[SeaBIOS] non-emulated AHCI hardware

Jonathan A. Kollasch jakllsch at kollasch.net
Thu Feb 17 15:28:54 CET 2011


On Sat, Feb 12, 2011 at 11:43:24PM +0000, Jonathan A. Kollasch wrote:
> Hi,
> 
> I've been trying SeaBIOS's AHCI driver on AMD SB710 hardware under
> coreboot.  Both AMD's AHCI BIOS and NetBSD's ahcisata(4) drivers are
> happy enough with the hardware's state after coreboot/SeaBIOS.
> 
> However, SeaBIOS's AHCI driver just falls into a dead loop waiting for
> commands to complete. This is due to at least two problems.
> 
> The immediate problem is that we tell the HBA that a Host To Device FIS
> is 4 dwords. The correct value is 5 dwords if I read the specs right.
> 
> But, when the H2D FIS length we give to the HBA is 5, I have a more
> perplexing problem.  The machine hardlocks when HBA registers are
> read after the command has been issued.  When I examine the Command List
> and Receive FIS Area, etc. before and after issuing the command, they have
> not changed.

Actually it wasn't a hardlock, it was a dead loop. :-)

I have it (mostly) working now, just have to get it polished up a bit.

	Jonathan Kollasch



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