kernel: allow delayed work with delays in microseconds

This allows delayed work with delays in microseconds, rather than simply milliseconds. Signed-off-by: Daniel Leung <[email protected]>
dcpleung · Aug 26, 2019 · 9dc2da3 · 9dc2da3
1 parent 5b8377d
commit 9dc2da3
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Showing 2 changed files with 49 additions and 8 deletions.
diff --git a/include/kernel.h b/include/kernel.h
@@ -18,6 +18,8 @@
 #include <errno.h>
 #include <stdbool.h>
 
+#include "sys_clock.h"
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -2902,7 +2904,42 @@ extern void k_delayed_work_init(struct k_delayed_work *work,
 				k_work_handler_t handler);
 
 /**
- * @brief Submit a delayed work item.
+ * @brief Submit a delayed work item (with delay in microseconds).
+ *
+ * This routine schedules work item @a work to be processed by workqueue
+ * @a work_q after a delay of @a delay milliseconds. The routine initiates
+ * an asynchronous countdown for the work item and then returns to the caller.
+ * Only when the countdown completes is the work item actually submitted to
+ * the workqueue and becomes pending.
+ *
+ * Submitting a previously submitted delayed work item that is still
+ * counting down cancels the existing submission and restarts the
+ * countdown using the new delay.  Note that this behavior is
+ * inherently subject to race conditions with the pre-existing
+ * timeouts and work queue, so care must be taken to synchronize such
+ * resubmissions externally.
+ *
+ * @warning
+ * A delayed work item must not be modified until it has been processed
+ * by the workqueue.
+ *
+ * @note Can be called by ISRs.
+ *
+ * @param work_q Address of workqueue.
+ * @param work Address of delayed work item.
+ * @param delay Delay before submitting the work item (in microseconds).
+ *
+ * @retval 0 Work item countdown started.
+ * @retval -EINVAL Work item is being processed or has completed its work.
+ * @retval -EADDRINUSE Work item is pending on a different workqueue.
+ * @req K-DWORK-001
+ */
+extern int k_delayed_work_submit_to_queue_us(struct k_work_q *work_q,
+					     struct k_delayed_work *work,
+					     s32_t us_delay);
+
+/**
+ * @brief Submit a delayed work item (with delay in milliseconds).
  *
  * This routine schedules work item @a work to be processed by workqueue
  * @a work_q after a delay of @a delay milliseconds. The routine initiates
@@ -2932,9 +2969,13 @@ extern void k_delayed_work_init(struct k_delayed_work *work,
  * @retval -EADDRINUSE Work item is pending on a different workqueue.
  * @req K-DWORK-001
  */
-extern int k_delayed_work_submit_to_queue(struct k_work_q *work_q,
-					  struct k_delayed_work *work,
-					  s32_t delay);
+static inline int k_delayed_work_submit_to_queue(struct k_work_q *work_q,
+						 struct k_delayed_work *work,
+						 s32_t delay)
+{
+	return k_delayed_work_submit_to_queue_us(work_q, work,
+						 (delay * USEC_PER_MSEC));
+}
 
 /**
  * @brief Cancel a delayed work item.

diff --git a/kernel/work_q.c b/kernel/work_q.c
@@ -73,9 +73,9 @@ static int work_cancel(struct k_delayed_work *work)
 	return 0;
 }
 
-int k_delayed_work_submit_to_queue(struct k_work_q *work_q,
-				   struct k_delayed_work *work,
-				   s32_t delay)
+int k_delayed_work_submit_to_queue_us(struct k_work_q *work_q,
+				      struct k_delayed_work *work,
+				      s32_t delay)
 {
 	k_spinlock_key_t key = k_spin_lock(&lock);
 	int err = 0;
@@ -108,7 +108,7 @@ int k_delayed_work_submit_to_queue(struct k_work_q *work_q,
 
 	/* Add timeout */
 	z_add_timeout(&work->timeout, work_timeout,
-		     _TICK_ALIGN + z_ms_to_ticks(delay));
+		     _TICK_ALIGN + z_us_to_ticks(delay));
 
 done:
 	k_spin_unlock(&lock, key);