On 13.01.2022 10:56, Mohammad Athari Bin Ismail wrote:
> Existing genphy_loopback() is not applicable for Marvell PHY. Besides
> configuring bit-6 and bit-13 in Page 0 Register 0 (Copper Control
> Register), it is also required to configure same bits in Page 2
> Register 21 (MAC Specific Control Register 2) according to speed of
> the loopback is operating.
>
> Tested working on Marvell88E1510 PHY for all speeds (1000/100/10Mbps).
>
> FIXME: Based on trial and error test, it seem 1G need to have delay between
> soft reset and loopback enablement.
>
> Fixes: 014068dcb5b1 ("net: phy: genphy_loopback: add link speed configuration")
> Cc: <stable@xxxxxxxxxxxxxxx> # 5.15.x
> Signed-off-by: Mohammad Athari Bin Ismail <mohammad.athari.ismail@xxxxxxxxx>
> ---
> v3 changelog:
> - Use phy_write() to configure speed for BMCR.
> - Add error handling.
> All commented by Russell King <linux@xxxxxxxxxxxxxxx>
>
> v2 changelog:
> - For loopback enabled, add bit-6 and bit-13 configuration in both Page
> 0 Register 0 and Page 2 Register 21. Commented by Heiner Kallweit
> <hkallweit1@xxxxxxxxx>.
> - For loopback disabled, follow genphy_loopback() implementation
> ---
> drivers/net/phy/marvell.c | 56 ++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 55 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
> index 4fcfca4e1702..5c371c2de9a0 100644
> --- a/drivers/net/phy/marvell.c
> +++ b/drivers/net/phy/marvell.c
> @@ -189,6 +189,8 @@
> #define MII_88E1510_GEN_CTRL_REG_1_MODE_RGMII_SGMII 0x4
> #define MII_88E1510_GEN_CTRL_REG_1_RESET 0x8000 /* Soft reset */
>
> +#define MII_88E1510_MSCR_2 0x15
> +
> #define MII_VCT5_TX_RX_MDI0_COUPLING 0x10
> #define MII_VCT5_TX_RX_MDI1_COUPLING 0x11
> #define MII_VCT5_TX_RX_MDI2_COUPLING 0x12
> @@ -1932,6 +1934,58 @@ static void marvell_get_stats(struct phy_device *phydev,
> data[i] = marvell_get_stat(phydev, i);
> }
>
> +static int marvell_loopback(struct phy_device *phydev, bool enable)
Marvell PHY's use different bits for the loopback speed, e.g.:
88E1510 bits 13, 6
88E1545 bits 2..0
Your function is usable with certain Marvell PHY's only, therefore
the function name is misleading. At a first glance I see two options:
1. Leave the function name and add a version-specific section that returns
an error for (not yet) supported versions.
2. Name it m88e1510_loopback()
> +{
> + int err;
> +
> + if (enable) {
> + u16 bmcr_ctl = 0, mscr2_ctl = 0;
> +
> + if (phydev->speed == SPEED_1000)
> + bmcr_ctl = BMCR_SPEED1000;
> + else if (phydev->speed == SPEED_100)
> + bmcr_ctl = BMCR_SPEED100;
> +
> + if (phydev->duplex == DUPLEX_FULL)
> + bmcr_ctl |= BMCR_FULLDPLX;
> +
> + err = phy_write(phydev, MII_BMCR, bmcr_ctl);
> + if (err < 0)
> + return err;
> +
> + if (phydev->speed == SPEED_1000)
> + mscr2_ctl = BMCR_SPEED1000;
> + else if (phydev->speed == SPEED_100)
> + mscr2_ctl = BMCR_SPEED100;
> +
> + err = phy_modify_paged(phydev, MII_MARVELL_MSCR_PAGE,
> + MII_88E1510_MSCR_2, BMCR_SPEED1000 |
> + BMCR_SPEED100, mscr2_ctl);
> + if (err < 0)
> + return err;
> +
> + /* Need soft reset to have speed configuration takes effect */
> + err = genphy_soft_reset(phydev);
> + if (err < 0)
> + return err;
> +
> + /* FIXME: Based on trial and error test, it seem 1G need to have
> + * delay between soft reset and loopback enablement.
> + */
> + if (phydev->speed == SPEED_1000)
> + msleep(1000);
> +
> + return phy_modify(phydev, MII_BMCR, BMCR_LOOPBACK,
> + BMCR_LOOPBACK);
> + } else {
> + err = phy_modify(phydev, MII_BMCR, BMCR_LOOPBACK, 0);
> + if (err < 0)
> + return err;
> +
> + return phy_config_aneg(phydev);
> + }
> +}
> +
> static int marvell_vct5_wait_complete(struct phy_device *phydev)
> {
> int i;
> @@ -3078,7 +3132,7 @@ static struct phy_driver marvell_drivers[] = {
> .get_sset_count = marvell_get_sset_count,
> .get_strings = marvell_get_strings,
> .get_stats = marvell_get_stats,
> - .set_loopback = genphy_loopback,
> + .set_loopback = marvell_loopback,
> .get_tunable = m88e1011_get_tunable,
> .set_tunable = m88e1011_set_tunable,
> .cable_test_start = marvell_vct7_cable_test_start,
