scsi: ufs: core: Add missing post notify for power mode change

When the power mode change is successful but the power mode hasn't
actually changed, the post notification was missed.  Similar to the
approach with hibernate/clock scale/hce enable, having pre/post
notifications in the same function will make it easier to maintain.

Additionally, supplement the description of power parameters for the
pwr_change_notify callback.

Fixes: 7eb584d ("ufs: refactor configuring power mode")
Cc: stable@vger.kernel.org #6.11.x
Signed-off-by: Peter Wang <peter.wang@mediatek.com>
Link: https://lore.kernel.org/r/20241122024943.30589-1-peter.wang@mediatek.com
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: ptr324

drivers/ufs/core/ufshcd.c

@@ -4671,9 +4671,6 @@ static int ufshcd_change_power_mode(struct ufs_hba *hba,
 		dev_err(hba->dev,
 			"%s: power mode change failed %d\n", __func__, ret);
 	} else {
-		ufshcd_vops_pwr_change_notify(hba, POST_CHANGE, NULL,
-								pwr_mode);
-
 		memcpy(&hba->pwr_info, pwr_mode,
 			sizeof(struct ufs_pa_layer_attr));
 	}
@@ -4702,6 +4699,10 @@ int ufshcd_config_pwr_mode(struct ufs_hba *hba,
 
 	ret = ufshcd_change_power_mode(hba, &final_params);
 
+	if (!ret)
+		ufshcd_vops_pwr_change_notify(hba, POST_CHANGE, NULL,
+					&final_params);
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(ufshcd_config_pwr_mode);

include/ufs/ufshcd.h

@@ -310,7 +310,9 @@ struct ufs_pwr_mode_info {
  *                       to allow variant specific Uni-Pro initialization.
  * @pwr_change_notify: called before and after a power mode change
  *			is carried out to allow vendor spesific capabilities
- *			to be set.
+ *			to be set. PRE_CHANGE can modify final_params based
+ *			on desired_pwr_mode, but POST_CHANGE must not alter
+ *			the final_params parameter
  * @setup_xfer_req: called before any transfer request is issued
  *                  to set some things
  * @setup_task_mgmt: called before any task management request is issued
@@ -353,9 +355,9 @@ struct ufs_hba_variant_ops {
 	int	(*link_startup_notify)(struct ufs_hba *,
 				       enum ufs_notify_change_status);
 	int	(*pwr_change_notify)(struct ufs_hba *,
-					enum ufs_notify_change_status status,
-					struct ufs_pa_layer_attr *,
-					struct ufs_pa_layer_attr *);
+				enum ufs_notify_change_status status,
+				struct ufs_pa_layer_attr *desired_pwr_mode,
+				struct ufs_pa_layer_attr *final_params);
 	void	(*setup_xfer_req)(struct ufs_hba *hba, int tag,
 				  bool is_scsi_cmd);
 	void	(*setup_task_mgmt)(struct ufs_hba *, int, u8);