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Subject: Re: [PATCH] arch64: export __flush_dcache_area
To:     Catalin Marinas <catalin.marinas@arm.com>
Cc:     linux-kernel@vger.kernel.org, kernel-team@android.com,
        Will Deacon <will.deacon@arm.com>,
        linux-arm-kernel@lists.infradead.org
References: <20190517200012.136519-1-salyzyn@android.com>
 <20190517215303.3daebi7o66we2cjh@mbp>
From:   Mark Salyzyn <salyzyn@android.com>
Message-ID: <735fc46d-69a4-6b65-f0f7-a09c2be438a8@android.com>
Date:   Mon, 20 May 2019 07:29:46 -0700
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On 05/17/2019 02:53 PM, Catalin Marinas wrote:
> On Fri, May 17, 2019 at 12:59:56PM -0700, Mark Salyzyn wrote:
>> Some (out of tree modular) drivers feel a need to ensure
>> data is flushed to the DDR before continuing flow.
>>
>> Signed-off-by: Mark Salyzyn <salyzyn@android.com>
>> Cc: linux-kernel@vger.kernel.org
>> Cc: kernel-team@android.com
>> ---
>>   arch/arm64/mm/cache.S | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
>> index a194fd0e837f..70d7cb5c0bd2 100644
>> --- a/arch/arm64/mm/cache.S
>> +++ b/arch/arm64/mm/cache.S
>> @@ -120,6 +120,7 @@ ENTRY(__flush_dcache_area)
>>   	dcache_by_line_op civac, sy, x0, x1, x2, x3
>>   	ret
>>   ENDPIPROC(__flush_dcache_area)
>> +EXPORT_SYMBOL_GPL(__flush_dcache_area)
>>   
>>   /*
>>    *	__clean_dcache_area_pou(kaddr, size)
> NAK. Such drivers are doing something wrong, there is a dedicated
> in-kernel API for that handles kernel maintenance (hint: DMA).
Thanks!

-- Mark