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authorChristoph Hellwig <hch@lst.de>2018-04-27 09:02:55 +0200
committerChristoph Hellwig <hch@lst.de>2018-05-28 12:46:54 +0200
commitf068fe3170bcf06f14fd0a9eec0be12be04ff012 (patch)
treebc3e751c6a163515ada11ccd4e08465413c63b71 /lib
parent884571f0de7b02bb784be3a5c870eabce62cdaeb (diff)
core, dma-direct: add a flag 32-bit dma limits
Various PCI bridges (VIA PCI, Xilinx PCIe) limit DMA to only 32-bits even if the device itself supports more. Add a single bit flag to struct device (to be moved into the dma extension once we get to it) to flag such devices and reject larger DMA to them. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/dma-direct.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/lib/dma-direct.c b/lib/dma-direct.c
index b824eb218782..a48f94eff62e 100644
--- a/lib/dma-direct.c
+++ b/lib/dma-direct.c
@@ -172,6 +172,12 @@ int dma_direct_supported(struct device *dev, u64 mask)
if (mask < DMA_BIT_MASK(32))
return 0;
#endif
+ /*
+ * Various PCI/PCIe bridges have broken support for > 32bit DMA even
+ * if the device itself might support it.
+ */
+ if (dev->dma_32bit_limit && mask > DMA_BIT_MASK(32))
+ return 0;
return 1;
}