linux-kernel - [PATCH v2 13/28] coresight: Set per CPU source pointer

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Message-Id: <20250701-arm_cs_pm_fix_v3-v2-13-23ebb864fcc1@arm.com>
Date: Tue, 01 Jul 2025 15:53:38 +0100
From: Leo Yan <leo.yan@....com>
To: Suzuki K Poulose <suzuki.poulose@....com>, 
 Mike Leach <mike.leach@...aro.org>, James Clark <james.clark@...aro.org>, 
 Levi Yun <yeoreum.yun@....com>, 
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
 Alexander Shishkin <alexander.shishkin@...ux.intel.com>, 
 Yabin Cui <yabinc@...gle.com>, Keita Morisaki <keyz@...gle.com>, 
 Yuanfang Zhang <quic_yuanfang@...cinc.com>
Cc: coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org, 
 linux-kernel@...r.kernel.org, Leo Yan <leo.yan@....com>
Subject: [PATCH v2 13/28] coresight: Set per CPU source pointer

Introduce coresight_set_percpu_source() for setting CPU source device. The
sources are maintained in a per CPU structure 'csdev_source'.

Signed-off-by: Leo Yan <leo.yan@....com>
---
 drivers/hwtracing/coresight/coresight-core.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 1a4bde5d6cd8fcfdd43bcafb45aa4dc5f1dd2d34..042e8e646ff521a15dc18d7264faa427f1ac0dc7 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -32,6 +32,7 @@
  */
 DEFINE_MUTEX(coresight_mutex);
 static DEFINE_PER_CPU(struct coresight_device *, csdev_sink);
+static DEFINE_PER_CPU(struct coresight_device *, csdev_source);
 
 /**
  * struct coresight_node - elements of a path, from source to sink
@@ -77,6 +78,11 @@ struct coresight_device *coresight_get_percpu_sink(int cpu)
 }
 EXPORT_SYMBOL_GPL(coresight_get_percpu_sink);
 
+static void coresight_set_percpu_source(int cpu, struct coresight_device *csdev)
+{
+	per_cpu(csdev_source, cpu) = csdev;
+}
+
 static struct coresight_device *coresight_get_source(struct coresight_path *path)
 {
 	struct coresight_device *csdev;
@@ -1390,6 +1396,10 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
 			goto out_unlock;
 		}
 	}
+
+	if (coresight_is_percpu_source(csdev))
+		coresight_set_percpu_source(csdev->cpu, csdev);
+
 	/* Device is now registered */
 	registered = true;
 
@@ -1421,6 +1431,8 @@ EXPORT_SYMBOL_GPL(coresight_register);
 
 void coresight_unregister(struct coresight_device *csdev)
 {
+	if (coresight_is_percpu_source(csdev))
+		coresight_set_percpu_source(csdev->cpu, NULL);
 	etm_perf_del_symlink_sink(csdev);
 	/* Remove references of that device in the topology */
 	if (cti_assoc_ops && cti_assoc_ops->remove)

-- 
2.34.1