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

[Joachim Eastwood]

On 31 March 2016 at 18:31, Rob Herring <robh+dt at kernel.org> wrote:
> On Thu, Mar 31, 2016 at 11:27 AM, Rob Herring <robh+dt at kernel.org> wrote:
>> On Wed, Mar 30, 2016 at 11:15 AM, Joachim  Eastwood <manabian at gmail.com> wrote:
>>> Hi Mark,
>>>
>>> On 30 March 2016 at 15:41, Mark Rutland <mark.rutland at arm.com> 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 at 0.
>>
>> Except memory is probably not actually at 0 here. This has come up
>> before and been beaten to death. Bottom line is plain "memory" is
>> allowed, and I plan to add that exception to dtc.

Okey, good.


>>>> 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.
>>
>> You've got to make sure they have 'device_type = "memory";' which they
>> could rely on inheriting.
>
> BTW, you could add this as a check to dtc and then it will find all
> the missing ones for you.

I have created a script now that will check and add it if it is missing.


regards,
Joachim Eastwood