1 /* pci-dma-nommu.c: Dynamic DMA mapping support for the FRV
2 *
3 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
4 * Written by David Woodhouse (dwmw2@infradead.org)
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/export.h>
15 #include <linux/dma-mapping.h>
16 #include <linux/list.h>
17 #include <linux/pci.h>
18 #include <asm/io.h>
19
20 #if 1
21 #define DMA_SRAM_START dma_coherent_mem_start
22 #define DMA_SRAM_END dma_coherent_mem_end
23 #else // Use video RAM on Matrox
24 #define DMA_SRAM_START 0xe8900000
25 #define DMA_SRAM_END 0xe8a00000
26 #endif
27
28 struct dma_alloc_record {
29 struct list_head list;
30 unsigned long ofs;
31 unsigned long len;
32 };
33
34 static DEFINE_SPINLOCK(dma_alloc_lock);
35 static LIST_HEAD(dma_alloc_list);
36
dma_alloc_coherent(struct device * hwdev,size_t size,dma_addr_t * dma_handle,gfp_t gfp)37 void *dma_alloc_coherent(struct device *hwdev, size_t size, dma_addr_t *dma_handle, gfp_t gfp)
38 {
39 struct dma_alloc_record *new;
40 struct list_head *this = &dma_alloc_list;
41 unsigned long flags;
42 unsigned long start = DMA_SRAM_START;
43 unsigned long end;
44
45 if (!DMA_SRAM_START) {
46 printk("%s called without any DMA area reserved!\n", __func__);
47 return NULL;
48 }
49
50 new = kmalloc(sizeof (*new), GFP_ATOMIC);
51 if (!new)
52 return NULL;
53
54 /* Round up to a reasonable alignment */
55 new->len = (size + 31) & ~31;
56
57 spin_lock_irqsave(&dma_alloc_lock, flags);
58
59 list_for_each (this, &dma_alloc_list) {
60 struct dma_alloc_record *this_r = list_entry(this, struct dma_alloc_record, list);
61 end = this_r->ofs;
62
63 if (end - start >= size)
64 goto gotone;
65
66 start = this_r->ofs + this_r->len;
67 }
68 /* Reached end of list. */
69 end = DMA_SRAM_END;
70 this = &dma_alloc_list;
71
72 if (end - start >= size) {
73 gotone:
74 new->ofs = start;
75 list_add_tail(&new->list, this);
76 spin_unlock_irqrestore(&dma_alloc_lock, flags);
77
78 *dma_handle = start;
79 return (void *)start;
80 }
81
82 kfree(new);
83 spin_unlock_irqrestore(&dma_alloc_lock, flags);
84 return NULL;
85 }
86
87 EXPORT_SYMBOL(dma_alloc_coherent);
88
dma_free_coherent(struct device * hwdev,size_t size,void * vaddr,dma_addr_t dma_handle)89 void dma_free_coherent(struct device *hwdev, size_t size, void *vaddr, dma_addr_t dma_handle)
90 {
91 struct dma_alloc_record *rec;
92 unsigned long flags;
93
94 spin_lock_irqsave(&dma_alloc_lock, flags);
95
96 list_for_each_entry(rec, &dma_alloc_list, list) {
97 if (rec->ofs == dma_handle) {
98 list_del(&rec->list);
99 kfree(rec);
100 spin_unlock_irqrestore(&dma_alloc_lock, flags);
101 return;
102 }
103 }
104 spin_unlock_irqrestore(&dma_alloc_lock, flags);
105 BUG();
106 }
107
108 EXPORT_SYMBOL(dma_free_coherent);
109
dma_map_single(struct device * dev,void * ptr,size_t size,enum dma_data_direction direction)110 dma_addr_t dma_map_single(struct device *dev, void *ptr, size_t size,
111 enum dma_data_direction direction)
112 {
113 BUG_ON(direction == DMA_NONE);
114
115 frv_cache_wback_inv((unsigned long) ptr, (unsigned long) ptr + size);
116
117 return virt_to_bus(ptr);
118 }
119
120 EXPORT_SYMBOL(dma_map_single);
121
dma_map_sg(struct device * dev,struct scatterlist * sglist,int nents,enum dma_data_direction direction)122 int dma_map_sg(struct device *dev, struct scatterlist *sglist, int nents,
123 enum dma_data_direction direction)
124 {
125 int i;
126 struct scatterlist *sg;
127
128 for_each_sg(sglist, sg, nents, i) {
129 frv_cache_wback_inv(sg_dma_address(sg),
130 sg_dma_address(sg) + sg_dma_len(sg));
131 }
132
133 BUG_ON(direction == DMA_NONE);
134
135 return nents;
136 }
137
138 EXPORT_SYMBOL(dma_map_sg);
139
dma_map_page(struct device * dev,struct page * page,unsigned long offset,size_t size,enum dma_data_direction direction)140 dma_addr_t dma_map_page(struct device *dev, struct page *page, unsigned long offset,
141 size_t size, enum dma_data_direction direction)
142 {
143 BUG_ON(direction == DMA_NONE);
144 flush_dcache_page(page);
145 return (dma_addr_t) page_to_phys(page) + offset;
146 }
147
148 EXPORT_SYMBOL(dma_map_page);
149