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

[Samuel Holland]

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 <sam...@sholland.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

[Chen-Yu Tsai]

On Sun, Jan 3, 2021 at 7:17 PM Samuel Holland <sam...@sholland.org> wrote:
>
> 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 <sam...@sholland.org>

Reviewed-by: Chen-Yu Tsai <we...@csie.org>