drivers/perf: hisi_pcie: Export supported Root Ports [bdf_min, bdf_max]

Currently users can get the Root Ports supported by the PCIe PMU by
"bus" sysfs attributes which indicates the PCIe bus number where
Root Ports are located. This maybe insufficient since Root Ports
supported by different PCIe PMUs may be located on the same PCIe bus.
So export the BDF range the Root Ports additionally.

Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240829090332.28756-4-yangyicong@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>

Author: Yicong Yang

Documentation/admin-guide/perf/hisi-pcie-pmu.rst

@@ -28,7 +28,9 @@ The "identifier" sysfs file allows users to identify the version of the
 PMU hardware device.
 
 The "bus" sysfs file allows users to get the bus number of Root Ports
-monitored by PMU.
+monitored by PMU. Furthermore users can get the Root Ports range in
+[bdf_min, bdf_max] from "bdf_min" and "bdf_max" sysfs attributes
+respectively.
 
 Example usage of perf::
 

drivers/perf/hisilicon/hisi_pcie_pmu.c

@@ -141,6 +141,22 @@ static ssize_t bus_show(struct device *dev, struct device_attribute *attr, char
 }
 static DEVICE_ATTR_RO(bus);
 
+static ssize_t bdf_min_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct hisi_pcie_pmu *pcie_pmu = to_pcie_pmu(dev_get_drvdata(dev));
+
+	return sysfs_emit(buf, "%#04x\n", pcie_pmu->bdf_min);
+}
+static DEVICE_ATTR_RO(bdf_min);
+
+static ssize_t bdf_max_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct hisi_pcie_pmu *pcie_pmu = to_pcie_pmu(dev_get_drvdata(dev));
+
+	return sysfs_emit(buf, "%#04x\n", pcie_pmu->bdf_max);
+}
+static DEVICE_ATTR_RO(bdf_max);
+
 static struct hisi_pcie_reg_pair
 hisi_pcie_parse_reg_value(struct hisi_pcie_pmu *pcie_pmu, u32 reg_off)
 {
@@ -763,6 +779,8 @@ static const struct attribute_group hisi_pcie_pmu_format_group = {
 
 static struct attribute *hisi_pcie_pmu_bus_attrs[] = {
 	&dev_attr_bus.attr,
+	&dev_attr_bdf_max.attr,
+	&dev_attr_bdf_min.attr,
 	NULL
 };