diff options
Diffstat (limited to 'src/cpu/intel/common/fsb.c')
| -rw-r--r-- | src/cpu/intel/common/fsb.c | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/src/cpu/intel/common/fsb.c b/src/cpu/intel/common/fsb.c new file mode 100644 index 0000000000..1f7c391a8f --- /dev/null +++ b/src/cpu/intel/common/fsb.c @@ -0,0 +1,85 @@ +/* + * 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; +} |