1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
|
/* pci-dma-nommu.c: Dynamic DMA mapping support for the FRV
*
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
* Written by David Woodhouse (dwmw2@infradead.org)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/list.h>
#include <linux/pci.h>
#include <asm/io.h>
#if 1
#define DMA_SRAM_START dma_coherent_mem_start
#define DMA_SRAM_END dma_coherent_mem_end
#else // Use video RAM on Matrox
#define DMA_SRAM_START 0xe8900000
#define DMA_SRAM_END 0xe8a00000
#endif
struct dma_alloc_record {
struct list_head list;
unsigned long ofs;
unsigned long len;
};
static DEFINE_SPINLOCK(dma_alloc_lock);
static LIST_HEAD(dma_alloc_list);
void *dma_alloc_coherent(struct device *hwdev, size_t size, dma_addr_t *dma_handle, gfp_t gfp)
{
struct dma_alloc_record *new;
struct list_head *this = &dma_alloc_list;
unsigned long flags;
unsigned long start = DMA_SRAM_START;
unsigned long end;
if (!DMA_SRAM_START) {
printk("%s called without any DMA area reserved!\n", __func__);
return NULL;
}
new = kmalloc(sizeof (*new), GFP_ATOMIC);
if (!new)
return NULL;
/* Round up to a reasonable alignment */
new->len = (size + 31) & ~31;
spin_lock_irqsave(&dma_alloc_lock, flags);
list_for_each (this, &dma_alloc_list) {
struct dma_alloc_record *this_r = list_entry(this, struct dma_alloc_record, list);
end = this_r->ofs;
if (end - start >= size)
goto gotone;
start = this_r->ofs + this_r->len;
}
/* Reached end of list. */
end = DMA_SRAM_END;
this = &dma_alloc_list;
if (end - start >= size) {
gotone:
new->ofs = start;
list_add_tail(&new->list, this);
spin_unlock_irqrestore(&dma_alloc_lock, flags);
*dma_handle = start;
return (void *)start;
}
kfree(new);
spin_unlock_irqrestore(&dma_alloc_lock, flags);
return NULL;
}
EXPORT_SYMBOL(dma_alloc_coherent);
void dma_free_coherent(struct device *hwdev, size_t size, void *vaddr, dma_addr_t dma_handle)
{
struct dma_alloc_record *rec;
unsigned long flags;
spin_lock_irqsave(&dma_alloc_lock, flags);
list_for_each_entry(rec, &dma_alloc_list, list) {
if (rec->ofs == dma_handle) {
list_del(&rec->list);
kfree(rec);
spin_unlock_irqrestore(&dma_alloc_lock, flags);
return;
}
}
spin_unlock_irqrestore(&dma_alloc_lock, flags);
BUG();
}
EXPORT_SYMBOL(dma_free_coherent);
/*
* Map a single buffer of the indicated size for DMA in streaming mode.
* The 32-bit bus address to use is returned.
*
* Once the device is given the dma address, the device owns this memory
* until either pci_unmap_single or pci_dma_sync_single is performed.
*/
dma_addr_t dma_map_single(struct device *dev, void *ptr, size_t size,
enum dma_data_direction direction)
{
if (direction == DMA_NONE)
BUG();
frv_cache_wback_inv((unsigned long) ptr, (unsigned long) ptr + size);
return virt_to_bus(ptr);
}
EXPORT_SYMBOL(dma_map_single);
/*
* Map a set of buffers described by scatterlist in streaming
* mode for DMA. This is the scather-gather version of the
* above pci_map_single interface. Here the scatter gather list
* elements are each tagged with the appropriate dma address
* and length. They are obtained via sg_dma_{address,length}(SG).
*
* NOTE: An implementation may be able to use a smaller number of
* DMA address/length pairs than there are SG table elements.
* (for example via virtual mapping capabilities)
* The routine returns the number of addr/length pairs actually
* used, at most nents.
*
* Device ownership issues as mentioned above for pci_map_single are
* the same here.
*/
int dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
enum dma_data_direction direction)
{
int i;
for (i=0; i<nents; i++)
frv_cache_wback_inv(sg_dma_address(&sg[i]),
sg_dma_address(&sg[i]) + sg_dma_len(&sg[i]));
if (direction == DMA_NONE)
BUG();
return nents;
}
EXPORT_SYMBOL(dma_map_sg);
|
