libpayload: pistachio: fix timer implementation

timer_raw_value must return the number of CPU ticks, and not
the time obtained by dividing the ticks by the CPU frequency.
The CPU counter is increased at every 2 CPU clocks
and therfore the number of ticks will be the counter value
multiplied by 2.

BUG=chrome-os-partner:31438
TEST=tested on Pistachio FPGA; it works properly.
BRANCH=none

Change-Id: Iae62cb328e882f84822250bdf72146321ca9bbe0
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 7ab25ce7dcaffb453ee774d870963a56444d46af
Original-Change-Id: I74408950900463a2c054d5aebd3edb005a325adb
Original-Signed-off-by: Ionela Voinescu <ionela.voinescu@imgtec.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/242393
Original-Reviewed-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: http://review.coreboot.org/8744
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

1 files changed, 1 insertions, 6 deletions

diff --git a/payloads/libpayload/drivers/timer/img_pistachio.c b/payloads/libpayload/drivers/timer/img_pistachio.c
index dcfe555a73..ae53a9d0b1 100644
--- a/payloads/libpayload/drivers/timer/img_pistachio.c
+++ b/payloads/libpayload/drivers/timer/img_pistachio.c
@@ -20,11 +20,6 @@
 #include <libpayload.h>
 #include <arch/cpu.h>
 
-static int get_timer_speed_khz(void)
-{
-	return get_cpu_speed()/2;
-}
-
 uint64_t timer_hz(void)
 {
 	return lib_sysinfo.cpu_khz * 1000;
@@ -32,5 +27,5 @@ uint64_t timer_hz(void)
 
 uint64_t timer_raw_value(void)
 {
-	return read_c0_count()/(get_timer_speed_khz()/1000);
+	return read_c0_count() * 2;
 }