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authorChristoph Hellwig <hch@lst.de>2022-10-04 09:10:19 +0200
committerChristoph Hellwig <hch@lst.de>2022-10-06 14:30:51 +0200
commit49bc8bebae79c8516cb12f91818f3a7907e3ebce (patch)
treed574a81615e2932c54ff2287b7a459c583d7f4c1 /arch
parentf7f04d198334d6f69c76c8f8675194551a3da574 (diff)
ARM/dma-mappіng: don't override ->dma_coherent when set from a bus notifier
Commit ae626eb97376 ("ARM/dma-mapping: use dma-direct unconditionally") caused a regression on the mvebu platform, wherein devices that are dma-coherent are marked as dma-noncoherent, because although mvebu_hwcc_notifier() after that commit still marks then as coherent, the arm_coherent_dma_ops() function, which is called later, overwrites this setting, since it is being called from drivers/of/device.c with coherency parameter determined by of_dma_is_coherent(), and the device-trees do not declare the 'dma-coherent' property. Fix this by defaulting never clearing the dma_coherent flag in arm_coherent_dma_ops(). Fixes: ae626eb97376 ("ARM/dma-mapping: use dma-direct unconditionally") Reported-by: Marek Behún <kabel@kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Tested-by: Marek Behún <kabel@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/mm/dma-mapping.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 089c9c644cce..bfc7476f1411 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1769,8 +1769,16 @@ static void arm_teardown_iommu_dma_ops(struct device *dev) { }
void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
const struct iommu_ops *iommu, bool coherent)
{
- dev->archdata.dma_coherent = coherent;
- dev->dma_coherent = coherent;
+ /*
+ * Due to legacy code that sets the ->dma_coherent flag from a bus
+ * notifier we can't just assign coherent to the ->dma_coherent flag
+ * here, but instead have to make sure we only set but never clear it
+ * for now.
+ */
+ if (coherent) {
+ dev->archdata.dma_coherent = true;
+ dev->dma_coherent = true;
+ }
/*
* Don't override the dma_ops if they have already been set. Ideally