RE: [PATCH v2 14/19] scsi: ufs: Use the doorbell register instead of the UTRLCNR register

[Avri Altman <Avri.Altman@xxxxxxx>]

Using the UTRLCNR register implies performing two MMIO accesses in the hot path while reading the doorbell register only involves a single MMIO operation. Hence do not use the UTRLNCR register.

Isn't this patch, and the one before, practically reverting
6f7151729647 (scsi: ufs: Utilize Transfer Request List Completion Notification Register)?
Wouldn't it be simpler then just revert it in #13, and add whatever is needed in #14?

Thanks,
Avri

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Stanley Chu <stanley.chu@xxxxxxxxxxxx>
Cc: Can Guo <cang@xxxxxxxxxxxxxx>
Cc: Asutosh Das <asutoshd@xxxxxxxxxxxxxx>
Cc: Avri Altman <avri.altman@xxxxxxx>
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
 drivers/scsi/ufs/ufshcd.c | 2 +-
 drivers/scsi/ufs/ufshcd.h | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 996b95ab74aa..becd9e2829f4 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6388,7 +6388,7 @@ static irqreturn_t ufshcd_sl_intr(struct ufs_hba *hba, u32 intr_status)
                retval |= ufshcd_tmc_handler(hba);

        if (intr_status & UTP_TRANSFER_REQ_COMPL)
-               retval |= ufshcd_trc_handler(hba, ufshcd_has_utrlcnr(hba));
+               retval |= ufshcd_trc_handler(hba, 
+ ufshcd_use_utrlcnr(hba));

        return retval;
 }
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h index f8766e8f3cac..b3d9b487846f 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -1184,9 +1184,9 @@ static inline u32 ufshcd_vops_get_ufs_hci_version(struct ufs_hba *hba)
        return ufshcd_readl(hba, REG_UFS_VERSION);  }

-static inline bool ufshcd_has_utrlcnr(struct ufs_hba *hba)
+static inline bool ufshcd_use_utrlcnr(struct ufs_hba *hba)
 {
-       return (hba->ufs_version >= ufshci_version(3, 0));
+       return false;
 }

 static inline int ufshcd_vops_clk_scale_notify(struct ufs_hba *hba,