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linux-next/arch/x86/kernel/pci-nommu.c
Arnd Bergmann a8ad568dd8 dma-ops: Remove flush_write_buffers() in dma-mapping-common.h
This moves flush_write_buffers() in
asm-generic/dma-mapping-common.h to
arch/x86/kernel/pci-nommu.c.

The purpose of this patch is that, we can avoid defining NULL
flush_write_buffers() on IA64 and SPARC.

dma-mapping-common.h is used by X86 and IA64 (and SPARC soon)
but only X86 with CONFIG_X86_OOSTORE or CONFIG_X86_PPRO_FENCE
actually uses flush_write_buffers(). CONFIG_X86_OOSTORE or
CONFIG_X86_PPRO_FENCE is usable with only kernel/pci-nommu.c
(that is, not usable with other X86 IOMMU implementations such
as SWIOTLB, VT-d, etc) so we can safely move
flush_write_buffers() in asm-generic/dma-mapping-common.h to
arch/x86/kernel/pci-nommu.c.

The further discussion is:

  http://lkml.org/lkml/2009/6/28/104

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: davem@davemloft.net
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
LKML-Reference: <1249872797-1314-2-git-send-email-fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-10 09:34:57 +02:00

115 lines
3.0 KiB
C

/* Fallback functions when the main IOMMU code is not compiled in. This
code is roughly equivalent to i386. */
#include <linux/dma-mapping.h>
#include <linux/scatterlist.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/mm.h>
#include <asm/processor.h>
#include <asm/iommu.h>
#include <asm/dma.h>
static int
check_addr(char *name, struct device *hwdev, dma_addr_t bus, size_t size)
{
if (hwdev && !dma_capable(hwdev, bus, size)) {
if (*hwdev->dma_mask >= DMA_BIT_MASK(32))
printk(KERN_ERR
"nommu_%s: overflow %Lx+%zu of device mask %Lx\n",
name, (long long)bus, size,
(long long)*hwdev->dma_mask);
return 0;
}
return 1;
}
static dma_addr_t nommu_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction dir,
struct dma_attrs *attrs)
{
dma_addr_t bus = page_to_phys(page) + offset;
WARN_ON(size == 0);
if (!check_addr("map_single", dev, bus, size))
return bad_dma_address;
flush_write_buffers();
return bus;
}
/* Map a set of buffers described by scatterlist in streaming
* mode for DMA. This is the scatter-gather version of the
* above pci_map_single interface. Here the scatter gather list
* elements are each tagged with the appropriate dma address
* and length. They are obtained via sg_dma_{address,length}(SG).
*
* NOTE: An implementation may be able to use a smaller number of
* DMA address/length pairs than there are SG table elements.
* (for example via virtual mapping capabilities)
* The routine returns the number of addr/length pairs actually
* used, at most nents.
*
* Device ownership issues as mentioned above for pci_map_single are
* the same here.
*/
static int nommu_map_sg(struct device *hwdev, struct scatterlist *sg,
int nents, enum dma_data_direction dir,
struct dma_attrs *attrs)
{
struct scatterlist *s;
int i;
WARN_ON(nents == 0 || sg[0].length == 0);
for_each_sg(sg, s, nents, i) {
BUG_ON(!sg_page(s));
s->dma_address = sg_phys(s);
if (!check_addr("map_sg", hwdev, s->dma_address, s->length))
return 0;
s->dma_length = s->length;
}
flush_write_buffers();
return nents;
}
static void nommu_free_coherent(struct device *dev, size_t size, void *vaddr,
dma_addr_t dma_addr)
{
free_pages((unsigned long)vaddr, get_order(size));
}
static void nommu_sync_single_for_device(struct device *dev,
dma_addr_t addr, size_t size,
enum dma_data_direction dir)
{
flush_write_buffers();
}
static void nommu_sync_sg_for_device(struct device *dev,
struct scatterlist *sg, int nelems,
enum dma_data_direction dir)
{
flush_write_buffers();
}
struct dma_map_ops nommu_dma_ops = {
.alloc_coherent = dma_generic_alloc_coherent,
.free_coherent = nommu_free_coherent,
.map_sg = nommu_map_sg,
.map_page = nommu_map_page,
.sync_single_for_device = nommu_sync_single_for_device,
.sync_sg_for_device = nommu_sync_sg_for_device,
.is_phys = 1,
};
void __init no_iommu_init(void)
{
if (dma_ops)
return;
force_iommu = 0; /* no HW IOMMU */
dma_ops = &nommu_dma_ops;
}