msm: camera: reqmgr: Add protection for workqueue congestion

When workqueue is congested, CRM may apply same
request to device which will trigger recovery
due to apply fails. This change prevent CRM
triggering recovery if the time interval of
continuous applying req less than 5ms.

CRs-Fixed: 2775372
Change-Id: I45c2ed76334b1bbf4547bbf21f90cf0a6c169323
Signed-off-by: Depeng Shao <[email protected]>

drivers/cam_req_mgr/cam_req_mgr_core.c

@@ -53,6 +53,7 @@ void cam_req_mgr_core_link_reset(struct cam_req_mgr_core_link *link)
 	link->prev_sof_timestamp = 0;
 	link->skip_init_frame = false;
 	link->num_sync_links = 0;
+	link->last_applied_jiffies = 0;
 	atomic_set(&link->eof_event_cnt, 0);
 
 	for (pd = 0; pd < CAM_PIPELINE_DELAY_MAX; pd++) {
@@ -1584,6 +1585,7 @@ static int __cam_req_mgr_process_req(struct cam_req_mgr_core_link *link,
 {
 	int                                  rc = 0, idx, i;
 	int                                  reset_step = 0;
+	bool                                 check_retry_cnt = false;
 	uint32_t                             trigger = trigger_data->trigger;
 	struct cam_req_mgr_slot             *slot = NULL;
 	struct cam_req_mgr_req_queue        *in_q;
@@ -1694,10 +1696,14 @@ static int __cam_req_mgr_process_req(struct cam_req_mgr_core_link *link,
 
 	rc = __cam_req_mgr_send_req(link, link->req.in_q, trigger, &dev);
 	if (rc < 0) {
-		if (in_q->last_applied_idx < in_q->rd_idx) {
-			/* Apply req failed retry at next sof */
-			slot->status = CRM_SLOT_STATUS_REQ_PENDING;
+		/* Apply req failed retry at next sof */
+		slot->status = CRM_SLOT_STATUS_REQ_PENDING;
+
+		if (jiffies_to_msecs(jiffies - link->last_applied_jiffies) >
+			MINIMUM_WORKQUEUE_SCHED_TIME_IN_MS)
+			check_retry_cnt = true;
 
+		if ((in_q->last_applied_idx < in_q->rd_idx) && check_retry_cnt) {
 			link->retry_cnt++;
 			if (link->retry_cnt == MAXIMUM_RETRY_ATTEMPTS) {
 				CAM_DBG(CAM_CRM,
@@ -1771,6 +1777,16 @@ static int __cam_req_mgr_process_req(struct cam_req_mgr_core_link *link,
 		}
 	}
 
+	/*
+	 * Only update the jiffies of last applied request
+	 * for SOF trigger, since it is used to protect from
+	 * applying fails in ISP which is triggered at SOF.
+	 * And, also don't need to do update for error case
+	 * since error case doesn't check the retry count.
+	 */
+	if (trigger == CAM_TRIGGER_POINT_SOF)
+		link->last_applied_jiffies = jiffies;
+
 	mutex_unlock(&session->lock);
 	return rc;
 error:

drivers/cam_req_mgr/cam_req_mgr_core.h

@@ -36,6 +36,8 @@
 
 #define MAXIMUM_RETRY_ATTEMPTS 2
 
+#define MINIMUM_WORKQUEUE_SCHED_TIME_IN_MS 5
+
 #define VERSION_1  1
 #define VERSION_2  2
 #define CAM_REQ_MGR_MAX_TRIGGERS   2
@@ -371,6 +373,7 @@ struct cam_req_mgr_connected_device {
  * @eof_event_cnt        : Atomic variable to track the number of EOF requests
  * @skip_init_frame      : skip initial frames crm_wd_timer validation in the
  *                         case of long exposure use case
+ * @last_applied_jiffies : Record the jiffies of last applied req
  */
 struct cam_req_mgr_core_link {
 	int32_t                              link_hdl;
@@ -407,6 +410,7 @@ struct cam_req_mgr_core_link {
 	uint32_t    trigger_cnt[CAM_REQ_MGR_MAX_TRIGGERS];
 	atomic_t                             eof_event_cnt;
 	bool                                 skip_init_frame;
+	uint64_t                             last_applied_jiffies;
 };
 
 /**