arch/i386/kernel/cpu/cpufreq/longhaul.c

   1 /*
   2  *  (C) 2001-2004  Dave Jones. <davej@codemonkey.org.uk>
   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
  33 #include <asm/msr.h>
  34 #include <asm/timex.h>
  35 #include <asm/io.h>
  36 #include <asm/acpi.h>
  37 #include <linux/acpi.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 #define USE_VT8235              (1 << 3)
  59
  60 static int cpu_model;
  61 static unsigned int numscales=16;
  62 static unsigned int fsb;
  63
  64 static struct mV_pos *vrm_mV_table;
  65 static unsigned char *mV_vrm_table;
  66 struct f_msr {
  67         u8 vrm;
  68         u8 pos;
  69 };
  70 static struct f_msr f_msr_table[32];
  71
  72 static unsigned int highest_speed, lowest_speed; /* kHz */
  73 static unsigned int minmult, maxmult;
  74 static int can_scale_voltage;
  75 static struct acpi_processor *pr = NULL;
  76 static struct acpi_processor_cx *cx = NULL;
  77 static u8 longhaul_flags;
  78 static u8 longhaul_pos;
  79
  80 /* Module parameters */
  81 static int scale_voltage;
  82
  83 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "longhaul", msg)
  84
  85
  86 /* Clock ratios multiplied by 10 */
  87 static int clock_ratio[32];
  88 static int eblcr_table[32];
  89 static int longhaul_version;
  90 static struct cpufreq_frequency_table *longhaul_table;
  91
  92 #ifdef CONFIG_CPU_FREQ_DEBUG
  93 static char speedbuffer[8];
  94
  95 static char *print_speed(int speed)
  96 {
  97         if (speed < 1000) {
  98                 snprintf(speedbuffer, sizeof(speedbuffer),"%dMHz", speed);
  99                 return speedbuffer;
 100         }
 101
 102         if (speed%1000 == 0)
 103                 snprintf(speedbuffer, sizeof(speedbuffer),
 104                         "%dGHz", speed/1000);
 105         else
 106                 snprintf(speedbuffer, sizeof(speedbuffer),
 107                         "%d.%dGHz", speed/1000, (speed%1000)/100);
 108
 109         return speedbuffer;
 110 }
 111 #endif
 112
 113
 114 static unsigned int calc_speed(int mult)
 115 {
 116         int khz;
 117         khz = (mult/10)*fsb;
 118         if (mult%10)
 119                 khz += fsb/2;
 120         khz *= 1000;
 121         return khz;
 122 }
 123
 124
 125 static int longhaul_get_cpu_mult(void)
 126 {
 127         unsigned long invalue=0,lo, hi;
 128
 129         rdmsr (MSR_IA32_EBL_CR_POWERON, lo, hi);
 130         invalue = (lo & (1<<22|1<<23|1<<24|1<<25)) >>22;
 131         if (longhaul_version==TYPE_LONGHAUL_V2 || longhaul_version==TYPE_POWERSAVER) {
 132                 if (lo & (1<<27))
 133                         invalue+=16;
 134         }
 135         return eblcr_table[invalue];
 136 }
 137
 138 /* For processor with BCR2 MSR */
 139
 140 static void do_longhaul1(unsigned int clock_ratio_index)
 141 {
 142         union msr_bcr2 bcr2;
 143
 144         rdmsrl(MSR_VIA_BCR2, bcr2.val);
 145         /* Enable software clock multiplier */
 146         bcr2.bits.ESOFTBF = 1;
 147         bcr2.bits.CLOCKMUL = clock_ratio_index;
 148
 149         /* Sync to timer tick */
 150         safe_halt();
 151         /* Change frequency on next halt or sleep */
 152         wrmsrl(MSR_VIA_BCR2, bcr2.val);
 153         /* Invoke transition */
 154         ACPI_FLUSH_CPU_CACHE();
 155         halt();
 156
 157         /* Disable software clock multiplier */
 158         local_irq_disable();
 159         rdmsrl(MSR_VIA_BCR2, bcr2.val);
 160         bcr2.bits.ESOFTBF = 0;
 161         wrmsrl(MSR_VIA_BCR2, bcr2.val);
 162 }
 163
 164 /* For processor with Longhaul MSR */
 165
 166 static void do_powersaver(int cx_address, unsigned int clock_ratio_index)
 167 {
 168         union msr_longhaul longhaul;
 169         u8 dest_pos;
 170         u32 t;
 171
 172         dest_pos = f_msr_table[clock_ratio_index].pos;
 173
 174         rdmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 175         /* Setup new frequency */
 176         longhaul.bits.RevisionKey = longhaul.bits.RevisionID;
 177         longhaul.bits.SoftBusRatio = clock_ratio_index & 0xf;
 178         longhaul.bits.SoftBusRatio4 = (clock_ratio_index & 0x10) >> 4;
 179         /* Setup new voltage */
 180         if (can_scale_voltage)
 181                 longhaul.bits.SoftVID = f_msr_table[clock_ratio_index].vrm;
 182         /* Sync to timer tick */
 183         safe_halt();
 184         /* Raise voltage if necessary */
 185         if (can_scale_voltage && longhaul_pos < dest_pos) {
 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                 longhaul_pos = dest_pos;
 203         }
 204
 205         /* Change frequency on next halt or sleep */
 206         longhaul.bits.EnableSoftBusRatio = 1;
 207         wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 208         if (!cx_address) {
 209                 ACPI_FLUSH_CPU_CACHE();
 210                 halt();
 211         } else {
 212                 ACPI_FLUSH_CPU_CACHE();
 213                 /* Invoke C3 */
 214                 inb(cx_address);
 215                 /* Dummy op - must do something useless after P_LVL3 read */
 216                 t = inl(acpi_gbl_FADT.xpm_timer_block.address);
 217         }
 218         /* Disable bus ratio bit */
 219         longhaul.bits.EnableSoftBusRatio = 0;
 220         wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 221
 222         /* Reduce voltage if necessary */
 223         if (can_scale_voltage && longhaul_pos > dest_pos) {
 224                 longhaul.bits.EnableSoftVID = 1;
 225                 wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 226                 /* Change voltage */
 227                 if (!cx_address) {
 228                         ACPI_FLUSH_CPU_CACHE();
 229                         halt();
 230                 } else {
 231                         ACPI_FLUSH_CPU_CACHE();
 232                         /* Invoke C3 */
 233                         inb(cx_address);
 234                         /* Dummy op - must do something useless after P_LVL3
 235                          * read */
 236                         t = inl(acpi_gbl_FADT.xpm_timer_block.address);
 237                 }
 238                 longhaul.bits.EnableSoftVID = 0;
 239                 wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 240                 longhaul_pos = dest_pos;
 241         }
 242 }
 243
 244 /**
 245  * longhaul_set_cpu_frequency()
 246  * @clock_ratio_index : bitpattern of the new multiplier.
 247  *
 248  * Sets a new clock ratio.
 249  */
 250
 251 static void longhaul_setstate(unsigned int clock_ratio_index)
 252 {
 253         int speed, mult;
 254         struct cpufreq_freqs freqs;
 255         static unsigned int old_ratio=-1;
 256         unsigned long flags;
 257         unsigned int pic1_mask, pic2_mask;
 258
 259         if (old_ratio == clock_ratio_index)
 260                 return;
 261         old_ratio = clock_ratio_index;
 262
 263         mult = clock_ratio[clock_ratio_index];
 264         if (mult == -1)
 265                 return;
 266
 267         speed = calc_speed(mult);
 268         if ((speed > highest_speed) || (speed < lowest_speed))
 269                 return;
 270
 271         freqs.old = calc_speed(longhaul_get_cpu_mult());
 272         freqs.new = speed;
 273         freqs.cpu = 0; /* longhaul.c is UP only driver */
 274
 275         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 276
 277         dprintk ("Setting to FSB:%dMHz Mult:%d.%dx (%s)\n",
 278                         fsb, mult/10, mult%10, print_speed(speed/1000));
 279
 280         preempt_disable();
 281         local_irq_save(flags);
 282
 283         pic2_mask = inb(0xA1);
 284         pic1_mask = inb(0x21);  /* works on C3. save mask. */
 285         outb(0xFF,0xA1);        /* Overkill */
 286         outb(0xFE,0x21);        /* TMR0 only */
 287
 288         if (longhaul_flags & USE_NORTHBRIDGE) {
 289                 /* Disable AGP and PCI arbiters */
 290                 outb(3, 0x22);
 291         } else if ((pr != NULL) && pr->flags.bm_control) {
 292                 /* Disable bus master arbitration */
 293                 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1);
 294         }
 295         switch (longhaul_version) {
 296
 297         /*
 298          * Longhaul v1. (Samuel[C5A] and Samuel2 stepping 0[C5B])
 299          * Software controlled multipliers only.
 300          */
 301         case TYPE_LONGHAUL_V1:
 302                 do_longhaul1(clock_ratio_index);
 303                 break;
 304
 305         /*
 306          * Longhaul v2 appears in Samuel2 Steppings 1->7 [C5B] and Ezra [C5C]
 307          *
 308          * Longhaul v3 (aka Powersaver). (Ezra-T [C5M] & Nehemiah [C5N])
 309          * Nehemiah can do FSB scaling too, but this has never been proven
 310          * to work in practice.
 311          */
 312         case TYPE_LONGHAUL_V2:
 313         case TYPE_POWERSAVER:
 314                 if (longhaul_flags & USE_ACPI_C3) {
 315                         /* Don't allow wakeup */
 316                         acpi_set_register(ACPI_BITREG_BUS_MASTER_RLD, 0);
 317                         do_powersaver(cx->address, clock_ratio_index);
 318                 } else {
 319                         do_powersaver(0, clock_ratio_index);
 320                 }
 321                 break;
 322         }
 323
 324         if (longhaul_flags & USE_NORTHBRIDGE) {
 325                 /* Enable arbiters */
 326                 outb(0, 0x22);
 327         } else if ((pr != NULL) && pr->flags.bm_control) {
 328                 /* Enable bus master arbitration */
 329                 acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
 330         }
 331         outb(pic2_mask,0xA1);   /* restore mask */
 332         outb(pic1_mask,0x21);
 333
 334         local_irq_restore(flags);
 335         preempt_enable();
 336
 337         freqs.new = calc_speed(longhaul_get_cpu_mult());
 338         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 339 }
 340
 341 /*
 342  * Centaur decided to make life a little more tricky.
 343  * Only longhaul v1 is allowed to read EBLCR BSEL[0:1].
 344  * Samuel2 and above have to try and guess what the FSB is.
 345  * We do this by assuming we booted at maximum multiplier, and interpolate
 346  * between that value multiplied by possible FSBs and cpu_mhz which
 347  * was calculated at boot time. Really ugly, but no other way to do this.
 348  */
 349
 350 #define ROUNDING        0xf
 351
 352 static int guess_fsb(int mult)
 353 {
 354         int speed = cpu_khz / 1000;
 355         int i;
 356         int speeds[] = { 666, 1000, 1333, 2000 };
 357         int f_max, f_min;
 358
 359         for (i = 0; i < 4; i++) {
 360                 f_max = ((speeds[i] * mult) + 50) / 100;
 361                 f_max += (ROUNDING / 2);
 362                 f_min = f_max - ROUNDING;
 363                 if ((speed <= f_max) && (speed >= f_min))
 364                         return speeds[i] / 10;
 365         }
 366         return 0;
 367 }
 368
 369
 370 static int __init longhaul_get_ranges(void)
 371 {
 372         unsigned int j, k = 0;
 373         int mult;
 374
 375         /* Get current frequency */
 376         mult = longhaul_get_cpu_mult();
 377         if (mult == -1) {
 378                 printk(KERN_INFO PFX "Invalid (reserved) multiplier!\n");
 379                 return -EINVAL;
 380         }
 381         fsb = guess_fsb(mult);
 382         if (fsb == 0) {
 383                 printk(KERN_INFO PFX "Invalid (reserved) FSB!\n");
 384                 return -EINVAL;
 385         }
 386         /* Get max multiplier - as we always did.
 387          * Longhaul MSR is usefull only when voltage scaling is enabled.
 388          * C3 is booting at max anyway. */
 389         maxmult = mult;
 390         /* Get min multiplier */
 391         switch (cpu_model) {
 392         case CPU_NEHEMIAH:
 393                 minmult = 50;
 394                 break;
 395         case CPU_NEHEMIAH_C:
 396                 minmult = 40;
 397                 break;
 398         default:
 399                 minmult = 30;
 400                 break;
 401         }
 402
 403         dprintk ("MinMult:%d.%dx MaxMult:%d.%dx\n",
 404                  minmult/10, minmult%10, maxmult/10, maxmult%10);
 405
 406         highest_speed = calc_speed(maxmult);
 407         lowest_speed = calc_speed(minmult);
 408         dprintk ("FSB:%dMHz  Lowest speed: %s   Highest speed:%s\n", fsb,
 409                  print_speed(lowest_speed/1000),
 410                  print_speed(highest_speed/1000));
 411
 412         if (lowest_speed == highest_speed) {
 413                 printk (KERN_INFO PFX "highestspeed == lowest, aborting.\n");
 414                 return -EINVAL;
 415         }
 416         if (lowest_speed > highest_speed) {
 417                 printk (KERN_INFO PFX "nonsense! lowest (%d > %d) !\n",
 418                         lowest_speed, highest_speed);
 419                 return -EINVAL;
 420         }
 421
 422         longhaul_table = kmalloc((numscales + 1) * sizeof(struct cpufreq_frequency_table), GFP_KERNEL);
 423         if(!longhaul_table)
 424                 return -ENOMEM;
 425
 426         for (j=0; j < numscales; j++) {
 427                 unsigned int ratio;
 428                 ratio = clock_ratio[j];
 429                 if (ratio == -1)
 430                         continue;
 431                 if (ratio > maxmult || ratio < minmult)
 432                         continue;
 433                 longhaul_table[k].frequency = calc_speed(ratio);
 434                 longhaul_table[k].index = j;
 435                 k++;
 436         }
 437
 438         longhaul_table[k].frequency = CPUFREQ_TABLE_END;
 439         if (!k) {
 440                 kfree (longhaul_table);
 441                 return -EINVAL;
 442         }
 443
 444         return 0;
 445 }
 446
 447
 448 static void __init longhaul_setup_voltagescaling(void)
 449 {
 450         union msr_longhaul longhaul;
 451         struct mV_pos minvid, maxvid;
 452         unsigned int j, speed, pos, kHz_step, numvscales;
 453         int min_vid_speed;
 454
 455         rdmsrl(MSR_VIA_LONGHAUL, longhaul.val);
 456         if (!(longhaul.bits.RevisionID & 1)) {
 457                 printk(KERN_INFO PFX "Voltage scaling not supported by CPU.\n");
 458                 return;
 459         }
 460
 461         if (!longhaul.bits.VRMRev) {
 462                 printk (KERN_INFO PFX "VRM 8.5\n");
 463                 vrm_mV_table = &vrm85_mV[0];
 464                 mV_vrm_table = &mV_vrm85[0];
 465         } else {
 466                 printk (KERN_INFO PFX "Mobile VRM\n");
 467                 if (cpu_model < CPU_NEHEMIAH)
 468                         return;
 469                 vrm_mV_table = &mobilevrm_mV[0];
 470                 mV_vrm_table = &mV_mobilevrm[0];
 471         }
 472
 473         minvid = vrm_mV_table[longhaul.bits.MinimumVID];
 474         maxvid = vrm_mV_table[longhaul.bits.MaximumVID];
 475
 476         if (minvid.mV == 0 || maxvid.mV == 0 || minvid.mV > maxvid.mV) {
 477                 printk (KERN_INFO PFX "Bogus values Min:%d.%03d Max:%d.%03d. "
 478                                         "Voltage scaling disabled.\n",
 479                                         minvid.mV/1000, minvid.mV%1000, maxvid.mV/1000, maxvid.mV%1000);
 480                 return;
 481         }
 482
 483         if (minvid.mV == maxvid.mV) {
 484                 printk (KERN_INFO PFX "Claims to support voltage scaling but min & max are "
 485                                 "both %d.%03d. Voltage scaling disabled\n",
 486                                 maxvid.mV/1000, maxvid.mV%1000);
 487                 return;
 488         }
 489
 490         /* How many voltage steps */
 491         numvscales = maxvid.pos - minvid.pos + 1;
 492         printk(KERN_INFO PFX
 493                 "Max VID=%d.%03d  "
 494                 "Min VID=%d.%03d, "
 495                 "%d possible voltage scales\n",
 496                 maxvid.mV/1000, maxvid.mV%1000,
 497                 minvid.mV/1000, minvid.mV%1000,
 498                 numvscales);
 499
 500         /* Calculate max frequency at min voltage */
 501         j = longhaul.bits.MinMHzBR;
 502         if (longhaul.bits.MinMHzBR4)
 503                 j += 16;
 504         min_vid_speed = eblcr_table[j];
 505         if (min_vid_speed == -1)
 506                 return;
 507         switch (longhaul.bits.MinMHzFSB) {
 508         case 0:
 509                 min_vid_speed *= 13333;
 510                 break;
 511         case 1:
 512                 min_vid_speed *= 10000;
 513                 break;
 514         case 3:
 515                 min_vid_speed *= 6666;
 516                 break;
 517         default:
 518                 return;
 519                 break;
 520         }
 521         if (min_vid_speed >= highest_speed)
 522                 return;
 523         /* Calculate kHz for one voltage step */
 524         kHz_step = (highest_speed - min_vid_speed) / numvscales;
 525
 526
 527         j = 0;
 528         while (longhaul_table[j].frequency != CPUFREQ_TABLE_END) {
 529                 speed = longhaul_table[j].frequency;
 530                 if (speed > min_vid_speed)
 531                         pos = (speed - min_vid_speed) / kHz_step + minvid.pos;
 532                 else
 533                         pos = minvid.pos;
 534                 f_msr_table[longhaul_table[j].index].vrm = mV_vrm_table[pos];
 535                 f_msr_table[longhaul_table[j].index].pos = pos;
 536                 j++;
 537         }
 538
 539         longhaul_pos = maxvid.pos;
 540         can_scale_voltage = 1;
 541         printk(KERN_INFO PFX "Voltage scaling enabled. "
 542                 "Use of \"conservative\" governor is highly recommended.\n");
 543 }
 544
 545
 546 static int longhaul_verify(struct cpufreq_policy *policy)
 547 {
 548         return cpufreq_frequency_table_verify(policy, longhaul_table);
 549 }
 550
 551
 552 static int longhaul_target(struct cpufreq_policy *policy,
 553                             unsigned int target_freq, unsigned int relation)
 554 {
 555         unsigned int table_index = 0;
 556         unsigned int new_clock_ratio = 0;
 557
 558         if (cpufreq_frequency_table_target(policy, longhaul_table, target_freq, relation, &table_index))
 559                 return -EINVAL;
 560
 561         new_clock_ratio = longhaul_table[table_index].index & 0xFF;
 562
 563         longhaul_setstate(new_clock_ratio);
 564
 565         return 0;
 566 }
 567
 568
 569 static unsigned int longhaul_get(unsigned int cpu)
 570 {
 571         if (cpu)
 572                 return 0;
 573         return calc_speed(longhaul_get_cpu_mult());
 574 }
 575
 576 static acpi_status longhaul_walk_callback(acpi_handle obj_handle,
 577                                           u32 nesting_level,
 578                                           void *context, void **return_value)
 579 {
 580         struct acpi_device *d;
 581
 582         if ( acpi_bus_get_device(obj_handle, &d) ) {
 583                 return 0;
 584         }
 585         *return_value = (void *)acpi_driver_data(d);
 586         return 1;
 587 }
 588
 589 /* VIA don't support PM2 reg, but have something similar */
 590 static int enable_arbiter_disable(void)
 591 {
 592         struct pci_dev *dev;
 593         int reg;
 594         u8 pci_cmd;
 595
 596         /* Find PLE133 host bridge */
 597         reg = 0x78;
 598         dev = pci_find_device(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8601_0, NULL);
 599         /* Find CLE266 host bridge */
 600         if (dev == NULL) {
 601                 reg = 0x76;
 602                 dev = pci_find_device(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_862X_0, NULL);
 603                 /* Find CN400 V-Link host bridge */
 604                 if (dev == NULL)
 605                         dev = pci_find_device(PCI_VENDOR_ID_VIA, 0x7259, NULL);
 606
 607         }
 608         if (dev != NULL) {
 609                 /* Enable access to port 0x22 */
 610                 pci_read_config_byte(dev, reg, &pci_cmd);
 611                 if (!(pci_cmd & 1<<7)) {
 612                         pci_cmd |= 1<<7;
 613                         pci_write_config_byte(dev, reg, pci_cmd);
 614                         pci_read_config_byte(dev, reg, &pci_cmd);
 615                         if (!(pci_cmd & 1<<7)) {
 616                                 printk(KERN_ERR PFX
 617                                         "Can't enable access to port 0x22.\n");
 618                                 return 0;
 619                         }
 620                 }
 621                 return 1;
 622         }
 623         return 0;
 624 }
 625
 626 static int longhaul_setup_vt8235(void)
 627 {
 628         struct pci_dev *dev;
 629         u8 pci_cmd;
 630
 631         /* Find VT8235 southbridge */
 632         dev = pci_find_device(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8235, NULL);
 633         if (dev != NULL) {
 634                 /* Set transition time to max */
 635                 pci_read_config_byte(dev, 0xec, &pci_cmd);
 636                 pci_cmd &= ~(1 << 2);
 637                 pci_write_config_byte(dev, 0xec, pci_cmd);
 638                 pci_read_config_byte(dev, 0xe4, &pci_cmd);
 639                 pci_cmd &= ~(1 << 7);
 640                 pci_write_config_byte(dev, 0xe4, pci_cmd);
 641                 pci_read_config_byte(dev, 0xe5, &pci_cmd);
 642                 pci_cmd |= 1 << 7;
 643                 pci_write_config_byte(dev, 0xe5, pci_cmd);
 644                 return 1;
 645         }
 646         return 0;
 647 }
 648
 649 static int __init longhaul_cpu_init(struct cpufreq_policy *policy)
 650 {
 651         struct cpuinfo_x86 *c = cpu_data;
 652         char *cpuname=NULL;
 653         int ret;
 654         u32 lo, hi;
 655         int vt8235_present;
 656
 657         /* Check what we have on this motherboard */
 658         switch (c->x86_model) {
 659         case 6:
 660                 cpu_model = CPU_SAMUEL;
 661                 cpuname = "C3 'Samuel' [C5A]";
 662                 longhaul_version = TYPE_LONGHAUL_V1;
 663                 memcpy (clock_ratio, samuel1_clock_ratio, sizeof(samuel1_clock_ratio));
 664                 memcpy (eblcr_table, samuel1_eblcr, sizeof(samuel1_eblcr));
 665                 break;
 666
 667         case 7:
 668                 switch (c->x86_mask) {
 669                 case 0:
 670                         longhaul_version = TYPE_LONGHAUL_V1;
 671                         cpu_model = CPU_SAMUEL2;
 672                         cpuname = "C3 'Samuel 2' [C5B]";
 673                         /* Note, this is not a typo, early Samuel2's had
 674                          * Samuel1 ratios. */
 675                         memcpy(clock_ratio, samuel1_clock_ratio,
 676                                 sizeof(samuel1_clock_ratio));
 677                         memcpy(eblcr_table, samuel2_eblcr,
 678                                 sizeof(samuel2_eblcr));
 679                         break;
 680                 case 1 ... 15:
 681                         longhaul_version = TYPE_LONGHAUL_V2;
 682                         if (c->x86_mask < 8) {
 683                                 cpu_model = CPU_SAMUEL2;
 684                                 cpuname = "C3 'Samuel 2' [C5B]";
 685                         } else {
 686                                 cpu_model = CPU_EZRA;
 687                                 cpuname = "C3 'Ezra' [C5C]";
 688                         }
 689                         memcpy(clock_ratio, ezra_clock_ratio,
 690                                 sizeof(ezra_clock_ratio));
 691                         memcpy(eblcr_table, ezra_eblcr,
 692                                 sizeof(ezra_eblcr));
 693                         break;
 694                 }
 695                 break;
 696
 697         case 8:
 698                 cpu_model = CPU_EZRA_T;
 699                 cpuname = "C3 'Ezra-T' [C5M]";
 700                 longhaul_version = TYPE_POWERSAVER;
 701                 numscales=32;
 702                 memcpy (clock_ratio, ezrat_clock_ratio, sizeof(ezrat_clock_ratio));
 703                 memcpy (eblcr_table, ezrat_eblcr, sizeof(ezrat_eblcr));
 704                 break;
 705
 706         case 9:
 707                 longhaul_version = TYPE_POWERSAVER;
 708                 numscales = 32;
 709                 memcpy(clock_ratio,
 710                        nehemiah_clock_ratio,
 711                        sizeof(nehemiah_clock_ratio));
 712                 memcpy(eblcr_table, nehemiah_eblcr, sizeof(nehemiah_eblcr));
 713                 switch (c->x86_mask) {
 714                 case 0 ... 1:
 715                         cpu_model = CPU_NEHEMIAH;
 716                         cpuname = "C3 'Nehemiah A' [C5XLOE]";
 717                         break;
 718                 case 2 ... 4:
 719                         cpu_model = CPU_NEHEMIAH;
 720                         cpuname = "C3 'Nehemiah B' [C5XLOH]";
 721                         break;
 722                 case 5 ... 15:
 723                         cpu_model = CPU_NEHEMIAH_C;
 724                         cpuname = "C3 'Nehemiah C' [C5P]";
 725                         break;
 726                 }
 727                 break;
 728
 729         default:
 730                 cpuname = "Unknown";
 731                 break;
 732         }
 733         /* Check Longhaul ver. 2 */
 734         if (longhaul_version == TYPE_LONGHAUL_V2) {
 735                 rdmsr(MSR_VIA_LONGHAUL, lo, hi);
 736                 if (lo == 0 && hi == 0)
 737                         /* Looks like MSR isn't present */
 738                         longhaul_version = TYPE_LONGHAUL_V1;
 739         }
 740
 741         printk (KERN_INFO PFX "VIA %s CPU detected.  ", cpuname);
 742         switch (longhaul_version) {
 743         case TYPE_LONGHAUL_V1:
 744         case TYPE_LONGHAUL_V2:
 745                 printk ("Longhaul v%d supported.\n", longhaul_version);
 746                 break;
 747         case TYPE_POWERSAVER:
 748                 printk ("Powersaver supported.\n");
 749                 break;
 750         };
 751
 752         /* Doesn't hurt */
 753         vt8235_present = longhaul_setup_vt8235();
 754
 755         /* Find ACPI data for processor */
 756         acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
 757                                 ACPI_UINT32_MAX, &longhaul_walk_callback,
 758                                 NULL, (void *)&pr);
 759
 760         /* Check ACPI support for C3 state */
 761         if (pr != NULL && longhaul_version != TYPE_LONGHAUL_V1) {
 762                 cx = &pr->power.states[ACPI_STATE_C3];
 763                 if (cx->address > 0 && cx->latency <= 1000) {
 764                         longhaul_flags |= USE_ACPI_C3;
 765                         goto print_support_type;
 766                 }
 767         }
 768         /* Check if northbridge is friendly */
 769         if (enable_arbiter_disable()) {
 770                 longhaul_flags |= USE_NORTHBRIDGE;
 771                 goto print_support_type;
 772         }
 773         /* Use VT8235 southbridge if present */
 774         if (longhaul_version == TYPE_POWERSAVER && vt8235_present) {
 775                 longhaul_flags |= USE_VT8235;
 776                 goto print_support_type;
 777         }
 778         /* Check ACPI support for bus master arbiter disable */
 779         if ((pr == NULL) || !(pr->flags.bm_control)) {
 780                 printk(KERN_ERR PFX
 781                         "No ACPI support. Unsupported northbridge.\n");
 782                 return -ENODEV;
 783         }
 784
 785 print_support_type:
 786         if (longhaul_flags & USE_NORTHBRIDGE)
 787                 printk (KERN_INFO PFX "Using northbridge support.\n");
 788         else if (longhaul_flags & USE_VT8235)
 789                 printk (KERN_INFO PFX "Using VT8235 support.\n");
 790         else
 791                 printk (KERN_INFO PFX "Using ACPI support.\n");
 792
 793         ret = longhaul_get_ranges();
 794         if (ret != 0)
 795                 return ret;
 796
 797         if ((longhaul_version != TYPE_LONGHAUL_V1) && (scale_voltage != 0))
 798                 longhaul_setup_voltagescaling();
 799
 800         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 801         policy->cpuinfo.transition_latency = 200000;    /* nsec */
 802         policy->cur = calc_speed(longhaul_get_cpu_mult());
 803
 804         ret = cpufreq_frequency_table_cpuinfo(policy, longhaul_table);
 805         if (ret)
 806                 return ret;
 807
 808         cpufreq_frequency_table_get_attr(longhaul_table, policy->cpu);
 809
 810         return 0;
 811 }
 812
 813 static int __devexit longhaul_cpu_exit(struct cpufreq_policy *policy)
 814 {
 815         cpufreq_frequency_table_put_attr(policy->cpu);
 816         return 0;
 817 }
 818
 819 static struct freq_attr* longhaul_attr[] = {
 820         &cpufreq_freq_attr_scaling_available_freqs,
 821         NULL,
 822 };
 823
 824 static struct cpufreq_driver longhaul_driver = {
 825         .verify = longhaul_verify,
 826         .target = longhaul_target,
 827         .get    = longhaul_get,
 828         .init   = longhaul_cpu_init,
 829         .exit   = __devexit_p(longhaul_cpu_exit),
 830         .name   = "longhaul",
 831         .owner  = THIS_MODULE,
 832         .attr   = longhaul_attr,
 833 };
 834
 835
 836 static int __init longhaul_init(void)
 837 {
 838         struct cpuinfo_x86 *c = cpu_data;
 839
 840         if (c->x86_vendor != X86_VENDOR_CENTAUR || c->x86 != 6)
 841                 return -ENODEV;
 842
 843 #ifdef CONFIG_SMP
 844         if (num_online_cpus() > 1) {
 845                 printk(KERN_ERR PFX "More than 1 CPU detected, longhaul disabled.\n");
 846                 return -ENODEV;
 847         }
 848 #endif
 849 #ifdef CONFIG_X86_IO_APIC
 850         if (cpu_has_apic) {
 851                 printk(KERN_ERR PFX "APIC detected. Longhaul is currently broken in this configuration.\n");
 852                 return -ENODEV;
 853         }
 854 #endif
 855         switch (c->x86_model) {
 856         case 6 ... 9:
 857                 return cpufreq_register_driver(&longhaul_driver);
 858         case 10:
 859                 printk(KERN_ERR PFX "Use acpi-cpufreq driver for VIA C7\n");
 860         default:
 861                 ;;
 862         }
 863
 864         return -ENODEV;
 865 }
 866
 867
 868 static void __exit longhaul_exit(void)
 869 {
 870         int i;
 871
 872         for (i=0; i < numscales; i++) {
 873                 if (clock_ratio[i] == maxmult) {
 874                         longhaul_setstate(i);
 875                         break;
 876                 }
 877         }
 878
 879         cpufreq_unregister_driver(&longhaul_driver);
 880         kfree(longhaul_table);
 881 }
 882
 883 module_param (scale_voltage, int, 0644);
 884 MODULE_PARM_DESC(scale_voltage, "Scale voltage of processor");
 885
 886 MODULE_AUTHOR ("Dave Jones <davej@codemonkey.org.uk>");
 887 MODULE_DESCRIPTION ("Longhaul driver for VIA Cyrix processors.");
 888 MODULE_LICENSE ("GPL");
 889
 890 late_initcall(longhaul_init);
 891 module_exit(longhaul_exit);