1 files changed, 51 insertions, 0 deletions
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 2a7521677541..acd3956b44bd 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3179,3 +3179,54 @@ int pci_dev_specific_reset(struct pci_dev *dev, int probe)
 
 	return -ENOTTY;
 }
+
+static struct pci_dev *pci_func_0_dma_source(struct pci_dev *dev)
+{
+	if (!PCI_FUNC(dev->devfn))
+		return pci_dev_get(dev);
+
+	return pci_get_slot(dev->bus, PCI_DEVFN(PCI_SLOT(dev->devfn), 0));
+}
+
+static const struct pci_dev_dma_source {
+	u16 vendor;
+	u16 device;
+	struct pci_dev *(*dma_source)(struct pci_dev *dev);
+} pci_dev_dma_source[] = {
+	/*
+	 * https://bugzilla.redhat.com/show_bug.cgi?id=605888
+	 *
+	 * Some Ricoh devices use the function 0 source ID for DMA on
+	 * other functions of a multifunction device.  The DMA devices
+	 * is therefore function 0, which will have implications of the
+	 * iommu grouping of these devices.
+	 */
+	{ PCI_VENDOR_ID_RICOH, 0xe822, pci_func_0_dma_source },
+	{ PCI_VENDOR_ID_RICOH, 0xe230, pci_func_0_dma_source },
+	{ PCI_VENDOR_ID_RICOH, 0xe832, pci_func_0_dma_source },
+	{ PCI_VENDOR_ID_RICOH, 0xe476, pci_func_0_dma_source },
+	{ 0 }
+};
+
+/*
+ * IOMMUs with isolation capabilities need to be programmed with the
+ * correct source ID of a device.  In most cases, the source ID matches
+ * the device doing the DMA, but sometimes hardware is broken and will
+ * tag the DMA as being sourced from a different device.  This function
+ * allows that translation.  Note that the reference count of the
+ * returned device is incremented on all paths.
+ */
+struct pci_dev *pci_get_dma_source(struct pci_dev *dev)
+{
+	const struct pci_dev_dma_source *i;
+
+	for (i = pci_dev_dma_source; i->dma_source; i++) {
+		if ((i->vendor == dev->vendor ||
+		     i->vendor == (u16)PCI_ANY_ID) &&
+		    (i->device == dev->device ||
+		     i->device == (u16)PCI_ANY_ID))
+			return i->dma_source(dev);
+	}
+
+	return pci_dev_get(dev);
+}