diff options
Diffstat (limited to 'arch/x86/cpu/slimbootloader/slimbootloader.c')
| -rw-r--r-- | arch/x86/cpu/slimbootloader/slimbootloader.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/arch/x86/cpu/slimbootloader/slimbootloader.c b/arch/x86/cpu/slimbootloader/slimbootloader.c index 9f3a61ec61..e6b174ca88 100644 --- a/arch/x86/cpu/slimbootloader/slimbootloader.c +++ b/arch/x86/cpu/slimbootloader/slimbootloader.c @@ -4,9 +4,46 @@ */ #include <common.h> +#include <asm/arch/slimbootloader.h> + +DECLARE_GLOBAL_DATA_PTR; + +/** + * This sets tsc_base and clock_rate for early_timer and tsc_timer. + * The performance info guid hob has all performance timestamp data, but + * the only tsc frequency info is used for the timer driver for now. + * + * Slim Bootloader already calibrated TSC and provides it to U-Boot. + * Therefore, U-Boot does not have to re-calibrate TSC. + * Configuring tsc_base and clock_rate here makes x86 tsc_timer driver + * bypass TSC calibration and use the provided TSC frequency. + */ +static void tsc_init(void) +{ + struct sbl_performance_info *data; + const efi_guid_t guid = SBL_PERFORMANCE_INFO_GUID; + + if (!gd->arch.hob_list) + panic("hob list not found!"); + + gd->arch.tsc_base = rdtsc(); + debug("tsc_base=0x%llx\n", gd->arch.tsc_base); + + data = hob_get_guid_hob_data(gd->arch.hob_list, NULL, &guid); + if (!data) { + debug("performance info hob not found\n"); + return; + } + + /* frequency is in KHz, so to Hz */ + gd->arch.clock_rate = data->frequency * 1000; + debug("freq=0x%lx\n", gd->arch.clock_rate); +} int arch_cpu_init(void) { + tsc_init(); + return x86_cpu_init_f(); } |