Change in coreboot[master]: include/timer.h: Add wait_cond_timeout_usecs macro

[Tristan Hsieh (Code Review)]

Tristan Hsieh has uploaded this change for review. ( https://review.coreboot.org/29315

Change subject: include/timer.h: Add wait_cond_timeout_usecs macro
......................................................................

include/timer.h: Add wait_cond_timeout_usecs macro

Add wait_cond_timeout_usecs and wait_cond_timeout_msecs to wait until a
condition gets true or a timeout elapses.

BUG=b:80501386
BRANCH=none
TEST=Built and booted on Kukui

Change-Id: I6de38ee00673c46332ae92b8a11099485de5327a
Signed-off-by: Tristan Shieh 
---
M src/include/timer.h
1 file changed, 43 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/15/29315/1

diff --git a/src/include/timer.h b/src/include/timer.h
index 49eae5e..a5ee72b 100644
--- a/src/include/timer.h
+++ b/src/include/timer.h
@@ -195,4 +195,47 @@
    return stopwatch_duration_usecs(sw) / USECS_PER_MSEC;
 }

+/*
+ * Return remaining time.
+ */
+static inline long stopwatch_remain_usecs(struct stopwatch *sw)
+{
+	return mono_time_diff_microseconds(&sw->current, &sw->expires);
+}
+
+static inline long stopwatch_remain_msecs(struct stopwatch *sw)
+{
+	return stopwatch_remain_usecs(sw) / USECS_PER_MSEC;
+}
+
+/*
+ * Wait until a condition gets true or a timeout elapses.
+ *
+ * condition: a C expression to wait for
+ * timeout: timeout, in microseconds
+ *
+ * Returns:
+ * 0 if the condition evaluated to false after the timeout elapsed,
+ * 1 if the condition evaluated to true after the timeout elapsed,
+ * or the remaining microseconds (at least 1) if the condition evaluated
+ * to true before the timeout elapsed.
+ */
+#define wait_cond_usecs(condition, timeout)			\
+({								\
+	long __ret = 0;						\
+	struct stopwatch __sw;					\
+	stopwatch_init_usecs_expire(&__sw, timeout);		\
+	do {							\
+		if (condition) {				\
+			__ret = stopwatch_expired(&__sw) ? 1 :	\
+				stopwatch_remain_usecs(&__sw);	\
+			break;					\
+		}						\
+	} while (!stopwatch_expired(&__sw));			\
+	__ret;							\
+})
+
+#define wait_cond_msecs(condition, timeout)			\
+	wait_cond_usecs(condition, (timeout) * USECS_PER_MSEC)
+
 #endif /* TIMER_H */