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| author | Andrew Halaney <ahalaney@redhat.com> | 2024-03-29 23:46:49 +0300 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2024-04-06 04:06:29 +0300 |
| commit | 408e28086f1c7a6423efc79926a43d7001902fae (patch) | |
| tree | 12a9c98ced963ce98502cd592915650b138a85f6 /drivers/ufs/core | |
| parent | b715c55daf598aac8fa339048e4ca8a0916b332e (diff) | |
| download | linux-408e28086f1c7a6423efc79926a43d7001902fae.tar.xz | |
scsi: ufs: core: Perform read back after writing UTP_TASK_REQ_LIST_BASE_H
Currently, the UTP_TASK_REQ_LIST_BASE_L/UTP_TASK_REQ_LIST_BASE_H regs are
written to and then completed with an mb().
mb() ensures that the write completes, but completion doesn't mean that it
isn't stored in a buffer somewhere. The recommendation for ensuring these
bits have 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 bits hit the device. Because the mb()'s purpose
wasn't to add extra ordering (on top of the ordering guaranteed by
writel()/readl()), it can safely be removed.
Fixes: 88441a8d355d ("scsi: ufs: core: Add hibernation callbacks")
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Can Guo <quic_cang@quicinc.com>
Signed-off-by: Andrew Halaney <ahalaney@redhat.com>
Link: https://lore.kernel.org/r/20240329-ufs-reset-ensure-effect-before-delay-v5-7-181252004586@redhat.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/ufs/core')
| -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 e30fd125988d..a89887878d98 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -10395,7 +10395,7 @@ int ufshcd_system_restore(struct device *dev) * are updated with the latest queue addresses. Only after * updating these addresses, we can queue the new commands. */ - mb(); + ufshcd_readl(hba, REG_UTP_TASK_REQ_LIST_BASE_H); /* Resuming from hibernate, assume that link was OFF */ ufshcd_set_link_off(hba); |