diff options
| author |   Christoph Hellwig <hch@lst.de> | 2017-12-24 15:04:32 +0100 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2018-01-15 09:35:15 +0100 |
| commit | 1a9777a8a01fb88659a3dda48080c95c34cab7d3 (patch) | |
| tree | 8dbc7851ef09db41b5e2f0bed1bd5fff84c5a240 /lib | |
| parent | dma-direct: make dma_direct_{alloc,free} available to other implementations (diff) | |
| download | linux-dev-1a9777a8a01fb88659a3dda48080c95c34cab7d3.tar.xz linux-dev-1a9777a8a01fb88659a3dda48080c95c34cab7d3.zip | |
dma-direct: reject too small dma masks
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/dma-direct.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/lib/dma-direct.c b/lib/dma-direct.c index 784a68dfdbe3..40b1f92f2214 100644 --- a/lib/dma-direct.c +++ b/lib/dma-direct.c @@ -122,6 +122,24 @@ static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, return nents; } +int dma_direct_supported(struct device *dev, u64 mask) +{ +#ifdef CONFIG_ZONE_DMA + if (mask < DMA_BIT_MASK(ARCH_ZONE_DMA_BITS)) + return 0; +#else + /* + * Because 32-bit DMA masks are so common we expect every architecture + * to be able to satisfy them - either by not supporting more physical + * memory, or by providing a ZONE_DMA32. If neither is the case, the + * architecture needs to use an IOMMU instead of the direct mapping. + */ + if (mask < DMA_BIT_MASK(32)) + return 0; +#endif + return 1; +} + static int dma_direct_mapping_error(struct device *dev, dma_addr_t dma_addr) { return dma_addr == DIRECT_MAPPING_ERROR; @@ -132,6 +150,7 @@ const struct dma_map_ops dma_direct_ops = { .free = dma_direct_free, .map_page = dma_direct_map_page, .map_sg = dma_direct_map_sg, + .dma_supported = dma_direct_supported, .mapping_error = dma_direct_mapping_error, }; EXPORT_SYMBOL(dma_direct_ops); |