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Date:   Thu, 2 Jun 2022 16:38:19 +0700
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Subject: Re: [Openipmi-developer] [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC
 driver
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To:     minyard@acm.org
Cc:     devicetree@vger.kernel.org, linux-aspeed@lists.ozlabs.org,
        Andrew Jeffery <andrew@aj.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        openbmc@lists.ozlabs.org,
        "Thang Q . Nguyen" <thang@os.amperecomputing.com>,
        Brendan Higgins <brendanhiggins@google.com>,
        linux-kernel@vger.kernel.org,
        Phong Vo <phong@os.amperecomputing.com>,
        Wolfram Sang <wsa@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        openipmi-developer@lists.sourceforge.net,
        Open Source Submission <patches@amperecomputing.com>,
        linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
References: <20220422040803.2524940-1-quan@os.amperecomputing.com>
 <20220422040803.2524940-2-quan@os.amperecomputing.com>
 <20220423015119.GE426325@minyard.net>
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 <20220504120631.GE3767252@minyard.net>
 <ba084735-0781-7ca2-4d04-a70a4115729a@os.amperecomputing.com>
 <20220602003244.GK3767252@minyard.net>
From:   Quan Nguyen <quan@os.amperecomputing.com>
In-Reply-To: <20220602003244.GK3767252@minyard.net>
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On 02/06/2022 07:32, Corey Minyard wrote:
> On Wed, Jun 01, 2022 at 03:23:11PM +0700, Quan Nguyen wrote:
>> On 04/05/2022 19:06, Corey Minyard wrote:
>>> On Wed, May 04, 2022 at 01:45:03PM +0700, Quan Nguyen via Openipmi-developer wrote:
>>>>>
>>>>> I seem to remember mentioning this before, but there is no reason to
>>>>> pack the structures below.
>>>>>
>>>>
>>>> The packed structure is because we want to pick the len directly from user
>>>> space without worry about the padding byte.
>>>>
>>>> As we plan not to use the .h file in next version, I still would like to use
>>>> packed structure internally inside ssif_bmc.c file.
>>>
>>> Packed doesn't matter for the userspace API.  If you look at other
>>> structures in the userspace API, they are not packed, either.  The
>>> compiler will do the right thing on both ends.
>>>
>>>>
>>>>> And second, the following is a userspace API structures, so it needs to
>>>>> be in its own file in include/uapi/linux, along with any supporting
>>>>> things that users will need to use.  And your userspace code should be
>>>>> using that file.
>>>>>
>>>>
>>>> Meantime, I'd like not to use .h as I see there is no demand for sharing the
>>>> data structure between kernel and user space yet. But we may do it in the
>>>> future.
>>>
>>> If you have a userspace API, it needs to be in include/uapi/linux.
>>> You may not be the only user of this code.  In fact, you probably won't
>>> be.  You need to have a .h with the structures in it, you don't want the
>>> same structure in two places if you can help it.
>>>
>>
>> Dear Corey,
>>
>> Is it OK to push the structure definition into the
>> include/uapi/linux/ipmi_bmc.h ?
>>
>> Or should it need to be in separate new header file in uapi/linux ?
> 
> I think a different file, like ipmi_ssif_bmc, to match the file and
> operation.  Unless you need the things in ipmi_bmc.h, which I don't
> think is the case.
> 

Thanks Corey,
Will add ipmi_ssif_bmc as you suggested.

-- Quan