On Tue, Feb 18, 2014 at 7:07 PM, <[email protected]> wrote:
> Hey guys,
>
> I'm working on a project which is using a clone of the BBB hardware and
> I'm running into some issues with Device Trees. I wasn't involved with the
> hardware design, but as far as I know, the BBB hardware has been duplicated
> exactly. Specifically, the clone board will be directly connected to an LCD
> using the LCD data pins on the AM335x. I've never worked with Device Trees
> before, but after some initial research (mostly based on this
> summary<http://learn.adafruit.com/introduction-to-the-beaglebone-black-device-tree/overview>)
> I'm thinking that they are the best way to accomplish what I'm looking for
> (enabling the LCD pins and configuring the driver to use them). I'm not
> concerned about the details of implementing this right now, since I'm
> having issues with Device Trees in general that I need to address first.
>
> The board is booting from an SD card with two partitions: one for U-boot
> and one for the Angstrom (v2012.12 with 3.8.13 kernel) image, both of which
> are the standard images which ship with the Beaglebone. I'm not having
> problems getting the board to boot. It has no problem running U-boot and it
> can start Linux without any catastrophic failures using the default images.
> Once Linux boots, if I go to /sys/devices/bone_capemgr.8, there are all the
> files you'd find on a regular BBB *except *slots and the slots-* files.
> As far as I know, without these files I can't add or modify device trees
> for the board. I still could by rebuilding the kernel I suppose, but as far
> as I know this is a deprecated approach.
>
> Here's a pastebin showing the serial output of the clone while it
> boots<http://pastebin.com/ZBmatVgk>
>
> I only have a basic understanding of U-Boot, so the output during the boot
> sequence doesn't help me to much, but here are the main things I've noticed
> while skimming through it:
>
> 1. Right at the start of the SPL process, the magic number check in EEPROM
> fails. This makes sense since the cloned board has a blank EEPROM. I'm not
> sure if this is a problem, but the assumption in the next lines (Beaglebone
> LT/Black.musb-hdrc) seem to work. The board is able to get past the SPL
> stage so I'd figure that this assumption is accurate enough.
>
There are some rather basic configuration components that require board
detection to work. I suggest you hard-code it in the SPL/u-boot or program
the EEPROM.
>
> 2. The main U-Boot process also checks the EEPROM and fails the ID check.
> There is no reassuring message this time ("Assuming Beaglebone" or
> something to that effect) so I'm not sure if this is a larger problem.
>
> 3. The PHY initialization fails. The only hardware difference I know of
> between the clone and the BBB is the PHY, so this isn't very surprising.
> I'm pretty sure the PHY uses a different address so I'll deal with this
> when it becomes an issue.
>
> 4. The uEnv.txt is being read. I originally thought this might have been a
> problem, but if I modify uEnv.txt U-boot reports the correct file size. In
> this example I'm just using the default one though.
>
> 5. U-boot mentions the device tree addresses, but I don't know if there is
> any significance to this.
>
> 6. While booting the kernel, U-boot throws some bone-capemgr errors
> relating to the EEPROM. This makes me think that the EEPROM failure might
> be messing up the device tree configuration through bone-capemgr but I'm
> not sure. There are also some GPIO mux errors but I'm not sure that they
> really matter for my problems right now.
>
> That's all I've got right now. As I said, this is my first time working
> with anything related to the BBB and I don't really have any experience
> with U-Boot, so unfortunately I'm mostly relying on support from you guys
> at this point. If you need any more information just let me know.
>
> Thanks,
>
> --
> For more options, visit http://beagleboard.org/discuss
> ---
> You received this message because you are subscribed to the Google Groups
> "BeagleBoard" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to [email protected].
> For more options, visit https://groups.google.com/groups/opt_out.
>
--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups
"BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
For more options, visit https://groups.google.com/groups/opt_out.
