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From:   Jing Zhang <renyu.zj@linux.alibaba.com>
To:     John Garry <john.g.garry@oracle.com>,
        Ian Rogers <irogers@google.com>, Will Deacon <will@kernel.org>,
        James Clark <james.clark@arm.com>,
        Mike Leach <mike.leach@linaro.org>,
        Leo Yan <leo.yan@linaro.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Adrian Hunter <adrian.hunter@intel.com>
Cc:     linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-perf-users@vger.kernel.org,
        Shuai Xue <xueshuai@linux.alibaba.com>,
        Zhuo Song <zhuo.song@linux.alibaba.com>,
        Jing Zhang <renyu.zj@linux.alibaba.com>
Subject: [PATCH RFC 1/4] driver/perf: Add identifier sysfs file for CMN
Date:   Mon, 27 Mar 2023 10:46:09 +0800
Message-Id: <1679885172-95021-2-git-send-email-renyu.zj@linux.alibaba.com>
In-Reply-To: <1679885172-95021-1-git-send-email-renyu.zj@linux.alibaba.com>
References: <1679885172-95021-1-git-send-email-renyu.zj@linux.alibaba.com>
Precedence: bulk

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

The perf tool can match the arm CMN metric through the identifier.

Signed-off-by: Jing Zhang <renyu.zj@linux.alibaba.com>
---
 drivers/perf/arm-cmn.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
index c968986..0c138ad 100644
--- a/drivers/perf/arm-cmn.c
+++ b/drivers/perf/arm-cmn.c
@@ -1168,10 +1168,53 @@ static ssize_t arm_cmn_cpumask_show(struct device *dev,
 	.attrs = arm_cmn_cpumask_attrs,
 };
 
+static ssize_t arm_cmn_identifier_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct arm_cmn *cmn = to_cmn(dev_get_drvdata(dev));
+	if (cmn->model == CMN700) {
+		return sysfs_emit(buf, "%s\n", "CMN700");
+	}
+	else if (cmn->model == CMN650) {
+		return sysfs_emit(buf, "%s\n", "CMN650");
+	}
+	else if (cmn->model == CMN600) {
+		return sysfs_emit(buf, "%s\n", "CMN600");
+	}
+	else if (cmn->model == CI700) {
+		return sysfs_emit(buf, "%s\n", "CI700");
+	}
+	return sysfs_emit(buf, "%s\n", "UNKNOWN");
+}
+
+static umode_t arm_cmn_identifier_attr_visible(struct kobject *kobj,
+		struct attribute *attr, int n)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct arm_cmn *cmn = to_cmn(dev_get_drvdata(dev));
+	if (cmn->model <= 0)
+		return 0;
+	return attr->mode;
+};
+
+static struct device_attribute arm_cmn_identifier_attr =
+__ATTR(identifier, 0444, arm_cmn_identifier_show, NULL);
+
+static struct attribute *arm_cmn_identifier_attrs[] = {
+	&arm_cmn_identifier_attr.attr,
+	NULL,
+};
+
+static struct attribute_group arm_cmn_identifier_attr_group = {
+	.attrs = arm_cmn_identifier_attrs,
+	.is_visible = arm_cmn_identifier_attr_visible,
+};
+
 static const struct attribute_group *arm_cmn_attr_groups[] = {
 	&arm_cmn_event_attrs_group,
 	&arm_cmn_format_attrs_group,
 	&arm_cmn_cpumask_attr_group,
+	&arm_cmn_identifier_attr_group,
 	NULL
 };
 
-- 
1.8.3.1