[SeaBIOS] [PATCH] sdcard: abort controller setup if capabilities invalid

[Kevin O'Connor]

On Wed, Mar 16, 2016 at 08:53:09PM -0500, Matt DeVillier wrote:
> If the version and low/high capabilities flags of a sdcard controller are
> invalid (0xFFFF), assume the controller address is invalid, and exit setup
> before attempting to reset the controller, which would introduce an
> unnecessary
> delay, since the reset would ultimately fail after timing out.
> 
> This eliminates the delay in displaying the boot menu message on Baytrail
> ChromeOS devices, where multiple /etc/sdcard entries are present in a single
> payload to cover the range of eMMC controller addresses used.
> 
> Signed-off-by: Matt DeVillier <matt.devillier at gmail.com>

I think this is a good idea, but I don't think we can rely on the
memory having all 0xff.  At a minimum I think 0x00 should be checked
for as well, but ideally the controller would have a signature we
could check.

BTW, the patch got white-space mangled.

-Kevin