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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(struct bounce_buffer *state) | |
31 | { | |
32 | const ulong align_mask = ARCH_DMA_MINALIGN - 1; | |
33 | ||
34 | /* Check if start is aligned */ | |
35 | if ((ulong)state->user_buffer & align_mask) { | |
36 | debug("Unaligned buffer address %p\n", state->user_buffer); | |
37 | return 0; | |
38 | } | |
39 | ||
40 | /* Check if length is aligned */ | |
41 | if (state->len != state->len_aligned) { | |
42 | debug("Unaligned buffer length %d\n", state->len); | |
43 | return 0; | |
44 | } | |
45 | ||
46 | /* Aligned */ | |
47 | return 1; | |
48 | } | |
49 | ||
50 | int bounce_buffer_start(struct bounce_buffer *state, void *data, | |
51 | size_t len, unsigned int flags) | |
52 | { | |
53 | state->user_buffer = data; | |
54 | state->bounce_buffer = data; | |
55 | state->len = len; | |
56 | state->len_aligned = roundup(len, ARCH_DMA_MINALIGN); | |
57 | state->flags = flags; | |
58 | ||
59 | if (!addr_aligned(state)) { | |
60 | state->bounce_buffer = memalign(ARCH_DMA_MINALIGN, | |
61 | state->len_aligned); | |
62 | if (!state->bounce_buffer) | |
63 | return -ENOMEM; | |
64 | ||
65 | if (state->flags & GEN_BB_READ) | |
66 | memcpy(state->bounce_buffer, state->user_buffer, | |
67 | state->len); | |
68 | } | |
69 | ||
70 | /* | |
71 | * Flush data to RAM so DMA reads can pick it up, | |
72 | * and any CPU writebacks don't race with DMA writes | |
73 | */ | |
74 | flush_dcache_range((unsigned long)state->bounce_buffer, | |
75 | (unsigned long)(state->bounce_buffer) + | |
76 | state->len_aligned); | |
77 | ||
78 | return 0; | |
79 | } | |
80 | ||
81 | int bounce_buffer_stop(struct bounce_buffer *state) | |
82 | { | |
83 | if (state->flags & GEN_BB_WRITE) { | |
84 | /* Invalidate cache so that CPU can see any newly DMA'd data */ | |
85 | invalidate_dcache_range((unsigned long)state->bounce_buffer, | |
86 | (unsigned long)(state->bounce_buffer) + | |
87 | state->len_aligned); | |
88 | } | |
89 | ||
90 | if (state->bounce_buffer == state->user_buffer) | |
91 | return 0; | |
92 | ||
93 | if (state->flags & GEN_BB_WRITE) | |
94 | memcpy(state->user_buffer, state->bounce_buffer, state->len); | |
95 | ||
96 | free(state->bounce_buffer); | |
97 | ||
98 | return 0; | |
99 | } |