4 files changed, 53 insertions, 2 deletions

diff --git a/drivers/scsi/ufs/ufs-debugfs.c b/drivers/scsi/ufs/ufs-debugfs.c
index 59729073b569..ced9ef4d7c78 100644
--- a/drivers/scsi/ufs/ufs-debugfs.c
+++ b/drivers/scsi/ufs/ufs-debugfs.c
@@ -88,15 +88,59 @@ static int ee_usr_mask_set(void *data, u64 val)
 
 DEFINE_DEBUGFS_ATTRIBUTE(ee_usr_mask_fops, ee_usr_mask_get, ee_usr_mask_set, "%#llx\n");
 
+void ufs_debugfs_exception_event(struct ufs_hba *hba, u16 status)
+{
+	bool chgd = false;
+	u16 ee_ctrl_mask;
+	int err = 0;
+
+	if (!hba->debugfs_ee_rate_limit_ms || !status)
+		return;
+
+	mutex_lock(&hba->ee_ctrl_mutex);
+	ee_ctrl_mask = hba->ee_drv_mask | (hba->ee_usr_mask & ~status);
+	chgd = ee_ctrl_mask != hba->ee_ctrl_mask;
+	if (chgd) {
+		err = __ufshcd_write_ee_control(hba, ee_ctrl_mask);
+		if (err)
+			dev_err(hba->dev, "%s: failed to write ee control %d\n",
+				__func__, err);
+	}
+	mutex_unlock(&hba->ee_ctrl_mutex);
+
+	if (chgd && !err) {
+		unsigned long delay = msecs_to_jiffies(hba->debugfs_ee_rate_limit_ms);
+
+		queue_delayed_work(system_freezable_wq, &hba->debugfs_ee_work, delay);
+	}
+}
+
+static void ufs_debugfs_restart_ee(struct work_struct *work)
+{
+	struct ufs_hba *hba = container_of(work, struct ufs_hba, debugfs_ee_work.work);
+
+	if (!hba->ee_usr_mask || pm_runtime_suspended(hba->dev) ||
+	    ufs_debugfs_get_user_access(hba))
+		return;
+	ufshcd_write_ee_control(hba);
+	ufs_debugfs_put_user_access(hba);
+}
+
 void ufs_debugfs_hba_init(struct ufs_hba *hba)
 {
+	/* Set default exception event rate limit period to 20ms */
+	hba->debugfs_ee_rate_limit_ms = 20;
+	INIT_DELAYED_WORK(&hba->debugfs_ee_work, ufs_debugfs_restart_ee);
 	hba->debugfs_root = debugfs_create_dir(dev_name(hba->dev), ufs_debugfs_root);
 	debugfs_create_file("stats", 0400, hba->debugfs_root, hba, &ufs_debugfs_stats_fops);
 	debugfs_create_file("exception_event_mask", 0600, hba->debugfs_root,
 			    hba, &ee_usr_mask_fops);
+	debugfs_create_u32("exception_event_rate_limit_ms", 0600, hba->debugfs_root,
+			   &hba->debugfs_ee_rate_limit_ms);
 }
 
 void ufs_debugfs_hba_exit(struct ufs_hba *hba)
 {
 	debugfs_remove_recursive(hba->debugfs_root);
+	cancel_delayed_work_sync(&hba->debugfs_ee_work);
 }
diff --git a/drivers/scsi/ufs/ufs-debugfs.h b/drivers/scsi/ufs/ufs-debugfs.h
index f35b39c4b4f5..3ca29d30460a 100644
--- a/drivers/scsi/ufs/ufs-debugfs.h
+++ b/drivers/scsi/ufs/ufs-debugfs.h
@@ -12,11 +12,13 @@ void __init ufs_debugfs_init(void);
 void __exit ufs_debugfs_exit(void);
 void ufs_debugfs_hba_init(struct ufs_hba *hba);
 void ufs_debugfs_hba_exit(struct ufs_hba *hba);
+void ufs_debugfs_exception_event(struct ufs_hba *hba, u16 status);
 #else
 static inline void ufs_debugfs_init(void) {}
 static inline void ufs_debugfs_exit(void) {}
 static inline void ufs_debugfs_hba_init(struct ufs_hba *hba) {}
 static inline void ufs_debugfs_hba_exit(struct ufs_hba *hba) {}
+static inline void ufs_debugfs_exception_event(struct ufs_hba *hba, u16 status) {}
 #endif
 
 #endif
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index ac16c9af83b8..5c6a364de144 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5162,14 +5162,14 @@ static irqreturn_t ufshcd_transfer_req_compl(struct ufs_hba *hba)
 	}
 }
 
-static int __ufshcd_write_ee_control(struct ufs_hba *hba, u32 ee_ctrl_mask)
+int __ufshcd_write_ee_control(struct ufs_hba *hba, u32 ee_ctrl_mask)
 {
 	return ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
 				       QUERY_ATTR_IDN_EE_CONTROL, 0, 0,
 				       &ee_ctrl_mask);
 }
 
-static int ufshcd_write_ee_control(struct ufs_hba *hba)
+int ufshcd_write_ee_control(struct ufs_hba *hba)
 {
 	int err;
 
@@ -5637,6 +5637,7 @@ static void ufshcd_exception_event_handler(struct work_struct *work)
 	if (status & hba->ee_drv_mask & MASK_EE_URGENT_BKOPS)
 		ufshcd_bkops_exception_event_handler(hba);
 
+	ufs_debugfs_exception_event(hba, status);
 out:
 	ufshcd_scsi_unblock_requests(hba);
 	/*
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 9011a6dee16e..1af91661dc83 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -843,6 +843,8 @@ struct ufs_hba {
 #endif
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *debugfs_root;
+	struct delayed_work debugfs_ee_work;
+	u32 debugfs_ee_rate_limit_ms;
 #endif
 };
 
@@ -1288,6 +1290,8 @@ static inline u8 ufshcd_scsi_to_upiu_lun(unsigned int scsi_lun)
 int ufshcd_dump_regs(struct ufs_hba *hba, size_t offset, size_t len,
 		     const char *prefix);
 
+int __ufshcd_write_ee_control(struct ufs_hba *hba, u32 ee_ctrl_mask);
+int ufshcd_write_ee_control(struct ufs_hba *hba);
 int ufshcd_update_ee_control(struct ufs_hba *hba, u16 *mask, u16 *other_mask,
 			     u16 set, u16 clr);