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Date:   Tue, 13 Oct 2020 08:15:15 +0800
From:   Jiaxun Yang <jiaxun.yang@flygoat.com>
To:     Tiezhu Yang <yangtiezhu@loongson.cn>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>
CC:     Jonathan Corbet <corbet@lwn.net>, Huacai Chen <chenhc@lemote.com>,
        linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-doc@vger.kernel.org, Xuefeng Li <lixuefeng@loongson.cn>
Subject: Re: [PATCH v2 3/4 RESEND] MIPS: Loongson64: Add /proc/boardinfo
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=E4=BA=8E 2020=E5=B9=B410=E6=9C=8812=E6=97=A5 GMT+08:00 =E4=B8=8B=E5=8D=88=
8:02:25, Tiezhu Yang <yangtiezhu@loongson=2Ecn> =E5=86=99=E5=88=B0:
>On 10/12/2020 06:38 PM, Thomas Bogendoerfer wrote:
>> On Sun, Oct 11, 2020 at 07:47:53AM +0800, Tiezhu Yang wrote:
>>> Add /proc/boardinfo to get mainboard and BIOS info easily on the Loong=
son
>>> platform, this is useful to point out the current used mainboard type =
and
>>> BIOS version when there exists problems related with hardware or firmw=
are=2E
>>>
>>> E=2Eg=2E with this patch:
>>>
>>> [loongson@linux ~]$ cat /proc/boardinfo
>>> Board Info
>>> Manufacturer            : LEMOTE
>>> Board Name              : LEMOTE-LS3A4000-7A1000-1w-V01-pc
>>> Family                  : LOONGSON3
>>>
>>> BIOS Info
>>> Vendor                  : Kunlun
>>> Version                 : Kunlun-A1901-V4=2E1=2E3-20200414093938
>>> ROM Size                : 4 KB
>>> Release Date            : 2020-04-14
>> Why does Loongson64 need this extra file no other architecture or MIPS
>> platform need ? Do others provide this information via a different meth=
od ?
>> If yes, why can't Loongson64 do the same ?
>
>Hi Thomas,
>
>This is related with the implementation of firmware=2E
>
>Using dmidecode command can get the similar info if there exists SMBIOS
>in firmware, but the fact is there is no SMBIOS on some machines, we can
>see nothing when execute dmidecode, like this:
>
>[root@linux loongson]# dmidecode
># dmidecode 2=2E12
># No SMBIOS nor DMI entry point found, sorry=2E
>
>The following three structures are already defined in the interface
>specification about firmware and kernel on the Loongson platform,
>this is common requirement and specific for Loongson64, so add a
>new boardinfo=2Ec file in arch/mips/loongson64=2E
>
>arch/mips/include/asm/mach-loongson64/boot_param=2Eh
>struct interface_info {
>     u16 vers; /* version of the specificition */
>     u16 size;
>     u8  flag;
>     char description[64];
>} __packed;
>
>struct board_devices {
>     char name[64];    /* hold the device name */
>     u32 num_resources; /* number of device_resource */
>     /* for each device's resource */
>     struct resource_loongson resource[MAX_RESOURCE_NUMBER];
>     /* arch specific additions */
>     struct archdev_data archdata;
>};
>
>struct loongson_special_attribute {
>     u16 vers;     /* version of this special */
>     char special_name[64]; /* special_atribute_name */
>     u32 loongson_special_type; /* type of special device */
>     /* for each device's resource */
>     struct resource_loongson resource[MAX_RESOURCE_NUMBER];
>};

Hi Tiezhu,

Through I don't think touching top level of proc would be a good idea=2E I=
t's all about API consistency=2E

If you intend to provide user an interface then I guess /sys/firmware/lefi
like what DMI did or somewhere less critical is better=2E

There is no guarantee that Loongson64 device would come with LEFI,
although it's mandatory for now=2E

Thanks=2E

- Jiaxun

>
>Thanks,
>Tiezhu
>
>>
>> Thomas=2E
>>