From 0d6ddf8da7632e775dde92c9114ac6ace5ca5f14 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ky=C3=B6sti=20M=C3=A4lkki?= Date: Thu, 31 Oct 2019 14:52:20 +0200 Subject: cpu/x86/tsc: Flip and rename TSC_CONSTANT_RATE to UNKNOWN_TSC_RATE MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The x86 timers are a bit of a mess. Cases where different stages use different counters and timestamps use different counters from udelays. The original intention was to only flip TSC_CONSTANT_RATE Kconfig to NOT_CONSTANT_TSC_RATE. The name would be incorrect though, those counters do run with a constant rate but we just lack tsc_freq_mhz() implementation for three platforms. Note that for boards with UNKNOWN_TSC_RATE=y, each stage will have a slow run of calibrate_tsc_with_pit(). This is easy enough to fix with followup implementation of tsc_freq_mhz() for the platforms. Implementations with LAPIC_MONOTONIC_TIMER typically will not have tsc_freq_mhz() implemented and default to UNKNOWN_TSC_RATE. However, as they don't use TSC for udelay() the slow calibrate_tsc_with_pit() is avoided. Because x86/tsc_delay.tsc was using two different guards and nb/via/vx900 claimed UDELAY_TSC, but pulled UDELAY_IO implementation, we also switch that romstage to use UDELAY_TSC. Change-Id: I1690cb80295d6b006b75ed69edea28899b674b68 Signed-off-by: Kyösti Mälkki Reviewed-on: https://review.coreboot.org/c/coreboot/+/33928 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin --- src/cpu/via/nano/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'src/cpu/via') diff --git a/src/cpu/via/nano/Kconfig b/src/cpu/via/nano/Kconfig index 4b96c7ce82..14acfd5662 100644 --- a/src/cpu/via/nano/Kconfig +++ b/src/cpu/via/nano/Kconfig @@ -25,6 +25,7 @@ config CPU_SPECIFIC_OPTIONS select ARCH_RAMSTAGE_X86_32 select UDELAY_TSC select TSC_MONOTONIC_TIMER + select UNKNOWN_TSC_RATE select MMX select SSE2 select SUPPORT_CPU_UCODE_IN_CBFS -- cgit v1.2.3