drivers/cpufreq/pmac64-cpufreq.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 #undef DEBUG
  14
  15 #include <linux/module.h>
  16 #include <linux/types.h>
  17 #include <linux/errno.h>
  18 #include <linux/kernel.h>
  19 #include <linux/delay.h>
  20 #include <linux/sched.h>
  21 #include <linux/cpufreq.h>
  22 #include <linux/init.h>
  23 #include <linux/completion.h>
  24 #include <linux/mutex.h>
  25 #include <asm/prom.h>
  26 #include <asm/machdep.h>
  27 #include <asm/irq.h>
  28 #include <asm/sections.h>
  29 #include <asm/cputable.h>
  30 #include <asm/time.h>
  31 #include <asm/smu.h>
  32 #include <asm/pmac_pfunc.h>
  33
  34 #define DBG(fmt...) pr_debug(fmt)
  35
  36 /* see 970FX user manual */
  37
  38 #define SCOM_PCR 0x0aa001                       /* PCR scom addr */
  39
  40 #define PCR_HILO_SELECT         0x80000000U     /* 1 = PCR, 0 = PCRH */
  41 #define PCR_SPEED_FULL          0x00000000U     /* 1:1 speed value */
  42 #define PCR_SPEED_HALF          0x00020000U     /* 1:2 speed value */
  43 #define PCR_SPEED_QUARTER       0x00040000U     /* 1:4 speed value */
  44 #define PCR_SPEED_MASK          0x000e0000U     /* speed mask */
  45 #define PCR_SPEED_SHIFT         17
  46 #define PCR_FREQ_REQ_VALID      0x00010000U     /* freq request valid */
  47 #define PCR_VOLT_REQ_VALID      0x00008000U     /* volt request valid */
  48 #define PCR_TARGET_TIME_MASK    0x00006000U     /* target time */
  49 #define PCR_STATLAT_MASK        0x00001f00U     /* STATLAT value */
  50 #define PCR_SNOOPLAT_MASK       0x000000f0U     /* SNOOPLAT value */
  51 #define PCR_SNOOPACC_MASK       0x0000000fU     /* SNOOPACC value */
  52
  53 #define SCOM_PSR 0x408001                       /* PSR scom addr */
  54 /* warning: PSR is a 64 bits register */
  55 #define PSR_CMD_RECEIVED        0x2000000000000000U   /* command received */
  56 #define PSR_CMD_COMPLETED       0x1000000000000000U   /* command completed */
  57 #define PSR_CUR_SPEED_MASK      0x0300000000000000U   /* current speed */
  58 #define PSR_CUR_SPEED_SHIFT     (56)
  59
  60 /*
  61  * The G5 only supports two frequencies (Quarter speed is not supported)
  62  */
  63 #define CPUFREQ_HIGH                  0
  64 #define CPUFREQ_LOW                   1
  65
  66 static struct cpufreq_frequency_table g5_cpu_freqs[] = {
  67         {CPUFREQ_HIGH,          0},
  68         {CPUFREQ_LOW,           0},
  69         {0,                     CPUFREQ_TABLE_END},
  70 };
  71
  72 static struct freq_attr* g5_cpu_freqs_attr[] = {
  73         &cpufreq_freq_attr_scaling_available_freqs,
  74         NULL,
  75 };
  76
  77 /* Power mode data is an array of the 32 bits PCR values to use for
  78  * the various frequencies, retrieved from the device-tree
  79  */
  80 static int g5_pmode_cur;
  81
  82 static void (*g5_switch_volt)(int speed_mode);
  83 static int (*g5_switch_freq)(int speed_mode);
  84 static int (*g5_query_freq)(void);
  85
  86 static DEFINE_MUTEX(g5_switch_mutex);
  87
  88 static unsigned long transition_latency;
  89
  90 #ifdef CONFIG_PMAC_SMU
  91
  92 static const u32 *g5_pmode_data;
  93 static int g5_pmode_max;
  94
  95 static struct smu_sdbp_fvt *g5_fvt_table;       /* table of op. points */
  96 static int g5_fvt_count;                        /* number of op. points */
  97 static int g5_fvt_cur;                          /* current op. point */
  98
  99 /*
 100  * SMU based voltage switching for Neo2 platforms
 101  */
 102
 103 static void g5_smu_switch_volt(int speed_mode)
 104 {
 105         struct smu_simple_cmd   cmd;
 106
 107         DECLARE_COMPLETION_ONSTACK(comp);
 108         smu_queue_simple(&cmd, SMU_CMD_POWER_COMMAND, 8, smu_done_complete,
 109                          &comp, 'V', 'S', 'L', 'E', 'W',
 110                          0xff, g5_fvt_cur+1, speed_mode);
 111         wait_for_completion(&comp);
 112 }
 113
 114 /*
 115  * Platform function based voltage/vdnap switching for Neo2
 116  */
 117
 118 static struct pmf_function *pfunc_set_vdnap0;
 119 static struct pmf_function *pfunc_vdnap0_complete;
 120
 121 static void g5_vdnap_switch_volt(int speed_mode)
 122 {
 123         struct pmf_args args;
 124         u32 slew, done = 0;
 125         unsigned long timeout;
 126
 127         slew = (speed_mode == CPUFREQ_LOW) ? 1 : 0;
 128         args.count = 1;
 129         args.u[0].p = &slew;
 130
 131         pmf_call_one(pfunc_set_vdnap0, &args);
 132
 133         /* It's an irq GPIO so we should be able to just block here,
 134          * I'll do that later after I've properly tested the IRQ code for
 135          * platform functions
 136          */
 137         timeout = jiffies + HZ/10;
 138         while(!time_after(jiffies, timeout)) {
 139                 args.count = 1;
 140                 args.u[0].p = &done;
 141                 pmf_call_one(pfunc_vdnap0_complete, &args);
 142                 if (done)
 143                         break;
 144                 msleep(1);
 145         }
 146         if (done == 0)
 147                 printk(KERN_WARNING "cpufreq: Timeout in clock slewing !\n");
 148 }
 149
 150
 151 /*
 152  * SCOM based frequency switching for 970FX rev3
 153  */
 154 static int g5_scom_switch_freq(int speed_mode)
 155 {
 156         unsigned long flags;
 157         int to;
 158
 159         /* If frequency is going up, first ramp up the voltage */
 160         if (speed_mode < g5_pmode_cur)
 161                 g5_switch_volt(speed_mode);
 162
 163         local_irq_save(flags);
 164
 165         /* Clear PCR high */
 166         scom970_write(SCOM_PCR, 0);
 167         /* Clear PCR low */
 168         scom970_write(SCOM_PCR, PCR_HILO_SELECT | 0);
 169         /* Set PCR low */
 170         scom970_write(SCOM_PCR, PCR_HILO_SELECT |
 171                       g5_pmode_data[speed_mode]);
 172
 173         /* Wait for completion */
 174         for (to = 0; to < 10; to++) {
 175                 unsigned long psr = scom970_read(SCOM_PSR);
 176
 177                 if ((psr & PSR_CMD_RECEIVED) == 0 &&
 178                     (((psr >> PSR_CUR_SPEED_SHIFT) ^
 179                       (g5_pmode_data[speed_mode] >> PCR_SPEED_SHIFT)) & 0x3)
 180                     == 0)
 181                         break;
 182                 if (psr & PSR_CMD_COMPLETED)
 183                         break;
 184                 udelay(100);
 185         }
 186
 187         local_irq_restore(flags);
 188
 189         /* If frequency is going down, last ramp the voltage */
 190         if (speed_mode > g5_pmode_cur)
 191                 g5_switch_volt(speed_mode);
 192
 193         g5_pmode_cur = speed_mode;
 194         ppc_proc_freq = g5_cpu_freqs[speed_mode].frequency * 1000ul;
 195
 196         return 0;
 197 }
 198
 199 static int g5_scom_query_freq(void)
 200 {
 201         unsigned long psr = scom970_read(SCOM_PSR);
 202         int i;
 203
 204         for (i = 0; i <= g5_pmode_max; i++)
 205                 if ((((psr >> PSR_CUR_SPEED_SHIFT) ^
 206                       (g5_pmode_data[i] >> PCR_SPEED_SHIFT)) & 0x3) == 0)
 207                         break;
 208         return i;
 209 }
 210
 211 /*
 212  * Fake voltage switching for platforms with missing support
 213  */
 214
 215 static void g5_dummy_switch_volt(int speed_mode)
 216 {
 217 }
 218
 219 #endif /* CONFIG_PMAC_SMU */
 220
 221 /*
 222  * Platform function based voltage switching for PowerMac7,2 & 7,3
 223  */
 224
 225 static struct pmf_function *pfunc_cpu0_volt_high;
 226 static struct pmf_function *pfunc_cpu0_volt_low;
 227 static struct pmf_function *pfunc_cpu1_volt_high;
 228 static struct pmf_function *pfunc_cpu1_volt_low;
 229
 230 static void g5_pfunc_switch_volt(int speed_mode)
 231 {
 232         if (speed_mode == CPUFREQ_HIGH) {
 233                 if (pfunc_cpu0_volt_high)
 234                         pmf_call_one(pfunc_cpu0_volt_high, NULL);
 235                 if (pfunc_cpu1_volt_high)
 236                         pmf_call_one(pfunc_cpu1_volt_high, NULL);
 237         } else {
 238                 if (pfunc_cpu0_volt_low)
 239                         pmf_call_one(pfunc_cpu0_volt_low, NULL);
 240                 if (pfunc_cpu1_volt_low)
 241                         pmf_call_one(pfunc_cpu1_volt_low, NULL);
 242         }
 243         msleep(10); /* should be faster , to fix */
 244 }
 245
 246 /*
 247  * Platform function based frequency switching for PowerMac7,2 & 7,3
 248  */
 249
 250 static struct pmf_function *pfunc_cpu_setfreq_high;
 251 static struct pmf_function *pfunc_cpu_setfreq_low;
 252 static struct pmf_function *pfunc_cpu_getfreq;
 253 static struct pmf_function *pfunc_slewing_done;
 254
 255 static int g5_pfunc_switch_freq(int speed_mode)
 256 {
 257         struct pmf_args args;
 258         u32 done = 0;
 259         unsigned long timeout;
 260         int rc;
 261
 262         DBG("g5_pfunc_switch_freq(%d)\n", speed_mode);
 263
 264         /* If frequency is going up, first ramp up the voltage */
 265         if (speed_mode < g5_pmode_cur)
 266                 g5_switch_volt(speed_mode);
 267
 268         /* Do it */
 269         if (speed_mode == CPUFREQ_HIGH)
 270                 rc = pmf_call_one(pfunc_cpu_setfreq_high, NULL);
 271         else
 272                 rc = pmf_call_one(pfunc_cpu_setfreq_low, NULL);
 273
 274         if (rc)
 275                 printk(KERN_WARNING "cpufreq: pfunc switch error %d\n", rc);
 276
 277         /* It's an irq GPIO so we should be able to just block here,
 278          * I'll do that later after I've properly tested the IRQ code for
 279          * platform functions
 280          */
 281         timeout = jiffies + HZ/10;
 282         while(!time_after(jiffies, timeout)) {
 283                 args.count = 1;
 284                 args.u[0].p = &done;
 285                 pmf_call_one(pfunc_slewing_done, &args);
 286                 if (done)
 287                         break;
 288                 msleep(1);
 289         }
 290         if (done == 0)
 291                 printk(KERN_WARNING "cpufreq: Timeout in clock slewing !\n");
 292
 293         /* If frequency is going down, last ramp the voltage */
 294         if (speed_mode > g5_pmode_cur)
 295                 g5_switch_volt(speed_mode);
 296
 297         g5_pmode_cur = speed_mode;
 298         ppc_proc_freq = g5_cpu_freqs[speed_mode].frequency * 1000ul;
 299
 300         return 0;
 301 }
 302
 303 static int g5_pfunc_query_freq(void)
 304 {
 305         struct pmf_args args;
 306         u32 val = 0;
 307
 308         args.count = 1;
 309         args.u[0].p = &val;
 310         pmf_call_one(pfunc_cpu_getfreq, &args);
 311         return val ? CPUFREQ_HIGH : CPUFREQ_LOW;
 312 }
 313
 314
 315 /*
 316  * Common interface to the cpufreq core
 317  */
 318
 319 static int g5_cpufreq_verify(struct cpufreq_policy *policy)
 320 {
 321         return cpufreq_frequency_table_verify(policy, g5_cpu_freqs);
 322 }
 323
 324 static int g5_cpufreq_target(struct cpufreq_policy *policy,
 325         unsigned int target_freq, unsigned int relation)
 326 {
 327         unsigned int newstate = 0;
 328         struct cpufreq_freqs freqs;
 329         int rc;
 330
 331         if (cpufreq_frequency_table_target(policy, g5_cpu_freqs,
 332                         target_freq, relation, &newstate))
 333                 return -EINVAL;
 334
 335         if (g5_pmode_cur == newstate)
 336                 return 0;
 337
 338         mutex_lock(&g5_switch_mutex);
 339
 340         freqs.old = g5_cpu_freqs[g5_pmode_cur].frequency;
 341         freqs.new = g5_cpu_freqs[newstate].frequency;
 342
 343         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
 344         rc = g5_switch_freq(newstate);
 345         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 346
 347         mutex_unlock(&g5_switch_mutex);
 348
 349         return rc;
 350 }
 351
 352 static unsigned int g5_cpufreq_get_speed(unsigned int cpu)
 353 {
 354         return g5_cpu_freqs[g5_pmode_cur].frequency;
 355 }
 356
 357 static int g5_cpufreq_cpu_init(struct cpufreq_policy *policy)
 358 {
 359         policy->cpuinfo.transition_latency = transition_latency;
 360         policy->cur = g5_cpu_freqs[g5_query_freq()].frequency;
 361         /* secondary CPUs are tied to the primary one by the
 362          * cpufreq core if in the secondary policy we tell it that
 363          * it actually must be one policy together with all others. */
 364         cpumask_copy(policy->cpus, cpu_online_mask);
 365         cpufreq_frequency_table_get_attr(g5_cpu_freqs, policy->cpu);
 366
 367         return cpufreq_frequency_table_cpuinfo(policy,
 368                 g5_cpu_freqs);
 369 }
 370
 371
 372 static struct cpufreq_driver g5_cpufreq_driver = {
 373         .name           = "powermac",
 374         .owner          = THIS_MODULE,
 375         .flags          = CPUFREQ_CONST_LOOPS,
 376         .init           = g5_cpufreq_cpu_init,
 377         .verify         = g5_cpufreq_verify,
 378         .target         = g5_cpufreq_target,
 379         .get            = g5_cpufreq_get_speed,
 380         .attr           = g5_cpu_freqs_attr,
 381 };
 382
 383
 384 #ifdef CONFIG_PMAC_SMU
 385
 386 static int __init g5_neo2_cpufreq_init(struct device_node *cpus)
 387 {
 388         struct device_node *cpunode;
 389         unsigned int psize, ssize;
 390         unsigned long max_freq;
 391         char *freq_method, *volt_method;
 392         const u32 *valp;
 393         u32 pvr_hi;
 394         int use_volts_vdnap = 0;
 395         int use_volts_smu = 0;
 396         int rc = -ENODEV;
 397
 398         /* Check supported platforms */
 399         if (of_machine_is_compatible("PowerMac8,1") ||
 400             of_machine_is_compatible("PowerMac8,2") ||
 401             of_machine_is_compatible("PowerMac9,1"))
 402                 use_volts_smu = 1;
 403         else if (of_machine_is_compatible("PowerMac11,2"))
 404                 use_volts_vdnap = 1;
 405         else
 406                 return -ENODEV;
 407
 408         /* Get first CPU node */
 409         for (cpunode = NULL;
 410              (cpunode = of_get_next_child(cpus, cpunode)) != NULL;) {
 411                 const u32 *reg = of_get_property(cpunode, "reg", NULL);
 412                 if (reg == NULL || (*reg) != 0)
 413                         continue;
 414                 if (!strcmp(cpunode->type, "cpu"))
 415                         break;
 416         }
 417         if (cpunode == NULL) {
 418                 printk(KERN_ERR "cpufreq: Can't find any CPU 0 node\n");
 419                 return -ENODEV;
 420         }
 421
 422         /* Check 970FX for now */
 423         valp = of_get_property(cpunode, "cpu-version", NULL);
 424         if (!valp) {
 425                 DBG("No cpu-version property !\n");
 426                 goto bail_noprops;
 427         }
 428         pvr_hi = (*valp) >> 16;
 429         if (pvr_hi != 0x3c && pvr_hi != 0x44) {
 430                 printk(KERN_ERR "cpufreq: Unsupported CPU version\n");
 431                 goto bail_noprops;
 432         }
 433
 434         /* Look for the powertune data in the device-tree */
 435         g5_pmode_data = of_get_property(cpunode, "power-mode-data",&psize);
 436         if (!g5_pmode_data) {
 437                 DBG("No power-mode-data !\n");
 438                 goto bail_noprops;
 439         }
 440         g5_pmode_max = psize / sizeof(u32) - 1;
 441
 442         if (use_volts_smu) {
 443                 const struct smu_sdbp_header *shdr;
 444
 445                 /* Look for the FVT table */
 446                 shdr = smu_get_sdb_partition(SMU_SDB_FVT_ID, NULL);
 447                 if (!shdr)
 448                         goto bail_noprops;
 449                 g5_fvt_table = (struct smu_sdbp_fvt *)&shdr[1];
 450                 ssize = (shdr->len * sizeof(u32)) -
 451                         sizeof(struct smu_sdbp_header);
 452                 g5_fvt_count = ssize / sizeof(struct smu_sdbp_fvt);
 453                 g5_fvt_cur = 0;
 454
 455                 /* Sanity checking */
 456                 if (g5_fvt_count < 1 || g5_pmode_max < 1)
 457                         goto bail_noprops;
 458
 459                 g5_switch_volt = g5_smu_switch_volt;
 460                 volt_method = "SMU";
 461         } else if (use_volts_vdnap) {
 462                 struct device_node *root;
 463
 464                 root = of_find_node_by_path("/");
 465                 if (root == NULL) {
 466                         printk(KERN_ERR "cpufreq: Can't find root of "
 467                                "device tree\n");
 468                         goto bail_noprops;
 469                 }
 470                 pfunc_set_vdnap0 = pmf_find_function(root, "set-vdnap0");
 471                 pfunc_vdnap0_complete =
 472                         pmf_find_function(root, "slewing-done");
 473                 if (pfunc_set_vdnap0 == NULL ||
 474                     pfunc_vdnap0_complete == NULL) {
 475                         printk(KERN_ERR "cpufreq: Can't find required "
 476                                "platform function\n");
 477                         goto bail_noprops;
 478                 }
 479
 480                 g5_switch_volt = g5_vdnap_switch_volt;
 481                 volt_method = "GPIO";
 482         } else {
 483                 g5_switch_volt = g5_dummy_switch_volt;
 484                 volt_method = "none";
 485         }
 486
 487         /*
 488          * From what I see, clock-frequency is always the maximal frequency.
 489          * The current driver can not slew sysclk yet, so we really only deal
 490          * with powertune steps for now. We also only implement full freq and
 491          * half freq in this version. So far, I haven't yet seen a machine
 492          * supporting anything else.
 493          */
 494         valp = of_get_property(cpunode, "clock-frequency", NULL);
 495         if (!valp)
 496                 return -ENODEV;
 497         max_freq = (*valp)/1000;
 498         g5_cpu_freqs[0].frequency = max_freq;
 499         g5_cpu_freqs[1].frequency = max_freq/2;
 500
 501         /* Set callbacks */
 502         transition_latency = 12000;
 503         g5_switch_freq = g5_scom_switch_freq;
 504         g5_query_freq = g5_scom_query_freq;
 505         freq_method = "SCOM";
 506
 507         /* Force apply current frequency to make sure everything is in
 508          * sync (voltage is right for example). Firmware may leave us with
 509          * a strange setting ...
 510          */
 511         g5_switch_volt(CPUFREQ_HIGH);
 512         msleep(10);
 513         g5_pmode_cur = -1;
 514         g5_switch_freq(g5_query_freq());
 515
 516         printk(KERN_INFO "Registering G5 CPU frequency driver\n");
 517         printk(KERN_INFO "Frequency method: %s, Voltage method: %s\n",
 518                freq_method, volt_method);
 519         printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Cur: %d MHz\n",
 520                 g5_cpu_freqs[1].frequency/1000,
 521                 g5_cpu_freqs[0].frequency/1000,
 522                 g5_cpu_freqs[g5_pmode_cur].frequency/1000);
 523
 524         rc = cpufreq_register_driver(&g5_cpufreq_driver);
 525
 526         /* We keep the CPU node on hold... hopefully, Apple G5 don't have
 527          * hotplug CPU with a dynamic device-tree ...
 528          */
 529         return rc;
 530
 531  bail_noprops:
 532         of_node_put(cpunode);
 533
 534         return rc;
 535 }
 536
 537 #endif /* CONFIG_PMAC_SMU */
 538
 539
 540 static int __init g5_pm72_cpufreq_init(struct device_node *cpus)
 541 {
 542         struct device_node *cpuid = NULL, *hwclock = NULL, *cpunode = NULL;
 543         const u8 *eeprom = NULL;
 544         const u32 *valp;
 545         u64 max_freq, min_freq, ih, il;
 546         int has_volt = 1, rc = 0;
 547
 548         DBG("cpufreq: Initializing for PowerMac7,2, PowerMac7,3 and"
 549             " RackMac3,1...\n");
 550
 551         /* Get first CPU node */
 552         for (cpunode = NULL;
 553              (cpunode = of_get_next_child(cpus, cpunode)) != NULL;) {
 554                 if (!strcmp(cpunode->type, "cpu"))
 555                         break;
 556         }
 557         if (cpunode == NULL) {
 558                 printk(KERN_ERR "cpufreq: Can't find any CPU node\n");
 559                 return -ENODEV;
 560         }
 561
 562         /* Lookup the cpuid eeprom node */
 563         cpuid = of_find_node_by_path("/u3@0,f8000000/i2c@f8001000/cpuid@a0");
 564         if (cpuid != NULL)
 565                 eeprom = of_get_property(cpuid, "cpuid", NULL);
 566         if (eeprom == NULL) {
 567                 printk(KERN_ERR "cpufreq: Can't find cpuid EEPROM !\n");
 568                 rc = -ENODEV;
 569                 goto bail;
 570         }
 571
 572         /* Lookup the i2c hwclock */
 573         for (hwclock = NULL;
 574              (hwclock = of_find_node_by_name(hwclock, "i2c-hwclock")) != NULL;){
 575                 const char *loc = of_get_property(hwclock,
 576                                 "hwctrl-location", NULL);
 577                 if (loc == NULL)
 578                         continue;
 579                 if (strcmp(loc, "CPU CLOCK"))
 580                         continue;
 581                 if (!of_get_property(hwclock, "platform-get-frequency", NULL))
 582                         continue;
 583                 break;
 584         }
 585         if (hwclock == NULL) {
 586                 printk(KERN_ERR "cpufreq: Can't find i2c clock chip !\n");
 587                 rc = -ENODEV;
 588                 goto bail;
 589         }
 590
 591         DBG("cpufreq: i2c clock chip found: %s\n", hwclock->full_name);
 592
 593         /* Now get all the platform functions */
 594         pfunc_cpu_getfreq =
 595                 pmf_find_function(hwclock, "get-frequency");
 596         pfunc_cpu_setfreq_high =
 597                 pmf_find_function(hwclock, "set-frequency-high");
 598         pfunc_cpu_setfreq_low =
 599                 pmf_find_function(hwclock, "set-frequency-low");
 600         pfunc_slewing_done =
 601                 pmf_find_function(hwclock, "slewing-done");
 602         pfunc_cpu0_volt_high =
 603                 pmf_find_function(hwclock, "set-voltage-high-0");
 604         pfunc_cpu0_volt_low =
 605                 pmf_find_function(hwclock, "set-voltage-low-0");
 606         pfunc_cpu1_volt_high =
 607                 pmf_find_function(hwclock, "set-voltage-high-1");
 608         pfunc_cpu1_volt_low =
 609                 pmf_find_function(hwclock, "set-voltage-low-1");
 610
 611         /* Check we have minimum requirements */
 612         if (pfunc_cpu_getfreq == NULL || pfunc_cpu_setfreq_high == NULL ||
 613             pfunc_cpu_setfreq_low == NULL || pfunc_slewing_done == NULL) {
 614                 printk(KERN_ERR "cpufreq: Can't find platform functions !\n");
 615                 rc = -ENODEV;
 616                 goto bail;
 617         }
 618
 619         /* Check that we have complete sets */
 620         if (pfunc_cpu0_volt_high == NULL || pfunc_cpu0_volt_low == NULL) {
 621                 pmf_put_function(pfunc_cpu0_volt_high);
 622                 pmf_put_function(pfunc_cpu0_volt_low);
 623                 pfunc_cpu0_volt_high = pfunc_cpu0_volt_low = NULL;
 624                 has_volt = 0;
 625         }
 626         if (!has_volt ||
 627             pfunc_cpu1_volt_high == NULL || pfunc_cpu1_volt_low == NULL) {
 628                 pmf_put_function(pfunc_cpu1_volt_high);
 629                 pmf_put_function(pfunc_cpu1_volt_low);
 630                 pfunc_cpu1_volt_high = pfunc_cpu1_volt_low = NULL;
 631         }
 632
 633         /* Note: The device tree also contains a "platform-set-values"
 634          * function for which I haven't quite figured out the usage. It
 635          * might have to be called on init and/or wakeup, I'm not too sure
 636          * but things seem to work fine without it so far ...
 637          */
 638
 639         /* Get max frequency from device-tree */
 640         valp = of_get_property(cpunode, "clock-frequency", NULL);
 641         if (!valp) {
 642                 printk(KERN_ERR "cpufreq: Can't find CPU frequency !\n");
 643                 rc = -ENODEV;
 644                 goto bail;
 645         }
 646
 647         max_freq = (*valp)/1000;
 648
 649         /* Now calculate reduced frequency by using the cpuid input freq
 650          * ratio. This requires 64 bits math unless we are willing to lose
 651          * some precision
 652          */
 653         ih = *((u32 *)(eeprom + 0x10));
 654         il = *((u32 *)(eeprom + 0x20));
 655
 656         /* Check for machines with no useful settings */
 657         if (il == ih) {
 658                 printk(KERN_WARNING "cpufreq: No low frequency mode available"
 659                        " on this model !\n");
 660                 rc = -ENODEV;
 661                 goto bail;
 662         }
 663
 664         min_freq = 0;
 665         if (ih != 0 && il != 0)
 666                 min_freq = (max_freq * il) / ih;
 667
 668         /* Sanity check */
 669         if (min_freq >= max_freq || min_freq < 1000) {
 670                 printk(KERN_ERR "cpufreq: Can't calculate low frequency !\n");
 671                 rc = -ENXIO;
 672                 goto bail;
 673         }
 674         g5_cpu_freqs[0].frequency = max_freq;
 675         g5_cpu_freqs[1].frequency = min_freq;
 676
 677         /* Set callbacks */
 678         transition_latency = CPUFREQ_ETERNAL;
 679         g5_switch_volt = g5_pfunc_switch_volt;
 680         g5_switch_freq = g5_pfunc_switch_freq;
 681         g5_query_freq = g5_pfunc_query_freq;
 682
 683         /* Force apply current frequency to make sure everything is in
 684          * sync (voltage is right for example). Firmware may leave us with
 685          * a strange setting ...
 686          */
 687         g5_switch_volt(CPUFREQ_HIGH);
 688         msleep(10);
 689         g5_pmode_cur = -1;
 690         g5_switch_freq(g5_query_freq());
 691
 692         printk(KERN_INFO "Registering G5 CPU frequency driver\n");
 693         printk(KERN_INFO "Frequency method: i2c/pfunc, "
 694                "Voltage method: %s\n", has_volt ? "i2c/pfunc" : "none");
 695         printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Cur: %d MHz\n",
 696                 g5_cpu_freqs[1].frequency/1000,
 697                 g5_cpu_freqs[0].frequency/1000,
 698                 g5_cpu_freqs[g5_pmode_cur].frequency/1000);
 699
 700         rc = cpufreq_register_driver(&g5_cpufreq_driver);
 701  bail:
 702         if (rc != 0) {
 703                 pmf_put_function(pfunc_cpu_getfreq);
 704                 pmf_put_function(pfunc_cpu_setfreq_high);
 705                 pmf_put_function(pfunc_cpu_setfreq_low);
 706                 pmf_put_function(pfunc_slewing_done);
 707                 pmf_put_function(pfunc_cpu0_volt_high);
 708                 pmf_put_function(pfunc_cpu0_volt_low);
 709                 pmf_put_function(pfunc_cpu1_volt_high);
 710                 pmf_put_function(pfunc_cpu1_volt_low);
 711         }
 712         of_node_put(hwclock);
 713         of_node_put(cpuid);
 714         of_node_put(cpunode);
 715
 716         return rc;
 717 }
 718
 719 static int __init g5_cpufreq_init(void)
 720 {
 721         struct device_node *cpus;
 722         int rc = 0;
 723
 724         cpus = of_find_node_by_path("/cpus");
 725         if (cpus == NULL) {
 726                 DBG("No /cpus node !\n");
 727                 return -ENODEV;
 728         }
 729
 730         if (of_machine_is_compatible("PowerMac7,2") ||
 731             of_machine_is_compatible("PowerMac7,3") ||
 732             of_machine_is_compatible("RackMac3,1"))
 733                 rc = g5_pm72_cpufreq_init(cpus);
 734 #ifdef CONFIG_PMAC_SMU
 735         else
 736                 rc = g5_neo2_cpufreq_init(cpus);
 737 #endif /* CONFIG_PMAC_SMU */
 738
 739         of_node_put(cpus);
 740         return rc;
 741 }
 742
 743 module_init(g5_cpufreq_init);
 744
 745
 746 MODULE_LICENSE("GPL");