linux-kernel - [PATCH net 2/4] net: stmmac: dwmac-sun8i: Balance internal PHY resource references

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Message-Id: <20210103111744.34989-3-samuel@sholland.org>
Date:   Sun,  3 Jan 2021 05:17:42 -0600
From:   Samuel Holland <samuel@...lland.org>
To:     Giuseppe Cavallaro <peppe.cavallaro@...com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        Jose Abreu <joabreu@...opsys.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Maxime Ripard <mripard@...nel.org>,
        Chen-Yu Tsai <wens@...e.org>,
        Jernej Skrabec <jernej.skrabec@...l.net>,
        Corentin Labbe <clabbe@...libre.com>
Cc:     Ondrej Jirman <megous@...ous.com>, netdev@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-sunxi@...glegroups.com, Samuel Holland <samuel@...lland.org>
Subject: [PATCH net 2/4] net: stmmac: dwmac-sun8i: Balance internal PHY resource references

While stmmac_pltfr_remove calls sun8i_dwmac_exit, the sun8i_dwmac_init
and sun8i_dwmac_exit functions are also called by the stmmac_platform
suspend/resume callbacks. They may be called many times during the
device's lifetime and should not release resources used by the driver.

Furthermore, there was no error handling in case registering the MDIO
mux failed during probe, and the EPHY clock was never released at all.

Fix all of these issues by moving the deinitialization code to a driver
removal callback. Also ensure the EPHY is powered down before removal.

Fixes: 634db83b8265 ("net: stmmac: dwmac-sun8i: Handle integrated/external MDIOs")
Signed-off-by: Samuel Holland <samuel@...lland.org>
---
 .../net/ethernet/stmicro/stmmac/dwmac-sun8i.c | 27 ++++++++++++++-----
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
index b20f261fce5b..a05dee5d4584 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
@@ -1004,17 +1004,12 @@ static void sun8i_dwmac_exit(struct platform_device *pdev, void *priv)
 	struct sunxi_priv_data *gmac = priv;
 
 	if (gmac->variant->soc_has_internal_phy) {
-		/* sun8i_dwmac_exit could be called with mdiomux uninit */
-		if (gmac->mux_handle)
-			mdio_mux_uninit(gmac->mux_handle);
 		if (gmac->internal_phy_powered)
 			sun8i_dwmac_unpower_internal_phy(gmac);
 	}
 
 	sun8i_dwmac_unset_syscon(gmac);
 
-	reset_control_put(gmac->rst_ephy);
-
 	clk_disable_unprepare(gmac->tx_clk);
 
 	if (gmac->regulator)
@@ -1244,6 +1239,8 @@ static int sun8i_dwmac_probe(struct platform_device *pdev)
 
 	return ret;
 dwmac_mux:
+	reset_control_put(gmac->rst_ephy);
+	clk_put(gmac->ephy_clk);
 	sun8i_dwmac_unset_syscon(gmac);
 dwmac_remove:
 	stmmac_dvr_remove(&pdev->dev);
@@ -1255,6 +1252,24 @@ static int sun8i_dwmac_probe(struct platform_device *pdev)
 	return ret;
 }
 
+static int sun8i_dwmac_remove(struct platform_device *pdev)
+{
+	struct net_device *ndev = platform_get_drvdata(pdev);
+	struct stmmac_priv *priv = netdev_priv(ndev);
+	struct sunxi_priv_data *gmac = priv->plat->bsp_priv;
+
+	if (gmac->variant->soc_has_internal_phy) {
+		mdio_mux_uninit(gmac->mux_handle);
+		sun8i_dwmac_unpower_internal_phy(gmac);
+		reset_control_put(gmac->rst_ephy);
+		clk_put(gmac->ephy_clk);
+	}
+
+	stmmac_pltfr_remove(pdev);
+
+	return 0;
+}
+
 static const struct of_device_id sun8i_dwmac_match[] = {
 	{ .compatible = "allwinner,sun8i-h3-emac",
 		.data = &emac_variant_h3 },
@@ -1274,7 +1289,7 @@ MODULE_DEVICE_TABLE(of, sun8i_dwmac_match);
 
 static struct platform_driver sun8i_dwmac_driver = {
 	.probe  = sun8i_dwmac_probe,
-	.remove = stmmac_pltfr_remove,
+	.remove = sun8i_dwmac_remove,
 	.driver = {
 		.name           = "dwmac-sun8i",
 		.pm		= &stmmac_pltfr_pm_ops,
-- 
2.26.2