Re: [PATCH net-next v4 2/2] net: phy: broadcom: add 1000Base-X support for BCM54616S

From: Tao Ren <taoren@fb.com>
To: Heiner Kallweit <hkallweit1@gmail.com>,
	Andrew Lunn <andrew@lunn.ch>,
	Florian Fainelli <f.fainelli@gmail.com>,
	"David S . Miller" <davem@davemloft.net>,
	Arun Parameswaran <arun.parameswaran@broadcom.com>,
	Justin Chen <justinpopo6@gmail.com>,
	Vladimir Oltean <olteanv@gmail.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"openbmc@lists.ozlabs.org" <openbmc@lists.ozlabs.org>
Subject: Re: [PATCH net-next v4 2/2] net: phy: broadcom: add 1000Base-X support for BCM54616S
Date: Thu, 8 Aug 2019 04:24:30 +0000	[thread overview]
Message-ID: <a827c44c-3946-8f6f-e515-b476fd375cf6@fb.com> (raw)
In-Reply-To: <cfd6e14e-a447-aedb-5bd6-bf65b4b6f98a@gmail.com>

Hi Heiner,

On 8/7/19 12:18 PM, Heiner Kallweit wrote:
> On 06.08.2019 23:42, Tao Ren wrote:
>> Hi Andrew / Heiner / Vladimir,
>>
>> On 8/6/19 2:09 PM, Tao Ren wrote:
>>> The BCM54616S PHY cannot work properly in RGMII->1000Base-KX mode (for
>>> example, on Facebook CMM BMC platform), mainly because genphy functions
>>> are designed for copper links, and 1000Base-X (clause 37) auto negotiation
>>> needs to be handled differently.
>>>
>>> This patch enables 1000Base-X support for BCM54616S by customizing 3
>>> driver callbacks:
>>>
>>>   - probe: probe callback detects PHY's operation mode based on
>>>     INTERF_SEL[1:0] pins and 1000X/100FX selection bit in SerDES 100-FX
>>>     Control register.
>>>
>>>   - config_aneg: bcm54616s_config_aneg_1000bx function is added for auto
>>>     negotiation in 1000Base-X mode.
>>>
>>>   - read_status: BCM54616S and BCM5482 PHY share the same read_status
>>>     callback which manually set link speed and duplex mode in 1000Base-X
>>>     mode.
>>>
>>> Signed-off-by: Tao Ren <taoren@fb.com>
>>
>> I customized config_aneg function for BCM54616S 1000Base-X mode and link-down issue is also fixed: the patch is tested on Facebook CMM and Minipack BMC and everything looks normal. Please kindly review when you have bandwidth and let me know if you have further suggestions.
>>
>> BTW, I would be happy to help if we decide to add a set of genphy functions for clause 37, although that may mean I need more help/guidance from you :-)
> 
> You want to have standard clause 37 aneg and this should be generic in phylib.
> I hacked together a first version that is compile-tested only:
> https://urldefense.proofpoint.com/v2/url?u=https-3A__patchwork.ozlabs.org_patch_1143631_&d=DwICaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=iYElT7HC77pRZ3byVvW8ng&m=ZJArOJvHqNkqvs1x8l9HjfxjCN8e5xJpPz2YViBuKRA&s=EskpfBQtu9IBVeb96dv-sz76xIz4tJK5-lD4-qdIyWI&e= 
> It supports fixed mode too.
> 
> It doesn't support half duplex mode because phylib doesn't know 1000BaseX HD yet.
> Not sure whether half duplex mode is used at all in reality.
> 
> You could test the new core functions in your own config_aneg and read_status
> callback implementations.

Thank you very much for the help! I'm planning to add these functions but I haven't started yet because I'm still going through clause 37 :-)

Let me apply your patch and run some test on my platform. Will share you results tomorrow.

Cheers,

Tao