scsi: ufs: core: Introduce a new ufshcd vops negotiate_pwr_mode()

Most vendor specific implemenations of vops pwr_change_notify(PRE_CHANGE)
are fulfilling two things at once:

 - Vendor specific target power mode negotiation

 - Vendor specific power mode change preparation

When TX Equalization is added into consideration, before power mode change
to a target power mode, TX Equalization Training (EQTR) needs be done for
that target power mode. In addition, UFSHCI spec requires to start TX EQTR
from HS-G1 (the most reliable High Speed Gear).

Adding TX EQTR before pwr_change_notify(PRE_CHANGE) is not applicable
because we don't know the negotiated power mode yet.

Adding TX EQTR post pwr_change_notify(PRE_CHANGE) is inappropriate because
pwr_change_notify(PRE_CHANGE) has finished preparation for a power mode
change to negotiated power mode, yet we are changing power mode to HS-G1
for TX EQTR.

Add a new vops negotiate_pwr_mode() so that vendor specific power mode
negotiation can be fulfilled in its vendor specific implementations.  Later
on, TX EQTR can be added post vops negotiate_pwr_mode() and before vops
pwr_change_notify(PRE_CHANGE).

Reviewed-by: Bean Huo <beanhuo@micron.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Can Guo <can.guo@oss.qualcomm.com>
Reviewed-by: Peter Wang <peter.wang@mediatek.com>
Link: https://patch.msgid.link/20260325152154.1604082-2-can.guo@oss.qualcomm.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 10 insertions, 7 deletions

diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h
index 8563b6648976..51c2555bea73 100644
--- a/include/ufs/ufshcd.h
+++ b/include/ufs/ufshcd.h
@@ -302,11 +302,10 @@ struct ufs_pwr_mode_info {
  *                     variant specific Uni-Pro initialization.
  * @link_startup_notify: called before and after Link startup is carried out
  *                       to allow variant specific Uni-Pro initialization.
+ * @negotiate_pwr_mode: called to negotiate power mode.
  * @pwr_change_notify: called before and after a power mode change
  *			is carried out to allow vendor spesific capabilities
- *			to be set. PRE_CHANGE can modify final_params based
- *			on desired_pwr_mode, but POST_CHANGE must not alter
- *			the final_params parameter
+ *			to be set.
  * @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
@@ -347,10 +346,12 @@ struct ufs_hba_variant_ops {
 				     enum ufs_notify_change_status);
 	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,
-			const struct ufs_pa_layer_attr *desired_pwr_mode,
-			struct ufs_pa_layer_attr *final_params);
+	int	(*negotiate_pwr_mode)(struct ufs_hba *hba,
+				      const struct ufs_pa_layer_attr *desired_pwr_mode,
+				      struct ufs_pa_layer_attr *final_params);
+	int	(*pwr_change_notify)(struct ufs_hba *hba,
+				     enum ufs_notify_change_status status,
+				     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);
@@ -1361,6 +1362,8 @@ extern int ufshcd_dme_set_attr(struct ufs_hba *hba, u32 attr_sel,
 			       u8 attr_set, u32 mib_val, u8 peer);
 extern int ufshcd_dme_get_attr(struct ufs_hba *hba, u32 attr_sel,
 			       u32 *mib_val, u8 peer);
+extern int ufshcd_change_power_mode(struct ufs_hba *hba,
+				    struct ufs_pa_layer_attr *pwr_mode);
 extern int ufshcd_config_pwr_mode(struct ufs_hba *hba,
 			struct ufs_pa_layer_attr *desired_pwr_mode);
 extern int ufshcd_uic_change_pwr_mode(struct ufs_hba *hba, u8 mode);