[RFC v3 1/4] drivers/nvdimm: Add nvdimm pmu structure

From: Kajol Jain
Date: Sat May 29 2021 - 03:39:48 EST


A structure is added called nvdimm_pmu for performance
stats reporting support of nvdimm devices. It can be used to add
nvdimm pmu data such as supported events and pmu event functions
like event_init/add/read/del with cpu hotplug support.

Signed-off-by: Kajol Jain <kjain@xxxxxxxxxxxxx>
---
include/linux/nd.h | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)

diff --git a/include/linux/nd.h b/include/linux/nd.h
index ee9ad76afbba..3baeeb7c3c41 100644
--- a/include/linux/nd.h
+++ b/include/linux/nd.h
@@ -8,6 +8,8 @@
#include <linux/ndctl.h>
#include <linux/device.h>
#include <linux/badblocks.h>
+#include <linux/platform_device.h>
+#include <linux/perf_event.h>

enum nvdimm_event {
NVDIMM_REVALIDATE_POISON,
@@ -23,6 +25,43 @@ enum nvdimm_claim_class {
NVDIMM_CCLASS_UNKNOWN,
};

+/* Event attribute array index */
+#define NVDIMM_PMU_FORMAT_ATTR 0
+#define NVDIMM_PMU_EVENT_ATTR 1
+#define NVDIMM_PMU_CPUMASK_ATTR 2
+#define NVDIMM_PMU_NULL_ATTR 3
+
+/**
+ * struct nvdimm_pmu - data structure for nvdimm perf driver
+ *
+ * @name: name of the nvdimm pmu device.
+ * @pmu: pmu data structure for nvdimm performance stats.
+ * @dev: nvdimm device pointer.
+ * @functions(event_init/add/del/read): platform specific pmu functions.
+ * @attr_groups: data structure for events, formats and cpumask
+ * @cpu: designated cpu for counter access.
+ * @node: node for cpu hotplug notifier link.
+ * @cpuhp_state: state for cpu hotplug notification.
+ */
+struct nvdimm_pmu {
+ const char *name;
+ struct pmu pmu;
+ struct device *dev;
+ int (*event_init)(struct perf_event *event);
+ int (*add)(struct perf_event *event, int flags);
+ void (*del)(struct perf_event *event, int flags);
+ void (*read)(struct perf_event *event);
+ /*
+ * Attribute groups for the nvdimm pmu. Index 0 used for
+ * format attribute, index 1 used for event attribute,
+ * index 2 used for cpusmask attribute and index 3 kept as NULL.
+ */
+ const struct attribute_group *attr_groups[4];
+ int cpu;
+ struct hlist_node node;
+ enum cpuhp_state cpuhp_state;
+};
+
struct nd_device_driver {
struct device_driver drv;
unsigned long type;
--
2.27.0