diff options
Diffstat (limited to 'arch/x86/kernel/tsc_msr.c')
| -rw-r--r-- | arch/x86/kernel/tsc_msr.c | 36 |
1 files changed, 10 insertions, 26 deletions
diff --git a/arch/x86/kernel/tsc_msr.c b/arch/x86/kernel/tsc_msr.c index f7ba44b89cc4..4110f723fd0f 100644 --- a/arch/x86/kernel/tsc_msr.c +++ b/arch/x86/kernel/tsc_msr.c @@ -1,14 +1,5 @@ /* - * tsc_msr.c - MSR based TSC calibration on Intel Atom SoC platforms. - * - * TSC in Intel Atom SoC runs at a constant rate which can be figured - * by this formula: - * <maximum core-clock to bus-clock ratio> * <maximum resolved frequency> - * See Intel 64 and IA-32 System Programming Guid section 16.12 and 30.11.5 - * for details. - * Especially some Intel Atom SoCs don't have PIT(i8254) or HPET, so MSR - * based calibration is the only option. - * + * tsc_msr.c - TSC frequency enumeration via MSR * * Copyright (C) 2013 Intel Corporation * Author: Bin Gao <bin.gao@intel.com> @@ -22,17 +13,10 @@ #include <asm/apic.h> #include <asm/param.h> -/* CPU reference clock frequency: in KHz */ -#define FREQ_83 83200 -#define FREQ_100 99840 -#define FREQ_133 133200 -#define FREQ_166 166400 - #define MAX_NUM_FREQS 8 /* - * According to Intel 64 and IA-32 System Programming Guide, - * if MSR_PERF_STAT[31] is set, the maximum resolved bus ratio can be + * If MSR_PERF_STAT[31] is set, the maximum resolved bus ratio can be * read in MSR_PLATFORM_ID[12:8], otherwise in MSR_PERF_STAT[44:40]. * Unfortunately some Intel Atom SoCs aren't quite compliant to this, * so we need manually differentiate SoC families. This is what the @@ -47,15 +31,15 @@ struct freq_desc { static struct freq_desc freq_desc_tables[] = { /* PNW */ - { 6, 0x27, 0, { 0, 0, 0, 0, 0, FREQ_100, 0, FREQ_83 } }, + { 6, 0x27, 0, { 0, 0, 0, 0, 0, 99840, 0, 83200 } }, /* CLV+ */ - { 6, 0x35, 0, { 0, FREQ_133, 0, 0, 0, FREQ_100, 0, FREQ_83 } }, - /* TNG */ - { 6, 0x4a, 1, { 0, FREQ_100, FREQ_133, 0, 0, 0, 0, 0 } }, - /* VLV2 */ - { 6, 0x37, 1, { FREQ_83, FREQ_100, FREQ_133, FREQ_166, 0, 0, 0, 0 } }, - /* ANN */ - { 6, 0x5a, 1, { FREQ_83, FREQ_100, FREQ_133, FREQ_100, 0, 0, 0, 0 } }, + { 6, 0x35, 0, { 0, 133200, 0, 0, 0, 99840, 0, 83200 } }, + /* TNG - Intel Atom processor Z3400 series */ + { 6, 0x4a, 1, { 0, 99840, 133200, 0, 0, 0, 0, 0 } }, + /* VLV2 - Intel Atom processor E3000, Z3600, Z3700 series */ + { 6, 0x37, 1, { 83200, 99840, 133200, 166400, 0, 0, 0, 0 } }, + /* ANN - Intel Atom processor Z3500 series */ + { 6, 0x5a, 1, { 83200, 99840, 133200, 99840, 0, 0, 0, 0 } }, }; static int match_cpu(u8 family, u8 model) |