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Date:   Fri, 31 Mar 2023 14:55:56 +0530
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Subject: Re: [PATCH net-next 2/2] net: ethernet: ti: am65-cpsw: Enable USXGMII
 mode for J784S4 CPSW9G
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To:     "Russell King (Oracle)" <linux@armlinux.org.uk>
References: <20230331065110.604516-1-s-vadapalli@ti.com>
 <20230331065110.604516-3-s-vadapalli@ti.com>
 <ZCaSXQFZ/e/JIDEj@shell.armlinux.org.uk>
 <54c3964b-5dd8-c55e-08db-61df4a07797c@ti.com>
 <ZCaYve8wYl15YRxh@shell.armlinux.org.uk>
From:   Siddharth Vadapalli <s-vadapalli@ti.com>
In-Reply-To: <ZCaYve8wYl15YRxh@shell.armlinux.org.uk>
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Russell,

On 31/03/23 13:54, Russell King (Oracle) wrote:
> On Fri, Mar 31, 2023 at 01:35:10PM +0530, Siddharth Vadapalli wrote:
>> Hello Russell,
>>
>> Thank you for reviewing the patch.
>>
>> On 31/03/23 13:27, Russell King (Oracle) wrote:
>>> On Fri, Mar 31, 2023 at 12:21:10PM +0530, Siddharth Vadapalli wrote:
>>>> TI's J784S4 SoC supports USXGMII mode. Add USXGMII mode to the
>>>> extra_modes member of the J784S4 SoC data. Additionally, configure the
>>>> MAC Control register for supporting USXGMII mode. Also, for USXGMII
>>>> mode, include MAC_5000FD in the "mac_capabilities" member of struct
>>>> "phylink_config".
>>>
>>> I don't think TI "get" phylink at all...
>>>
>>>> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
>>>> index 4b4d06199b45..ab33e6fe5b1a 100644
>>>> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
>>>> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
>>>> @@ -1555,6 +1555,8 @@ static void am65_cpsw_nuss_mac_link_up(struct phylink_config *config, struct phy
>>>>  		mac_control |= CPSW_SL_CTL_GIG;
>>>>  	if (interface == PHY_INTERFACE_MODE_SGMII)
>>>>  		mac_control |= CPSW_SL_CTL_EXT_EN;
>>>> +	if (interface == PHY_INTERFACE_MODE_USXGMII)
>>>> +		mac_control |= CPSW_SL_CTL_XGIG | CPSW_SL_CTL_XGMII_EN;
>>>
>>> The configuration of the interface mode should *not* happen in
>>> mac_link_up(), but should happen in e.g. mac_config().
>>
>> I will move all the interface mode associated configurations to mac_config() in
>> the v2 series.
> 
> Looking at the whole of mac_link_up(), could you please describe what
> effect these bits are having:
> 
> 	CPSW_SL_CTL_GIG
> 	CPSW_SL_CTL_EXT_EN
> 	CPSW_SL_CTL_IFCTL_A

CPSW_SL_CTL_GIG corresponds to enabling Gigabit mode (full duplex only).
CPSW_SL_CTL_EXT_EN when set enables in-band mode of operation and when cleared
enables forced mode of operation.
CPSW_SL_CTL_IFCTL_A is used to set the RMII link speed (0=10 mbps, 1=100 mbps).

Regards,
Siddharth.