9f9ab46d55
This patch implements mapping_error for pci-nommu_64.c. It takes care to keep the same compatible behaviour it already had. Although this file is not (yet) used for i386, we introduce the i386 version here. Again, care is taken, even at the expense of an ifdef, to keep the same behaviour inconditionally. Signed-off-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
96 lines
2.4 KiB
C
96 lines
2.4 KiB
C
/* Fallback functions when the main IOMMU code is not compiled in. This
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code is roughly equivalent to i386. */
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#include <linux/mm.h>
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#include <linux/init.h>
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#include <linux/pci.h>
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#include <linux/string.h>
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#include <linux/dma-mapping.h>
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#include <linux/scatterlist.h>
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#include <asm/gart.h>
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#include <asm/processor.h>
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#include <asm/dma.h>
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static int
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check_addr(char *name, struct device *hwdev, dma_addr_t bus, size_t size)
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{
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if (hwdev && bus + size > *hwdev->dma_mask) {
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if (*hwdev->dma_mask >= DMA_32BIT_MASK)
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printk(KERN_ERR
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"nommu_%s: overflow %Lx+%zu of device mask %Lx\n",
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name, (long long)bus, size,
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(long long)*hwdev->dma_mask);
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return 0;
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}
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return 1;
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}
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static dma_addr_t
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nommu_map_single(struct device *hwdev, phys_addr_t paddr, size_t size,
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int direction)
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{
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dma_addr_t bus = paddr;
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if (!check_addr("map_single", hwdev, bus, size))
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return bad_dma_address;
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return bus;
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}
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/* Map a set of buffers described by scatterlist in streaming
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* mode for DMA. This is the scatter-gather version of the
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* above pci_map_single interface. Here the scatter gather list
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* elements are each tagged with the appropriate dma address
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* and length. They are obtained via sg_dma_{address,length}(SG).
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*
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* NOTE: An implementation may be able to use a smaller number of
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* DMA address/length pairs than there are SG table elements.
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* (for example via virtual mapping capabilities)
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* The routine returns the number of addr/length pairs actually
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* used, at most nents.
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*
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* Device ownership issues as mentioned above for pci_map_single are
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* the same here.
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*/
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static int nommu_map_sg(struct device *hwdev, struct scatterlist *sg,
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int nents, int direction)
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{
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struct scatterlist *s;
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int i;
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for_each_sg(sg, s, nents, i) {
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BUG_ON(!sg_page(s));
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s->dma_address = virt_to_bus(sg_virt(s));
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if (!check_addr("map_sg", hwdev, s->dma_address, s->length))
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return 0;
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s->dma_length = s->length;
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}
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return nents;
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}
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/* Make sure we keep the same behaviour */
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static int nommu_mapping_error(dma_addr_t dma_addr)
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{
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#ifdef CONFIG_X86_32
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return 0;
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#else
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return (dma_addr == bad_dma_address);
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#endif
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}
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const struct dma_mapping_ops nommu_dma_ops = {
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.map_single = nommu_map_single,
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.map_sg = nommu_map_sg,
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.mapping_error = nommu_mapping_error,
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.is_phys = 1,
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};
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void __init no_iommu_init(void)
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{
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if (dma_ops)
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return;
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force_iommu = 0; /* no HW IOMMU */
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dma_ops = &nommu_dma_ops;
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}
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