69 static u32 frequency_gpio;
  70 static u32 slew_done_gpio;
  71 static int no_schedule;
  72 static int has_cpu_l2lve;
  73 static int is_pmu_based;
  74
  75 /* There are only two frequency states for each processor. Values
  76  * are in kHz for the time being.
  77  */
  78 #define CPUFREQ_HIGH                  0
  79 #define CPUFREQ_LOW                   1
  80
  81 static struct cpufreq_frequency_table pmac_cpu_freqs[] = {
  82         {CPUFREQ_HIGH,          0},
  83         {CPUFREQ_LOW,           0},
  84         {0,                     CPUFREQ_TABLE_END},
  85 };
  86
  87 static struct freq_attr* pmac_cpu_freqs_attr[] = {
  88         &cpufreq_freq_attr_scaling_available_freqs,
  89         NULL,
  90 };
  91
  92 static inline void local_delay(unsigned long ms)
  93 {
  94         if (no_schedule)
  95                 mdelay(ms);
  96         else
  97                 msleep(ms);
  98 }
  99
 100 #ifdef DEBUG_FREQ
 101 static inline void debug_calc_bogomips(void)
 102 {
 103         /* This will cause a recalc of bogomips and display the
 104          * result. We backup/restore the value to avoid affecting the
 105          * core cpufreq framework's own calculation.
 106          */
 107         unsigned long save_lpj = loops_per_jiffy;
 108         calibrate_delay();
 109         loops_per_jiffy = save_lpj;
 110 }
 111 #endif /* DEBUG_FREQ */
 112
 113 /* Switch CPU speed under 750FX CPU control
 114  */
 115 static int cpu_750fx_cpu_speed(int low_speed)
 116 {
 117         u32 hid2;
 118
 119         if (low_speed == 0) {
 120                 /* ramping up, set voltage first */
 121                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
 122                 /* Make sure we sleep for at least 1ms */
 123                 local_delay(10);
 124
 125                 /* tweak L2 for high voltage */
 126                 if (has_cpu_l2lve) {
 127                         hid2 = mfspr(SPRN_HID2);
 128                         hid2 &= ~0x2000;
 129                         mtspr(SPRN_HID2, hid2);
 130                 }
 131         }
 132 #ifdef CONFIG_6xx
 133         low_choose_750fx_pll(low_speed);
 134 #endif
 135         if (low_speed == 1) {
 136                 /* tweak L2 for low voltage */
 137                 if (has_cpu_l2lve) {
 138                         hid2 = mfspr(SPRN_HID2);
 139                         hid2 |= 0x2000;
 140                         mtspr(SPRN_HID2, hid2);
 141                 }
 142
 143                 /* ramping down, set voltage last */
 144                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
 145                 local_delay(10);
 146         }
 147
 148         return 0;
 149 }
 150
 151 static unsigned int cpu_750fx_get_cpu_speed(void)
 152 {
 153         if (mfspr(SPRN_HID1) & HID1_PS)
 154                 return low_freq;
 155         else
 156                 return hi_freq;
 157 }
 158
 159 /* Switch CPU speed using DFS */
 160 static int dfs_set_cpu_speed(int low_speed)
 161 {
 162         if (low_speed == 0) {
 163                 /* ramping up, set voltage first */
 164                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
 165                 /* Make sure we sleep for at least 1ms */
 166                 local_delay(1);
 167         }
 168
 169         /* set frequency */
 170 #ifdef CONFIG_6xx
 171         low_choose_7447a_dfs(low_speed);
 172 #endif
 173         udelay(100);
 174
 175         if (low_speed == 1) {
 176                 /* ramping down, set voltage last */
 177                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
 178                 local_delay(1);
 179         }
 180
 181         return 0;
 182 }
 183
 184 static unsigned int dfs_get_cpu_speed(void)
 185 {
 186         if (mfspr(SPRN_HID1) & HID1_DFS)
 187                 return low_freq;
 188         else
 189                 return hi_freq;
 190 }
 191
 192
 193 /* Switch CPU speed using slewing GPIOs
 194  */
 195 static int gpios_set_cpu_speed(int low_speed)
 196 {
 197         int gpio, timeout = 0;
 198
 199         /* If ramping up, set voltage first */
 200         if (low_speed == 0) {
 201                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
 202                 /* Delay is way too big but it's ok, we schedule */
 203                 local_delay(10);
 204         }
 205
 206         /* Set frequency */
 207         gpio =  pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, frequency_gpio, 0);
 208         if (low_speed == ((gpio & 0x01) == 0))
 209                 goto skip;
 210
 211         pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, frequency_gpio,
 212                           low_speed ? 0x04 : 0x05);
 213         udelay(200);
 214         do {
 215                 if (++timeout > 100)
 216                         break;
 217                 local_delay(1);
 218                 gpio = pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, slew_done_gpio, 0);
 219         } while((gpio & 0x02) == 0);
 220  skip:
 221         /* If ramping down, set voltage last */
 222         if (low_speed == 1) {
 223                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
 224                 /* Delay is way too big but it's ok, we schedule */
 225                 local_delay(10);
 226         }
 227
 228 #ifdef DEBUG_FREQ
 229         debug_calc_bogomips();
 230 #endif
 231
 232         return 0;
 233 }
 234
 235 /* Switch CPU speed under PMU control
 236  */
 237 static int pmu_set_cpu_speed(int low_speed)
 238 {
 239         struct adb_request req;
 240         unsigned long save_l2cr;
 241         unsigned long save_l3cr;
 242         unsigned int pic_prio;
 243         unsigned long flags;
 244
 245         preempt_disable();
 246
 247 #ifdef DEBUG_FREQ
 248         printk(KERN_DEBUG "HID1, before: %x\n", mfspr(SPRN_HID1));
 249 #endif
 250         pmu_suspend();
 251
 252         /* Disable all interrupt sources on openpic */
 253         pic_prio = mpic_cpu_get_priority();
 254         mpic_cpu_set_priority(0xf);
 255
 256         /* Make sure the decrementer won't interrupt us */
 257         asm volatile("mtdec %0" : : "r" (0x7fffffff));
 258         /* Make sure any pending DEC interrupt occurring while we did
 259          * the above didn't re-enable the DEC */
 260         mb();
 261         asm volatile("mtdec %0" : : "r" (0x7fffffff));
 262
 263         /* We can now disable MSR_EE */
 264         local_irq_save(flags);
 265
 266         /* Giveup the FPU & vec */
 267         enable_kernel_fp();
 268
 269 #ifdef CONFIG_ALTIVEC
 270         if (cpu_has_feature(CPU_FTR_ALTIVEC))
 271                 enable_kernel_altivec();
 272 #endif /* CONFIG_ALTIVEC */
 273
 274         /* Save & disable L2 and L3 caches */
 275         save_l3cr = _get_L3CR();        /* (returns -1 if not available) */
 276         save_l2cr = _get_L2CR();        /* (returns -1 if not available) */
 277
 278         /* Send the new speed command. My assumption is that this command
 279          * will cause PLL_CFG[0..3] to be changed next time CPU goes to sleep
 280          */
 281         pmu_request(&req, NULL, 6, PMU_CPU_SPEED, 'W', 'O', 'O', 'F', low_speed);
 282         while (!req.complete)
 283                 pmu_poll();
 284
 285         /* Prepare the northbridge for the speed transition */
 286         pmac_call_feature(PMAC_FTR_SLEEP_STATE,NULL,1,1);
 287
 288         /* Call low level code to backup CPU state and recover from
 289          * hardware reset
 290          */
 291         low_sleep_handler();
 292
 293         /* Restore the northbridge */
 294         pmac_call_feature(PMAC_FTR_SLEEP_STATE,NULL,1,0);
 295
 296         /* Restore L2 cache */
 297         if (save_l2cr != 0xffffffff && (save_l2cr & L2CR_L2E) != 0)
 298                 _set_L2CR(save_l2cr);
 299         /* Restore L3 cache */
 300         if (save_l3cr != 0xffffffff && (save_l3cr & L3CR_L3E) != 0)
 301                 _set_L3CR(save_l3cr);
 302
 303         /* Restore userland MMU context */
 304         switch_mmu_context(NULL, current->active_mm);
 305
 306 #ifdef DEBUG_FREQ
 307         printk(KERN_DEBUG "HID1, after: %x\n", mfspr(SPRN_HID1));
 308 #endif
 309
 310         /* Restore low level PMU operations */
 311         pmu_unlock();
 312
 313         /*
 314          * Restore decrementer; we'll take a decrementer interrupt
 315          * as soon as interrupts are re-enabled and the generic
 316          * clockevents code will reprogram it with the right value.
 317          */
 318         set_dec(1);
 319
 320         /* Restore interrupts */
 321         mpic_cpu_set_priority(pic_prio);
 322
 323         /* Let interrupts flow again ... */
 324         local_irq_restore(flags);
 325
 326 #ifdef DEBUG_FREQ
 327         debug_calc_bogomips();
 328 #endif
 329
 330         pmu_resume();
 331
 332         preempt_enable();
 333
 334         return 0;
 335 }
 336
 337 static int do_set_cpu_speed(int speed_mode, int notify)
 338 {
 339         struct cpufreq_freqs freqs;
 340         unsigned long l3cr;
 341         static unsigned long prev_l3cr;
 342
 343         freqs.old = cur_freq;
 344         freqs.new = (speed_mode == CPUFREQ_HIGH) ? hi_freq : low_freq;
 345         freqs.cpu = smp_processor_id();
 346
 347         if (freqs.old == freqs.new)
 348                 return 0;
 349
 350         if (notify)
 351                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 352         if (speed_mode == CPUFREQ_LOW &&
 353             cpu_has_feature(CPU_FTR_L3CR)) {
 354                 l3cr = _get_L3CR();
 355                 if (l3cr & L3CR_L3E) {
 356                         prev_l3cr = l3cr;
 357                         _set_L3CR(0);
 358                 }
 359         }
 360         set_speed_proc(speed_mode == CPUFREQ_LOW);
 361         if (speed_mode == CPUFREQ_HIGH &&
 362             cpu_has_feature(CPU_FTR_L3CR)) {
 363                 l3cr = _get_L3CR();
 364                 if ((prev_l3cr & L3CR_L3E) && l3cr != prev_l3cr)
 365                         _set_L3CR(prev_l3cr);
 366         }
 367         if (notify)
 368                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 369         cur_freq = (speed_mode == CPUFREQ_HIGH) ? hi_freq : low_freq;
 370
 371         return 0;
 372 }
 373
 374 static unsigned int pmac_cpufreq_get_speed(unsigned int cpu)
 375 {
 376         return cur_freq;
 377 }
 378
 379 static int pmac_cpufreq_verify(struct cpufreq_policy *policy)
 380 {
 381         return cpufreq_frequency_table_verify(policy, pmac_cpu_freqs);
 382 }
 383
 384 static int pmac_cpufreq_target( struct cpufreq_policy *policy,
 385                                         unsigned int target_freq,
 386                                         unsigned int relation)
 387 {
 388         unsigned int    newstate = 0;
 389         int             rc;
 390
 391         if (cpufreq_frequency_table_target(policy, pmac_cpu_freqs,
 392                         target_freq, relation, &newstate))
 393                 return -EINVAL;
 394
 395         rc = do_set_cpu_speed(newstate, 1);
 396
 397         ppc_proc_freq = cur_freq * 1000ul;
 398         return rc;
 399 }
 400
 401 static int pmac_cpufreq_cpu_init(struct cpufreq_policy *policy)
 402 {
 403         if (policy->cpu != 0)
 404                 return -ENODEV;
 405
 406         policy->cpuinfo.transition_latency      = CPUFREQ_ETERNAL;
 407         policy->cur = cur_freq;
 408
 409         cpufreq_frequency_table_get_attr(pmac_cpu_freqs, policy->cpu);
 410         return cpufreq_frequency_table_cpuinfo(policy, pmac_cpu_freqs);
 411 }
 412
 413 static u32 read_gpio(struct device_node *np)
 414 {
 415         const u32 *reg = of_get_property(np, "reg", NULL);
 416         u32 offset;
 417
 418         if (reg == NULL)
 419                 return 0;
 420         /* That works for all keylargos but shall be fixed properly
 421          * some day... The problem is that it seems we can't rely
 422          * on the "reg" property of the GPIO nodes, they are either
 423          * relative to the base of KeyLargo or to the base of the
 424          * GPIO space, and the device-tree doesn't help.
 425          */
 426         offset = *reg;
 427         if (offset < KEYLARGO_GPIO_LEVELS0)
 428                 offset += KEYLARGO_GPIO_LEVELS0;
 429         return offset;
 430 }
 431
 432 static int pmac_cpufreq_suspend(struct cpufreq_policy *policy, pm_message_t pmsg)
 433 {
 434         /* Ok, this could be made a bit smarter, but let's be robust for now. We
 435          * always force a speed change to high speed before sleep, to make sure
 436          * we have appropriate voltage and/or bus speed for the wakeup process,
 437          * and to make sure our loops_per_jiffies are "good enough", that is will
 438          * not cause too short delays if we sleep in low speed and wake in high
 439          * speed..
 440          */
 441         no_schedule = 1;
 442         sleep_freq = cur_freq;
 443         if (cur_freq == low_freq && !is_pmu_based)
 444                 do_set_cpu_speed(CPUFREQ_HIGH, 0);
 445         return 0;
 446 }
 447
 448 static int pmac_cpufreq_resume(struct cpufreq_policy *policy)
 449 {
 450         /* If we resume, first check if we have a get() function */
 451         if (get_speed_proc)
 452                 cur_freq = get_speed_proc();
 453         else
 454                 cur_freq = 0;
 455
 456         /* We don't, hrm... we don't really know our speed here, best
 457          * is that we force a switch to whatever it was, which is
 458          * probably high speed due to our suspend() routine
 459          */
 460         do_set_cpu_speed(sleep_freq == low_freq ?
 461                          CPUFREQ_LOW : CPUFREQ_HIGH, 0);
 462
 463         ppc_proc_freq = cur_freq * 1000ul;
 464
 465         no_schedule = 0;
 466         return 0;
 467 }
 468
 469 static struct cpufreq_driver pmac_cpufreq_driver = {
 470         .verify         = pmac_cpufreq_verify,
 471         .target         = pmac_cpufreq_target,
 472         .get            = pmac_cpufreq_get_speed,
 473         .init           = pmac_cpufreq_cpu_init,
 474         .suspend        = pmac_cpufreq_suspend,
 475         .resume         = pmac_cpufreq_resume,
 476         .flags          = CPUFREQ_PM_NO_WARN,
 477         .attr           = pmac_cpu_freqs_attr,
 478         .name           = "powermac",
 479         .owner          = THIS_MODULE,
 480 };
 481
 482
 483 static int pmac_cpufreq_init_MacRISC3(struct device_node *cpunode)
 484 {
 485         struct device_node *volt_gpio_np = of_find_node_by_name(NULL,
 486                                                                 "voltage-gpio");
 487         struct device_node *freq_gpio_np = of_find_node_by_name(NULL,
 488                                                                 "frequency-gpio");
 489         struct device_node *slew_done_gpio_np = of_find_node_by_name(NULL,
 490                                                                      "slewing-done");
 491         const u32 *value;
 492
 493         /*
 494          * Check to see if it's GPIO driven or PMU only
 495          *
 496          * The way we extract the GPIO address is slightly hackish, but it
 497          * works well enough for now. We need to abstract the whole GPIO
 498          * stuff sooner or later anyway
 499          */
 500
 501         if (volt_gpio_np)
 502                 voltage_gpio = read_gpio(volt_gpio_np);
 503         if (freq_gpio_np)
 504                 frequency_gpio = read_gpio(freq_gpio_np);
 505         if (slew_done_gpio_np)
 506                 slew_done_gpio = read_gpio(slew_done_gpio_np);
 507
 508         /* If we use the frequency GPIOs, calculate the min/max speeds based
 509          * on the bus frequencies
 510          */
 511         if (frequency_gpio && slew_done_gpio) {
 512                 int lenp, rc;
 513                 const u32 *freqs, *ratio;
 514
 515                 freqs = of_get_property(cpunode, "bus-frequencies", &lenp);
 516                 lenp /= sizeof(u32);
 517                 if (freqs == NULL || lenp != 2) {
 518                         printk(KERN_ERR "cpufreq: bus-frequencies incorrect or missing\n");
 519                         return 1;
 520                 }
 521                 ratio = of_get_property(cpunode, "processor-to-bus-ratio*2",
 522                                                 NULL);
 523                 if (ratio == NULL) {
 524                         printk(KERN_ERR "cpufreq: processor-to-bus-ratio*2 missing\n");
 525                         return 1;
 526                 }
 527
 528                 /* Get the min/max bus frequencies */
 529                 low_freq = min(freqs[0], freqs[1]);
 530                 hi_freq = max(freqs[0], freqs[1]);
 531
 532                 /* Grrrr.. It _seems_ that the device-tree is lying on the low bus
 533                  * frequency, it claims it to be around 84Mhz on some models while
 534                  * it appears to be approx. 101Mhz on all. Let's hack around here...
 535                  * fortunately, we don't need to be too precise
 536                  */
 537                 if (low_freq < 98000000)
 538                         low_freq = 101000000;
 539
 540                 /* Convert those to CPU core clocks */
 541                 low_freq = (low_freq * (*ratio)) / 2000;
 542                 hi_freq = (hi_freq * (*ratio)) / 2000;
 543
 544                 /* Now we get the frequencies, we read the GPIO to see what is out current
 545                  * speed
 546                  */
 547                 rc = pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, frequency_gpio, 0);
 548                 cur_freq = (rc & 0x01) ? hi_freq : low_freq;
 549
 550                 set_speed_proc = gpios_set_cpu_speed;
 551                 return 1;
 552         }
 553
 554         /* If we use the PMU, look for the min & max frequencies in the
 555          * device-tree
 556          */
 557         value = of_get_property(cpunode, "min-clock-frequency", NULL);
 558         if (!value)
 559                 return 1;
 560         low_freq = (*value) / 1000;
 561         /* The PowerBook G4 12" (PowerBook6,1) has an error in the device-tree
 562          * here */
 563         if (low_freq < 100000)
 564                 low_freq *= 10;
 565
 566         value = of_get_property(cpunode, "max-clock-frequency", NULL);
 567         if (!value)
 568                 return 1;
 569         hi_freq = (*value) / 1000;
 570         set_speed_proc = pmu_set_cpu_speed;
 571         is_pmu_based = 1;
 572
 573         return 0;
 574 }
 575
 576 static int pmac_cpufreq_init_7447A(struct device_node *cpunode)
 577 {
 578         struct device_node *volt_gpio_np;
 579
 580         if (of_get_property(cpunode, "dynamic-power-step", NULL) == NULL)
 581                 return 1;
 582
 583         volt_gpio_np = of_find_node_by_name(NULL, "cpu-vcore-select");
 584         if (volt_gpio_np)
 585                 voltage_gpio = read_gpio(volt_gpio_np);
 586         if (!voltage_gpio){
 587                 printk(KERN_ERR "cpufreq: missing cpu-vcore-select gpio\n");
 588                 return 1;
 589         }
 590
 591         /* OF only reports the high frequency */
 592         hi_freq = cur_freq;
 593         low_freq = cur_freq/2;
 594
 595         /* Read actual frequency from CPU */
 596         cur_freq = dfs_get_cpu_speed();
 597         set_speed_proc = dfs_set_cpu_speed;
 598         get_speed_proc = dfs_get_cpu_speed;
 599
 600         return 0;
 601 }
 602
 603 static int pmac_cpufreq_init_750FX(struct device_node *cpunode)
 604 {
 605         struct device_node *volt_gpio_np;
 606         u32 pvr;
 607         const u32 *value;
 608
 609         if (of_get_property(cpunode, "dynamic-power-step", NULL) == NULL)
 610                 return 1;
 611
 612         hi_freq = cur_freq;
 613         value = of_get_property(cpunode, "reduced-clock-frequency", NULL);
 614         if (!value)
 615                 return 1;
 616         low_freq = (*value) / 1000;
 617
 618         volt_gpio_np = of_find_node_by_name(NULL, "cpu-vcore-select");
 619         if (volt_gpio_np)
 620                 voltage_gpio = read_gpio(volt_gpio_np);
 621
 622         pvr = mfspr(SPRN_PVR);
 623         has_cpu_l2lve = !((pvr & 0xf00) == 0x100);
 624
 625         set_speed_proc = cpu_750fx_cpu_speed;
 626         get_speed_proc = cpu_750fx_get_cpu_speed;
 627         cur_freq = cpu_750fx_get_cpu_speed();
 628
 629         return 0;
 630 }
 631
 632 /* Currently, we support the following machines:
 633  *
 634  *  - Titanium PowerBook 1Ghz (PMU based, 667Mhz & 1Ghz)
 635  *  - Titanium PowerBook 800 (PMU based, 667Mhz & 800Mhz)
 636  *  - Titanium PowerBook 400 (PMU based, 300Mhz & 400Mhz)
 637  *  - Titanium PowerBook 500 (PMU based, 300Mhz & 500Mhz)
 638  *  - iBook2 500/600 (PMU based, 400Mhz & 500/600Mhz)
 639  *  - iBook2 700 (CPU based, 400Mhz & 700Mhz, support low voltage)
 640  *  - Recent MacRISC3 laptops
 641  *  - All new machines with 7447A CPUs
 642  */
 643 static int __init pmac_cpufreq_setup(void)
 644 {
 645         struct device_node      *cpunode;
 646         const u32               *value;
 647
 648         if (strstr(cmd_line, "nocpufreq"))
 649                 return 0;
 650
 651         /* Assume only one CPU */
 652         cpunode = of_find_node_by_type(NULL, "cpu");
 653         if (!cpunode)
 654                 goto out;
 655
 656         /* Get current cpu clock freq */
 657         value = of_get_property(cpunode, "clock-frequency", NULL);
 658         if (!value)
 659                 goto out;
 660         cur_freq = (*value) / 1000;
 661
 662         /*  Check for 7447A based MacRISC3 */
 663         if (of_machine_is_compatible("MacRISC3") &&
 664             of_get_property(cpunode, "dynamic-power-step", NULL) &&
 665             PVR_VER(mfspr(SPRN_PVR)) == 0x8003) {
 666                 pmac_cpufreq_init_7447A(cpunode);
 667         /* Check for other MacRISC3 machines */
 668         } else if (of_machine_is_compatible("PowerBook3,4") ||
 669                    of_machine_is_compatible("PowerBook3,5") ||
 670                    of_machine_is_compatible("MacRISC3")) {
 671                 pmac_cpufreq_init_MacRISC3(cpunode);
 672         /* Else check for iBook2 500/600 */
 673         } else if (of_machine_is_compatible("PowerBook4,1")) {
 674                 hi_freq = cur_freq;
 675                 low_freq = 400000;
 676                 set_speed_proc = pmu_set_cpu_speed;
 677                 is_pmu_based = 1;
 678         }
 679         /* Else check for TiPb 550 */
 680         else if (of_machine_is_compatible("PowerBook3,3") && cur_freq == 550000) {
 681                 hi_freq = cur_freq;
 682                 low_freq = 500000;
 683                 set_speed_proc = pmu_set_cpu_speed;
 684                 is_pmu_based = 1;
 685         }
 686         /* Else check for TiPb 400 & 500 */
 687         else if (of_machine_is_compatible("PowerBook3,2")) {
 688                 /* We only know about the 400 MHz and the 500Mhz model
 689                  * they both have 300 MHz as low frequency
 690                  */
 691                 if (cur_freq < 350000 || cur_freq > 550000)
 692                         goto out;
 693                 hi_freq = cur_freq;
 694                 low_freq = 300000;
 695                 set_speed_proc = pmu_set_cpu_speed;
 696                 is_pmu_based = 1;
 697         }
 698         /* Else check for 750FX */
 699         else if (PVR_VER(mfspr(SPRN_PVR)) == 0x7000)
 700                 pmac_cpufreq_init_750FX(cpunode);
 701 out:
 702         of_node_put(cpunode);
 703         if (set_speed_proc == NULL)
 704                 return -ENODEV;
 705
 706         pmac_cpu_freqs[CPUFREQ_LOW].frequency = low_freq;
 707         pmac_cpu_freqs[CPUFREQ_HIGH].frequency = hi_freq;
 708         ppc_proc_freq = cur_freq * 1000ul;
 709
 710         printk(KERN_INFO "Registering PowerMac CPU frequency driver\n");
 711         printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Boot: %d Mhz\n",
 712                low_freq/1000, hi_freq/1000, cur_freq/1000);
 713
 714         return cpufreq_register_driver(&pmac_cpufreq_driver);
 715 }
 716
 717 module_init(pmac_cpufreq_setup);
 718