bus: mhi: core: Remove the system error worker thread

Remove the system error worker thread and instead have the
execution environment worker handle that transition to serialize
processing and avoid any possible race conditions during
shutdown.

Signed-off-by: Hemant Kumar <[e-mail]>
Reviewed-by: Jeffrey Hugo <[e-mail]>
Reviewed-by: Manivannan Sadhasivam <[e-mail]>
Signed-off-by: Manivannan Sadhasivam <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/bus/mhi/core/init.c

···
 	[DEV_ST_TRANSITION_READY] = "READY",
 	[DEV_ST_TRANSITION_SBL] = "SBL",
 	[DEV_ST_TRANSITION_MISSION_MODE] = "MISSION_MODE",
+	[DEV_ST_TRANSITION_SYS_ERR] = "SYS_ERR",
 };
 
 const char * const mhi_state_str[MHI_STATE_MAX] = {
···
 	spin_lock_init(&mhi_cntrl->transition_lock);
 	spin_lock_init(&mhi_cntrl->wlock);
 	INIT_WORK(&mhi_cntrl->st_worker, mhi_pm_st_worker);
-	INIT_WORK(&mhi_cntrl->syserr_worker, mhi_pm_sys_err_worker);
 	init_waitqueue_head(&mhi_cntrl->state_event);
 
 	mhi_cmd = mhi_cntrl->mhi_cmd;

drivers/bus/mhi/core/internal.h

···
 	DEV_ST_TRANSITION_READY,
 	DEV_ST_TRANSITION_SBL,
 	DEV_ST_TRANSITION_MISSION_MODE,
+	DEV_ST_TRANSITION_SYS_ERR,
 	DEV_ST_TRANSITION_MAX,
 };
 
···
 int mhi_queue_state_transition(struct mhi_controller *mhi_cntrl,
 			       enum dev_st_transition state);
 void mhi_pm_st_worker(struct work_struct *work);
-void mhi_pm_sys_err_worker(struct work_struct *work);
+void mhi_pm_sys_err_handler(struct mhi_controller *mhi_cntrl);
 void mhi_fw_load_worker(struct work_struct *work);
 int mhi_ready_state_transition(struct mhi_controller *mhi_cntrl);
 void mhi_ctrl_ev_task(unsigned long data);

drivers/bus/mhi/core/main.c

···
 		if (MHI_IN_PBL(ee))
 			mhi_cntrl->status_cb(mhi_cntrl, MHI_CB_FATAL_ERROR);
 		else
-			schedule_work(&mhi_cntrl->syserr_worker);
+			mhi_pm_sys_err_handler(mhi_cntrl);
 	}
 
 exit_intvec:
···
 							MHI_PM_SYS_ERR_DETECT);
 				write_unlock_irq(&mhi_cntrl->pm_lock);
 				if (new_state == MHI_PM_SYS_ERR_DETECT)
-					schedule_work(&mhi_cntrl->syserr_worker);
+					mhi_pm_sys_err_handler(mhi_cntrl);
 				break;
 			}
 			default:
···
 		}
 		write_unlock_irq(&mhi_cntrl->pm_lock);
 		if (pm_state == MHI_PM_SYS_ERR_DETECT)
-			schedule_work(&mhi_cntrl->syserr_worker);
+			mhi_pm_sys_err_handler(mhi_cntrl);
 	}
 }
 

drivers/bus/mhi/core/pm.c

···
 		to_mhi_pm_state_str(transition_state));
 
 	/* We must notify MHI control driver so it can clean up first */
-	if (transition_state == MHI_PM_SYS_ERR_PROCESS) {
-		/*
-		 * If controller supports RDDM, we do not process
-		 * SYS error state, instead we will jump directly
-		 * to RDDM state
-		 */
-		if (mhi_cntrl->rddm_image) {
-			dev_dbg(dev,
-				 "Controller supports RDDM, so skip SYS_ERR\n");
-			return;
-		}
+	if (transition_state == MHI_PM_SYS_ERR_PROCESS)
 		mhi_cntrl->status_cb(mhi_cntrl, MHI_CB_SYS_ERROR);
-	}
 
 	mutex_lock(&mhi_cntrl->pm_mutex);
 	write_lock_irq(&mhi_cntrl->pm_lock);
···
 	mutex_unlock(&mhi_cntrl->pm_mutex);
 	dev_dbg(dev, "Waiting for all pending threads to complete\n");
 	wake_up_all(&mhi_cntrl->state_event);
-	flush_work(&mhi_cntrl->st_worker);
 
 	dev_dbg(dev, "Reset all active channels and remove MHI devices\n");
 	device_for_each_child(mhi_cntrl->cntrl_dev, NULL, mhi_destroy_device);
···
 }
 
 /* SYS_ERR worker */
-void mhi_pm_sys_err_worker(struct work_struct *work)
+void mhi_pm_sys_err_handler(struct mhi_controller *mhi_cntrl)
 {
-	struct mhi_controller *mhi_cntrl = container_of(work,
-							struct mhi_controller,
-							syserr_worker);
+	struct device *dev = &mhi_cntrl->mhi_dev->dev;
 
-	mhi_pm_disable_transition(mhi_cntrl, MHI_PM_SYS_ERR_PROCESS);
+	/* skip if controller supports RDDM */
+	if (mhi_cntrl->rddm_image) {
+		dev_dbg(dev, "Controller supports RDDM, skip SYS_ERROR\n");
+		return;
+	}
+
+	mhi_queue_state_transition(mhi_cntrl, DEV_ST_TRANSITION_SYS_ERR);
 }
 
 /* Device State Transition worker */
···
 			break;
 		case DEV_ST_TRANSITION_READY:
 			mhi_ready_state_transition(mhi_cntrl);
+			break;
+		case DEV_ST_TRANSITION_SYS_ERR:
+			mhi_pm_disable_transition
+				(mhi_cntrl, MHI_PM_SYS_ERR_PROCESS);
 			break;
 		default:
 			break;

include/linux/mhi.h

···
  * @wlock: Lock for protecting device wakeup
  * @mhi_link_info: Device bandwidth info
  * @st_worker: State transition worker
- * @syserr_worker: System error worker
  * @state_event: State change event
  * @status_cb: CB function to notify power states of the device (required)
  * @wake_get: CB function to assert device wake (optional)
···
 	spinlock_t wlock;
 	struct mhi_link_info mhi_link_info;
 	struct work_struct st_worker;
-	struct work_struct syserr_worker;
 	wait_queue_head_t state_event;
 
 	void (*status_cb)(struct mhi_controller *mhi_cntrl,