Re: [PATCH net-next v6 3/3] net: phy: broadcom: add 1000Base-X support for BCM54616S

[Tao Ren]

Hi Heiner,

On 8/9/19 1:21 PM, Heiner Kallweit wrote:
> On 09.08.2019 07:44, 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: calls genphy_c37_config_aneg when the PHY is running in
>>     1000Base-X mode; otherwise, genphy_config_aneg will be called.
>>
>>   - read_status: calls genphy_c37_read_status when the PHY is running in
>>     1000Base-X mode; otherwise, genphy_read_status will be called.
>>
>> Signed-off-by: Tao Ren <taoren@xxxxxx>
>> ---
>>  Changes in v6:
>>   - nothing changed.
>>  Changes in v5:
>>   - include Heiner's patch "net: phy: add support for clause 37
>>     auto-negotiation" into the series.
>>   - use genphy_c37_config_aneg and genphy_c37_read_status in BCM54616S
>>     PHY driver's callback when the PHY is running in 1000Base-X mode.
>>  Changes in v4:
>>   - add bcm54616s_config_aneg_1000bx() to deal with auto negotiation in
>>     1000Base-X mode.
>>  Changes in v3:
>>   - rename bcm5482_read_status to bcm54xx_read_status so the callback can
>>     be shared by BCM5482 and BCM54616S.
>>  Changes in v2:
>>   - Auto-detect PHY operation mode instead of passing DT node.
>>   - move PHY mode auto-detect logic from config_init to probe callback.
>>   - only set speed (not including duplex) in read_status callback.
>>   - update patch description with more background to avoid confusion.
>>   - patch #1 in the series ("net: phy: broadcom: set features explicitly
>>     for BCM54616") is dropped: the fix should go to get_features callback
>>     which may potentially depend on this patch.
>>
>>  drivers/net/phy/broadcom.c | 54 +++++++++++++++++++++++++++++++++++---
>>  include/linux/brcmphy.h    | 10 +++++--
>>  2 files changed, 58 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/net/phy/broadcom.c b/drivers/net/phy/broadcom.c
>> index 937d0059e8ac..fbd76a31c142 100644
>> --- a/drivers/net/phy/broadcom.c
>> +++ b/drivers/net/phy/broadcom.c
>> @@ -383,9 +383,9 @@ static int bcm5482_config_init(struct phy_device *phydev)
>>  		/*
>>  		 * Select 1000BASE-X register set (primary SerDes)
>>  		 */
>> -		reg = bcm_phy_read_shadow(phydev, BCM5482_SHD_MODE);
>> -		bcm_phy_write_shadow(phydev, BCM5482_SHD_MODE,
>> -				     reg | BCM5482_SHD_MODE_1000BX);
>> +		reg = bcm_phy_read_shadow(phydev, BCM54XX_SHD_MODE);
>> +		bcm_phy_write_shadow(phydev, BCM54XX_SHD_MODE,
>> +				     reg | BCM54XX_SHD_MODE_1000BX);
>>  
>>  		/*
>>  		 * LED1=ACTIVITYLED, LED3=LINKSPD[2]
>> @@ -451,12 +451,44 @@ static int bcm5481_config_aneg(struct phy_device *phydev)
>>  	return ret;
>>  }
>>  
>> +static int bcm54616s_probe(struct phy_device *phydev)
>> +{
>> +	int val, intf_sel;
>> +
>> +	val = bcm_phy_read_shadow(phydev, BCM54XX_SHD_MODE);
>> +	if (val < 0)
>> +		return val;
>> +
>> +	/* The PHY is strapped in RGMII to fiber mode when INTERF_SEL[1:0]
>> +	 * is 01b.
>> +	 */
>> +	intf_sel = (val & BCM54XX_SHD_INTF_SEL_MASK) >> 1;
>> +	if (intf_sel == 1) {
>> +		val = bcm_phy_read_shadow(phydev, BCM54616S_SHD_100FX_CTRL);
>> +		if (val < 0)
>> +			return val;
>> +
>> +		/* Bit 0 of the SerDes 100-FX Control register, when set
>> +		 * to 1, sets the MII/RGMII -> 100BASE-FX configuration.
>> +		 * When this bit is set to 0, it sets the GMII/RGMII ->
>> +		 * 1000BASE-X configuration.
>> +		 */
>> +		if (!(val & BCM54616S_100FX_MODE))
>> +			phydev->dev_flags |= PHY_BCM_FLAGS_MODE_1000BX;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>>  static int bcm54616s_config_aneg(struct phy_device *phydev)
>>  {
>>  	int ret;
>>  
>>  	/* Aneg firsly. */
>> -	ret = genphy_config_aneg(phydev);
>> +	if (phydev->dev_flags & PHY_BCM_FLAGS_MODE_1000BX)
>> +		ret = genphy_c37_config_aneg(phydev);
>> +	else
>> +		ret = genphy_config_aneg(phydev);
>>  
> 
> I'm just wondering whether it needs to be considered that 100base-FX
> doesn't support auto-negotiation. I suppose BMSR reports aneg as
> supported, therefore phylib will use aneg per default.
> Not sure who could set 100Base-FX mode when, but maybe at that place
> also phydev->autoneg needs to be cleared. Did you test 100Base-FX mode?

I'm doubting if 100Base-FX works. Besides auto-negotiation, 100Base-FX Control/Status registers are defined in shadow register instead of MII_BMCR and MII_BMSR.

Unfortunately I don't have environment to test 100Base-FX and that's why I only make changes when the PHY is working in 1000X mode.


Thanks,

Tao