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Subject: Re: [PATCH 6/6] arm64: enable RapidIO menu in Kconfig
From:   Alex Bounine <alex.bou9@gmail.com>
To:     Will Deacon <will.deacon@arm.com>, Alexei Colin <acolin@isi.edu>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Russell King <linux@armlinux.org.uk>,
        John Paul Walters <jwalters@isi.edu>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
References: <20180730225035.28365-1-acolin@isi.edu>
 <20180730225035.28365-7-acolin@isi.edu> <20180731084143.GA4680@arm.com>
 <d09cb4f5-768b-acd8-f9b1-d1d320a93564@gmail.com>
Message-ID: <f2723578-f39d-27ac-b376-0f06905caa67@gmail.com>
Date:   Tue, 31 Jul 2018 16:29:56 -0400
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On 2018-07-31 08:54 AM, Alex Bounine wrote:
> On 2018-07-31 04:41 AM, Will Deacon wrote:
>> On Mon, Jul 30, 2018 at 06:50:34PM -0400, Alexei Colin wrote:
>>> Platforms with a PCI bus will be offered the RapidIO menu since they may
>>> be want support for a RapidIO PCI device. Platforms without a PCI bus
>>> that might include a RapidIO IP block will need to "select HAS_RAPIDIO"
>>> in the platform-/machine-specific "config ARCH_*" Kconfig entry.
>>>
>>> Tested that kernel builds for arm64 with RapidIO subsystem and
>>> switch drivers enabled, also that the modules load successfully
>>> on a custom Aarch64 Qemu model.
>>>
>>> Cc: Andrew Morton <akpm@linux-foundation.org>
>>> Cc: Russell King <linux@armlinux.org.uk>
>>> Cc: John Paul Walters <jwalters@isi.edu>
>>> Cc: linux-arm-kernel@lists.infradead.org
>>> Cc: linux-kernel@vger.kernel.org,
>>> Signed-off-by: Alexei Colin <acolin@isi.edu>
>>> ---
>>>   arch/arm64/Kconfig | 2 ++
>>>   1 file changed, 2 insertions(+)
>>
>> Thanks, this looks much cleaner than before:
>>
>> Acked-by: Will Deacon <will.deacon@arm.com>
>>
>> The only thing I'm not sure about is why we don't just select HAS_RAPIDIO
>> unconditionally in the arm64 Kconfig. Does selecting only that option
>> actually pull in new code to the build?
>>
> HAS_RAPIDIO option is intended for SOCs that have built in SRIO 
> controllers, like TI KeyStoneII or FPGAs. Because RapidIO subsystem core 
> is required during RapidIO port driver initialization, having separate 
> option allows us to control available build options for RapidIO core and 
> port driver (bool vs. tristate) and disable module option if port driver 
> is configured as built-in.

I am thinking about where HAS_RAPIDIO option can be set for arm64 
branch. Having it set globally is too broad. For example we have Xilinx 
Zinq US board with SRIO IP on it. Having it globally in arm64 branch - 
bad. Probably having it set in drivers/soc/... is the best place.

Will, Alexei what do you think?


> 
>> Will
>>
>>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>>> index a8f0c74e6f7f..5e8cf90505ec 100644
>>> --- a/arch/arm64/Kconfig
>>> +++ b/arch/arm64/Kconfig
>>> @@ -308,6 +308,8 @@ config PCI_SYSCALL
>>>   source "drivers/pci/Kconfig"
>>> +source "drivers/rapidio/Kconfig"
>>> +
>>>   endmenu
>>>   menu "Kernel Features"
>>> -- 
>>> 2.18.0
>>>