David S. Miller | a40c24a | 2008-09-11 04:51:14 -0700 | [diff] [blame] | 1 | /* skb_dma_map.c: DMA mapping helpers for socket buffers. |
| 2 | * |
| 3 | * Copyright (C) David S. Miller <davem@davemloft.net> |
| 4 | */ |
| 5 | |
| 6 | #include <linux/kernel.h> |
| 7 | #include <linux/module.h> |
| 8 | #include <linux/dma-mapping.h> |
| 9 | #include <linux/skbuff.h> |
| 10 | |
| 11 | int skb_dma_map(struct device *dev, struct sk_buff *skb, |
| 12 | enum dma_data_direction dir) |
| 13 | { |
| 14 | struct skb_shared_info *sp = skb_shinfo(skb); |
| 15 | dma_addr_t map; |
| 16 | int i; |
| 17 | |
| 18 | map = dma_map_single(dev, skb->data, |
| 19 | skb_headlen(skb), dir); |
| 20 | if (dma_mapping_error(dev, map)) |
| 21 | goto out_err; |
| 22 | |
| 23 | sp->dma_maps[0] = map; |
| 24 | for (i = 0; i < sp->nr_frags; i++) { |
| 25 | skb_frag_t *fp = &sp->frags[i]; |
| 26 | |
| 27 | map = dma_map_page(dev, fp->page, fp->page_offset, |
| 28 | fp->size, dir); |
| 29 | if (dma_mapping_error(dev, map)) |
| 30 | goto unwind; |
| 31 | sp->dma_maps[i + 1] = map; |
| 32 | } |
| 33 | sp->num_dma_maps = i + 1; |
| 34 | |
| 35 | return 0; |
| 36 | |
| 37 | unwind: |
Dimitris Michailidis | ab396eb | 2008-10-12 21:07:34 -0700 | [diff] [blame] | 38 | while (--i >= 0) { |
David S. Miller | a40c24a | 2008-09-11 04:51:14 -0700 | [diff] [blame] | 39 | skb_frag_t *fp = &sp->frags[i]; |
| 40 | |
| 41 | dma_unmap_page(dev, sp->dma_maps[i + 1], |
| 42 | fp->size, dir); |
| 43 | } |
| 44 | dma_unmap_single(dev, sp->dma_maps[0], |
| 45 | skb_headlen(skb), dir); |
| 46 | out_err: |
| 47 | return -ENOMEM; |
| 48 | } |
| 49 | EXPORT_SYMBOL(skb_dma_map); |
| 50 | |
| 51 | void skb_dma_unmap(struct device *dev, struct sk_buff *skb, |
| 52 | enum dma_data_direction dir) |
| 53 | { |
| 54 | struct skb_shared_info *sp = skb_shinfo(skb); |
| 55 | int i; |
| 56 | |
| 57 | dma_unmap_single(dev, sp->dma_maps[0], |
| 58 | skb_headlen(skb), dir); |
| 59 | for (i = 0; i < sp->nr_frags; i++) { |
| 60 | skb_frag_t *fp = &sp->frags[i]; |
| 61 | |
| 62 | dma_unmap_page(dev, sp->dma_maps[i + 1], |
| 63 | fp->size, dir); |
| 64 | } |
| 65 | } |
| 66 | EXPORT_SYMBOL(skb_dma_unmap); |