coresight: tpda: add sysfs node to flush specific port

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@oss.qualcomm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Co-developed-by: Jie Gan <jie.gan@oss.qualcomm.com>
Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
[ Fix kernel version in Documentation ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20251223-add_sysfs_nodes_to_configure_tpda-v8-4-4c95db608b62@oss.qualcomm.com

3 files changed, 49 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpda b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpda
index bd86e6fd961d..54f05964a360 100644
--- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpda
+++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpda
@@ -59,3 +59,11 @@ Contact:	Jinlong Mao <jinlong.mao@oss.qualcomm.com>, Tao Zhang <tao.zhang@oss.qu
 Description:
 		(RW) Set value the of the syncr counter.
 		Range: 0-4095
+
+What:		/sys/bus/coresight/devices/<tpda-name>/port_flush_req
+Date:		December 2025
+KernelVersion:	6.20
+Contact:	Jinlong Mao <jinlong.mao@oss.qualcomm.com>, Tao Zhang <tao.zhang@oss.qualcomm.com>, Jie Gan <jie.gan@oss.qualcomm.com>
+Description:
+		(RW) Configure the bit i to requests a flush operation of port i on the TPDA.
+		The requested bit(s) remain set until the flush request completes.
diff --git a/drivers/hwtracing/coresight/coresight-tpda.c b/drivers/hwtracing/coresight/coresight-tpda.c
index deb5a646a04c..7055f8f13427 100644
--- a/drivers/hwtracing/coresight/coresight-tpda.c
+++ b/drivers/hwtracing/coresight/coresight-tpda.c
@@ -473,10 +473,50 @@ static ssize_t syncr_count_store(struct device *dev,
 }
 static DEVICE_ATTR_RW(syncr_count);
 
+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_syncr_count.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 56d35697303a..a090352009bb 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)