bus: mhi: core: Handle syserr during power_up

The MHI device may be in the syserr state when we attempt to init it in
power_up().  Since we have no local state, the handling is simple -
reset the device and wait for it to transition out of the reset state.

Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: Hemant Kumar <hemantk@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200521170249.21795-15-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/bus/mhi/core/pm.c

@@ -906,6 +906,7 @@ static void mhi_deassert_dev_wake(struct mhi_controller *mhi_cntrl,
 
 int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
 {
+	enum mhi_state state;
 	enum mhi_ee_type current_ee;
 	enum dev_st_transition next_state;
 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
@@ -975,6 +976,32 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
 		goto error_bhi_offset;
 	}
 
+	state = mhi_get_mhi_state(mhi_cntrl);
+	if (state == MHI_STATE_SYS_ERR) {
+		mhi_set_mhi_state(mhi_cntrl, MHI_STATE_RESET);
+		ret = wait_event_timeout(mhi_cntrl->state_event,
+				MHI_PM_IN_FATAL_STATE(mhi_cntrl->pm_state) ||
+					mhi_read_reg_field(mhi_cntrl,
+							   mhi_cntrl->regs,
+							   MHICTRL,
+							   MHICTRL_RESET_MASK,
+							   MHICTRL_RESET_SHIFT,
+							   &val) ||
+					!val,
+				msecs_to_jiffies(mhi_cntrl->timeout_ms));
+		if (ret) {
+			ret = -EIO;
+			dev_info(dev, "Failed to reset MHI due to syserr state\n");
+			goto error_bhi_offset;
+		}
+
+		/*
+		 * device cleares INTVEC as part of RESET processing,
+		 * re-program it
+		 */
+		mhi_write_reg(mhi_cntrl, mhi_cntrl->bhi, BHI_INTVEC, 0);
+	}
+
 	/* Transition to next state */
 	next_state = MHI_IN_PBL(current_ee) ?
 		DEV_ST_TRANSITION_PBL : DEV_ST_TRANSITION_READY;