From: Hou Zhiqiang Zhiqiang.Hou@nxp.com
As the PCIe specification recommend reading the Vendor ID register to determine if a Function is present, read the Vendor ID of a non-existent Function must not result in system error, so we'd better make the first CFG read to Vendor ID instead of Header Type register in the PCIe enumeration.
Signed-off-by: Hou Zhiqiang Zhiqiang.Hou@nxp.com --- drivers/pci/pci-uclass.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c index eb118f3496..c8cb9cdad9 100644 --- a/drivers/pci/pci-uclass.c +++ b/drivers/pci/pci-uclass.c @@ -748,16 +748,19 @@ int pci_bind_bus_devices(struct udevice *bus) found_multi = false; if (PCI_FUNC(bdf) && !found_multi) continue; + /* Check only the first access, we don't expect problems */ - ret = pci_bus_read_config(bus, bdf, PCI_HEADER_TYPE, - &header_type, PCI_SIZE_8); + ret = pci_bus_read_config(bus, bdf, PCI_VENDOR_ID, &vendor, + PCI_SIZE_16); if (ret) goto error; - pci_bus_read_config(bus, bdf, PCI_VENDOR_ID, &vendor, - PCI_SIZE_16); + if (vendor == 0xffff || vendor == 0x0000) continue;
+ pci_bus_read_config(bus, bdf, PCI_HEADER_TYPE, + &header_type, PCI_SIZE_8); + if (!PCI_FUNC(bdf)) found_multi = header_type & 0x80;