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

[Christian Mauderer]

I haven't had a look at the different types of UARTS yet. What is the
difference? What do you use as reference?

If it is just a variant of an existing driver, the existing one should
be extended to support both variants.

On 21/12/2019 20:45, Niteesh wrote:
> On inspecting the code, the driver is for PL011. We have to write a
> driver for the mini uart.
> which we will have start from scratch. So, how do you want the structure
> to be?
> 
> The code of PL011 can be improved. We could use gpio functions to
> configure pins.
> And also many of the UART values are set in place instead of using the
> appropriate function, for example
> the usart_set_baud is empty and the baud rate is set directly in the
> init function.
> What do you think about these changes? Should we change them also?
> On Sun, Dec 22, 2019 at 12:25 AM Christian Mauderer <list at c-mauderer.de
> <mailto:list at c-mauderer.de>> wrote:
> 
>     On 21/12/2019 19:26, Niteesh wrote:
>     > There is already a PL011 driver in the arm shared section. should we
>     > just import it?
> 
>     If you say "import" and you mean "use" and not "copy": yes, that would
>     be great.
> 
>     >
>     > On Sat, Dec 21, 2019 at 10:46 PM Niteesh <gsnb.gn at gmail.com
>     <mailto:gsnb.gn at gmail.com>
>     > <mailto:gsnb.gn at gmail.com <mailto:gsnb.gn at gmail.com>>> wrote:
>     >
>     >     Shall I start writing a driver for raspberrypi3 PL011?
>     >
>     >
>     >     On Sat, Dec 21, 2019 at 8:40 PM Christian Mauderer
>     >     <list at c-mauderer.de <mailto:list at c-mauderer.de>
>     <mailto:list at c-mauderer.de <mailto:list at c-mauderer.de>>> wrote:
>     >
>     >         On 19/12/2019 15:05, Christian Mauderer wrote:
>     >         > 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.
>     >         > _______________________________________________
>     >         > devel mailing list
>     >         > devel at rtems.org <mailto:devel at rtems.org>
>     <mailto:devel at rtems.org <mailto:devel at rtems.org>>
>     >         > http://lists.rtems.org/mailman/listinfo/devel
>     >         >
>     >
>     >         I just found an option: It is possible to set a
>     "kernel_address"
>     >         in the
>     >         config.txt:
>     >
>     >
>     >       
>      https://www.raspberrypi.org/documentation/configuration/config-txt/boot.md
>     >
>     >         So the start address can be changed and maybe the adaption to
>     >         the linker
>     >         file isn't necessary.
>     >
>