Unified PCI API

Chris Caudle chris at chriscaudle.org
Sun Feb 20 02:03:44 UTC 2005


On Saturday 19 February 2005 06:49 pm, Joel Sherrill <joel at OARcorp.com> wrote:
> For those who care, the x86 PCI API uses a "signature u32" to identify
> devices while the PowerPC/cpukit API uses a "bus, device" combination to
> identify devices.

Assuming the u32 is because of Intel PCI BIOS convention, it is actually a 
multi-field number that is the concatenation of bus, device, function.
My opinion is that bus, device, function is more clear because it maps 
directly to how the bus access is defined.
It sounds like the PowerPC API made an expediency in only using bus, device 
but for completeness the API should use bus, device, function so that 
multi-function devices can be handled correctly.

-- 
Chris



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