[meta-freescale] [meta-fsl-arm-extra] Booting RIoTboard

[Nikolay Dimitrov]

Hi Gary,

On 04/23/2015 12:37 AM, Gary Thomas wrote:
> I've just built an image for the i.MX6DL/RIoTboard using the latest
> master (fido).  I had to add this line to local.conf:
> MACHINE_EXTRA_RRECOMMENDS_remove_imx6dl-riotboard =
> "fsl-alsa-plugins" as the fsl-alsa-plugins won't currently build with
> Linux-4.0
>
> Now I'm trying to boot the image.  I've copied it to my SD card and
> set the switches appropriately (I found two web pages about this and
> they have conflicting information!  The answer seems to be
> SW1-SW8=On/Off/On/Off/Off/On/Off/On)

I have 2 riotboards both booting from sdcards, here are their
configurations:
- slot J6 (USDHC2), SW1-8 = On/Off/On/Off/Off/On/On/Off
- slot J7 (USDHC3), SW1-8 = On/Off/On/Off/Off/On/Off/On

> I get the U-Boot prompt from the image I built (it has today's date),
> but the SD card doesn't boot from there.  The default boot commands
> seem to be looking for boot scripts, etc, but there are none on the
> SD card, only a zImage and DTB file.
>
> Is there some documentation, perhaps in meta-fsl-arm-extra, that
> helps (and I've missed)??
>
> Any help on how to boot this board would be appreciated.

Fido uses U-Boot v2015.04. Assuming that you haven't modifed the
upstream version, v2015.04 uses extlinux boot mechanism, which requires
the following files to be available on your boot partition:

/boot/extlinux/extlinux.conf
/boot/imx6dl-riotboard.dtb
/boot/uImage

Extlinux.conf should have the following content:

default yocto
label yocto
kernel /boot/uImage
devicetree /boot/imx6dl-riotboard.dtb
append console=ttymxc1,115200 root=/dev/mmcblk0p1 rw

Technically speaking, recent versions of U-Boot for riotboard are quite
plug-and-play - as long as you have properly placed your extlinux
files, the bootloader will automatically find them on any attached
storage and boot as piece of cake (works also with rootfs on usb-disk).

If you have partitioned the sdcard with a modern version of fdisk, the
1st partition will be properly located at 1MiB offset, thus leaving
more than enough space for U-Boot.

Hope this helps. Regards,
Nikolay