korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-15 00:04:15 +08:00
Code Issues Packages Projects Releases Wiki Activity

scsi: ufs: core: Perform read back after disabling UIC_COMMAND_COMPL

Browse Source 
[ Upstream commit 4bf3855497 ]

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: d75f7fe495 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Andrew Halaney 2024-03-29 15:46:51 -05:00 committed by Greg Kroah-Hartman
parent bf144a2e3b
commit 8dfd79c1c3
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/scsi/ufs/ufshcd.c
View File

@ -3754,7 +3754,7 @@ 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;
}
ret = __ufshcd_send_uic_cmd(hba, cmd, false);