linux-kernel - [PATCH v2 2/8] coresight: Convert tag clear function to take a struct cs

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Message-Id: <20250318-james-coresight-claim-tags-v2-2-e9c8a9cde84e@linaro.org>
Date: Tue, 18 Mar 2025 16:21:56 +0000
From: James Clark <james.clark@...aro.org>
To: Suzuki K Poulose <suzuki.poulose@....com>, 
 Mike Leach <mike.leach@...aro.org>, James Clark <james.clark@...aro.org>, 
 Alexander Shishkin <alexander.shishkin@...ux.intel.com>, 
 Maxime Coquelin <mcoquelin.stm32@...il.com>, 
 Alexandre Torgue <alexandre.torgue@...s.st.com>, Suzuki.Poulose@....com, 
 leo.yan@....com
Cc: coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org, 
 linux-kernel@...r.kernel.org, linux-stm32@...md-mailman.stormreply.com
Subject: [PATCH v2 2/8] coresight: Convert tag clear function to take a
 struct cs_access

The self hosted claim tag will be reset on device probe in a later
commit. We'll want to do this before coresight_register() is called so
won't have a coresight_device and have to use cs_access instead.

Also make them public and create locked and unlocked versions for
later use.

Signed-off-by: James Clark <james.clark@...aro.org>
---
 drivers/hwtracing/coresight/coresight-core.c | 17 +++++++++++++----
 include/linux/coresight.h                    |  3 ++-
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 3f1c996d668a..9ff601e2415a 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -151,12 +151,21 @@ static inline void coresight_set_self_claim_tag(struct coresight_device *csdev)
 	isb();
 }
 
-static inline void coresight_clear_self_claim_tag(struct coresight_device *csdev)
+void coresight_clear_self_claim_tag(struct csdev_access *csa)
 {
-	csdev_access_relaxed_write32(&csdev->access, CORESIGHT_CLAIM_SELF_HOSTED,
+	CS_UNLOCK(csa->base);
+	coresight_clear_self_claim_tag_unlocked(csa);
+	CS_LOCK(csa->base);
+}
+EXPORT_SYMBOL_GPL(coresight_clear_self_claim_tag);
+
+void coresight_clear_self_claim_tag_unlocked(struct csdev_access *csa)
+{
+	csdev_access_relaxed_write32(csa, CORESIGHT_CLAIM_SELF_HOSTED,
 				     CORESIGHT_CLAIMCLR);
 	isb();
 }
+EXPORT_SYMBOL_GPL(coresight_clear_self_claim_tag_unlocked);
 
 /*
  * coresight_claim_device_unlocked : Claim the device for self-hosted usage
@@ -180,7 +189,7 @@ int coresight_claim_device_unlocked(struct coresight_device *csdev)
 	if (coresight_is_claimed_self_hosted(csdev))
 		return 0;
 	/* There was a race setting the tag, clean up and fail */
-	coresight_clear_self_claim_tag(csdev);
+	coresight_clear_self_claim_tag_unlocked(&csdev->access);
 	return -EBUSY;
 }
 EXPORT_SYMBOL_GPL(coresight_claim_device_unlocked);
@@ -211,7 +220,7 @@ void coresight_disclaim_device_unlocked(struct coresight_device *csdev)
 		return;
 
 	if (coresight_is_claimed_self_hosted(csdev))
-		coresight_clear_self_claim_tag(csdev);
+		coresight_clear_self_claim_tag_unlocked(&csdev->access);
 	else
 		/*
 		 * The external agent may have not honoured our claim
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index d79a242b271d..00134a80d358 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -685,7 +685,8 @@ extern int coresight_timeout_action(struct csdev_access *csa, u32 offset,
 
 extern int coresight_claim_device(struct coresight_device *csdev);
 extern int coresight_claim_device_unlocked(struct coresight_device *csdev);
-
+void coresight_clear_self_claim_tag(struct csdev_access *csa);
+void coresight_clear_self_claim_tag_unlocked(struct csdev_access *csa);
 extern void coresight_disclaim_device(struct coresight_device *csdev);
 extern void coresight_disclaim_device_unlocked(struct coresight_device *csdev);
 extern char *coresight_alloc_device_name(struct coresight_dev_list *devs,

-- 
2.34.1