Re: [PATCH net-next v5 2/8] net: phy: Add phydev->enable_tx_lpi to simplify adjust link callbacks

[Heiner Kallweit <hkallweit1@gmail.com>]

On 23.02.2024 06:36, Wei Fang wrote:
>> -----Original Message-----
>> From: Oleksij Rempel <o.rempel@pengutronix.de>
>> Sent: 2024年2月21日 14:21
>> To: Wei Fang <wei.fang@nxp.com>; David S. Miller <davem@davemloft.net>;
>> Eric Dumazet <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>;
>> Paolo Abeni <pabeni@redhat.com>; Andrew Lunn <andrew@lunn.ch>;
>> Heiner Kallweit <hkallweit1@gmail.com>; Russell King
>> <linux@armlinux.org.uk>
>> Cc: Florian Fainelli <florian.fainelli@broadcom.com>; Oleksij Rempel
>> <o.rempel@pengutronix.de>; kernel@pengutronix.de;
>> linux-kernel@vger.kernel.org; netdev@vger.kernel.org; Shenwei Wang
>> <shenwei.wang@nxp.com>; Clark Wang <xiaoning.wang@nxp.com>;
>> dl-linux-imx <linux-imx@nxp.com>
>> Subject: [PATCH net-next v5 2/8] net: phy: Add phydev->enable_tx_lpi to
>> simplify adjust link callbacks
>>
>> From: Andrew Lunn <andrew@lunn.ch>
>>
>> MAC drivers which support EEE need to know the results of the EEE auto-neg
>> in order to program the hardware to perform EEE or not.  The oddly named
>> phy_init_eee() can be used to determine this, it returns 0 if EEE should be
>> used, or a negative error code, e.g. -EOPPROTONOTSUPPORT if the PHY does
>> not support EEE or negotiate resulted in it not being used.
>>
>> However, many MAC drivers get this wrong. Add phydev->enable_tx_lpi
>> which indicates the result of the autoneg for EEE, including if EEE is
>> administratively disabled with ethtool. The MAC driver can then access this in
>> the same way as link speed and duplex in the adjust link callback. If
>> enable_tx_lpi is true, the MAC should send low power indications and does
>> not need to consider anything else with respect to EEE.
>>
>> Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
>> Signed-off-by: Andrew Lunn <andrew@lunn.ch>
>> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
>> ---
>> v2 Check for errors from genphy_c45_eee_is_active
>> v5: Rename to enable_tx_lpi to fit better with phylink changes
>> ---
>>  drivers/net/phy/phy.c | 7 +++++++
>>  include/linux/phy.h   | 2 ++
>>  2 files changed, 9 insertions(+)
>>
>> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c index
>> 14224e06d69f..a54b1daf5d5f 100644
>> --- a/drivers/net/phy/phy.c
>> +++ b/drivers/net/phy/phy.c
>> @@ -983,9 +983,16 @@ static int phy_check_link_status(struct phy_device
>> *phydev)
>>  	if (phydev->link && phydev->state != PHY_RUNNING) {
>>  		phy_check_downshift(phydev);
>>  		phydev->state = PHY_RUNNING;
>> +		err = genphy_c45_eee_is_active(phydev,
>> +					       NULL, NULL, NULL);
>> +		if (err < 0)
>> +			phydev->enable_tx_lpi = false;
>> +		else
>> +			phydev->enable_tx_lpi = err;
> 
> phydev->enable_tx_lpi = !!err; Is this better?
> 
I don't think so. Effectively err is a bool value, and it's implicitly
converted.

>>  		phy_link_up(phydev);
>>  	} else if (!phydev->link && phydev->state != PHY_NOLINK) {
>>  		phydev->state = PHY_NOLINK;
>> +		phydev->enable_tx_lpi = false;
>>  		phy_link_down(phydev);
>>  	}
>>
>> diff --git a/include/linux/phy.h b/include/linux/phy.h index
>> e3ab2c347a59..a880f6d7170e 100644
>> --- a/include/linux/phy.h
>> +++ b/include/linux/phy.h
>> @@ -594,6 +594,7 @@ struct macsec_ops;
>>   * @supported_eee: supported PHY EEE linkmodes
>>   * @advertising_eee: Currently advertised EEE linkmodes
>>   * @eee_enabled: Flag indicating whether the EEE feature is enabled
>> + * @enable_tx_lpi: When True, MAC should transmit LPI to PHY
>>   * @lp_advertising: Current link partner advertised linkmodes
>>   * @host_interfaces: PHY interface modes supported by host
>>   * @eee_broken_modes: Energy efficient ethernet modes which should be
>> prohibited @@ -713,6 +714,7 @@ struct phy_device {
>>
>>  	/* Energy efficient ethernet modes which should be prohibited */
>>  	u32 eee_broken_modes;
>> +	bool enable_tx_lpi;
>>
>>  #ifdef CONFIG_LED_TRIGGER_PHY
>>  	struct phy_led_trigger *phy_led_triggers;
>> --
>> 2.39.2
>