[PATCH AUTOSEL 5.15 13/41] scsi: ufs: Support clearing multiple commands at once

Sasha Levin
2022-06-28T02:23:20Z

From: Bart Van Assche <bvanassche@acm.org>

[ Upstream commit d1a7644648b7cdacaf8d1013a4285001911e9bc8 ]

Modify ufshcd_clear_cmd() such that it supports clearing multiple commands
at once instead of one command at a time. This change will be used in a
later patch to reduce the time spent in the reset handler.

Link: https://lore.kernel.org/r/20220613214442.212466-3-bvanassche@acm.org
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/ufs/ufshcd.c | 42 ++++++++++++++++++++++++++-------------
1 file changed, 28 insertions(+), 14 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 311170e63410..b5684bd32621 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -727,17 +727,28 @@ static inline int ufshcd_get_tr_ocs(struct ufshcd_lrb *lrbp)
}

/**
- * ufshcd_utrl_clear - Clear a bit in UTRLCLR register
+ * ufshcd_utrl_clear() - Clear requests from the controller request list.
* @hba: per adapter instance
- * @pos: position of the bit to be cleared
+ * @mask: mask with one bit set for each request to be cleared
*/
-static inline void ufshcd_utrl_clear(struct ufs_hba *hba, u32 pos)
+static inline void ufshcd_utrl_clear(struct ufs_hba *hba, u32 mask)
{
if (hba->quirks & UFSHCI_QUIRK_BROKEN_REQ_LIST_CLR)
- ufshcd_writel(hba, (1 << pos), REG_UTP_TRANSFER_REQ_LIST_CLEAR);
- else
- ufshcd_writel(hba, ~(1 << pos),
- REG_UTP_TRANSFER_REQ_LIST_CLEAR);
+ mask = ~mask;
+ /*
+ * From the UFSHCI specification: "UTP Transfer Request List CLear
+ * Register (UTRLCLR): This field is bit significant. Each bit
+ * corresponds to a slot in the UTP Transfer Request List, where bit 0
+ * corresponds to request slot 0. A bit in this field is set to ‘0’
+ * by host software to indicate to the host controller that a transfer
+ * request slot is cleared. The host controller
+ * shall free up any resources associated to the request slot
+ * immediately, and shall set the associated bit in UTRLDBR to ‘0’. The
+ * host software indicates no change to request slots by setting the
+ * associated bits in this field to ‘1’. Bits in this field shall only
+ * be set ‘1’ or ‘0’ by host software when UTRLRSR is set to ‘1’."
+ */
+ ufshcd_writel(hba, ~mask, REG_UTP_TRANSFER_REQ_LIST_CLEAR);
}

/**
@@ -2795,15 +2806,18 @@ static int ufshcd_compose_dev_cmd(struct ufs_hba *hba,
return ufshcd_compose_devman_upiu(hba, lrbp);
}

-static int
-ufshcd_clear_cmd(struct ufs_hba *hba, int tag)
+/*
+ * Clear all the requests from the controller for which a bit has been set in
+ * @mask and wait until the controller confirms that these requests have been
+ * cleared.
+ */
+static int ufshcd_clear_cmds(struct ufs_hba *hba, u32 mask)
{
unsigned long flags;
- u32 mask = 1 << tag;

/* clear outstanding transaction before retry */
spin_lock_irqsave(hba->host->host_lock, flags);
- ufshcd_utrl_clear(hba, tag);
+ ufshcd_utrl_clear(hba, mask);
spin_unlock_irqrestore(hba->host->host_lock, flags);

/*
@@ -2891,7 +2905,7 @@ static int ufshcd_wait_for_dev_cmd(struct ufs_hba *hba,
err = -ETIMEDOUT;
dev_dbg(hba->dev, "%s: dev_cmd request timedout, tag %d\n",
__func__, lrbp->task_tag);
- if (!ufshcd_clear_cmd(hba, lrbp->task_tag))
+ if (!ufshcd_clear_cmds(hba, 1U << lrbp->task_tag))
/* successfully cleared the command, retry if needed */
err = -EAGAIN;
/*
@@ -6820,7 +6834,7 @@ static int ufshcd_eh_device_reset_handler(struct scsi_cmnd *cmd)
/* clear the commands that were pending for corresponding LUN */
for_each_set_bit(pos, &hba->outstanding_reqs, hba->nutrs) {
if (hba->lrb[pos].lun == lun) {
- err = ufshcd_clear_cmd(hba, pos);
+ err = ufshcd_clear_cmds(hba, 1U << pos);
if (err)
break;
__ufshcd_transfer_req_compl(hba, 1U << pos, false);
@@ -6922,7 +6936,7 @@ static int ufshcd_try_to_abort_task(struct ufs_hba *hba, int tag)
goto out;
}

- err = ufshcd_clear_cmd(hba, tag);
+ err = ufshcd_clear_cmds(hba, 1U << tag);
if (err)
dev_err(hba->dev, "%s: Failed clearing cmd at tag %d, err %d\n",
__func__, tag, err);
--
2.35.1