From 1a9777a8a01fb88659a3dda48080c95c34cab7d3 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Sun, 24 Dec 2017 15:04:32 +0100 Subject: dma-direct: reject too small dma masks Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy --- lib/dma-direct.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'lib/dma-direct.c') 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); -- cgit v1.2.3-59-g8ed1b