MIPS: Add implementation of dma_map_ops.mmap()
The generic implementation of dma_map_ops.mmap(), dma_common_mmap(), is not correct for non-coherent devices. It expects to be passed a virtual address previously returned by dma_alloc_coherent(), which for a non-coherent device will return a KSEG1 address. It then attempts to convert that virtual address to a physical address using virt_to_page() which will yield an incorrect address. Also, dma_common_mmap() does not handle the DMA_ATTR_WRITE_COMBINE attribute, and therefore dma_mmap_writecombine() will not actually set the appropriate pgprot_t flags for write combining. This patch adds an implementation of dma_map_ops.mmap() that correctly handles KSEG1 addresses, and enables write combining when requested. Signed-off-by: Alex Smith <alex.smith@imgtec.com> Cc: Sadegh Abbasi <Sadegh.Abbasi@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/10808/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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