From mboxrd@z Thu Jan  1 00:00:00 1970
From: t.figa@samsung.com (Tomasz Figa)
Date: Fri, 11 Apr 2014 09:14:53 +0200
Subject: [PATCH 04/27] ARM: EXYNOS: Support secondary CPU boot of
 Exynos4212
In-Reply-To: <006f01cf554b$dbc6a2d0$9353e870$@samsung.com>
References: <1397122658-16013-1-git-send-email-cw00.choi@samsung.com>
 <1397122658-16013-5-git-send-email-cw00.choi@samsung.com>
 <20140411014424.GA14934@quad.lixom.net> <53477A19.6070509@samsung.com>
 <006f01cf554b$dbc6a2d0$9353e870$@samsung.com>
Message-ID: <5347966D.7040300@samsung.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Hi Sangbeom,

On 11.04.2014 08:04, Sangbeom Kim wrote:
> Hi,
> On 04/11/2014 2:14 PM, Chanwoo Choi wrote:
>
>>>>   {
>>>> -	exynos_smc(SMC_CMD_CPU1BOOT, cpu, 0, 0);
>>>> +	if (soc_is_exynos4212())
>>>> +		exynos_smc(SMC_CMD_CPU1BOOT, 0, 0, 0);
>>>> +	else
>>>> +		exynos_smc(SMC_CMD_CPU1BOOT, cpu, 0, 0);
>>>
>>> 	/* <explain why you need this special case on 4212> */
>>
>> It's better to ask system lsi person. We don't know it well.
>> I got the guide about secondary boot from system lsi.
>> But, this patch was completely tested.
>
> exynos_smc(SMC_CMD_CPU1BOOT, ...) is cpu hotplug SMC interface.
> Exynos4212 is dual core processor.
> Exynos4212 only have to boot cpu1 on smp boot.
> So, Second parameter of exynos_smc is fixed by 0 which means cpu1.
> It don't need to boot another cpu (ex. cpu2, cpu3 for quad core processor).
> But In case of quad core processor (ex. Exynos4412),
> It need to boot another cpu and specify parameter of booting core.
> As I know, Exynos3250 is dual core.
> So It can be included 1st condition too.

Is the smc API defined to ignore the first argument of SMC_CMD_CPU1BOOT 
command for dual core systems or it is defined as should be zero?

Best regards,
Tomasz