Christoph Hellwig | 002e674 | 2018-01-09 16:30:23 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
Christoph Hellwig | 2e86a04 | 2017-12-22 11:29:51 +0100 | [diff] [blame^] | 3 | * DMA operations that map physical memory directly without using an IOMMU or |
| 4 | * flushing caches. |
Christoph Hellwig | 002e674 | 2018-01-09 16:30:23 +0100 | [diff] [blame] | 5 | */ |
| 6 | #include <linux/export.h> |
| 7 | #include <linux/mm.h> |
Christoph Hellwig | 2e86a04 | 2017-12-22 11:29:51 +0100 | [diff] [blame^] | 8 | #include <linux/dma-direct.h> |
Christoph Hellwig | 002e674 | 2018-01-09 16:30:23 +0100 | [diff] [blame] | 9 | #include <linux/scatterlist.h> |
| 10 | #include <linux/pfn.h> |
| 11 | |
| 12 | static void *dma_direct_alloc(struct device *dev, size_t size, |
| 13 | dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs) |
| 14 | { |
| 15 | void *ret; |
| 16 | |
| 17 | ret = (void *)__get_free_pages(gfp, get_order(size)); |
| 18 | if (ret) |
Christoph Hellwig | 2e86a04 | 2017-12-22 11:29:51 +0100 | [diff] [blame^] | 19 | *dma_handle = phys_to_dma(dev, virt_to_phys(ret)); |
Christoph Hellwig | 002e674 | 2018-01-09 16:30:23 +0100 | [diff] [blame] | 20 | |
| 21 | return ret; |
| 22 | } |
| 23 | |
| 24 | static void dma_direct_free(struct device *dev, size_t size, void *cpu_addr, |
| 25 | dma_addr_t dma_addr, unsigned long attrs) |
| 26 | { |
| 27 | free_pages((unsigned long)cpu_addr, get_order(size)); |
| 28 | } |
| 29 | |
| 30 | static dma_addr_t dma_direct_map_page(struct device *dev, struct page *page, |
| 31 | unsigned long offset, size_t size, enum dma_data_direction dir, |
| 32 | unsigned long attrs) |
| 33 | { |
Christoph Hellwig | 2e86a04 | 2017-12-22 11:29:51 +0100 | [diff] [blame^] | 34 | return phys_to_dma(dev, page_to_phys(page)) + offset; |
Christoph Hellwig | 002e674 | 2018-01-09 16:30:23 +0100 | [diff] [blame] | 35 | } |
| 36 | |
| 37 | static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, |
| 38 | int nents, enum dma_data_direction dir, unsigned long attrs) |
| 39 | { |
| 40 | int i; |
| 41 | struct scatterlist *sg; |
| 42 | |
| 43 | for_each_sg(sgl, sg, nents, i) { |
Christoph Hellwig | 002e674 | 2018-01-09 16:30:23 +0100 | [diff] [blame] | 44 | BUG_ON(!sg_page(sg)); |
Christoph Hellwig | 2e86a04 | 2017-12-22 11:29:51 +0100 | [diff] [blame^] | 45 | |
| 46 | sg_dma_address(sg) = phys_to_dma(dev, sg_phys(sg)); |
Christoph Hellwig | 002e674 | 2018-01-09 16:30:23 +0100 | [diff] [blame] | 47 | sg_dma_len(sg) = sg->length; |
| 48 | } |
| 49 | |
| 50 | return nents; |
| 51 | } |
| 52 | |
| 53 | const struct dma_map_ops dma_direct_ops = { |
| 54 | .alloc = dma_direct_alloc, |
| 55 | .free = dma_direct_free, |
| 56 | .map_page = dma_direct_map_page, |
| 57 | .map_sg = dma_direct_map_sg, |
| 58 | }; |
| 59 | EXPORT_SYMBOL(dma_direct_ops); |