On Sat, Apr 16, 2016 at 1:01 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > On Saturday 16 April 2016 12:50:13 Jayachandran C wrote: >> > >> > I still think it would be better to keep the loadable PCI host drivers >> > separate from the ACPI PCI infrastructure. There are a number of >> > simplifications that we want to do to the DT based drivers in the long >> > run, so it's better if that code is not shared at this level. Abstracting >> > out the ECAM code is fine, but at that point you should be able to just >> > call it from the ACPI layer. >> >> The issue is not with this patch (in my opinion). This patch is just >> re-arranging how thunder specific data is maintained. Earlier it was >> a container_of gen_pci, now it is ->priv of pci_config_window. >> >> I can see the issue in patches 12 and 13 of this patchset which adds >> ACPI fixups into the thunder OF driver. > > Right, I commented on this one, because it seems to rearrange the code > in order to do the later one. Patches 11- 13 are not from me, and I am not completely on board on the approach of adding the sections.We can look at reworking this. >> The simple approach when doing modular PCI drivers would be to make >> pci-thunder-*.c like pci-host-common.c, to be compiled in if configured. >> The fie will contain all the Thunder quirks and can export >> pci_thunder_ecam_ops. > > I would argue that we should not export anything from drivers/pci/host, > those should really be standalone drivers that do not interact with other > subsystems. pci-host-common.c goes against being standalone. The files calling pci_host_common_probe() are expected to have custom ECAM ops the way it is written now. We need to have a reasonable way to share those ECAM ops if needed by ACPI. > How much code would you need to duplicate from thunder-ecam to have > the same functionality available in ACPI? My expectation is that it's > not really that much more compared to the code you need for sharing > a single implementation, but you get a lower complexity here, which > makes it easier to understand and to rework. Like I wrote above, the sharing is really simple because both generic ACPI and pci-host-common.c have been written for "ECAM with quirks". The whole pci-thunder-*.c is to support thunder PCI quirks since the generic OF is handled by pci-host-common.c and generic ECAM is now separated - duplicating the whole file for ACPI will be bad. Any suggestions on how to do this better would be really welcome. Thanks, JC. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
