iommu sg merging: PCI: add device_dma_parameters support

This adds struct device_dma_parameters in struct pci_dev and properly
sets up a pointer in struct device.

The default max_segment_size is set to 64K, same to the block layer's
default value.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Mostly-acked-by: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 20 insertions, 0 deletions

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 04aac7782468..be97090ddf32 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1451,6 +1451,14 @@ pci_set_consistent_dma_mask(struct pci_dev *dev, u64 mask)
 }
 #endif
 
+#ifndef HAVE_ARCH_PCI_SET_DMA_MAX_SEGMENT_SIZE
+int pci_set_dma_max_seg_size(struct pci_dev *dev, unsigned int size)
+{
+        return dma_set_max_seg_size(&dev->dev, size);
+}
+EXPORT_SYMBOL(pci_set_dma_max_seg_size);
+#endif
+
 /**
  * pcix_get_max_mmrbc - get PCI-X maximum designed memory read byte count
  * @dev: PCI device to query
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 7f5dab34d315..f47d596d5ebc 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -933,8 +933,11 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
 
         set_dev_node(&dev->dev, pcibus_to_node(bus));
         dev->dev.dma_mask = &dev->dma_mask;
+        dev->dev.dma_parms = &dev->dma_parms;
         dev->dev.coherent_dma_mask = 0xffffffffull;
 
+        pci_set_dma_max_seg_size(dev, 65536);
+
         /* Fix up broken headers */
         pci_fixup_device(pci_fixup_header, dev);
 
diff --git a/include/linux/pci.h b/include/linux/pci.h
index cee75c0ff6e7..ba3a7f459da4 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -159,6 +159,8 @@ struct pci_dev {
                                            this if your device has broken DMA
                                            or supports 64-bit transfers.  */
 
+        struct device_dma_parameters dma_parms;
+
         pci_power_t     current_state;  /* Current operating state. In ACPI-speak,
                                            this is D0-D3, D0 being fully functional,
                                            and D3 being off. */
@@ -580,6 +582,7 @@ void pci_intx(struct pci_dev *dev, int enable);
 void pci_msi_off(struct pci_dev *dev);
 int pci_set_dma_mask(struct pci_dev *dev, u64 mask);
 int pci_set_consistent_dma_mask(struct pci_dev *dev, u64 mask);
+int pci_set_dma_max_seg_size(struct pci_dev *dev, unsigned int size);
 int pcix_get_max_mmrbc(struct pci_dev *dev);
 int pcix_get_mmrbc(struct pci_dev *dev);
 int pcix_set_mmrbc(struct pci_dev *dev, int mmrbc);
@@ -822,6 +825,12 @@ static inline int pci_set_dma_mask(struct pci_dev *dev, u64 mask)
         return -EIO;
 }
 
+static inline int pci_set_dma_max_seg_size(struct pci_dev *dev,
+                                        unsigned int size)
+{
+        return -EIO;
+}
+
 static inline int pci_assign_resource(struct pci_dev *dev, int i)
 {
         return -EBUSY;