0d6ddf8da7
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 <kyosti.malkki@gmail.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/33928 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Aaron Durbin <adurbin@chromium.org>
32 lines
915 B
C
32 lines
915 B
C
/*
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* This file is part of the coreboot project.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <cpu/x86/tsc.h>
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#include <timestamp.h>
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uint64_t timestamp_get(void)
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{
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return rdtscll();
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}
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int timestamp_tick_freq_mhz(void)
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{
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/* Chipsets that have a constant TSC provide this value correctly. */
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if (tsc_constant_rate())
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return tsc_freq_mhz();
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/* Filling tick_freq_mhz = 0 in timestamps-table will trigger
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* userspace utility to try deduce it from the running system.
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*/
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return 0;
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}
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