PCI: Add function 0 DMA alias quirk for Ricoh devices

The existing quirk for these devices (pci_get_dma_source()) doesn't really
solve the problem; re-implement it using the DMA alias iterator.  We'll
come back later and remove the existing quirk and dma_source interface.
Note that device ID 0xe822 is typically function 0 and 0xe230 has been
tested to not need the quirk and are therefore removed versus the
equivalent dma_source quirk.  If there exist in other configurations we can
re-add them.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=605888
Tested-by: Pat Erley <pat-lkml@erley.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Author: Alex Williamson

drivers/pci/quirks.c

@@ -3333,6 +3333,22 @@ int pci_dev_specific_reset(struct pci_dev *dev, int probe)
 	return -ENOTTY;
 }
 
+static void quirk_dma_func0_alias(struct pci_dev *dev)
+{
+	if (PCI_FUNC(dev->devfn) != 0) {
+		dev->dma_alias_devfn = PCI_DEVFN(PCI_SLOT(dev->devfn), 0);
+		dev->dev_flags |= PCI_DEV_FLAGS_DMA_ALIAS_DEVFN;
+	}
+}
+
+/*
+ * https://bugzilla.redhat.com/show_bug.cgi?id=605888
+ *
+ * Some Ricoh devices use function 0 as the PCIe requester ID for DMA.
+ */
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_RICOH, 0xe832, quirk_dma_func0_alias);
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_RICOH, 0xe476, quirk_dma_func0_alias);
+
 static struct pci_dev *pci_func_0_dma_source(struct pci_dev *dev)
 {
 	if (!PCI_FUNC(dev->devfn))