coresight-etm4x: Read only access to the tracer's ID registers

ETM ID registers contain valuable information about the capabilities
of the implementation and are very useful when configuring the device for
various trace scenarios.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/coresight/coresight-etm4x.c

@@ -2238,6 +2238,37 @@ static struct attribute *coresight_etmv4_mgmt_attrs[] = {
 	NULL,
 };
 
+coresight_simple_func(trcidr0, TRCIDR0);
+coresight_simple_func(trcidr1, TRCIDR1);
+coresight_simple_func(trcidr2, TRCIDR2);
+coresight_simple_func(trcidr3, TRCIDR3);
+coresight_simple_func(trcidr4, TRCIDR4);
+coresight_simple_func(trcidr5, TRCIDR5);
+/* trcidr[6,7] are reserved */
+coresight_simple_func(trcidr8, TRCIDR8);
+coresight_simple_func(trcidr9, TRCIDR9);
+coresight_simple_func(trcidr10, TRCIDR10);
+coresight_simple_func(trcidr11, TRCIDR11);
+coresight_simple_func(trcidr12, TRCIDR12);
+coresight_simple_func(trcidr13, TRCIDR13);
+
+static struct attribute *coresight_etmv4_trcidr_attrs[] = {
+	&dev_attr_trcidr0.attr,
+	&dev_attr_trcidr1.attr,
+	&dev_attr_trcidr2.attr,
+	&dev_attr_trcidr3.attr,
+	&dev_attr_trcidr4.attr,
+	&dev_attr_trcidr5.attr,
+	/* trcidr[6,7] are reserved */
+	&dev_attr_trcidr8.attr,
+	&dev_attr_trcidr9.attr,
+	&dev_attr_trcidr10.attr,
+	&dev_attr_trcidr11.attr,
+	&dev_attr_trcidr12.attr,
+	&dev_attr_trcidr13.attr,
+	NULL,
+};
+
 static const struct attribute_group coresight_etmv4_group = {
 	.attrs = coresight_etmv4_attrs,
 };
@@ -2247,9 +2278,15 @@ static const struct attribute_group coresight_etmv4_mgmt_group = {
 	.name = "mgmt",
 };
 
+static const struct attribute_group coresight_etmv4_trcidr_group = {
+	.attrs = coresight_etmv4_trcidr_attrs,
+	.name = "trcidr",
+};
+
 static const struct attribute_group *coresight_etmv4_groups[] = {
 	&coresight_etmv4_group,
 	&coresight_etmv4_mgmt_group,
+	&coresight_etmv4_trcidr_group,
 	NULL,
 };