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authorBin Meng <bmeng.cn@gmail.com>2015-10-01 00:36:02 -0700
committerSimon Glass <sjg@chromium.org>2015-10-21 07:46:25 -0600
commitbbbcb5262839e19fa4c327e1797db08468fc6743 (patch)
tree496efda53b1c41eda2eb30741cb6acf30fa24962 /drivers
parent069155cbb44c1e9e45676ac64e3c95f76a8d5820 (diff)
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dm: pci: Enable VGA address forwarding on bridges
To support graphics card behind a PCI bridge, the bridge control register (offset 0x3e) in the configuration space must turn on VGA address forwarding. Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Acked-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/pci/pci-uclass.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c
index d15de5a..1d93194 100644
--- a/drivers/pci/pci-uclass.c
+++ b/drivers/pci/pci-uclass.c
@@ -364,9 +364,23 @@ int dm_pci_read_config32(struct udevice *dev, int offset, u32 *valuep)
return 0;
}
+static void set_vga_bridge_bits(struct udevice *dev)
+{
+ struct udevice *parent = dev->parent;
+ u16 bc;
+
+ while (parent->seq != 0) {
+ dm_pci_read_config16(parent, PCI_BRIDGE_CONTROL, &bc);
+ bc |= PCI_BRIDGE_CTL_VGA;
+ dm_pci_write_config16(parent, PCI_BRIDGE_CONTROL, bc);
+ parent = parent->parent;
+ }
+}
+
int pci_auto_config_devices(struct udevice *bus)
{
struct pci_controller *hose = bus->uclass_priv;
+ struct pci_child_platdata *pplat;
unsigned int sub_bus;
struct udevice *dev;
int ret;
@@ -386,6 +400,10 @@ int pci_auto_config_devices(struct udevice *bus)
return ret;
max_bus = ret;
sub_bus = max(sub_bus, max_bus);
+
+ pplat = dev_get_parent_platdata(dev);
+ if (pplat->class == (PCI_CLASS_DISPLAY_VGA << 8))
+ set_vga_bridge_bits(dev);
}
debug("%s: done\n", __func__);