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/*
* Dynamic DMA mapping support.
*/
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/pci.h>
#include <linux/module.h>
#include <linux/dmar.h>
#include <linux/bootmem.h>
#include <asm/proto.h>
#include <asm/io.h>
#include <asm/gart.h>
#include <asm/calgary.h>
/* Dummy device used for NULL arguments (normally ISA). Better would
be probably a smaller DMA mask, but this is bug-to-bug compatible
to i386. */
struct device fallback_dev = {
.bus_id = "fallback device",
.coherent_dma_mask = DMA_32BIT_MASK,
.dma_mask = &fallback_dev.coherent_dma_mask,
};
/* Allocate DMA memory on node near device */
noinline static void *
dma_alloc_pages(struct device *dev, gfp_t gfp, unsigned order)
{
int node;
node = dev_to_node(dev);
return alloc_pages_node(node, gfp, order);
}
#define dma_alloc_from_coherent_mem(dev, size, handle, ret) (0)
#define dma_release_coherent(dev, order, vaddr) (0)
/*
* Allocate memory for a coherent mapping.
*/
void *
dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle,
gfp_t gfp)
{
void *memory;
struct page *page;
unsigned long dma_mask = 0;
u64 bus;
/* ignore region specifiers */
gfp &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32);
if (dma_alloc_from_coherent_mem(dev, size, dma_handle, &memory))
return memory;
if (!dev)
dev = &fallback_dev;
dma_mask = dev->coherent_dma_mask;
if (dma_mask == 0)
dma_mask = DMA_32BIT_MASK;
/* Device not DMA able */
if (dev->dma_mask == NULL)
return NULL;
/* Don't invoke OOM killer */
gfp |= __GFP_NORETRY;
/* Why <=? Even when the mask is smaller than 4GB it is often
larger than 16MB and in this case we have a chance of
finding fitting memory in the next higher zone first. If
not retry with true GFP_DMA. -AK */
if (dma_mask <= DMA_32BIT_MASK)
gfp |= GFP_DMA32;
again:
page = dma_alloc_pages(dev, gfp, get_order(size));
if (page == NULL)
return NULL;
{
int high, mmu;
bus = page_to_phys(page);
memory = page_address(page);
high = (bus + size) >= dma_mask;
mmu = high;
if (force_iommu && !(gfp & GFP_DMA))
mmu = 1;
else if (high) {
free_pages((unsigned long)memory,
get_order(size));
/* Don't use the 16MB ZONE_DMA unless absolutely
needed. It's better to use remapping first. */
if (dma_mask < DMA_32BIT_MASK && !(gfp & GFP_DMA)) {
gfp = (gfp & ~GFP_DMA32) | GFP_DMA;
goto again;
}
/* Let low level make its own zone decisions */
gfp &= ~(GFP_DMA32|GFP_DMA);
if (dma_ops->alloc_coherent)
return dma_ops->alloc_coherent(dev, size,
dma_handle, gfp);
return NULL;
}
memset(memory, 0, size);
if (!mmu) {
*dma_handle = bus;
return memory;
}
}
if (dma_ops->alloc_coherent) {
free_pages((unsigned long)memory, get_order(size));
gfp &= ~(GFP_DMA|GFP_DMA32);
return dma_ops->alloc_coherent(dev, size, dma_handle, gfp);
}
if (dma_ops->map_simple) {
*dma_handle = dma_ops->map_simple(dev, virt_to_phys(memory),
size,
PCI_DMA_BIDIRECTIONAL);
if (*dma_handle != bad_dma_address)
return memory;
}
if (panic_on_overflow)
panic("dma_alloc_coherent: IOMMU overflow by %lu bytes\n",size);
free_pages((unsigned long)memory, get_order(size));
return NULL;
}
EXPORT_SYMBOL(dma_alloc_coherent);
/*
* Unmap coherent memory.
* The caller must ensure that the device has finished accessing the mapping.
*/
void dma_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t bus)
{
int order = get_order(size);
WARN_ON(irqs_disabled()); /* for portability */
if (dma_release_coherent(dev, order, vaddr))
return;
if (dma_ops->unmap_single)
dma_ops->unmap_single(dev, bus, size, 0);
free_pages((unsigned long)vaddr, order);
}
EXPORT_SYMBOL(dma_free_coherent);
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