diff options
| author | Aaron Durbin <adurbin@chromium.org> | 2013-10-11 00:44:06 -0500 |
|---|---|---|
| committer | Aaron Durbin <adurbin@google.com> | 2014-02-16 20:37:03 +0100 |
| commit | 9d9d7f04296e2c6de5bd10ee4bff1a496006f9e1 (patch) | |
| tree | 2042e72caa55e408d5ab23f232449d9b744b1040 /src/soc/intel | |
| parent | 6f6a249a75927476ba5e06bb2b0a0138e0cf63ea (diff) | |
| download | coreboot-9d9d7f04296e2c6de5bd10ee4bff1a496006f9e1.tar.xz | |
baytrail: fix tsc rate
Despite some references to a fixed bclk in some of the
docs the bclk is variable per sku. Therefore, perform
the calculation according to the BSEL_CR_OVERCLOCK_CONTROL
msr which provides the bclk for the cpu cores in Bay Trail.
BUG=chrome-os-partner:23166
BRANCH=None
TEST=Built and booted B3. correctly says: clocks_per_usec: 2133
Change-Id: I55da45d42e7672fdb3b821c8aed7340a6f73dd08
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/172771
Reviewed-by: Shawn Nematbakhsh <shawnn@chromium.org>
Reviewed-on: http://review.coreboot.org/4883
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
Diffstat (limited to 'src/soc/intel')
| -rw-r--r-- | src/soc/intel/baytrail/baytrail/msr.h | 1 | ||||
| -rw-r--r-- | src/soc/intel/baytrail/tsc_freq.c | 21 |
2 files changed, 19 insertions, 3 deletions
diff --git a/src/soc/intel/baytrail/baytrail/msr.h b/src/soc/intel/baytrail/baytrail/msr.h index 7f3b3b26fd..5094f965c7 100644 --- a/src/soc/intel/baytrail/baytrail/msr.h +++ b/src/soc/intel/baytrail/baytrail/msr.h @@ -21,6 +21,7 @@ #define _BAYTRAIL_MSR_H_ #define MSR_IA32_PLATFORM_ID 0x17 +#define MSR_BSEL_CR_OVERCLOCK_CONTROL 0xcd #define MSR_PLATFORM_INFO 0xce #define MSR_IA32_PERF_CTL 0x199 #define MSR_IA32_MISC_ENABLES 0x1a0 diff --git a/src/soc/intel/baytrail/tsc_freq.c b/src/soc/intel/baytrail/tsc_freq.c index 0cf7273b74..e4327318da 100644 --- a/src/soc/intel/baytrail/tsc_freq.c +++ b/src/soc/intel/baytrail/tsc_freq.c @@ -27,14 +27,29 @@ #include <baytrail/romstage.h> #endif - -#define BCLK 100 /* 100 MHz */ unsigned long tsc_freq_mhz(void) { msr_t platform_info; + msr_t clk_info; + unsigned long bclk_khz; platform_info = rdmsr(MSR_PLATFORM_INFO); - return BCLK * ((platform_info.lo >> 8) & 0xff); + clk_info = rdmsr(MSR_BSEL_CR_OVERCLOCK_CONTROL); + switch (clk_info.lo & 0x3) { + case 0: + bclk_khz = 83333; + break; + case 1: + bclk_khz = 100000; + break; + case 2: + bclk_khz = 133333; + break; + case 3: + bclk_khz = 116666; + break; + } + return (bclk_khz * ((platform_info.lo >> 8) & 0xff)) / 1000; } void set_max_freq(void) |