[PATCH 1/2] DM_USB: allow building without OF_CONTROL

Tom Rini trini at konsulko.com
Mon Jun 28 15:39:27 CEST 2021


On Sun, Jun 27, 2021 at 01:06:12PM -0600, Simon Glass wrote:
> Hi Pali,
> 
> On Fri, 25 Jun 2021 at 10:58, Pali Rohár <pali at kernel.org> wrote:
> >
> > On Friday 25 June 2021 10:43:11 Simon Glass wrote:
> > > Hi Pali,
> > >
> > > On Fri, 25 Jun 2021 at 10:16, Pali Rohár <pali at kernel.org> wrote:
> > > >
> > > > On Friday 25 June 2021 10:04:14 Simon Glass wrote:
> > > > > 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.
> > > >
> > > > Patches in this series were written by Ivo. I do not know exact details
> > > > and numbers. But the fact is that it was required to enable thumb-2 mode
> > > > (which has hw bugs on this cpu, see earlier emails; reason why it was
> > > > disabled). If you want to investigate it, you can try compare u-boot
> > > > from master/next and u-boot with applying these patches + disable
> > > > thumb-2 mode. Note that we have already enabled LTO.
> > > >
> > >
> > > That's probably a little beyond my level of enthusiasm. But if you are
> > > able to push a tree with before/after commits, I will take a look.
> >
> > Hello Simon! I have already pushed these patches to github due to CI
> > testing. So you can easily access them via git fetch/checkout.
> >
> > Before (this is already in u-boot git):
> > $ git checkout a298d4fbcdba1b38e48ea2af0fc5386cab2070da
> >
> > After1:
> > $ git fetch https://github.com/u-boot/u-boot.git refs/pull/83/head
> > $ git checkout 1f038c8b45ef0018e52a2a4587eb73170769ac2f
> >
> > After2:
> > = use After1 with:
> >   + disable CONFIG_SYS_THUMB_BUILD
> >   + enable CONFIG_OF_LIBFDT_OVERLAY
> >   + enable CONFIG_CMD_FDT
> >
> > defconfig file is nokia_rx51_defconfig
> 
> OK thanks, I see it. I pushed a tree to u-boot-dm/nokia_rx51 with a
> few changes. The growth is about 19KB (without enabling Thumb). Some
> more fine-grained control of what get enabled with LIBFDT could be
> added to reduce that, perhaps by 5KB.

So, was the entirety of the reduction you saw from dropping out
EFI_LOADER?  Just most of it?  Disabling that came up in another part of
this thread.  And if we just need to disable EFI_LOADER,
OF_LIBFDT_OVERLAY and CMD_FDT (and maybe tweak the mask value) in order
to not need to do any other changes, yes, that's the right approach.  It
would be helpful, but not required, to confirm if thumb works or fails
on hardware, but I do understand it's a PITA to unbrick these devices.

-- 
Tom
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