• Oleksij Rempel's avatar
    ethtool: provide UAPI for PHY master/slave configuration. · bdbdac76
    Oleksij Rempel authored
    This UAPI is needed for BroadR-Reach 100BASE-T1 devices. Due to lack of
    auto-negotiation support, we needed to be able to configure the
    MASTER-SLAVE role of the port manually or from an application in user
    space.
    
    The same UAPI can be used for 1000BASE-T or MultiGBASE-T devices to
    force MASTER or SLAVE role. See IEEE 802.3-2018:
    22.2.4.3.7 MASTER-SLAVE control register (Register 9)
    22.2.4.3.8 MASTER-SLAVE status register (Register 10)
    40.5.2 MASTER-SLAVE configuration resolution
    45.2.1.185.1 MASTER-SLAVE config value (1.2100.14)
    45.2.7.10 MultiGBASE-T AN control 1 register (Register 7.32)
    
    The MASTER-SLAVE role affects the clock configuration:
    
    -------------------------------------------------------------------------------
    When the  PHY is configured as MASTER, the PMA Transmit function shall
    source TX_TCLK from a local clock source. When configured as SLAVE, the
    PMA Transmit function shall source TX_TCLK from the clock recovered from
    data stream provided by MASTER.
    
    iMX6Q                     KSZ9031                XXX
    ------\                /-----------\        /------------\
          |                |           |        |            |
     MAC  |<----RGMII----->| PHY Slave |<------>| PHY Master |
          |<--- 125 MHz ---+-<------/  |        | \          |
    ------/                \-----------/        \------------/
                                                   ^
                                                    \-TX_TCLK
    
    -------------------------------------------------------------------------------
    
    Since some clock or link related issues are only reproducible in a
    specific MASTER-SLAVE-role, MAC and PHY configuration, it is beneficial
    to provide generic (not 100BASE-T1 specific) interface to the user space
    for configuration flexibility and trouble shooting.
    Signed-off-by: default avatarOleksij Rempel <o.rempel@pengutronix.de>
    Reviewed-by: default avatarAndrew Lunn <andrew@lunn.ch>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    bdbdac76
phy.c 30.4 KB