From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: [PATCH 33/67] dma-direct: reject too small dma masks Date: Fri, 29 Dec 2017 09:18:37 +0100 Message-ID: <20171229081911.2802-34-hch__689.398896838789$1514535610$gmane$org@lst.de> References: <20171229081911.2802-1-hch@lst.de> Return-path: In-Reply-To: <20171229081911.2802-1-hch@lst.de> Sender: linux-m68k-owner@vger.kernel.org List-Id: linux-m68k@vger.kernel.org To: iommu@lists.linux-foundation.org Cc: linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, adi-buildroot-devel@lists.sourceforge.net, linux-c6x-dev@linux-c6x.org, linux-cris-kernel@axis.com, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-metag@vger.kernel.org, Michal Simek , linux-mips@linux-mips.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, patches@groups.riscv.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, Guan Xuetao , x86@kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Signed-off-by: Christoph Hellwig --- include/linux/dma-direct.h | 1 + lib/dma-direct.c | 19 +++++++++++++++++++ 2 files changed, 20 insertions(+) diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h index 4788bf0bf683..bcdb1a3e4b1f 100644 --- a/include/linux/dma-direct.h +++ b/include/linux/dma-direct.h @@ -42,5 +42,6 @@ void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs); void dma_direct_free(struct device *dev, size_t size, void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs); +int dma_direct_supported(struct device *dev, u64 mask); #endif /* _LINUX_DMA_DIRECT_H */ diff --git a/lib/dma-direct.c b/lib/dma-direct.c index 2e9b9494610c..5bb289483efc 100644 --- a/lib/dma-direct.c +++ b/lib/dma-direct.c @@ -123,6 +123,24 @@ 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; @@ -133,6 +151,7 @@ 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, .is_phys = true, }; -- 2.14.2