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| author | Andrew Halaney <ahalaney@redhat.com> | 2024-03-29 23:46:50 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-05-30 10:49:09 +0300 |
| commit | 7a9f32167347f3f89f7b6ef1c434e7919342aeb9 (patch) | |
| tree | ea3ba15e8924242731b17dc855df938715dc0891 /drivers/ufs | |
| parent | 8950ea401a8961a741668dcd5667c3707356ed92 (diff) | |
| download | linux-7a9f32167347f3f89f7b6ef1c434e7919342aeb9.tar.xz | |
scsi: ufs: core: Perform read back after disabling interrupts
[ Upstream commit e4a628877119bd40164a651d20321247b6f94a8b ]
Currently, interrupts are cleared and disabled prior to registering the
interrupt. An mb() is used to complete the clear/disable writes before the
interrupt is registered.
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 these 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: 199ef13cac7d ("scsi: ufs: avoid spurious UFS host controller interrupts")
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-v5-8-181252004586@redhat.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/ufs')
| -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 16dc63632e72..33068bbfa7a3 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -10570,7 +10570,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq) * Make sure that UFS interrupts are disabled and any pending interrupt * status is cleared before registering UFS interrupt handler. */ - mb(); + ufshcd_readl(hba, REG_INTERRUPT_ENABLE); /* IRQ registration */ err = devm_request_irq(dev, irq, ufshcd_intr, IRQF_SHARED, UFSHCD, hba); |