[PATCH net 1/2] Revert "net: bcmgenet: use RGMII loopback for MAC reset"

From: Doug Berger
Date: Mon Mar 16 2020 - 17:45:32 EST


This reverts commit 3a55402c93877d291b0a612d25edb03d1b4b93ac.

This is not a good solution when connecting to an external switch
that may not support the isolation of the TXC signal resulting in
output driver contention on the pin.

A different solution is necessary.

Signed-off-by: Doug Berger <opendmb@xxxxxxxxx>
---
drivers/net/ethernet/broadcom/genet/bcmgenet.c | 2 ++
drivers/net/ethernet/broadcom/genet/bcmmii.c | 34 --------------------------
2 files changed, 2 insertions(+), 34 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
index e50a15397e11..c8ac2d83208f 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
@@ -1989,6 +1989,8 @@ static void reset_umac(struct bcmgenet_priv *priv)

/* 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);
+ udelay(2);
+ bcmgenet_umac_writel(priv, 0, UMAC_CMD);
}

static void bcmgenet_intr_disable(struct bcmgenet_priv *priv)
diff --git a/drivers/net/ethernet/broadcom/genet/bcmmii.c b/drivers/net/ethernet/broadcom/genet/bcmmii.c
index 10244941a7a6..69e80fb6e039 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmmii.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmmii.c
@@ -181,38 +181,8 @@ 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 +252,6 @@ 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);

--
2.7.4