From 0d6ddf8da7632e775dde92c9114ac6ace5ca5f14 Mon Sep 17 00:00:00 2001 From: Kyösti Mälkki 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/include/cpu/x86/tsc.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'src/include/cpu') diff --git a/src/include/cpu/x86/tsc.h b/src/include/cpu/x86/tsc.h index dd333e8930..c18f8782f0 100644 --- a/src/include/cpu/x86/tsc.h +++ b/src/include/cpu/x86/tsc.h @@ -63,4 +63,9 @@ static inline uint64_t tsc_to_uint64(tsc_t tstamp) /* Provided by CPU/chipset code for the TSC rate in MHz. */ unsigned long tsc_freq_mhz(void); +static inline int tsc_constant_rate(void) +{ + return !CONFIG(UNKNOWN_TSC_RATE); +} + #endif /* CPU_X86_TSC_H */ -- cgit v1.2.3