pci_dev start/stop addresses

Morrison, Tom tmorrison at empirix.com
Tue Mar 6 03:37:13 EST 2007

I am trying to port/debug a driver on a 32bit MPC8548E platform 
that is reading the resource start address in the PCI Device 
structure (struct pci_dev). I should mention this driver was
original developed on an X86 platform and works flawlessly...

But, when this driver reads the start value in this struct 
into a local unsigned long value - it comes up as '0x0' (and 
prints out the same via %lx).

Looking closer, it seems that this value is a size - resource_size_t 
- that resolves into a u32 value (and I have printed the physical 
size sizeof(resource_size_t)) and it seems to be the correct size(4).

I am also looking into the sysfs and it appears that for 
this device on the pci bus - it is being 'stored' in this 
resource file as a 64bit value?

I am confused as to what is actually in this PCI device 
structure and/or what is actually returned. I do know that
the even though the start address is coming back as '0', 
the length being calculated is correct (end-start=length)?

It seems to be me, I have some type of mismatch in the 
device tree types and/or an endian problem.

Any insight would be appreciated here!

Tom Morrison
Principal Software Engineer

20 Crosby Drive - Bedford, MA  01730
p: 781.266.3567 f: 781.266.3670 
email: tmorrison at empirix.com 

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