power: Use monotonic time for interaction boost

Using the wall clock will cause boosts to be disabled
when/if the clock is adjusted backward.

Bug: 29191415
Bug: 29208304
Change-Id: I8af5f40b46d996ce7bccb8324fc186e2f3a5b267
(cherry picked from commit 2bf13f822cf39123ee0e97e40caf1288ba4f457a)

1 files changed, 10 insertions, 0 deletions

diff --git a/utils.c b/utils.c
index ce2f2a9..38b5803 100644
--- a/utils.c
+++ b/utils.c
@@ -43,6 +43,9 @@
 #define LOG_TAG "QTI PowerHAL"
 #include <log/log.h>
 
+#define USINSEC 1000000L
+#define NSINUS 1000L
+
 #define SOC_ID_0 "/sys/devices/soc0/soc_id"
 #define SOC_ID_1 "/sys/devices/system/soc/soc0/id"
 
@@ -359,3 +362,10 @@ int get_soc_id(void) {
     close(fd);
     return soc_id;
 }
+
+long long calc_timespan_us(struct timespec start, struct timespec end) {
+    long long diff_in_us = 0;
+    diff_in_us += (end.tv_sec - start.tv_sec) * USINSEC;
+    diff_in_us += (end.tv_nsec - start.tv_nsec) / NSINUS;
+    return diff_in_us;
+}