Hi Arnd, On 3/9/2015 5:35 AM, Arnd Bergmann wrote: > On Friday 06 March 2015 10:00:34 Ray Jui wrote: >>> >> >> Although I have not tested it, but to my best knowledge there shouldn't >> be any technical issue by making the PCIe iProc driver a loadable module >> and installing the module later after the kernel finishes booting. >> >> But I wonder why I haven't seen any PCIe host driver being allowed to be >> compiled as module? Maybe there's no obvious benefit of doing that. >> People typically opt to load slave devices as module but tend to keep >> the bus or host devices compiled in. >> >> And to allow a PCI host driver to be compiled as module, some PCI >> functions need to have their symbols exported: >> >> ERROR: "pci_common_swizzle" [drivers/pci/host/pcie-iproc.ko] undefined! >> ERROR: "pci_fixup_irqs" [drivers/pci/host/pcie-iproc.ko] undefined! >> ERROR: "pci_assign_unassigned_bus_resources" >> [drivers/pci/host/pcie-iproc.ko] undefined! >> ERROR: "pci_remove_root_bus" [drivers/pci/host/pcie-iproc.ko] undefined! >> ERROR: "pci_stop_root_bus" [drivers/pci/host/pcie-iproc.ko] undefined! >> ERROR: "pci_create_root_bus" [drivers/pci/host/pcie-iproc.ko] undefined! >> >> Maybe Bjorn can help to shed some light here? Should I go ahead and >> export_symbol these PCI functions and make the iProc PCI driver "tristate"? > > My best guess is that no loadable driver ever tried to use these and > we should indeed just export them. True. I can export those symbols. > > The call to pci_assign_unassigned_bus_resources could be avoided by using > pci_rescan_bus(), which would simplify the driver a little, but for > some reason, nothing else uses that, so I'm not sure about it. > > The pci_remove_root_bus/pci_stop_root_bus calls are rarely used anywhere > else. Are they functional to the point where you could unload a pci > host driver that is a loadable module? If so, that would be > wonderful. It is quite wonderful, :) I added driver remove function support and tested it out. I'm able to install/remove/install the iProc PCIe platform driver as a kernel loadable module. pci_remove_root_bus/pci_stop_root_bus works fine. See logs below. -bash-3.2# insmod pcie-iproc-pltfm.ko [ 54.058546] PCI host bridge /pcie@18012000 ranges: [ 54.064584] IO 0x28000000..0x2800ffff -> 0x00000000 [ 54.071003] MEM 0x20000000..0x23ffffff -> 0x20000000 [ 54.330194] iproc-pcie 18012000.pcie: PCI host bridge to bus 0000:00 [ 54.338138] pci_bus 0000:00: root bus resource [bus 00-ff] [ 54.344983] pci_bus 0000:00: root bus resource [io 0x0000-0xffff] [ 54.352683] pci_bus 0000:00: root bus resource [mem 0x20000000-0x23ffffff] [ 54.361254] iproc-pcie 18012000.pcie: link: UP [ 54.367086] PCI: bus0: Fast back to back transfers disabled [ 54.374046] pci 0000:00:00.0: bridge configuration invalid ([bus 00-00]), reconfiguring [ 54.400237] PCI: bus1: Fast back to back transfers disabled [ 54.407274] pci 0000:00:00.0: BAR 8: assigned [mem 0x20000000-0x200fffff] [ 54.415766] pci 0000:01:00.0: BAR 1: assigned [mem 0x20000000-0x2007ffff] [ 54.424241] pci 0000:01:00.0: BAR 6: assigned [mem 0x20080000-0x200bffff pref] [ 54.433245] pci 0000:01:00.0: BAR 0: assigned [mem 0x200c0000-0x200dffff] [ 54.441710] pci 0000:01:00.0: BAR 3: assigned [mem 0x200e0000-0x200e3fff] [ 54.450173] pci 0000:01:00.0: BAR 2: no space for [io size 0x0020] [ 54.457979] pci 0000:01:00.0: BAR 2: failed to assign [io size 0x0020] [ 54.466217] pci 0000:00:00.0: PCI bridge to [bus 01] [ 54.472404] pci 0000:00:00.0: bridge window [mem 0x20000000-0x200fffff] [ 54.480945] pcieport 0000:00:00.0: enabling device (0140 -> 0142) [ 54.488767] e1000e 0000:01:00.0: enabling device (0140 -> 0142) [ 54.496315] e1000e 0000:01:00.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode [ 54.507958] e1000e 0000:01:00.0 0000:01:00.0 (uninitialized): Failed to initialize MSI-X interrupts. Falling back to MSI interru. [ 54.522913] e1000e 0000:01:00.0 0000:01:00.0 (uninitialized): Failed to initialize MSI interrupts. Falling back to legacy interr. [ 54.643486] e1000e 0000:01:00.0 eth0: registered PHC clock [ 54.650379] e1000e 0000:01:00.0 eth0: (PCI Express:2.5GT/s:Width x1) 68:05:ca:28:19:e8 [ 54.660254] e1000e 0000:01:00.0 eth0: Intel(R) PRO/1000 Network Connection [ 54.668834] e1000e 0000:01:00.0 eth0: MAC: 3, PHY: 8, PBA No: E46981-008 -bash-3.2# rmmod pcie-iproc-pltfm [ 66.465834] e1000e 0000:01:00.0 eth0: removed PHC -bash-3.2# insmod pcie-iproc-pltfm.ko [ 71.043195] PCI host bridge /pcie@18012000 ranges: [ 71.049235] IO 0x28000000..0x2800ffff -> 0x00000000 [ 71.055652] MEM 0x20000000..0x23ffffff -> 0x20000000 [ 71.315192] iproc-pcie 18012000.pcie: PCI host bridge to bus 0000:00 [ 71.323135] pci_bus 0000:00: root bus resource [bus 00-ff] [ 71.329979] pci_bus 0000:00: root bus resource [io 0x0000-0xffff] [ 71.337679] pci_bus 0000:00: root bus resource [mem 0x20000000-0x23ffffff] [ 71.346249] iproc-pcie 18012000.pcie: link: UP [ 71.352072] PCI: bus0: Fast back to back transfers disabled [ 71.375261] PCI: bus1: Fast back to back transfers disabled [ 71.382291] pci 0000:00:00.0: BAR 8: assigned [mem 0x20000000-0x200fffff] [ 71.390782] pci 0000:01:00.0: BAR 1: assigned [mem 0x20000000-0x2007ffff] [ 71.399258] pci 0000:01:00.0: BAR 6: assigned [mem 0x20080000-0x200bffff pref] [ 71.408263] pci 0000:01:00.0: BAR 0: assigned [mem 0x200c0000-0x200dffff] [ 71.416728] pci 0000:01:00.0: BAR 3: assigned [mem 0x200e0000-0x200e3fff] [ 71.425190] pci 0000:01:00.0: BAR 2: no space for [io size 0x0020] [ 71.432996] pci 0000:01:00.0: BAR 2: failed to assign [io size 0x0020] [ 71.441235] pci 0000:00:00.0: PCI bridge to [bus 01] [ 71.447422] pci 0000:00:00.0: bridge window [mem 0x20000000-0x200fffff] [ 71.456125] pcieport 0000:00:00.0: Signaling PME through PCIe PME interrupt [ 71.464812] pci 0000:01:00.0: Signaling PME through PCIe PME interrupt [ 71.473411] e1000e 0000:01:00.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode [ 71.485069] e1000e 0000:01:00.0 0000:01:00.0 (uninitialized): Failed to initialize MSI-X interrupts. Falling back to MSI interru. [ 71.500025] e1000e 0000:01:00.0 0000:01:00.0 (uninitialized): Failed to initialize MSI interrupts. Falling back to legacy interr. [ 71.624549] e1000e 0000:01:00.0 eth0: registered PHC clock [ 71.631444] e1000e 0000:01:00.0 eth0: (PCI Express:2.5GT/s:Width x1) 68:05:ca:28:19:e8 [ 71.641314] e1000e 0000:01:00.0 eth0: Intel(R) PRO/1000 Network Connection [ 71.649894] e1000e 0000:01:00.0 eth0: MAC: 3, PHY: 8, PBA No: E46981-008 > > Arnd > I'll submit patch series v4 with loadable module support. Thanks, Ray -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
