Check for overflow in udelay/usleep_range use in __xe_mmio_wait32
and pick the correct helper according to the wait time and atomic.
Implement a similar helper to replace DIV_ROUND_UP for 32-bit CPUs.
Avoid growing delays becoming intollerably large by capping the
in-loop wait time.
v5: - Simplify: don't introduce additional redesign and
use min_t with a backoff to cap wait. (Rodrigo).
v4: - Simplify using poll_timeout_us and poll_timeout_us_atopmic and
update all callstack to never use a param for atomic (Jani)
v3: - Use div64_s64 kernel API for 32-bit vs 64-bit division.
v2: - Fixed checkpatch failure.
- Added helper for 64-bit DIV_ROUND_UP on 32-bit CPU (Shasiko
review). Fixed bug max range in usleep_range(Shasiko review)
Fixes: 5c09bd6ccd41 ("drm/xe/mmio: Move xe_mmio_wait32() to xe_mmio.c")
Signed-off-by: Alan Previn <[email protected]>
Assisted-by: Github-Copilot:Claude-Sonnet-5-0
---
drivers/gpu/drm/xe/xe_mmio.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_mmio.c b/drivers/gpu/drm/xe/xe_mmio.c
index 7fa18dfcb5a2..c7c37e59dab0 100644
--- a/drivers/gpu/drm/xe/xe_mmio.c
+++ b/drivers/gpu/drm/xe/xe_mmio.c
@@ -350,10 +350,11 @@ static int __xe_mmio_wait32(struct xe_mmio *mmio, struct
xe_reg reg, u32 mask, u
wait = ktime_us_delta(end, cur);
if (atomic)
- udelay(wait);
+ udelay(min_t(s64, wait, MAX_UDELAY_MS));
else
usleep_range(wait, wait << 1);
- wait <<= 1;
+#define __XE_MMIO_WAIT_MAX_BACKOFF_100MS (100 * USEC_PER_MSEC)
+ wait = min_t(s64, wait << 1, __XE_MMIO_WAIT_MAX_BACKOFF_100MS);
}
if (ret != 0) {
--
2.43.0
