On Friday 07 December 2012, Michal Simek wrote: > On 12/06/2012 10:27 PM, Bjorn Helgaas wrote: > > [+cc linux-pci] > > > > On Thu, Dec 6, 2012 at 7:23 AM, Michal Simek <michal.simek@xxxxxxxxxx> wrote: > >> Hi guys, > >> > >> I have a question regarding to sharing generic OF pcie driver between > >> two architectures MB and ARM Zynq. > >> Is drivers/pci/pcie location good for it? > >> Make no sense to have the same driver in two locations. > > > > I think you're talking about a PCI host bridge driver. It would > > definitely be nice to move toward a generic, shared driver. Host > > bridge drivers are responsible for enumerating the PCI hierarchy below > > the bridge. Enumeration is not really PCIe-specific, so I wouldn't > > put it in drivers/pci/pcie. > > Not a PCI expert, just trying to find out the proper location for this shared driver. I'd suggest creating a drivers/pci/host directory. We will have more of these in the future. AFAIK, there is no fully generic (architecture independent) way to interface a PCI host driver to the PCI subsystem, but I think we are getting closer to that. You are probably fairly free to modify the microblaze architecture specific code though if needed. > >> Is using readl/writel IO functions in this driver the best option > >> which we can have? > >> Or is there any other recommendation? > > > > I'm not really a driver person, but if you're writing a new driver, > > wouldn't you use the iomap interfaces (ioremap(), ioread32(), etc) > > rather than readl()? > > That driver exists but it is not in mainline and it is better to directly > add it to proper location with correct io functions. > The question is if ioread/iowrite functions are correct one. > PowerPC io-defs.h suggests that readl/writel should be used for PCI. ioread32/iowrite32 are defined to behave the same way readl/writel regarding addressing modes and barriers, but also allow operating on __iomem pointers that were returned from ioport_map(). You probably don't need that. Some architectures like powerpc have their own accessors for on-chip MMIO areas, but ARM does not. The PowerPC rule is that you must use either readl/writel or ioread32/iowrite32 to access devices connected to a PCI bus, but you would not necessarily do that for the PCI host controller itself on PowerPC. Arnd Arnd -- 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
