On Tue, Nov 18, 2014 at 11:30:11AM +0000, Arnd Bergmann wrote: > On Tuesday 18 November 2014 19:17:32 Yijing Wang wrote: > > On 2014/11/17 22:13, Arnd Bergmann wrote: > > > On Monday 17 November 2014 18:21:34 Yijing Wang wrote: > > >> This series is based Linux 3.18-rc1 and Lorenzo Pieralisi's > > >> arm PCI domain cleanup patches, link: > > >> https://patchwork.ozlabs.org/patch/407585/ > > >> > > >> Current pci scan interfaces like pci_scan_root_bus() and directly > > >> call pci_create_root_bus()/pci_scan_child_bus() lack flexiblity. > > >> Some platform infos like PCI domain and msi_chip have to be > > >> associated to PCI bus by some arch specific function. > > >> We want to make a generic pci_host_bridge, and make it hold > > >> the platform infos or hook. Then we could eliminate the lots > > >> of arch pci_domain_nr, also we could associate some platform > > >> ops something like pci_get_msi_chip(struct pci_dev *dev) > > >> with pci_host_bridge to avoid introduce arch weak functions. > > >> > > >> This RFC version not for all platforms, just applied the new > > >> scan interface in x86/arm/powerpc/ia64, I will refresh other > > >> platforms after the core pci scan interfaces are ok. > > > > > > I think overall this is a good direction to take, in particular > > > moving more things into struct pci_host_bridge so we can > > > slim down the architecture specific code. > > > > Hi Arnd, thanks very much for your review and comments! > > > > > > > > I don't particularly like the way you use the 'pci_host_info' > > > to pass callback pointers and some of the generic information. > > > This duplicates some of the issues we are currently trying > > > to untangle in the arm32 code to make drivers easier to share > > > between architectures. > > > > What arm32 code you are trying to untangle for example ? > > We have a few problems that currently prevent us from using shared > drivers across arm32 and arm64: > > - arm32 has an architecture-defined pci_sys_data structure, but > we really want to have one that is defined by the host bridge driver > and that is architecture independent. Some core functions depend > on this structure at the moment, which Lorenzo is trying to > undo Yes, and on this specific point I would like to understand why we are adding yet more pci_sys_data data in the last series that is already in -next: https://lkml.org/lkml/2014/10/27/85 What does this buy us ? The cover letter says already that there *is* a better solution, why do not we work on that instead of adding more churn to arch specific code ? Thanks, Lorenzo -- 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
