[PATCH V7 02/17] SPEAr13xx: Add PCIe host controller base driver support.

pratyush pratyush.anand at st.com
Wed Apr 13 08:11:14 EDT 2011

Hello Arnd,

>> Sorry, may be I could not get this point correctly. Do you mean that,
>> I should create a static mapping for IN0_MEM_SIZE (200 MB) and 
>> IN_IO_SIZE (20 MB) during board initialization itself?
> Only IN_IO_SIZE. The I/O space is implicitly assumed to be mapped, while
> the memory space is mapped by device drivers individually.

Ok.. will do it..

>>> Please reread my previous comments. You have to redefine __io() in order to make
>>> the I/O port accesses work. When you do that, you cannot define
>>> __io_address (which is used by non-PCI code) as using __io.
>> __io_address is not used by PICe routines. Also, this is not part of 
>> this patch. 
> Yes, that was my point.


>>> Is IN_IO_SIZE per host, or this shared across all hosts?
>> This is per host. So is it not a practical size?
>> What should be a reasonable IO size?
> 64 KB is more than enough per host. That is the maximum that an x86 PC
> can address, so devices usually use very little of this, if anything.
> There are some advantages to using 64KB combined for all hosts, but
> the easiest way should probably be to reserve 1 MB for the space
> and use 64 KB for each of them.
> If you have a PCI-ISA bridge chip or a card that has one, it needs to
> be on a host that has its I/O space in the first 64 KB.

I will modify, as you have suggested!!!


More information about the linux-arm-kernel mailing list