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coresight: Only check bottom two claim bits

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The use of the whole register and == could break the claim mechanism if
any of the other bits are used in the future. The referenced doc "PSCI -
ARM DEN 0022D" also says to only read and clear the bottom two bits.

Use FIELD_GET() to extract only the relevant part.

Reviewed-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20250325-james-coresight-claim-tags-v4-2-dfbd3822b2e5@linaro.org
This commit is contained in:
James Clark 2025-03-25 11:58:47 +00:00 committed by Suzuki K Poulose
parent fc7fed6f77
commit a4e65842e1
2 changed files with 3 additions and 1 deletions
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3
drivers/hwtracing/coresight/coresight-core.c
View file

@ -131,7 +131,8 @@ coresight_find_out_connection(struct coresight_device *csdev,
static inline u32 coresight_read_claim_tags_unlocked(struct coresight_device *csdev)
{
return csdev_access_relaxed_read32(&csdev->access, CORESIGHT_CLAIMCLR);
return FIELD_GET(CORESIGHT_CLAIM_MASK,
csdev_access_relaxed_read32(&csdev->access, CORESIGHT_CLAIMCLR));
}
static inline bool coresight_is_claimed_self_hosted(struct coresight_device *csdev)

1
drivers/hwtracing/coresight/coresight-priv.h
View file

@ -35,6 +35,7 @@ extern const struct device_type coresight_dev_type[];
* Coresight device CLAIM protocol.
* 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 TIMEOUT_US 100