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From: Joel Stanley <joel@jms.id.au>
Date: Tue, 16 Jan 2018 17:06:57 -0600
Message-ID: <CACPK8XfmrtJkUcFXNRDh7t3EDaETU1R=RawkErgduPG--CEVEg@mail.gmail.com>
Subject: Re: [PATCH arm/aspeed/ast2500 v1] ipmi: add an Aspeed KCS IPMI BMC driver
To: Corey Minyard <minyard@acm.org>, Ed Tanous <ed.tanous@intel.com>,
        james.mihm@intel.com, OpenBMC Maillist <openbmc@lists.ozlabs.org>,
        tomer.maimon@nuvoton.com
Cc: Haiyue Wang <haiyue.wang@linux.intel.com>,
        openipmi-developer@lists.sourceforge.net,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        andriy.shevchenko@intel.com
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Sender: linux-kernel-owner@vger.kernel.org

On Tue, Jan 16, 2018 at 2:59 PM, Corey Minyard <minyard@acm.org> wrote:
> On 01/16/2018 05:43 AM, Haiyue Wang wrote:
>>
>> The KCS (Keyboard Controller Style) interface is used to perform in-band
>> IPMI communication between a server host and its BMC (BaseBoard Management
>> Controllers).
>>
>> This driver exposes the KCS interface on ASpeed SOCs (AST2400 and AST2500)
>> as a character device. Such SOCs are commonly used as BMCs and this driver
>> implements the BMC side of the KCS interface.
>
>
> I thought we were going to unify the BMC ioctl interface?  My preference
> would be to
> create a file named include/uapi/linux/ipmi-bmc.h and add the following:
>
> #define __IPMI_BMC_IOCTL_MAGIC    0xb1
> #define IPMI_BMC_IOCTL_SMS_SET_ATN    _IO(__IPMI_BMC_IOCTL_MAGIC, 0x00)
>
> to make it the same as BT.  Then in bt-bmc.h, set BT_BMC_IOCTL_SMS_ATN to
> IPMI_BMC_IOCTL_SMS_SET_ATN.  Then add the KCS ioctls in ipmi-bmc.h and
> use that.  That way we stay backward compatible but we are unified.
>
> Since more KCS interfaces may come around, can you make the name more
> specific?  (I made this same error on bt-bmc,c, it should probably be
> renamed.)

Yes, we had a group of openbmc people get together recently and spoke
about this. Unfortunately Haiyue wasn't there (but other Intel BMC
people were).

We've got code coming from another BMC vendor who will use the same
userspace API. The intention is to unify ASPEED's KCS and BT, along
with Nuvoton's KCS and BT, as you outlined above.

Cheers,

Joel