Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | #ifndef _ASM_SCATTERLIST_H |
| 2 | #define _ASM_SCATTERLIST_H |
| 3 | |
Jean Delvare | a9dfd28 | 2007-03-06 02:45:12 -0800 | [diff] [blame] | 4 | #include <asm/types.h> |
| 5 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6 | /* |
Jens Axboe | d09d276 | 2007-10-23 12:39:41 +0200 | [diff] [blame] | 7 | * Drivers must set either ->address or (preferred) page and ->offset |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 8 | * to indicate where data must be transferred to/from. |
| 9 | * |
Jens Axboe | d09d276 | 2007-10-23 12:39:41 +0200 | [diff] [blame] | 10 | * Using page is recommended since it handles highmem data as well as |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 11 | * low mem. ->address is restricted to data which has a virtual mapping, and |
Jens Axboe | d09d276 | 2007-10-23 12:39:41 +0200 | [diff] [blame] | 12 | * it will go away in the future. Updating to page can be automated very |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 13 | * easily -- something like |
| 14 | * |
| 15 | * sg->address = some_ptr; |
| 16 | * |
| 17 | * can be rewritten as |
| 18 | * |
Jens Axboe | 642f149 | 2007-10-24 11:20:47 +0200 | [diff] [blame] | 19 | * sg_set_buf(sg, some_ptr, length); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | * |
| 21 | * and that's it. There's no excuse for not highmem enabling YOUR driver. /jens |
| 22 | */ |
| 23 | struct scatterlist { |
Jens Axboe | d6ec084 | 2007-10-22 20:01:06 +0200 | [diff] [blame] | 24 | #ifdef CONFIG_DEBUG_SG |
| 25 | unsigned long sg_magic; |
| 26 | #endif |
Jens Axboe | 18dabf4 | 2007-10-22 19:57:20 +0200 | [diff] [blame] | 27 | unsigned long page_link; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | unsigned int offset; /* for highmem, page offset */ |
| 29 | |
| 30 | dma_addr_t dma_address; |
| 31 | unsigned int length; |
| 32 | }; |
| 33 | |
Robert P. J. Day | 82b12e2 | 2008-02-04 22:29:54 -0800 | [diff] [blame] | 34 | /* |
| 35 | * These macros should be used after a pci_map_sg call has been done |
| 36 | * to get bus addresses of each of the SG entries and their lengths. |
| 37 | * You should only work with the number of sg entries pci_map_sg |
| 38 | * returns, or alternatively stop on the first sg_dma_len(sg) which |
| 39 | * is 0. |
| 40 | */ |
| 41 | #define sg_dma_address(sg) ((sg)->dma_address) |
| 42 | #define sg_dma_len(sg) ((sg)->length) |
| 43 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | #define ISA_DMA_THRESHOLD (0xffffffffUL) |
| 45 | |
| 46 | #endif /* !_ASM_SCATTERLIST_H */ |