From cf65a0f6f6ff7631ba0ac0513a14ca5b65320d80 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 12 Jun 2018 19:01:45 +0200 Subject: dma-mapping: move all DMA mapping code to kernel/dma Currently the code is split over various files with dma- prefixes in the lib/ and drives/base directories, and the number of files keeps growing. Move them into a single directory to keep the code together and remove the file name prefixes. To match the irq infrastructure this directory is placed under the kernel/ directory. Signed-off-by: Christoph Hellwig --- kernel/dma/virt.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) create mode 100644 kernel/dma/virt.c (limited to 'kernel/dma/virt.c') diff --git a/kernel/dma/virt.c b/kernel/dma/virt.c new file mode 100644 index 000000000000..631ddec4b60a --- /dev/null +++ b/kernel/dma/virt.c @@ -0,0 +1,59 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * DMA operations that map to virtual addresses without flushing memory. + */ +#include +#include +#include +#include + +static void *dma_virt_alloc(struct device *dev, size_t size, + dma_addr_t *dma_handle, gfp_t gfp, + unsigned long attrs) +{ + void *ret; + + ret = (void *)__get_free_pages(gfp, get_order(size)); + if (ret) + *dma_handle = (uintptr_t)ret; + return ret; +} + +static void dma_virt_free(struct device *dev, size_t size, + void *cpu_addr, dma_addr_t dma_addr, + unsigned long attrs) +{ + free_pages((unsigned long)cpu_addr, get_order(size)); +} + +static dma_addr_t dma_virt_map_page(struct device *dev, struct page *page, + unsigned long offset, size_t size, + enum dma_data_direction dir, + unsigned long attrs) +{ + return (uintptr_t)(page_address(page) + offset); +} + +static int dma_virt_map_sg(struct device *dev, struct scatterlist *sgl, + int nents, enum dma_data_direction dir, + unsigned long attrs) +{ + int i; + struct scatterlist *sg; + + for_each_sg(sgl, sg, nents, i) { + BUG_ON(!sg_page(sg)); + sg_dma_address(sg) = (uintptr_t)sg_virt(sg); + sg_dma_len(sg) = sg->length; + } + + return nents; +} + +const struct dma_map_ops dma_virt_ops = { + .alloc = dma_virt_alloc, + .free = dma_virt_free, + .map_page = dma_virt_map_page, + .map_sg = dma_virt_map_sg, +}; +EXPORT_SYMBOL(dma_virt_ops); -- cgit v1.2.3