patch-2.4.20 linux-2.4.20/arch/x86_64/kernel/pci-dma.c
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- Lines: 75
- Date:
Thu Nov 28 15:53:12 2002
- Orig file:
linux-2.4.19/arch/x86_64/kernel/pci-dma.c
- Orig date:
Wed Dec 31 16:00:00 1969
diff -urN linux-2.4.19/arch/x86_64/kernel/pci-dma.c linux-2.4.20/arch/x86_64/kernel/pci-dma.c
@@ -0,0 +1,74 @@
+/*
+ * Dynamic DMA mapping support. Common code
+ */
+
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/pci.h>
+#include <asm/io.h>
+
+dma_addr_t bad_dma_address = -1UL;
+
+/* 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;
+
+ BUG_ON(direction == PCI_DMA_NONE);
+
+ /*
+ * temporary 2.4 hack
+ */
+ for (i = 0; i < nents; i++ ) {
+ struct scatterlist *s = &sg[i];
+ if (s->address) {
+ BUG_ON(s->page || s->offset);
+ s->dma_address = pci_map_single(hwdev, s->address, s->length,
+ direction);
+ } else if (s->page) {
+ s->dma_address = pci_map_page(hwdev, s->page, s->offset,
+ s->length, direction);
+ } else
+ BUG();
+
+ if (unlikely(s->dma_address == bad_dma_address))
+ goto error;
+ }
+ return nents;
+
+ error:
+ pci_unmap_sg(hwdev, sg, i, direction);
+ return 0;
+}
+
+/* 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 *dev, struct scatterlist *sg,
+ int nents, int dir)
+{
+ int i;
+ for (i = 0; i < nents; i++) {
+ struct scatterlist *s = &sg[i];
+ BUG_ON(s->address == NULL && s->page == NULL);
+ BUG_ON(s->dma_address == 0);
+ pci_unmap_single(dev, s->dma_address, s->length, dir);
+ }
+}
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