2 * Dynamic DMA mapping support.
5 #include <linux/types.h>
7 #include <linux/string.h>
9 #include <linux/module.h>
10 #include <linux/dmar.h>
11 #include <linux/bootmem.h>
12 #include <asm/proto.h>
15 #include <asm/calgary.h>
18 /* Dummy device used for NULL arguments (normally ISA). Better would
19 be probably a smaller DMA mask, but this is bug-to-bug compatible
21 struct device fallback_dev = {
22 .bus_id = "fallback device",
23 .coherent_dma_mask = DMA_32BIT_MASK,
24 .dma_mask = &fallback_dev.coherent_dma_mask,
27 /* Allocate DMA memory on node near device */
28 noinline static void *
29 dma_alloc_pages(struct device *dev, gfp_t gfp, unsigned order)
33 node = dev_to_node(dev);
35 return alloc_pages_node(node, gfp, order);
38 #define dma_alloc_from_coherent_mem(dev, size, handle, ret) (0)
39 #define dma_release_coherent(dev, order, vaddr) (0)
41 * Allocate memory for a coherent mapping.
44 dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle,
49 unsigned long dma_mask = 0;
53 if (dma_alloc_from_coherent_mem(dev, size, dma_handle, &memory))
58 dma_mask = dev->coherent_dma_mask;
60 dma_mask = DMA_32BIT_MASK;
62 /* Device not DMA able */
63 if (dev->dma_mask == NULL)
66 /* Don't invoke OOM killer */
69 /* Kludge to make it bug-to-bug compatible with i386. i386
70 uses the normal dma_mask for alloc_coherent. */
71 dma_mask &= *dev->dma_mask;
73 /* Why <=? Even when the mask is smaller than 4GB it is often
74 larger than 16MB and in this case we have a chance of
75 finding fitting memory in the next higher zone first. If
76 not retry with true GFP_DMA. -AK */
77 if (dma_mask <= DMA_32BIT_MASK)
81 page = dma_alloc_pages(dev, gfp, get_order(size));
87 bus = page_to_phys(page);
88 memory = page_address(page);
89 high = (bus + size) >= dma_mask;
91 if (force_iommu && !(gfp & GFP_DMA))
94 free_pages((unsigned long)memory,
97 /* Don't use the 16MB ZONE_DMA unless absolutely
98 needed. It's better to use remapping first. */
99 if (dma_mask < DMA_32BIT_MASK && !(gfp & GFP_DMA)) {
100 gfp = (gfp & ~GFP_DMA32) | GFP_DMA;
104 /* Let low level make its own zone decisions */
105 gfp &= ~(GFP_DMA32|GFP_DMA);
107 if (dma_ops->alloc_coherent)
108 return dma_ops->alloc_coherent(dev, size,
113 memset(memory, 0, size);
120 if (dma_ops->alloc_coherent) {
121 free_pages((unsigned long)memory, get_order(size));
122 gfp &= ~(GFP_DMA|GFP_DMA32);
123 return dma_ops->alloc_coherent(dev, size, dma_handle, gfp);
126 if (dma_ops->map_simple) {
127 *dma_handle = dma_ops->map_simple(dev, virt_to_phys(memory),
129 PCI_DMA_BIDIRECTIONAL);
130 if (*dma_handle != bad_dma_address)
134 if (panic_on_overflow)
135 panic("dma_alloc_coherent: IOMMU overflow by %lu bytes\n",size);
136 free_pages((unsigned long)memory, get_order(size));
139 EXPORT_SYMBOL(dma_alloc_coherent);
142 * Unmap coherent memory.
143 * The caller must ensure that the device has finished accessing the mapping.
145 void dma_free_coherent(struct device *dev, size_t size,
146 void *vaddr, dma_addr_t bus)
148 int order = get_order(size);
149 WARN_ON(irqs_disabled()); /* for portability */
150 if (dma_release_coherent(dev, order, vaddr))
152 if (dma_ops->unmap_single)
153 dma_ops->unmap_single(dev, bus, size, 0);
154 free_pages((unsigned long)vaddr, order);
156 EXPORT_SYMBOL(dma_free_coherent);