vserver 1.9.3

[linux-2.6.git] / arch / alpha / kernel / pci_iommu.c

diff --git a/arch/alpha/kernel/pci_iommu.c b/arch/alpha/kernel/pci_iommu.c
index b47c356..7cb23f1 100644 (file)
--- a/arch/alpha/kernel/pci_iommu.c
+++ b/arch/alpha/kernel/pci_iommu.c
@@ -930,3 +930,42 @@ pci_dac_dma_to_offset(struct pci_dev *pdev, dma64_addr_t dma_addr)
 {
        return (dma_addr & ~PAGE_MASK);
 }
+
+
+/* Helper for generic DMA-mapping functions. */
+
+struct pci_dev *
+alpha_gendev_to_pci(struct device *dev)
+{
+       if (dev && dev->bus == &pci_bus_type)
+               return to_pci_dev(dev);
+
+       /* Assume that non-PCI devices asking for DMA are either ISA or EISA,
+          BUG() otherwise. */
+       BUG_ON(!isa_bridge);
+
+       /* Assume non-busmaster ISA DMA when dma_mask is not set (the ISA
+          bridge is bus master then). */
+       if (!dev || !dev->dma_mask || !*dev->dma_mask)
+               return isa_bridge;
+
+       /* For EISA bus masters, return isa_bridge (it might have smaller
+          dma_mask due to wiring limitations). */
+       if (*dev->dma_mask >= isa_bridge->dma_mask)
+               return isa_bridge;
+
+       /* This assumes ISA bus master with dma_mask 0xffffff. */
+       return NULL;
+}
+
+int
+dma_set_mask(struct device *dev, u64 mask)
+{
+       if (!dev->dma_mask ||
+           !pci_dma_supported(alpha_gendev_to_pci(dev), mask))
+               return -EIO;
+
+       *dev->dma_mask = mask;
+
+       return 0;
+}