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git.ipfire.org Git - people/ms/u-boot.git/blob - common/bouncebuf.c
2 * Generic bounce buffer implementation
4 * Copyright (C) 2012 Marek Vasut <marex@denx.de>
6 * See file CREDITS for list of people who contributed to this
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.
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.
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,
28 #include <bouncebuf.h>
30 static int addr_aligned(struct bounce_buffer
*state
)
32 const ulong align_mask
= ARCH_DMA_MINALIGN
- 1;
34 /* Check if start is aligned */
35 if ((ulong
)state
->user_buffer
& align_mask
) {
36 debug("Unaligned buffer address %p\n", state
->user_buffer
);
40 /* Check if length is aligned */
41 if (state
->len
!= state
->len_aligned
) {
42 debug("Unaligned buffer length %d\n", state
->len
);
50 int bounce_buffer_start(struct bounce_buffer
*state
, void *data
,
51 size_t len
, unsigned int flags
)
53 state
->user_buffer
= data
;
54 state
->bounce_buffer
= data
;
56 state
->len_aligned
= roundup(len
, ARCH_DMA_MINALIGN
);
59 if (!addr_aligned(state
)) {
60 state
->bounce_buffer
= memalign(ARCH_DMA_MINALIGN
,
62 if (!state
->bounce_buffer
)
65 if (state
->flags
& GEN_BB_READ
)
66 memcpy(state
->bounce_buffer
, state
->user_buffer
,
71 * Flush data to RAM so DMA reads can pick it up,
72 * and any CPU writebacks don't race with DMA writes
74 flush_dcache_range((unsigned long)state
->bounce_buffer
,
75 (unsigned long)(state
->bounce_buffer
) +
81 int bounce_buffer_stop(struct bounce_buffer
*state
)
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
) +
90 if (state
->bounce_buffer
== state
->user_buffer
)
93 if (state
->flags
& GEN_BB_WRITE
)
94 memcpy(state
->user_buffer
, state
->bounce_buffer
, state
->len
);
96 free(state
->bounce_buffer
);