Re: proper way to assign fixed PCI resources to a "hotplug" device

[Kumar Gala <galak@kernel.crashing.org>]

On Mar 3, 2006, at 4:07 PM, Greg KH wrote:

> On Fri, Mar 03, 2006 at 11:42:03AM -0600, Kumar Gala wrote:
> > I was wondering what the proper way to assign and setup a single PCI
> > device that comes into existence after the system has booted.  I have
> > an FPGA that we load from user space at which time it shows up on the
> > PCI bus.
>
> Idealy your BIOS would set up this information :)
>
> > It has a single BAR and I need to assign it at a fixed address in PCI
> > MMIO space.
> >
> > All of the exported interfaces I see have to do with having the
> > kernel assign the BAR automatically for me.
> >
> > the following looks like what I want to do:
> >
> > bus = pci_find_bus(0, 3);
> > dev = pci_scan_single_device(bus, devfn);
> > pci_bus_alloc_resource(...);
> > pci_update_resource(dev, dev->resource[0], 0);
> > pci_bus_add_devices(bus);
> >
> > However, pci_update_resource() is not an exported symbol, so I could
> > replace that code with the need updates to the actual BAR.
> >
> > Is this the "right" way to go about this or is there a better
> > mechanism to do this.
>
> Take a look at how the compat pci hotplug driver does this, you  
> probably
> just need to do the same as it.

I found cpqhp_configure_device(), but I dont see anything about how  
to handle assigned a fixed address to the BAR.

I see I could use pci_find_slot()/pci_scan_slot().  Not sure I see  
how that is much better than pci_find_bus()/pci_scan_single_device().

- kumar
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