Re: [Qemu-devel] Re: RFC: emulation of system flash

[Michal Suchanek]

Hello,

On 11 March 2011 20:09, Jordan Justen <address@hidden> wrote:
> On Thu, Mar 10, 2011 at 16:27, Carl-Daniel Hailfinger
> <address@hidden> wrote:
>> Auf 11.03.2011 01:19, Jan Kiszka schrieb:
>>> At least it's an in-band interface, which is the better choice as we
>>> currently only have a PIIX3 southbridge for x86, predating even FWHs.
>>>
>>
>> Right, that pretty much kills the option of using SPI unless someone
>> wants to emulate a flash translation controller (e.g. the ITE IT8716F
>> Super I/O). Can be done, would work, but the IT8716F has some quirks
>> (max 1 MB SPI flash chips) which make it a less desirable option for
>> emulation.
>
> I don't much like this, but we might consider adding the SPI host
> controller MMIO just below the flash data.  For the firmware, we
> usually will know the size of firmware device that we've built for.
> It seems SPI flash is pretty common today, and it sounds like
> Carl-Daniel may have some SPI emulation code.
>
> Am I understanding correctly that CFI is programmed via MMIO in the
> flash memory space?  How difficult would it be to emulate CFI?  Does
> CFI have the same power-of-2 size flexibility as SPI?
>

Maybe it would be more useful to implement Intel LPC controller and
attach the flash to that (I assume it is the place where it would be
attached). The LPC controller is useful on its own (eg OS X assumes it
exists).

I am not sure how difficult hardware it is, though.

Thanks

Michal