1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Generic bounce buffer implementation
4 *
5 * Copyright (C) 2012 Marek Vasut <marex@denx.de>
6 */
7
8 #include <common.h>
9 #include <malloc.h>
10 #include <errno.h>
11 #include <bouncebuf.h>
12
addr_aligned(struct bounce_buffer * state)13 static int addr_aligned(struct bounce_buffer *state)
14 {
15 const ulong align_mask = ARCH_DMA_MINALIGN - 1;
16
17 /* Check if start is aligned */
18 if ((ulong)state->user_buffer & align_mask) {
19 debug("Unaligned buffer address %p\n", state->user_buffer);
20 return 0;
21 }
22
23 /* Check if length is aligned */
24 if (state->len != state->len_aligned) {
25 debug("Unaligned buffer length %zu\n", state->len);
26 return 0;
27 }
28
29 /* Aligned */
30 return 1;
31 }
32
bounce_buffer_start(struct bounce_buffer * state,void * data,size_t len,unsigned int flags)33 int bounce_buffer_start(struct bounce_buffer *state, void *data,
34 size_t len, unsigned int flags)
35 {
36 state->user_buffer = data;
37 state->bounce_buffer = data;
38 state->len = len;
39 state->len_aligned = roundup(len, ARCH_DMA_MINALIGN);
40 state->flags = flags;
41
42 if (!addr_aligned(state)) {
43 state->bounce_buffer = memalign(ARCH_DMA_MINALIGN,
44 state->len_aligned);
45 if (!state->bounce_buffer)
46 return -ENOMEM;
47
48 if (state->flags & GEN_BB_READ)
49 memcpy(state->bounce_buffer, state->user_buffer,
50 state->len);
51 }
52
53 /*
54 * Flush data to RAM so DMA reads can pick it up,
55 * and any CPU writebacks don't race with DMA writes
56 */
57 flush_dcache_range((unsigned long)state->bounce_buffer,
58 (unsigned long)(state->bounce_buffer) +
59 state->len_aligned);
60
61 return 0;
62 }
63
bounce_buffer_stop(struct bounce_buffer * state)64 int bounce_buffer_stop(struct bounce_buffer *state)
65 {
66 if (state->flags & GEN_BB_WRITE) {
67 /* Invalidate cache so that CPU can see any newly DMA'd data */
68 invalidate_dcache_range((unsigned long)state->bounce_buffer,
69 (unsigned long)(state->bounce_buffer) +
70 state->len_aligned);
71 }
72
73 if (state->bounce_buffer == state->user_buffer)
74 return 0;
75
76 if (state->flags & GEN_BB_WRITE)
77 memcpy(state->user_buffer, state->bounce_buffer, state->len);
78
79 free(state->bounce_buffer);
80
81 return 0;
82 }
83