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linux-next/arch/x86/kernel/pci-swiotlb_64.c
FUJITA Tomonori 03967c5267 x86: restore the old swiotlb alloc_coherent behavior
This restores the old swiotlb alloc_coherent behavior (before the
alloc_coherent rewrite):

  http://lkml.org/lkml/2008/8/12/200

The old alloc_coherent avoids GFP_DMA allocation first and if the
allocated address is not fit for the device's coherent_dma_mask, then
dma_alloc_coherent does GFP_DMA allocation. If it fails,
alloc_coherent calls swiotlb_alloc_coherent (in short, we rarely used
swiotlb_alloc_coherent).

After the alloc_coherent rewrite, dma_alloc_coherent
(include/asm-x86/dma-mapping.h) directly calls swiotlb_alloc_coherent.
It means that we possibly can't handle a device having dma_masks >
24bit < 32bits since swiotlb_alloc_coherent doesn't have the above
GFP_DMA retry mechanism.

This patch fixes x86's swiotlb alloc_coherent to use the GFP_DMA retry
mechanism, which dma_generic_alloc_coherent() provides now
(pci-nommu.c and GART IOMMU driver also use
dma_generic_alloc_coherent).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-23 21:54:40 +02:00

63 lines
1.7 KiB
C

/* Glue code to lib/swiotlb.c */
#include <linux/pci.h>
#include <linux/cache.h>
#include <linux/module.h>
#include <linux/dma-mapping.h>
#include <asm/iommu.h>
#include <asm/swiotlb.h>
#include <asm/dma.h>
int swiotlb __read_mostly;
static dma_addr_t
swiotlb_map_single_phys(struct device *hwdev, phys_addr_t paddr, size_t size,
int direction)
{
return swiotlb_map_single(hwdev, phys_to_virt(paddr), size, direction);
}
static void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
dma_addr_t *dma_handle, gfp_t flags)
{
void *vaddr;
vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags);
if (vaddr)
return vaddr;
return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
}
struct dma_mapping_ops swiotlb_dma_ops = {
.mapping_error = swiotlb_dma_mapping_error,
.alloc_coherent = x86_swiotlb_alloc_coherent,
.free_coherent = swiotlb_free_coherent,
.map_single = swiotlb_map_single_phys,
.unmap_single = swiotlb_unmap_single,
.sync_single_for_cpu = swiotlb_sync_single_for_cpu,
.sync_single_for_device = swiotlb_sync_single_for_device,
.sync_single_range_for_cpu = swiotlb_sync_single_range_for_cpu,
.sync_single_range_for_device = swiotlb_sync_single_range_for_device,
.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
.sync_sg_for_device = swiotlb_sync_sg_for_device,
.map_sg = swiotlb_map_sg,
.unmap_sg = swiotlb_unmap_sg,
.dma_supported = NULL,
};
void __init pci_swiotlb_init(void)
{
/* don't initialize swiotlb if iommu=off (no_iommu=1) */
if (!iommu_detected && !no_iommu && max_pfn > MAX_DMA32_PFN)
swiotlb = 1;
if (swiotlb_force)
swiotlb = 1;
if (swiotlb) {
printk(KERN_INFO "PCI-DMA: Using software bounce buffering for IO (SWIOTLB)\n");
swiotlb_init();
dma_ops = &swiotlb_dma_ops;
}
}