[PATCH v8 6/7] PCI: Update DMA configuration from DT

Murali Karicheri m-karicheri2 at ti.com
Tue Mar 3 09:52:13 PST 2015

If there is a DT node available for the root bridge's parent device, use
the DMA configuration from that device node.  For example, Keystone PCI
devices would require dma_pfn_offset to be set correctly in the device
structure of the PCI device in order to have the correct DMA mask.  The DT
node will have dma-ranges defined for this.  Also support using the DT
property dma-coherent to allow coherent DMA operation by the PCI device.

Use the new helper function of_pci_dma_configure() to update the device DMA
configuration.  This fixes DMA on systems where DMA addresses are a
constant offset from CPU physical addresses.

Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit at amd.com> (AMD Seattle)
Signed-off-by: Murali Karicheri <m-karicheri2 at ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
Reviewed-by: Catalin Marinas <catalin.marinas at arm.com>
Acked-by: Will Deacon <will.deacon at arm.com>
CC: Joerg Roedel <joro at 8bytes.org>
CC: Grant Likely <grant.likely at linaro.org>
CC: Rob Herring <robh+dt at kernel.org>
CC: Russell King <linux at arm.linux.org.uk>
CC: Arnd Bergmann <arnd at arndb.de>
 drivers/pci/probe.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 8d2f400..413c1dd 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -6,6 +6,7 @@
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/pci.h>
+#include <linux/of_pci.h>
 #include <linux/pci_hotplug.h>
 #include <linux/slab.h>
 #include <linux/module.h>
@@ -1520,6 +1521,7 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
 	dev->dev.dma_mask = &dev->dma_mask;
 	dev->dev.dma_parms = &dev->dma_parms;
 	dev->dev.coherent_dma_mask = 0xffffffffull;
+	of_pci_dma_configure(dev);
 	pci_set_dma_max_seg_size(dev, 65536);
 	pci_set_dma_seg_boundary(dev, 0xffffffff);

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