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powernow-k7.c

/*
 *  AMD K7 Powernow driver.
 *  (C) 2003 Dave Jones <davej@codemonkey.org.uk> on behalf of SuSE Labs.
 *  (C) 2003-2004 Dave Jones <davej@redhat.com>
 *
 *  Licensed under the terms of the GNU GPL License version 2.
 *  Based upon datasheets & sample CPUs kindly provided by AMD.
 *
 * Errata 5: Processor may fail to execute a FID/VID change in presence of interrupt.
 * - We cli/sti on stepping A0 CPUs around the FID/VID transition.
 * Errata 15: Processors with half frequency multipliers may hang upon wakeup from disconnect.
 * - We disable half multipliers if ACPI is used on A0 stepping CPUs.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/dmi.h>

#include <asm/msr.h>
#include <asm/timer.h>
#include <asm/timex.h>
#include <asm/io.h>
#include <asm/system.h>

#ifdef CONFIG_X86_POWERNOW_K7_ACPI
#include <linux/acpi.h>
#include <acpi/processor.h>
#endif

#include "powernow-k7.h"

#define PFX "powernow: "


struct psb_s {
      u8 signature[10];
      u8 tableversion;
      u8 flags;
      u16 settlingtime;
      u8 reserved1;
      u8 numpst;
};

struct pst_s {
      u32 cpuid;
      u8 fsbspeed;
      u8 maxfid;
      u8 startvid;
      u8 numpstates;
};

#ifdef CONFIG_X86_POWERNOW_K7_ACPI
union powernow_acpi_control_t {
      struct {
            unsigned long fid:5,
            vid:5,
            sgtc:20,
            res1:2;
      } bits;
      unsigned long val;
};
#endif

#ifdef CONFIG_CPU_FREQ_DEBUG
/* divide by 1000 to get VCore voltage in V. */
static const int mobile_vid_table[32] = {
    2000, 1950, 1900, 1850, 1800, 1750, 1700, 1650,
    1600, 1550, 1500, 1450, 1400, 1350, 1300, 0,
    1275, 1250, 1225, 1200, 1175, 1150, 1125, 1100,
    1075, 1050, 1025, 1000, 975, 950, 925, 0,
};
#endif

/* divide by 10 to get FID. */
static const int fid_codes[32] = {
    110, 115, 120, 125, 50, 55, 60, 65,
    70, 75, 80, 85, 90, 95, 100, 105,
    30, 190, 40, 200, 130, 135, 140, 210,
    150, 225, 160, 165, 170, 180, -1, -1,
};

/* This parameter is used in order to force ACPI instead of legacy method for
 * configuration purpose.
 */

static int acpi_force;

static struct cpufreq_frequency_table *powernow_table;

static unsigned int can_scale_bus;
static unsigned int can_scale_vid;
static unsigned int minimum_speed=-1;
static unsigned int maximum_speed;
static unsigned int number_scales;
static unsigned int fsb;
static unsigned int latency;
static char have_a0;

#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "powernow-k7", msg)

static int check_fsb(unsigned int fsbspeed)
{
      int delta;
      unsigned int f = fsb / 1000;

      delta = (fsbspeed > f) ? fsbspeed - f : f - fsbspeed;
      return (delta < 5);
}

static int check_powernow(void)
{
      struct cpuinfo_x86 *c = &cpu_data(0);
      unsigned int maxei, eax, ebx, ecx, edx;

      if ((c->x86_vendor != X86_VENDOR_AMD) || (c->x86 !=6)) {
#ifdef MODULE
            printk (KERN_INFO PFX "This module only works with AMD K7 CPUs\n");
#endif
            return 0;
      }

      /* Get maximum capabilities */
      maxei = cpuid_eax (0x80000000);
      if (maxei < 0x80000007) {     /* Any powernow info ? */
#ifdef MODULE
            printk (KERN_INFO PFX "No powernow capabilities detected\n");
#endif
            return 0;
      }

      if ((c->x86_model == 6) && (c->x86_mask == 0)) {
            printk (KERN_INFO PFX "K7 660[A0] core detected, enabling errata workarounds\n");
            have_a0 = 1;
      }

      cpuid(0x80000007, &eax, &ebx, &ecx, &edx);

      /* Check we can actually do something before we say anything.*/
      if (!(edx & (1 << 1 | 1 << 2)))
            return 0;

      printk (KERN_INFO PFX "PowerNOW! Technology present. Can scale: ");

      if (edx & 1 << 1) {
            printk ("frequency");
            can_scale_bus=1;
      }

      if ((edx & (1 << 1 | 1 << 2)) == 0x6)
            printk (" and ");

      if (edx & 1 << 2) {
            printk ("voltage");
            can_scale_vid=1;
      }

      printk (".\n");
      return 1;
}


static int get_ranges (unsigned char *pst)
{
      unsigned int j;
      unsigned int speed;
      u8 fid, vid;

      powernow_table = kzalloc((sizeof(struct cpufreq_frequency_table) * (number_scales + 1)), GFP_KERNEL);
      if (!powernow_table)
            return -ENOMEM;

      for (j=0 ; j < number_scales; j++) {
            fid = *pst++;

            powernow_table[j].frequency = (fsb * fid_codes[fid]) / 10;
            powernow_table[j].index = fid; /* lower 8 bits */

            speed = powernow_table[j].frequency;

            if ((fid_codes[fid] % 10)==5) {
#ifdef CONFIG_X86_POWERNOW_K7_ACPI
                  if (have_a0 == 1)
                        powernow_table[j].frequency = CPUFREQ_ENTRY_INVALID;
#endif
            }

            if (speed < minimum_speed)
                  minimum_speed = speed;
            if (speed > maximum_speed)
                  maximum_speed = speed;

            vid = *pst++;
            powernow_table[j].index |= (vid << 8); /* upper 8 bits */

            dprintk ("   FID: 0x%x (%d.%dx [%dMHz])  "
                   "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
                   fid_codes[fid] % 10, speed/1000, vid,
                   mobile_vid_table[vid]/1000,
                   mobile_vid_table[vid]%1000);
      }
      powernow_table[number_scales].frequency = CPUFREQ_TABLE_END;
      powernow_table[number_scales].index = 0;

      return 0;
}


static void change_FID(int fid)
{
      union msr_fidvidctl fidvidctl;

      rdmsrl (MSR_K7_FID_VID_CTL, fidvidctl.val);
      if (fidvidctl.bits.FID != fid) {
            fidvidctl.bits.SGTC = latency;
            fidvidctl.bits.FID = fid;
            fidvidctl.bits.VIDC = 0;
            fidvidctl.bits.FIDC = 1;
            wrmsrl (MSR_K7_FID_VID_CTL, fidvidctl.val);
      }
}


static void change_VID(int vid)
{
      union msr_fidvidctl fidvidctl;

      rdmsrl (MSR_K7_FID_VID_CTL, fidvidctl.val);
      if (fidvidctl.bits.VID != vid) {
            fidvidctl.bits.SGTC = latency;
            fidvidctl.bits.VID = vid;
            fidvidctl.bits.FIDC = 0;
            fidvidctl.bits.VIDC = 1;
            wrmsrl (MSR_K7_FID_VID_CTL, fidvidctl.val);
      }
}


static void change_speed (unsigned int index)
{
      u8 fid, vid;
      struct cpufreq_freqs freqs;
      union msr_fidvidstatus fidvidstatus;
      int cfid;

      /* fid are the lower 8 bits of the index we stored into
       * the cpufreq frequency table in powernow_decode_bios,
       * vid are the upper 8 bits.
       */

      fid = powernow_table[index].index & 0xFF;
      vid = (powernow_table[index].index & 0xFF00) >> 8;

      freqs.cpu = 0;

      rdmsrl (MSR_K7_FID_VID_STATUS, fidvidstatus.val);
      cfid = fidvidstatus.bits.CFID;
      freqs.old = fsb * fid_codes[cfid] / 10;

      freqs.new = powernow_table[index].frequency;

      cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);

      /* Now do the magic poking into the MSRs.  */

      if (have_a0 == 1) /* A0 errata 5 */
            local_irq_disable();

      if (freqs.old > freqs.new) {
            /* Going down, so change FID first */
            change_FID(fid);
            change_VID(vid);
      } else {
            /* Going up, so change VID first */
            change_VID(vid);
            change_FID(fid);
      }


      if (have_a0 == 1)
            local_irq_enable();

      cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
}


#ifdef CONFIG_X86_POWERNOW_K7_ACPI

static struct acpi_processor_performance *acpi_processor_perf;

static int powernow_acpi_init(void)
{
      int i;
      int retval = 0;
      union powernow_acpi_control_t pc;

      if (acpi_processor_perf != NULL && powernow_table != NULL) {
            retval = -EINVAL;
            goto err0;
      }

      acpi_processor_perf = kzalloc(sizeof(struct acpi_processor_performance),
                              GFP_KERNEL);
      if (!acpi_processor_perf) {
            retval = -ENOMEM;
            goto err0;
      }

      if (acpi_processor_register_performance(acpi_processor_perf, 0)) {
            retval = -EIO;
            goto err1;
      }

      if (acpi_processor_perf->control_register.space_id != ACPI_ADR_SPACE_FIXED_HARDWARE) {
            retval = -ENODEV;
            goto err2;
      }

      if (acpi_processor_perf->status_register.space_id != ACPI_ADR_SPACE_FIXED_HARDWARE) {
            retval = -ENODEV;
            goto err2;
      }

      number_scales = acpi_processor_perf->state_count;

      if (number_scales < 2) {
            retval = -ENODEV;
            goto err2;
      }

      powernow_table = kzalloc((number_scales + 1) * (sizeof(struct cpufreq_frequency_table)), GFP_KERNEL);
      if (!powernow_table) {
            retval = -ENOMEM;
            goto err2;
      }

      pc.val = (unsigned long) acpi_processor_perf->states[0].control;
      for (i = 0; i < number_scales; i++) {
            u8 fid, vid;
            struct acpi_processor_px *state =
                  &acpi_processor_perf->states[i];
            unsigned int speed, speed_mhz;

            pc.val = (unsigned long) state->control;
            dprintk ("acpi:  P%d: %d MHz %d mW %d uS control %08x SGTC %d\n",
                   i,
                   (u32) state->core_frequency,
                   (u32) state->power,
                   (u32) state->transition_latency,
                   (u32) state->control,
                   pc.bits.sgtc);

            vid = pc.bits.vid;
            fid = pc.bits.fid;

            powernow_table[i].frequency = fsb * fid_codes[fid] / 10;
            powernow_table[i].index = fid; /* lower 8 bits */
            powernow_table[i].index |= (vid << 8); /* upper 8 bits */

            speed = powernow_table[i].frequency;
            speed_mhz = speed / 1000;

            /* processor_perflib will multiply the MHz value by 1000 to
             * get a KHz value (e.g. 1266000). However, powernow-k7 works
             * with true KHz values (e.g. 1266768). To ensure that all
             * powernow frequencies are available, we must ensure that
             * ACPI doesn't restrict them, so we round up the MHz value
             * to ensure that perflib's computed KHz value is greater than
             * or equal to powernow's KHz value.
             */
            if (speed % 1000 > 0)
                  speed_mhz++;

            if ((fid_codes[fid] % 10)==5) {
                  if (have_a0 == 1)
                        powernow_table[i].frequency = CPUFREQ_ENTRY_INVALID;
            }

            dprintk ("   FID: 0x%x (%d.%dx [%dMHz])  "
                   "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
                   fid_codes[fid] % 10, speed_mhz, vid,
                   mobile_vid_table[vid]/1000,
                   mobile_vid_table[vid]%1000);

            if (state->core_frequency != speed_mhz) {
                  state->core_frequency = speed_mhz;
                  dprintk("   Corrected ACPI frequency to %d\n",
                        speed_mhz);
            }

            if (latency < pc.bits.sgtc)
                  latency = pc.bits.sgtc;

            if (speed < minimum_speed)
                  minimum_speed = speed;
            if (speed > maximum_speed)
                  maximum_speed = speed;
      }

      powernow_table[i].frequency = CPUFREQ_TABLE_END;
      powernow_table[i].index = 0;

      /* notify BIOS that we exist */
      acpi_processor_notify_smm(THIS_MODULE);

      return 0;

err2:
      acpi_processor_unregister_performance(acpi_processor_perf, 0);
err1:
      kfree(acpi_processor_perf);
err0:
      printk(KERN_WARNING PFX "ACPI perflib can not be used in this platform\n");
      acpi_processor_perf = NULL;
      return retval;
}
#else
static int powernow_acpi_init(void)
{
      printk(KERN_INFO PFX "no support for ACPI processor found."
             "  Please recompile your kernel with ACPI processor\n");
      return -EINVAL;
}
#endif

static int powernow_decode_bios (int maxfid, int startvid)
{
      struct psb_s *psb;
      struct pst_s *pst;
      unsigned int i, j;
      unsigned char *p;
      unsigned int etuple;
      unsigned int ret;

      etuple = cpuid_eax(0x80000001);

      for (i=0xC0000; i < 0xffff0 ; i+=16) {

            p = phys_to_virt(i);

            if (memcmp(p, "AMDK7PNOW!",  10) == 0){
                  dprintk ("Found PSB header at %p\n", p);
                  psb = (struct psb_s *) p;
                  dprintk ("Table version: 0x%x\n", psb->tableversion);
                  if (psb->tableversion != 0x12) {
                        printk (KERN_INFO PFX "Sorry, only v1.2 tables supported right now\n");
                        return -ENODEV;
                  }

                  dprintk ("Flags: 0x%x\n", psb->flags);
                  if ((psb->flags & 1)==0) {
                        dprintk ("Mobile voltage regulator\n");
                  } else {
                        dprintk ("Desktop voltage regulator\n");
                  }

                  latency = psb->settlingtime;
                  if (latency < 100) {
                        printk (KERN_INFO PFX "BIOS set settling time to %d microseconds."
                                    "Should be at least 100. Correcting.\n", latency);
                        latency = 100;
                  }
                  dprintk ("Settling Time: %d microseconds.\n", psb->settlingtime);
                  dprintk ("Has %d PST tables. (Only dumping ones relevant to this CPU).\n", psb->numpst);

                  p += sizeof (struct psb_s);

                  pst = (struct pst_s *) p;

                  for (j=0; j<psb->numpst; j++) {
                        pst = (struct pst_s *) p;
                        number_scales = pst->numpstates;

                        if ((etuple == pst->cpuid) && check_fsb(pst->fsbspeed) &&
                            (maxfid==pst->maxfid) && (startvid==pst->startvid))
                        {
                              dprintk ("PST:%d (@%p)\n", j, pst);
                              dprintk (" cpuid: 0x%x  fsb: %d  maxFID: 0x%x  startvid: 0x%x\n",
                                     pst->cpuid, pst->fsbspeed, pst->maxfid, pst->startvid);

                              ret = get_ranges ((char *) pst + sizeof (struct pst_s));
                              return ret;
                        } else {
                              unsigned int k;
                              p = (char *) pst + sizeof (struct pst_s);
                              for (k=0; k<number_scales; k++)
                                    p+=2;
                        }
                  }
                  printk (KERN_INFO PFX "No PST tables match this cpuid (0x%x)\n", etuple);
                  printk (KERN_INFO PFX "This is indicative of a broken BIOS.\n");

                  return -EINVAL;
            }
            p++;
      }

      return -ENODEV;
}


static int powernow_target (struct cpufreq_policy *policy,
                      unsigned int target_freq,
                      unsigned int relation)
{
      unsigned int newstate;

      if (cpufreq_frequency_table_target(policy, powernow_table, target_freq, relation, &newstate))
            return -EINVAL;

      change_speed(newstate);

      return 0;
}


static int powernow_verify (struct cpufreq_policy *policy)
{
      return cpufreq_frequency_table_verify(policy, powernow_table);
}

/*
 * We use the fact that the bus frequency is somehow
 * a multiple of 100000/3 khz, then we compute sgtc according
 * to this multiple.
 * That way, we match more how AMD thinks all of that work.
 * We will then get the same kind of behaviour already tested under
 * the "well-known" other OS.
 */
static int __init fixup_sgtc(void)
{
      unsigned int sgtc;
      unsigned int m;

      m = fsb / 3333;
      if ((m % 10) >= 5)
            m += 5;

      m /= 10;

      sgtc = 100 * m * latency;
      sgtc = sgtc / 3;
      if (sgtc > 0xfffff) {
            printk(KERN_WARNING PFX "SGTC too large %d\n", sgtc);
            sgtc = 0xfffff;
      }
      return sgtc;
}

static unsigned int powernow_get(unsigned int cpu)
{
      union msr_fidvidstatus fidvidstatus;
      unsigned int cfid;

      if (cpu)
            return 0;
      rdmsrl (MSR_K7_FID_VID_STATUS, fidvidstatus.val);
      cfid = fidvidstatus.bits.CFID;

      return (fsb * fid_codes[cfid] / 10);
}


static int __init acer_cpufreq_pst(const struct dmi_system_id *d)
{
      printk(KERN_WARNING "%s laptop with broken PST tables in BIOS detected.\n", d->ident);
      printk(KERN_WARNING "You need to downgrade to 3A21 (09/09/2002), or try a newer BIOS than 3A71 (01/20/2003)\n");
      printk(KERN_WARNING "cpufreq scaling has been disabled as a result of this.\n");
      return 0;
}

/*
 * Some Athlon laptops have really fucked PST tables.
 * A BIOS update is all that can save them.
 * Mention this, and disable cpufreq.
 */
static struct dmi_system_id __initdata powernow_dmi_table[] = {
      {
            .callback = acer_cpufreq_pst,
            .ident = "Acer Aspire",
            .matches = {
                  DMI_MATCH(DMI_SYS_VENDOR, "Insyde Software"),
                  DMI_MATCH(DMI_BIOS_VERSION, "3A71"),
            },
      },
      { }
};

static int __init powernow_cpu_init (struct cpufreq_policy *policy)
{
      union msr_fidvidstatus fidvidstatus;
      int result;

      if (policy->cpu != 0)
            return -ENODEV;

      rdmsrl (MSR_K7_FID_VID_STATUS, fidvidstatus.val);

      recalibrate_cpu_khz();

      fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.CFID];
      if (!fsb) {
            printk(KERN_WARNING PFX "can not determine bus frequency\n");
            return -EINVAL;
      }
      dprintk("FSB: %3dMHz\n", fsb/1000);

      if (dmi_check_system(powernow_dmi_table) || acpi_force) {
            printk (KERN_INFO PFX "PSB/PST known to be broken.  Trying ACPI instead\n");
            result = powernow_acpi_init();
      } else {
            result = powernow_decode_bios(fidvidstatus.bits.MFID, fidvidstatus.bits.SVID);
            if (result) {
                  printk (KERN_INFO PFX "Trying ACPI perflib\n");
                  maximum_speed = 0;
                  minimum_speed = -1;
                  latency = 0;
                  result = powernow_acpi_init();
                  if (result) {
                        printk (KERN_INFO PFX "ACPI and legacy methods failed\n");
                        printk (KERN_INFO PFX "See http://www.codemonkey.org.uk/projects/cpufreq/powernow-k7.html\n");
                  }
            } else {
                  /* SGTC use the bus clock as timer */
                  latency = fixup_sgtc();
                  printk(KERN_INFO PFX "SGTC: %d\n", latency);
            }
      }

      if (result)
            return result;

      printk (KERN_INFO PFX "Minimum speed %d MHz. Maximum speed %d MHz.\n",
                        minimum_speed/1000, maximum_speed/1000);

      policy->cpuinfo.transition_latency = cpufreq_scale(2000000UL, fsb, latency);

      policy->cur = powernow_get(0);

      cpufreq_frequency_table_get_attr(powernow_table, policy->cpu);

      return cpufreq_frequency_table_cpuinfo(policy, powernow_table);
}

static int powernow_cpu_exit (struct cpufreq_policy *policy) {
      cpufreq_frequency_table_put_attr(policy->cpu);

#ifdef CONFIG_X86_POWERNOW_K7_ACPI
      if (acpi_processor_perf) {
            acpi_processor_unregister_performance(acpi_processor_perf, 0);
            kfree(acpi_processor_perf);
      }
#endif

      kfree(powernow_table);
      return 0;
}

static struct freq_attr* powernow_table_attr[] = {
      &cpufreq_freq_attr_scaling_available_freqs,
      NULL,
};

static struct cpufreq_driver powernow_driver = {
      .verify     = powernow_verify,
      .target     = powernow_target,
      .get  = powernow_get,
      .init = powernow_cpu_init,
      .exit = powernow_cpu_exit,
      .name = "powernow-k7",
      .owner      = THIS_MODULE,
      .attr = powernow_table_attr,
};

static int __init powernow_init (void)
{
      if (check_powernow()==0)
            return -ENODEV;
      return cpufreq_register_driver(&powernow_driver);
}


static void __exit powernow_exit (void)
{
      cpufreq_unregister_driver(&powernow_driver);
}

module_param(acpi_force,  int, 0444);
MODULE_PARM_DESC(acpi_force, "Force ACPI to be used.");

MODULE_AUTHOR ("Dave Jones <davej@codemonkey.org.uk>");
MODULE_DESCRIPTION ("Powernow driver for AMD K7 processors.");
MODULE_LICENSE ("GPL");

late_initcall(powernow_init);
module_exit(powernow_exit);


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