PCI/portdrv: Support PCIe services on subtractive decode bridges

task #29600094

commit f0cfecea8d1e8e0cd5d5053f9452b3a450f49eb5 upstream.
Backport summary: for 4.19 kernel ICX PCIe Gen4 support.

The Class Code for subtractive decode PCI-to-PCI bridge is 060401h; add an
entry to make portdrv support this type of bridge.  This allows use of PCIe
services on subtractive decode ports.
Signed-off-by: NHonghui Zhang <honghui.zhang@mediatek.com>
[bhelgaas: add braces surrounding entry]
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
(cherry picked from commit f0cfecea8d1e8e0cd5d5053f9452b3a450f49eb5)
Signed-off-by: NEthan Zhao <haifeng.zhao@intel.com>
Signed-off-by: NArtie Ding <artie.ding@linux.alibaba.com>
Acked-by: NCaspar Zhang <caspar@linux.alibaba.com>

drivers/pci/pcie/portdrv_pci.c

@@ -180,6 +180,8 @@ static void pcie_portdrv_err_resume(struct pci_dev *dev)
 static const struct pci_device_id port_pci_ids[] = {
 	/* handle any PCI-Express port */
 	{ PCI_DEVICE_CLASS(((PCI_CLASS_BRIDGE_PCI << 8) | 0x00), ~0) },
+	/* subtractive decode PCI-to-PCI bridge, class type is 060401h */
+	{ PCI_DEVICE_CLASS(((PCI_CLASS_BRIDGE_PCI << 8) | 0x01), ~0) },
 	{ },
 };