Bluetooth: Controller: Run all enqueued mayfly before disable

Controller asserted in preparation of a role event due to
the previous (same or another) role event preparation being
not complete.

Mayfly callee was disabled in the previous event due to the
preparation time being short and previous start running
(higher natural priority) before all previous preparation
mayfly completed. The previous start disabled mayfly to
avoid Radio ISR latencies.

The current role event that asserted, preempted the
previous role (observer role with continuous scanning
window) which runs until preemption to maximise the Radio
h/w use (observer scanning until next interval). The
previous preparation mayfly is still disabled when the
current role preparation tries to use same mayfly instance
which should be free for a new enqueue.

This commit updates mayfly implementation so that mayfly
callee is disabled only after all enqueued mayfly instances
are run to completion.

Jira: ZEP-1839

Change-id: I3e0d31422db8e47b819189110b11ebd07dd09a7c
Signed-off-by: Vinayak Chettimada <[email protected]>

Author: cvinayak

subsys/bluetooth/controller/hci/hci_driver.c

@@ -84,7 +84,7 @@ int bt_rand(void *buf, size_t len)
 	return 0;
 }
 
-void mayfly_enable(uint8_t caller_id, uint8_t callee_id, uint8_t enable)
+void mayfly_enable_cb(uint8_t caller_id, uint8_t callee_id, uint8_t enable)
 {
 	(void)caller_id;
 

subsys/bluetooth/controller/util/mayfly.c

@@ -14,6 +14,13 @@
 static struct {
 	void *head;
 	void *tail;
+	union {
+		uint32_t flags;
+		struct {
+			uint32_t disable_req : 1;
+			uint32_t disable_ack : 1;
+		};
+	};
 } mft[MAYFLY_CALLEE_COUNT][MAYFLY_CALLER_COUNT];
 
 static void *mfl[MAYFLY_CALLEE_COUNT][MAYFLY_CALLER_COUNT][2];
@@ -35,6 +42,20 @@ void mayfly_init(void)
 	}
 }
 
+void mayfly_enable(uint8_t caller_id, uint8_t callee_id, uint8_t enable)
+{
+	if (enable) {
+		mayfly_enable_cb(caller_id, callee_id, enable);
+	} else {
+		if (mft[callee_id][caller_id].disable_req ==
+		    mft[callee_id][caller_id].disable_ack) {
+			mft[callee_id][caller_id].disable_req++;
+
+			mayfly_pend(caller_id, callee_id);
+		}
+	}
+}
+
 uint32_t mayfly_enqueue(uint8_t caller_id, uint8_t callee_id, uint8_t chain,
 			struct mayfly *m)
 {
@@ -90,6 +111,7 @@ uint32_t mayfly_enqueue(uint8_t caller_id, uint8_t callee_id, uint8_t chain,
 void mayfly_run(uint8_t callee_id)
 {
 	uint8_t caller_id;
+	uint8_t disable = 0;
 
 	/* iterate through each caller queue to this callee_id */
 	caller_id = MAYFLY_CALLER_COUNT;
@@ -140,14 +162,27 @@ void mayfly_run(uint8_t callee_id)
 			 */
 			if (state == 1) {
 				/* pend callee (tailchain) if mayfly queue is
-				 * not empty.
+				 * not empty or all caller queues are not
+				 * processed.
 				 */
-				if (link) {
+				if (caller_id || link) {
 					mayfly_pend(callee_id, callee_id);
-				}
 
-				return;
+					return;
+				}
 			}
 		}
+
+		if (mft[callee_id][caller_id].disable_req !=
+		    mft[callee_id][caller_id].disable_ack) {
+			disable = 1;
+
+			mft[callee_id][caller_id].disable_ack =
+				mft[callee_id][caller_id].disable_req;
+		}
+	}
+
+	if (disable) {
+		mayfly_enable_cb(callee_id, callee_id, 0);
 	}
 }

subsys/bluetooth/controller/util/mayfly.h

@@ -17,11 +17,13 @@ struct mayfly {
 };
 
 void mayfly_init(void);
+void mayfly_enable(uint8_t caller_id, uint8_t callee_id, uint8_t enable);
 uint32_t mayfly_enqueue(uint8_t caller_id, uint8_t callee_id, uint8_t chain,
 			struct mayfly *m);
 void mayfly_run(uint8_t callee_id);
 
-extern void mayfly_enable(uint8_t caller_id, uint8_t callee_id, uint8_t enable);
+extern void mayfly_enable_cb(uint8_t caller_id, uint8_t callee_id,
+			     uint8_t enable);
 extern uint32_t mayfly_is_enabled(uint8_t caller_id, uint8_t callee_id);
 extern uint32_t mayfly_prio_is_equal(uint8_t caller_id, uint8_t callee_id);
 extern void mayfly_pend(uint8_t caller_id, uint8_t callee_id);