a73b93157f
It encourages users from writing to the FSF without giving an address. Linux also prefers to drop that and their checkpatch.pl (that we imported) looks out for that. This is the result of util/scripts/no-fsf-addresses.sh with no further editing. Change-Id: Ie96faea295fe001911d77dbc51e9a6789558fbd6 Signed-off-by: Patrick Georgi <pgeorgi@chromium.org> Reviewed-on: http://review.coreboot.org/11888 Tested-by: build bot (Jenkins) Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com> Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
59 lines
1.6 KiB
C
59 lines
1.6 KiB
C
/*
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* This file is part of the coreboot project.
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*
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* Copyright (C) 2013 Google, Inc.
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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 <stdint.h>
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#include <cpu/x86/msr.h>
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#include <timer.h>
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#define MSR_COUNTER_24_MHz 0x637
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static struct monotonic_counter {
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int initialized;
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struct mono_time time;
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uint32_t last_value;
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} mono_counter;
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static inline uint32_t read_counter_msr(void)
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{
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/* Even though the MSR is 64-bit it is assumed that the hardware
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* is polled frequently enough to only use the lower 32-bits. */
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msr_t counter_msr;
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counter_msr = rdmsr(MSR_COUNTER_24_MHz);
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return counter_msr.lo;
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}
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void timer_monotonic_get(struct mono_time *mt)
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{
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uint32_t current_tick;
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uint32_t usecs_elapsed;
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if (!mono_counter.initialized) {
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mono_counter.last_value = read_counter_msr();
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mono_counter.initialized = 1;
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}
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current_tick = read_counter_msr();
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usecs_elapsed = (current_tick - mono_counter.last_value) / 24;
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/* Update current time and tick values only if a full tick occurred. */
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if (usecs_elapsed) {
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mono_time_add_usecs(&mono_counter.time, usecs_elapsed);
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mono_counter.last_value = current_tick;
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}
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/* Save result. */
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*mt = mono_counter.time;
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}
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