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 <cpu_func.h>
10 #include <log.h>
11 #include <malloc.h>
12 #include <errno.h>
13 #include <bouncebuf.h>
14 #include <asm/cache.h>
15 #include <linux/dma-mapping.h>
16
addr_aligned(struct bounce_buffer * state)17 static int addr_aligned(struct bounce_buffer *state)
18 {
19 const ulong align_mask = ARCH_DMA_MINALIGN - 1;
20
21 /* Check if start is aligned */
22 if ((ulong)state->user_buffer & align_mask) {
23 debug("Unaligned buffer address %p\n", state->user_buffer);
24 return 0;
25 }
26
27 /* Check if length is aligned */
28 if (state->len != state->len_aligned) {
29 debug("Unaligned buffer length %zu\n", state->len);
30 return 0;
31 }
32
33 /* Aligned */
34 return 1;
35 }
36
bounce_buffer_start_extalign(struct bounce_buffer * state,void * data,size_t len,unsigned int flags,size_t alignment,int (* addr_is_aligned)(struct bounce_buffer * state))37 int bounce_buffer_start_extalign(struct bounce_buffer *state, void *data,
38 size_t len, unsigned int flags,
39 size_t alignment,
40 int (*addr_is_aligned)(struct bounce_buffer *state))
41 {
42 state->user_buffer = data;
43 state->bounce_buffer = data;
44 state->len = len;
45 state->len_aligned = roundup(len, alignment);
46 state->flags = flags;
47
48 if (!addr_is_aligned(state)) {
49 state->bounce_buffer = memalign(alignment,
50 state->len_aligned);
51 if (!state->bounce_buffer)
52 return -ENOMEM;
53
54 if (state->flags & GEN_BB_READ)
55 memcpy(state->bounce_buffer, state->user_buffer,
56 state->len);
57 }
58
59 /*
60 * Flush data to RAM so DMA reads can pick it up,
61 * and any CPU writebacks don't race with DMA writes
62 */
63 dma_map_single(state->bounce_buffer,
64 state->len_aligned,
65 DMA_BIDIRECTIONAL);
66
67 return 0;
68 }
69
bounce_buffer_start(struct bounce_buffer * state,void * data,size_t len,unsigned int flags)70 int bounce_buffer_start(struct bounce_buffer *state, void *data,
71 size_t len, unsigned int flags)
72 {
73 return bounce_buffer_start_extalign(state, data, len, flags,
74 ARCH_DMA_MINALIGN,
75 addr_aligned);
76 }
77
bounce_buffer_stop(struct bounce_buffer * state)78 int bounce_buffer_stop(struct bounce_buffer *state)
79 {
80 if (state->flags & GEN_BB_WRITE) {
81 /* Invalidate cache so that CPU can see any newly DMA'd data */
82 dma_unmap_single((dma_addr_t)state->bounce_buffer,
83 state->len_aligned,
84 DMA_BIDIRECTIONAL);
85 }
86
87 if (state->bounce_buffer == state->user_buffer)
88 return 0;
89
90 if (state->flags & GEN_BB_WRITE)
91 memcpy(state->user_buffer, state->bounce_buffer, state->len);
92
93 free(state->bounce_buffer);
94
95 return 0;
96 }
97