libpayload: Add a timer_us() function.
This function returns the number of microseconds scaled from the number of raw timer ticks. It accepts a base parameter which is subtracted from the current time, which makes it easy to keep track of relative times. Change-Id: I55f2f9e90c0e12cda430bbe88b044f12b0b563c8 Signed-off-by: Gabe Black <gabeblack@google.com> Reviewed-on: https://chromium-review.googlesource.com/179600 Reviewed-by: Ronald Minnich <rminnich@chromium.org> Commit-Queue: Gabe Black <gabeblack@chromium.org> Tested-by: Gabe Black <gabeblack@chromium.org> (cherry picked from commit 4dd549e18d170dbf918c5b4b11bbe1f4e99b6695) Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com> Reviewed-on: http://review.coreboot.org/6897 Tested-by: build bot (Jenkins) Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
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@ -423,6 +423,7 @@ int lib_get_sysinfo(void);
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unsigned int get_cpu_speed(void);
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uint64_t timer_hz(void);
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uint64_t timer_raw_value(void);
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uint64_t timer_us(uint64_t base);
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/* Generic. */
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void ndelay(unsigned int n);
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void udelay(unsigned int n);
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@ -189,3 +189,20 @@ void delay(unsigned int s)
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{
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_delay((uint64_t)s * timer_hz());
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}
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u64 timer_us(u64 base)
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{
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static u64 hz;
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// Only check timer_hz once. Assume it doesn't change.
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if (hz == 0) {
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hz = timer_hz();
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if (hz < 1000000) {
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printf("Timer frequency %lld is too low, "
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"must be at least 1MHz.\n", hz);
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halt();
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}
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}
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return timer_raw_value() / (hz / 1000000) - base;
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}
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