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Message-id: <536C8B63.3000400@samsung.com>
Date: Fri, 09 May 2014 10:01:39 +0200
From: Tomasz Figa <t.figa@...sung.com>
To: Chanwoo Choi <cw00.choi@...sung.com>,
Tomasz Figa <tomasz.figa@...il.com>
Cc: kgene.kim@...sung.com, linux-kernel@...r.kernel.org,
linux@....linux.org.uk, ben-linux@...ff.org, arnd@...db.de,
olof@...om.net, marc.zyngier@....com, thomas.abraham@...aro.org,
kyungmin.park@...sung.com, inki.dae@...sung.com,
sw0312.kim@...sung.com, hyunhee.kim@...sung.com,
yj44.cho@...sung.com, chanho61.park@...sung.com,
sajjan.linux@...il.com, tushar.behera@...aro.org,
sachin.kamat@...aro.org, linux-samsung-soc@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
Jaehoon Chung <jh80.chung@...sung.com>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
Rob Herring <robh+dt@...nel.org>,
Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>
Subject: Re: [PATCHv4 7/7] ARM: dts: Add device tree sources for Exynos3250
On 09.05.2014 09:10, Chanwoo Choi wrote:
> Hi Tomasz,
>
> On 05/09/2014 02:02 PM, Tomasz Figa wrote:
>> Hi Chanwoo,
>>
>> On 09.05.2014 03:06, Chanwoo Choi wrote:
>>> On 04/26/2014 09:51 AM, Tomasz Figa wrote:
>>>> On 25.04.2014 03:16, Chanwoo Choi wrote:
>>
>> [snip]
>>
>>>>> + cpus {
>>>>> + #address-cells = <1>;
>>>>> + #size-cells = <0>;
>>>>> +
>>>>> + cpu@0 {
>>>>> + device_type = "cpu";
>>>>> + compatible = "arm,cortex-a7";
>>>>> + reg = <0>;
>>>>> + clock-frequency = <1000000000>;
>>>>> + };
>>>>
>>>> Why only one CPU? I believe Exynos3250 is dual core.
>>>
>>> I'll add cpu1 information.
>>>
>>>> Also are physical IDs of the cores really 0 and 1? On Exynos4210 for example they are 0x900 and 0x901, while on Exynos4212 they are 0xa00 and 0xa01. Please check this.
>>>
>>> The 'reg' property means only hardware id(hwid) of CPU.
>>> You can check it on arm_dt_init_cpu_maps() in arch/arm/kernel/devtree.c.h.
>>> or Documentation/devicetree/bindings/arm/cpus.txt.
>>>
>>
>> Well, as described in Documentation/devicetree/bindings/arm/cpus.txt, on 32-bit ARM v7 or later CPUs the "reg" property should be equal to the lower 24-bits of MPIDR value of given CPU, which in addition to core ID includes also cluster ID, which can be non-zero, even on single cluster SoCs (like it is on Exynos4210 and 4x12).
>
> I checked the lower 24-bit of MPIDR value for Exynos3250 in arm_dt_init_cpu_maps().
> - the lower 24-bit of MPIDR for CPU0 is '0x0'.
Fair enough. Thanks.
Best regards,
Tomasz
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