Andrew Halaney 872f68019b scsi: ufs: cdns-pltfrm: Perform read back after writing HCLKDIV ... [ Upstream commit b715c55daf ] Currently, HCLKDIV is 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 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 mb()'s purpose wasn't to add extra ordering (on top of the ordering guaranteed by writel()/readl()), it can safely be removed. Fixes: d90996dae8 ("scsi: ufs: Add UFS platform driver for Cadence UFS") 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-v5-6-181252004586@redhat.com Reviewed-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>		2024-06-12 11:11:39 +02:00
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cdns-pltfrm.c	scsi: ufs: cdns-pltfrm: Perform read back after writing HCLKDIV	2024-06-12 11:11:39 +02:00
Kconfig
Makefile
tc-dwc-g210-pci.c
tc-dwc-g210-pltfrm.c
tc-dwc-g210.c
tc-dwc-g210.h
ti-j721e-ufs.c
ufs-exynos.c
ufs-exynos.h
ufs-hisi.c
ufs-hisi.h
ufs-mediatek-trace.h
ufs-mediatek.c
ufs-mediatek.h
ufs-qcom.c	scsi: ufs: qcom: Perform read back after writing CGC enable	2024-06-12 11:11:39 +02:00
ufs-qcom.h	scsi: ufs: qcom: Perform read back after writing reset bit	2024-06-12 11:11:39 +02:00
ufs-renesas.c
ufs-sprd.c
ufs-sprd.h
ufshcd-dwc.c
ufshcd-dwc.h
ufshcd-pci.c
ufshcd-pltfrm.c
ufshcd-pltfrm.h
ufshci-dwc.h