[meta-ti] Getting Started with meta-ti "rocko" and beaglebone black (BBB)

[William Mills]

On 08/28/2018 10:58 AM, Leo Meza wrote:
> Thanks Bill/Denys,
> 
> I was getting errors when trying to build with am335x-evm machine,

Can you report what error you had? I tried to reproduce your conditions
and built and booted core-image-minimal with this machine just fine.

I think solving the issue with am335x-evm is a much better way to go.

> so I
> stayed with beaglebone machine since it at least let me complete a
> build. I'm still getting the repeating messages at the serial console,

Yes, I did also with the beaglebone machine.  You are suppose to see the
banner from SPL (MLO) and then a banner from U-boot (u-boot.img).  The
fact that we don't see the U-boot banner means U-boot is not getting
loaded or not running.  (It is resetting and staring over with SPL).

Until you see that U-boot message, what you do with zImage and dtbs is
irrelevant.

I am not sure what is broken in SPL for the beaglebone configuration.  I
did take a look and nothing jumped out at me.
Again am335x-evm works.

> here are my steps, maybe I'm still doing something wrong.
> 1. Poky is at rocko branch 2731fd3
> 2. meta-ti is at rocko branch b38fd82
> 3. Replaced meta-yocto-bsp with meta-ti in bblayers.conf
> 4. Set MACHINE ?= "beaglebone" in local.conf
> 5. Build with "bitbake core-image-minimal"
> 6. sudo cp MLO $BOOT
> 7. sudo cp u-boot.img $BOOT
> 8. sudo tar -xf core-image-minimal-beaglebone.tar.xz -C $ROOT
> 9. sudo cp zImage $ROOT/boot
> 10. sudo cp am335x-boneblack.dtb $ROOT/boot
> 11. sudo tar -xvzf modules-beaglebone.tgz -C $ROOT
> 12. Did not use uEnv.txt and did not change environment variables
> 
> Not sure if I did this part right because I don't know what is meant by
> "short form *.dtbs":
> "Put zImage and the short form *.dtbs in root partitions' /boot dir"
> 

You can copy all the dtbs if you wish. The bootloader used the ones with
names like am335x-boneblack.dtb and ignores ones like
zImage-am335x-boneblack.dtb and zImage--4.14.*-am335x-boneblack.dtb.

If you do copy just the short form you need to follow symlinks so you
actually have the files.

(When I tested beaglebone I just dd the wic image to the SD card.  The
explict steps above were for am335x-evm since it does not create a wic
image)

Bill


> Any further tips/pointers would be appreciated.
> 
> Thanks in advance,
> Leo
> 
> On Thu, Aug 23, 2018 at 6:42 PM William Mills <wmills at ti.com
> <mailto:wmills at ti.com>> wrote:
> 
>     Leo,
> 
>     On 08/22/2018 02:18 PM, Leo Meza wrote:
>     > I'm learning yocto and was able to easily boot my BBB with a
>     > core-image-minimal system using the meta-yocto-bsp layer. However,
>     when
>     > I removed that layer and tried with meta-ti, I just see this on the
>     > Putty serial console, it repeats over an over:
>     >
>     > U-Boot SPL 2018.01-g6d540394a4 (Aug 22 2018 - 16:33:01)
>     > Trying to boot from MMC1
>     > *** Warning - bad CRC, using default environment
>     >
> 
>     I was able to duplicate this result when using meta-ti to build the
>     "beaglebone" machine.
> 
>     TI builds and test the am335x-evm machine for all am335x based boards
>     inlcuding beaglebone.  If you switch to this machine you should have
>     better luck.
> 
>     Note that as Denys said elsewhere TI images and default u-boot variable
>     settings assume that the kernel is in the root partition not the boot
>     partition.  The _path_ in the root partition should be /boot/zImage
> 
>     The only thing you need in the boot partition is MLO and the u-boot.img.
>     If you want to override the u-boot settings you can have a uEnv.txt file
>     there.  Also if you save the environment from within u-boot it will end
>     up as a file in the boot partition named uboot.env
> 
>     I notice that the am335x-evm machine does not create a .wic image so you
>     will have to assemble the parts from the deploy dir.
>     Put MLO and u-boot.img in the boot partition
>     untar the rootfs tar ball to the root partition
>     Put zImage and the short form *.dtbs in root partitions' /boot dir
>     untar the modules tar ball in the root partition.
> 
> 
>     > I'm copying MLO, zImage, u-boot.img, and am335x-boneblack.dtb to the
>     > BOOT (1st) partition of my uSD card. Then extracting
>     > core-image-minimal-beaglebone.tar.xz -C to the ROOT (2nd) partition of
>     > my uSD card. This works fine when using meta-yocto-bsp, but not with
>     > meta-ti. So, if anyone can help me understand what the different steps
>     > are between using the two different layers, I'd greatly appreciate it.
>     > Spent several days trying to figure this out so far.
>     >
>     > Thanks in advance,
>     > Leo
>     >
>     >
> 
>     Denys,
> 
>     The beaglebone machine creates a much smaller MLO (~75K vs 109K) and
>     u-boot.img.
>     When you boot the image the SPL just spits out the message above over
>     and over.  It never gets to u-boot.
> 
>     To reproduce I started with a clean clone of poky
>     added a clean clone of meta-ti
>     checked out rocko for both
>     . oe-*
>     edit conf/bblayers to take out yocto-bsp (for safty sake)
>     added meta-ti
>     built core-image-minimal for beaglebone machine.
> 
>     Bill
>