From bbbcb5262839e19fa4c327e1797db08468fc6743 Mon Sep 17 00:00:00 2001 From: Bin Meng Date: Thu, 1 Oct 2015 00:36:02 -0700 Subject: 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 Acked-by: Simon Glass --- drivers/pci/pci-uclass.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'drivers/pci/pci-uclass.c') diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c index d15de5ab37..1d93194b67 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__); -- cgit v1.2.3