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Subject[RFC PATCH 2/2] PCI: get device dma configuration from parent
Date
This patch makes use of the helper function dma_get_parent_cfg() to
get dma configuration from the parent of the root bus bridge device.
One particular comfiguration that is required for Keystone PCI devices
to function correctly is the dma_pfn_offset that has to be correctly
set in the pci device's device structure in order for getting the
dma_mask right for the device.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
---
drivers/pci/probe.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index c8ca98c..8f4d55b 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1519,6 +1519,8 @@ static void pci_init_capabilities(struct pci_dev *dev)

void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
{
+ struct pci_bus *temp_bus = bus;
+ struct device *parent;
int ret;

pci_configure_device(dev);
@@ -1527,9 +1529,21 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
dev->dev.release = pci_release_dev;

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;
+ /*
+ * look for host bridge and check if the dma parameters
+ * can be copied from parent
+ */
+ while (!pci_is_root_bus(temp_bus))
+ temp_bus = temp_bus->parent;
+
+ parent = temp_bus->bridge->parent;
+
+ /* override with parent dma configuration if available */
+ if (dma_get_parent_cfg(&dev->dev, parent) < 0) {
+ 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);
pci_set_dma_seg_boundary(dev, 0xffffffff);
--
1.7.9.5


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