BCM2836 (Raspberry Pi 2) port

Eric Anholt eric at anholt.net
Mon Apr 27 10:19:58 PDT 2015


Stephen Warren <swarren at wwwdotorg.org> writes:

> On 04/24/2015 12:41 PM, Eric Anholt wrote:
>> Stephen Warren <swarren at wwwdotorg.org> writes:
>>
>>> On 04/21/2015 12:09 PM, Eric Anholt wrote:
>>>> This is my first submission of a Raspberry Pi 2 port.  It can be found
>>>> at https://github.com/anholt/linux/tree/bcm2836
>>>>
>>>> I'm using the 2835 interrupt controller support, without adding the
>>>> checks for ARM local interrupts first.  That means no support for IPIs
>>>> (and thus no SMP), no PMU events, and no local timer (I'm using the
>>>> same 2835 peripheral one).
>>>>
>>>> It supports a similar featureset to Pi 1 at this point.  Serial and SD
>>>> cards work.  Just one CPU supported.  USB (ethernet) works if you use
>>>> U-Boot, or my mailbox series
>>>> (https://github.com/anholt/linux/tree/bcm2836-mbox).
>>>
>>> I can't quite get this to work. I think what's happening is that U-Boot
>>> is over-writing the location of the code/data that the CPU1..3 pin loop
>>> uses. Do you know what that address is so I can confirm that?
>>>
>>> I suspect this because when I load the kernel/DT in U-Boot, or when I
>>> jump to the kernel to boot it, I see lots of extra duplicated characters
>>> on the UART, like all 4 CPUs are booting Linux. For example:
>>
>> Oops, I was just extrapolating that U-Boot would work.  I've quit using
>> it because of the extra configuration work (particularly the compiled
>> text files for the boot scripts).
>
> You don't need any compiled text files if you create an extlinux.conf 
> rather than a boot.scr. extlinux.conf is plain text.
>
> To boot without U-Boot: Could you say what's in your config.txt? I 
> assume I can just copy the kernel zImage as kernel.img, and the DTB from 
> the kernel build tree without renaming it?

I've been explicitly naming the DTB in config.txt, haven't tested otherwise.
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