diff options
| -rw-r--r-- | arch/x86/cpu/coreboot/Kconfig | 1 | ||||
| -rw-r--r-- | arch/x86/cpu/slimbootloader/Kconfig | 1 | ||||
| -rw-r--r-- | drivers/timer/Kconfig | 14 | ||||
| -rw-r--r-- | drivers/timer/tsc_timer.c | 3 | ||||
| -rw-r--r-- | lib/efi/Kconfig | 1 |
5 files changed, 19 insertions, 1 deletions
diff --git a/arch/x86/cpu/coreboot/Kconfig b/arch/x86/cpu/coreboot/Kconfig index 93f61f2fa4..c8e6a889d0 100644 --- a/arch/x86/cpu/coreboot/Kconfig +++ b/arch/x86/cpu/coreboot/Kconfig @@ -24,5 +24,6 @@ config SYS_COREBOOT imply CMD_CBFS imply FS_CBFS imply CBMEM_CONSOLE + imply X86_TSC_READ_BASE endif diff --git a/arch/x86/cpu/slimbootloader/Kconfig b/arch/x86/cpu/slimbootloader/Kconfig index 3ea4c9958c..58a9ca01a9 100644 --- a/arch/x86/cpu/slimbootloader/Kconfig +++ b/arch/x86/cpu/slimbootloader/Kconfig @@ -17,3 +17,4 @@ config SYS_SLIMBOOTLOADER imply USB_EHCI_HCD imply USB_XHCI_HCD imply E1000 + imply X86_TSC_READ_BASE 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; diff --git a/lib/efi/Kconfig b/lib/efi/Kconfig index 919e314a0c..93b8564492 100644 --- a/lib/efi/Kconfig +++ b/lib/efi/Kconfig @@ -1,6 +1,7 @@ config EFI bool "Support running U-Boot from EFI" depends on X86 + imply X86_TSC_READ_BASE help U-Boot can be started from EFI on certain platforms. This allows EFI to perform most of the system init and then jump to U-Boot for |