Re: [Qemu-devel] [PATCH] ahci: add port I/O index-data pair

[Daniel Verkamp]

On Sun, Aug 28, 2011 at 11:48 AM, Alexander Graf <address@hidden> wrote:
>
> On 27.08.2011, at 04:12, Daniel Verkamp wrote:
>
>> Implement an I/O space index-data register pair as defined by the AHCI
>> spec, including the corresponding SATA PCI capability and BAR.
>>
>> This allows real-mode code to access the AHCI registers; real-mode
>> code cannot address the memory-mapped register space because it is
>> beyond the first megabyte.
>
> Very nice patch! I'll check and compare with a real ICH-9 when I get
> back to .de, but I'd assume you also did that already ;). Once I checked
> that the IO region is set up similarly, I'll give you my ack.

Please do double check against real hardware if you get the chance - I
don't have a real ICH-9 handy to test against.  This is all written
based on my reading of the spec and testing with an internal DOS
developer tool from work.

I am mainly curious how the real thing handles writes to the index
register that aren't divisible by 4 or are beyond the end of the
register set (and how big that really is on ICH-9).  Judging by the
bits marked "RO" in the spec, I would guess writing 0x13 to the index
and then reading it back should give 0x10, but I haven't tested it on
real hw.

Thanks,
-- Daniel