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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 <arch/early_variables.h>
#include <cpu/x86/msr.h>
#include <cpu/x86/tsc.h>
#include <cpu/intel/speedstep.h>
#include <cpu/intel/fsb.h>
#include <console/console.h>
#include <commonlib/helpers.h>
#include <delay.h>
static u32 g_timer_fsb CAR_GLOBAL;
static u32 g_timer_tsc CAR_GLOBAL;
/* This is not an architectural MSR. */
#define MSR_PLATFORM_INFO 0xce
static int get_fsb_tsc(int *fsb, int *ratio)
{
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 };
static const short rangeley_fsb[4] = { 83, 100, 133, 116 };
msr_t msr;
get_fms(&c, cpuid_eax(1));
switch (c.x86) {
case 0x6:
switch (c.x86_model) {
case 0xe: /* Core Solo/Duo */
case 0x1c: /* Atom */
*fsb = core_fsb[rdmsr(MSR_FSB_FREQ).lo & 7];
*ratio = (rdmsr(IA32_PERF_STATUS).hi >> 8) & 0x1f;
break;
case 0xf: /* Core 2 or Xeon */
case 0x17: /* Enhanced Core */
*fsb = core2_fsb[rdmsr(MSR_FSB_FREQ).lo & 7];
*ratio = (rdmsr(IA32_PERF_STATUS).hi >> 8) & 0x1f;
break;
case 0x25: /* Nehalem BCLK fixed at 133MHz */
*fsb = 133;
*ratio = (rdmsr(MSR_PLATFORM_INFO).lo >> 8) & 0xff;
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 */
*fsb = 100;
*ratio = (rdmsr(MSR_PLATFORM_INFO).lo >> 8) & 0xff;
break;
case 0x4d: /* Rangeley */
*fsb = rangeley_fsb[rdmsr(MSR_FSB_FREQ).lo & 3];
*ratio = (rdmsr(MSR_PLATFORM_INFO).lo >> 8) & 0xff;
break;
default:
return -2;
}
break;
case 0xf: /* Netburst */
msr = rdmsr(MSR_EBC_FREQUENCY_ID);
*ratio = msr.lo >> 24;
switch (c.x86_model) {
case 0x2:
*fsb = f2x_fsb[(msr.lo >> 16) & 7];
break;
case 0x3:
case 0x4:
case 0x6:
*fsb = core2_fsb[(msr.lo >> 16) & 7];
break;
default:
return -2;
}
break;
default:
return -2;
}
if (*fsb > 0)
return 0;
return -1;
}
static void resolve_timebase(void)
{
int ret, fsb, ratio;
ret = get_fsb_tsc(&fsb, &ratio);
if (ret == 0) {
u32 tsc = 100 * DIV_ROUND_CLOSEST(ratio * fsb, 100);
car_set_var(g_timer_fsb, fsb);
car_set_var(g_timer_tsc, tsc);
return;
}
if (ret == -1)
printk(BIOS_ERR, "FSB not found\n");
if (ret == -2)
printk(BIOS_ERR, "CPU not supported\n");
/* Set some semi-ridiculous defaults. */
car_set_var(g_timer_fsb, 500);
car_set_var(g_timer_tsc, 5000);
return;
}
u32 get_timer_fsb(void)
{
u32 fsb;
fsb = car_get_var(g_timer_fsb);
if (fsb > 0)
return fsb;
resolve_timebase();
return car_get_var(g_timer_fsb);
}
unsigned long tsc_freq_mhz(void)
{
u32 tsc;
tsc = car_get_var(g_timer_tsc);
if (tsc > 0)
return tsc;
resolve_timebase();
return car_get_var(g_timer_tsc);
}
/**
* @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_timer_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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