| Marek Vasut | b660df3 | 2012-08-26 15:19:06 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Generic bounce buffer implementation |
| 3 | * |
| 4 | * Copyright (C) 2012 Marek Vasut <marex@denx.de> |
| 5 | * |
| 6 | * See file CREDITS for list of people who contributed to this |
| 7 | * project. |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or |
| 10 | * modify it under the terms of the GNU General Public License as |
| 11 | * published by the Free Software Foundation; either version 2 of |
| 12 | * the License, or (at your option) any later version. |
| 13 | * |
| 14 | * This program is distributed in the hope that it will be useful, |
| 15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 17 | * GNU General Public License for more details. |
| 18 | * |
| 19 | * You should have received a copy of the GNU General Public License |
| 20 | * along with this program; if not, write to the Free Software |
| 21 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, |
| 22 | * MA 02111-1307 USA |
| 23 | */ |
| 24 | |
| 25 | #include <common.h> |
| 26 | #include <malloc.h> |
| 27 | #include <errno.h> |
| 28 | #include <bouncebuf.h> |
| 29 | |
| 30 | static int addr_aligned(void *data, size_t len) |
| 31 | { |
| 32 | const ulong align_mask = ARCH_DMA_MINALIGN - 1; |
| 33 | |
| 34 | /* Check if start is aligned */ |
| 35 | if ((ulong)data & align_mask) { |
| 36 | debug("Unaligned start address %p\n", data); |
| 37 | return 0; |
| 38 | } |
| 39 | |
| 40 | data += len; |
| 41 | |
| 42 | /* Check if end is aligned */ |
| 43 | if ((ulong)data & align_mask) { |
| 44 | debug("Unaligned end address %p\n", data); |
| 45 | return 0; |
| 46 | } |
| 47 | |
| 48 | /* Aligned */ |
| 49 | return 1; |
| 50 | } |
| 51 | |
| 52 | int bounce_buffer_start(void **data, size_t len, void **backup, uint8_t flags) |
| 53 | { |
| 54 | void *tmp; |
| 55 | size_t alen; |
| 56 | |
| 57 | if (addr_aligned(*data, len)) { |
| 58 | *backup = NULL; |
| 59 | return 0; |
| 60 | } |
| 61 | |
| 62 | alen = roundup(len, ARCH_DMA_MINALIGN); |
| 63 | tmp = memalign(ARCH_DMA_MINALIGN, alen); |
| 64 | |
| 65 | if (!tmp) |
| 66 | return -ENOMEM; |
| 67 | |
| 68 | if (flags & GEN_BB_READ) |
| 69 | memcpy(tmp, *data, len); |
| 70 | |
| 71 | *backup = *data; |
| 72 | *data = tmp; |
| 73 | |
| 74 | return 0; |
| 75 | } |
| 76 | |
| 77 | int bounce_buffer_stop(void **data, size_t len, void **backup, uint8_t flags) |
| 78 | { |
| 79 | void *tmp = *data; |
| 80 | |
| 81 | /* The buffer was already aligned, since "backup" is NULL. */ |
| 82 | if (!*backup) |
| 83 | return 0; |
| 84 | |
| 85 | if (flags & GEN_BB_WRITE) |
| 86 | memcpy(*backup, *data, len); |
| 87 | |
| 88 | *data = *backup; |
| 89 | free(tmp); |
| 90 | |
| 91 | return 0; |
| 92 | } |