arch/ppc/platforms/pmac_cpufreq.c

   1 /*
   2  *  arch/ppc/platforms/pmac_cpufreq.c
   3  *
   4  *  Copyright (C) 2002 - 2003 Benjamin Herrenschmidt <benh@kernel.crashing.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  */
  11
  12 #include <linux/config.h>
  13 #include <linux/module.h>
  14 #include <linux/types.h>
  15 #include <linux/errno.h>
  16 #include <linux/kernel.h>
  17 #include <linux/delay.h>
  18 #include <linux/sched.h>
  19 #include <linux/adb.h>
  20 #include <linux/pmu.h>
  21 #include <linux/slab.h>
  22 #include <linux/cpufreq.h>
  23 #include <linux/init.h>
  24 #include <linux/sysdev.h>
  25 #include <linux/i2c.h>
  26 #include <asm/prom.h>
  27 #include <asm/machdep.h>
  28 #include <asm/irq.h>
  29 #include <asm/hardirq.h>
  30 #include <asm/pmac_feature.h>
  31 #include <asm/mmu_context.h>
  32 #include <asm/sections.h>
  33 #include <asm/cputable.h>
  34 #include <asm/time.h>
  35
  36 /* WARNING !!! This will cause calibrate_delay() to be called,
  37  * but this is an __init function ! So you MUST go edit
  38  * init/main.c to make it non-init before enabling DEBUG_FREQ
  39  */
  40 #undef DEBUG_FREQ
  41
  42 /*
  43  * There is a problem with the core cpufreq code on SMP kernels,
  44  * it won't recalculate the Bogomips properly
  45  */
  46 #ifdef CONFIG_SMP
  47 #warning "WARNING, CPUFREQ not recommended on SMP kernels"
  48 #endif
  49
  50 extern void low_choose_750fx_pll(int pll);
  51 extern void low_sleep_handler(void);
  52 extern void openpic_suspend(struct sys_device *sysdev, u32 state);
  53 extern void openpic_resume(struct sys_device *sysdev);
  54 extern void enable_kernel_altivec(void);
  55 extern void enable_kernel_fp(void);
  56
  57 static unsigned int low_freq;
  58 static unsigned int hi_freq;
  59 static unsigned int cur_freq;
  60
  61 /* Clean that up some day ... use a func ptr or at least an enum... */
  62 static int cpufreq_uses_pmu;
  63 static int cpufreq_uses_gpios;
  64
  65 static u32 voltage_gpio;
  66 static u32 frequency_gpio;
  67 static u32 slew_done_gpio;
  68
  69 #define PMAC_CPU_LOW_SPEED      1
  70 #define PMAC_CPU_HIGH_SPEED     0
  71
  72 /* There are only two frequency states for each processor. Values
  73  * are in kHz for the time being.
  74  */
  75 #define CPUFREQ_HIGH                  PMAC_CPU_HIGH_SPEED
  76 #define CPUFREQ_LOW                   PMAC_CPU_LOW_SPEED
  77
  78 static struct cpufreq_frequency_table pmac_cpu_freqs[] = {
  79         {CPUFREQ_HIGH,          0},
  80         {CPUFREQ_LOW,           0},
  81         {0,                     CPUFREQ_TABLE_END},
  82 };
  83
  84 static inline void wakeup_decrementer(void)
  85 {
  86         set_dec(tb_ticks_per_jiffy);
  87         /* No currently-supported powerbook has a 601,
  88          * so use get_tbl, not native
  89          */
  90         last_jiffy_stamp(0) = tb_last_stamp = get_tbl();
  91 }
  92
  93 #ifdef DEBUG_FREQ
  94 static inline void debug_calc_bogomips(void)
  95 {
  96         /* This will cause a recalc of bogomips and display the
  97          * result. We backup/restore the value to avoid affecting the
  98          * core cpufreq framework's own calculation.
  99          */
 100         extern void calibrate_delay(void);
 101
 102         unsigned long save_lpj = loops_per_jiffy;
 103         calibrate_delay();
 104         loops_per_jiffy = save_lpj;
 105 }
 106 #endif /* DEBUG_FREQ */
 107
 108 /* Switch CPU speed under 750FX CPU control
 109  */
 110 static int __pmac cpu_750fx_cpu_speed(int low_speed)
 111 {
 112 #ifdef DEBUG_FREQ
 113         printk(KERN_DEBUG "HID1, before: %x\n", mfspr(SPRN_HID1));
 114 #endif
 115 #ifdef CONFIG_6xx
 116         low_choose_750fx_pll(low_speed);
 117 #endif
 118 #ifdef DEBUG_FREQ
 119         printk(KERN_DEBUG "HID1, after: %x\n", mfspr(SPRN_HID1));
 120         debug_calc_bogomips();
 121 #endif
 122
 123         return 0;
 124 }
 125
 126 /* Switch CPU speed using slewing GPIOs
 127  */
 128 static int __pmac gpios_set_cpu_speed(unsigned int low_speed)
 129 {
 130         int gpio;
 131
 132         /* If ramping up, set voltage first */
 133         if (low_speed == 0) {
 134                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x05);
 135                 /* Delay is way too big but it's ok, we schedule */
 136                 set_current_state(TASK_UNINTERRUPTIBLE);
 137                 schedule_timeout(HZ/100);
 138         }
 139
 140         /* Set frequency */
 141         pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, frequency_gpio, low_speed ? 0x04 : 0x05);
 142         udelay(200);
 143         do {
 144                 set_current_state(TASK_UNINTERRUPTIBLE);
 145                 schedule_timeout(1);
 146                 gpio = pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, slew_done_gpio, 0);
 147         } while((gpio & 0x02) == 0);
 148
 149         /* If ramping down, set voltage last */
 150         if (low_speed == 1) {
 151                 pmac_call_feature(PMAC_FTR_WRITE_GPIO, NULL, voltage_gpio, 0x04);
 152                 /* Delay is way too big but it's ok, we schedule */
 153                 set_current_state(TASK_UNINTERRUPTIBLE);
 154                 schedule_timeout(HZ/100);
 155         }
 156
 157 #ifdef DEBUG_FREQ
 158         debug_calc_bogomips();
 159 #endif
 160
 161         return 0;
 162 }
 163
 164 /* Switch CPU speed under PMU control
 165  */
 166 static int __pmac pmu_set_cpu_speed(unsigned int low_speed)
 167 {
 168         struct adb_request req;
 169         unsigned long save_l2cr;
 170         unsigned long save_l3cr;
 171
 172         preempt_disable();
 173
 174 #ifdef DEBUG_FREQ
 175         printk(KERN_DEBUG "HID1, before: %x\n", mfspr(SPRN_HID1));
 176 #endif
 177         /* Disable all interrupt sources on openpic */
 178         openpic_suspend(NULL, 1);
 179
 180         /* Make sure the decrementer won't interrupt us */
 181         asm volatile("mtdec %0" : : "r" (0x7fffffff));
 182         /* Make sure any pending DEC interrupt occuring while we did
 183          * the above didn't re-enable the DEC */
 184         mb();
 185         asm volatile("mtdec %0" : : "r" (0x7fffffff));
 186
 187         /* We can now disable MSR_EE */
 188         local_irq_disable();
 189
 190         /* Giveup the FPU & vec */
 191         enable_kernel_fp();
 192
 193 #ifdef CONFIG_ALTIVEC
 194         if (cur_cpu_spec[0]->cpu_features & CPU_FTR_ALTIVEC)
 195                 enable_kernel_altivec();
 196 #endif /* CONFIG_ALTIVEC */
 197
 198         /* Save & disable L2 and L3 caches */
 199         save_l3cr = _get_L3CR();        /* (returns -1 if not available) */
 200         save_l2cr = _get_L2CR();        /* (returns -1 if not available) */
 201         if (save_l3cr != 0xffffffff && (save_l3cr & L3CR_L3E) != 0)
 202                 _set_L3CR(save_l3cr & 0x7fffffff);
 203         if (save_l2cr != 0xffffffff && (save_l2cr & L2CR_L2E) != 0)
 204                 _set_L2CR(save_l2cr & 0x7fffffff);
 205
 206         /* Send the new speed command. My assumption is that this command
 207          * will cause PLL_CFG[0..3] to be changed next time CPU goes to sleep
 208          */
 209         pmu_request(&req, NULL, 6, PMU_CPU_SPEED, 'W', 'O', 'O', 'F', low_speed);
 210         while (!req.complete)
 211                 pmu_poll();
 212
 213         /* Prepare the northbridge for the speed transition */
 214         pmac_call_feature(PMAC_FTR_SLEEP_STATE,NULL,1,1);
 215
 216         /* Call low level code to backup CPU state and recover from
 217          * hardware reset
 218          */
 219         low_sleep_handler();
 220
 221         /* Restore the northbridge */
 222         pmac_call_feature(PMAC_FTR_SLEEP_STATE,NULL,1,0);
 223
 224         /* Restore L2 cache */
 225         if (save_l2cr != 0xffffffff && (save_l2cr & L2CR_L2E) != 0)
 226                 _set_L2CR(save_l2cr);
 227         /* Restore L3 cache */
 228         if (save_l3cr != 0xffffffff && (save_l3cr & L3CR_L3E) != 0)
 229                 _set_L3CR(save_l3cr);
 230
 231         /* Restore userland MMU context */
 232         set_context(current->active_mm->context, current->active_mm->pgd);
 233
 234 #ifdef DEBUG_FREQ
 235         printk(KERN_DEBUG "HID1, after: %x\n", mfspr(SPRN_HID1));
 236 #endif
 237
 238         /* Restore low level PMU operations */
 239         pmu_unlock();
 240
 241         /* Restore decrementer */
 242         wakeup_decrementer();
 243
 244         /* Restore interrupts */
 245         openpic_resume(NULL);
 246
 247         /* Let interrupts flow again ... */
 248         local_irq_enable();
 249
 250 #ifdef DEBUG_FREQ
 251         debug_calc_bogomips();
 252 #endif
 253
 254         preempt_enable();
 255
 256         return 0;
 257 }
 258
 259 static int __pmac do_set_cpu_speed(int speed_mode)
 260 {
 261         struct cpufreq_freqs freqs;
 262         int rc;
 263
 264         freqs.old = cur_freq;
 265         freqs.new = (speed_mode == PMAC_CPU_HIGH_SPEED) ? hi_freq : low_freq;
 266         freqs.cpu = smp_processor_id();
 267
 268         if (freqs.old == freqs.new)
 269                 return 0;
 270
 271         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 272         if (cpufreq_uses_pmu)
 273                 rc = pmu_set_cpu_speed(speed_mode);
 274         else if (cpufreq_uses_gpios)
 275                 rc = gpios_set_cpu_speed(speed_mode);
 276         else
 277                 rc = cpu_750fx_cpu_speed(speed_mode);
 278         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 279         cur_freq = (speed_mode == PMAC_CPU_HIGH_SPEED) ? hi_freq : low_freq;
 280
 281         return rc;
 282 }
 283
 284 static int __pmac pmac_cpufreq_verify(struct cpufreq_policy *policy)
 285 {
 286         return cpufreq_frequency_table_verify(policy, pmac_cpu_freqs);
 287 }
 288
 289 static int __pmac pmac_cpufreq_target(  struct cpufreq_policy *policy,
 290                                         unsigned int target_freq,
 291                                         unsigned int relation)
 292 {
 293         unsigned int    newstate = 0;
 294
 295         if (cpufreq_frequency_table_target(policy, pmac_cpu_freqs,
 296                         target_freq, relation, &newstate))
 297                 return -EINVAL;
 298
 299         return do_set_cpu_speed(newstate);
 300 }
 301
 302 unsigned int __pmac pmac_get_one_cpufreq(int i)
 303 {
 304         /* Supports only one CPU for now */
 305         return (i == 0) ? cur_freq : 0;
 306 }
 307
 308 static int __pmac pmac_cpufreq_cpu_init(struct cpufreq_policy *policy)
 309 {
 310         if (policy->cpu != 0)
 311                 return -ENODEV;
 312
 313         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 314         policy->cpuinfo.transition_latency      = CPUFREQ_ETERNAL;
 315         policy->cur = cur_freq;
 316
 317         return cpufreq_frequency_table_cpuinfo(policy, &pmac_cpu_freqs[0]);
 318 }
 319
 320 static u32 __pmac read_gpio(struct device_node *np)
 321 {
 322         u32 *reg = (u32 *)get_property(np, "reg", NULL);
 323
 324         if (reg == NULL)
 325                 return 0;
 326         /* That works for all keylargos but shall be fixed properly
 327          * some day...
 328          */
 329         return 0x50 + (*reg);
 330 }
 331
 332 static struct cpufreq_driver pmac_cpufreq_driver = {
 333         .verify         = pmac_cpufreq_verify,
 334         .target         = pmac_cpufreq_target,
 335         .init           = pmac_cpufreq_cpu_init,
 336         .name           = "powermac",
 337         .owner          = THIS_MODULE,
 338 };
 339
 340
 341 /* Currently, we support the following machines:
 342  *
 343  *  - Titanium PowerBook 1Ghz (PMU based, 667Mhz & 1Ghz)
 344  *  - Titanium PowerBook 800 (PMU based, 667Mhz & 800Mhz)
 345  *  - Titanium PowerBook 500 (PMU based, 300Mhz & 500Mhz)
 346  *  - iBook2 500 (PMU based, 400Mhz & 500Mhz)
 347  *  - iBook2 700 (CPU based, 400Mhz & 700Mhz, support low voltage)
 348  *  - Recent MacRISC3 machines
 349  */
 350 static int __init pmac_cpufreq_setup(void)
 351 {
 352         struct device_node      *cpunode;
 353         u32                     *value;
 354         int                     has_freq_ctl = 0;
 355
 356         if (strstr(cmd_line, "nocpufreq"))
 357                 return 0;
 358
 359         /* Assume only one CPU */
 360         cpunode = find_type_devices("cpu");
 361         if (!cpunode)
 362                 goto out;
 363
 364         /* Get current cpu clock freq */
 365         value = (u32 *)get_property(cpunode, "clock-frequency", NULL);
 366         if (!value)
 367                 goto out;
 368         cur_freq = (*value) / 1000;
 369
 370         /* Check for newer machines */
 371         if (machine_is_compatible("PowerBook3,4") ||
 372             machine_is_compatible("PowerBook3,5") ||
 373             machine_is_compatible("MacRISC3")) {
 374                 struct device_node *volt_gpio_np = of_find_node_by_name(NULL, "voltage-gpio");
 375                 struct device_node *freq_gpio_np = of_find_node_by_name(NULL, "frequency-gpio");
 376                 struct device_node *slew_done_gpio_np = of_find_node_by_name(NULL, "slewing-done");
 377
 378                 /*
 379                  * Check to see if it's GPIO driven or PMU only
 380                  *
 381                  * The way we extract the GPIO address is slightly hackish, but it
 382                  * works well enough for now. We need to abstract the whole GPIO
 383                  * stuff sooner or later anyway
 384                  */
 385
 386                 if (volt_gpio_np)
 387                         voltage_gpio = read_gpio(volt_gpio_np);
 388                 if (freq_gpio_np)
 389                         frequency_gpio = read_gpio(freq_gpio_np);
 390                 if (slew_done_gpio_np)
 391                         slew_done_gpio = read_gpio(slew_done_gpio_np);
 392
 393                 /* If we use the frequency GPIOs, calculate the min/max speeds based
 394                  * on the bus frequencies
 395                  */
 396                 if (frequency_gpio && slew_done_gpio) {
 397                         int lenp, rc;
 398                         u32 *freqs, *ratio;
 399
 400                         freqs = (u32 *)get_property(cpunode, "bus-frequencies", &lenp);
 401                         lenp /= sizeof(u32);
 402                         if (freqs == NULL || lenp != 2) {
 403                                 printk(KERN_ERR "cpufreq: bus-frequencies incorrect or missing\n");
 404                                 goto out;
 405                         }
 406                         ratio = (u32 *)get_property(cpunode, "processor-to-bus-ratio*2", NULL);
 407                         if (ratio == NULL) {
 408                                 printk(KERN_ERR "cpufreq: processor-to-bus-ratio*2 missing\n");
 409                                 goto out;
 410                         }
 411
 412                         /* Get the min/max bus frequencies */
 413                         low_freq = min(freqs[0], freqs[1]);
 414                         hi_freq = max(freqs[0], freqs[1]);
 415
 416                         /* Grrrr.. It _seems_ that the device-tree is lying on the low bus
 417                          * frequency, it claims it to be around 84Mhz on some models while
 418                          * it appears to be approx. 101Mhz on all. Let's hack around here...
 419                          * fortunately, we don't need to be too precise
 420                          */
 421                         if (low_freq < 98000000)
 422                                 low_freq = 101000000;
 423
 424                         /* Convert those to CPU core clocks */
 425                         low_freq = (low_freq * (*ratio)) / 2000;
 426                         hi_freq = (hi_freq * (*ratio)) / 2000;
 427
 428                         /* Now we get the frequencies, we read the GPIO to see what is out current
 429                          * speed
 430                          */
 431                         rc = pmac_call_feature(PMAC_FTR_READ_GPIO, NULL, frequency_gpio, 0);
 432                         cur_freq = (rc & 0x01) ? hi_freq : low_freq;
 433
 434                         has_freq_ctl = 1;
 435                         cpufreq_uses_gpios = 1;
 436                         goto out;
 437                 }
 438
 439                 /* If we use the PMU, look for the min & max frequencies in the
 440                  * device-tree
 441                  */
 442                 value = (u32 *)get_property(cpunode, "min-clock-frequency", NULL);
 443                 if (!value)
 444                         goto out;
 445                 low_freq = (*value) / 1000;
 446                 /* The PowerBook G4 12" (PowerBook6,1) has an error in the device-tree
 447                  * here */
 448                 if (low_freq < 100000)
 449                         low_freq *= 10;
 450
 451                 value = (u32 *)get_property(cpunode, "max-clock-frequency", NULL);
 452                 if (!value)
 453                         goto out;
 454                 hi_freq = (*value) / 1000;
 455                 has_freq_ctl = 1;
 456                 cpufreq_uses_pmu = 1;
 457         }
 458         /* Else check for iBook2 500 */
 459         else if (machine_is_compatible("PowerBook4,1")) {
 460                 /* We only know about 500Mhz model */
 461                 if (cur_freq < 450000 || cur_freq > 550000)
 462                         goto out;
 463                 hi_freq = cur_freq;
 464                 low_freq = 400000;
 465                 has_freq_ctl = 1;
 466                 cpufreq_uses_pmu = 1;
 467         }
 468         /* Else check for TiPb 500 */
 469         else if (machine_is_compatible("PowerBook3,2")) {
 470                 /* We only know about 500Mhz model */
 471                 if (cur_freq < 450000 || cur_freq > 550000)
 472                         goto out;
 473                 hi_freq = cur_freq;
 474                 low_freq = 300000;
 475                 has_freq_ctl = 1;
 476                 cpufreq_uses_pmu = 1;
 477         }
 478         /* Else check for 750FX */
 479         else if (PVR_VER(mfspr(PVR)) == 0x7000) {
 480                 if (get_property(cpunode, "dynamic-power-step", NULL) == NULL)
 481                         goto out;
 482                 hi_freq = cur_freq;
 483                 value = (u32 *)get_property(cpunode, "reduced-clock-frequency", NULL);
 484                 if (!value)
 485                         goto out;
 486                 low_freq = (*value) / 1000;
 487                 cpufreq_uses_pmu = 0;
 488                 has_freq_ctl = 1;
 489         }
 490 out:
 491         if (!has_freq_ctl)
 492                 return -ENODEV;
 493
 494         pmac_cpu_freqs[CPUFREQ_LOW].frequency = low_freq;
 495         pmac_cpu_freqs[CPUFREQ_HIGH].frequency = hi_freq;
 496
 497         printk(KERN_INFO "Registering PowerMac CPU frequency driver\n");
 498         printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Boot: %d Mhz, switch method: %s\n",
 499                low_freq/1000, hi_freq/1000, cur_freq/1000,
 500                cpufreq_uses_pmu ? "PMU" : (cpufreq_uses_gpios ? "GPIOs" : "CPU"));
 501
 502         return cpufreq_register_driver(&pmac_cpufreq_driver);
 503 }
 504
 505 module_init(pmac_cpufreq_setup);
 506