[U-Boot] [PATCH] ARM: mx6: Enable MMC FS boot support

[Robert Nelson]

On Wed, Apr 27, 2016 at 6:41 PM, Marek Vasut <marex at denx.de> wrote:

> On 04/28/2016 01:32 AM, Robert Nelson wrote:
> >
> >
> > On Wed, Apr 27, 2016 at 6:28 PM, Marek Vasut <marex at denx.de
> > <mailto:marex at denx.de>> wrote:
> >
> >     On 04/28/2016 01:16 AM, Tom Rini wrote:
> >     > On Thu, Apr 28, 2016 at 01:06:07AM +0200, Marek Vasut wrote:
> >     >
> >     >> Enable support for booting U-Boot image from filesystem instead
> of some
> >     >> random offset on the SD card. This makes the board usable by
> putting the
> >     >> u-boot.img to first partition of the SD card and writing the SPL
> this way:
> >     >> $ dd if=u-boot-with-spl.imx of=/dev/sdX seek=2 bs=512
> >     >
> >     > Wait, you're still writing u-boot + SPL to the device and not just
> SPL,
> >     > but it's still preferring the filesystem one over the appended one?
> >     >
> >
> >     Ha, good point. I should've written the 'SPL' file instead, which is
> >     just the SPL without U-Boot. I don't want to install U-Boot to random
> >     offset on the SD card as it has the potential to corrupt data if the
> >     u-boot binary changes in size.
> >
> >     If I install u-boot image to random offset 138 blocks from the start
> of
> >     SD card, it will boot that, otherwise it will load from FS.
> >
> >     I will update the commit message with the correct info, sorry.
> >
> >
> > Oh, we went thru this last year...
> >
> > http://lists.denx.de/pipermail/u-boot/2015-August/222061.html
> >
> > If your serious about changing "one" i.mx6 board, you need to change
> > them "all".
>
> No, I do not have to change and will not change any other boards I
> cannot test.
>

Okay, so if you can't test, are you going to keep an updated database:

boardx = boots this way?
boardy = boots that way?

Otherwise, keep like the other i.mx6's..

Or throw it under a "kconfig" so you can easily enable either mode.


>
> > Otherwise leave a 1MB hole on your mmc partition and dd spl/u-boot.img
> > as that works for ti/imx/sunxi...
>
> No, this design is utterly broken. If U-Boot grows beyond 1 MiB, it will
> corrupt my data, silently. I will not have this. I would much rather see
> these broken designs go away and have everyone move to
> SPL in random location as mandated by BootROM (unfortunately) and
> u-boot.img on a filesystem. That way, u-boot.img can grow and shrink
> either way, without endangering any surrounding data.
>
> Can you give me any argument why writing u-boot.img to random location
> on the SD card is better than storing it on a filesystem ?
>

1:

Yeap, end users like to delete "MLO/u-boot.img" that was in the "fat" boot
partition in our production beaglebone images specifically "2014-05-14"
 which was shipped by default on rev C.  Thus soft-bricking/etc boards..

http://beagleboard.org/latest-images

Moving it under the 1MB location, has solved that problem.

2:

fedora/debian/ubuntu/yocto all expect this board to have these settings..

Regards,

-- 
Robert Nelson
https://rcn-ee.com/