arch/x86/kernel/cpu/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 <acpi/processor.h>
  39
  40 #include "longhaul.h"
  41
  42 #define PFX "longhaul: "
  43
  44 #define TYPE_LONGHAUL_V1        1
  45 #define TYPE_LONGHAUL_V2        2
  46 #define TYPE_POWERSAVER         3
  47
  48 #define CPU_SAMUEL      1
  49 #define CPU_SAMUEL2     2
  50 #define CPU_EZRA        3
  51 #define CPU_EZRA_T      4
  52 #define CPU_NEHEMIAH    5
  53 #define CPU_NEHEMIAH_C  6
  54
  55 /* Flags */
  56 #define USE_ACPI_C3             (1 << 1)
  57 #define USE_NORTHBRIDGE         (1 << 2)
  58
  59 static int cpu_model;
  60 static unsigned int numscales = 16;
  61 static unsigned int fsb;
  62
  63 static const struct mV_pos *vrm_mV_table;
  64 static const unsigned char *mV_vrm_table;
  65
  66 static unsigned int highest_speed, lowest_speed; /* kHz */
  67 static unsigned int minmult, maxmult;
  68 static int can_scale_voltage;
  69 static struct acpi_processor *pr;
  70 static struct acpi_processor_cx *cx;
  71 static u32 acpi_regs_addr;
  72 static u8 longhaul_flags;
  73 static unsigned int longhaul_index;
  74
  75 /* Module parameters */
  76 static int scale_voltage;
  77 static int disable_acpi_c3;
  78 static int revid_errata;
  79
  80 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, \
  81                 "longhaul", msg)
  82
  83
  84 /* Clock ratios multiplied by 10 */
  85 static int mults[32];
  86 static int eblcr[32];
  87 static int longhaul_version;
  88 static struct cpufreq_frequency_table *longhaul_table;
  89
  90 #ifdef CONFIG_CPU_FREQ_DEBUG
  91 static char speedbuffer[8];
  92
  93 static char *print_speed(int speed)
  94 {
  95         if (speed < 1000) {
  96                 snprintf(speedbuffer, sizeof(speedbuffer), "%dMHz", speed);
  97                 return speedbuffer;
  98         }
  99
 100         if (speed%1000 == 0)
 101                 snprintf(speedbuffer, sizeof(speedbuffer),
 102                         "%dGHz", speed/1000);
 103         else
 104                 snprintf(speedbuffer, sizeof(speedbuffer),
 105                         "%d.%dGHz", speed/1000, (speed%1000)/100);
 106
 107         return speedbuffer;
 108 }
 109 #endif
 110
 111
 112 static unsigned int calc_speed(int mult)
 113 {
 114         int khz;
 115         khz = (mult/10)*fsb;
 116         if (mult%10)
 117                 khz += fsb/2;
 118         khz *= 1000;
 119         return khz;
 120 }
 121
 122
 123 static int longhaul_get_cpu_mult(void)
 124 {
 125         unsigned long invalue = 0, lo, hi;
 126
 127         rdmsr(MSR_IA32_EBL_CR_POWERON, lo, hi);
 128         invalue = (lo & (1<<22|1<<23|1<<24|1<<25))>>22;
 129         if (longhaul_version == TYPE_LONGHAUL_V2 ||
 130             longhaul_version == TYPE_POWERSAVER) {
 131                 if (lo & (1<<27))
 132                         invalue += 16;
 133         }
 134         return eblcr[invalue];
 135 }
 136
 137 /* For processor with BCR2 MSR */
 138
 139 static void do_longhaul1(unsigned int mults_index)
 140 {
 141         union msr_bcr2 bcr2;
 142
 143         rdmsrl(MSR_VIA_BCR2, bcr2.val);
 144         /* Enable software clock multiplier */
 145         bcr2.bits.ESOFTBF = 1;
 146         bcr2.bits.CLOCKMUL = mults_index & 0xff;
 147
 148         /* Sync to timer tick */
 149         safe_halt();
 150         /* Change frequency on next halt or sleep */
 151         wrmsrl(MSR_VIA_BCR2, bcr2.val);
 152         /* Invoke transition */
 153         ACPI_FLUSH_CPU_CACHE();
 154         halt();
 155
 156         /* Disable software clock multiplier */
 157         local_irq_disable();
 158         rdmsrl(MSR_VIA_BCR2, bcr2.val);
 159         bcr2.bits.ESOFTBF = 0;
 160         wrmsrl(MSR_VIA_BCR2, bcr2.val);
 161 }
 162
 163 /* For processor with Longhaul MSR */
 164
 165 static void do_powersaver(int cx_address, unsigned int mults_index,
 166                           unsigned int dir)
 167 {
 168         union msr_longhaul longhaul;
 169         u32 t;
 170
 171         rdmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 172         /* Setup new frequency */
 173         if (!revid_errata)
 174                 longhaul.bits.RevisionKey = longhaul.bits.RevisionID;
 175         else
 176                 longhaul.bits.RevisionKey = 0;
 177         longhaul.bits.SoftBusRatio = mults_index & 0xf;
 178         longhaul.bits.SoftBusRatio4 = (mults_index & 0x10) >> 4;
 179         /* Setup new voltage */
 180         if (can_scale_voltage)
 181                 longhaul.bits.SoftVID = (mults_index >> 8) & 0x1f;
 182         /* Sync to timer tick */
 183         safe_halt();
 184         /* Raise voltage if necessary */
 185         if (can_scale_voltage && dir) {
 186                 longhaul.bits.EnableSoftVID = 1;
 187                 wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 188                 /* Change voltage */
 189                 if (!cx_address) {
 190                         ACPI_FLUSH_CPU_CACHE();
 191                         halt();
 192                 } else {
 193                         ACPI_FLUSH_CPU_CACHE();
 194                         /* Invoke C3 */
 195                         inb(cx_address);
 196                         /* Dummy op - must do something useless after P_LVL3
 197                          * read */
 198                         t = inl(acpi_gbl_FADT.xpm_timer_block.address);
 199                 }
 200                 longhaul.bits.EnableSoftVID = 0;
 201                 wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 202         }
 203
 204         /* Change frequency on next halt or sleep */
 205         longhaul.bits.EnableSoftBusRatio = 1;
 206         wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 207         if (!cx_address) {
 208                 ACPI_FLUSH_CPU_CACHE();
 209                 halt();
 210         } else {
 211                 ACPI_FLUSH_CPU_CACHE();
 212                 /* Invoke C3 */
 213                 inb(cx_address);
 214                 /* Dummy op - must do something useless after P_LVL3 read */
 215                 t = inl(acpi_gbl_FADT.xpm_timer_block.address);
 216         }
 217         /* Disable bus ratio bit */
 218         longhaul.bits.EnableSoftBusRatio = 0;
 219         wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 220
 221         /* Reduce voltage if necessary */
 222         if (can_scale_voltage && !dir) {
 223                 longhaul.bits.EnableSoftVID = 1;
 224                 wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 225                 /* Change voltage */
 226                 if (!cx_address) {
 227                         ACPI_FLUSH_CPU_CACHE();
 228                         halt();
 229                 } else {
 230                         ACPI_FLUSH_CPU_CACHE();
 231                         /* Invoke C3 */
 232                         inb(cx_address);
 233                         /* Dummy op - must do something useless after P_LVL3
 234                          * read */
 235                         t = inl(acpi_gbl_FADT.xpm_timer_block.address);
 236                 }
 237                 longhaul.bits.EnableSoftVID = 0;
 238                 wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 239         }
 240 }
 241
 242 /**
 243  * longhaul_set_cpu_frequency()
 244  * @mults_index : bitpattern of the new multiplier.
 245  *
 246  * Sets a new clock ratio.
 247  */
 248
 249 static void longhaul_setstate(unsigned int table_index)
 250 {
 251         unsigned int mults_index;
 252         int speed, mult;
 253         struct cpufreq_freqs freqs;
 254         unsigned long flags;
 255         unsigned int pic1_mask, pic2_mask;
 256         u16 bm_status = 0;
 257         u32 bm_timeout = 1000;
 258         unsigned int dir = 0;
 259
 260         mults_index = longhaul_table[table_index].index;
 261         /* Safety precautions */
 262         mult = mults[mults_index & 0x1f];
 263         if (mult == -1)
 264                 return;
 265         speed = calc_speed(mult);
 266         if ((speed > highest_speed) || (speed < lowest_speed))
 267                 return;
 268         /* Voltage transition before frequency transition? */
 269         if (can_scale_voltage && longhaul_index < table_index)
 270                 dir = 1;
 271
 272         freqs.old = calc_speed(longhaul_get_cpu_mult());
 273         freqs.new = speed;
 274         freqs.cpu = 0; /* longhaul.c is UP only driver */
 275
 276         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 277
 278         dprintk("Setting to FSB:%dMHz Mult:%d.%dx (%s)\n",
 279                         fsb, mult/10, mult%10, print_speed(speed/1000));
 280 retry_loop:
 281         preempt_disable();
 282         local_irq_save(flags);
 283
 284         pic2_mask = inb(0xA1);
 285         pic1_mask = inb(0x21);  /* works on C3. save mask. */
 286         outb(0xFF, 0xA1);       /* Overkill */
 287         outb(0xFE, 0x21);       /* TMR0 only */
 288
 289         /* Wait while PCI bus is busy. */
 290         if (acpi_regs_addr && (longhaul_flags & USE_NORTHBRIDGE
 291             || ((pr != NULL) && pr->flags.bm_control))) {
 292                 bm_status = inw(acpi_regs_addr);
 293                 bm_status &= 1 << 4;
 294                 while (bm_status && bm_timeout) {
 295                         outw(1 << 4, acpi_regs_addr);
 296                         bm_timeout--;
 297                         bm_status = inw(acpi_regs_addr);
 298                         bm_status &= 1 << 4;
 299                 }
 300         }
 301
 302         if (longhaul_flags & USE_NORTHBRIDGE) {
 303                 /* Disable AGP and PCI arbiters */
 304                 outb(3, 0x22);
 305         } else if ((pr != NULL) && pr->flags.bm_control) {
 306                 /* Disable bus master arbitration */
 307                 acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 1);
 308         }
 309         switch (longhaul_version) {
 310
 311         /*
 312          * Longhaul v1. (Samuel[C5A] and Samuel2 stepping 0[C5B])
 313          * Software controlled multipliers only.
 314          */
 315         case TYPE_LONGHAUL_V1:
 316                 do_longhaul1(mults_index);
 317                 break;
 318
 319         /*
 320          * Longhaul v2 appears in Samuel2 Steppings 1->7 [C5B] and Ezra [C5C]
 321          *
 322          * Longhaul v3 (aka Powersaver). (Ezra-T [C5M] & Nehemiah [C5N])
 323          * Nehemiah can do FSB scaling too, but this has never been proven
 324          * to work in practice.
 325          */
 326         case TYPE_LONGHAUL_V2:
 327         case TYPE_POWERSAVER:
 328                 if (longhaul_flags & USE_ACPI_C3) {
 329                         /* Don't allow wakeup */
 330                         acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
 331                         do_powersaver(cx->address, mults_index, dir);
 332                 } else {
 333                         do_powersaver(0, mults_index, dir);
 334                 }
 335                 break;
 336         }
 337
 338         if (longhaul_flags & USE_NORTHBRIDGE) {
 339                 /* Enable arbiters */
 340                 outb(0, 0x22);
 341         } else if ((pr != NULL) && pr->flags.bm_control) {
 342                 /* Enable bus master arbitration */
 343                 acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 0);
 344         }
 345         outb(pic2_mask, 0xA1);  /* restore mask */
 346         outb(pic1_mask, 0x21);
 347
 348         local_irq_restore(flags);
 349         preempt_enable();
 350
 351         freqs.new = calc_speed(longhaul_get_cpu_mult());
 352         /* Check if requested frequency is set. */
 353         if (unlikely(freqs.new != speed)) {
 354                 printk(KERN_INFO PFX "Failed to set requested frequency!\n");
 355                 /* Revision ID = 1 but processor is expecting revision key
 356                  * equal to 0. Jumpers at the bottom of processor will change
 357                  * multiplier and FSB, but will not change bits in Longhaul
 358                  * MSR nor enable voltage scaling. */
 359                 if (!revid_errata) {
 360                         printk(KERN_INFO PFX "Enabling \"Ignore Revision ID\" "
 361                                                 "option.\n");
 362                         revid_errata = 1;
 363                         msleep(200);
 364                         goto retry_loop;
 365                 }
 366                 /* Why ACPI C3 sometimes doesn't work is a mystery for me.
 367                  * But it does happen. Processor is entering ACPI C3 state,
 368                  * but it doesn't change frequency. I tried poking various
 369                  * bits in northbridge registers, but without success. */
 370                 if (longhaul_flags & USE_ACPI_C3) {
 371                         printk(KERN_INFO PFX "Disabling ACPI C3 support.\n");
 372                         longhaul_flags &= ~USE_ACPI_C3;
 373                         if (revid_errata) {
 374                                 printk(KERN_INFO PFX "Disabling \"Ignore "
 375                                                 "Revision ID\" option.\n");
 376                                 revid_errata = 0;
 377                         }
 378                         msleep(200);
 379                         goto retry_loop;
 380                 }
 381                 /* This shouldn't happen. Longhaul ver. 2 was reported not
 382                  * working on processors without voltage scaling, but with
 383                  * RevID = 1. RevID errata will make things right. Just
 384                  * to be 100% sure. */
 385                 if (longhaul_version == TYPE_LONGHAUL_V2) {
 386                         printk(KERN_INFO PFX "Switching to Longhaul ver. 1\n");
 387                         longhaul_version = TYPE_LONGHAUL_V1;
 388                         msleep(200);
 389                         goto retry_loop;
 390                 }
 391         }
 392         /* Report true CPU frequency */
 393         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 394
 395         if (!bm_timeout)
 396                 printk(KERN_INFO PFX "Warning: Timeout while waiting for "
 397                                 "idle PCI bus.\n");
 398 }
 399
 400 /*
 401  * Centaur decided to make life a little more tricky.
 402  * Only longhaul v1 is allowed to read EBLCR BSEL[0:1].
 403  * Samuel2 and above have to try and guess what the FSB is.
 404  * We do this by assuming we booted at maximum multiplier, and interpolate
 405  * between that value multiplied by possible FSBs and cpu_mhz which
 406  * was calculated at boot time. Really ugly, but no other way to do this.
 407  */
 408
 409 #define ROUNDING        0xf
 410
 411 static int guess_fsb(int mult)
 412 {
 413         int speed = cpu_khz / 1000;
 414         int i;
 415         int speeds[] = { 666, 1000, 1333, 2000 };
 416         int f_max, f_min;
 417
 418         for (i = 0; i < 4; i++) {
 419                 f_max = ((speeds[i] * mult) + 50) / 100;
 420                 f_max += (ROUNDING / 2);
 421                 f_min = f_max - ROUNDING;
 422                 if ((speed <= f_max) && (speed >= f_min))
 423                         return speeds[i] / 10;
 424         }
 425         return 0;
 426 }
 427
 428
 429 static int __init longhaul_get_ranges(void)
 430 {
 431         unsigned int i, j, k = 0;
 432         unsigned int ratio;
 433         int mult;
 434
 435         /* Get current frequency */
 436         mult = longhaul_get_cpu_mult();
 437         if (mult == -1) {
 438                 printk(KERN_INFO PFX "Invalid (reserved) multiplier!\n");
 439                 return -EINVAL;
 440         }
 441         fsb = guess_fsb(mult);
 442         if (fsb == 0) {
 443                 printk(KERN_INFO PFX "Invalid (reserved) FSB!\n");
 444                 return -EINVAL;
 445         }
 446         /* Get max multiplier - as we always did.
 447          * Longhaul MSR is usefull only when voltage scaling is enabled.
 448          * C3 is booting at max anyway. */
 449         maxmult = mult;
 450         /* Get min multiplier */
 451         switch (cpu_model) {
 452         case CPU_NEHEMIAH:
 453                 minmult = 50;
 454                 break;
 455         case CPU_NEHEMIAH_C:
 456                 minmult = 40;
 457                 break;
 458         default:
 459                 minmult = 30;
 460                 break;
 461         }
 462
 463         dprintk("MinMult:%d.%dx MaxMult:%d.%dx\n",
 464                  minmult/10, minmult%10, maxmult/10, maxmult%10);
 465
 466         highest_speed = calc_speed(maxmult);
 467         lowest_speed = calc_speed(minmult);
 468         dprintk("FSB:%dMHz  Lowest speed: %s   Highest speed:%s\n", fsb,
 469                  print_speed(lowest_speed/1000),
 470                  print_speed(highest_speed/1000));
 471
 472         if (lowest_speed == highest_speed) {
 473                 printk(KERN_INFO PFX "highestspeed == lowest, aborting.\n");
 474                 return -EINVAL;
 475         }
 476         if (lowest_speed > highest_speed) {
 477                 printk(KERN_INFO PFX "nonsense! lowest (%d > %d) !\n",
 478                         lowest_speed, highest_speed);
 479                 return -EINVAL;
 480         }
 481
 482         longhaul_table = kmalloc((numscales + 1) * sizeof(*longhaul_table),
 483                         GFP_KERNEL);
 484         if (!longhaul_table)
 485                 return -ENOMEM;
 486
 487         for (j = 0; j < numscales; j++) {
 488                 ratio = mults[j];
 489                 if (ratio == -1)
 490                         continue;
 491                 if (ratio > maxmult || ratio < minmult)
 492                         continue;
 493                 longhaul_table[k].frequency = calc_speed(ratio);
 494                 longhaul_table[k].index = j;
 495                 k++;
 496         }
 497         if (k <= 1) {
 498                 kfree(longhaul_table);
 499                 return -ENODEV;
 500         }
 501         /* Sort */
 502         for (j = 0; j < k - 1; j++) {
 503                 unsigned int min_f, min_i;
 504                 min_f = longhaul_table[j].frequency;
 505                 min_i = j;
 506                 for (i = j + 1; i < k; i++) {
 507                         if (longhaul_table[i].frequency < min_f) {
 508                                 min_f = longhaul_table[i].frequency;
 509                                 min_i = i;
 510                         }
 511                 }
 512                 if (min_i != j) {
 513                         swap(longhaul_table[j].frequency,
 514                              longhaul_table[min_i].frequency);
 515                         swap(longhaul_table[j].index,
 516                              longhaul_table[min_i].index);
 517                 }
 518         }
 519
 520         longhaul_table[k].frequency = CPUFREQ_TABLE_END;
 521
 522         /* Find index we are running on */
 523         for (j = 0; j < k; j++) {
 524                 if (mults[longhaul_table[j].index & 0x1f] == mult) {
 525                         longhaul_index = j;
 526                         break;
 527                 }
 528         }
 529         return 0;
 530 }
 531
 532
 533 static void __init longhaul_setup_voltagescaling(void)
 534 {
 535         union msr_longhaul longhaul;
 536         struct mV_pos minvid, maxvid, vid;
 537         unsigned int j, speed, pos, kHz_step, numvscales;
 538         int min_vid_speed;
 539
 540         rdmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 541         if (!(longhaul.bits.RevisionID & 1)) {
 542                 printk(KERN_INFO PFX "Voltage scaling not supported by CPU.\n");
 543                 return;
 544         }
 545
 546         if (!longhaul.bits.VRMRev) {
 547                 printk(KERN_INFO PFX "VRM 8.5\n");
 548                 vrm_mV_table = &vrm85_mV[0];
 549                 mV_vrm_table = &mV_vrm85[0];
 550         } else {
 551                 printk(KERN_INFO PFX "Mobile VRM\n");
 552                 if (cpu_model < CPU_NEHEMIAH)
 553                         return;
 554                 vrm_mV_table = &mobilevrm_mV[0];
 555                 mV_vrm_table = &mV_mobilevrm[0];
 556         }
 557
 558         minvid = vrm_mV_table[longhaul.bits.MinimumVID];
 559         maxvid = vrm_mV_table[longhaul.bits.MaximumVID];
 560
 561         if (minvid.mV == 0 || maxvid.mV == 0 || minvid.mV > maxvid.mV) {
 562                 printk(KERN_INFO PFX "Bogus values Min:%d.%03d Max:%d.%03d. "
 563                                         "Voltage scaling disabled.\n",
 564                                         minvid.mV/1000, minvid.mV%1000,
 565                                         maxvid.mV/1000, maxvid.mV%1000);
 566                 return;
 567         }
 568
 569         if (minvid.mV == maxvid.mV) {
 570                 printk(KERN_INFO PFX "Claims to support voltage scaling but "
 571                                 "min & max are both %d.%03d. "
 572                                 "Voltage scaling disabled\n",
 573                                 maxvid.mV/1000, maxvid.mV%1000);
 574                 return;
 575         }
 576
 577         /* How many voltage steps*/
 578         numvscales = maxvid.pos - minvid.pos + 1;
 579         printk(KERN_INFO PFX
 580                 "Max VID=%d.%03d  "
 581                 "Min VID=%d.%03d, "
 582                 "%d possible voltage scales\n",
 583                 maxvid.mV/1000, maxvid.mV%1000,
 584                 minvid.mV/1000, minvid.mV%1000,
 585                 numvscales);
 586
 587         /* Calculate max frequency at min voltage */
 588         j = longhaul.bits.MinMHzBR;
 589         if (longhaul.bits.MinMHzBR4)
 590                 j += 16;
 591         min_vid_speed = eblcr[j];
 592         if (min_vid_speed == -1)
 593                 return;
 594         switch (longhaul.bits.MinMHzFSB) {
 595         case 0:
 596                 min_vid_speed *= 13333;
 597                 break;
 598         case 1:
 599                 min_vid_speed *= 10000;
 600                 break;
 601         case 3:
 602                 min_vid_speed *= 6666;
 603                 break;
 604         default:
 605                 return;
 606                 break;
 607         }
 608         if (min_vid_speed >= highest_speed)
 609                 return;
 610         /* Calculate kHz for one voltage step */
 611         kHz_step = (highest_speed - min_vid_speed) / numvscales;
 612
 613         j = 0;
 614         while (longhaul_table[j].frequency != CPUFREQ_TABLE_END) {
 615                 speed = longhaul_table[j].frequency;
 616                 if (speed > min_vid_speed)
 617                         pos = (speed - min_vid_speed) / kHz_step + minvid.pos;
 618                 else
 619                         pos = minvid.pos;
 620                 longhaul_table[j].index |= mV_vrm_table[pos] << 8;
 621                 vid = vrm_mV_table[mV_vrm_table[pos]];
 622                 printk(KERN_INFO PFX "f: %d kHz, index: %d, vid: %d mV\n",
 623                                 speed, j, vid.mV);
 624                 j++;
 625         }
 626
 627         can_scale_voltage = 1;
 628         printk(KERN_INFO PFX "Voltage scaling enabled.\n");
 629 }
 630
 631
 632 static int longhaul_verify(struct cpufreq_policy *policy)
 633 {
 634         return cpufreq_frequency_table_verify(policy, longhaul_table);
 635 }
 636
 637
 638 static int longhaul_target(struct cpufreq_policy *policy,
 639                             unsigned int target_freq, unsigned int relation)
 640 {
 641         unsigned int table_index = 0;
 642         unsigned int i;
 643         unsigned int dir = 0;
 644         u8 vid, current_vid;
 645
 646         if (cpufreq_frequency_table_target(policy, longhaul_table, target_freq,
 647                                 relation, &table_index))
 648                 return -EINVAL;
 649
 650         /* Don't set same frequency again */
 651         if (longhaul_index == table_index)
 652                 return 0;
 653
 654         if (!can_scale_voltage)
 655                 longhaul_setstate(table_index);
 656         else {
 657                 /* On test system voltage transitions exceeding single
 658                  * step up or down were turning motherboard off. Both
 659                  * "ondemand" and "userspace" are unsafe. C7 is doing
 660                  * this in hardware, C3 is old and we need to do this
 661                  * in software. */
 662                 i = longhaul_index;
 663                 current_vid = (longhaul_table[longhaul_index].index >> 8);
 664                 current_vid &= 0x1f;
 665                 if (table_index > longhaul_index)
 666                         dir = 1;
 667                 while (i != table_index) {
 668                         vid = (longhaul_table[i].index >> 8) & 0x1f;
 669                         if (vid != current_vid) {
 670                                 longhaul_setstate(i);
 671                                 current_vid = vid;
 672                                 msleep(200);
 673                         }
 674                         if (dir)
 675                                 i++;
 676                         else
 677                                 i--;
 678                 }
 679                 longhaul_setstate(table_index);
 680         }
 681         longhaul_index = table_index;
 682         return 0;
 683 }
 684
 685
 686 static unsigned int longhaul_get(unsigned int cpu)
 687 {
 688         if (cpu)
 689                 return 0;
 690         return calc_speed(longhaul_get_cpu_mult());
 691 }
 692
 693 static acpi_status longhaul_walk_callback(acpi_handle obj_handle,
 694                                           u32 nesting_level,
 695                                           void *context, void **return_value)
 696 {
 697         struct acpi_device *d;
 698
 699         if (acpi_bus_get_device(obj_handle, &d))
 700                 return 0;
 701
 702         *return_value = acpi_driver_data(d);
 703         return 1;
 704 }
 705
 706 /* VIA don't support PM2 reg, but have something similar */
 707 static int enable_arbiter_disable(void)
 708 {
 709         struct pci_dev *dev;
 710         int status = 1;
 711         int reg;
 712         u8 pci_cmd;
 713
 714         /* Find PLE133 host bridge */
 715         reg = 0x78;
 716         dev = pci_get_device(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8601_0,
 717                              NULL);
 718         /* Find PM133/VT8605 host bridge */
 719         if (dev == NULL)
 720                 dev = pci_get_device(PCI_VENDOR_ID_VIA,
 721                                      PCI_DEVICE_ID_VIA_8605_0, NULL);
 722         /* Find CLE266 host bridge */
 723         if (dev == NULL) {
 724                 reg = 0x76;
 725                 dev = pci_get_device(PCI_VENDOR_ID_VIA,
 726                                      PCI_DEVICE_ID_VIA_862X_0, NULL);
 727                 /* Find CN400 V-Link host bridge */
 728                 if (dev == NULL)
 729                         dev = pci_get_device(PCI_VENDOR_ID_VIA, 0x7259, NULL);
 730         }
 731         if (dev != NULL) {
 732                 /* Enable access to port 0x22 */
 733                 pci_read_config_byte(dev, reg, &pci_cmd);
 734                 if (!(pci_cmd & 1<<7)) {
 735                         pci_cmd |= 1<<7;
 736                         pci_write_config_byte(dev, reg, pci_cmd);
 737                         pci_read_config_byte(dev, reg, &pci_cmd);
 738                         if (!(pci_cmd & 1<<7)) {
 739                                 printk(KERN_ERR PFX
 740                                         "Can't enable access to port 0x22.\n");
 741                                 status = 0;
 742                         }
 743                 }
 744                 pci_dev_put(dev);
 745                 return status;
 746         }
 747         return 0;
 748 }
 749
 750 static int longhaul_setup_southbridge(void)
 751 {
 752         struct pci_dev *dev;
 753         u8 pci_cmd;
 754
 755         /* Find VT8235 southbridge */
 756         dev = pci_get_device(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8235, NULL);
 757         if (dev == NULL)
 758                 /* Find VT8237 southbridge */
 759                 dev = pci_get_device(PCI_VENDOR_ID_VIA,
 760                                      PCI_DEVICE_ID_VIA_8237, NULL);
 761         if (dev != NULL) {
 762                 /* Set transition time to max */
 763                 pci_read_config_byte(dev, 0xec, &pci_cmd);
 764                 pci_cmd &= ~(1 << 2);
 765                 pci_write_config_byte(dev, 0xec, pci_cmd);
 766                 pci_read_config_byte(dev, 0xe4, &pci_cmd);
 767                 pci_cmd &= ~(1 << 7);
 768                 pci_write_config_byte(dev, 0xe4, pci_cmd);
 769                 pci_read_config_byte(dev, 0xe5, &pci_cmd);
 770                 pci_cmd |= 1 << 7;
 771                 pci_write_config_byte(dev, 0xe5, pci_cmd);
 772                 /* Get address of ACPI registers block*/
 773                 pci_read_config_byte(dev, 0x81, &pci_cmd);
 774                 if (pci_cmd & 1 << 7) {
 775                         pci_read_config_dword(dev, 0x88, &acpi_regs_addr);
 776                         acpi_regs_addr &= 0xff00;
 777                         printk(KERN_INFO PFX "ACPI I/O at 0x%x\n",
 778                                         acpi_regs_addr);
 779                 }
 780
 781                 pci_dev_put(dev);
 782                 return 1;
 783         }
 784         return 0;
 785 }
 786
 787 static int __init longhaul_cpu_init(struct cpufreq_policy *policy)
 788 {
 789         struct cpuinfo_x86 *c = &cpu_data(0);
 790         char *cpuname = NULL;
 791         int ret;
 792         u32 lo, hi;
 793
 794         /* Check what we have on this motherboard */
 795         switch (c->x86_model) {
 796         case 6:
 797                 cpu_model = CPU_SAMUEL;
 798                 cpuname = "C3 'Samuel' [C5A]";
 799                 longhaul_version = TYPE_LONGHAUL_V1;
 800                 memcpy(mults, samuel1_mults, sizeof(samuel1_mults));
 801                 memcpy(eblcr, samuel1_eblcr, sizeof(samuel1_eblcr));
 802                 break;
 803
 804         case 7:
 805                 switch (c->x86_mask) {
 806                 case 0:
 807                         longhaul_version = TYPE_LONGHAUL_V1;
 808                         cpu_model = CPU_SAMUEL2;
 809                         cpuname = "C3 'Samuel 2' [C5B]";
 810                         /* Note, this is not a typo, early Samuel2's had
 811                          * Samuel1 ratios. */
 812                         memcpy(mults, samuel1_mults, sizeof(samuel1_mults));
 813                         memcpy(eblcr, samuel2_eblcr, sizeof(samuel2_eblcr));
 814                         break;
 815                 case 1 ... 15:
 816                         longhaul_version = TYPE_LONGHAUL_V2;
 817                         if (c->x86_mask < 8) {
 818                                 cpu_model = CPU_SAMUEL2;
 819                                 cpuname = "C3 'Samuel 2' [C5B]";
 820                         } else {
 821                                 cpu_model = CPU_EZRA;
 822                                 cpuname = "C3 'Ezra' [C5C]";
 823                         }
 824                         memcpy(mults, ezra_mults, sizeof(ezra_mults));
 825                         memcpy(eblcr, ezra_eblcr, sizeof(ezra_eblcr));
 826                         break;
 827                 }
 828                 break;
 829
 830         case 8:
 831                 cpu_model = CPU_EZRA_T;
 832                 cpuname = "C3 'Ezra-T' [C5M]";
 833                 longhaul_version = TYPE_POWERSAVER;
 834                 numscales = 32;
 835                 memcpy(mults, ezrat_mults, sizeof(ezrat_mults));
 836                 memcpy(eblcr, ezrat_eblcr, sizeof(ezrat_eblcr));
 837                 break;
 838
 839         case 9:
 840                 longhaul_version = TYPE_POWERSAVER;
 841                 numscales = 32;
 842                 memcpy(mults, nehemiah_mults, sizeof(nehemiah_mults));
 843                 memcpy(eblcr, nehemiah_eblcr, sizeof(nehemiah_eblcr));
 844                 switch (c->x86_mask) {
 845                 case 0 ... 1:
 846                         cpu_model = CPU_NEHEMIAH;
 847                         cpuname = "C3 'Nehemiah A' [C5XLOE]";
 848                         break;
 849                 case 2 ... 4:
 850                         cpu_model = CPU_NEHEMIAH;
 851                         cpuname = "C3 'Nehemiah B' [C5XLOH]";
 852                         break;
 853                 case 5 ... 15:
 854                         cpu_model = CPU_NEHEMIAH_C;
 855                         cpuname = "C3 'Nehemiah C' [C5P]";
 856                         break;
 857                 }
 858                 break;
 859
 860         default:
 861                 cpuname = "Unknown";
 862                 break;
 863         }
 864         /* Check Longhaul ver. 2 */
 865         if (longhaul_version == TYPE_LONGHAUL_V2) {
 866                 rdmsr(MSR_VIA_LONGHAUL, lo, hi);
 867                 if (lo == 0 && hi == 0)
 868                         /* Looks like MSR isn't present */
 869                         longhaul_version = TYPE_LONGHAUL_V1;
 870         }
 871
 872         printk(KERN_INFO PFX "VIA %s CPU detected.  ", cpuname);
 873         switch (longhaul_version) {
 874         case TYPE_LONGHAUL_V1:
 875         case TYPE_LONGHAUL_V2:
 876                 printk(KERN_CONT "Longhaul v%d supported.\n", longhaul_version);
 877                 break;
 878         case TYPE_POWERSAVER:
 879                 printk(KERN_CONT "Powersaver supported.\n");
 880                 break;
 881         };
 882
 883         /* Doesn't hurt */
 884         longhaul_setup_southbridge();
 885
 886         /* Find ACPI data for processor */
 887         acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
 888                                 ACPI_UINT32_MAX, &longhaul_walk_callback, NULL,
 889                                 NULL, (void *)&pr);
 890
 891         /* Check ACPI support for C3 state */
 892         if (pr != NULL && longhaul_version == TYPE_POWERSAVER) {
 893                 cx = &pr->power.states[ACPI_STATE_C3];
 894                 if (cx->address > 0 && cx->latency <= 1000)
 895                         longhaul_flags |= USE_ACPI_C3;
 896         }
 897         /* Disable if it isn't working */
 898         if (disable_acpi_c3)
 899                 longhaul_flags &= ~USE_ACPI_C3;
 900         /* Check if northbridge is friendly */
 901         if (enable_arbiter_disable())
 902                 longhaul_flags |= USE_NORTHBRIDGE;
 903
 904         /* Check ACPI support for bus master arbiter disable */
 905         if (!(longhaul_flags & USE_ACPI_C3
 906              || longhaul_flags & USE_NORTHBRIDGE)
 907             && ((pr == NULL) || !(pr->flags.bm_control))) {
 908                 printk(KERN_ERR PFX
 909                         "No ACPI support. Unsupported northbridge.\n");
 910                 return -ENODEV;
 911         }
 912
 913         if (longhaul_flags & USE_NORTHBRIDGE)
 914                 printk(KERN_INFO PFX "Using northbridge support.\n");
 915         if (longhaul_flags & USE_ACPI_C3)
 916                 printk(KERN_INFO PFX "Using ACPI support.\n");
 917
 918         ret = longhaul_get_ranges();
 919         if (ret != 0)
 920                 return ret;
 921
 922         if ((longhaul_version != TYPE_LONGHAUL_V1) && (scale_voltage != 0))
 923                 longhaul_setup_voltagescaling();
 924
 925         policy->cpuinfo.transition_latency = 200000;    /* nsec */
 926         policy->cur = calc_speed(longhaul_get_cpu_mult());
 927
 928         ret = cpufreq_frequency_table_cpuinfo(policy, longhaul_table);
 929         if (ret)
 930                 return ret;
 931
 932         cpufreq_frequency_table_get_attr(longhaul_table, policy->cpu);
 933
 934         return 0;
 935 }
 936
 937 static int __devexit longhaul_cpu_exit(struct cpufreq_policy *policy)
 938 {
 939         cpufreq_frequency_table_put_attr(policy->cpu);
 940         return 0;
 941 }
 942
 943 static struct freq_attr *longhaul_attr[] = {
 944         &cpufreq_freq_attr_scaling_available_freqs,
 945         NULL,
 946 };
 947
 948 static struct cpufreq_driver longhaul_driver = {
 949         .verify = longhaul_verify,
 950         .target = longhaul_target,
 951         .get    = longhaul_get,
 952         .init   = longhaul_cpu_init,
 953         .exit   = __devexit_p(longhaul_cpu_exit),
 954         .name   = "longhaul",
 955         .owner  = THIS_MODULE,
 956         .attr   = longhaul_attr,
 957 };
 958
 959
 960 static int __init longhaul_init(void)
 961 {
 962         struct cpuinfo_x86 *c = &cpu_data(0);
 963
 964         if (c->x86_vendor != X86_VENDOR_CENTAUR || c->x86 != 6)
 965                 return -ENODEV;
 966
 967 #ifdef CONFIG_SMP
 968         if (num_online_cpus() > 1) {
 969                 printk(KERN_ERR PFX "More than 1 CPU detected, "
 970                                 "longhaul disabled.\n");
 971                 return -ENODEV;
 972         }
 973 #endif
 974 #ifdef CONFIG_X86_IO_APIC
 975         if (cpu_has_apic) {
 976                 printk(KERN_ERR PFX "APIC detected. Longhaul is currently "
 977                                 "broken in this configuration.\n");
 978                 return -ENODEV;
 979         }
 980 #endif
 981         switch (c->x86_model) {
 982         case 6 ... 9:
 983                 return cpufreq_register_driver(&longhaul_driver);
 984         case 10:
 985                 printk(KERN_ERR PFX "Use acpi-cpufreq driver for VIA C7\n");
 986         default:
 987                 ;
 988         }
 989
 990         return -ENODEV;
 991 }
 992
 993
 994 static void __exit longhaul_exit(void)
 995 {
 996         int i;
 997
 998         for (i = 0; i < numscales; i++) {
 999                 if (mults[i] == maxmult) {
1000                         longhaul_setstate(i);
1001                         break;
1002                 }
1003         }
1004
1005         cpufreq_unregister_driver(&longhaul_driver);
1006         kfree(longhaul_table);
1007 }
1008
1009 /* Even if BIOS is exporting ACPI C3 state, and it is used
1010  * with success when CPU is idle, this state doesn't
1011  * trigger frequency transition in some cases. */
1012 module_param(disable_acpi_c3, int, 0644);
1013 MODULE_PARM_DESC(disable_acpi_c3, "Don't use ACPI C3 support");
1014 /* Change CPU voltage with frequency. Very usefull to save
1015  * power, but most VIA C3 processors aren't supporting it. */
1016 module_param(scale_voltage, int, 0644);
1017 MODULE_PARM_DESC(scale_voltage, "Scale voltage of processor");
1018 /* Force revision key to 0 for processors which doesn't
1019  * support voltage scaling, but are introducing itself as
1020  * such. */
1021 module_param(revid_errata, int, 0644);
1022 MODULE_PARM_DESC(revid_errata, "Ignore CPU Revision ID");
1023
1024 MODULE_AUTHOR("Dave Jones <davej@redhat.com>");
1025 MODULE_DESCRIPTION("Longhaul driver for VIA Cyrix processors.");
1026 MODULE_LICENSE("GPL");
1027
1028 late_initcall(longhaul_init);
1029 module_exit(longhaul_exit);