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pistachio: modify timer to account for CPU counter overflow 

Extended the 32bit CPU counter to 64bit by adding a static
variable that takes into account CPU counter overflow.
The varibale is updated everythime the timer_raw_value
function is called so I assume that the function is called
often enought to not miss an overflow of the CPU counter.

BUG=chrome-os-partner:31438
TEST=tested on Pistachio bring up board; works as expected
BRANCH=none

Change-Id: I98bcc56e600dcff0c6da7c140dd34faec5e00885
Signed-off-by: Stefan Reinauer <reinauer@chromium.org>
Original-Commit-Id: 972b105f950d800fa44f27bce090f6b89a5a84b9
Original-Change-Id: Id67b14e9d9c2354bc417b6587b615d466690c9b7
Original-Signed-off-by: Ionela Voinescu <ionela.voinescu@imgtec.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/247642
Original-Reviewed-by: Daniel Ehrenberg <dehrenberg@chromium.org>
Reviewed-on: http://review.coreboot.org/9672
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
This commit is contained in:
Ionela Voinescu 2015-02-10 18:41:47 +00:00 committed by Patrick Georgi
parent 0f58d0b941
commit 7d16196a8e
1 changed files with 12 additions and 1 deletions
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13
payloads/libpayload/drivers/timer/img_pistachio.c
View File

@ -27,5 +27,16 @@ uint64_t timer_hz(void)
uint64_t timer_raw_value(void) uint64_t timer_raw_value(void)
{ {
return read_c0_count() * 2; static uint64_t total_ticks = 0;
uint8_t overflow = 0;
uint32_t current_ticks = read_c0_count() * 2;
/* It assumes only one overflow happened since the last call */
if (current_ticks <= (uint32_t)total_ticks)
overflow = 1;
/* The least significant part(32 bits) of total_ticks will always
* become equal to current ticks */
total_ticks = (((total_ticks >> 32) + overflow) << 32) +
current_ticks;
return total_ticks;
} }