Re: [PATCH v3 0/2] mmc: host: Disable auto-cmd12 during ffu

[Adrian Hunter <adrian.hunter@intel.com>]

On 25/10/23 14:30, Avri Altman wrote:
> Field Firmware Update (ffu) may use close-ended or open ended sequence.
> Each such sequence is comprised of a write commands enclosed between 2
> switch commands - to and from ffu mode.
> 
> Some platforms generate auto command error interrupt when it shouldn't,
> e.g. auto-cmd12 while in close-ended ffu sequence.  I encountered  this
> issue while testing fwupd (github.com/fwupd/fwupd) on HP Chromebook x2,
> a qualcomm based QC-7c, code name - strongbad. Instead of a quirk, make
> sure it disable auto-cmd12 while close-ended ffu is in progress.

I think I misunderstood this because I was thinking that auto-cmd12
was being used with an open-ended sequence, and that it wasn't
working with FFU.  However it seems mmc-utils is using a closed-ended
sequence.

It looks like the the host controller driver doesn't know that,
because the ioctl interface does not use mrq.sbc and the
SET_BLOCK_COUNT command is sent separately.  Then when the MULTI_WRITE
command is issued, the host controller driver treats it as open-ended
and will enable auto-cmd12 if the controller supports it.

If that is the case, it would be better to fix the ioctl handling
and make it use mrq.sbc instead of issuing SET_BLOCK_COUNT separately.

> 
> v2 -> v3:
>  - fix an issue Reported-by: kernel test robot <lkp@intel.com>
> 
> v1->v2:
>  - Attend Adrian's suggestions
> 
> Avri Altman (2):
>   mmc: core: Mark close-ended ffu in progress
>   mmc: host: msm: Disable auto-cmd12 during ffu
> 
>  drivers/mmc/core/block.c     | 34 ++++++++++++++++++++++++++++++++++
>  drivers/mmc/host/sdhci-msm.c | 24 ++++++++++++++++++++++++
>  include/linux/mmc/host.h     |  1 +
>  include/linux/mmc/mmc.h      |  1 +
>  4 files changed, 60 insertions(+)
>