Musings on PCI busses

[Stephen Neuendorffer]

> 1) Probe the host controller in an of_platform driver.  This has the
> advantage of simplicity.  The probe routine will get automatically
> called when the PCI host controller device tree node is registered
> with the of_platform bus.  The bus parenthood also gets reflected in
> the device model and sysfs.  The disadvantage is that it defers PCI
> bus probing until after the of_platform bus is probed (maybe this is
> okay; maybe this already happens anyway).
> 
> 2) Probe the host controller in an subsys_initcall().  Advantage is
> PCI can be probed earlier in the init path.  Disadvantages (minor) are
> that it will always get called if the driver is enabled, and it needs
> to manually search the device tree for PCI nodes.
> 
> I'm leaning towards making it an of_platform driver.  Doing so also
> makes it available to other powerpc processors (not just virtex) in
> the case where a Xilinx FPGA is welded up to a discrete SoC and a host
> controller instance is put into the FPGA.  (one of those weird things
> people do when they have an FPGA in their system).

I agree that something is called for...  The first might be slightly
simpler, since it would probably transparently deal with the presence
of more than one PLB->PCI bridge?

Steve


This email and any attachments are intended for the sole use of the named recipient(s) and contain(s) confidential information that may be proprietary, privileged or copyrighted under applicable law. If you are not the intended recipient, do not read, copy, or forward this email message or any attachments. Delete this email message and any attachments immediately.