On Tue, Feb 11, 2025 at 10:39:40AM +0000, James Clark wrote:
Add a dev_dbg() message so that external debugger conflicts are more visible. There are multiple reasons for -EBUSY so a message for this particular one could be helpful. Add errors for and enumerate all the other cases that are impossible.
Signed-off-by: James Clark james.clark@linaro.org
drivers/hwtracing/coresight/coresight-core.c | 48 ++++++++++++-------- drivers/hwtracing/coresight/coresight-priv.h | 5 +- 2 files changed, 34 insertions(+), 19 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c index 7b53165c93af..7fe5d5d432c4 100644 --- a/drivers/hwtracing/coresight/coresight-core.c +++ b/drivers/hwtracing/coresight/coresight-core.c @@ -133,16 +133,6 @@ static inline u32 coresight_read_claim_tags(struct csdev_access *csa) csdev_access_relaxed_read32(csa, CORESIGHT_CLAIMCLR)); }
-static inline bool coresight_is_claimed_self_hosted(struct csdev_access *csa) -{
return coresight_read_claim_tags(csa) == CORESIGHT_CLAIM_SELF_HOSTED;-}
-static inline bool coresight_is_claimed_any(struct coresight_device *csdev) -{
return coresight_read_claim_tags(&csdev->access) != 0;-}
static inline void coresight_set_self_claim_tag(struct csdev_access *csa) { csdev_access_relaxed_write32(csa, CORESIGHT_CLAIM_SELF_HOSTED, @@ -169,18 +159,40 @@ static inline void coresight_clear_self_claim_tag(struct csdev_access *csa) */ int coresight_claim_device_unlocked(struct coresight_device *csdev) {
int tag;struct csdev_access *csa;if (WARN_ON(!csdev)) return -EINVAL;
if (coresight_is_claimed_any(csdev))
csa = &csdev->access;tag = coresight_read_claim_tags(csa);switch (tag) {case CORESIGHT_CLAIM_FREE:coresight_set_self_claim_tag(csa);if (coresight_read_claim_tags(csa) == CORESIGHT_CLAIM_SELF_HOSTED)return 0;
It would be a rare case if a failure happens here. Seems to me, it would be valuable to print a log for this edge case.
Otherwise, looks good to me.
/* There was a race setting the tag, clean up and fail */coresight_clear_self_claim_tag(csa); return -EBUSY;
coresight_set_self_claim_tag(&csdev->access);if (coresight_is_claimed_self_hosted(&csdev->access))return 0;/* There was a race setting the tag, clean up and fail */coresight_clear_self_claim_tag(&csdev->access);return -EBUSY;
case CORESIGHT_CLAIM_EXTERNAL:/* External debug is an expected state, so log and report BUSY */dev_dbg(&csdev->dev, "Busy: Claimed by external debugger");return -EBUSY;default:case CORESIGHT_CLAIM_SELF_HOSTED:case CORESIGHT_CLAIM_INVALID:/** Warn here because we clear a lingering self hosted tag* on probe, so other tag combinations are impossible.*/dev_err_once(&csdev->dev, "Invalid claim tag state: %x", tag);return -EBUSY;}} EXPORT_SYMBOL_GPL(coresight_claim_device_unlocked);
@@ -205,7 +217,7 @@ EXPORT_SYMBOL_GPL(coresight_claim_device); */ void coresight_disclaim_device_unlocked(struct csdev_access *csa) {
if (coresight_is_claimed_self_hosted(csa))
if (coresight_read_claim_tags(csa) == CORESIGHT_CLAIM_SELF_HOSTED) coresight_clear_self_claim_tag(csa); else /*diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h index cc7ff1e36ef4..a83113225797 100644 --- a/drivers/hwtracing/coresight/coresight-priv.h +++ b/drivers/hwtracing/coresight/coresight-priv.h @@ -36,7 +36,10 @@ extern const struct device_type coresight_dev_type[];
- See PSCI - ARM DEN 0022D, Section: 6.8.1 Debug and Trace save and restore.
*/ #define CORESIGHT_CLAIM_MASK GENMASK(1, 0) -#define CORESIGHT_CLAIM_SELF_HOSTED BIT(1) +#define CORESIGHT_CLAIM_FREE 0 +#define CORESIGHT_CLAIM_EXTERNAL 1 +#define CORESIGHT_CLAIM_SELF_HOSTED 2 +#define CORESIGHT_CLAIM_INVALID 3
#define TIMEOUT_US 100
#define BMVAL(val, lsb, msb) ((val & GENMASK(msb, lsb)) >> lsb)
2.34.1
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