[parisc-linux] Re: How to determine whether a device is PCI or not

[Matthew Wilcox <matthew@wil.cx>]

On Fri, Oct 29, 2004 at 07:37:18PM -0700, Greg KH wrote:
> Ick, no.  Devices do not "show" their type, you have to explicitly know
> what type they are in order to use them.
> 
> Why are you wanting to know this?  What are you trying to do with a
> generic struct device * where you don't know exactly what type it is?

In order to communicate with PA-RISC firmware, you have to know the path
to a device.  It's typically represented as something like [10/8/4/5/0].
This device can be PCI, GSC or EISA.  There's some moderately arcane
rules for turning a device into a path that you really don't care about,
but we need the devfn for PCI devices and the hw_path for GSC devices.

So what we want to do is, given a struct device, determine its path;
and given a path, turn it into a struct device.  The device model lets
us do this quite nicely -- much better than having duplicated routines
for starting with a pci_dev or a parisc_device.

If you prefer to keep this out of linux/pci.h, that's fine, we can keep
it private to arch/parisc.  I thought this might be something other
architectures might want to use (maybe for openfirmware?)

-- 
"Next the statesmen will invent cheap lies, putting the blame upon 
the nation that is attacked, and every man will be glad of those
conscience-soothing falsities, and will diligently study them, and refuse
to examine any refutations of them; and thus he will by and by convince 
himself that the war is just, and will thank God for the better sleep 
he enjoys after this process of grotesque self-deception." -- Mark Twain
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