arch/ppc/platforms/pmac_cpufreq.c

   1 /*
   2  *  arch/ppc/platforms/pmac_cpufreq.c
   3  *
   4  *  Copyright (C) 2002 - 2004 Benjamin Herrenschmidt <benh@kernel.crashing.org>
   5  *  Copyright (C) 2004        John Steele Scott <toojays@toojays.net>
   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 version 2 as
   9  * published by the Free Software Foundation.
  10  *
  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/adb.h>
  21 #include <linux/pmu.h>
  22 #include <linux/slab.h>
  23 #include <linux/cpufreq.h>
  24 #include <linux/init.h>
  25 #include <linux/sysdev.h>
  26 #include <linux/i2c.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/open_pic.h>
  38
  39 /* WARNING !!! This will cause calibrate_delay() to be called,
  40  * but this is an __init function ! So you MUST go edit
  41  * init/main.c to make it non-init before enabling DEBUG_FREQ
  42  */
  43 #undef DEBUG_FREQ
  44
  45 /*
  46  * There is a problem with the core cpufreq code on SMP kernels,
  47  * it won't recalculate the Bogomips properly
  48  */
  49 #ifdef CONFIG_SMP
  50 #warning "WARNING, CPUFREQ not recommended on SMP kernels"
  51 #endif
  52
  53 extern void low_choose_7447a_dfs(int dfs);
  54 extern void low_choose_750fx_pll(int pll);
  55 extern void low_sleep_handler(void);
  56
  57 /*
  58  * Currently, PowerMac cpufreq supports only high & low frequencies
  59  * that are set by the firmware
  60  */
  61 static unsigned int low_freq;
  62 static unsigned int hi_freq;
  63 static unsigned int cur_freq;
  64
  65 /*
  66  * Different models uses different mecanisms to switch the frequency
  67  */
  68 static int (*set_speed_proc)(int low_speed);
  69
  70 /*
  71  * Some definitions used by the various speedprocs
  72  */
  73 static u32 voltage_gpio;
  74 static u32 frequency_gpio;
  75 static u32 slew_done_gpio;
  76
  77
  78 #define PMAC_CPU_LOW_SPEED      1
  79 #define PMAC_CPU_HIGH_SPEED     0
  80
  81 /* There are only two frequency states for each processor. Values
  82  * are in kHz for the time being.
  83  */
  84 #define CPUFREQ_HIGH                  PMAC_CPU_HIGH_SPEED
  85 #define CPUFREQ_LOW                   PMAC_CPU_LOW_SPEED
  86
  87 static struct cpufreq_frequency_table pmac_cpu_freqs[] = {
  88         {CPUFREQ_HIGH,          0},
  89         {CPUFREQ_LOW,           0},
  90         {0,                     CPUFREQ_TABLE_END},
  91 };
  92
  93 static inline void wakeup_decrementer(void)
  94 {
  95         set_dec(tb_ticks_per_jiffy);
  96         /* No currently-supported powerbook has a 601,
  97          * so use get_tbl, not native
  98          */
  99         last_jiffy_stamp(0) = tb_last_stamp = get_tbl();
 100 }
 101
 102 #ifdef DEBUG_FREQ
 103 static inline void debug_calc_bogomips(void)
 104 {
 105         /* This will cause a recalc of bogomips and display the
 106          * result. We backup/restore the value to avoid affecting the
 107          * core cpufreq framework's own calculation.
 108          */
 109         extern void calibrate_delay(void);
 110
 111         unsigned long save_lpj = loops_per_jiffy;
 112         calibrate_delay();
 113         loops_per_jiffy = save_lpj;
 114 }
 115 #endif /* DEBUG_FREQ */
 116
 117 /* Switch CPU speed under 750FX CPU control
 118  */
 119 static int __pmac cpu_750fx_cpu_speed(int low_speed)
 120 {
 121 #ifdef DEBUG_FREQ
 122         printk(KERN_DEBUG "HID1, before: %x\n", mfspr(SPRN_HID1));
 123 #endif
 124 #ifdef CONFIG_6xx
 125         low_choose_750fx_pll(low_speed);
 126 #endif
 127 #ifdef DEBUG_FREQ
 128         printk(KERN_DEBUG "HID1, after: %x\n", mfspr(SPRN_HID1));
 129         debug_calc_bogomips();
 130 #endif
 131
 132         return 0;
 133 }
 134
 135 /* Switch CPU speed using DFS */
 136 static int __pmac dfs_set_cpu_speed(int low_speed)
 137 {
 138         if (low_speed == 0) {
 139                 /* ramping up, set voltage first */
 140                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
 141                 /* Make sure we sleep for at least 1ms */
 142                 msleep(1);
 143         }
 144
 145         /* set frequency */
 146         low_choose_7447a_dfs(low_speed);
 147
 148         if (low_speed == 1) {
 149                 /* ramping down, set voltage last */
 150                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
 151                 msleep(1);
 152         }
 153
 154         return 0;
 155 }
 156
 157 static unsigned int __pmac dfs_get_cpu_speed(unsigned int cpu)
 158 {
 159         if (mfspr(HID1) & HID1_DFS)
 160                 return low_freq;
 161         else
 162                 return hi_freq;
 163 }
 164
 165
 166 /* Switch CPU speed using slewing GPIOs
 167  */
 168 static int __pmac gpios_set_cpu_speed(int low_speed)
 169 {
 170         int gpio;
 171
 172         /* If ramping up, set voltage first */
 173         if (low_speed == 0) {
 174                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
 175                 /* Delay is way too big but it's ok, we schedule */
 176                 msleep(10);
 177         }
 178
 179         /* Set frequency */
 180         pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, frequency_gpio,
 181                           low_speed ? 0x04 : 0x05);
 182         udelay(200);
 183         do {
 184                 set_current_state(TASK_UNINTERRUPTIBLE);
 185                 schedule_timeout(1);
 186                 gpio = pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, slew_done_gpio, 0);
 187         } while((gpio & 0x02) == 0);
 188
 189         /* If ramping down, set voltage last */
 190         if (low_speed == 1) {
 191                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
 192                 /* Delay is way too big but it's ok, we schedule */
 193                 msleep(10);
 194         }
 195
 196 #ifdef DEBUG_FREQ
 197         debug_calc_bogomips();
 198 #endif
 199
 200         return 0;
 201 }
 202
 203 /* Switch CPU speed under PMU control
 204  */
 205 static int __pmac pmu_set_cpu_speed(int low_speed)
 206 {
 207         struct adb_request req;
 208         unsigned long save_l2cr;
 209         unsigned long save_l3cr;
 210
 211         preempt_disable();
 212
 213 #ifdef DEBUG_FREQ
 214         printk(KERN_DEBUG "HID1, before: %x\n", mfspr(SPRN_HID1));
 215 #endif
 216         /* Disable all interrupt sources on openpic */
 217         openpic_set_priority(0xf);
 218
 219         /* Make sure the decrementer won't interrupt us */
 220         asm volatile("mtdec %0" : : "r" (0x7fffffff));
 221         /* Make sure any pending DEC interrupt occuring while we did
 222          * the above didn't re-enable the DEC */
 223         mb();
 224         asm volatile("mtdec %0" : : "r" (0x7fffffff));
 225
 226         /* We can now disable MSR_EE */
 227         local_irq_disable();
 228
 229         /* Giveup the FPU & vec */
 230         enable_kernel_fp();
 231
 232 #ifdef CONFIG_ALTIVEC
 233         if (cur_cpu_spec[0]->cpu_features & CPU_FTR_ALTIVEC)
 234                 enable_kernel_altivec();
 235 #endif /* CONFIG_ALTIVEC */
 236
 237         /* Save & disable L2 and L3 caches */
 238         save_l3cr = _get_L3CR();        /* (returns -1 if not available) */
 239         save_l2cr = _get_L2CR();        /* (returns -1 if not available) */
 240
 241         /* Send the new speed command. My assumption is that this command
 242          * will cause PLL_CFG[0..3] to be changed next time CPU goes to sleep
 243          */
 244         pmu_request(&req, NULL, 6, PMU_CPU_SPEED, 'W', 'O', 'O', 'F', low_speed);
 245         while (!req.complete)
 246                 pmu_poll();
 247
 248         /* Prepare the northbridge for the speed transition */
 249         pmac_call_feature(PMAC_FTR_SLEEP_STATE,NULL,1,1);
 250
 251         /* Call low level code to backup CPU state and recover from
 252          * hardware reset
 253          */
 254         low_sleep_handler();
 255
 256         /* Restore the northbridge */
 257         pmac_call_feature(PMAC_FTR_SLEEP_STATE,NULL,1,0);
 258
 259         /* Restore L2 cache */
 260         if (save_l2cr != 0xffffffff && (save_l2cr & L2CR_L2E) != 0)
 261                 _set_L2CR(save_l2cr);
 262         /* Restore L3 cache */
 263         if (save_l3cr != 0xffffffff && (save_l3cr & L3CR_L3E) != 0)
 264                 _set_L3CR(save_l3cr);
 265
 266         /* Restore userland MMU context */
 267         set_context(current->active_mm->context, current->active_mm->pgd);
 268
 269 #ifdef DEBUG_FREQ
 270         printk(KERN_DEBUG "HID1, after: %x\n", mfspr(SPRN_HID1));
 271 #endif
 272
 273         /* Restore low level PMU operations */
 274         pmu_unlock();
 275
 276         /* Restore decrementer */
 277         wakeup_decrementer();
 278
 279         /* Restore interrupts */
 280         openpic_set_priority(0);
 281
 282         /* Let interrupts flow again ... */
 283         local_irq_enable();
 284
 285 #ifdef DEBUG_FREQ
 286         debug_calc_bogomips();
 287 #endif
 288
 289         preempt_enable();
 290
 291         return 0;
 292 }
 293
 294 static int __pmac do_set_cpu_speed(int speed_mode)
 295 {
 296         struct cpufreq_freqs freqs;
 297
 298         freqs.old = cur_freq;
 299         freqs.new = (speed_mode == PMAC_CPU_HIGH_SPEED) ? hi_freq : low_freq;
 300         freqs.cpu = smp_processor_id();
 301
 302         if (freqs.old == freqs.new)
 303                 return 0;
 304
 305         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 306         set_speed_proc(speed_mode == PMAC_CPU_LOW_SPEED);
 307         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 308         cur_freq = (speed_mode == PMAC_CPU_HIGH_SPEED) ? hi_freq : low_freq;
 309
 310         return 0;
 311 }
 312
 313 static int __pmac pmac_cpufreq_verify(struct cpufreq_policy *policy)
 314 {
 315         return cpufreq_frequency_table_verify(policy, pmac_cpu_freqs);
 316 }
 317
 318 static int __pmac pmac_cpufreq_target(  struct cpufreq_policy *policy,
 319                                         unsigned int target_freq,
 320                                         unsigned int relation)
 321 {
 322         unsigned int    newstate = 0;
 323
 324         if (cpufreq_frequency_table_target(policy, pmac_cpu_freqs,
 325                         target_freq, relation, &newstate))
 326                 return -EINVAL;
 327
 328         return do_set_cpu_speed(newstate);
 329 }
 330
 331 unsigned int __pmac pmac_get_one_cpufreq(int i)
 332 {
 333         /* Supports only one CPU for now */
 334         return (i == 0) ? cur_freq : 0;
 335 }
 336
 337 static int __pmac pmac_cpufreq_cpu_init(struct cpufreq_policy *policy)
 338 {
 339         if (policy->cpu != 0)
 340                 return -ENODEV;
 341
 342         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 343         policy->cpuinfo.transition_latency      = CPUFREQ_ETERNAL;
 344         policy->cur = cur_freq;
 345
 346         return cpufreq_frequency_table_cpuinfo(policy, &pmac_cpu_freqs[0]);
 347 }
 348
 349 static u32 __pmac read_gpio(struct device_node *np)
 350 {
 351         u32 *reg = (u32 *)get_property(np, "reg", NULL);
 352
 353         if (reg == NULL)
 354                 return 0;
 355         /* That works for all keylargos but shall be fixed properly
 356          * some day...
 357          */
 358         return 0x50 + (*reg);
 359 }
 360
 361 static struct cpufreq_driver pmac_cpufreq_driver = {
 362         .verify         = pmac_cpufreq_verify,
 363         .target         = pmac_cpufreq_target,
 364         .init           = pmac_cpufreq_cpu_init,
 365         .name           = "powermac",
 366         .owner          = THIS_MODULE,
 367 };
 368
 369
 370 static int __pmac pmac_cpufreq_init_MacRISC3(struct device_node *cpunode)
 371 {
 372         struct device_node *volt_gpio_np = of_find_node_by_name(NULL,
 373                                                                 "voltage-gpio");
 374         struct device_node *freq_gpio_np = of_find_node_by_name(NULL,
 375                                                                 "frequency-gpio");
 376         struct device_node *slew_done_gpio_np = of_find_node_by_name(NULL,
 377                                                                      "slewing-done");
 378         u32 *value;
 379
 380         /*
 381          * Check to see if it's GPIO driven or PMU only
 382          *
 383          * The way we extract the GPIO address is slightly hackish, but it
 384          * works well enough for now. We need to abstract the whole GPIO
 385          * stuff sooner or later anyway
 386          */
 387
 388         if (volt_gpio_np)
 389                 voltage_gpio = read_gpio(volt_gpio_np);
 390         if (freq_gpio_np)
 391                 frequency_gpio = read_gpio(freq_gpio_np);
 392         if (slew_done_gpio_np)
 393                 slew_done_gpio = read_gpio(slew_done_gpio_np);
 394
 395         /* If we use the frequency GPIOs, calculate the min/max speeds based
 396          * on the bus frequencies
 397          */
 398         if (frequency_gpio && slew_done_gpio) {
 399                 int lenp, rc;
 400                 u32 *freqs, *ratio;
 401
 402                 freqs = (u32 *)get_property(cpunode, "bus-frequencies", &lenp);
 403                 lenp /= sizeof(u32);
 404                 if (freqs == NULL || lenp != 2) {
 405                         printk(KERN_ERR "cpufreq: bus-frequencies incorrect or missing\n");
 406                         return 1;
 407                 }
 408                 ratio = (u32 *)get_property(cpunode, "processor-to-bus-ratio*2", NULL);
 409                 if (ratio == NULL) {
 410                         printk(KERN_ERR "cpufreq: processor-to-bus-ratio*2 missing\n");
 411                         return 1;
 412                 }
 413
 414                 /* Get the min/max bus frequencies */
 415                 low_freq = min(freqs[0], freqs[1]);
 416                 hi_freq = max(freqs[0], freqs[1]);
 417
 418                 /* Grrrr.. It _seems_ that the device-tree is lying on the low bus
 419                  * frequency, it claims it to be around 84Mhz on some models while
 420                  * it appears to be approx. 101Mhz on all. Let's hack around here...
 421                  * fortunately, we don't need to be too precise
 422                  */
 423                 if (low_freq < 98000000)
 424                         low_freq = 101000000;
 425
 426                 /* Convert those to CPU core clocks */
 427                 low_freq = (low_freq * (*ratio)) / 2000;
 428                 hi_freq = (hi_freq * (*ratio)) / 2000;
 429
 430                 /* Now we get the frequencies, we read the GPIO to see what is out current
 431                  * speed
 432                  */
 433                 rc = pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, frequency_gpio, 0);
 434                 cur_freq = (rc & 0x01) ? hi_freq : low_freq;
 435
 436                 set_speed_proc = gpios_set_cpu_speed;
 437                 return 1;
 438         }
 439
 440         /* If we use the PMU, look for the min & max frequencies in the
 441          * device-tree
 442          */
 443         value = (u32 *)get_property(cpunode, "min-clock-frequency", NULL);
 444         if (!value)
 445                 return 1;
 446         low_freq = (*value) / 1000;
 447         /* The PowerBook G4 12" (PowerBook6,1) has an error in the device-tree
 448          * here */
 449         if (low_freq < 100000)
 450                 low_freq *= 10;
 451
 452         value = (u32 *)get_property(cpunode, "max-clock-frequency", NULL);
 453         if (!value)
 454                 return 1;
 455         hi_freq = (*value) / 1000;
 456         set_speed_proc = pmu_set_cpu_speed;
 457
 458         return 0;
 459 }
 460
 461 static int __pmac pmac_cpufreq_init_7447A(struct device_node *cpunode)
 462 {
 463         struct device_node *volt_gpio_np;
 464         u32 *reg;
 465         struct cpufreq_driver *driver = &pmac_cpufreq_driver;
 466
 467         /* OF only reports the high frequency */
 468         hi_freq = cur_freq;
 469         low_freq = cur_freq/2;
 470         driver->get = dfs_get_cpu_speed;
 471         cur_freq = driver->get(0);
 472
 473         volt_gpio_np = of_find_node_by_name(NULL, "cpu-vcore-select");
 474         if (!volt_gpio_np){
 475                 printk(KERN_ERR "cpufreq: missing cpu-vcore-select gpio\n");
 476                 return 1;
 477         }
 478
 479         reg = (u32 *)get_property(volt_gpio_np, "reg", NULL);
 480         voltage_gpio = *reg;
 481         set_speed_proc = dfs_set_cpu_speed;
 482
 483         return 0;
 484 }
 485
 486 /* Currently, we support the following machines:
 487  *
 488  *  - Titanium PowerBook 1Ghz (PMU based, 667Mhz & 1Ghz)
 489  *  - Titanium PowerBook 800 (PMU based, 667Mhz & 800Mhz)
 490  *  - Titanium PowerBook 400 (PMU based, 300Mhz & 400Mhz)
 491  *  - Titanium PowerBook 500 (PMU based, 300Mhz & 500Mhz)
 492  *  - iBook2 500/600 (PMU based, 400Mhz & 500/600Mhz)
 493  *  - iBook2 700 (CPU based, 400Mhz & 700Mhz, support low voltage)
 494  *  - Recent MacRISC3 laptops
 495  *  - iBook G4s and PowerBook G4s with 7447A CPUs
 496  */
 497 static int __init pmac_cpufreq_setup(void)
 498 {
 499         struct device_node      *cpunode;
 500         u32                     *value;
 501
 502         if (strstr(cmd_line, "nocpufreq"))
 503                 return 0;
 504
 505         /* Assume only one CPU */
 506         cpunode = find_type_devices("cpu");
 507         if (!cpunode)
 508                 goto out;
 509
 510         /* Get current cpu clock freq */
 511         value = (u32 *)get_property(cpunode, "clock-frequency", NULL);
 512         if (!value)
 513                 goto out;
 514         cur_freq = (*value) / 1000;
 515
 516         /*  Check for 7447A based iBook G4 or PowerBook */
 517         if (machine_is_compatible("PowerBook6,5") ||
 518             machine_is_compatible("PowerBook6,4") ||
 519             machine_is_compatible("PowerBook5,5") ||
 520             machine_is_compatible("PowerBook5,4")) {
 521                 pmac_cpufreq_init_7447A(cpunode);
 522         /* Check for other MacRISC3 machines */
 523         } else if (machine_is_compatible("PowerBook3,4") ||
 524                    machine_is_compatible("PowerBook3,5") ||
 525                    machine_is_compatible("MacRISC3")) {
 526                 pmac_cpufreq_init_MacRISC3(cpunode);
 527         /* Else check for iBook2 500/600 */
 528         } else if (machine_is_compatible("PowerBook4,1")) {
 529                 hi_freq = cur_freq;
 530                 low_freq = 400000;
 531                 set_speed_proc = pmu_set_cpu_speed;
 532         }
 533         /* Else check for TiPb 400 & 500 */
 534         else if (machine_is_compatible("PowerBook3,2")) {
 535                 /* We only know about the 400 MHz and the 500Mhz model
 536                  * they both have 300 MHz as low frequency
 537                  */
 538                 if (cur_freq < 350000 || cur_freq > 550000)
 539                         goto out;
 540                 hi_freq = cur_freq;
 541                 low_freq = 300000;
 542                 set_speed_proc = pmu_set_cpu_speed;
 543         }
 544         /* Else check for 750FX */
 545         else if (PVR_VER(mfspr(PVR)) == 0x7000) {
 546                 if (get_property(cpunode, "dynamic-power-step", NULL) == NULL)
 547                         goto out;
 548                 hi_freq = cur_freq;
 549                 value = (u32 *)get_property(cpunode, "reduced-clock-frequency", NULL);
 550                 if (!value)
 551                         goto out;
 552                 low_freq = (*value) / 1000;
 553                 set_speed_proc = cpu_750fx_cpu_speed;
 554         }
 555 out:
 556         if (set_speed_proc == NULL)
 557                 return -ENODEV;
 558
 559         pmac_cpu_freqs[CPUFREQ_LOW].frequency = low_freq;
 560         pmac_cpu_freqs[CPUFREQ_HIGH].frequency = hi_freq;
 561
 562         printk(KERN_INFO "Registering PowerMac CPU frequency driver\n");
 563         printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Boot: %d Mhz\n",
 564                low_freq/1000, hi_freq/1000, cur_freq/1000);
 565
 566         return cpufreq_register_driver(&pmac_cpufreq_driver);
 567 }
 568
 569 module_init(pmac_cpufreq_setup);
 570