[yocto] [meta-raspberrypi][PATCH v2] u-boot: Simplify boot script

[Jonathan Liu]

Hi Paul,

On 5 November 2016 at 06:12, Paul Barker <paul at paulbarker.me.uk> wrote:
> On Sat,  5 Nov 2016 00:47:34 +1100
> Jonathan Liu <net147 at gmail.com> wrote:
>
>> A patch is added to check if the firmware loaded a device tree blob
>> into memory and set the fdt_addr_r variable if it is found. The U-Boot
>> script will then read the command line arguments generated by the
>> firmware from the device tree and boot the kernel with the command
>> line arguments and the loaded device tree.
>>
>> This allows things like MAC address, board revision and serial number
>> to be correctly configured and options in config.txt to be used.
>>
>> Signed-off-by: Jonathan Liu <net147 at gmail.com>
>> ---
>> Changes in v2:
>>  - Instead of setting device_tree_address to 0x100 in config.txt, patch
>>    U-Boot to detect the device tree blob address if it was loaded.
>>
>
> I've tested this on the HW I have access to but I'm still running into
> problems.
>
> RaspberryPi B+: Fails with "Could not find a valid device tree"
> message. I need to debug this further.
>
> RaspberryPi 3: Boots successfully. However "earlyprintk" is missing
> from the bootargs so we miss kernel messages which may be useful for
> debug.

You can do one of the following:
- Add CMDLINE_append = " earlyprintk" to local.conf or distro conf
- Modify cmdline.txt on the SD card boot partition and add earlyprintk

I didn't want to make any assumptions.

Regards,
Jonathan