[SeaBIOS] Does SeaBIOS support eMMC?

[Kevin O'Connor]

On Tue, Jan 12, 2016 at 12:26:11PM -0500, Kevin O'Connor wrote:
> On Tue, Jan 12, 2016 at 05:07:08PM +0000, Scheithauer, Mario wrote:
> > > The drive is showing up as an 2TB drive, so something is clearly wrong with the
> > > size detection.  Upon attempting to boot from the drive, a read CRC error occurs.
> > > I wonder if the drive is not in sync with the controller on the number of data lines in
> > > use.
> >  
> > I believe the mechanism to determine the size for eMMC4.5 devices are differently than up to now.
> > However, that is no problem.
> 
> Yes - on v4.0 and later MMC devices SeaBIOS reads from the size from
> the EXT_CSD register.  The log indicates that SEND_EXT_CSD was sent,
> so SeaBIOS is recognizing the hardware version, and the command
> completes without error.  But the size results do look suspect.

Ah, just noticed that the size reported (2097151) is 0x1fffff.  Which
means the SEC_COUNT field in EXT_CSD was almost certainly 0xffffffff
before SeaBIOS adjusted for MiB and 512byte sectors.

That could be a further indication of bus data width mismatch between
card and host.  The patch I previously sent could help diagnose if
that is the case.

-Kevin