net: phy: at803x: add disable hibernation mode support

When the cable is unplugged, the Atheros AR803x PHYs will enter
hibernation mode after about 10 seconds if the hibernation mode
is enabled and will not provide any clock to the MAC. But for
some MACs, this feature might cause unexpected issues due to the
logic of MACs.
Taking SYNP MAC (stmmac) as an example, if the cable is unplugged
and the "eth0" interface is down, the AR803x PHY will enter
hibernation mode. Then perform the "ifconfig eth0 up" operation,
the stmmac can't be able to complete the software reset operation
and fail to init it's own DMA. Therefore, the "eth0" interface is
failed to ifconfig up. Why does it cause this issue? The truth is
that the software reset operation of the stmmac is designed to
depend on the RX_CLK of PHY.
So, this patch offers an option for the user to determine whether
to disable the hibernation mode of AR803x PHYs.

Signed-off-by: Wei Fang <wei.fang@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/phy/at803x.c b/drivers/net/phy/at803x.c
index 59fe356942b51e18c8c763d455d4b4d1da091e0b..11ebd59bf2eb675b4bae678363270bc8c8a7631f 100644 (file)
--- a/drivers/net/phy/at803x.c
+++ b/drivers/net/phy/at803x.c
@@ -115,6 +115,7 @@
 #define AT803X_DEBUG_REG_HIB_CTRL              0x0b
 #define   AT803X_DEBUG_HIB_CTRL_SEL_RST_80U    BIT(10)
 #define   AT803X_DEBUG_HIB_CTRL_EN_ANY_CHANGE  BIT(13)
+#define   AT803X_DEBUG_HIB_CTRL_PS_HIB_EN      BIT(15)
 
 #define AT803X_DEBUG_REG_3C                    0x3C
 
@@ -192,6 +193,9 @@
 #define AT803X_KEEP_PLL_ENABLED                        BIT(0)
 #define AT803X_DISABLE_SMARTEEE                        BIT(1)
 
+/* disable hibernation mode */
+#define AT803X_DISABLE_HIBERNATION_MODE                BIT(2)
+
 /* ADC threshold */
 #define QCA808X_PHY_DEBUG_ADC_THRESHOLD                0x2c80
 #define QCA808X_ADC_THRESHOLD_MASK             GENMASK(7, 0)
@@ -730,6 +734,9 @@ static int at803x_parse_dt(struct phy_device *phydev)
        if (of_property_read_bool(node, "qca,disable-smarteee"))
                priv->flags |= AT803X_DISABLE_SMARTEEE;
 
+       if (of_property_read_bool(node, "qca,disable-hibernation-mode"))
+               priv->flags |= AT803X_DISABLE_HIBERNATION_MODE;
+
        if (!of_property_read_u32(node, "qca,smarteee-tw-us-1g", &tw)) {
                if (!tw || tw > 255) {
                        phydev_err(phydev, "invalid qca,smarteee-tw-us-1g\n");
@@ -999,6 +1006,20 @@ static int at8031_pll_config(struct phy_device *phydev)
                                             AT803X_DEBUG_PLL_ON, 0);
 }
 
+static int at803x_hibernation_mode_config(struct phy_device *phydev)
+{
+       struct at803x_priv *priv = phydev->priv;
+
+       /* The default after hardware reset is hibernation mode enabled. After
+        * software reset, the value is retained.
+        */
+       if (!(priv->flags & AT803X_DISABLE_HIBERNATION_MODE))
+               return 0;
+
+       return at803x_debug_reg_mask(phydev, AT803X_DEBUG_REG_HIB_CTRL,
+                                        AT803X_DEBUG_HIB_CTRL_PS_HIB_EN, 0);
+}
+
 static int at803x_config_init(struct phy_device *phydev)
 {
        struct at803x_priv *priv = phydev->priv;
@@ -1051,6 +1072,10 @@ static int at803x_config_init(struct phy_device *phydev)
        if (ret < 0)
                return ret;
 
+       ret = at803x_hibernation_mode_config(phydev);
+       if (ret < 0)
+               return ret;
+
        /* Ar803x extended next page bit is enabled by default. Cisco
         * multigig switches read this bit and attempt to negotiate 10Gbps
         * rates even if the next page bit is disabled. This is incorrect