| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | #ifndef _ASM_SCATTERLIST_H |
| 2 | #define _ASM_SCATTERLIST_H |
| 3 | |
| 4 | /* |
| 5 | * Drivers must set either ->address or (preferred) ->page and ->offset |
| 6 | * to indicate where data must be transferred to/from. |
| 7 | * |
| 8 | * Using ->page is recommended since it handles highmem data as well as |
| 9 | * low mem. ->address is restricted to data which has a virtual mapping, and |
| 10 | * it will go away in the future. Updating to ->page can be automated very |
| 11 | * easily -- something like |
| 12 | * |
| 13 | * sg->address = some_ptr; |
| 14 | * |
| 15 | * can be rewritten as |
| 16 | * |
| 17 | * sg->page = virt_to_page(some_ptr); |
| 18 | * sg->offset = (unsigned long) some_ptr & ~PAGE_MASK; |
| 19 | * |
| 20 | * and that's it. There's no excuse for not highmem enabling YOUR driver. /jens |
| 21 | */ |
| 22 | struct scatterlist { |
| 23 | struct page *page; /* Location for highmem page, if any */ |
| 24 | unsigned int offset; /* for highmem, page offset */ |
| 25 | |
| 26 | dma_addr_t dma_address; |
| 27 | unsigned int length; |
| 28 | }; |
| 29 | |
| 30 | #define ISA_DMA_THRESHOLD (0xffffffffUL) |
| 31 | |
| 32 | #endif /* !_ASM_SCATTERLIST_H */ |