RE: eMMC support

[Sai Pavan Boddu]

Hi Cedric,

> -----Original Message-----
> From: Cédric Le Goater <clg@kaod.org>
> Sent: Tuesday, February 2, 2021 3:37 AM
> 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
> 
> On 2/1/21 11:01 PM, Cédric Le Goater wrote:
> > Hello,
> >
> >>> 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.
> >>
> >> */[Sai Pavan Boddu] I’m revisiting eMMC now, made some patches on top
> >> of previous series sent by “Vincent Palatin”./*
> >>
> >> */Would you like to share your changes, which made aspeed machines to
> >> work ?/*
> >>
> >> */Regards,
> >> 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,
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 ?

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 ?

Regards,
Sai Pavan
> >     42c9d57f5cd0 Joel Stanley - sd: mmc: Subtract bootarea size from blk
> >     218301406607 Joel Stanley - sd: mmc: Support boot area in emmc image
> >     df0452923b56 Cédric Le Goater - sd: mmc: Add Extended CSD register
> definitions
> >     416c02bbfd32 Sai Pavan Boddu - sd: mmc: Add mmc switch function
> support
> >     a228aef1a209 Sai Pavan Boddu - sd: mmc: add CMD21 tuning sequence
> >     9b177d7baf8e Sai Pavan Boddu - sd: mmc: Update CMD1 definition for
> MMC
> >     6677e4eb6812 Vincent Palatin - sd: add eMMC support
> 
> here :
> 
> https://github.com/legoater/qemu/commits/aspeed-6.0
> 
> C.