net: stmmac: dwc-qos: calibrate tegra with mdio bus idle

Thierry states that there are prerequists for Tegra's calibration
that should be met before starting calibration - both the RGMII and
MDIO interfaces should be idle.

This commit adds the necessary MII bus locking to ensure that the MDIO
interface is idle during calibration.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://patch.msgid.link/E1u7EYR-001ZAS-Cr@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c
index fa900b4991d06252bd5f002d584457178a7abe40..09ae16e026eb4d8bdd0ceed33981c488d49b6f36 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c
@@ -136,10 +136,11 @@ static int dwc_qos_probe(struct platform_device *pdev,
 #define AUTO_CAL_STATUS 0x880c
 #define  AUTO_CAL_STATUS_ACTIVE BIT(31)
 
-static void tegra_eqos_fix_speed(void *priv, int speed, unsigned int mode)
+static void tegra_eqos_fix_speed(void *bsp_priv, int speed, unsigned int mode)
 {
-       struct tegra_eqos *eqos = priv;
+       struct tegra_eqos *eqos = bsp_priv;
        bool needs_calibration = false;
+       struct stmmac_priv *priv;
        u32 value;
        int err;
 
@@ -158,6 +159,11 @@ static void tegra_eqos_fix_speed(void *priv, int speed, unsigned int mode)
        }
 
        if (needs_calibration) {
+               priv = netdev_priv(dev_get_drvdata(eqos->dev));
+
+               /* Calibration should be done with the MDIO bus idle */
+               mutex_lock(&priv->mii->mdio_lock);
+
                /* calibrate */
                value = readl(eqos->regs + SDMEMCOMPPADCTRL);
                value |= SDMEMCOMPPADCTRL_PAD_E_INPUT_OR_E_PWRD;
@@ -191,6 +197,8 @@ static void tegra_eqos_fix_speed(void *priv, int speed, unsigned int mode)
                value = readl(eqos->regs + SDMEMCOMPPADCTRL);
                value &= ~SDMEMCOMPPADCTRL_PAD_E_INPUT_OR_E_PWRD;
                writel(value, eqos->regs + SDMEMCOMPPADCTRL);
+
+               mutex_unlock(&priv->mii->mdio_lock);
        } else {
                value = readl(eqos->regs + AUTO_CAL_CONFIG);
                value &= ~AUTO_CAL_CONFIG_ENABLE;