Hi Sughosh, On Mon, 28 Oct 2024 at 12:29, Sughosh Ganu <sughosh.g...@linaro.org> wrote: > > On Sun, 27 Oct 2024 at 20:30, Simon Glass <s...@chromium.org> wrote: > > > > Hi Sughosh, > > > > On Fri, 25 Oct 2024 at 13:15, Sughosh Ganu <sughosh.g...@linaro.org> wrote: > > > > > > From: Masahisa Kojima <kojima.masah...@socionext.com> > > > > > > One of the problems OS installers face, when running in EFI, is that > > > the mounted ISO after calling ExitBootServices goes away. For some > > > distros this is a problem since they rely on finding some core packages > > > before continuing the installation. Distros have works around this -- > > > e.g Fedora has a special kernel command line parameter called > > > inst.stage2 [0]. > > > > > > ACPI has NFIT and NVDIMM support to provide ramdisks to the OS, but we > > > don't have anything in place for DTs. Linux and device trees have support > > > for persistent memory devices. So add a function that can inject a pmem > > > node in a DT, so we can use it when launhing OS installers with EFI. > > > > > > [0] > > > https://docs.redhat.com/en/documentation/red_hat_enterprise_linux/7/html/installation_guide/chap-anaconda-boot-options#sect-boot-options-installer > > > > > > Signed-off-by: Masahisa Kojima <kojima.masah...@socionext.com> > > > Signed-off-by: Sughosh Ganu <sughosh.g...@linaro.org> > > > --- > > > boot/fdt_support.c | 41 +++++++++++++++++++++++++++++++++++++++-- > > > include/fdt_support.h | 13 +++++++++++++ > > > 2 files changed, 52 insertions(+), 2 deletions(-) > > > > Can you please use the ofnode interface for this? We are trying not to > > add more of this kind of fixup, as it means someone will have to port > > it over later. > > > > See EVT_FT_FIXUP > > Are you suggesting using the EVT_FT_FIXUP interface for adding the > pmem node? If so, how does this work on platforms which enable > livetree? Looking at the code, I see that the EVT_FT_FIXUP gets called > only when the livetree is not active. However, I am not able to find > any place where the livetree is getting disabled. We do have a > function, oftree_to_fdt() which flattens a livetree, but I don't see > it getting called from anywhere except from a 'upl' command. The > of_root pointer does get set in initr_of_live(), but apart from > dm_test_pre_run(), I do not see where we disable the livetree and set > of_root to NULL. > > So on platforms which do enable livetree, how does this fixup work? > What am I missing?
It isn't implemented yet for OF_LIVE in image_setup_libfdt(). Most of the code is there though. It just needs to be hooked up - see oftree_to_fdt() and oftree_from_fdt(). The idea would be to remove the of_live_active() check, so the event is always sent (will need to 'select EVENT' for OF_LIVE). Then in that same code, after the event, call oftree_to_fdt() and copy the fdt back to blob. If you have time, it should be a nice mini project and will allow us to migrate more things to the ofnode API. Regards, Simon
