On Oct 21, 2008, at 9:46 AM, Wolfgang Denk wrote:
> Dear Kumar Gala,
>
> In message <1224598531-2698-1-git-send-email-
> [EMAIL PROTECTED]> you wrote:
>> PCI bus is inherently 64-bit. We should treat all PCI related bus
>> addresses as 64-bit quanities. This allows us to have the ability
>> to support devices or memory on the PCI bus above the 32-bit
>> boundary.
>
> I don't think this is a good idea. There are pure 32 bit systems out
> there which will never use more than 32 bit for the PCI resources, so
> why load them with the additional memory size and execution time?
>
> Should we not enable this only for such systems that actually need it?
We could, however it seems the impact is pretty small on those systems
with pure 32-bit PCI. I think the different in testing etc may not be
worth it:
text data bss dec hex filename
350588 44964 41909 437461 6acd5 u-boot (32-bit pci structs)
351100 44964 42349 438413 6b08d u-boot (64-bit pci structs)
----------------------------------------------
512 0 440 952 3b8
If this is desired to be configurable should I introduce a pci_addr_t/
pci_size_t? Coupling to phys_addr_t/phys_size_t doesn't make sense to
me because its perfectly reasonable to have a 64-bit PCI device work
in a 32-bit system.
- k
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