linux-kernel - Re: [PATCHv2 5/8] ARM: EXYNOS: Support secondary CPU boot of Exynos3250

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Message-id: <534F8B11.8090808@samsung.com>
Date:	Thu, 17 Apr 2014 17:04:33 +0900
From:	Chanwoo Choi <cw00.choi@...sung.com>
To:	Tomasz Figa <t.figa@...sung.com>
Cc:	linux-kernel@...r.kernel.org, linux@....linux.org.uk,
	ben-linux@...ff.org, kgene.kim@...sung.com,
	thomas.abraham@...aro.org, kyungmin.park@...sung.com,
	sw0312.kim@...sung.com, hyunhee.kim@...sung.com,
	yj44.cho@...sung.com, chanho61.park@...sung.com, arnd@...db.de,
	olof@...om.net, marc.zyngier@....com,
	linux-samsung-soc@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org
Subject: Re: [PATCHv2 5/8] ARM: EXYNOS: Support secondary CPU boot of Exynos3250

Hi Tomasz,

On 04/16/2014 11:28 PM, Tomasz Figa wrote:
> Hi Chanwoo,
> 
> On 15.04.2014 03:59, Chanwoo Choi wrote:
>> This patch fix the offset of CPU boot address and don't operate smc call
>> of SMC_CMD_CPU1BOOT command for Exynos3250.
>>
>> Signed-off-by: Chanwoo Choi <cw00.choi@...sung.com>
>> Acked-by: Kyungmin Park <kyungmin.park@...sung.com>
>> ---
>>   arch/arm/mach-exynos/firmware.c | 7 +++++--
>>   1 file changed, 5 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm/mach-exynos/firmware.c b/arch/arm/mach-exynos/firmware.c
>> index aa01c42..6205d4f 100644
>> --- a/arch/arm/mach-exynos/firmware.c
>> +++ b/arch/arm/mach-exynos/firmware.c
>> @@ -30,13 +30,16 @@ static int exynos_do_idle(void)
>>
>>   static int exynos_cpu_boot(int cpu)
>>   {
>> +    if (soc_is_exynos3250()) {
>> +        return 0;
> 
> This is strange. How the firmware knows when to boot the CPU then, if CPU1BOOT command is not called?

As I knew, Exynos3250 doesn't need smc for secondary boot
because WFE in secure mode for Exynos3250 is removed.
So, Exynos3250 doesn't need to send IPI_WAKEUP after call_firmware_op(cpu_boot, ...).

Best Regards,
Chanwoo Choi

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