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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 * SPDX-License-Identifier: GPL-2.0+
12 #include <bouncebuf.h>
14 static int addr_aligned(struct bounce_buffer
*state
)
16 const ulong align_mask
= ARCH_DMA_MINALIGN
- 1;
18 /* Check if start is aligned */
19 if ((ulong
)state
->user_buffer
& align_mask
) {
20 debug("Unaligned buffer address %p\n", state
->user_buffer
);
24 /* Check if length is aligned */
25 if (state
->len
!= state
->len_aligned
) {
26 debug("Unaligned buffer length %zu\n", state
->len
);
34 int bounce_buffer_start(struct bounce_buffer
*state
, void *data
,
35 size_t len
, unsigned int flags
)
37 state
->user_buffer
= data
;
38 state
->bounce_buffer
= data
;
40 state
->len_aligned
= roundup(len
, ARCH_DMA_MINALIGN
);
43 if (!addr_aligned(state
)) {
44 state
->bounce_buffer
= memalign(ARCH_DMA_MINALIGN
,
46 if (!state
->bounce_buffer
)
49 if (state
->flags
& GEN_BB_READ
)
50 memcpy(state
->bounce_buffer
, state
->user_buffer
,
55 * Flush data to RAM so DMA reads can pick it up,
56 * and any CPU writebacks don't race with DMA writes
58 flush_dcache_range((unsigned long)state
->bounce_buffer
,
59 (unsigned long)(state
->bounce_buffer
) +
65 int bounce_buffer_stop(struct bounce_buffer
*state
)
67 if (state
->flags
& GEN_BB_WRITE
) {
68 /* Invalidate cache so that CPU can see any newly DMA'd data */
69 invalidate_dcache_range((unsigned long)state
->bounce_buffer
,
70 (unsigned long)(state
->bounce_buffer
) +
74 if (state
->bounce_buffer
== state
->user_buffer
)
77 if (state
->flags
& GEN_BB_WRITE
)
78 memcpy(state
->user_buffer
, state
->bounce_buffer
, state
->len
);
80 free(state
->bounce_buffer
);