Re: [PATCH 08/21] microblaze: get cpu node with of_get_cpu_node

From: Michal Simek <michal.simek@xilinx.com>
To: Rob Herring <robh@kernel.org>, Michal Simek <michal.simek@xilinx.com>
Cc: <devicetree@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 08/21] microblaze: get cpu node with of_get_cpu_node
Date: Tue, 11 Sep 2018 14:15:41 +0200	[thread overview]
Message-ID: <57c78c6e-995d-29cb-fde5-8621610ea9a8@xilinx.com> (raw)
In-Reply-To: <CAL_JsqKWy8dmfF2zCAsEVkDdFM14niKtapqnR_K45Kr3-mZhqQ@mail.gmail.com>

On 10.9.2018 22:49, Rob Herring wrote:
> On Mon, Sep 10, 2018 at 9:56 AM Michal Simek <michal.simek@xilinx.com> wrote:
>>
>> On 5.9.2018 21:37, Rob Herring wrote:
>>> "device_type" use is deprecated for FDT though it has continued to be used
>>> for nodes like cpu nodes. Use of_get_cpu_node() instead which works using
>>> node names by default. This will allow the eventually removal of cpu
>>> device_type properties.
>>>
>>> Also, fix a leaked reference by adding a missing of_node_put.
>>>
>>> Cc: Michal Simek <monstr@monstr.eu>
>>> Signed-off-by: Rob Herring <robh@kernel.org>
>>> ---
>>> Please ack and I will take via the DT tree. This is dependent on the
>>> first 2 patches.
>>
>> I have tested it and it is align with the spec and all dtses generated
>> before 2015 will work without any issue.
>> In 2015 new device tree generator was introduced and it is not adding
>> reg property to cpu node which is required by this change.
>> This will be fixed but that means that all generated dtses from 2015 are
>> affected.
> 
> Patch 2 was supposed to handle that case. However, it does expect that
> there should be an #address-cells equal to 0 in that case. Is that not
> a valid assumption?

as you can expect we have

#address-cells = <0x1>;
#cpus = <0x1>;
#size-cells = <0x0>;
cpu@0 {
	/* no reg property */
};

That missing reg property was even reported by dtc but none has fixed
that. This will be fixed for xilinx releases.

>> That's why will be great if you can also change that pr_err message to
>> mentioned to also check reg property to give users a chance to fix it
>> properly. Error log below.
> 
> I don't think breaking users is good.
> 
> I could make this a find by path (/cpus/cpu) instead or just drop it
> for microblaze. It doesn't really affect my plans for removing
> device_node.type ptr.

If this is fine for you that will be the best solution.

Thanks,
Michal