[PATCH v4 11/11] coresight-tpdm: Add nodes for dsb msr support

[Tao Zhang]

Add the nodes for DSB subunit MSR(mux select register) support.
The TPDM MSR (mux select register) interface is an optional
interface and associated bank of registers per TPDM subunit.
The intent of mux select registers is to control muxing structures
driving the TPDM’s’ various subunit interfaces.

Signed-off-by: Tao Zhang <quic_taozha@xxxxxxxxxxx>
---
 .../ABI/testing/sysfs-bus-coresight-devices-tpdm   | 15 ++++++
 drivers/hwtracing/coresight/coresight-tpdm.c       | 53 ++++++++++++++++++++++
 drivers/hwtracing/coresight/coresight-tpdm.h       |  3 ++
 3 files changed, 71 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
index 639b6fb8..f746f25 100644
--- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
+++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-tpdm
@@ -170,3 +170,18 @@ Description:
 		Accepts only one of the 2 values -  0 or 1.
 		0 : Set the DSB pattern type to value.
 		1 : Set the DSB pattern type to toggle.
+
+What:		/sys/bus/coresight/devices/<tpdm-name>/dsb_msr
+Date:		March 2023
+KernelVersion	6.3
+Contact:	Jinlong Mao (QUIC) <quic_jinlmao@xxxxxxxxxxx>, Tao Zhang (QUIC) <quic_taozha@xxxxxxxxxxx>
+Description:
+		(Write) Set the MSR(mux select register) of DSB tpdm. Read
+		the MSR(mux select register) of DSB tpdm.
+
+		Expected format is the following:
+		<integer1> <integer2>
+
+		Where:
+		<integer1> : Index number of MSR register
+		<integer2> : The value need to be written
diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c b/drivers/hwtracing/coresight/coresight-tpdm.c
index 627de36..5fe0bd5c 100644
--- a/drivers/hwtracing/coresight/coresight-tpdm.c
+++ b/drivers/hwtracing/coresight/coresight-tpdm.c
@@ -240,6 +240,14 @@ static int tpdm_datasets_setup(struct tpdm_drvdata *drvdata)
 			if (!drvdata->dsb)
 				return -ENOMEM;
 		}
+		if (!of_property_read_u32(drvdata->dev->of_node,
+			   "qcom,dsb_msr_num", &drvdata->dsb->msr_num)) {
+			drvdata->dsb->msr = devm_kzalloc(drvdata->dev,
+				   (drvdata->dsb->msr_num * sizeof(*drvdata->dsb->msr)),
+				   GFP_KERNEL);
+			if (!drvdata->dsb->msr)
+				return -ENOMEM;
+		}
 	}
 
 	return 0;
@@ -765,6 +773,50 @@ static ssize_t dsb_trig_ts_store(struct device *dev,
 }
 static DEVICE_ATTR_RW(dsb_trig_ts);
 
+static ssize_t dsb_msr_show(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	unsigned int i;
+	ssize_t size = 0;
+
+	if (drvdata->dsb->msr_num == 0)
+		return -EINVAL;
+
+	spin_lock(&drvdata->spinlock);
+	for (i = 0; i < TPDM_DSB_MAX_PATT; i++) {
+		size += sysfs_emit_at(buf, size,
+				  "%u 0x%x\n", i, drvdata->dsb->msr[i]);
+	}
+	spin_unlock(&drvdata->spinlock);
+
+	return size;
+}
+
+static ssize_t dsb_msr_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf,
+				  size_t size)
+{
+	struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
+	unsigned int num, val;
+	int nval;
+
+	if (drvdata->dsb->msr_num == 0)
+		return -EINVAL;
+
+	nval = sscanf(buf, "%u %x", &num, &val);
+	if ((nval != 2) || (num >= (drvdata->dsb->msr_num - 1)))
+		return -EINVAL;
+
+	spin_lock(&drvdata->spinlock);
+	drvdata->dsb->msr[num] = val;
+	spin_unlock(&drvdata->spinlock);
+	return size;
+}
+static DEVICE_ATTR_RW(dsb_msr);
+
 static struct attribute *tpdm_dsb_attrs[] = {
 	&dev_attr_dsb_mode.attr,
 	&dev_attr_dsb_edge_ctrl.attr,
@@ -777,6 +829,7 @@ static struct attribute *tpdm_dsb_attrs[] = {
 	&dev_attr_dsb_trig_patt_mask.attr,
 	&dev_attr_dsb_trig_ts.attr,
 	&dev_attr_dsb_trig_type.attr,
+	&dev_attr_dsb_msr.attr,
 	NULL,
 };
 
diff --git a/drivers/hwtracing/coresight/coresight-tpdm.h b/drivers/hwtracing/coresight/coresight-tpdm.h
index 9ad32a6..05e9f8e 100644
--- a/drivers/hwtracing/coresight/coresight-tpdm.h
+++ b/drivers/hwtracing/coresight/coresight-tpdm.h
@@ -18,6 +18,7 @@
 #define TPDM_DSB_XPMR(n)	(0x7E8 + (n * 4))
 #define TPDM_DSB_EDCR(n)	(0x808 + (n * 4))
 #define TPDM_DSB_EDCMR(n)	(0x848 + (n * 4))
+#define TPDM_DSB_MSR(n)		(0x980 + (n * 4))
 
 /* Enable bit for DSB subunit */
 #define TPDM_DSB_CR_ENA		BIT(0)
@@ -113,6 +114,8 @@ struct dsb_dataset {
 	u32				trig_patt_mask[TPDM_DSB_MAX_PATT];
 	bool			trig_ts;
 	bool			trig_type;
+	u32				msr_num;
+	u32				*msr;
 };
 
 /**
-- 
2.7.4