[PATCH 1/2] of: addr: Abort address translation for parent nodes missing 'ranges'

[Dario Binacchi]

> Il 15/03/2021 19:23 Simon Glass <sjg at chromium.org> ha scritto:
> 
>  
> +Tom Rini too
> 
> 
> On Tue, 16 Mar 2021 at 03:48, Bin Meng <bmeng.cn at gmail.com> wrote:
> >
> > +Dario Binacchi
> >
> > On Mon, Mar 15, 2021 at 3:11 PM Simon Glass <sjg at chromium.org> wrote:
> > >
> > > Hi Bin,
> > >
> > > On Wed, 3 Mar 2021 at 14:54, Simon Glass <sjg at chromium.org> wrote:
> > > >
> > > > On Fri, 26 Feb 2021 at 00:36, Bin Meng <bmeng.cn at gmail.com> wrote:
> > > > >
> > > > > The implementation of of_translate_one() was taken from the one in
> > > > > Linux kernel drivers/of/address.c, and the Linux one added a quirk
> > > > > for Apple Macs that don't have the <ranges> property in the parent
> > > > > node. Since U-Boot does not support Apple Macs, remove the comment
> > > > > block and adhere to the spec to abort the translation.
> > > > >
> > > > > Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
> > > > > ---
> > > > >
> > > > >  drivers/core/of_addr.c | 24 ++++++------------------
> > > > >  1 file changed, 6 insertions(+), 18 deletions(-)
> > > >
> > > > Reviewed-by: Simon Glass <sjg at chromium.org>
> > >
> > > Unfortunately this seems to cause a test failure for
> > > ut_dm_fdt_translation. Can you please take a look?
> >
> > It seems the no "ranges" property was intentionally removed by the
> > following commit:
> >
> > commit d64b9cdcd475eb7f07b49741ded87e24dae4a5fc
> > Author: Dario Binacchi <dariobin at libero.it>
> > Date:   Wed Dec 30 00:16:21 2020 +0100
> >
> >     fdt: translate address if #size-cells = <0>
> >
> >     The __of_translate_address routine translates an address from the
> >     device tree into a CPU physical address. A note in the description of
> >     the routine explains that the crossing of any level with
> >     since inherited from IBM. This does not happen for Texas Instruments, or
> >     at least for the beaglebone device tree. Without this patch, in fact,
> >     the translation into physical addresses of the registers contained in the
> >     am33xx-clocks.dtsi nodes would not be possible. They all have a parent
> >     with #size-cells = <0>.
> >
> > It looks the commit was needed for beaglebone board.
> >
> > Dario, could you please comment on why U-Boot needs to done like this,
> > while Linux kernel has this check? Is the beaglebone board not working
> > in Linux?
> >

Beaglebone is working in Linux, but I think Linux walks the device tree less 
fully than u-boot. 
I was surprised by the address translation error when traversing nodes with 
size cells 0. And for this reason I added the CONFIG_OF_TRANSLATE_ZERO_SIZE_CELLS 
symbol to fix the issue, not enabled by default, thus making the change backwards
compatible.

Thanks and regards,
Dario

> > Regards,
> > Bin