diff options
| author | Daisuke Nojiri <dnojiri@chromium.org> | 2021-10-11 12:50:25 -0700 |
|---|---|---|
| committer | Chromeos LUCI <chromeos-scoped@luci-project-accounts.iam.gserviceaccount.com> | 2022-03-28 18:17:32 +0000 |
| commit | 5822c27c9775e21410e98ab72c64eb4c1b198e84 (patch) | |
| tree | 504326d0830917b9a71af9f847a54b054b974d4e | |
| parent | b052c5d9ffebc48646a76922ed5711bf9a8d41dc (diff) | |
| download | chrome-ec-5822c27c9775e21410e98ab72c64eb4c1b198e84.tar.gz | |
npcx/timer: Unroll udelay
This patch flattens udelay by unrolling __hw_clock_source_read.
This increases the chance that we record LR of the instruction
near which an infinite loop happened.
BUG=b:218982018,b:200593658
BRANCH=
TEST=Sona. Run crash assert. Hack battery command to trigger WD reset.
Verify LR points to the root causes.
Change-Id: Ibd6cbcf18ab6d58c06ddfd19021058268289bf00
Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
(cherry picked from commit cc1d30dd2bd3b92d29f5ffb942d016bc207e2ad0)
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3508422
| -rw-r--r-- | chip/npcx/hwtimer.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/chip/npcx/hwtimer.c b/chip/npcx/hwtimer.c index 76f1822a94..75b026c939 100644 --- a/chip/npcx/hwtimer.c +++ b/chip/npcx/hwtimer.c @@ -16,6 +16,7 @@ #include "console.h" #include "task.h" #include "timer.h" +#include "registers.h" #include "util.h" /* Depth of event timer */ @@ -340,3 +341,23 @@ int __hw_clock_source_init(uint32_t start_t) return NPCX_IRQ_ITIM32; } + +/* + * Unrolled udelay. It preserves LR, which points to the root cause of WD crash. + */ +__override void udelay(unsigned us) +{ + uint32_t cnt, cnt2, t0; + + cnt = NPCX_ITCNT32; + while ((cnt2 = NPCX_ITCNT32) != cnt) + cnt = cnt2; + + t0 = TICK_ITIM32_MAX_CNT - cnt; + + do { + cnt = NPCX_ITCNT32; + while ((cnt2 = NPCX_ITCNT32) != cnt) + cnt = cnt2; + } while (TICK_ITIM32_MAX_CNT - cnt - t0 <= us); +} |