linux-kernel - [PATCH v5 8/9] coresight: tmc: integrate byte-cntr's read_ops with sysfs file

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Message-Id: <20250812083731.549-9-jie.gan@oss.qualcomm.com>
Date: Tue, 12 Aug 2025 16:37:30 +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>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Yuanfang Zhang <quic_yuanfang@...cinc.com>,
        Mao Jinlong <quic_jinlmao@...cinc.com>,
        Jie Gan <quic_jiegan@...cinc.com>,
        Tingwei Zhang <tingwei.zhang@....qualcomm.com>
Cc: coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: [PATCH v5 8/9] coresight: tmc: integrate byte-cntr's read_ops with sysfs file_ops

Add code logic to invoke byte-cntr's sysfs_read_ops if the byte-cntr
is enabled.

Signed-off-by: Jie Gan <jie.gan@....qualcomm.com>
---
 .../hwtracing/coresight/coresight-tmc-core.c  | 53 ++++++++++++++++++-
 1 file changed, 52 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
index 23c8e903a474..ff68b3edb7cf 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-core.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
@@ -31,6 +31,7 @@
 
 #include "coresight-priv.h"
 #include "coresight-tmc.h"
+#include "coresight-ctcu.h"
 
 DEFINE_CORESIGHT_DEVLIST(etb_devs, "tmc_etb");
 DEFINE_CORESIGHT_DEVLIST(etf_devs, "tmc_etf");
@@ -228,15 +229,47 @@ static int tmc_prepare_crashdata(struct tmc_drvdata *drvdata)
 	return 0;
 }
 
+/* Return the byte-cntr's sysfs_read_ops if in use */
+static const struct sysfs_read_ops *tmc_qcom_byte_cntr_in_use(struct tmc_drvdata *drvdata)
+{
+	struct ctcu_byte_cntr *byte_cntr_data;
+	struct ctcu_drvdata *ctcu_drvdata;
+	struct coresight_device *helper;
+	int port;
+
+	helper = coresight_get_helper(drvdata->csdev, CORESIGHT_DEV_SUBTYPE_HELPER_CTCU);
+	if (!helper)
+		return NULL;
+
+	port = coresight_get_in_port_dest(drvdata->csdev, helper);
+	if (port < 0)
+		return NULL;
+
+	ctcu_drvdata = dev_get_drvdata(helper->dev.parent);
+	byte_cntr_data = &ctcu_drvdata->byte_cntr_data[port];
+	if (byte_cntr_data && byte_cntr_data->thresh_val)
+		return ctcu_drvdata->byte_cntr_sysfs_read_ops;
+
+	return NULL;
+}
+
 static int tmc_read_prepare(struct tmc_drvdata *drvdata)
 {
+	const struct sysfs_read_ops *byte_cntr_sysfs_read_ops;
 	int ret = 0;
 
+	byte_cntr_sysfs_read_ops = tmc_qcom_byte_cntr_in_use(drvdata);
+	if (byte_cntr_sysfs_read_ops) {
+		ret = byte_cntr_sysfs_read_ops->read_prepare(drvdata);
+		goto out;
+	}
+
 	if (drvdata->read_ops)
 		ret = drvdata->read_ops->read_prepare(drvdata);
 	else
 		ret = -EINVAL;
 
+out:
 	if (!ret)
 		dev_dbg(&drvdata->csdev->dev, "TMC read start\n");
 
@@ -245,13 +278,21 @@ static int tmc_read_prepare(struct tmc_drvdata *drvdata)
 
 static int tmc_read_unprepare(struct tmc_drvdata *drvdata)
 {
+	const struct sysfs_read_ops *byte_cntr_sysfs_read_ops;
 	int ret = 0;
 
+	byte_cntr_sysfs_read_ops = tmc_qcom_byte_cntr_in_use(drvdata);
+	if (byte_cntr_sysfs_read_ops) {
+		ret = byte_cntr_sysfs_read_ops->read_unprepare(drvdata);
+		goto out;
+	}
+
 	if (drvdata->read_ops)
 		ret = drvdata->read_ops->read_unprepare(drvdata);
 	else
 		ret = -EINVAL;
 
+out:
 	if (!ret)
 		dev_dbg(&drvdata->csdev->dev, "TMC read end\n");
 
@@ -277,6 +318,12 @@ static int tmc_open(struct inode *inode, struct file *file)
 static ssize_t tmc_get_sysfs_trace(struct tmc_drvdata *drvdata, loff_t pos, size_t len,
 				   char **bufpp)
 {
+	const struct sysfs_read_ops *byte_cntr_sysfs_read_ops;
+
+	byte_cntr_sysfs_read_ops = tmc_qcom_byte_cntr_in_use(drvdata);
+	if (byte_cntr_sysfs_read_ops)
+		return byte_cntr_sysfs_read_ops->get_trace_data(drvdata, pos, len, bufpp);
+
 	if (drvdata->read_ops)
 		return drvdata->read_ops->get_trace_data(drvdata, pos, len, bufpp);
 
@@ -300,7 +347,11 @@ static ssize_t tmc_read(struct file *file, char __user *data, size_t len,
 		return -EFAULT;
 	}
 
-	*ppos += actual;
+	if (drvdata->reading_node)
+		drvdata->reading_node->pos += actual;
+	else
+		*ppos += actual;
+
 	dev_dbg(&drvdata->csdev->dev, "%zu bytes copied\n", actual);
 
 	return actual;
-- 
2.34.1