drivers/cpufreq/longhaul.c

   1 /*
   2  *  (C) 2001-2004  Dave Jones. <davej@redhat.com>
   3  *  (C) 2002  Padraig Brady. <padraig@antefacto.com>
   4  *
   5  *  Licensed under the terms of the GNU GPL License version 2.
   6  *  Based upon datasheets & sample CPUs kindly provided by VIA.
   7  *
   8  *  VIA have currently 3 different versions of Longhaul.
   9  *  Version 1 (Longhaul) uses the BCR2 MSR at 0x1147.
  10  *   It is present only in Samuel 1 (C5A), Samuel 2 (C5B) stepping 0.
  11  *  Version 2 of longhaul is backward compatible with v1, but adds
  12  *   LONGHAUL MSR for purpose of both frequency and voltage scaling.
  13  *   Present in Samuel 2 (steppings 1-7 only) (C5B), and Ezra (C5C).
  14  *  Version 3 of longhaul got renamed to Powersaver and redesigned
  15  *   to use only the POWERSAVER MSR at 0x110a.
  16  *   It is present in Ezra-T (C5M), Nehemiah (C5X) and above.
  17  *   It's pretty much the same feature wise to longhaul v2, though
  18  *   there is provision for scaling FSB too, but this doesn't work
  19  *   too well in practice so we don't even try to use this.
  20  *
  21  *  BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
  22  */
  23
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/moduleparam.h>
  27 #include <linux/init.h>
  28 #include <linux/cpufreq.h>
  29 #include <linux/pci.h>
  30 #include <linux/slab.h>
  31 #include <linux/string.h>
  32 #include <linux/delay.h>
  33 #include <linux/timex.h>
  34 #include <linux/io.h>
  35 #include <linux/acpi.h>
  36
  37 #include <asm/msr.h>
  38 #include <asm/cpu_device_id.h>
  39 #include <acpi/processor.h>
  40
  41 #include "longhaul.h"
  42
  43 #define PFX "longhaul: "
  44
  45 #define TYPE_LONGHAUL_V1        1
  46 #define TYPE_LONGHAUL_V2        2
  47 #define TYPE_POWERSAVER         3
  48
  49 #define CPU_SAMUEL      1
  50 #define CPU_SAMUEL2     2
  51 #define CPU_EZRA        3
  52 #define CPU_EZRA_T      4
  53 #define CPU_NEHEMIAH    5
  54 #define CPU_NEHEMIAH_C  6
  55
  56 /* Flags */
  57 #define USE_ACPI_C3             (1 << 1)
  58 #define USE_NORTHBRIDGE         (1 << 2)
  59
  60 static int cpu_model;
  61 static unsigned int numscales = 16;
  62 static unsigned int fsb;
  63
  64 static const struct mV_pos *vrm_mV_table;
  65 static const unsigned char *mV_vrm_table;
  66
  67 static unsigned int highest_speed, lowest_speed; /* kHz */
  68 static unsigned int minmult, maxmult;
  69 static int can_scale_voltage;
  70 static struct acpi_processor *pr;
  71 static struct acpi_processor_cx *cx;
  72 static u32 acpi_regs_addr;
  73 static u8 longhaul_flags;
  74 static unsigned int longhaul_index;
  75
  76 /* Module parameters */
  77 static int scale_voltage;
  78 static int disable_acpi_c3;
  79 static int revid_errata;
  80 static int enable;
  81
  82 /* Clock ratios multiplied by 10 */
  83 static int mults[32];
  84 static int eblcr[32];
  85 static int longhaul_version;
  86 static struct cpufreq_frequency_table *longhaul_table;
  87
  88 static char speedbuffer[8];
  89
  90 static char *print_speed(int speed)
  91 {
  92         if (speed < 1000) {
  93                 snprintf(speedbuffer, sizeof(speedbuffer), "%dMHz", speed);
  94                 return speedbuffer;
  95         }
  96
  97         if (speed%1000 == 0)
  98                 snprintf(speedbuffer, sizeof(speedbuffer),
  99                         "%dGHz", speed/1000);
 100         else
 101                 snprintf(speedbuffer, sizeof(speedbuffer),
 102                         "%d.%dGHz", speed/1000, (speed%1000)/100);
 103
 104         return speedbuffer;
 105 }
 106
 107
 108 static unsigned int calc_speed(int mult)
 109 {
 110         int khz;
 111         khz = (mult/10)*fsb;
 112         if (mult%10)
 113                 khz += fsb/2;
 114         khz *= 1000;
 115         return khz;
 116 }
 117
 118
 119 static int longhaul_get_cpu_mult(void)
 120 {
 121         unsigned long invalue = 0, lo, hi;
 122
 123         rdmsr(MSR_IA32_EBL_CR_POWERON, lo, hi);
 124         invalue = (lo & (1<<22|1<<23|1<<24|1<<25))>>22;
 125         if (longhaul_version == TYPE_LONGHAUL_V2 ||
 126             longhaul_version == TYPE_POWERSAVER) {
 127                 if (lo & (1<<27))
 128                         invalue += 16;
 129         }
 130         return eblcr[invalue];
 131 }
 132
 133 /* For processor with BCR2 MSR */
 134
 135 static void do_longhaul1(unsigned int mults_index)
 136 {
 137         union msr_bcr2 bcr2;
 138
 139         rdmsrl(MSR_VIA_BCR2, bcr2.val);
 140         /* Enable software clock multiplier */
 141         bcr2.bits.ESOFTBF = 1;
 142         bcr2.bits.CLOCKMUL = mults_index & 0xff;
 143
 144         /* Sync to timer tick */
 145         safe_halt();
 146         /* Change frequency on next halt or sleep */
 147         wrmsrl(MSR_VIA_BCR2, bcr2.val);
 148         /* Invoke transition */
 149         ACPI_FLUSH_CPU_CACHE();
 150         halt();
 151
 152         /* Disable software clock multiplier */
 153         local_irq_disable();
 154         rdmsrl(MSR_VIA_BCR2, bcr2.val);
 155         bcr2.bits.ESOFTBF = 0;
 156         wrmsrl(MSR_VIA_BCR2, bcr2.val);
 157 }
 158
 159 /* For processor with Longhaul MSR */
 160
 161 static void do_powersaver(int cx_address, unsigned int mults_index,
 162                           unsigned int dir)
 163 {
 164         union msr_longhaul longhaul;
 165         u32 t;
 166
 167         rdmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 168         /* Setup new frequency */
 169         if (!revid_errata)
 170                 longhaul.bits.RevisionKey = longhaul.bits.RevisionID;
 171         else
 172                 longhaul.bits.RevisionKey = 0;
 173         longhaul.bits.SoftBusRatio = mults_index & 0xf;
 174         longhaul.bits.SoftBusRatio4 = (mults_index & 0x10) >> 4;
 175         /* Setup new voltage */
 176         if (can_scale_voltage)
 177                 longhaul.bits.SoftVID = (mults_index >> 8) & 0x1f;
 178         /* Sync to timer tick */
 179         safe_halt();
 180         /* Raise voltage if necessary */
 181         if (can_scale_voltage && dir) {
 182                 longhaul.bits.EnableSoftVID = 1;
 183                 wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 184                 /* Change voltage */
 185                 if (!cx_address) {
 186                         ACPI_FLUSH_CPU_CACHE();
 187                         halt();
 188                 } else {
 189                         ACPI_FLUSH_CPU_CACHE();
 190                         /* Invoke C3 */
 191                         inb(cx_address);
 192                         /* Dummy op - must do something useless after P_LVL3
 193                          * read */
 194                         t = inl(acpi_gbl_FADT.xpm_timer_block.address);
 195                 }
 196                 longhaul.bits.EnableSoftVID = 0;
 197                 wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 198         }
 199
 200         /* Change frequency on next halt or sleep */
 201         longhaul.bits.EnableSoftBusRatio = 1;
 202         wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 203         if (!cx_address) {
 204                 ACPI_FLUSH_CPU_CACHE();
 205                 halt();
 206         } else {
 207                 ACPI_FLUSH_CPU_CACHE();
 208                 /* Invoke C3 */
 209                 inb(cx_address);
 210                 /* Dummy op - must do something useless after P_LVL3 read */
 211                 t = inl(acpi_gbl_FADT.xpm_timer_block.address);
 212         }
 213         /* Disable bus ratio bit */
 214         longhaul.bits.EnableSoftBusRatio = 0;
 215         wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 216
 217         /* Reduce voltage if necessary */
 218         if (can_scale_voltage && !dir) {
 219                 longhaul.bits.EnableSoftVID = 1;
 220                 wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 221                 /* Change voltage */
 222                 if (!cx_address) {
 223                         ACPI_FLUSH_CPU_CACHE();
 224                         halt();
 225                 } else {
 226                         ACPI_FLUSH_CPU_CACHE();
 227                         /* Invoke C3 */
 228                         inb(cx_address);
 229                         /* Dummy op - must do something useless after P_LVL3
 230                          * read */
 231                         t = inl(acpi_gbl_FADT.xpm_timer_block.address);
 232                 }
 233                 longhaul.bits.EnableSoftVID = 0;
 234                 wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 235         }
 236 }
 237
 238 /**
 239  * longhaul_set_cpu_frequency()
 240  * @mults_index : bitpattern of the new multiplier.
 241  *
 242  * Sets a new clock ratio.
 243  */
 244
 245 static void longhaul_setstate(unsigned int table_index)
 246 {
 247         unsigned int mults_index;
 248         int speed, mult;
 249         struct cpufreq_freqs freqs;
 250         unsigned long flags;
 251         unsigned int pic1_mask, pic2_mask;
 252         u16 bm_status = 0;
 253         u32 bm_timeout = 1000;
 254         unsigned int dir = 0;
 255
 256         mults_index = longhaul_table[table_index].index;
 257         /* Safety precautions */
 258         mult = mults[mults_index & 0x1f];
 259         if (mult == -1)
 260                 return;
 261         speed = calc_speed(mult);
 262         if ((speed > highest_speed) || (speed < lowest_speed))
 263                 return;
 264         /* Voltage transition before frequency transition? */
 265         if (can_scale_voltage && longhaul_index < table_index)
 266                 dir = 1;
 267
 268         freqs.old = calc_speed(longhaul_get_cpu_mult());
 269         freqs.new = speed;
 270         freqs.cpu = 0; /* longhaul.c is UP only driver */
 271
 272         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 273
 274         pr_debug("Setting to FSB:%dMHz Mult:%d.%dx (%s)\n",
 275                         fsb, mult/10, mult%10, print_speed(speed/1000));
 276 retry_loop:
 277         preempt_disable();
 278         local_irq_save(flags);
 279
 280         pic2_mask = inb(0xA1);
 281         pic1_mask = inb(0x21);  /* works on C3. save mask. */
 282         outb(0xFF, 0xA1);       /* Overkill */
 283         outb(0xFE, 0x21);       /* TMR0 only */
 284
 285         /* Wait while PCI bus is busy. */
 286         if (acpi_regs_addr && (longhaul_flags & USE_NORTHBRIDGE
 287             || ((pr != NULL) && pr->flags.bm_control))) {
 288                 bm_status = inw(acpi_regs_addr);
 289                 bm_status &= 1 << 4;
 290                 while (bm_status && bm_timeout) {
 291                         outw(1 << 4, acpi_regs_addr);
 292                         bm_timeout--;
 293                         bm_status = inw(acpi_regs_addr);
 294                         bm_status &= 1 << 4;
 295                 }
 296         }
 297
 298         if (longhaul_flags & USE_NORTHBRIDGE) {
 299                 /* Disable AGP and PCI arbiters */
 300                 outb(3, 0x22);
 301         } else if ((pr != NULL) && pr->flags.bm_control) {
 302                 /* Disable bus master arbitration */
 303                 acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 1);
 304         }
 305         switch (longhaul_version) {
 306
 307         /*
 308          * Longhaul v1. (Samuel[C5A] and Samuel2 stepping 0[C5B])
 309          * Software controlled multipliers only.
 310          */
 311         case TYPE_LONGHAUL_V1:
 312                 do_longhaul1(mults_index);
 313                 break;
 314
 315         /*
 316          * Longhaul v2 appears in Samuel2 Steppings 1->7 [C5B] and Ezra [C5C]
 317          *
 318          * Longhaul v3 (aka Powersaver). (Ezra-T [C5M] & Nehemiah [C5N])
 319          * Nehemiah can do FSB scaling too, but this has never been proven
 320          * to work in practice.
 321          */
 322         case TYPE_LONGHAUL_V2:
 323         case TYPE_POWERSAVER:
 324                 if (longhaul_flags & USE_ACPI_C3) {
 325                         /* Don't allow wakeup */
 326                         acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
 327                         do_powersaver(cx->address, mults_index, dir);
 328                 } else {
 329                         do_powersaver(0, mults_index, dir);
 330                 }
 331                 break;
 332         }
 333
 334         if (longhaul_flags & USE_NORTHBRIDGE) {
 335                 /* Enable arbiters */
 336                 outb(0, 0x22);
 337         } else if ((pr != NULL) && pr->flags.bm_control) {
 338                 /* Enable bus master arbitration */
 339                 acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 0);
 340         }
 341         outb(pic2_mask, 0xA1);  /* restore mask */
 342         outb(pic1_mask, 0x21);
 343
 344         local_irq_restore(flags);
 345         preempt_enable();
 346
 347         freqs.new = calc_speed(longhaul_get_cpu_mult());
 348         /* Check if requested frequency is set. */
 349         if (unlikely(freqs.new != speed)) {
 350                 printk(KERN_INFO PFX "Failed to set requested frequency!\n");
 351                 /* Revision ID = 1 but processor is expecting revision key
 352                  * equal to 0. Jumpers at the bottom of processor will change
 353                  * multiplier and FSB, but will not change bits in Longhaul
 354                  * MSR nor enable voltage scaling. */
 355                 if (!revid_errata) {
 356                         printk(KERN_INFO PFX "Enabling \"Ignore Revision ID\" "
 357                                                 "option.\n");
 358                         revid_errata = 1;
 359                         msleep(200);
 360                         goto retry_loop;
 361                 }
 362                 /* Why ACPI C3 sometimes doesn't work is a mystery for me.
 363                  * But it does happen. Processor is entering ACPI C3 state,
 364                  * but it doesn't change frequency. I tried poking various
 365                  * bits in northbridge registers, but without success. */
 366                 if (longhaul_flags & USE_ACPI_C3) {
 367                         printk(KERN_INFO PFX "Disabling ACPI C3 support.\n");
 368                         longhaul_flags &= ~USE_ACPI_C3;
 369                         if (revid_errata) {
 370                                 printk(KERN_INFO PFX "Disabling \"Ignore "
 371                                                 "Revision ID\" option.\n");
 372                                 revid_errata = 0;
 373                         }
 374                         msleep(200);
 375                         goto retry_loop;
 376                 }
 377                 /* This shouldn't happen. Longhaul ver. 2 was reported not
 378                  * working on processors without voltage scaling, but with
 379                  * RevID = 1. RevID errata will make things right. Just
 380                  * to be 100% sure. */
 381                 if (longhaul_version == TYPE_LONGHAUL_V2) {
 382                         printk(KERN_INFO PFX "Switching to Longhaul ver. 1\n");
 383                         longhaul_version = TYPE_LONGHAUL_V1;
 384                         msleep(200);
 385                         goto retry_loop;
 386                 }
 387         }
 388         /* Report true CPU frequency */
 389         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 390
 391         if (!bm_timeout)
 392                 printk(KERN_INFO PFX "Warning: Timeout while waiting for "
 393                                 "idle PCI bus.\n");
 394 }
 395
 396 /*
 397  * Centaur decided to make life a little more tricky.
 398  * Only longhaul v1 is allowed to read EBLCR BSEL[0:1].
 399  * Samuel2 and above have to try and guess what the FSB is.
 400  * We do this by assuming we booted at maximum multiplier, and interpolate
 401  * between that value multiplied by possible FSBs and cpu_mhz which
 402  * was calculated at boot time. Really ugly, but no other way to do this.
 403  */
 404
 405 #define ROUNDING        0xf
 406
 407 static int guess_fsb(int mult)
 408 {
 409         int speed = cpu_khz / 1000;
 410         int i;
 411         int speeds[] = { 666, 1000, 1333, 2000 };
 412         int f_max, f_min;
 413
 414         for (i = 0; i < 4; i++) {
 415                 f_max = ((speeds[i] * mult) + 50) / 100;
 416                 f_max += (ROUNDING / 2);
 417                 f_min = f_max - ROUNDING;
 418                 if ((speed <= f_max) && (speed >= f_min))
 419                         return speeds[i] / 10;
 420         }
 421         return 0;
 422 }
 423
 424
 425 static int __cpuinit longhaul_get_ranges(void)
 426 {
 427         unsigned int i, j, k = 0;
 428         unsigned int ratio;
 429         int mult;
 430
 431         /* Get current frequency */
 432         mult = longhaul_get_cpu_mult();
 433         if (mult == -1) {
 434                 printk(KERN_INFO PFX "Invalid (reserved) multiplier!\n");
 435                 return -EINVAL;
 436         }
 437         fsb = guess_fsb(mult);
 438         if (fsb == 0) {
 439                 printk(KERN_INFO PFX "Invalid (reserved) FSB!\n");
 440                 return -EINVAL;
 441         }
 442         /* Get max multiplier - as we always did.
 443          * Longhaul MSR is useful only when voltage scaling is enabled.
 444          * C3 is booting at max anyway. */
 445         maxmult = mult;
 446         /* Get min multiplier */
 447         switch (cpu_model) {
 448         case CPU_NEHEMIAH:
 449                 minmult = 50;
 450                 break;
 451         case CPU_NEHEMIAH_C:
 452                 minmult = 40;
 453                 break;
 454         default:
 455                 minmult = 30;
 456                 break;
 457         }
 458
 459         pr_debug("MinMult:%d.%dx MaxMult:%d.%dx\n",
 460                  minmult/10, minmult%10, maxmult/10, maxmult%10);
 461
 462         highest_speed = calc_speed(maxmult);
 463         lowest_speed = calc_speed(minmult);
 464         pr_debug("FSB:%dMHz  Lowest speed: %s   Highest speed:%s\n", fsb,
 465                  print_speed(lowest_speed/1000),
 466                  print_speed(highest_speed/1000));
 467
 468         if (lowest_speed == highest_speed) {
 469                 printk(KERN_INFO PFX "highestspeed == lowest, aborting.\n");
 470                 return -EINVAL;
 471         }
 472         if (lowest_speed > highest_speed) {
 473                 printk(KERN_INFO PFX "nonsense! lowest (%d > %d) !\n",
 474                         lowest_speed, highest_speed);
 475                 return -EINVAL;
 476         }
 477
 478         longhaul_table = kmalloc((numscales + 1) * sizeof(*longhaul_table),
 479                         GFP_KERNEL);
 480         if (!longhaul_table)
 481                 return -ENOMEM;
 482
 483         for (j = 0; j < numscales; j++) {
 484                 ratio = mults[j];
 485                 if (ratio == -1)
 486                         continue;
 487                 if (ratio > maxmult || ratio < minmult)
 488                         continue;
 489                 longhaul_table[k].frequency = calc_speed(ratio);
 490                 longhaul_table[k].index = j;
 491                 k++;
 492         }
 493         if (k <= 1) {
 494                 kfree(longhaul_table);
 495                 return -ENODEV;
 496         }
 497         /* Sort */
 498         for (j = 0; j < k - 1; j++) {
 499                 unsigned int min_f, min_i;
 500                 min_f = longhaul_table[j].frequency;
 501                 min_i = j;
 502                 for (i = j + 1; i < k; i++) {
 503                         if (longhaul_table[i].frequency < min_f) {
 504                                 min_f = longhaul_table[i].frequency;
 505                                 min_i = i;
 506                         }
 507                 }
 508                 if (min_i != j) {
 509                         swap(longhaul_table[j].frequency,
 510                              longhaul_table[min_i].frequency);
 511                         swap(longhaul_table[j].index,
 512                              longhaul_table[min_i].index);
 513                 }
 514         }
 515
 516         longhaul_table[k].frequency = CPUFREQ_TABLE_END;
 517
 518         /* Find index we are running on */
 519         for (j = 0; j < k; j++) {
 520                 if (mults[longhaul_table[j].index & 0x1f] == mult) {
 521                         longhaul_index = j;
 522                         break;
 523                 }
 524         }
 525         return 0;
 526 }
 527
 528
 529 static void __cpuinit longhaul_setup_voltagescaling(void)
 530 {
 531         union msr_longhaul longhaul;
 532         struct mV_pos minvid, maxvid, vid;
 533         unsigned int j, speed, pos, kHz_step, numvscales;
 534         int min_vid_speed;
 535
 536         rdmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 537         if (!(longhaul.bits.RevisionID & 1)) {
 538                 printk(KERN_INFO PFX "Voltage scaling not supported by CPU.\n");
 539                 return;
 540         }
 541
 542         if (!longhaul.bits.VRMRev) {
 543                 printk(KERN_INFO PFX "VRM 8.5\n");
 544                 vrm_mV_table = &vrm85_mV[0];
 545                 mV_vrm_table = &mV_vrm85[0];
 546         } else {
 547                 printk(KERN_INFO PFX "Mobile VRM\n");
 548                 if (cpu_model < CPU_NEHEMIAH)
 549                         return;
 550                 vrm_mV_table = &mobilevrm_mV[0];
 551                 mV_vrm_table = &mV_mobilevrm[0];
 552         }
 553
 554         minvid = vrm_mV_table[longhaul.bits.MinimumVID];
 555         maxvid = vrm_mV_table[longhaul.bits.MaximumVID];
 556
 557         if (minvid.mV == 0 || maxvid.mV == 0 || minvid.mV > maxvid.mV) {
 558                 printk(KERN_INFO PFX "Bogus values Min:%d.%03d Max:%d.%03d. "
 559                                         "Voltage scaling disabled.\n",
 560                                         minvid.mV/1000, minvid.mV%1000,
 561                                         maxvid.mV/1000, maxvid.mV%1000);
 562                 return;
 563         }
 564
 565         if (minvid.mV == maxvid.mV) {
 566                 printk(KERN_INFO PFX "Claims to support voltage scaling but "
 567                                 "min & max are both %d.%03d. "
 568                                 "Voltage scaling disabled\n",
 569                                 maxvid.mV/1000, maxvid.mV%1000);
 570                 return;
 571         }
 572
 573         /* How many voltage steps*/
 574         numvscales = maxvid.pos - minvid.pos + 1;
 575         printk(KERN_INFO PFX
 576                 "Max VID=%d.%03d  "
 577                 "Min VID=%d.%03d, "
 578                 "%d possible voltage scales\n",
 579                 maxvid.mV/1000, maxvid.mV%1000,
 580                 minvid.mV/1000, minvid.mV%1000,
 581                 numvscales);
 582
 583         /* Calculate max frequency at min voltage */
 584         j = longhaul.bits.MinMHzBR;
 585         if (longhaul.bits.MinMHzBR4)
 586                 j += 16;
 587         min_vid_speed = eblcr[j];
 588         if (min_vid_speed == -1)
 589                 return;
 590         switch (longhaul.bits.MinMHzFSB) {
 591         case 0:
 592                 min_vid_speed *= 13333;
 593                 break;
 594         case 1:
 595                 min_vid_speed *= 10000;
 596                 break;
 597         case 3:
 598                 min_vid_speed *= 6666;
 599                 break;
 600         default:
 601                 return;
 602                 break;
 603         }
 604         if (min_vid_speed >= highest_speed)
 605                 return;
 606         /* Calculate kHz for one voltage step */
 607         kHz_step = (highest_speed - min_vid_speed) / numvscales;
 608
 609         j = 0;
 610         while (longhaul_table[j].frequency != CPUFREQ_TABLE_END) {
 611                 speed = longhaul_table[j].frequency;
 612                 if (speed > min_vid_speed)
 613                         pos = (speed - min_vid_speed) / kHz_step + minvid.pos;
 614                 else
 615                         pos = minvid.pos;
 616                 longhaul_table[j].index |= mV_vrm_table[pos] << 8;
 617                 vid = vrm_mV_table[mV_vrm_table[pos]];
 618                 printk(KERN_INFO PFX "f: %d kHz, index: %d, vid: %d mV\n",
 619                                 speed, j, vid.mV);
 620                 j++;
 621         }
 622
 623         can_scale_voltage = 1;
 624         printk(KERN_INFO PFX "Voltage scaling enabled.\n");
 625 }
 626
 627
 628 static int longhaul_verify(struct cpufreq_policy *policy)
 629 {
 630         return cpufreq_frequency_table_verify(policy, longhaul_table);
 631 }
 632
 633
 634 static int longhaul_target(struct cpufreq_policy *policy,
 635                             unsigned int target_freq, unsigned int relation)
 636 {
 637         unsigned int table_index = 0;
 638         unsigned int i;
 639         unsigned int dir = 0;
 640         u8 vid, current_vid;
 641
 642         if (cpufreq_frequency_table_target(policy, longhaul_table, target_freq,
 643                                 relation, &table_index))
 644                 return -EINVAL;
 645
 646         /* Don't set same frequency again */
 647         if (longhaul_index == table_index)
 648                 return 0;
 649
 650         if (!can_scale_voltage)
 651                 longhaul_setstate(table_index);
 652         else {
 653                 /* On test system voltage transitions exceeding single
 654                  * step up or down were turning motherboard off. Both
 655                  * "ondemand" and "userspace" are unsafe. C7 is doing
 656                  * this in hardware, C3 is old and we need to do this
 657                  * in software. */
 658                 i = longhaul_index;
 659                 current_vid = (longhaul_table[longhaul_index].index >> 8);
 660                 current_vid &= 0x1f;
 661                 if (table_index > longhaul_index)
 662                         dir = 1;
 663                 while (i != table_index) {
 664                         vid = (longhaul_table[i].index >> 8) & 0x1f;
 665                         if (vid != current_vid) {
 666                                 longhaul_setstate(i);
 667                                 current_vid = vid;
 668                                 msleep(200);
 669                         }
 670                         if (dir)
 671                                 i++;
 672                         else
 673                                 i--;
 674                 }
 675                 longhaul_setstate(table_index);
 676         }
 677         longhaul_index = table_index;
 678         return 0;
 679 }
 680
 681
 682 static unsigned int longhaul_get(unsigned int cpu)
 683 {
 684         if (cpu)
 685                 return 0;
 686         return calc_speed(longhaul_get_cpu_mult());
 687 }
 688
 689 static acpi_status longhaul_walk_callback(acpi_handle obj_handle,
 690                                           u32 nesting_level,
 691                                           void *context, void **return_value)
 692 {
 693         struct acpi_device *d;
 694
 695         if (acpi_bus_get_device(obj_handle, &d))
 696                 return 0;
 697
 698         *return_value = acpi_driver_data(d);
 699         return 1;
 700 }
 701
 702 /* VIA don't support PM2 reg, but have something similar */
 703 static int enable_arbiter_disable(void)
 704 {
 705         struct pci_dev *dev;
 706         int status = 1;
 707         int reg;
 708         u8 pci_cmd;
 709
 710         /* Find PLE133 host bridge */
 711         reg = 0x78;
 712         dev = pci_get_device(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8601_0,
 713                              NULL);
 714         /* Find PM133/VT8605 host bridge */
 715         if (dev == NULL)
 716                 dev = pci_get_device(PCI_VENDOR_ID_VIA,
 717                                      PCI_DEVICE_ID_VIA_8605_0, NULL);
 718         /* Find CLE266 host bridge */
 719         if (dev == NULL) {
 720                 reg = 0x76;
 721                 dev = pci_get_device(PCI_VENDOR_ID_VIA,
 722                                      PCI_DEVICE_ID_VIA_862X_0, NULL);
 723                 /* Find CN400 V-Link host bridge */
 724                 if (dev == NULL)
 725                         dev = pci_get_device(PCI_VENDOR_ID_VIA, 0x7259, NULL);
 726         }
 727         if (dev != NULL) {
 728                 /* Enable access to port 0x22 */
 729                 pci_read_config_byte(dev, reg, &pci_cmd);
 730                 if (!(pci_cmd & 1<<7)) {
 731                         pci_cmd |= 1<<7;
 732                         pci_write_config_byte(dev, reg, pci_cmd);
 733                         pci_read_config_byte(dev, reg, &pci_cmd);
 734                         if (!(pci_cmd & 1<<7)) {
 735                                 printk(KERN_ERR PFX
 736                                         "Can't enable access to port 0x22.\n");
 737                                 status = 0;
 738                         }
 739                 }
 740                 pci_dev_put(dev);
 741                 return status;
 742         }
 743         return 0;
 744 }
 745
 746 static int longhaul_setup_southbridge(void)
 747 {
 748         struct pci_dev *dev;
 749         u8 pci_cmd;
 750
 751         /* Find VT8235 southbridge */
 752         dev = pci_get_device(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8235, NULL);
 753         if (dev == NULL)
 754                 /* Find VT8237 southbridge */
 755                 dev = pci_get_device(PCI_VENDOR_ID_VIA,
 756                                      PCI_DEVICE_ID_VIA_8237, NULL);
 757         if (dev != NULL) {
 758                 /* Set transition time to max */
 759                 pci_read_config_byte(dev, 0xec, &pci_cmd);
 760                 pci_cmd &= ~(1 << 2);
 761                 pci_write_config_byte(dev, 0xec, pci_cmd);
 762                 pci_read_config_byte(dev, 0xe4, &pci_cmd);
 763                 pci_cmd &= ~(1 << 7);
 764                 pci_write_config_byte(dev, 0xe4, pci_cmd);
 765                 pci_read_config_byte(dev, 0xe5, &pci_cmd);
 766                 pci_cmd |= 1 << 7;
 767                 pci_write_config_byte(dev, 0xe5, pci_cmd);
 768                 /* Get address of ACPI registers block*/
 769                 pci_read_config_byte(dev, 0x81, &pci_cmd);
 770                 if (pci_cmd & 1 << 7) {
 771                         pci_read_config_dword(dev, 0x88, &acpi_regs_addr);
 772                         acpi_regs_addr &= 0xff00;
 773                         printk(KERN_INFO PFX "ACPI I/O at 0x%x\n",
 774                                         acpi_regs_addr);
 775                 }
 776
 777                 pci_dev_put(dev);
 778                 return 1;
 779         }
 780         return 0;
 781 }
 782
 783 static int __cpuinit longhaul_cpu_init(struct cpufreq_policy *policy)
 784 {
 785         struct cpuinfo_x86 *c = &cpu_data(0);
 786         char *cpuname = NULL;
 787         int ret;
 788         u32 lo, hi;
 789
 790         /* Check what we have on this motherboard */
 791         switch (c->x86_model) {
 792         case 6:
 793                 cpu_model = CPU_SAMUEL;
 794                 cpuname = "C3 'Samuel' [C5A]";
 795                 longhaul_version = TYPE_LONGHAUL_V1;
 796                 memcpy(mults, samuel1_mults, sizeof(samuel1_mults));
 797                 memcpy(eblcr, samuel1_eblcr, sizeof(samuel1_eblcr));
 798                 break;
 799
 800         case 7:
 801                 switch (c->x86_mask) {
 802                 case 0:
 803                         longhaul_version = TYPE_LONGHAUL_V1;
 804                         cpu_model = CPU_SAMUEL2;
 805                         cpuname = "C3 'Samuel 2' [C5B]";
 806                         /* Note, this is not a typo, early Samuel2's had
 807                          * Samuel1 ratios. */
 808                         memcpy(mults, samuel1_mults, sizeof(samuel1_mults));
 809                         memcpy(eblcr, samuel2_eblcr, sizeof(samuel2_eblcr));
 810                         break;
 811                 case 1 ... 15:
 812                         longhaul_version = TYPE_LONGHAUL_V2;
 813                         if (c->x86_mask < 8) {
 814                                 cpu_model = CPU_SAMUEL2;
 815                                 cpuname = "C3 'Samuel 2' [C5B]";
 816                         } else {
 817                                 cpu_model = CPU_EZRA;
 818                                 cpuname = "C3 'Ezra' [C5C]";
 819                         }
 820                         memcpy(mults, ezra_mults, sizeof(ezra_mults));
 821                         memcpy(eblcr, ezra_eblcr, sizeof(ezra_eblcr));
 822                         break;
 823                 }
 824                 break;
 825
 826         case 8:
 827                 cpu_model = CPU_EZRA_T;
 828                 cpuname = "C3 'Ezra-T' [C5M]";
 829                 longhaul_version = TYPE_POWERSAVER;
 830                 numscales = 32;
 831                 memcpy(mults, ezrat_mults, sizeof(ezrat_mults));
 832                 memcpy(eblcr, ezrat_eblcr, sizeof(ezrat_eblcr));
 833                 break;
 834
 835         case 9:
 836                 longhaul_version = TYPE_POWERSAVER;
 837                 numscales = 32;
 838                 memcpy(mults, nehemiah_mults, sizeof(nehemiah_mults));
 839                 memcpy(eblcr, nehemiah_eblcr, sizeof(nehemiah_eblcr));
 840                 switch (c->x86_mask) {
 841                 case 0 ... 1:
 842                         cpu_model = CPU_NEHEMIAH;
 843                         cpuname = "C3 'Nehemiah A' [C5XLOE]";
 844                         break;
 845                 case 2 ... 4:
 846                         cpu_model = CPU_NEHEMIAH;
 847                         cpuname = "C3 'Nehemiah B' [C5XLOH]";
 848                         break;
 849                 case 5 ... 15:
 850                         cpu_model = CPU_NEHEMIAH_C;
 851                         cpuname = "C3 'Nehemiah C' [C5P]";
 852                         break;
 853                 }
 854                 break;
 855
 856         default:
 857                 cpuname = "Unknown";
 858                 break;
 859         }
 860         /* Check Longhaul ver. 2 */
 861         if (longhaul_version == TYPE_LONGHAUL_V2) {
 862                 rdmsr(MSR_VIA_LONGHAUL, lo, hi);
 863                 if (lo == 0 && hi == 0)
 864                         /* Looks like MSR isn't present */
 865                         longhaul_version = TYPE_LONGHAUL_V1;
 866         }
 867
 868         printk(KERN_INFO PFX "VIA %s CPU detected.  ", cpuname);
 869         switch (longhaul_version) {
 870         case TYPE_LONGHAUL_V1:
 871         case TYPE_LONGHAUL_V2:
 872                 printk(KERN_CONT "Longhaul v%d supported.\n", longhaul_version);
 873                 break;
 874         case TYPE_POWERSAVER:
 875                 printk(KERN_CONT "Powersaver supported.\n");
 876                 break;
 877         };
 878
 879         /* Doesn't hurt */
 880         longhaul_setup_southbridge();
 881
 882         /* Find ACPI data for processor */
 883         acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
 884                                 ACPI_UINT32_MAX, &longhaul_walk_callback, NULL,
 885                                 NULL, (void *)&pr);
 886
 887         /* Check ACPI support for C3 state */
 888         if (pr != NULL && longhaul_version == TYPE_POWERSAVER) {
 889                 cx = &pr->power.states[ACPI_STATE_C3];
 890                 if (cx->address > 0 && cx->latency <= 1000)
 891                         longhaul_flags |= USE_ACPI_C3;
 892         }
 893         /* Disable if it isn't working */
 894         if (disable_acpi_c3)
 895                 longhaul_flags &= ~USE_ACPI_C3;
 896         /* Check if northbridge is friendly */
 897         if (enable_arbiter_disable())
 898                 longhaul_flags |= USE_NORTHBRIDGE;
 899
 900         /* Check ACPI support for bus master arbiter disable */
 901         if (!(longhaul_flags & USE_ACPI_C3
 902              || longhaul_flags & USE_NORTHBRIDGE)
 903             && ((pr == NULL) || !(pr->flags.bm_control))) {
 904                 printk(KERN_ERR PFX
 905                         "No ACPI support. Unsupported northbridge.\n");
 906                 return -ENODEV;
 907         }
 908
 909         if (longhaul_flags & USE_NORTHBRIDGE)
 910                 printk(KERN_INFO PFX "Using northbridge support.\n");
 911         if (longhaul_flags & USE_ACPI_C3)
 912                 printk(KERN_INFO PFX "Using ACPI support.\n");
 913
 914         ret = longhaul_get_ranges();
 915         if (ret != 0)
 916                 return ret;
 917
 918         if ((longhaul_version != TYPE_LONGHAUL_V1) && (scale_voltage != 0))
 919                 longhaul_setup_voltagescaling();
 920
 921         policy->cpuinfo.transition_latency = 200000;    /* nsec */
 922         policy->cur = calc_speed(longhaul_get_cpu_mult());
 923
 924         ret = cpufreq_frequency_table_cpuinfo(policy, longhaul_table);
 925         if (ret)
 926                 return ret;
 927
 928         cpufreq_frequency_table_get_attr(longhaul_table, policy->cpu);
 929
 930         return 0;
 931 }
 932
 933 static int longhaul_cpu_exit(struct cpufreq_policy *policy)
 934 {
 935         cpufreq_frequency_table_put_attr(policy->cpu);
 936         return 0;
 937 }
 938
 939 static struct freq_attr *longhaul_attr[] = {
 940         &cpufreq_freq_attr_scaling_available_freqs,
 941         NULL,
 942 };
 943
 944 static struct cpufreq_driver longhaul_driver = {
 945         .verify = longhaul_verify,
 946         .target = longhaul_target,
 947         .get    = longhaul_get,
 948         .init   = longhaul_cpu_init,
 949         .exit   = longhaul_cpu_exit,
 950         .name   = "longhaul",
 951         .owner  = THIS_MODULE,
 952         .attr   = longhaul_attr,
 953 };
 954
 955 static const struct x86_cpu_id longhaul_id[] = {
 956         { X86_VENDOR_CENTAUR, 6 },
 957         {}
 958 };
 959 MODULE_DEVICE_TABLE(x86cpu, longhaul_id);
 960
 961 static int __init longhaul_init(void)
 962 {
 963         struct cpuinfo_x86 *c = &cpu_data(0);
 964
 965         if (!x86_match_cpu(longhaul_id))
 966                 return -ENODEV;
 967
 968         if (!enable) {
 969                 printk(KERN_ERR PFX "Option \"enable\" not set. Aborting.\n");
 970                 return -ENODEV;
 971         }
 972 #ifdef CONFIG_SMP
 973         if (num_online_cpus() > 1) {
 974                 printk(KERN_ERR PFX "More than 1 CPU detected, "
 975                                 "longhaul disabled.\n");
 976                 return -ENODEV;
 977         }
 978 #endif
 979 #ifdef CONFIG_X86_IO_APIC
 980         if (cpu_has_apic) {
 981                 printk(KERN_ERR PFX "APIC detected. Longhaul is currently "
 982                                 "broken in this configuration.\n");
 983                 return -ENODEV;
 984         }
 985 #endif
 986         switch (c->x86_model) {
 987         case 6 ... 9:
 988                 return cpufreq_register_driver(&longhaul_driver);
 989         case 10:
 990                 printk(KERN_ERR PFX "Use acpi-cpufreq driver for VIA C7\n");
 991         default:
 992                 ;
 993         }
 994
 995         return -ENODEV;
 996 }
 997
 998
 999 static void __exit longhaul_exit(void)
1000 {
1001         int i;
1002
1003         for (i = 0; i < numscales; i++) {
1004                 if (mults[i] == maxmult) {
1005                         longhaul_setstate(i);
1006                         break;
1007                 }
1008         }
1009
1010         cpufreq_unregister_driver(&longhaul_driver);
1011         kfree(longhaul_table);
1012 }
1013
1014 /* Even if BIOS is exporting ACPI C3 state, and it is used
1015  * with success when CPU is idle, this state doesn't
1016  * trigger frequency transition in some cases. */
1017 module_param(disable_acpi_c3, int, 0644);
1018 MODULE_PARM_DESC(disable_acpi_c3, "Don't use ACPI C3 support");
1019 /* Change CPU voltage with frequency. Very useful to save
1020  * power, but most VIA C3 processors aren't supporting it. */
1021 module_param(scale_voltage, int, 0644);
1022 MODULE_PARM_DESC(scale_voltage, "Scale voltage of processor");
1023 /* Force revision key to 0 for processors which doesn't
1024  * support voltage scaling, but are introducing itself as
1025  * such. */
1026 module_param(revid_errata, int, 0644);
1027 MODULE_PARM_DESC(revid_errata, "Ignore CPU Revision ID");
1028 /* By default driver is disabled to prevent incompatible
1029  * system freeze. */
1030 module_param(enable, int, 0644);
1031 MODULE_PARM_DESC(enable, "Enable driver");
1032
1033 MODULE_AUTHOR("Dave Jones <davej@redhat.com>");
1034 MODULE_DESCRIPTION("Longhaul driver for VIA Cyrix processors.");
1035 MODULE_LICENSE("GPL");
1036
1037 late_initcall(longhaul_init);
1038 module_exit(longhaul_exit);