Re: [Qemu-devel] [PATCH] integrator/cp: Wire up MMC card detection

[Jan Kiszka]

On 2015-02-03 19:03, Peter Maydell wrote:
> On 30 January 2015 at 20:19, Jan Kiszka <address@hidden> wrote:
>> This allows to use MMC emulation with the Integrator/CP model. Well,
>> mostly. There seems to be timing issues with Linux so that the card is
>> not always detected (but most of the time).
>>
>> Note that the read-only pin is intentionally left unconnected because
>> the PIC model could deliver it incorrectly as interrupt to the guest
>> while the spec says that this pin is just for status reading.
> 
> I'm not sure what you mean here. The WPROT signal isn't wired
> up to the SIC at all as far as I can see -- it's just a read-only
> bit in the CP_INTREG register in what we model as "icp_control".
> 
> Your patch doesn't seem to do anything with the icp_control at all,
> which doesn't look right, because the docs say that to clear the
> 'card insert' interrupt reported by the SIC you need to write
> to the CP_INTREG register.
> 
> The gpio out line from the PL181 is just a status line (high when
> a card is present, low if not); there needs to be a latch somewhere
> in here that gets reset by the CP_INTREG write, the PL181 line
> isn't just wired directly to the SIC.

Indeed, read this too quickly. Let's see if modeling this more correctly
will also improve the detection reliability.

Jan

signature.asc
Description: OpenPGP digital signature