Re: eMMC support

[Cédric Le Goater]

On 9/17/20 8:25 AM, Cédric Le Goater wrote:
> On 9/17/20 2:55 AM, Joel Stanley wrote:
>> On Wed, 16 Sep 2020 at 18:35, Sai Pavan Boddu <saipava@xilinx.com> wrote:
>>>
>>> Hi Philippe,
>>>
>>>
>>>
>>> We are looking to add eMMC support, I searched the mailing list and found a 
>>> series posted on eMMC by “Vincent Palatin”
>>>
>>> https://lists.gnu.org/archive/html/qemu-devel/2011-07/msg02833.html
>>
>> I would be interested in emmc support for the aspeed machines. Please
>> cc me when you post patches.
>>
>>> I would like to consider the above work and mix-up with more changes to 
>>> start adding support for eMMC. Do you have any suggestions on the approach 
>>> followed in above patches ?
>>
>> The patches had minor review comments, but I assume the reason they
>> didn't go anywhere is the author never followed up with further
>> revisions. I would suggest applying them to the current tree, cleaning
>> up any style changes that have happened since they were posted, and
>> re-posting them for review.
> 
> It seems we only care about these three patches :
> 
>   https://patchwork.ozlabs.org/patch/106762
>   https://patchwork.ozlabs.org/patch/106761
>   https://patchwork.ozlabs.org/patch/106763
> 
> It should not be too complex to get something going.
>>> Note: Here is the existing support available in Xilinx fork, which might 
>>> require some work
>>> https://github.com/Xilinx/qemu/blob/master/hw/sd/sd.c
> 
> What are the relevant patches ? 

FYI, aspeed machines successfully boot on top of 16G emmc disk images.
I merged some of xilinx patches on top of the aspeed-6.0 branch to 
improve the model completeness but only the one fixing powerup was 
really necessary. 

The initial diffstat is rather small.

 hw/sd/sd.c             |  168 ++++++++++++++++++++++++++++++++++++++++++-------

We can surely find a way to merge support in mainline without 
covering the whole specs. The Extended CSD register would be the 
big part.

See :

   https://github.com/legoater/qemu/commits/aspeed-6.0

Cheers,

C.