bus: mhi: core: Improve debug messages for power up

Improve error message to be more descriptive if a failure occurs
with an invalid power up execution environment. Additionally, add
a debug log to print the execution environment and MHI state
before a power up is attempted to confirm if the device is in an
expected state. This helps clarify reasons for power up failures
such as the device being found in a PBL or Emergency Download
Mode execution environment and the host expected a full power up
with Pass-Through and no image loading involved.

Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Hemant Kumar <[e-mail]>
Reviewed-by: Jeffrey Hugo <[e-mail]>
Reviewed-by: Manivannan Sadhasivam <[e-mail]>
Signed-off-by: Bhaumik Bhatt <[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/pm.c

···
 
 	/* Confirm that the device is in valid exec env */
 	if (!MHI_IN_PBL(current_ee) && current_ee != MHI_EE_AMSS) {
-		dev_err(dev, "Not a valid EE for power on\n");
+		dev_err(dev, "%s is not a valid EE for power on\n",
+			TO_MHI_EXEC_STR(current_ee));
 		ret = -EIO;
 		goto error_async_power_up;
 	}
 
 	state = mhi_get_mhi_state(mhi_cntrl);
+	dev_dbg(dev, "Attempting power on with EE: %s, state: %s\n",
+		TO_MHI_EXEC_STR(current_ee), TO_MHI_STATE_STR(state));
+
 	if (state == MHI_STATE_SYS_ERR) {
 		mhi_set_mhi_state(mhi_cntrl, MHI_STATE_RESET);
 		ret = wait_event_timeout(mhi_cntrl->state_event,