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| author | Christoph Hellwig <hch@lst.de> | 2018-04-27 09:02:55 +0200 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2018-05-28 12:46:54 +0200 |
| commit | f068fe3170bcf06f14fd0a9eec0be12be04ff012 (patch) | |
| tree | bc3e751c6a163515ada11ccd4e08465413c63b71 | |
| parent | dma-mapping: remove unused gfp_t parameter to arch_dma_alloc_attrs (diff) | |
| download | linux-f068fe3170bcf06f14fd0a9eec0be12be04ff012.tar.xz linux-f068fe3170bcf06f14fd0a9eec0be12be04ff012.zip | |
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>
| -rw-r--r-- | include/linux/device.h | 3 | ||||
| -rw-r--r-- | lib/dma-direct.c | 6 |
2 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/device.h b/include/linux/device.h index 563077d1cdc1..00b6c3b42437 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -904,6 +904,8 @@ struct dev_links_info { * @offline: Set after successful invocation of bus type's .offline(). * @of_node_reused: Set if the device-tree node is shared with an ancestor * device. + * @dma_32bit_limit: bridge limited to 32bit DMA even if the device itself + * indicates support for a higher limit in the dma_mask field. * * At the lowest level, every device in a Linux system is represented by an * instance of struct device. The device structure contains the information @@ -992,6 +994,7 @@ struct device { bool offline_disabled:1; bool offline:1; bool of_node_reused:1; + bool dma_32bit_limit:1; }; static inline struct device *kobj_to_dev(struct kobject *kobj) 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; } |