Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux...
[linux-2.6] / arch / x86 / kernel / pci-dma_32.c
1 /*
2  * Dynamic DMA mapping support.
3  *
4  * On i386 there is no hardware dynamic DMA address translation,
5  * so consistent alloc/free are merely page allocation/freeing.
6  * The rest of the dynamic DMA mapping interface is implemented
7  * in asm/pci.h.
8  */
9
10 #include <linux/types.h>
11 #include <linux/mm.h>
12 #include <linux/string.h>
13 #include <linux/pci.h>
14 #include <linux/module.h>
15 #include <asm/io.h>
16
17 struct dma_coherent_mem {
18         void            *virt_base;
19         u32             device_base;
20         int             size;
21         int             flags;
22         unsigned long   *bitmap;
23 };
24
25 void *dma_alloc_coherent(struct device *dev, size_t size,
26                            dma_addr_t *dma_handle, gfp_t gfp)
27 {
28         void *ret;
29         struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
30         int order = get_order(size);
31         /* ignore region specifiers */
32         gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
33
34         if (mem) {
35                 int page = bitmap_find_free_region(mem->bitmap, mem->size,
36                                                      order);
37                 if (page >= 0) {
38                         *dma_handle = mem->device_base + (page << PAGE_SHIFT);
39                         ret = mem->virt_base + (page << PAGE_SHIFT);
40                         memset(ret, 0, size);
41                         return ret;
42                 }
43                 if (mem->flags & DMA_MEMORY_EXCLUSIVE)
44                         return NULL;
45         }
46
47         if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
48                 gfp |= GFP_DMA;
49
50         ret = (void *)__get_free_pages(gfp, order);
51
52         if (ret != NULL) {
53                 memset(ret, 0, size);
54                 *dma_handle = virt_to_phys(ret);
55         }
56         return ret;
57 }
58 EXPORT_SYMBOL(dma_alloc_coherent);
59
60 void dma_free_coherent(struct device *dev, size_t size,
61                          void *vaddr, dma_addr_t dma_handle)
62 {
63         struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
64         int order = get_order(size);
65
66         WARN_ON(irqs_disabled());       /* for portability */
67         if (mem && vaddr >= mem->virt_base && vaddr < (mem->virt_base + (mem->size << PAGE_SHIFT))) {
68                 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
69
70                 bitmap_release_region(mem->bitmap, page, order);
71         } else
72                 free_pages((unsigned long)vaddr, order);
73 }
74 EXPORT_SYMBOL(dma_free_coherent);
75
76 int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
77                                 dma_addr_t device_addr, size_t size, int flags)
78 {
79         void __iomem *mem_base = NULL;
80         int pages = size >> PAGE_SHIFT;
81         int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
82
83         if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
84                 goto out;
85         if (!size)
86                 goto out;
87         if (dev->dma_mem)
88                 goto out;
89
90         /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
91
92         mem_base = ioremap(bus_addr, size);
93         if (!mem_base)
94                 goto out;
95
96         dev->dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
97         if (!dev->dma_mem)
98                 goto out;
99         dev->dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
100         if (!dev->dma_mem->bitmap)
101                 goto free1_out;
102
103         dev->dma_mem->virt_base = mem_base;
104         dev->dma_mem->device_base = device_addr;
105         dev->dma_mem->size = pages;
106         dev->dma_mem->flags = flags;
107
108         if (flags & DMA_MEMORY_MAP)
109                 return DMA_MEMORY_MAP;
110
111         return DMA_MEMORY_IO;
112
113  free1_out:
114         kfree(dev->dma_mem);
115  out:
116         if (mem_base)
117                 iounmap(mem_base);
118         return 0;
119 }
120 EXPORT_SYMBOL(dma_declare_coherent_memory);
121
122 void dma_release_declared_memory(struct device *dev)
123 {
124         struct dma_coherent_mem *mem = dev->dma_mem;
125         
126         if(!mem)
127                 return;
128         dev->dma_mem = NULL;
129         iounmap(mem->virt_base);
130         kfree(mem->bitmap);
131         kfree(mem);
132 }
133 EXPORT_SYMBOL(dma_release_declared_memory);
134
135 void *dma_mark_declared_memory_occupied(struct device *dev,
136                                         dma_addr_t device_addr, size_t size)
137 {
138         struct dma_coherent_mem *mem = dev->dma_mem;
139         int pages = (size + (device_addr & ~PAGE_MASK) + PAGE_SIZE - 1) >> PAGE_SHIFT;
140         int pos, err;
141
142         if (!mem)
143                 return ERR_PTR(-EINVAL);
144
145         pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
146         err = bitmap_allocate_region(mem->bitmap, pos, get_order(pages));
147         if (err != 0)
148                 return ERR_PTR(err);
149         return mem->virt_base + (pos << PAGE_SHIFT);
150 }
151 EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
152
153 #ifdef CONFIG_PCI
154 /* Many VIA bridges seem to corrupt data for DAC. Disable it here */
155
156 int forbid_dac;
157 EXPORT_SYMBOL(forbid_dac);
158
159 static __devinit void via_no_dac(struct pci_dev *dev)
160 {
161         if ((dev->class >> 8) == PCI_CLASS_BRIDGE_PCI && forbid_dac == 0) {
162                 printk(KERN_INFO "PCI: VIA PCI bridge detected. Disabling DAC.\n");
163                 forbid_dac = 1;
164         }
165 }
166 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID, via_no_dac);
167
168 static int check_iommu(char *s)
169 {
170         if (!strcmp(s, "usedac")) {
171                 forbid_dac = -1;
172                 return 1;
173         }
174         return 0;
175 }
176 __setup("iommu=", check_iommu);
177 #endif