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

[Tao Ren <taoren@fb.com>]

On 8/9/19 2:59 PM, Heiner Kallweit wrote:
> On 09.08.2019 23:13, Tao Ren wrote:
>> On 8/9/19 1:54 PM, Tao Ren wrote:
>>> 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@fb.com>
>>>>> ---
>>>>>  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.
>>
>> I can prepare a patch for 100Base-FX based on my understanding of bcm54616s datasheet, but the patch would be just compile-tested 
>>
> Support for 1000Base-X should be sufficient. Best mention the missing support for
> 100Base-FX in the commit message and at a suited place in the driver code.

Make sense. Will do it soon.


Thanks,

Tao