Hii, It has been quite a few days since the last mail. Chris, can you please take a look at this when you are free?
Thanks, Niteesh On Mon, Mar 23, 2020 at 1:23 AM Christian Mauderer <l...@c-mauderer.de> wrote: > Hello Niteesh, > > thanks for the (private) remainder. This thread really stopped quite > some time ago. A lot of us are quite busy right now but that shouldn't > happen. If you don't get a response for some question: Please give it > about a week of time and then just ping the thread. > > On 05/03/2020 11:06, G. S. Niteesh wrote: > > On Wed, Feb 26, 2020 at 8:39 AM Chris Johns <chr...@rtems.org > > <mailto:chr...@rtems.org>> wrote: > > > > On 22/2/20 1:45 am, G. S. Niteesh wrote: > > > Hi, > > > > > > This is regarding adding RPi support to the boot image generation > > tool. > > > > > > The boot process for Raspberry Pi is very unconventional. The GPU > > starts > > > first, initializes RAM, other hardware, loads the bootloaders and > > then starts > > > the ARM CPU. > > > > > > The minimum files that are required to boot an RPi are > > > bootcode.bin, startx.elf, fixup.dat, kernel.img, config.txt > > > There are also other variants of startx.elf and fixup.dat. > > > Please have a look > > > > > at > https://www.raspberrypi.org/documentation/configuration/config-txt/boot.md > > > for information on the variants. > > > > > > From what I have tried on my Rpi3 model b v1.2 the minimum files > > that are > > > required are start_x.elf, fixup_x.dat, bootcode.bin, kernel.img, > > config.txt > > > But for this to work, we must add start_x=1 to config.txt because > > by default > > > start.elf is loaded. > > > > Hello Chris, > > > > > > I would have look at how the tool maps to RPi to know if it needs > > more work :) > > > > > > Did you take a look at it? > > Chris is most likely too busy with the release right now. > > > > > In my opinion, there are two ways to do it. > > The first would be to modify the U-Boot bootloader object to have a > > files field > > to make sure the user provides all the necessary files(fixup.dat, > > startx.elf, config.txt). > > So after this change the rtems-boot.ini for RPI should look something > > like this > > [u-boot-raspberrypi] > > uses = u-boot-arm-raspberrypi > > .. > > .. > > first_stage = %{ubootdir}/bootcode.bin > > boot_device = mmc 0 > > second_stage = uboot or startx > > files = [config.txt, fixup.dat etc] > > But also please keep in mind that if we want to support RPi4 then the > > first_stage > > will start4x.elf since bootcode.bin is now replaced by code in the > > EEPROM in RPi4 SOC. > > As far as I understand that approach it more or less tells: To start a > raspberry you need U-Boot. U-Boot needs the fixup.dat, startx.elf and > config.txt to boot. But that sounds a bit wrong. On Raspberry U-Boot is > purely optional, isn't it? So from a high-level view it would be more a > > - Raspberry needs fixup.dat, startx.elf and config.txt > - That can start either: > - an application or > - an U-Boot which can then start an application (or do other things) > > > > > Another approach will be to create the default Raspberry Pi bootloader > > object. But having > > support for U-Boot is important since it will allow for automatic > testing. > > That approach sounds more correct. But I don't really know the > rtems-boot-image tool. That makes it a lot harder for me to tell whether > that approach works well. From that ignorant position I would say that > it would be nice to have a boot-image command that can be called with or > without a option (like --with-u-boot). Alternatively maybe two targets > would be possible. One raspiboot-u-boot-pi1 and one raspiboot-raw-pi1. > > But your best bet might is to wait for Chris to get free again and > answer that question. He knows the boot image tool and can tell you a > lot better which concept works best. > > Best regards > > Christian > > > > > Which one do you think is a better approach? > > > > Thank you. > > > > > > > > > > So, what should be the values for the first and second stages in > > rtems-boot.ini > > > for Rpi? > > > > Would this be bootcode.bin? > > > > > And also wouldn't it be nice if we could add a files field, which > > will copy the > > > specified files to the image? This would save a lot of typing in > > case of RPi > > > > Do you have an example? > > > > Chris > > > > > > _______________________________________________ > > devel mailing list > > devel@rtems.org > > http://lists.rtems.org/mailman/listinfo/devel > > >
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