2 files changed, 59 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);
+}
diff --git a/include/linux/pci.h b/include/linux/pci.h
index d8c379dba6ad..39983be7b25b 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1332,6 +1332,9 @@ static inline struct pci_dev *pci_get_bus_and_slot(unsigned int bus,
 static inline int pci_domain_nr(struct pci_bus *bus)
 { return 0; }
 
+static inline struct pci_dev *pci_dev_get(struct pci_dev *dev)
+{ return NULL; }
+
 #define dev_is_pci(d) (false)
 #define dev_is_pf(d) (false)
 #define dev_num_vf(d) (0)
@@ -1486,9 +1489,14 @@ enum pci_fixup_pass {
 
 #ifdef CONFIG_PCI_QUIRKS
 void pci_fixup_device(enum pci_fixup_pass pass, struct pci_dev *dev);
+struct pci_dev *pci_get_dma_source(struct pci_dev *dev);
 #else
 static inline void pci_fixup_device(enum pci_fixup_pass pass,
                                     struct pci_dev *dev) {}
+static inline struct pci_dev *pci_get_dma_source(struct pci_dev *dev)
+{
+        return pci_dev_get(dev);
+}
 #endif
 
 void __iomem *pcim_iomap(struct pci_dev *pdev, int bar, unsigned long maxlen);