net/fsl: xgmac_mdio: Support preamble suppression

Support the standard "suppress-preamble" attribute to disable preamble
generation.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/freescale/xgmac_mdio.c b/drivers/net/ethernet/freescale/xgmac_mdio.c
index 40442d6..18bf237 100644 (file)
--- a/drivers/net/ethernet/freescale/xgmac_mdio.c
+++ b/drivers/net/ethernet/freescale/xgmac_mdio.c
@@ -39,6 +39,7 @@ struct tgec_mdio_controller {
 #define MDIO_STAT_CLKDIV(x)    (((x>>1) & 0xff) << 8)
 #define MDIO_STAT_BSY          BIT(0)
 #define MDIO_STAT_RD_ER                BIT(1)
+#define MDIO_STAT_PRE_DIS      BIT(5)
 #define MDIO_CTL_DEV_ADDR(x)   (x & 0x1f)
 #define MDIO_CTL_PORT_ADDR(x)  ((x & 0x1f) << 5)
 #define MDIO_CTL_PRE_DIS       BIT(10)
@@ -254,6 +255,21 @@ irq_restore:
        return ret;
 }
 
+static void xgmac_mdio_set_suppress_preamble(struct mii_bus *bus)
+{
+       struct mdio_fsl_priv *priv = (struct mdio_fsl_priv *)bus->priv;
+       struct tgec_mdio_controller __iomem *regs = priv->mdio_base;
+       struct device *dev = bus->parent;
+       u32 mdio_stat;
+
+       if (!device_property_read_bool(dev, "suppress-preamble"))
+               return;
+
+       mdio_stat = xgmac_read32(&regs->mdio_stat, priv->is_little_endian);
+       mdio_stat |= MDIO_STAT_PRE_DIS;
+       xgmac_write32(mdio_stat, &regs->mdio_stat, priv->is_little_endian);
+}
+
 static int xgmac_mdio_probe(struct platform_device *pdev)
 {
        struct fwnode_handle *fwnode;
@@ -301,6 +317,8 @@ static int xgmac_mdio_probe(struct platform_device *pdev)
        priv->has_a011043 = device_property_read_bool(&pdev->dev,
                                                      "fsl,erratum-a011043");
 
+       xgmac_mdio_set_suppress_preamble(bus);
+
        fwnode = pdev->dev.fwnode;
        if (is_of_node(fwnode))
                ret = of_mdiobus_register(bus, to_of_node(fwnode));