net: phy: bcm7xx: add jumbo frame configuration to PHY

The BCM7XX PHY family requires special configuration to pass jumbo
frames. Do that during initial PHY setup.

Signed-off-by: Murali Krishna Policharla <murali.policharla@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/bcm-phy-lib.c

@@ -423,6 +423,28 @@ int bcm_phy_28nm_a0b0_afe_config_init(struct phy_device *phydev)
 }
 EXPORT_SYMBOL_GPL(bcm_phy_28nm_a0b0_afe_config_init);
 
+int bcm_phy_enable_jumbo(struct phy_device *phydev)
+{
+	int ret;
+
+	ret = bcm54xx_auxctl_read(phydev, MII_BCM54XX_AUXCTL_SHDWSEL_AUXCTL);
+	if (ret < 0)
+		return ret;
+
+	/* Enable extended length packet reception */
+	ret = bcm54xx_auxctl_write(phydev, MII_BCM54XX_AUXCTL_SHDWSEL_AUXCTL,
+				   ret | MII_BCM54XX_AUXCTL_ACTL_EXT_PKT_LEN);
+	if (ret < 0)
+		return ret;
+
+	/* Enable the elastic FIFO for raising the transmission limit from
+	 * 4.5KB to 10KB, at the expense of an additional 16 ns in propagation
+	 * latency.
+	 */
+	return phy_set_bits(phydev, MII_BCM54XX_ECR, MII_BCM54XX_ECR_FIFOE);
+}
+EXPORT_SYMBOL_GPL(bcm_phy_enable_jumbo);
+
 MODULE_DESCRIPTION("Broadcom PHY Library");
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Broadcom Corporation");

drivers/net/phy/bcm-phy-lib.h

@@ -65,5 +65,6 @@ void bcm_phy_get_stats(struct phy_device *phydev, u64 *shadow,
 		       struct ethtool_stats *stats, u64 *data);
 void bcm_phy_r_rc_cal_reset(struct phy_device *phydev);
 int bcm_phy_28nm_a0b0_afe_config_init(struct phy_device *phydev);
+int bcm_phy_enable_jumbo(struct phy_device *phydev);
 
 #endif /* _LINUX_BCM_PHY_LIB_H */

drivers/net/phy/bcm7xxx.c

@@ -178,6 +178,10 @@ static int bcm7xxx_28nm_config_init(struct phy_device *phydev)
 		break;
 	}
 
+	if (ret)
+		return ret;
+
+	ret =  bcm_phy_enable_jumbo(phydev);
 	if (ret)
 		return ret;
 

include/linux/brcmphy.h

@@ -79,6 +79,7 @@
 #define MII_BCM54XX_ECR		0x10	/* BCM54xx extended control register */
 #define MII_BCM54XX_ECR_IM	0x1000	/* Interrupt mask */
 #define MII_BCM54XX_ECR_IF	0x0800	/* Interrupt force */
+#define MII_BCM54XX_ECR_FIFOE	0x0001	/* FIFO elasticity */
 
 #define MII_BCM54XX_ESR		0x11	/* BCM54xx extended status register */
 #define MII_BCM54XX_ESR_IS	0x1000	/* Interrupt status */
@@ -119,6 +120,7 @@
 #define MII_BCM54XX_AUXCTL_SHDWSEL_AUXCTL	0x00
 #define MII_BCM54XX_AUXCTL_ACTL_TX_6DB		0x0400
 #define MII_BCM54XX_AUXCTL_ACTL_SMDSP_ENA	0x0800
+#define MII_BCM54XX_AUXCTL_ACTL_EXT_PKT_LEN	0x4000
 
 #define MII_BCM54XX_AUXCTL_SHDWSEL_MISC			0x07
 #define MII_BCM54XX_AUXCTL_SHDWSEL_MISC_WIRESPEED_EN	0x0010