git.oblomov.eu Git - linux-2.6/blob - arch/powerpc/platforms/powermac/cpufreq_64.c

   1 /*
   2  *  Copyright (C) 2002 - 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>
   3  *  and                       Markus Demleitner <msdemlei@cl.uni-heidelberg.de>
   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  * This driver adds basic cpufreq support for SMU & 970FX based G5 Macs,
  10  * that is iMac G5 and latest single CPU desktop.
  11  */
  12
  13 #include <linux/config.h>
  14 #include <linux/module.h>
  15 #include <linux/types.h>
  16 #include <linux/errno.h>
  17 #include <linux/kernel.h>
  18 #include <linux/delay.h>
  19 #include <linux/sched.h>
  20 #include <linux/slab.h>
  21 #include <linux/cpufreq.h>
  22 #include <linux/init.h>
  23 #include <linux/completion.h>
  24 #include <asm/prom.h>
  25 #include <asm/machdep.h>
  26 #include <asm/irq.h>
  27 #include <asm/sections.h>
  28 #include <asm/cputable.h>
  29 #include <asm/time.h>
  30 #include <asm/smu.h>
  31 #include <asm/pmac_pfunc.h>
  32
  33 #undef DEBUG
  34
  35 #ifdef DEBUG
  36 #define DBG(fmt...) printk(fmt)
  37 #else
  38 #define DBG(fmt...)
  39 #endif
  40
  41 /* see 970FX user manual */
  42
  43 #define SCOM_PCR 0x0aa001                       /* PCR scom addr */
  44
  45 #define PCR_HILO_SELECT         0x80000000U     /* 1 = PCR, 0 = PCRH */
  46 #define PCR_SPEED_FULL          0x00000000U     /* 1:1 speed value */
  47 #define PCR_SPEED_HALF          0x00020000U     /* 1:2 speed value */
  48 #define PCR_SPEED_QUARTER       0x00040000U     /* 1:4 speed value */
  49 #define PCR_SPEED_MASK          0x000e0000U     /* speed mask */
  50 #define PCR_SPEED_SHIFT         17
  51 #define PCR_FREQ_REQ_VALID      0x00010000U     /* freq request valid */
  52 #define PCR_VOLT_REQ_VALID      0x00008000U     /* volt request valid */
  53 #define PCR_TARGET_TIME_MASK    0x00006000U     /* target time */
  54 #define PCR_STATLAT_MASK        0x00001f00U     /* STATLAT value */
  55 #define PCR_SNOOPLAT_MASK       0x000000f0U     /* SNOOPLAT value */
  56 #define PCR_SNOOPACC_MASK       0x0000000fU     /* SNOOPACC value */
  57
  58 #define SCOM_PSR 0x408001                       /* PSR scom addr */
  59 /* warning: PSR is a 64 bits register */
  60 #define PSR_CMD_RECEIVED        0x2000000000000000U   /* command received */
  61 #define PSR_CMD_COMPLETED       0x1000000000000000U   /* command completed */
  62 #define PSR_CUR_SPEED_MASK      0x0300000000000000U   /* current speed */
  63 #define PSR_CUR_SPEED_SHIFT     (56)
  64
  65 /*
  66  * The G5 only supports two frequencies (Quarter speed is not supported)
  67  */
  68 #define CPUFREQ_HIGH                  0
  69 #define CPUFREQ_LOW                   1
  70
  71 static struct cpufreq_frequency_table g5_cpu_freqs[] = {
  72         {CPUFREQ_HIGH,          0},
  73         {CPUFREQ_LOW,           0},
  74         {0,                     CPUFREQ_TABLE_END},
  75 };
  76
  77 static struct freq_attr* g5_cpu_freqs_attr[] = {
  78         &cpufreq_freq_attr_scaling_available_freqs,
  79         NULL,
  80 };
  81
  82 /* Power mode data is an array of the 32 bits PCR values to use for
  83  * the various frequencies, retreived from the device-tree
  84  */
  85 static u32 *g5_pmode_data;
  86 static int g5_pmode_max;
  87 static int g5_pmode_cur;
  88
  89 static void (*g5_switch_volt)(int speed_mode);
  90 static int (*g5_switch_freq)(int speed_mode);
  91 static int (*g5_query_freq)(void);
  92
  93 static DECLARE_MUTEX(g5_switch_mutex);
  94
  95
  96 static struct smu_sdbp_fvt *g5_fvt_table;       /* table of op. points */
  97 static int g5_fvt_count;                        /* number of op. points */
  98 static int g5_fvt_cur;                          /* current op. point */
  99
 100 /*
 101  * SMU based voltage switching for Neo2 platforms
 102  */
 103
 104 static void g5_smu_switch_volt(int speed_mode)
 105 {
 106         struct smu_simple_cmd   cmd;
 107
 108         DECLARE_COMPLETION(comp);
 109         smu_queue_simple(&cmd, SMU_CMD_POWER_COMMAND, 8, smu_done_complete,
 110                          &comp, 'V', 'S', 'L', 'E', 'W',
 111                          0xff, g5_fvt_cur+1, speed_mode);
 112         wait_for_completion(&comp);
 113 }
 114
 115 /*
 116  * Platform function based voltage/vdnap switching for Neo2
 117  */
 118
 119 static struct pmf_function *pfunc_set_vdnap0;
 120 static struct pmf_function *pfunc_vdnap0_complete;
 121
 122 static void g5_vdnap_switch_volt(int speed_mode)
 123 {
 124         struct pmf_args args;
 125         u32 slew, done = 0;
 126         unsigned long timeout;
 127
 128         slew = (speed_mode == CPUFREQ_LOW) ? 1 : 0;
 129         args.count = 1;
 130         args.u[0].p = &slew;
 131
 132         pmf_call_one(pfunc_set_vdnap0, &args);
 133
 134         /* It's an irq GPIO so we should be able to just block here,
 135          * I'll do that later after I've properly tested the IRQ code for
 136          * platform functions
 137          */
 138         timeout = jiffies + HZ/10;
 139         while(!time_after(jiffies, timeout)) {
 140                 args.count = 1;
 141                 args.u[0].p = &done;
 142                 pmf_call_one(pfunc_vdnap0_complete, &args);
 143                 if (done)
 144                         break;
 145                 msleep(1);
 146         }
 147         if (done == 0)
 148                 printk(KERN_WARNING "cpufreq: Timeout in clock slewing !\n");
 149 }
 150
 151
 152 /*
 153  * SCOM based frequency switching for 970FX rev3
 154  */
 155 static int g5_scom_switch_freq(int speed_mode)
 156 {
 157         unsigned long flags;
 158         int to;
 159
 160         /* If frequency is going up, first ramp up the voltage */
 161         if (speed_mode < g5_pmode_cur)
 162                 g5_switch_volt(speed_mode);
 163
 164         local_irq_save(flags);
 165
 166         /* Clear PCR high */
 167         scom970_write(SCOM_PCR, 0);
 168         /* Clear PCR low */
 169         scom970_write(SCOM_PCR, PCR_HILO_SELECT | 0);
 170         /* Set PCR low */
 171         scom970_write(SCOM_PCR, PCR_HILO_SELECT |
 172                       g5_pmode_data[speed_mode]);
 173
 174         /* Wait for completion */
 175         for (to = 0; to < 10; to++) {
 176                 unsigned long psr = scom970_read(SCOM_PSR);
 177
 178                 if ((psr & PSR_CMD_RECEIVED) == 0 &&
 179                     (((psr >> PSR_CUR_SPEED_SHIFT) ^
 180                       (g5_pmode_data[speed_mode] >> PCR_SPEED_SHIFT)) & 0x3)
 181                     == 0)
 182                         break;
 183                 if (psr & PSR_CMD_COMPLETED)
 184                         break;
 185                 udelay(100);
 186         }
 187
 188         local_irq_restore(flags);
 189
 190         /* If frequency is going down, last ramp the voltage */
 191         if (speed_mode > g5_pmode_cur)
 192                 g5_switch_volt(speed_mode);
 193
 194         g5_pmode_cur = speed_mode;
 195         ppc_proc_freq = g5_cpu_freqs[speed_mode].frequency * 1000ul;
 196
 197         return 0;
 198 }
 199
 200 static int g5_scom_query_freq(void)
 201 {
 202         unsigned long psr = scom970_read(SCOM_PSR);
 203         int i;
 204
 205         for (i = 0; i <= g5_pmode_max; i++)
 206                 if ((((psr >> PSR_CUR_SPEED_SHIFT) ^
 207                       (g5_pmode_data[i] >> PCR_SPEED_SHIFT)) & 0x3) == 0)
 208                         break;
 209         return i;
 210 }
 211
 212 /*
 213  * Platform function based voltage switching for PowerMac7,2 & 7,3
 214  */
 215
 216 static struct pmf_function *pfunc_cpu0_volt_high;
 217 static struct pmf_function *pfunc_cpu0_volt_low;
 218 static struct pmf_function *pfunc_cpu1_volt_high;
 219 static struct pmf_function *pfunc_cpu1_volt_low;
 220
 221 static void g5_pfunc_switch_volt(int speed_mode)
 222 {
 223         if (speed_mode == CPUFREQ_HIGH) {
 224                 if (pfunc_cpu0_volt_high)
 225                         pmf_call_one(pfunc_cpu0_volt_high, NULL);
 226                 if (pfunc_cpu1_volt_high)
 227                         pmf_call_one(pfunc_cpu1_volt_high, NULL);
 228         } else {
 229                 if (pfunc_cpu0_volt_low)
 230                         pmf_call_one(pfunc_cpu0_volt_low, NULL);
 231                 if (pfunc_cpu1_volt_low)
 232                         pmf_call_one(pfunc_cpu1_volt_low, NULL);
 233         }
 234         msleep(10); /* should be faster , to fix */
 235 }
 236
 237 /*
 238  * Platform function based frequency switching for PowerMac7,2 & 7,3
 239  */
 240
 241 static struct pmf_function *pfunc_cpu_setfreq_high;
 242 static struct pmf_function *pfunc_cpu_setfreq_low;
 243 static struct pmf_function *pfunc_cpu_getfreq;
 244 static struct pmf_function *pfunc_slewing_done;;
 245
 246 static int g5_pfunc_switch_freq(int speed_mode)
 247 {
 248         struct pmf_args args;
 249         u32 done = 0;
 250         unsigned long timeout;
 251
 252         /* If frequency is going up, first ramp up the voltage */
 253         if (speed_mode < g5_pmode_cur)
 254                 g5_switch_volt(speed_mode);
 255
 256         /* Do it */
 257         if (speed_mode == CPUFREQ_HIGH)
 258                 pmf_call_one(pfunc_cpu_setfreq_high, NULL);
 259         else
 260                 pmf_call_one(pfunc_cpu_setfreq_low, NULL);
 261
 262         /* It's an irq GPIO so we should be able to just block here,
 263          * I'll do that later after I've properly tested the IRQ code for
 264          * platform functions
 265          */
 266         timeout = jiffies + HZ/10;
 267         while(!time_after(jiffies, timeout)) {
 268                 args.count = 1;
 269                 args.u[0].p = &done;
 270                 pmf_call_one(pfunc_slewing_done, &args);
 271                 if (done)
 272                         break;
 273                 msleep(1);
 274         }
 275         if (done == 0)
 276                 printk(KERN_WARNING "cpufreq: Timeout in clock slewing !\n");
 277
 278         /* If frequency is going down, last ramp the voltage */
 279         if (speed_mode > g5_pmode_cur)
 280                 g5_switch_volt(speed_mode);
 281
 282         g5_pmode_cur = speed_mode;
 283         ppc_proc_freq = g5_cpu_freqs[speed_mode].frequency * 1000ul;
 284
 285         return 0;
 286 }
 287
 288 static int g5_pfunc_query_freq(void)
 289 {
 290         struct pmf_args args;
 291         u32 val = 0;
 292
 293         args.count = 1;
 294         args.u[0].p = &val;
 295         pmf_call_one(pfunc_cpu_getfreq, &args);
 296         return val ? CPUFREQ_HIGH : CPUFREQ_LOW;
 297 }
 298
 299 /*
 300  * Fake voltage switching for platforms with missing support
 301  */
 302
 303 static void g5_dummy_switch_volt(int speed_mode)
 304 {
 305 }
 306
 307 /*
 308  * Common interface to the cpufreq core
 309  */
 310
 311 static int g5_cpufreq_verify(struct cpufreq_policy *policy)
 312 {
 313         return cpufreq_frequency_table_verify(policy, g5_cpu_freqs);
 314 }
 315
 316 static int g5_cpufreq_target(struct cpufreq_policy *policy,
 317         unsigned int target_freq, unsigned int relation)
 318 {
 319         unsigned int newstate = 0;
 320         struct cpufreq_freqs freqs;
 321         int rc;
 322
 323         if (cpufreq_frequency_table_target(policy, g5_cpu_freqs,
 324                         target_freq, relation, &newstate))
 325                 return -EINVAL;
 326
 327         if (g5_pmode_cur == newstate)
 328                 return 0;
 329
 330         down(&g5_switch_mutex);
 331
 332         freqs.old = g5_cpu_freqs[g5_pmode_cur].frequency;
 333         freqs.new = g5_cpu_freqs[newstate].frequency;
 334         freqs.cpu = 0;
 335
 336         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 337         rc = g5_switch_freq(newstate);
 338         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 339
 340         up(&g5_switch_mutex);
 341
 342         return rc;
 343 }
 344
 345 static unsigned int g5_cpufreq_get_speed(unsigned int cpu)
 346 {
 347         return g5_cpu_freqs[g5_pmode_cur].frequency;
 348 }
 349
 350 static int g5_cpufreq_cpu_init(struct cpufreq_policy *policy)
 351 {
 352         if (policy->cpu != 0)
 353                 return -ENODEV;
 354
 355         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 356         policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 357         policy->cur = g5_cpu_freqs[g5_query_freq()].frequency;
 358         policy->cpus = cpu_possible_map;
 359         cpufreq_frequency_table_get_attr(g5_cpu_freqs, policy->cpu);
 360
 361         return cpufreq_frequency_table_cpuinfo(policy,
 362                 g5_cpu_freqs);
 363 }
 364
 365
 366 static struct cpufreq_driver g5_cpufreq_driver = {
 367         .name           = "powermac",
 368         .owner          = THIS_MODULE,
 369         .flags          = CPUFREQ_CONST_LOOPS,
 370         .init           = g5_cpufreq_cpu_init,
 371         .verify         = g5_cpufreq_verify,
 372         .target         = g5_cpufreq_target,
 373         .get            = g5_cpufreq_get_speed,
 374         .attr           = g5_cpu_freqs_attr,
 375 };
 376
 377
 378 static int __init g5_neo2_cpufreq_init(struct device_node *cpus)
 379 {
 380         struct device_node *cpunode;
 381         unsigned int psize, ssize;
 382         unsigned long max_freq;
 383         char *freq_method, *volt_method;
 384         u32 *valp, pvr_hi;
 385         int use_volts_vdnap = 0;
 386         int use_volts_smu = 0;
 387         int rc = -ENODEV;
 388
 389         /* Check supported platforms */
 390         if (machine_is_compatible("PowerMac8,1") ||
 391             machine_is_compatible("PowerMac8,2") ||
 392             machine_is_compatible("PowerMac9,1"))
 393                 use_volts_smu = 1;
 394         else if (machine_is_compatible("PowerMac11,2"))
 395                 use_volts_vdnap = 1;
 396         else
 397                 return -ENODEV;
 398
 399         /* Get first CPU node */
 400         for (cpunode = NULL;
 401              (cpunode = of_get_next_child(cpus, cpunode)) != NULL;) {
 402                 u32 *reg =
 403                         (u32 *)get_property(cpunode, "reg", NULL);
 404                 if (reg == NULL || (*reg) != 0)
 405                         continue;
 406                 if (!strcmp(cpunode->type, "cpu"))
 407                         break;
 408         }
 409         if (cpunode == NULL) {
 410                 printk(KERN_ERR "cpufreq: Can't find any CPU 0 node\n");
 411                 return -ENODEV;
 412         }
 413
 414         /* Check 970FX for now */
 415         valp = (u32 *)get_property(cpunode, "cpu-version", NULL);
 416         if (!valp) {
 417                 DBG("No cpu-version property !\n");
 418                 goto bail_noprops;
 419         }
 420         pvr_hi = (*valp) >> 16;
 421         if (pvr_hi != 0x3c && pvr_hi != 0x44) {
 422                 printk(KERN_ERR "cpufreq: Unsupported CPU version\n");
 423                 goto bail_noprops;
 424         }
 425
 426         /* Look for the powertune data in the device-tree */
 427         g5_pmode_data = (u32 *)get_property(cpunode, "power-mode-data",&psize);
 428         if (!g5_pmode_data) {
 429                 DBG("No power-mode-data !\n");
 430                 goto bail_noprops;
 431         }
 432         g5_pmode_max = psize / sizeof(u32) - 1;
 433
 434         if (use_volts_smu) {
 435                 struct smu_sdbp_header *shdr;
 436
 437                 /* Look for the FVT table */
 438                 shdr = smu_get_sdb_partition(SMU_SDB_FVT_ID, NULL);
 439                 if (!shdr)
 440                         goto bail_noprops;
 441                 g5_fvt_table = (struct smu_sdbp_fvt *)&shdr[1];
 442                 ssize = (shdr->len * sizeof(u32)) -
 443                         sizeof(struct smu_sdbp_header);
 444                 g5_fvt_count = ssize / sizeof(struct smu_sdbp_fvt);
 445                 g5_fvt_cur = 0;
 446
 447                 /* Sanity checking */
 448                 if (g5_fvt_count < 1 || g5_pmode_max < 1)
 449                         goto bail_noprops;
 450
 451                 g5_switch_volt = g5_smu_switch_volt;
 452                 volt_method = "SMU";
 453         } else if (use_volts_vdnap) {
 454                 struct device_node *root;
 455
 456                 root = of_find_node_by_path("/");
 457                 if (root == NULL) {
 458                         printk(KERN_ERR "cpufreq: Can't find root of "
 459                                "device tree\n");
 460                         goto bail_noprops;
 461                 }
 462                 pfunc_set_vdnap0 = pmf_find_function(root, "set-vdnap0");
 463                 pfunc_vdnap0_complete =
 464                         pmf_find_function(root, "slewing-done");
 465                 if (pfunc_set_vdnap0 == NULL ||
 466                     pfunc_vdnap0_complete == NULL) {
 467                         printk(KERN_ERR "cpufreq: Can't find required "
 468                                "platform function\n");
 469                         goto bail_noprops;
 470                 }
 471
 472                 g5_switch_volt = g5_vdnap_switch_volt;
 473                 volt_method = "GPIO";
 474         } else {
 475                 g5_switch_volt = g5_dummy_switch_volt;
 476                 volt_method = "none";
 477         }
 478
 479         /*
 480          * From what I see, clock-frequency is always the maximal frequency.
 481          * The current driver can not slew sysclk yet, so we really only deal
 482          * with powertune steps for now. We also only implement full freq and
 483          * half freq in this version. So far, I haven't yet seen a machine
 484          * supporting anything else.
 485          */
 486         valp = (u32 *)get_property(cpunode, "clock-frequency", NULL);
 487         if (!valp)
 488                 return -ENODEV;
 489         max_freq = (*valp)/1000;
 490         g5_cpu_freqs[0].frequency = max_freq;
 491         g5_cpu_freqs[1].frequency = max_freq/2;
 492
 493         /* Set callbacks */
 494         g5_switch_freq = g5_scom_switch_freq;
 495         g5_query_freq = g5_scom_query_freq;
 496         freq_method = "SCOM";
 497
 498         /* Force apply current frequency to make sure everything is in
 499          * sync (voltage is right for example). Firmware may leave us with
 500          * a strange setting ...
 501          */
 502         g5_switch_volt(CPUFREQ_HIGH);
 503         msleep(10);
 504         g5_pmode_cur = -1;
 505         g5_switch_freq(g5_query_freq());
 506
 507         printk(KERN_INFO "Registering G5 CPU frequency driver\n");
 508         printk(KERN_INFO "Frequency method: %s, Voltage method: %s\n",
 509                freq_method, volt_method);
 510         printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Cur: %d MHz\n",
 511                 g5_cpu_freqs[1].frequency/1000,
 512                 g5_cpu_freqs[0].frequency/1000,
 513                 g5_cpu_freqs[g5_pmode_cur].frequency/1000);
 514
 515         rc = cpufreq_register_driver(&g5_cpufreq_driver);
 516
 517         /* We keep the CPU node on hold... hopefully, Apple G5 don't have
 518          * hotplug CPU with a dynamic device-tree ...
 519          */
 520         return rc;
 521
 522  bail_noprops:
 523         of_node_put(cpunode);
 524
 525         return rc;
 526 }
 527
 528 static int __init g5_pm72_cpufreq_init(struct device_node *cpus)
 529 {
 530         struct device_node *cpuid = NULL, *hwclock = NULL, *cpunode = NULL;
 531         u8 *eeprom = NULL;
 532         u32 *valp;
 533         u64 max_freq, min_freq, ih, il;
 534         int has_volt = 1, rc = 0;
 535
 536         /* Get first CPU node */
 537         for (cpunode = NULL;
 538              (cpunode = of_get_next_child(cpus, cpunode)) != NULL;) {
 539                 if (!strcmp(cpunode->type, "cpu"))
 540                         break;
 541         }
 542         if (cpunode == NULL) {
 543                 printk(KERN_ERR "cpufreq: Can't find any CPU node\n");
 544                 return -ENODEV;
 545         }
 546
 547         /* Lookup the cpuid eeprom node */
 548         cpuid = of_find_node_by_path("/u3@0,f8000000/i2c@f8001000/cpuid@a0");
 549         if (cpuid != NULL)
 550                 eeprom = (u8 *)get_property(cpuid, "cpuid", NULL);
 551         if (eeprom == NULL) {
 552                 printk(KERN_ERR "cpufreq: Can't find cpuid EEPROM !\n");
 553                 rc = -ENODEV;
 554                 goto bail;
 555         }
 556
 557         /* Lookup the i2c hwclock */
 558         for (hwclock = NULL;
 559              (hwclock = of_find_node_by_name(hwclock, "i2c-hwclock")) != NULL;){
 560                 char *loc = get_property(hwclock, "hwctrl-location", NULL);
 561                 if (loc == NULL)
 562                         continue;
 563                 if (strcmp(loc, "CPU CLOCK"))
 564                         continue;
 565                 if (!get_property(hwclock, "platform-get-frequency", NULL))
 566                         continue;
 567                 break;
 568         }
 569         if (hwclock == NULL) {
 570                 printk(KERN_ERR "cpufreq: Can't find i2c clock chip !\n");
 571                 rc = -ENODEV;
 572                 goto bail;
 573         }
 574
 575         DBG("cpufreq: i2c clock chip found: %s\n", hwclock->full_name);
 576
 577         /* Now get all the platform functions */
 578         pfunc_cpu_getfreq =
 579                 pmf_find_function(hwclock, "get-frequency");
 580         pfunc_cpu_setfreq_high =
 581                 pmf_find_function(hwclock, "set-frequency-high");
 582         pfunc_cpu_setfreq_low =
 583                 pmf_find_function(hwclock, "set-frequency-low");
 584         pfunc_slewing_done =
 585                 pmf_find_function(hwclock, "slewing-done");
 586         pfunc_cpu0_volt_high =
 587                 pmf_find_function(hwclock, "set-voltage-high-0");
 588         pfunc_cpu0_volt_low =
 589                 pmf_find_function(hwclock, "set-voltage-low-0");
 590         pfunc_cpu1_volt_high =
 591                 pmf_find_function(hwclock, "set-voltage-high-1");
 592         pfunc_cpu1_volt_low =
 593                 pmf_find_function(hwclock, "set-voltage-low-1");
 594
 595         /* Check we have minimum requirements */
 596         if (pfunc_cpu_getfreq == NULL || pfunc_cpu_setfreq_high == NULL ||
 597             pfunc_cpu_setfreq_low == NULL || pfunc_slewing_done == NULL) {
 598                 printk(KERN_ERR "cpufreq: Can't find platform functions !\n");
 599                 rc = -ENODEV;
 600                 goto bail;
 601         }
 602
 603         /* Check that we have complete sets */
 604         if (pfunc_cpu0_volt_high == NULL || pfunc_cpu0_volt_low == NULL) {
 605                 pmf_put_function(pfunc_cpu0_volt_high);
 606                 pmf_put_function(pfunc_cpu0_volt_low);
 607                 pfunc_cpu0_volt_high = pfunc_cpu0_volt_low = NULL;
 608                 has_volt = 0;
 609         }
 610         if (!has_volt ||
 611             pfunc_cpu1_volt_high == NULL || pfunc_cpu1_volt_low == NULL) {
 612                 pmf_put_function(pfunc_cpu1_volt_high);
 613                 pmf_put_function(pfunc_cpu1_volt_low);
 614                 pfunc_cpu1_volt_high = pfunc_cpu1_volt_low = NULL;
 615         }
 616
 617         /* Note: The device tree also contains a "platform-set-values"
 618          * function for which I haven't quite figured out the usage. It
 619          * might have to be called on init and/or wakeup, I'm not too sure
 620          * but things seem to work fine without it so far ...
 621          */
 622
 623         /* Get max frequency from device-tree */
 624         valp = (u32 *)get_property(cpunode, "clock-frequency", NULL);
 625         if (!valp) {
 626                 printk(KERN_ERR "cpufreq: Can't find CPU frequency !\n");
 627                 rc = -ENODEV;
 628                 goto bail;
 629         }
 630
 631         max_freq = (*valp)/1000;
 632
 633         /* Now calculate reduced frequency by using the cpuid input freq
 634          * ratio. This requires 64 bits math unless we are willing to lose
 635          * some precision
 636          */
 637         ih = *((u32 *)(eeprom + 0x10));
 638         il = *((u32 *)(eeprom + 0x20));
 639         min_freq = 0;
 640         if (ih != 0 && il != 0)
 641                 min_freq = (max_freq * il) / ih;
 642
 643         /* Sanity check */
 644         if (min_freq >= max_freq || min_freq < 1000) {
 645                 printk(KERN_ERR "cpufreq: Can't calculate low frequency !\n");
 646                 rc = -ENODEV;
 647                 goto bail;
 648         }
 649         g5_cpu_freqs[0].frequency = max_freq;
 650         g5_cpu_freqs[1].frequency = min_freq;
 651
 652         /* Set callbacks */
 653         g5_switch_volt = g5_pfunc_switch_volt;
 654         g5_switch_freq = g5_pfunc_switch_freq;
 655         g5_query_freq = g5_pfunc_query_freq;
 656
 657         /* Force apply current frequency to make sure everything is in
 658          * sync (voltage is right for example). Firmware may leave us with
 659          * a strange setting ...
 660          */
 661         g5_switch_volt(CPUFREQ_HIGH);
 662         msleep(10);
 663         g5_pmode_cur = -1;
 664         g5_switch_freq(g5_query_freq());
 665
 666         printk(KERN_INFO "Registering G5 CPU frequency driver\n");
 667         printk(KERN_INFO "Frequency method: i2c/pfunc, "
 668                "Voltage method: %s\n", has_volt ? "i2c/pfunc" : "none");
 669         printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Cur: %d MHz\n",
 670                 g5_cpu_freqs[1].frequency/1000,
 671                 g5_cpu_freqs[0].frequency/1000,
 672                 g5_cpu_freqs[g5_pmode_cur].frequency/1000);
 673
 674         rc = cpufreq_register_driver(&g5_cpufreq_driver);
 675  bail:
 676         if (rc != 0) {
 677                 pmf_put_function(pfunc_cpu_getfreq);
 678                 pmf_put_function(pfunc_cpu_setfreq_high);
 679                 pmf_put_function(pfunc_cpu_setfreq_low);
 680                 pmf_put_function(pfunc_slewing_done);
 681                 pmf_put_function(pfunc_cpu0_volt_high);
 682                 pmf_put_function(pfunc_cpu0_volt_low);
 683                 pmf_put_function(pfunc_cpu1_volt_high);
 684                 pmf_put_function(pfunc_cpu1_volt_low);
 685         }
 686         of_node_put(hwclock);
 687         of_node_put(cpuid);
 688         of_node_put(cpunode);
 689
 690         return rc;
 691 }
 692
 693 static int __init g5_rm31_cpufreq_init(struct device_node *cpus)
 694 {
 695         /* NYI */
 696         return 0;
 697 }
 698
 699 static int __init g5_cpufreq_init(void)
 700 {
 701         struct device_node *cpus;
 702         int rc;
 703
 704         cpus = of_find_node_by_path("/cpus");
 705         if (cpus == NULL) {
 706                 DBG("No /cpus node !\n");
 707                 return -ENODEV;
 708         }
 709
 710         if (machine_is_compatible("PowerMac7,2") ||
 711             machine_is_compatible("PowerMac7,3"))
 712                 rc = g5_pm72_cpufreq_init(cpus);
 713         else if (machine_is_compatible("RackMac3,1"))
 714                 rc = g5_rm31_cpufreq_init(cpus);
 715         else
 716                 rc = g5_neo2_cpufreq_init(cpus);
 717
 718         of_node_put(cpus);
 719         return rc;
 720 }
 721
 722 module_init(g5_cpufreq_init);
 723
 724
 725 MODULE_LICENSE("GPL");