Andrew Halaney 4bf3855497 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>
2024-04-05 21:06:29 -04:00
..
2024-03-13 18:34:05 -07:00
2024-03-21 13:34:15 -07:00
2024-03-22 12:46:07 -07:00
2024-03-19 11:57:26 -07:00
2024-03-18 15:11:44 -07:00
2024-03-15 11:58:32 -07:00
2024-03-15 12:25:13 -07:00
2024-03-24 13:54:06 -07:00
2024-03-21 19:04:31 -07:00
2024-03-14 09:56:15 -07:00
2024-03-21 10:01:02 -07:00
2024-03-18 15:34:03 -07:00
2024-03-24 10:45:31 -07:00
2024-03-15 17:53:48 -07:00
2024-03-18 17:30:46 +00:00
2024-03-13 10:59:28 -07:00
2024-03-21 12:44:10 -07:00
2024-03-23 08:43:21 -07:00
2024-03-18 17:30:46 +00:00
2024-03-23 08:43:21 -07:00
2024-03-15 11:58:32 -07:00
2024-03-21 13:23:07 -06:00
2024-03-21 13:34:15 -07:00
2024-03-14 10:58:27 -07:00
2024-03-21 12:35:20 -07:00
2024-03-16 11:24:51 -07:00
2024-03-13 11:33:10 -07:00
2024-03-12 17:44:08 -07:00
2024-03-22 09:52:37 -07:00
2024-03-21 10:37:39 -07:00
2024-03-21 17:16:46 -07:00
2024-03-22 13:31:07 -07:00
2024-03-21 15:18:18 -07:00
2024-03-15 12:22:52 -07:00
2024-03-22 09:57:00 -07:00
2024-03-16 16:31:12 -07:00
2024-03-12 10:35:24 -07:00
2024-03-21 12:44:10 -07:00
2024-03-21 12:35:20 -07:00
2024-03-15 13:21:13 -07:00
2024-03-19 08:57:39 -07:00
2024-03-17 12:06:10 -07:00
2024-03-19 08:48:09 -07:00