scsi: ufs: introduce the capability and quirk for interrupt aggregation

UFS HCI (Host Controller Interface) allows the transfer requests
interrupts to be aggregated to generate the single interrupt but
this can impact the performance. Hence introduce the capability which
gives choice to use the interrupt aggregation capability or not.
By default interrupt aggregation capability is kept disabled.

This change also introduces a quirk for broken interrupt aggregation
feature, as in some UFS controllers, this feature may not work.

Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>
Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>

1 files changed, 16 insertions, 3 deletions

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 648a44675880..9641bcb90cd2 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -481,6 +481,15 @@ ufshcd_config_intr_aggr(struct ufs_hba *hba, u8 cnt, u8 tmout)
 }
 
 /**
+ * ufshcd_disable_intr_aggr - Disables interrupt aggregation.
+ * @hba: per adapter instance
+ */
+static inline void ufshcd_disable_intr_aggr(struct ufs_hba *hba)
+{
+	ufshcd_writel(hba, 0, REG_UTP_TRANSFER_REQ_INT_AGG_CONTROL);
+}
+
+/**
  * ufshcd_enable_run_stop_reg - Enable run-stop registers,
  *			When run-stop registers are set to 1, it indicates the
  *			host controller that it can process the requests
@@ -1326,7 +1335,7 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
 	lrbp->sense_buffer = cmd->sense_buffer;
 	lrbp->task_tag = tag;
 	lrbp->lun = ufshcd_scsi_to_upiu_lun(cmd->device->lun);
-	lrbp->intr_cmd = false;
+	lrbp->intr_cmd = !ufshcd_is_intr_aggr_allowed(hba) ? true : false;
 	lrbp->command_type = UTP_CMD_TYPE_SCSI;
 
 	/* form UPIU before issuing the command */
@@ -2522,7 +2531,10 @@ static int ufshcd_make_hba_operational(struct ufs_hba *hba)
 	ufshcd_enable_intr(hba, UFSHCD_ENABLE_INTRS);
 
 	/* Configure interrupt aggregation */
-	ufshcd_config_intr_aggr(hba, hba->nutrs - 1, INT_AGGR_DEF_TO);
+	if (ufshcd_is_intr_aggr_allowed(hba))
+		ufshcd_config_intr_aggr(hba, hba->nutrs - 1, INT_AGGR_DEF_TO);
+	else
+		ufshcd_disable_intr_aggr(hba);
 
 	/* Configure UTRL and UTMRL base address registers */
 	ufshcd_writel(hba, lower_32_bits(hba->utrdl_dma_addr),
@@ -3073,7 +3085,8 @@ static void ufshcd_transfer_req_compl(struct ufs_hba *hba)
 	 * false interrupt if device completes another request after resetting
 	 * aggregation and before reading the DB.
 	 */
-	ufshcd_reset_intr_aggr(hba);
+	if (ufshcd_is_intr_aggr_allowed(hba))
+		ufshcd_reset_intr_aggr(hba);
 
 	tr_doorbell = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
 	completed_reqs = tr_doorbell ^ hba->outstanding_reqs;