On 9/17/2024 2:31 AM, Russell King (Oracle) wrote:
> On Fri, Sep 13, 2024 at 06:35:17PM +0200, Andrew Lunn wrote:
>> On Fri, Sep 13, 2024 at 09:12:13AM -0700, Abhishek Chauhan (ABC) wrote:
>>> On 9/13/2024 1:01 AM, Maxime Chevallier wrote:
>>>> Hi,
>>>>
>>>> On Thu, 12 Sep 2024 18:16:35 -0700
>>>> Abhishek Chauhan <quic_abchauha@xxxxxxxxxxx> wrote:
>>>>
>>>>> Recently we observed that aquantia AQR115c always comes up in
>>>>> 100Mbps mode. AQR115c aquantia chip supports max speed up to
>>>>> 2.5Gbps. Today the AQR115c configuration is done through
>>>>> aqr113c_config_init which internally calls aqr107_config_init.
>>>>> aqr113c and aqr107 are both capable of 10Gbps. Whereas AQR115c
>>>>> supprts max speed of 2.5Gbps only.
>>>>>
>>>>> Fixes: 0ebc581f8a4b ("net: phy: aquantia: add support for aqr115c")
>>>>> Signed-off-by: Abhishek Chauhan <quic_abchauha@xxxxxxxxxxx>
>>>>> ---
>>>>> drivers/net/phy/aquantia/aquantia_main.c | 7 +++++++
>>>>> 1 file changed, 7 insertions(+)
>>>>>
>>>>> diff --git a/drivers/net/phy/aquantia/aquantia_main.c b/drivers/net/phy/aquantia/aquantia_main.c
>>>>> index e982e9ce44a5..9afc041dbb64 100644
>>>>> --- a/drivers/net/phy/aquantia/aquantia_main.c
>>>>> +++ b/drivers/net/phy/aquantia/aquantia_main.c
>>>>> @@ -499,6 +499,12 @@ static int aqr107_config_init(struct phy_device *phydev)
>>>>> if (!ret)
>>>>> aqr107_chip_info(phydev);
>>>>>
>>>>> + /* AQR115c supports speed up to 2.5Gbps */
>>>>> + if (phydev->interface == PHY_INTERFACE_MODE_2500BASEX) {
>>>>> + phy_set_max_speed(phydev, SPEED_2500);
>>>>> + phydev->autoneg = AUTONEG_ENABLE;
>>>>> + }
>>>>> +
>>>>
>>>> If I get your commit log right, the code above will also apply for
>>>> ASQR107, AQR113 and so on, don't you risk breaking these PHYs if they
>>>> are in 2500BASEX mode at boot?
>>>>
>>>
>>> I was thinking of the same. That this might break something here for other Phy chip.
>>> As every phy shares the same config init. Hence the reason for RFC.
>>>
>>>> Besides that, if the PHY switches between SGMII and 2500BASEX
>>>> dynamically depending on the link speed, it could be that it's
>>>> configured by default in SGMII, hence this check will be missed.
>>>>
>>>>
>>> I think the better way is to have AQR115c its own config_init which sets
>>> the max speed to 2.5Gbps and then call aqr113c_config_init .
>>
>> phy_set_max_speed(phydev, SPEED_2500) is something a MAC does, not a
>> PHY. It is a way for the MAC to say is supports less than the PHY. I
>> would say the current aqcs109_config_init() is doing this wrong.
>
> Agreed on two points:
>
> 1) phy_set_max_speed() is documented as a function that the MAC will
> call.
>
> 2) calling phy_set_max_speed() in .config_init() is way too late for
> phylink. .config_init() is called from phy_init_hw(), which happens
> after the PHY has been attached. However, phylink needs to know what
> the PHY supports _before_ that, especially for any PHY that is on a
> SFP, so it can determine what interface to use for the PHY.
>
> So, as Andrew says, the current aqcs109_config_init(), and it seems
> aqr111_config_init() are both broken.
>
> The PHY driver needs to indicate to phylib what is supported by the
> PHY no later than the .get_features() method.
>
Noted!. Makes sense. thanks for your review, Russell.
We are in the process of figuring out what the phy chip is reporting as
its features. Once done i will raise a clean patch for upstream review.
> Thanks.
>
