From 4dd549e18d170dbf918c5b4b11bbe1f4e99b6695 Mon Sep 17 00:00:00 2001 From: Gabe Black Date: Fri, 6 Dec 2013 23:30:10 -0800 Subject: [PATCH] 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. BUG=None TEST=With a corresponding change in depthcharge, built and booted on link. BRANCH=None Change-Id: I55f2f9e90c0e12cda430bbe88b044f12b0b563c8 Signed-off-by: Gabe Black Reviewed-on: https://chromium-review.googlesource.com/179600 Reviewed-by: Ronald Minnich Commit-Queue: Gabe Black Tested-by: Gabe Black --- payloads/libpayload/include/libpayload.h | 1 + payloads/libpayload/libc/time.c | 17 +++++++++++++++++ 2 files changed, 18 insertions(+) diff --git a/payloads/libpayload/include/libpayload.h b/payloads/libpayload/include/libpayload.h index c63d91b1bc..d8aa243dcf 100644 --- a/payloads/libpayload/include/libpayload.h +++ b/payloads/libpayload/include/libpayload.h @@ -416,6 +416,7 @@ int lib_get_sysinfo(void); unsigned int get_cpu_speed(void); uint64_t timer_hz(void); uint64_t timer_raw_value(void); +uint64_t timer_us(uint64_t base); /* Generic. */ void ndelay(unsigned int n); void udelay(unsigned int n); diff --git a/payloads/libpayload/libc/time.c b/payloads/libpayload/libc/time.c index ec1c85ce8c..0d8163495b 100644 --- a/payloads/libpayload/libc/time.c +++ b/payloads/libpayload/libc/time.c @@ -189,3 +189,20 @@ void delay(unsigned int s) { _delay((uint64_t)s * timer_hz()); } + +u64 timer_us(u64 base) +{ + static u64 hz; + + // Only check timer_hz once. Assume it doesn't change. + if (hz == 0) { + hz = timer_hz(); + if (hz < 1000000) { + printf("Timer frequency %lld is too low, " + "must be at least 1MHz.\n", hz); + halt(); + } + } + + return timer_raw_value() / (hz / 1000000) - base; +}