Hi Pali, On Fri, 25 Jun 2021 at 07:07, Pali Rohár <p...@kernel.org> wrote: > > On Friday 25 June 2021 08:38:47 Tom Rini wrote: > > On Sun, Jun 20, 2021 at 09:43:43PM +0200, Marek Vasut wrote: > > > On 6/20/21 5:54 PM, Tom Rini wrote: > > > > > > [...] > > > > > > > > As far as I understand, the RX51 has gigabytes of eMMC storage, so it > > > > > can > > > > > use SPL just like any other OMAP3 board. > > > > > > > > U-Boot is being called by the old vendor X-Loader fork and needs to take > > > > up the existing flash spot. > > > > > > So, why not place SPL in those 256 kiB and load U-Boot proper from the > > > eMMC > > > ? > > > > > > > > > So we need to make > > > > > > changes in subsystems they use so that they can continue to work. > > > > > > > > > > > > So, are the changes being proposed to the generic USB code, such > > > > > > that > > > > > > DM_USB can be enabled, and when DM_USB_GADGET gets a deadline (Note, > > > > > > that's not set yet, but that's not to say never, it's just not been > > > > > > set, > > > > > > so getting ahead of problems here would be appreciated) that can > > > > > > also be > > > > > > enabled, OK? > > > > > > > > > > I am confused by this reply. I noticed a lot of boards were removed > > > > > over > > > > > time because they were not converted to DM/DT, and to get rid of all > > > > > the > > > > > ifdefs, but now it seems the direction has been completely reversed > > > > > and we > > > > > should start adding back all the ifdefs to cater for boards which are > > > > > not > > > > > converted instead of fixing the boards ? > > > > > > > > A lot of boards are being removed because no one wants to update and > > > > maintain them and they have likely not been run-time tested in years. > > > > Trying to clean up the code in those cases is best done by removing the > > > > platform, as no one using it. That is not the case here. > > > > > > Note that there have been boards which had to be switched to SPL to even > > > permit converting them to DM/DT, and thus prevent removal. > > > > > > > If your only > > > > concern about the approach taken is some #ifdef's in the code, do you > > > > want to see them converted to use some wrapper macro like we do in a few > > > > other cases and __maybe_unused some functions as needed? > > > > > > I think there is a better option which does not add any ifdefs at all > > > _and_ > > > is future-proof -- place SPL in those 256 kiB, load U-Boot from eMMC and > > > then enable all the functionality you might need in U-Boot. That would > > > free > > > you from dealing with the size limitations basically indefinitely. > > > > So, at this point I'm waiting for either of: > > - A response to Marek's questions about using SPL, from the Nokia NX51 > > folks. > > Hello Tom! Here is my answer: > > > So, why not place SPL in those 256 kiB and load U-Boot proper from the eMMC > > ? > > U-Boot for N900 does not use SPL. There is no SPL code implemented. > Nobody ever tried to implement it and neither tested. As you have > correctly pointed instead of SPL is used vendor X-Loader binary, which > is signed by RSA key. > > Add eMMC: On eMMC is stored existing operating system, which somehow > also interacts with vendor X-Loader. There was no big investigation on > this topic. Also direct booting from eMMC is not supported (unless you > crack RSA, figure out how secure things work and generate compatible > image) and neither from existing X-Loader (because vendor did not > enabled it). There is no easy access to eMMC until you start full > U-Boot. So even if all these problems are solved then "bootstrapping" or > flashing U-Boot into such location is not possible, plus there is no > recovery. Plus this loose existing and working operating system, which > is no-go. So this way is basically undebugable and therefore perfectly > hard to develop.
I don't want to inject myself in this discussion, although it does sound like this platform should use SPL. But I do wonder about the 100KB growth you saw with DT/DM. That seems absolutely enormous to me! Can you please point me to the git tree for this? I'd like to investigate. - Simon > > Not mentioning that implementing this means to implement all N900 code > in U-Boot from scratch. And the last thing is testing... > > For me this idea looks like total perfectionism in corporate world when > some software architect invent a new super-duper-über solution for > everything which in reality is not possible to implement. > > PS: In past few people investigated topic on cracking RSA signature on > Omap3 and nobody was able to find any "security issue" in it... > > > - A patch to rework things so that USB gadget support more cleanly > > removes from the code paths non-gadget code, so there's no #if's being > > added here. Or some similar clean-up. > > > > -- > > Tom > >
