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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/x86/kernel/pci-nommu.c
Initial import
Diffstat (limited to 'arch/x86/kernel/pci-nommu.c')
-rw-r--r--arch/x86/kernel/pci-nommu.c99
1 files changed, 99 insertions, 0 deletions
diff --git a/arch/x86/kernel/pci-nommu.c b/arch/x86/kernel/pci-nommu.c
new file mode 100644
index 000000000..da15918d1
--- /dev/null
+++ b/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,
+};