diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/timer/Kconfig | 14 | ||||
| -rw-r--r-- | drivers/timer/tsc_timer.c | 3 |
2 files changed, 16 insertions, 1 deletions
diff --git a/drivers/timer/Kconfig b/drivers/timer/Kconfig index 5f4bc6edb6..41f9755133 100644 --- a/drivers/timer/Kconfig +++ b/drivers/timer/Kconfig @@ -174,6 +174,20 @@ config X86_TSC_TIMER help Select this to enable Time-Stamp Counter (TSC) timer for x86. +config X86_TSC_READ_BASE + bool "Read the TSC timer base on start-up" + depends on X86_TSC_TIMER + help + On x86 platforms the TSC timer tick starts at the value 0 on reset. + This it makes no sense to read the timer on boot and use that as the + base, since we will miss some time taken to load U-Boot, etc. This + delay is controlled by the SoC and we cannot reduce it, but for + bootstage we want to record the time since reset as accurately as + possible. + + The only exception is when U-Boot is used as a secondary bootloader, + where this option should be enabled. + config MTK_TIMER bool "MediaTek timer support" depends on TIMER diff --git a/drivers/timer/tsc_timer.c b/drivers/timer/tsc_timer.c index 0df551f94c..813817f467 100644 --- a/drivers/timer/tsc_timer.c +++ b/drivers/timer/tsc_timer.c @@ -397,7 +397,8 @@ static void tsc_timer_ensure_setup(bool early) { if (gd->arch.tsc_inited) return; - gd->arch.tsc_base = rdtsc(); + if (IS_ENABLED(CONFIG_X86_TSC_READ_BASE)) + gd->arch.tsc_base = rdtsc(); if (!gd->arch.clock_rate) { unsigned long fast_calibrate; |