overlay: Read power from perf_events

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 26 insertions, 0 deletions

diff --git a/overlay/perf.c b/overlay/perf.c
new file mode 100644
index 00000000..b8fdc675
--- /dev/null
+++ b/overlay/perf.c
@@ -0,0 +1,26 @@
+#include <stdint.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include "perf.h"
+
+uint64_t i915_type_id(void)
+{
+	char buf[1024];
+	int fd, n;
+
+	fd = open("/sys/bus/event_source/devices/i915/type", 0);
+	if (fd < 0) {
+		n = -1;
+	} else {
+		n = read(fd, buf, sizeof(buf)-1);
+		close(fd);
+	}
+	if (n < 0)
+		return 0;
+
+	buf[n] = '\0';
+	return strtoull(buf, 0, 0);
+}
+