diff options
| author | Andrew Halaney <ahalaney@redhat.com> | 2024-03-29 15:46:51 -0500 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2024-04-05 21:06:29 -0400 |
| commit | 4bf3855497b60765ca03b983d064b25e99b97657 (patch) | |
| tree | c8a9fb16dcb4576bf95e9478dda1b84f678fe54c /drivers/ufs/core/ufshcd.c | |
| parent | e4a628877119bd40164a651d20321247b6f94a8b (diff) | |
scsi: ufs: core: Perform read back after disabling UIC_COMMAND_COMPL
Currently, the UIC_COMMAND_COMPL interrupt is disabled and a wmb() is used
to complete the register write before any following writes.
wmb() ensures the writes complete in that order, but completion doesn't
mean that it isn't stored in a buffer somewhere. The recommendation for
ensuring this bit has taken effect on the device is to perform a read back
to force it to make it all the way to the device. This is documented in
device-io.rst and a talk by Will Deacon on this can be seen over here:
https://youtu.be/i6DayghhA8Q?si=MiyxB5cKJXSaoc01&t=1678
Let's do that to ensure the bit hits the device. Because the wmb()'s
purpose wasn't to add extra ordering (on top of the ordering guaranteed by
writel()/readl()), it can safely be removed.
Fixes: d75f7fe495cf ("scsi: ufs: reduce the interrupts for power mode change requests")
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Can Guo <quic_cang@quicinc.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Andrew Halaney <ahalaney@redhat.com>
Link: https://lore.kernel.org/r/20240329-ufs-reset-ensure-effect-before-delay-v5-9-181252004586@redhat.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/ufs/core/ufshcd.c')
| -rw-r--r-- | drivers/ufs/core/ufshcd.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index 268fcfebd7bd..dfa4f827766a 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -4287,7 +4287,7 @@ static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd) * Make sure UIC command completion interrupt is disabled before * issuing UIC command. */ - wmb(); + ufshcd_readl(hba, REG_INTERRUPT_ENABLE); reenable_intr = true; } spin_unlock_irqrestore(hba->host->host_lock, flags); |