raspberry BSP: Maybe there is a bug in the linker file?

[Christian Mauderer]

On 19/12/2019 14:27, Sebastian Huber wrote:
> On 19/12/2019 14:24, Christian Mauderer wrote:
>> Hello,
>>
>> triggered by the discussion regarding RTEMS on raspberrypi 3 I did some
>> tests. I haven't been able to start a RTEMS on my Pi 1 if I tried a
>> version after commit c5fd79cd4704a4270ba0114a1009ab8556f997c9 from
>> 29.07.2019. Right before it everything works as expected.
>>
>> The commit changes the memory locations. From what I understood, the
>> bootloader on a raspberry always jumps to address 0x8000 after loading
>> the application. So I'm not convinced that the change is correct.
> 
> Is the 0x8000 a fixed address or you configure this in a boot image header?
> 

>From what I've seen the bootloader just uses a fixed address. All guides
that I've found just use objcopy to generate a binary from the elf files
without adding a header. For example a guide for RTEMS:


http://alanstechnotes.blogspot.com/2013/03/running-your-first-rtems-program-on.html

A FreeRTOS port mentions this behavior explicitly in a comment in the
linker file:


https://github.com/jameswalmsley/RaspberryPi-FreeRTOS/blob/master/raspberrypi.ld#L17

The "graphics processor" is no typo here. It seems the initialization is
really done by the graphics processor on the pi.