Viewing file:  ip27-pci-dma.c (4.52 KB) -rw-r--r--
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/*
* Dynamic DMA mapping support.
*
* On the Origin there is dynamic DMA address translation for all PCI DMA.
* However we don't use this facility yet but rely on the 2gb direct
* mapped DMA window for PCI64. So consistent alloc/free are merely page
* allocation/freeing. The rest of the dynamic DMA mapping interface is
* implemented in <asm/pci.h>. So this code will fail with more than
* 2gb of memory.
*/
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/pci.h>
#include <asm/io.h>
/* Pure 2^n version of get_order */
extern __inline__ int __get_order(unsigned long size)
{
int order;
size = (size-1) >> (PAGE_SHIFT-1);
order = -1;
do {
size >>= 1;
order++;
} while (size);
return order;
}
void *pci_alloc_consistent(struct pci_dev *hwdev, size_t size,
dma_addr_t *dma_handle)
{
void *ret;
int gfp = GFP_ATOMIC;
int order = __get_order(size);
if (hwdev == NULL || hwdev->dma_mask != 0xffffffff)
gfp |= GFP_DMA;
ret = (void *)__get_free_pages(gfp, order);
if (ret != NULL) {
memset(ret, 0, size);
*dma_handle = (bus_to_baddr[hwdev->bus->number] | __pa(ret));
}
return ret;
}
void pci_free_consistent(struct pci_dev *hwdev, size_t size,
void *vaddr, dma_addr_t dma_handle)
{
free_pages((unsigned long)vaddr, __get_order(size));
}
/*
* Map a single buffer of the indicated size for DMA in streaming mode.
* The 32-bit bus address to use is returned.
*
* Once the device is given the dma address, the device owns this memory
* until either pci_unmap_single or pci_dma_sync_single is performed.
*/
dma_addr_t pci_map_single(struct pci_dev *hwdev, void *ptr, size_t size,
int direction)
{
if (direction == PCI_DMA_NONE)
BUG();
return (bus_to_baddr[hwdev->bus->number] | __pa(ptr));
}
/*
* Unmap a single streaming mode DMA translation. The dma_addr and size
* must match what was provided for in a previous pci_map_single call. All
* other usages are undefined.
*
* After this call, reads by the cpu to the buffer are guarenteed to see
* whatever the device wrote there.
*/
void pci_unmap_single(struct pci_dev *hwdev, dma_addr_t dma_addr,
size_t size, int direction)
{
if (direction == PCI_DMA_NONE)
BUG();
/* Nothing to do */
}
/*
* Map a set of buffers described by scatterlist in streaming
* mode for DMA. This is the scather-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 pci_map_sg(struct pci_dev *hwdev, struct scatterlist *sg, int nents,
int direction)
{
int i;
if (direction == PCI_DMA_NONE)
BUG();
/* Make sure that gcc doesn't leave the empty loop body. */
for (i = 0; i < nents; i++, sg++) {
sg->address = (char *)(bus_to_baddr[hwdev->bus->number] | __pa(sg->address));
}
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 pci_unmap_sg(struct pci_dev *hwdev, struct scatterlist *sg, int nents,
int direction)
{
if (direction == PCI_DMA_NONE)
BUG();
/* Nothing to do */
}
/*
* Make physical memory consistent for a single
* streaming mode DMA translation after a transfer.
*
* If you perform a pci_map_single() but wish to interrogate the
* buffer using the cpu, yet do not wish to teardown the PCI dma
* mapping, you must call this function before doing so. At the
* next point you give the PCI dma address back to the card, the
* device again owns the buffer.
*/
void pci_dma_sync_single(struct pci_dev *hwdev, dma_addr_t dma_handle,
size_t size, int direction)
{
if (direction == PCI_DMA_NONE)
BUG();
}
/*
* Make physical memory consistent for a set of streaming
* mode DMA translations after a transfer.
*
* The same as pci_dma_sync_single but for a scatter-gather list,
* same rules and usage.
*/
void pci_dma_sync_sg(struct pci_dev *hwdev, struct scatterlist *sg,
int nelems, int direction)
{
if (direction == PCI_DMA_NONE)
BUG();
}
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