RE: eMMC support

[Sai Pavan Boddu]

Hi Cedric

> -----Original Message-----
> From: Cédric Le Goater <clg@kaod.org>
> Sent: Wednesday, February 10, 2021 3:27 PM
> To: Sai Pavan Boddu <saipava@xilinx.com>; Edgar Iglesias <edgari@xilinx.com>;
> Joel Stanley <joel@jms.id.au>; Andrew Jeffery <andrew@aj.id.au>
> Cc: qemu-devel@nongnu.org; Philippe Mathieu-Daudé <f4bug@amsat.org>
> Subject: Re: eMMC support
> 
> 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 ?
[Sai Pavan Boddu] Anyway BOOT_PARTITION_ENABLE bits are persistent over power 
cycles, which needs be implemented as properties.
> 
> > And also is it good to calculate the address offset once when
> > partition access bits are set, rather than doing it for every read/write ?
> 
> Yes and no. It would add state to the sd object.
[Sai Pavan Boddu] Yeah. We already have a member in the state "sd->data_start", 
which can be updated based on value in PARTITION_ACCESS. I feel there is no 
harm in updating data_start, correct me if I'm wrong.

Regards,
Sai Pavan
> 
> Thanks,
> 
> C.