[PATCH] implement set_enabled functions on powercap.c

[Vishnu Sanal T <t.v.s10123@gmail.com>]

Implement the functions sysfs_set_enabled, powercap_set_enabled,
and powercap_zone_set_enabled on powercap.c.

Signed-off-by: Vishnu Sanal T <t.v.s10123@gmail.com>
---
 tools/power/cpupower/lib/powercap.c | 43 +++++++++++++++++++++++++----
 1 file changed, 37 insertions(+), 6 deletions(-)

diff --git a/tools/power/cpupower/lib/powercap.c b/tools/power/cpupower/lib/powercap.c
index 94a0c69e55ef..1cf2b0de5536 100644
--- a/tools/power/cpupower/lib/powercap.c
+++ b/tools/power/cpupower/lib/powercap.c
@@ -70,6 +70,29 @@ static int sysfs_get_enabled(char *path, int *mode)
 	return ret;
 }
 
+static int sysfs_set_enabled(char *path, int mode)
+{
+	int fd;
+	char yes_no = (char) (mode + '0');
+	int ret = 0;
+
+	fd = open(path, O_RDWR);
+	if (fd == -1) {
+		ret = -1;
+		goto out;
+	}
+
+	if (write(fd, &yes_no, 1) != 1) {
+		ret = -1;
+		goto out_close;
+	}
+
+out_close:
+	close(fd);
+out:
+	return ret;
+}
+
 int powercap_get_enabled(int *mode)
 {
 	char path[SYSFS_PATH_MAX] = PATH_TO_POWERCAP "/intel-rapl/enabled";
@@ -77,12 +100,11 @@ int powercap_get_enabled(int *mode)
 	return sysfs_get_enabled(path, mode);
 }
 
-/*
- * TODO: implement function. Returns dummy 0 for now.
- */
 int powercap_set_enabled(int mode)
 {
-	return 0;
+	char path[SYSFS_PATH_MAX] = PATH_TO_POWERCAP "/intel-rapl/enabled";
+
+	return sysfs_set_enabled(path, mode);
 }
 
 /*
@@ -180,8 +202,17 @@ int powercap_zone_get_enabled(struct powercap_zone *zone, int *mode)
 
 int powercap_zone_set_enabled(struct powercap_zone *zone, int mode)
 {
-	/* To be done if needed */
-	return 0;
+	char path[SYSFS_PATH_MAX] = PATH_TO_POWERCAP;
+
+	if ((strlen(PATH_TO_POWERCAP) + strlen(zone->sys_name)) +
+	    strlen("/enabled") + 1 >= SYSFS_PATH_MAX)
+		return -1;
+
+	strcat(path, "/");
+	strcat(path, zone->sys_name);
+	strcat(path, "/enabled");
+
+	return sysfs_set_enabled(path, mode);
 }
 
 
-- 
2.47.0