Merge branch 'net-bcmgenet-revisit-MAC-reset'

Doug Berger says:

====================
net: bcmgenet: revisit MAC reset

Commit 3a55402c9387 ("net: bcmgenet: use RGMII loopback for MAC
reset") was intended to resolve issues with reseting the UniMAC
core within the GENET block by providing better control over the
clocks used by the UniMAC core. Unfortunately, it is not
compatible with all of the supported system configurations so an
alternative method must be applied.

This commit set provides such an alternative. The first commit
reverts the previous change and the second commit provides the
alternative reset sequence that addresses the concerns observed
with the previous implementation.

This replacement implementation should be applied to the stable
branches wherever commit 3a55402c9387 ("net: bcmgenet: use RGMII
loopback for MAC reset") has been applied.

Unfortunately, reverting that commit may conflict with some
restructuring changes introduced by commit 4f8d81b77e66 ("net:
bcmgenet: Refactor register access in bcmgenet_mii_config").
The first commit in this set has been manually edited to
resolve the conflict on net/master. I would be happy to help
stable maintainers with resolving any such conflicts if they
occur. However, I do not expect that commit to have been
backported to stable branch so hopefully the revert can be
applied cleanly.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 16 insertions, 40 deletions

diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
index e50a15397e11..ce64b4e47feb 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
@@ -1965,6 +1965,8 @@ static void umac_enable_set(struct bcmgenet_priv *priv, u32 mask, bool enable)
 	u32 reg;
 
 	reg = bcmgenet_umac_readl(priv, UMAC_CMD);
+	if (reg & CMD_SW_RESET)
+		return;
 	if (enable)
 		reg |= mask;
 	else
@@ -1984,11 +1986,9 @@ static void reset_umac(struct bcmgenet_priv *priv)
 	bcmgenet_rbuf_ctrl_set(priv, 0);
 	udelay(10);
 
-	/* disable MAC while updating its registers */
-	bcmgenet_umac_writel(priv, 0, UMAC_CMD);
-
-	/* issue soft reset with (rg)mii loopback to ensure a stable rxclk */
-	bcmgenet_umac_writel(priv, CMD_SW_RESET | CMD_LCL_LOOP_EN, UMAC_CMD);
+	/* issue soft reset and disable MAC while updating its registers */
+	bcmgenet_umac_writel(priv, CMD_SW_RESET, UMAC_CMD);
+	udelay(2);
 }
 
 static void bcmgenet_intr_disable(struct bcmgenet_priv *priv)
diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet_wol.c b/drivers/net/ethernet/broadcom/genet/bcmgenet_wol.c
index ea20d94bd050..c9a43695b182 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet_wol.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet_wol.c
@@ -132,8 +132,12 @@ int bcmgenet_wol_power_down_cfg(struct bcmgenet_priv *priv,
 		return -EINVAL;
 	}
 
-	/* disable RX */
+	/* Can't suspend with WoL if MAC is still in reset */
 	reg = bcmgenet_umac_readl(priv, UMAC_CMD);
+	if (reg & CMD_SW_RESET)
+		reg &= ~CMD_SW_RESET;
+
+	/* disable RX */
 	reg &= ~CMD_RX_EN;
 	bcmgenet_umac_writel(priv, reg, UMAC_CMD);
 	mdelay(10);
diff --git a/drivers/net/ethernet/broadcom/genet/bcmmii.c b/drivers/net/ethernet/broadcom/genet/bcmmii.c
index 10244941a7a6..b5930f80039d 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmmii.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmmii.c
@@ -95,6 +95,12 @@ void bcmgenet_mii_setup(struct net_device *dev)
 			       CMD_HD_EN |
 			       CMD_RX_PAUSE_IGNORE | CMD_TX_PAUSE_IGNORE);
 		reg |= cmd_bits;
+		if (reg & CMD_SW_RESET) {
+			reg &= ~CMD_SW_RESET;
+			bcmgenet_umac_writel(priv, reg, UMAC_CMD);
+			udelay(2);
+			reg |= CMD_TX_EN | CMD_RX_EN;
+		}
 		bcmgenet_umac_writel(priv, reg, UMAC_CMD);
 	} else {
 		/* done if nothing has changed */
@@ -181,38 +187,8 @@ int bcmgenet_mii_config(struct net_device *dev, bool init)
 	const char *phy_name = NULL;
 	u32 id_mode_dis = 0;
 	u32 port_ctrl;
-	int bmcr = -1;
-	int ret;
 	u32 reg;
 
-	/* MAC clocking workaround during reset of umac state machines */
-	reg = bcmgenet_umac_readl(priv, UMAC_CMD);
-	if (reg & CMD_SW_RESET) {
-		/* An MII PHY must be isolated to prevent TXC contention */
-		if (priv->phy_interface == PHY_INTERFACE_MODE_MII) {
-			ret = phy_read(phydev, MII_BMCR);
-			if (ret >= 0) {
-				bmcr = ret;
-				ret = phy_write(phydev, MII_BMCR,
-						bmcr | BMCR_ISOLATE);
-			}
-			if (ret) {
-				netdev_err(dev, "failed to isolate PHY\n");
-				return ret;
-			}
-		}
-		/* Switch MAC clocking to RGMII generated clock */
-		bcmgenet_sys_writel(priv, PORT_MODE_EXT_GPHY, SYS_PORT_CTRL);
-		/* Ensure 5 clks with Rx disabled
-		 * followed by 5 clks with Reset asserted
-		 */
-		udelay(4);
-		reg &= ~(CMD_SW_RESET | CMD_LCL_LOOP_EN);
-		bcmgenet_umac_writel(priv, reg, UMAC_CMD);
-		/* Ensure 5 more clocks before Rx is enabled */
-		udelay(2);
-	}
-
 	switch (priv->phy_interface) {
 	case PHY_INTERFACE_MODE_INTERNAL:
 		phy_name = "internal PHY";
@@ -282,10 +258,6 @@ int bcmgenet_mii_config(struct net_device *dev, bool init)
 
 	bcmgenet_sys_writel(priv, port_ctrl, SYS_PORT_CTRL);
 
-	/* Restore the MII PHY after isolation */
-	if (bmcr >= 0)
-		phy_write(phydev, MII_BMCR, bmcr);
-
 	priv->ext_phy = !priv->internal_phy &&
 			(priv->phy_interface != PHY_INTERFACE_MODE_MOCA);