[PATCH i-g-t 1/3] lib/igt_perf: Add helper functions to read format entries

[Riana Tauro]

add helper functions to read format entries of pmu

Signed-off-by: Riana Tauro <riana.tauro at intel.com>
---
 lib/igt_perf.c | 23 +++++++++++++++++++++++
 lib/igt_perf.h |  1 +
 2 files changed, 24 insertions(+)

diff --git a/lib/igt_perf.c b/lib/igt_perf.c
index 3866c6d77..7d2ff8969 100644
--- a/lib/igt_perf.c
+++ b/lib/igt_perf.c
@@ -129,6 +129,29 @@ uint64_t igt_perf_type_id(const char *device)
 	return strtoull(buf, NULL, 0);
 }
 
+int igt_perf_format(const char *device, const char *name, char *buff, int buflen)
+{
+	char buf[NAME_MAX];
+	ssize_t ret;
+	int fd;
+
+	snprintf(buf, sizeof(buf),
+		 "/sys/bus/event_source/devices/%s/format/%s", device, name);
+
+	fd = open(buf, O_RDONLY);
+	if (fd < 0)
+		return -1;
+
+	ret = read(fd, buff, buflen - 1);
+	close(fd);
+	if (ret < 1)
+		return -1;
+
+	buf[ret] = '\0';
+
+	return 0;
+}
+
 int igt_perf_events_dir(int i915)
 {
 	char buf[80];
diff --git a/lib/igt_perf.h b/lib/igt_perf.h
index 3d9ba2917..c9c6b27f7 100644
--- a/lib/igt_perf.h
+++ b/lib/igt_perf.h
@@ -57,6 +57,7 @@ uint64_t igt_perf_type_id(const char *device);
 int igt_perf_events_dir(int i915);
 int igt_perf_open(uint64_t type, uint64_t config);
 int igt_perf_open_group(uint64_t type, uint64_t config, int group);
+int igt_perf_format(const char *device, const char *name, char *buff, int buflen);
 
 const char *i915_perf_device(int i915, char *buf, int buflen);
 uint64_t i915_perf_type_id(int i915);
-- 
2.47.1