From 002e67454f61bb67d8071ac4d0cacb86a01d18e0 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 9 Jan 2018 16:30:23 +0100 Subject: dma-direct: rename dma_noop to dma_direct The trivial direct mapping implementation already does a virtual to physical translation which isn't strictly a noop, and will soon learn to do non-direct but linear physical to dma translations through the device offset and a few small tricks. Rename it to a better fitting name. Signed-off-by: Christoph Hellwig Reviewed-by: Vladimir Murzin --- lib/dma-direct.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 lib/dma-direct.c (limited to 'lib/dma-direct.c') diff --git a/lib/dma-direct.c b/lib/dma-direct.c new file mode 100644 index 0000000..0ec3262 --- /dev/null +++ b/lib/dma-direct.c @@ -0,0 +1,63 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * lib/dma-noop.c + * + * DMA operations that map to physical addresses without flushing memory. + */ +#include +#include +#include +#include +#include + +static void *dma_direct_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 = virt_to_phys(ret) - PFN_PHYS(dev->dma_pfn_offset); + + return ret; +} + +static void dma_direct_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_direct_map_page(struct device *dev, struct page *page, + unsigned long offset, size_t size, enum dma_data_direction dir, + unsigned long attrs) +{ + return page_to_phys(page) + offset - PFN_PHYS(dev->dma_pfn_offset); +} + +static int dma_direct_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) { + dma_addr_t offset = PFN_PHYS(dev->dma_pfn_offset); + void *va; + + BUG_ON(!sg_page(sg)); + va = sg_virt(sg); + sg_dma_address(sg) = (dma_addr_t)virt_to_phys(va) - offset; + sg_dma_len(sg) = sg->length; + } + + return nents; +} + +const struct dma_map_ops dma_direct_ops = { + .alloc = dma_direct_alloc, + .free = dma_direct_free, + .map_page = dma_direct_map_page, + .map_sg = dma_direct_map_sg, +}; +EXPORT_SYMBOL(dma_direct_ops); -- cgit v1.1