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 ---
drivers/pci/pci-uclass.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)
diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c index 0035ac7..7b01a13 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; @@ -382,6 +396,10 @@ int pci_auto_config_devices(struct udevice *bus) debug("%s: device %s\n", __func__, dev->name); max_bus = pciauto_config_device(hose, pci_get_bdf(dev)); 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__);