linux-kernel - Re: [PATCHv4 3/7] ARM: EXYNOS: Support secondary CPU boot of Exynos3250

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Date:	Fri, 25 Apr 2014 11:24:28 +0530
From:	Tushar Behera <tushar.behera@...aro.org>
To:	Chanwoo Choi <cw00.choi@...sung.com>
CC:	kgene.kim@...sung.com, t.figa@...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, sachin.kamat@...aro.org,
	linux-samsung-soc@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org
Subject: Re: [PATCHv4 3/7] ARM: EXYNOS: Support secondary CPU boot of Exynos3250

On 04/25/2014 11:13 AM, Chanwoo Choi wrote:
> Hi,
> 
> On 04/25/2014 01:30 PM, Tushar Behera wrote:
>> On 04/25/2014 06:46 AM, Chanwoo Choi wrote:
>>> This patch fix the offset of CPU boot address and don't need to send smc call
>>> of SMC_CMD_CPU1BOOT command for secondary CPU boot because Exynos3250 removes
>>> WFE in secure mode.
>>>
>>> Signed-off-by: Chanwoo Choi <cw00.choi@...sung.com>
>>> Acked-by: Kyungmin Park <kyungmin.park@...sung.com>
>>> ---
>>>  arch/arm/mach-exynos/firmware.c | 10 ++++++++--
>>>  1 file changed, 8 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/arch/arm/mach-exynos/firmware.c b/arch/arm/mach-exynos/firmware.c
>>> index aa01c42..386d01d 100644
>>> --- a/arch/arm/mach-exynos/firmware.c
>>> +++ b/arch/arm/mach-exynos/firmware.c
>>> @@ -31,11 +31,17 @@ static int exynos_do_idle(void)
>>>  static int exynos_cpu_boot(int cpu)
>>>  {
>>>  	/*
>>> +	 * Exynos3250 doesn't need to send smc command for secondary CPU boot
>>> +	 * because Exynos3250 removes WFE in secure mode.
>>> +	 */
>>> +	if (soc_is_exynos3250())
>>> +		return 0;
>>> +	/*
>>>  	 * The second parameter of SMC_CMD_CPU1BOOT command means CPU id.
>>>  	 * But, Exynos4212 has only one secondary CPU so second parameter
>>>  	 * isn't used for informing secure firmware about CPU id.
>>>  	 */
>>> -	if (soc_is_exynos4212())
>>> +	else if (soc_is_exynos4212())
>>
>> This changes is not required.
> 
> Do you mean it as following?
> 
> 	if (soc_is_exynos3250())
> 		return 0
> 
> 	if (soc_is_exynos4212())
> 		cpu = 0;
> 

Yes, logically the flow would be same and code would be more readable.

>>
>>>  		cpu = 0;
>>>  
>>>  	exynos_smc(SMC_CMD_CPU1BOOT, cpu, 0, 0);
>>> @@ -46,7 +52,7 @@ static int exynos_set_cpu_boot_addr(int cpu, unsigned long boot_addr)
>>>  {
>>>  	void __iomem *boot_reg = S5P_VA_SYSRAM_NS + 0x1c;
>>>  
>>> -	if (!soc_is_exynos4212())
>>> +	if (!soc_is_exynos4212() && !soc_is_exynos3250())
>>>  		boot_reg += 4*cpu;
>>>  
>>>  	__raw_writel(boot_addr, boot_reg);
>>>
>>
>>
> 


-- 
Tushar Behera
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