[PATCH v4 1/4] driver/perf: Add identifier sysfs file for Yitian 710 DDR

[Jing Zhang]

To allow userspace to identify the specific implementation of the device,
add an "identifier" sysfs file.

The perf tool can match the Yitian 710 DDR metric through the identifier.

Signed-off-by: Jing Zhang <renyu.zj at linux.alibaba.com>
Acked-by: Ian Rogers <irogers at google.com>
Reviewed-by: Shuai Xue <xueshuai at linux.alibaba.com>
---
 drivers/perf/alibaba_uncore_drw_pmu.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/perf/alibaba_uncore_drw_pmu.c b/drivers/perf/alibaba_uncore_drw_pmu.c
index a7689fe..fe075fd 100644
--- a/drivers/perf/alibaba_uncore_drw_pmu.c
+++ b/drivers/perf/alibaba_uncore_drw_pmu.c
@@ -236,10 +236,37 @@ static ssize_t ali_drw_pmu_cpumask_show(struct device *dev,
 	.attrs = ali_drw_pmu_cpumask_attrs,
 };
 
+static ssize_t ali_drw_pmu_identifier_show(struct device *dev,
+					struct device_attribute *attr,
+					char *page)
+{
+	return sysfs_emit(page, "%s\n", "ali_drw_pmu");
+}
+
+static umode_t ali_drw_pmu_identifier_attr_visible(struct kobject *kobj,
+						struct attribute *attr, int n)
+{
+	return attr->mode;
+}
+
+static struct device_attribute ali_drw_pmu_identifier_attr =
+	__ATTR(identifier, 0444, ali_drw_pmu_identifier_show, NULL);
+
+static struct attribute *ali_drw_pmu_identifier_attrs[] = {
+	&ali_drw_pmu_identifier_attr.attr,
+	NULL
+};
+
+static const struct attribute_group ali_drw_pmu_identifier_attr_group = {
+	.attrs = ali_drw_pmu_identifier_attrs,
+	.is_visible = ali_drw_pmu_identifier_attr_visible
+};
+
 static const struct attribute_group *ali_drw_pmu_attr_groups[] = {
 	&ali_drw_pmu_events_attr_group,
 	&ali_drw_pmu_cpumask_attr_group,
 	&ali_drw_pmu_format_group,
+	&ali_drw_pmu_identifier_attr_group,
 	NULL,
 };
 
-- 
1.8.3.1