[PATCH v2 5/7]powerpc/powernv: add event attribute and group to nest pmu

[Madhavan Srinivasan <maddy@linux.vnet.ibm.com>]

Add code to create event attribute and attribute group for
each nest pmu.

Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
---
 arch/powerpc/perf/nest-pmu.c | 55 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 54 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/perf/nest-pmu.c b/arch/powerpc/perf/nest-pmu.c
index 43d5fde..8fad2d9 100644
--- a/arch/powerpc/perf/nest-pmu.c
+++ b/arch/powerpc/perf/nest-pmu.c
@@ -13,6 +13,55 @@
 static struct perchip_nest_info p8_perchip_nest_info[P8_MAX_CHIP];
 static struct nest_pmu *per_nest_pmu_arr[P8_MAX_NEST_PMUS];
 
+/*
+ * Populate event name and string in attribute
+ */
+struct attribute *dev_str_attr(const char *name, const char *str)
+{
+	struct perf_pmu_events_attr *attr;
+
+	attr = kzalloc(sizeof(*attr), GFP_KERNEL);
+
+	attr->event_str = str;
+	attr->attr.attr.name = name;
+	attr->attr.attr.mode = 0444;
+	attr->attr.show = perf_event_sysfs_show;
+
+	return &attr->attr.attr;
+}
+
+int update_events_in_group(
+	struct ppc64_nest_ima_events *p8_events, int idx,
+		struct nest_pmu *pmu)
+{
+	struct attribute_group *attr_group;
+	struct attribute **attrs;
+	int i;
+
+	/* Allocate memory add supported event as event attribute */
+	attr_group = kzalloc(((sizeof(struct attribute *) * (idx + 1)) +
+				sizeof(*attr_group)), GFP_KERNEL);
+	if (!attr_group)
+		return -ENOMEM;
+
+	attrs = (struct attribute **)(attr_group + 1);
+	attr_group->name = "events";
+
+	/*
+	 * struct attribute group contains,  "name" and an
+	 * array of attributes, along other elemsnts.
+	 * link attrs with attribute group's attr array.
+	 */
+	attr_group->attrs = attrs;
+
+	for (i = 0; i < idx; i++, p8_events++)
+		attrs[i] = dev_str_attr((char *)p8_events->ev_name,
+					(char *)p8_events->ev_value);
+
+	pmu->attr_groups[0] = attr_group;
+	return 0;
+}
+
 static int nest_pmu_create(struct device_node *dev, int pmu_index)
 {
 	struct ppc64_nest_ima_events **p8_events_arr, *p8_events;
@@ -68,7 +117,7 @@ static int nest_pmu_create(struct device_node *dev, int pmu_index)
 
 		buf = kzalloc(MAX_PMU_NAME_LEN, GFP_KERNEL);
 		if (!buf)
-		return -ENOMEM;
+			return -ENOMEM;
 
 		if (strncmp(pp->name, "unit.", 5) == 0) {
 			start += 5;
@@ -126,6 +175,10 @@ static int nest_pmu_create(struct device_node *dev, int pmu_index)
 		}
 	}
 
+	update_events_in_group(
+		(struct ppc64_nest_ima_events *)p8_events_arr,
+							idx, pmu_ptr);
+
 	return 0;
 }
 
-- 
1.9.1