net: stmmac: add clocks management for gmac driver

commit 5ec5582 upstream.

This patch intends to add clocks management for stmmac driver:

If CONFIG_PM enabled:
1. Keep clocks disabled after driver probed.
2. Enable clocks when up the net device, and disable clocks when down
the net device.

If CONFIG_PM disabled:
Keep clocks always enabled after driver probed.

Note:
1. It is fine for ethtool, since the way of implementing ethtool_ops::begin
in stmmac is only can be accessed when interface is enabled, so the clocks
are ticked.
2. The MDIO bus has a different life cycle to the MAC, need ensure
clocks are enabled when _mdio_read/write() need clocks, because these
functions can be called while the interface it not opened.

Stable backport notes:
When run below command to remove ethernet driver on
stratix10 platform, there will be warning trace as below:

$ cd /sys/class/net/eth0/device/driver/
$ echo ff800000.ethernet > unbind

WARNING: CPU: 3 PID: 386 at drivers/clk/clk.c:810 clk_core_unprepare+0x114/0x274
Modules linked in: sch_fq_codel
CPU: 3 PID: 386 Comm: sh Tainted: G        W         5.10.74-yocto-standard #1
Hardware name: SoCFPGA Stratix 10 SoCDK (DT)
pstate: 00000005 (nzcv daif -PAN -UAO -TCO BTYPE=--)
pc : clk_core_unprepare+0x114/0x274
lr : clk_core_unprepare+0x114/0x274
sp : ffff800011bdbb10
clk_core_unprepare+0x114/0x274
 clk_unprepare+0x38/0x50
 stmmac_remove_config_dt+0x40/0x80
 stmmac_pltfr_remove+0x64/0x80
 platform_drv_remove+0x38/0x60
 ... ..
 el0_sync_handler+0x1a4/0x1b0
 el0_sync+0x180/0x1c0
This issue is introduced by introducing upstream commit 8f26910
("net: stmmac: disable clocks in stmmac_remove_config_dt()")

But in latest mainline kernel, there is no this issue. Because this
patch improved clocks management for stmmac driver.
Therefore, backport it and its fixing patches to stable kernel v5.10.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: stable@vger.kernel.org
Signed-off-by: Meng Li <Meng.Li@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Joakim Zhang

drivers/net/ethernet/stmicro/stmmac/stmmac.h

@@ -270,6 +270,7 @@ void stmmac_disable_eee_mode(struct stmmac_priv *priv);
 bool stmmac_eee_init(struct stmmac_priv *priv);
 int stmmac_reinit_queues(struct net_device *dev, u32 rx_cnt, u32 tx_cnt);
 int stmmac_reinit_ringparam(struct net_device *dev, u32 rx_size, u32 tx_size);
+int stmmac_bus_clks_config(struct stmmac_priv *priv, bool enabled);
 
 #if IS_ENABLED(CONFIG_STMMAC_SELFTESTS)
 void stmmac_selftest_run(struct net_device *dev,

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -28,6 +28,7 @@
 #include <linux/if_vlan.h>
 #include <linux/dma-mapping.h>
 #include <linux/slab.h>
+#include <linux/pm_runtime.h>
 #include <linux/prefetch.h>
 #include <linux/pinctrl/consumer.h>
 #ifdef CONFIG_DEBUG_FS
@@ -113,6 +114,28 @@ static void stmmac_exit_fs(struct net_device *dev);
 
 #define STMMAC_COAL_TIMER(x) (jiffies + usecs_to_jiffies(x))
 
+int stmmac_bus_clks_config(struct stmmac_priv *priv, bool enabled)
+{
+	int ret = 0;
+
+	if (enabled) {
+		ret = clk_prepare_enable(priv->plat->stmmac_clk);
+		if (ret)
+			return ret;
+		ret = clk_prepare_enable(priv->plat->pclk);
+		if (ret) {
+			clk_disable_unprepare(priv->plat->stmmac_clk);
+			return ret;
+		}
+	} else {
+		clk_disable_unprepare(priv->plat->stmmac_clk);
+		clk_disable_unprepare(priv->plat->pclk);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(stmmac_bus_clks_config);
+
 /**
  * stmmac_verify_args - verify the driver parameters.
  * Description: it checks the driver parameters and set a default in case of
@@ -2792,6 +2815,12 @@ static int stmmac_open(struct net_device *dev)
 	u32 chan;
 	int ret;
 
+	ret = pm_runtime_get_sync(priv->device);
+	if (ret < 0) {
+		pm_runtime_put_noidle(priv->device);
+		return ret;
+	}
+
 	if (priv->hw->pcs != STMMAC_PCS_TBI &&
 	    priv->hw->pcs != STMMAC_PCS_RTBI &&
 	    priv->hw->xpcs == NULL) {
@@ -2800,7 +2829,7 @@ static int stmmac_open(struct net_device *dev)
 			netdev_err(priv->dev,
 				   "%s: Cannot attach to PHY (error: %d)\n",
 				   __func__, ret);
-			return ret;
+			goto init_phy_error;
 		}
 	}
 
@@ -2915,6 +2944,8 @@ static int stmmac_open(struct net_device *dev)
 	free_dma_desc_resources(priv);
 dma_desc_error:
 	phylink_disconnect_phy(priv->phylink);
+init_phy_error:
+	pm_runtime_put(priv->device);
 	return ret;
 }
 
@@ -2965,6 +2996,8 @@ static int stmmac_release(struct net_device *dev)
 
 	stmmac_release_ptp(priv);
 
+	pm_runtime_put(priv->device);
+
 	return 0;
 }
 
@@ -4616,6 +4649,12 @@ static int stmmac_vlan_rx_kill_vid(struct net_device *ndev, __be16 proto, u16 vi
 	bool is_double = false;
 	int ret;
 
+	ret = pm_runtime_get_sync(priv->device);
+	if (ret < 0) {
+		pm_runtime_put_noidle(priv->device);
+		return ret;
+	}
+
 	if (be16_to_cpu(proto) == ETH_P_8021AD)
 		is_double = true;
 
@@ -4624,10 +4663,15 @@ static int stmmac_vlan_rx_kill_vid(struct net_device *ndev, __be16 proto, u16 vi
 	if (priv->hw->num_vlan) {
 		ret = stmmac_del_hw_vlan_rx_fltr(priv, ndev, priv->hw, proto, vid);
 		if (ret)
-			return ret;
+			goto del_vlan_error;
 	}
 
-	return stmmac_vlan_update(priv, is_double);
+	ret = stmmac_vlan_update(priv, is_double);
+
+del_vlan_error:
+	pm_runtime_put(priv->device);
+
+	return ret;
 }
 
 static const struct net_device_ops stmmac_netdev_ops = {
@@ -5066,6 +5110,10 @@ int stmmac_dvr_probe(struct device *device,
 
 	stmmac_check_pcs_mode(priv);
 
+	pm_runtime_get_noresume(device);
+	pm_runtime_set_active(device);
+	pm_runtime_enable(device);
+
 	if (priv->hw->pcs != STMMAC_PCS_TBI &&
 	    priv->hw->pcs != STMMAC_PCS_RTBI) {
 		/* MDIO bus Registration */
@@ -5103,6 +5151,11 @@ int stmmac_dvr_probe(struct device *device,
 	stmmac_init_fs(ndev);
 #endif
 
+	/* Let pm_runtime_put() disable the clocks.
+	 * If CONFIG_PM is not enabled, the clocks will stay powered.
+	 */
+	pm_runtime_put(device);
+
 	return ret;
 
 error_serdes_powerup:
@@ -5117,6 +5170,7 @@ int stmmac_dvr_probe(struct device *device,
 	stmmac_napi_del(ndev);
 error_hw_init:
 	destroy_workqueue(priv->wq);
+	stmmac_bus_clks_config(priv, false);
 
 	return ret;
 }
@@ -5152,8 +5206,8 @@ int stmmac_dvr_remove(struct device *dev)
 	phylink_destroy(priv->phylink);
 	if (priv->plat->stmmac_rst)
 		reset_control_assert(priv->plat->stmmac_rst);
-	clk_disable_unprepare(priv->plat->pclk);
-	clk_disable_unprepare(priv->plat->stmmac_clk);
+	pm_runtime_put(dev);
+	pm_runtime_disable(dev);
 	if (priv->hw->pcs != STMMAC_PCS_TBI &&
 	    priv->hw->pcs != STMMAC_PCS_RTBI)
 		stmmac_mdio_unregister(ndev);
@@ -5176,6 +5230,7 @@ int stmmac_suspend(struct device *dev)
 	struct net_device *ndev = dev_get_drvdata(dev);
 	struct stmmac_priv *priv = netdev_priv(ndev);
 	u32 chan;
+	int ret;
 
 	if (!ndev || !netif_running(ndev))
 		return 0;
@@ -5219,8 +5274,9 @@ int stmmac_suspend(struct device *dev)
 		pinctrl_pm_select_sleep_state(priv->device);
 		/* Disable clock in case of PWM is off */
 		clk_disable_unprepare(priv->plat->clk_ptp_ref);
-		clk_disable_unprepare(priv->plat->pclk);
-		clk_disable_unprepare(priv->plat->stmmac_clk);
+		ret = pm_runtime_force_suspend(dev);
+		if (ret)
+			return ret;
 	}
 	mutex_unlock(&priv->lock);
 
@@ -5286,8 +5342,9 @@ int stmmac_resume(struct device *dev)
 	} else {
 		pinctrl_pm_select_default_state(priv->device);
 		/* enable the clk previously disabled */
-		clk_prepare_enable(priv->plat->stmmac_clk);
-		clk_prepare_enable(priv->plat->pclk);
+		ret = pm_runtime_force_resume(dev);
+		if (ret)
+			return ret;
 		if (priv->plat->clk_ptp_ref)
 			clk_prepare_enable(priv->plat->clk_ptp_ref);
 		/* reset the phy so that it's ready */