在 2023/3/27 下午3:55, John Garry 写道:
On 27/03/2023 03:46, Jing Zhang wrote:Will do.
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@xxxxxxxxxxxxxxxxx>
---
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");
Is it possible to have a pointer to this string in struct arm_cmn, such that we don't have to do this model to identifier lookup here? If-else chains like this are not scalable.
BTW, does this HW have some HW identifier register, like iidr? I think that using that may be preferable.
I didn't find the relevant identifier register.
Do Illka and Robin know that there is such a register that can identify different CMN versions? Looking forward to your suggestions.
Ok.+ }
+ else if (cmn->model == CMN650) {
+ return sysfs_emit(buf, "%s\n", "CMN650");
I'd use lowercase names
+ }
+ 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");
can we have a "is_visble" attr to just no show this when unknown?
Ok.
+}
+
+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,
nit: no need for trailing ',' on a sentinel
Ok, Will do.
+};
+
+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
};