diff options
Diffstat (limited to 'kernel/arch/x86/kernel/pci-nommu.c')
-rw-r--r-- | kernel/arch/x86/kernel/pci-nommu.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/kernel/arch/x86/kernel/pci-nommu.c b/kernel/arch/x86/kernel/pci-nommu.c new file mode 100644 index 000000000..da15918d1 --- /dev/null +++ b/kernel/arch/x86/kernel/pci-nommu.c @@ -0,0 +1,99 @@ +/* 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/gfp.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 DMA_ERROR_CODE; + 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_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 = dma_generic_alloc_coherent, + .free = dma_generic_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, +}; |