2 * Dynamic DMA mapping support.
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
10 #include <linux/types.h>
12 #include <linux/string.h>
13 #include <linux/pci.h>
14 #include <linux/module.h>
15 #include <linux/pci.h>
18 struct dma_coherent_mem {
23 unsigned long *bitmap;
26 void *dma_alloc_coherent(struct device *dev, size_t size,
27 dma_addr_t *dma_handle, gfp_t gfp)
30 struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
31 int order = get_order(size);
32 /* ignore region specifiers */
33 gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
36 int page = bitmap_find_free_region(mem->bitmap, mem->size,
39 *dma_handle = mem->device_base + (page << PAGE_SHIFT);
40 ret = mem->virt_base + (page << PAGE_SHIFT);
44 if (mem->flags & DMA_MEMORY_EXCLUSIVE)
48 if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
51 ret = (void *)__get_free_pages(gfp, order);
55 *dma_handle = virt_to_phys(ret);
59 EXPORT_SYMBOL(dma_alloc_coherent);
61 void dma_free_coherent(struct device *dev, size_t size,
62 void *vaddr, dma_addr_t dma_handle)
64 struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
65 int order = get_order(size);
67 WARN_ON(irqs_disabled()); /* for portability */
68 if (mem && vaddr >= mem->virt_base && vaddr < (mem->virt_base + (mem->size << PAGE_SHIFT))) {
69 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
71 bitmap_release_region(mem->bitmap, page, order);
73 free_pages((unsigned long)vaddr, order);
75 EXPORT_SYMBOL(dma_free_coherent);
77 int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
78 dma_addr_t device_addr, size_t size, int flags)
80 void __iomem *mem_base = NULL;
81 int pages = size >> PAGE_SHIFT;
82 int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
84 if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
91 /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
93 mem_base = ioremap(bus_addr, size);
97 dev->dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
100 dev->dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
101 if (!dev->dma_mem->bitmap)
104 dev->dma_mem->virt_base = mem_base;
105 dev->dma_mem->device_base = device_addr;
106 dev->dma_mem->size = pages;
107 dev->dma_mem->flags = flags;
109 if (flags & DMA_MEMORY_MAP)
110 return DMA_MEMORY_MAP;
112 return DMA_MEMORY_IO;
121 EXPORT_SYMBOL(dma_declare_coherent_memory);
123 void dma_release_declared_memory(struct device *dev)
125 struct dma_coherent_mem *mem = dev->dma_mem;
130 iounmap(mem->virt_base);
134 EXPORT_SYMBOL(dma_release_declared_memory);
136 void *dma_mark_declared_memory_occupied(struct device *dev,
137 dma_addr_t device_addr, size_t size)
139 struct dma_coherent_mem *mem = dev->dma_mem;
140 int pages = (size + (device_addr & ~PAGE_MASK) + PAGE_SIZE - 1) >> PAGE_SHIFT;
144 return ERR_PTR(-EINVAL);
146 pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
147 err = bitmap_allocate_region(mem->bitmap, pos, get_order(pages));
150 return mem->virt_base + (pos << PAGE_SHIFT);
152 EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
155 /* Many VIA bridges seem to corrupt data for DAC. Disable it here */
158 EXPORT_SYMBOL(forbid_dac);
160 static __devinit void via_no_dac(struct pci_dev *dev)
162 if ((dev->class >> 8) == PCI_CLASS_BRIDGE_PCI && forbid_dac == 0) {
163 printk(KERN_INFO "PCI: VIA PCI bridge detected. Disabling DAC.\n");
167 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID, via_no_dac);
169 static int check_iommu(char *s)
171 if (!strcmp(s, "usedac")) {
177 __setup("iommu=", check_iommu);