[PATCH v1 3/3] coresight: tpda: add sysfs node to flush specific port

[Jie Gan]

From: Tao Zhang <tao.zhang at oss.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 at oss.qualcomm.com>
Co-developed-by: Jie Gan <jie.gan at oss.qualcomm.com>
Signed-off-by: Jie Gan <jie.gan at oss.qualcomm.com>
---
 .../testing/sysfs-bus-coresight-devices-tpda  |  7 +++
 drivers/hwtracing/coresight/coresight-tpda.c  | 45 +++++++++++++++++++
 drivers/hwtracing/coresight/coresight-tpda.h  |  1 +
 3 files changed, 53 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpda b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpda
index e827396a0fa1..8803158ba42f 100644
--- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpda
+++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpda
@@ -41,3 +41,10 @@ Contact:	Jinlong Mao <jinlong.mao at oss.qualcomm.com>, Tao Zhang <tao.zhang at oss.qu
 Description:
 		(RW) Configure the CMB/MCMB channel mode for all enabled ports.
 		Value 0 means raw channel mapping mode. Value 1 means channel pair marking mode.
+
+What:		/sys/bus/coresight/devices/<tpda-name>/port_flush_req
+Date:		August 2025
+KernelVersion:	6.17
+Contact:	Jinlong Mao <jinlong.mao at oss.qualcomm.com>, Tao Zhang <tao.zhang at oss.qualcomm.com>, Jie Gan <jie.gan at oss.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 9e623732d1e7..c5f169facc51 100644
--- a/drivers/hwtracing/coresight/coresight-tpda.c
+++ b/drivers/hwtracing/coresight/coresight-tpda.c
@@ -509,6 +509,50 @@ static ssize_t cmbchan_mode_store(struct device *dev,
 }
 static DEVICE_ATTR_RW(cmbchan_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;
+
+	guard(spinlock)(&drvdata->spinlock);
+	if (!drvdata->csdev->refcnt)
+		return -EPERM;
+
+	val = readl_relaxed(drvdata->base + TPDA_FLUSH_CR);
+	return sysfs_emit(buf, "%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);
+	unsigned long val;
+
+	if (kstrtoul(buf, 0, &val))
+		return -EINVAL;
+
+	/* The valid value ranges from 0 to 127 */
+	if (val > 127)
+		return -EINVAL;
+
+	guard(spinlock)(&drvdata->spinlock);
+	if (!drvdata->csdev->refcnt)
+		return -EPERM;
+
+	if (val) {
+		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_trig_async_enable.attr,
 	&dev_attr_trig_flag_ts_enable.attr,
@@ -516,6 +560,7 @@ static struct attribute *tpda_attrs[] = {
 	&dev_attr_freq_ts_enable.attr,
 	&dev_attr_global_flush_req.attr,
 	&dev_attr_cmbchan_mode.attr,
+	&dev_attr_port_flush_req.attr,
 	NULL,
 };
 
diff --git a/drivers/hwtracing/coresight/coresight-tpda.h b/drivers/hwtracing/coresight/coresight-tpda.h
index 00d146960d81..55a18d718357 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 FREQ packets timestamp bit */
 #define TPDA_CR_FREQTS		BIT(2)
-- 
2.34.1