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/*********************************************************************
 *                   GET PROCESSOR CORE SPEED IN KHZ                 *
 *********************************************************************/

static unsigned int pentium3_get_frequency (unsigned int processor)
{
        /* See table 14 of p3_ds.pdf and table 22 of 29834003.pdf */
   struct {
      unsigned int ratio;   /* Frequency Multiplier (x10) */
      u8 bitmap;           /* power on configuration bits
                  [27, 25:22] (in MSR 0x2a) */
   } msr_decode_mult [] = {
      { 30, 0x01 },
      { 35, 0x05 },
      { 40, 0x02 },
      { 45, 0x06 },
      { 50, 0x00 },
      { 55, 0x04 },
      { 60, 0x0b },
      { 65, 0x0f },
      { 70, 0x09 },
      { 75, 0x0d },
      { 80, 0x0a },
      { 85, 0x26 },
      { 90, 0x20 },
      { 100, 0x2b },
      { 0, 0xff }     /* error or unknown value */
   };

   /* PIII(-M) FSB settings: see table b1-b of 24547206.pdf */
   struct {
      unsigned int value;     /* Front Side Bus speed in MHz */
      u8 bitmap;              /* power on configuration bits [18: 19]
                  (in MSR 0x2a) */
   } msr_decode_fsb [] = {
      {  66, 0x0 },
      { 100, 0x2 },
      { 133, 0x1 },
      {   0, 0xff}
   };

   u32     msr_lo, msr_tmp;
   int     i = 0, j = 0;

   /* read MSR 0x2a - we only need the low 32 bits */
   rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_tmp);
   dprintk("P3 - MSR_IA32_EBL_CR_POWERON: 0x%x 0x%x\n", msr_lo, msr_tmp);
   msr_tmp = msr_lo;

   /* decode the FSB */
   msr_tmp &= 0x00c0000;
   msr_tmp >>= 18;
   while (msr_tmp != msr_decode_fsb[i].bitmap) {
      if (msr_decode_fsb[i].bitmap == 0xff)
         return 0;
      i++;
   }

   /* decode the multiplier */
   if (processor == SPEEDSTEP_PROCESSOR_PIII_C_EARLY) {
      dprintk("workaround for early PIIIs\n");
      msr_lo &= 0x03c00000;
   } else
      msr_lo &= 0x0bc00000;
   msr_lo >>= 22;
   while (msr_lo != msr_decode_mult[j].bitmap) {
      if (msr_decode_mult[j].bitmap == 0xff)
         return 0;
      j++;
   }

   dprintk("speed is %u\n", (msr_decode_mult[j].ratio * msr_decode_fsb[i].value * 100));

   return (msr_decode_mult[j].ratio * msr_decode_fsb[i].value * 100);
}