Re: [PATCH 2/7] ARM: dts: skeleton: add unit name to memory node

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Hi Mark,

On 30 March 2016 at 15:41, Mark Rutland <mark.rutland@xxxxxxx> wrote:
> On Wed, Mar 30, 2016 at 04:06:56PM +0300, Vladimir Zapolskiy wrote:
>> On 30.03.2016 14:06, Mark Rutland wrote:
>> > On Wed, Mar 30, 2016 at 12:30:41AM +0200, Joachim Eastwood wrote:
>> >> Add unit name to memory to remove the following warning:
>> >>  Warning (unit_address_vs_reg): Node /memory has a reg or ranges
>> >>                            property, but no unit name
>> >
>> > If anything, it would be better to get rid of the memory node from the
>> > skeleton DTs.
>> >
>> > For DTs which have a memory node there's no problem, and DTs which
>> > expect a bootlaoder to fill things in have a logical place to document
>> > that fact.
>
>> The only problem I see if DTB is updated on a board but a board bootloader
>> on fix-up is capable to fill a preexisting "/memory" device node in only,
>> otherwise it is not clear why the device node is present in skeleton.dtsi.
>
> Sure. To clarify the above, what I expect that for this case is that the
> empty memory node would exist in the dts for that particular board,
> along with a comment, e.g.
>
>         /* The firmware/bootloader for $BOARD fills this in */
>         memory {
>                 device_type = "memory";
>                 reg = <0 0 0 0>;
>         };

To avoid the warning with the new dtc this would need to be memory@0.


> That way you can tell at a glance that the lack of memory information in
> the DT for a board is intentional, and the bootloader still gets the
> node it expects.


But this doesn't seem to be a "problem" with any of the DTs in
arch/arm/boot as they all defined a memory node.

I used the following script to check for the memory node in all built dtb's.
  make ARCH=arm CONFIG_OF_ALL_DTBS=y dtbs
  for i in $(ls arch/arm/boot/dts/*.dtb); do
         m=$(scripts/dtc/dtc -I dtb -O dts $i | grep -m1 'memory.*{')
         if [ -z "$m" ]; then
                 echo "Missing memory node in $i"
          fi
  done

So it should be pretty safe to just remove the memory node entry in
the skeleton files. Unless I have missed something with the script
above.


regards,
Joachim Eastwood
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