FW: A help required!!!!!

[Ali Najafi - Azfin <alinajafi@hqexchg.aztech.com.sg>]

> Unfortunately, I do not have experience in the topic that you are asking
> me.
> 
> You mail rose this question on my mind though: What is virtual mapping of
> I/O into memory? Does it mean that you somehow map the I/O into memory
> space through ONLY software means, and that your program accesses that I/O
> by memory instructions?
> 
> I can share this, I don't know if it helps. We designed a PCI device long
> ago that had an I/O BAR and a memory BAR. These two BAR's where accessing
> the very same registers on the chip. That is to say, no matter you access
> the chip through the I/O BAR or the memory BAR, the chip would access the
> very same set of registers. We had provided the memory BAR only for the
> sake of following certain guidelines and never used it and only accessed
> the card through the I/O BAR, by I/O instructions. The person who
> developed the device driver for it also only used the I/O, and was quite
> happy to do so. I don't know if that would be easier for you to only use
> the I/O or whether it is a must for you to perform the mapping.
> 
> I can't say my $0.02, it wasn't even $0.01  !!
> A. Najafi
> 
> I am working on the development of a Win NT device driver for a PCI based
> ATM 25 Mbps card.... 
> I am able to read the I/O base address(physical address) of the card(which
> the PCI controller asdsigns to the card during startup)
> but i am not able to map this I/O space into system memory(ie. get a
> virtual mapping for the physical address)...
> 
> I would be thankful to u if u could help me in this regard.
> 
> Also if i happen to get the I/O virtual mapping, how do i check whether
> the mapped space in system memory is indeed correct.....
>