linux-kernel - [PATCH v6 4/4] coresight: tpda: add sysfs node to flush specific port

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Message-Id: <20251222-add_sysfs_nodes_to_configure_tpda-v6-4-b27143d45c86@oss.qualcomm.com>
Date: Mon, 22 Dec 2025 14:02:24 +0800
From: Jie Gan <jie.gan@....qualcomm.com>
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>,
        Tingwei Zhang <tingwei.zhang@....qualcomm.com>
Cc: coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, Jie Gan <jie.gan@....qualcomm.com>,
        Tao Zhang <tao.zhang@....qualcomm.com>
Subject: [PATCH v6 4/4] coresight: tpda: add sysfs node to flush specific
 port

From: Tao Zhang <tao.zhang@....qualcomm.com>

Setting bit i in the TPDA_FLUSH_CR register initiates a flush request
for port i, forcing the data to synchronize and be transmitted to the
sink device.

Signed-off-by: Tao Zhang <tao.zhang@....qualcomm.com>
Reviewed-by: James Clark <james.clark@...aro.org>
Co-developed-by: Jie Gan <jie.gan@....qualcomm.com>
Signed-off-by: Jie Gan <jie.gan@....qualcomm.com>
---
 .../ABI/testing/sysfs-bus-coresight-devices-tpda   |  7 ++++
 drivers/hwtracing/coresight/coresight-tpda.c       | 40 ++++++++++++++++++++++
 drivers/hwtracing/coresight/coresight-tpda.h       |  1 +
 3 files changed, 48 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpda b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpda
index d359d90dca72..df8f03d4b573 100644
--- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpda
+++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpda
@@ -51,3 +51,10 @@ Description:
 		mode 0 - COUNT[11:0] value represents the approximate number of bytes moved between two ASYNC packet requests
 		mode 1 - the bits COUNT[11:7] are used as a power of 2. for example, we could insert an async packet every 8K
 		         data by writing a value 13 to the COUNT[11:7] field.
+
+What:		/sys/bus/coresight/devices/<tpda-name>/port_flush_req
+Date:		December 2025
+KernelVersion:	6.19
+Contact:	Jinlong Mao <jinlong.mao@....qualcomm.com>, Tao Zhang <tao.zhang@....qualcomm.com>, Jie Gan <jie.gan@....qualcomm.com>
+Description:
+		(RW) Configure the bit i to requests a flush operation of port i on the TPDA.
diff --git a/drivers/hwtracing/coresight/coresight-tpda.c b/drivers/hwtracing/coresight/coresight-tpda.c
index 7baa8a0965d3..f79fea4fbb2c 100644
--- a/drivers/hwtracing/coresight/coresight-tpda.c
+++ b/drivers/hwtracing/coresight/coresight-tpda.c
@@ -430,9 +430,49 @@ static ssize_t syncr_mode_store(struct device *dev,
 }
 static DEVICE_ATTR_RW(syncr_mode);
 
+static ssize_t port_flush_req_show(struct device *dev,
+				   struct device_attribute *attr,
+				   char *buf)
+{
+	struct tpda_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	unsigned long val;
+
+	if (!drvdata->csdev->refcnt)
+		return -EINVAL;
+
+	guard(spinlock)(&drvdata->spinlock);
+	val = readl_relaxed(drvdata->base + TPDA_FLUSH_CR);
+
+	return sysfs_emit(buf, "0x%lx\n", val);
+}
+
+static ssize_t port_flush_req_store(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf,
+				    size_t size)
+{
+	struct tpda_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	u32 val;
+
+	if (kstrtou32(buf, 0, &val))
+		return -EINVAL;
+
+	if (!drvdata->csdev->refcnt || !val)
+		return -EINVAL;
+
+	guard(spinlock)(&drvdata->spinlock);
+	CS_UNLOCK(drvdata->base);
+	writel_relaxed(val, drvdata->base + TPDA_FLUSH_CR);
+	CS_LOCK(drvdata->base);
+
+	return size;
+}
+static DEVICE_ATTR_RW(port_flush_req);
+
 static struct attribute *tpda_attrs[] = {
 	&dev_attr_global_flush_req.attr,
 	&dev_attr_syncr_mode.attr,
+	&dev_attr_port_flush_req.attr,
 	tpda_trig_sysfs_rw(freq_ts_enable, FREQTS),
 	tpda_trig_sysfs_rw(trig_freq_enable, FRIE),
 	tpda_trig_sysfs_rw(trig_flag_ts_enable, FLRIE),
diff --git a/drivers/hwtracing/coresight/coresight-tpda.h b/drivers/hwtracing/coresight/coresight-tpda.h
index 1d2de50bb9f9..ef1ce2ce36a9 100644
--- a/drivers/hwtracing/coresight/coresight-tpda.h
+++ b/drivers/hwtracing/coresight/coresight-tpda.h
@@ -10,6 +10,7 @@
 #define TPDA_Pn_CR(n)		(0x004 + (n * 4))
 #define TPDA_FPID_CR		(0x084)
 #define TPDA_SYNCR		(0x08C)
+#define TPDA_FLUSH_CR		(0x090)
 
 /* Cross trigger global (all ports) flush request bit */
 #define TPDA_CR_FLREQ		BIT(0)

-- 
2.34.1