93 lines
2.5 KiB
C
93 lines
2.5 KiB
C
/* Fallback functions when the main IOMMU code is not compiled in. This
|
|
code is roughly equivalent to i386. */
|
|
#include <linux/mm.h>
|
|
#include <linux/init.h>
|
|
#include <linux/pci.h>
|
|
#include <linux/string.h>
|
|
#include <asm/proto.h>
|
|
#include <asm/processor.h>
|
|
#include <asm/dma.h>
|
|
|
|
static int
|
|
check_addr(char *name, struct device *hwdev, dma_addr_t bus, size_t size)
|
|
{
|
|
if (hwdev && bus + size > *hwdev->dma_mask) {
|
|
printk(KERN_ERR
|
|
"nommu_%s: overflow %Lx+%lu 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_single(struct device *hwdev, void *ptr, size_t size,
|
|
int direction)
|
|
{
|
|
dma_addr_t bus = virt_to_bus(ptr);
|
|
if (!check_addr("map_single", hwdev, bus, size))
|
|
return bad_dma_address;
|
|
return bus;
|
|
}
|
|
|
|
void nommu_unmap_single(struct device *dev, dma_addr_t addr,size_t size,
|
|
int direction)
|
|
{
|
|
}
|
|
|
|
/* 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.
|
|
*/
|
|
int nommu_map_sg(struct device *hwdev, struct scatterlist *sg,
|
|
int nents, int direction)
|
|
{
|
|
int i;
|
|
|
|
BUG_ON(direction == DMA_NONE);
|
|
for (i = 0; i < nents; i++ ) {
|
|
struct scatterlist *s = &sg[i];
|
|
BUG_ON(!s->page);
|
|
s->dma_address = virt_to_bus(page_address(s->page) +s->offset);
|
|
if (!check_addr("map_sg", hwdev, s->dma_address, s->length))
|
|
return 0;
|
|
s->dma_length = s->length;
|
|
}
|
|
return nents;
|
|
}
|
|
|
|
/* Unmap a set of streaming mode DMA translations.
|
|
* Again, cpu read rules concerning calls here are the same as for
|
|
* pci_unmap_single() above.
|
|
*/
|
|
void nommu_unmap_sg(struct device *dev, struct scatterlist *sg,
|
|
int nents, int dir)
|
|
{
|
|
}
|
|
|
|
struct dma_mapping_ops nommu_dma_ops = {
|
|
.map_single = nommu_map_single,
|
|
.unmap_single = nommu_unmap_single,
|
|
.map_sg = nommu_map_sg,
|
|
.unmap_sg = nommu_unmap_sg,
|
|
.is_phys = 1,
|
|
};
|
|
|
|
void __init no_iommu_init(void)
|
|
{
|
|
if (dma_ops)
|
|
return;
|
|
dma_ops = &nommu_dma_ops;
|
|
}
|