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1da177e4 LT |
1 | /* pci-dma-nommu.c: Dynamic DMA mapping support for the FRV |
2 | * | |
3 | * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. | |
44d1b980 | 4 | * Written by David Woodhouse (dwmw2@infradead.org) |
1da177e4 LT |
5 | * |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/types.h> | |
13 | #include <linux/slab.h> | |
14 | #include <linux/dma-mapping.h> | |
15 | #include <linux/list.h> | |
16 | #include <linux/pci.h> | |
17 | #include <asm/io.h> | |
18 | ||
19 | #if 1 | |
20 | #define DMA_SRAM_START dma_coherent_mem_start | |
21 | #define DMA_SRAM_END dma_coherent_mem_end | |
22 | #else // Use video RAM on Matrox | |
23 | #define DMA_SRAM_START 0xe8900000 | |
24 | #define DMA_SRAM_END 0xe8a00000 | |
25 | #endif | |
26 | ||
27 | struct dma_alloc_record { | |
28 | struct list_head list; | |
29 | unsigned long ofs; | |
30 | unsigned long len; | |
31 | }; | |
32 | ||
33 | static DEFINE_SPINLOCK(dma_alloc_lock); | |
34 | static LIST_HEAD(dma_alloc_list); | |
35 | ||
a5da7d3c | 36 | void *dma_alloc_coherent(struct device *hwdev, size_t size, dma_addr_t *dma_handle, gfp_t gfp) |
1da177e4 LT |
37 | { |
38 | struct dma_alloc_record *new; | |
39 | struct list_head *this = &dma_alloc_list; | |
40 | unsigned long flags; | |
41 | unsigned long start = DMA_SRAM_START; | |
42 | unsigned long end; | |
43 | ||
44 | if (!DMA_SRAM_START) { | |
45 | printk("%s called without any DMA area reserved!\n", __func__); | |
46 | return NULL; | |
47 | } | |
48 | ||
49 | new = kmalloc(sizeof (*new), GFP_ATOMIC); | |
50 | if (!new) | |
51 | return NULL; | |
52 | ||
53 | /* Round up to a reasonable alignment */ | |
54 | new->len = (size + 31) & ~31; | |
55 | ||
56 | spin_lock_irqsave(&dma_alloc_lock, flags); | |
57 | ||
58 | list_for_each (this, &dma_alloc_list) { | |
59 | struct dma_alloc_record *this_r = list_entry(this, struct dma_alloc_record, list); | |
60 | end = this_r->ofs; | |
61 | ||
62 | if (end - start >= size) | |
63 | goto gotone; | |
64 | ||
65 | start = this_r->ofs + this_r->len; | |
66 | } | |
67 | /* Reached end of list. */ | |
68 | end = DMA_SRAM_END; | |
69 | this = &dma_alloc_list; | |
70 | ||
71 | if (end - start >= size) { | |
72 | gotone: | |
73 | new->ofs = start; | |
74 | list_add_tail(&new->list, this); | |
75 | spin_unlock_irqrestore(&dma_alloc_lock, flags); | |
76 | ||
77 | *dma_handle = start; | |
78 | return (void *)start; | |
79 | } | |
80 | ||
81 | kfree(new); | |
82 | spin_unlock_irqrestore(&dma_alloc_lock, flags); | |
83 | return NULL; | |
84 | } | |
85 | ||
40234401 DH |
86 | EXPORT_SYMBOL(dma_alloc_coherent); |
87 | ||
1da177e4 LT |
88 | void dma_free_coherent(struct device *hwdev, size_t size, void *vaddr, dma_addr_t dma_handle) |
89 | { | |
90 | struct dma_alloc_record *rec; | |
91 | unsigned long flags; | |
92 | ||
93 | spin_lock_irqsave(&dma_alloc_lock, flags); | |
94 | ||
95 | list_for_each_entry(rec, &dma_alloc_list, list) { | |
96 | if (rec->ofs == dma_handle) { | |
97 | list_del(&rec->list); | |
98 | kfree(rec); | |
99 | spin_unlock_irqrestore(&dma_alloc_lock, flags); | |
100 | return; | |
101 | } | |
102 | } | |
103 | spin_unlock_irqrestore(&dma_alloc_lock, flags); | |
104 | BUG(); | |
105 | } | |
106 | ||
40234401 DH |
107 | EXPORT_SYMBOL(dma_free_coherent); |
108 | ||
1da177e4 LT |
109 | /* |
110 | * Map a single buffer of the indicated size for DMA in streaming mode. | |
111 | * The 32-bit bus address to use is returned. | |
112 | * | |
113 | * Once the device is given the dma address, the device owns this memory | |
c9af956c | 114 | * until either dma_unmap_single or pci_dma_sync_single is performed. |
1da177e4 LT |
115 | */ |
116 | dma_addr_t dma_map_single(struct device *dev, void *ptr, size_t size, | |
117 | enum dma_data_direction direction) | |
118 | { | |
db5c444e | 119 | BUG_ON(direction == DMA_NONE); |
1da177e4 LT |
120 | |
121 | frv_cache_wback_inv((unsigned long) ptr, (unsigned long) ptr + size); | |
122 | ||
123 | return virt_to_bus(ptr); | |
124 | } | |
125 | ||
40234401 DH |
126 | EXPORT_SYMBOL(dma_map_single); |
127 | ||
1da177e4 LT |
128 | /* |
129 | * Map a set of buffers described by scatterlist in streaming | |
130 | * mode for DMA. This is the scather-gather version of the | |
c9af956c | 131 | * above dma_map_single interface. Here the scatter gather list |
1da177e4 LT |
132 | * elements are each tagged with the appropriate dma address |
133 | * and length. They are obtained via sg_dma_{address,length}(SG). | |
134 | * | |
135 | * NOTE: An implementation may be able to use a smaller number of | |
136 | * DMA address/length pairs than there are SG table elements. | |
137 | * (for example via virtual mapping capabilities) | |
138 | * The routine returns the number of addr/length pairs actually | |
139 | * used, at most nents. | |
140 | * | |
c9af956c | 141 | * Device ownership issues as mentioned above for dma_map_single are |
1da177e4 LT |
142 | * the same here. |
143 | */ | |
144 | int dma_map_sg(struct device *dev, struct scatterlist *sg, int nents, | |
145 | enum dma_data_direction direction) | |
146 | { | |
147 | int i; | |
148 | ||
149 | for (i=0; i<nents; i++) | |
150 | frv_cache_wback_inv(sg_dma_address(&sg[i]), | |
151 | sg_dma_address(&sg[i]) + sg_dma_len(&sg[i])); | |
152 | ||
db5c444e | 153 | BUG_ON(direction == DMA_NONE); |
1da177e4 LT |
154 | |
155 | return nents; | |
156 | } | |
40234401 DH |
157 | |
158 | EXPORT_SYMBOL(dma_map_sg); | |
c9af956c DH |
159 | |
160 | /* | |
161 | * Map a single page of the indicated size for DMA in streaming mode. | |
162 | * The 32-bit bus address to use is returned. | |
163 | * | |
164 | * Device ownership issues as mentioned above for dma_map_single are | |
165 | * the same here. | |
166 | */ | |
167 | dma_addr_t dma_map_page(struct device *dev, struct page *page, unsigned long offset, | |
168 | size_t size, enum dma_data_direction direction) | |
169 | { | |
170 | BUG_ON(direction == DMA_NONE); | |
171 | flush_dcache_page(page); | |
172 | return (dma_addr_t) page_to_phys(page) + offset; | |
173 | } | |
174 | ||
175 | EXPORT_SYMBOL(dma_map_page); |