hi3531a pcie调试-io设备资源分配失败

最近在调试hi3531a的PCIE， PCIE外接的是PCIE转串口芯片(CH384L)，内核在分配PCIE mem资源时正常，但是分配IO资源时会失败。不知大家是否有遇到过呢？
Number of PCIe controllers: 2
PCI host bridge to bus 0000:00
pci_bus 0000:00: root bus resource [io 0x0000]
pci_bus 0000:00: root bus resource [mem 0x28000000-0x2fffffff]
pci_bus 0000:00: No busn resource found for root bus, will use [bus 00-ff]
PCI: bus0: Fast back to back transfers disabled
pci 0000:00:00.0: bridge configuration invalid ([bus 00-00]), reconfiguring
PCI: bus1: Fast back to back transfers disabled
PCI host bridge to bus 0000:02
pci_bus 0000:02: root bus resource [io 0x0001]
pci_bus 0000:02: root bus resource [mem 0x38000000-0x3fffffff]
pci_bus 0000:02: No busn resource found for root bus, will use [bus 02-ff]
PCI: bus2: Fast back to back transfers disabled
pci 0000:02:00.0: bridge configuration invalid ([bus 00-00]), reconfiguring
PCI: bus3: Fast back to back transfers enabled
pci 0000:02:00.0: BAR 0: assigned [mem 0x38000000-0x387fffff pref]
pci 0000:02:00.0: BAR 1: assigned [mem 0x38800000-0x3880ffff]
pci 0000:02:00.0: PCI bridge to [bus 03]
pci 0000:00:00.0: BAR 0: assigned [mem 0x28000000-0x287fffff pref]
pci 0000:00:00.0: BAR 9: assigned [mem 0x28800000-0x288fffff pref]
pci 0000:00:00.0: BAR 1: assigned [mem 0x28900000-0x2890ffff]
pci 0000:00:00.0: BAR 7: can’t assign io (size 0x1000)
pci 0000:01:00.0: BAR 1: assigned [mem 0x28800000-0x28807fff pref]
pci 0000:01:00.0: BAR 6: assigned [mem 0x28808000-0x2880ffff pref]
pci 0000:01:00.0: BAR 0: can’t assign io (size 0x100)
pci 0000:01:00.0: BAR 2: can’t assign io (size 0x4)
pci 0000:00:00.0: PCI bridge to [bus 01]
pci 0000:00:00.0: bridge window [mem 0x28800000-0x288fffff pref]