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/*
* This file is part of the coreboot project.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <cpu/cpu.h>
#include <cpu/x86/msr.h>
#include <cpu/intel/speedstep.h>
#include <cpu/intel/fsb.h>
#include <console/console.h>
#include <commonlib/helpers.h>
int get_ia32_fsb(void)
{
struct cpuinfo_x86 c;
static const short core_fsb[8] = { -1, 133, -1, 166, -1, 100, -1, -1 };
static const short core2_fsb[8] = { 266, 133, 200, 166, 333, 100, 400, -1 };
static const short f2x_fsb[8] = { 100, 133, 200, 166, 333, -1, -1, -1 };
msr_t msr;
int ret = -2;
get_fms(&c, cpuid_eax(1));
switch (c.x86) {
case 0x6:
switch (c.x86_model) {
case 0xe: /* Core Solo/Duo */
case 0x1c: /* Atom */
ret = core_fsb[rdmsr(MSR_FSB_FREQ).lo & 7];
break;
case 0xf: /* Core 2 or Xeon */
case 0x17: /* Enhanced Core */
ret = core2_fsb[rdmsr(MSR_FSB_FREQ).lo & 7];
break;
case 0x2a: /* SandyBridge BCLK fixed at 100MHz*/
case 0x3a: /* IvyBridge BCLK fixed at 100MHz*/
case 0x3c: /* Haswell BCLK fixed at 100MHz */
case 0x45: /* Haswell-ULT BCLK fixed at 100MHz */
ret = 100;
break;
}
break;
case 0xf: /* Netburst */
msr = rdmsr(MSR_EBC_FREQUENCY_ID);
switch (c.x86_model) {
case 0x2:
ret = f2x_fsb[(msr.lo >> 16) & 7];
break;
case 0x3:
case 0x4:
case 0x6:
ret = core2_fsb[(msr.lo >> 16) & 7];
break;
}
}
if (ret == -1)
printk(BIOS_ERR, "FSB not found\n");
if (ret == -2)
printk(BIOS_ERR, "CPU not supported\n");
return ret;
}
/**
* @brief Returns three times the FSB clock in MHz
*
* The result of calculations with the returned value shall be divided by 3.
* This helps to avoid rounding errors.
*/
int get_ia32_fsb_x3(void)
{
const int fsb = get_ia32_fsb();
if (fsb > 0)
return 100 * DIV_ROUND_CLOSEST(3 * fsb, 100);
printk(BIOS_ERR, "FSB not supported or not found\n");
return -1;
}
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