Re: eMMC support

[Cédric Le Goater]

On 2/10/21 2:05 PM, Joel Stanley wrote:
> On Wed, 10 Feb 2021 at 09:56, Cédric Le Goater <clg@kaod.org> wrote:
>>
>> Hello Sai Pavan,
>>
>> [ ... ]
>>
>>>>> The patchset is in the aspeed-6.0 branch :
>>>>>
>>>>>     df91d012672c Cédric Le Goater - hw/arm/aspeed: Load eMMC first boot
>>>>>                                     area as a boot rom
>>>>>     27b75a7ad322 Cédric Le Goater - hw/arm/aspeed: Add eMMC property
>>>>>     2836cf5a15a1 Joel Stanley - hw/arm/aspeed: Set boot device to emmc
>>>
>>> [Sai Pavan Boddu] I see you guys have implemented the boot area access here,
>>
>> The boot partition modeling fits our needs to boot the Aspeed machine
>> but this is very custom.
>>
>>> I was assuming, your use-case just need to access data from boot partitions.
>>> We are not implementing eMMC boot operations or Alternative bootmode right ?
>>
>> Joel could say more about it ?
> 
> The solution I came up with has room for improvement. There's no way
> to tell the qemu sd device what boot partitions it should expect to
> find, and likewise there's no way for the emulated machine to check
> that the image is formatted in the way it expects.
> 
> If there was a way to add metadata to the image (through qcow2?) then
> we could use this to define the boot partition sizes in the image, and
> have the model use these numbers to populate CSD_EXT. It's only an
> idea, and I don't know if qcow2 supports this kind of metadata.

We could add a new QEMU MMC block device with a set of properties
to describe the layout maybe ? 

C.