Merge branch 'mediatek-reset-flow'

Sean Wang says:

====================
mediatek: add enhancement into the existing reset flow

Current driver only resets DMA used by descriptor rings which
can't guarantee it can recover all various kinds of fatal
errors, so the patch
1) tries to reset the underlying hardware resource from scratch on
Mediatek SoC required for ethernet running.
2) refactors code in order to the reusability of existing code.
3) considers handling for race condition between the reset flow and
callbacks registered into core driver called about hardware accessing.
4) introduces power domain usage to hardware setup which leads to have
cleanly and completely restore to the state as the initial.

Changes since v1:
- fix the build error with module built causing undefined symbol for
  pinctrl_bind_pins, so using pinctrl_select_state instead accomplishes
  the pin mux setup during the reset process.
====================
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mediatek/mtk_eth_soc.c

@@ -18,6 +18,7 @@
 #include <linux/mfd/syscon.h>
 #include <linux/regmap.h>
 #include <linux/clk.h>
+#include <linux/pm_runtime.h>
 #include <linux/if_vlan.h>
 #include <linux/reset.h>
 #include <linux/tcp.h>
@@ -144,6 +145,9 @@ static void mtk_phy_link_adjust(struct net_device *dev)
 		  MAC_MCR_RX_EN | MAC_MCR_BACKOFF_EN |
 		  MAC_MCR_BACKPR_EN;
 
+	if (unlikely(test_bit(MTK_RESETTING, &mac->hw->state)))
+		return;
+
 	switch (mac->phy_dev->speed) {
 	case SPEED_1000:
 		mcr |= MAC_MCR_SPEED_1000;
@@ -230,7 +234,7 @@ static int mtk_phy_connect(struct mtk_mac *mac)
 {
 	struct mtk_eth *eth = mac->hw;
 	struct device_node *np;
-	u32 val, ge_mode;
+	u32 val;
 
 	np = of_parse_phandle(mac->of_node, "phy-handle", 0);
 	if (!np && of_phy_is_fixed_link(mac->of_node))
@@ -244,18 +248,18 @@ static int mtk_phy_connect(struct mtk_mac *mac)
 	case PHY_INTERFACE_MODE_RGMII_RXID:
 	case PHY_INTERFACE_MODE_RGMII_ID:
 	case PHY_INTERFACE_MODE_RGMII:
-		ge_mode = 0;
+		mac->ge_mode = 0;
 		break;
 	case PHY_INTERFACE_MODE_MII:
-		ge_mode = 1;
+		mac->ge_mode = 1;
 		break;
 	case PHY_INTERFACE_MODE_REVMII:
-		ge_mode = 2;
+		mac->ge_mode = 2;
 		break;
 	case PHY_INTERFACE_MODE_RMII:
 		if (!mac->id)
 			goto err_phy;
-		ge_mode = 3;
+		mac->ge_mode = 3;
 		break;
 	default:
 		goto err_phy;
@@ -264,7 +268,7 @@ static int mtk_phy_connect(struct mtk_mac *mac)
 	/* put the gmac into the right mode */
 	regmap_read(eth->ethsys, ETHSYS_SYSCFG0, &val);
 	val &= ~SYSCFG0_GE_MODE(SYSCFG0_GE_MASK, mac->id);
-	val |= SYSCFG0_GE_MODE(ge_mode, mac->id);
+	val |= SYSCFG0_GE_MODE(mac->ge_mode, mac->id);
 	regmap_write(eth->ethsys, ETHSYS_SYSCFG0, val);
 
 	mtk_phy_connect_node(eth, mac, np);
@@ -369,6 +373,9 @@ static int mtk_set_mac_address(struct net_device *dev, void *p)
 	if (ret)
 		return ret;
 
+	if (unlikely(test_bit(MTK_RESETTING, &mac->hw->state)))
+		return -EBUSY;
+
 	spin_lock_bh(&mac->hw->page_lock);
 	mtk_w32(mac->hw, (macaddr[0] << 8) | macaddr[1],
 		MTK_GDMA_MAC_ADRH(mac->id));
@@ -769,6 +776,9 @@ static int mtk_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	 */
 	spin_lock(&eth->page_lock);
 
+	if (unlikely(test_bit(MTK_RESETTING, &eth->state)))
+		goto drop;
+
 	tx_num = mtk_cal_txd_req(skb);
 	if (unlikely(atomic_read(&ring->free_count) <= tx_num)) {
 		mtk_stop_queue(eth);
@@ -841,6 +851,9 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
 
 		netdev = eth->netdev[mac];
 
+		if (unlikely(test_bit(MTK_RESETTING, &eth->state)))
+			goto release_desc;
+
 		/* alloc new buffer */
 		new_data = napi_alloc_frag(ring->frag_size);
 		if (unlikely(!new_data)) {
@@ -1413,15 +1426,44 @@ static int mtk_stop(struct net_device *dev)
 	return 0;
 }
 
-static int __init mtk_hw_init(struct mtk_eth *eth)
+static void ethsys_reset(struct mtk_eth *eth, u32 reset_bits)
 {
-	int err, i;
+	regmap_update_bits(eth->ethsys, ETHSYS_RSTCTRL,
+			   reset_bits,
+			   reset_bits);
+
+	usleep_range(1000, 1100);
+	regmap_update_bits(eth->ethsys, ETHSYS_RSTCTRL,
+			   reset_bits,
+			   ~reset_bits);
+	mdelay(10);
+}
+
+static int mtk_hw_init(struct mtk_eth *eth)
+{
+	int i, val;
+
+	if (test_and_set_bit(MTK_HW_INIT, &eth->state))
+		return 0;
 
-	/* reset the frame engine */
-	reset_control_assert(eth->rstc);
-	usleep_range(10, 20);
-	reset_control_deassert(eth->rstc);
-	usleep_range(10, 20);
+	pm_runtime_enable(eth->dev);
+	pm_runtime_get_sync(eth->dev);
+
+	clk_prepare_enable(eth->clks[MTK_CLK_ETHIF]);
+	clk_prepare_enable(eth->clks[MTK_CLK_ESW]);
+	clk_prepare_enable(eth->clks[MTK_CLK_GP1]);
+	clk_prepare_enable(eth->clks[MTK_CLK_GP2]);
+	ethsys_reset(eth, RSTCTRL_FE);
+	ethsys_reset(eth, RSTCTRL_PPE);
+
+	regmap_read(eth->ethsys, ETHSYS_SYSCFG0, &val);
+	for (i = 0; i < MTK_MAC_COUNT; i++) {
+		if (!eth->mac[i])
+			continue;
+		val &= ~SYSCFG0_GE_MODE(SYSCFG0_GE_MASK, eth->mac[i]->id);
+		val |= SYSCFG0_GE_MODE(eth->mac[i]->ge_mode, eth->mac[i]->id);
+	}
+	regmap_write(eth->ethsys, ETHSYS_SYSCFG0, val);
 
 	/* Set GE2 driving and slew rate */
 	regmap_write(eth->pctl, GPIO_DRV_SEL10, 0xa00);
@@ -1441,19 +1483,6 @@ static int __init mtk_hw_init(struct mtk_eth *eth)
 	/* Enable RX VLan Offloading */
 	mtk_w32(eth, 1, MTK_CDMP_EG_CTRL);
 
-	err = devm_request_irq(eth->dev, eth->irq[1], mtk_handle_irq_tx, 0,
-			       dev_name(eth->dev), eth);
-	if (err)
-		return err;
-	err = devm_request_irq(eth->dev, eth->irq[2], mtk_handle_irq_rx, 0,
-			       dev_name(eth->dev), eth);
-	if (err)
-		return err;
-
-	err = mtk_mdio_init(eth);
-	if (err)
-		return err;
-
 	/* disable delay and normal interrupt */
 	mtk_w32(eth, 0, MTK_QDMA_DELAY_INT);
 	mtk_w32(eth, 0, MTK_PDMA_DELAY_INT);
@@ -1485,6 +1514,22 @@ static int __init mtk_hw_init(struct mtk_eth *eth)
 	return 0;
 }
 
+static int mtk_hw_deinit(struct mtk_eth *eth)
+{
+	if (!test_and_clear_bit(MTK_HW_INIT, &eth->state))
+		return 0;
+
+	clk_disable_unprepare(eth->clks[MTK_CLK_GP2]);
+	clk_disable_unprepare(eth->clks[MTK_CLK_GP1]);
+	clk_disable_unprepare(eth->clks[MTK_CLK_ESW]);
+	clk_disable_unprepare(eth->clks[MTK_CLK_ETHIF]);
+
+	pm_runtime_put_sync(eth->dev);
+	pm_runtime_disable(eth->dev);
+
+	return 0;
+}
+
 static int __init mtk_init(struct net_device *dev)
 {
 	struct mtk_mac *mac = netdev_priv(dev);
@@ -1543,6 +1588,12 @@ static void mtk_pending_work(struct work_struct *work)
 
 	rtnl_lock();
 
+	dev_dbg(eth->dev, "[%s][%d] reset\n", __func__, __LINE__);
+
+	while (test_and_set_bit_lock(MTK_RESETTING, &eth->state))
+		cpu_relax();
+
+	dev_dbg(eth->dev, "[%s][%d] mtk_stop starts\n", __func__, __LINE__);
 	/* stop all devices to make sure that dma is properly shut down */
 	for (i = 0; i < MTK_MAC_COUNT; i++) {
 		if (!eth->netdev[i])
@@ -1550,6 +1601,27 @@ static void mtk_pending_work(struct work_struct *work)
 		mtk_stop(eth->netdev[i]);
 		__set_bit(i, &restart);
 	}
+	dev_dbg(eth->dev, "[%s][%d] mtk_stop ends\n", __func__, __LINE__);
+
+	/* restart underlying hardware such as power, clock, pin mux
+	 * and the connected phy
+	 */
+	mtk_hw_deinit(eth);
+
+	if (eth->dev->pins)
+		pinctrl_select_state(eth->dev->pins->p,
+				     eth->dev->pins->default_state);
+	mtk_hw_init(eth);
+
+	for (i = 0; i < MTK_MAC_COUNT; i++) {
+		if (!eth->mac[i] ||
+		    of_phy_is_fixed_link(eth->mac[i]->of_node))
+			continue;
+		err = phy_init_hw(eth->mac[i]->phy_dev);
+		if (err)
+			dev_err(eth->dev, "%s: PHY init failed.\n",
+				eth->netdev[i]->name);
+	}
 
 	/* restart DMA and enable IRQs */
 	for (i = 0; i < MTK_MAC_COUNT; i++) {
@@ -1562,20 +1634,44 @@ static void mtk_pending_work(struct work_struct *work)
 			dev_close(eth->netdev[i]);
 		}
 	}
+
+	dev_dbg(eth->dev, "[%s][%d] reset done\n", __func__, __LINE__);
+
+	clear_bit_unlock(MTK_RESETTING, &eth->state);
+
 	rtnl_unlock();
 }
 
-static int mtk_cleanup(struct mtk_eth *eth)
+static int mtk_free_dev(struct mtk_eth *eth)
 {
 	int i;
 
 	for (i = 0; i < MTK_MAC_COUNT; i++) {
 		if (!eth->netdev[i])
 			continue;
+		free_netdev(eth->netdev[i]);
+	}
+
+	return 0;
+}
+
+static int mtk_unreg_dev(struct mtk_eth *eth)
+{
+	int i;
 
+	for (i = 0; i < MTK_MAC_COUNT; i++) {
+		if (!eth->netdev[i])
+			continue;
 		unregister_netdev(eth->netdev[i]);
-		free_netdev(eth->netdev[i]);
 	}
+
+	return 0;
+}
+
+static int mtk_cleanup(struct mtk_eth *eth)
+{
+	mtk_unreg_dev(eth);
+	mtk_free_dev(eth);
 	cancel_work_sync(&eth->pending_work);
 
 	return 0;
@@ -1587,6 +1683,9 @@ static int mtk_get_settings(struct net_device *dev,
 	struct mtk_mac *mac = netdev_priv(dev);
 	int err;
 
+	if (unlikely(test_bit(MTK_RESETTING, &mac->hw->state)))
+		return -EBUSY;
+
 	err = phy_read_status(mac->phy_dev);
 	if (err)
 		return -ENODEV;
@@ -1637,6 +1736,9 @@ static int mtk_nway_reset(struct net_device *dev)
 {
 	struct mtk_mac *mac = netdev_priv(dev);
 
+	if (unlikely(test_bit(MTK_RESETTING, &mac->hw->state)))
+		return -EBUSY;
+
 	return genphy_restart_aneg(mac->phy_dev);
 }
 
@@ -1645,6 +1747,9 @@ static u32 mtk_get_link(struct net_device *dev)
 	struct mtk_mac *mac = netdev_priv(dev);
 	int err;
 
+	if (unlikely(test_bit(MTK_RESETTING, &mac->hw->state)))
+		return -EBUSY;
+
 	err = genphy_update_link(mac->phy_dev);
 	if (err)
 		return ethtool_op_get_link(dev);
@@ -1685,6 +1790,9 @@ static void mtk_get_ethtool_stats(struct net_device *dev,
 	unsigned int start;
 	int i;
 
+	if (unlikely(test_bit(MTK_RESETTING, &mac->hw->state)))
+		return;
+
 	if (netif_running(dev) && netif_device_present(dev)) {
 		if (spin_trylock(&hwstats->stats_lock)) {
 			mtk_stats_update_mac(mac);
@@ -1786,16 +1894,7 @@ static int mtk_add_mac(struct mtk_eth *eth, struct device_node *np)
 	eth->netdev[id]->features |= MTK_HW_FEATURES;
 	eth->netdev[id]->ethtool_ops = &mtk_ethtool_ops;
 
-	err = register_netdev(eth->netdev[id]);
-	if (err) {
-		dev_err(eth->dev, "error bringing up device\n");
-		goto free_netdev;
-	}
 	eth->netdev[id]->irq = eth->irq[0];
-	netif_info(eth, probe, eth->netdev[id],
-		   "mediatek frame engine at 0x%08lx, irq %d\n",
-		   eth->netdev[id]->base_addr, eth->irq[0]);
-
 	return 0;
 
 free_netdev:
@@ -1842,12 +1941,6 @@ static int mtk_probe(struct platform_device *pdev)
 		return PTR_ERR(eth->pctl);
 	}
 
-	eth->rstc = devm_reset_control_get(&pdev->dev, "eth");
-	if (IS_ERR(eth->rstc)) {
-		dev_err(&pdev->dev, "no eth reset found\n");
-		return PTR_ERR(eth->rstc);
-	}
-
 	for (i = 0; i < 3; i++) {
 		eth->irq[i] = platform_get_irq(pdev, i);
 		if (eth->irq[i] < 0) {
@@ -1865,11 +1958,6 @@ static int mtk_probe(struct platform_device *pdev)
 		}
 	}
 
-	clk_prepare_enable(eth->clks[MTK_CLK_ETHIF]);
-	clk_prepare_enable(eth->clks[MTK_CLK_ESW]);
-	clk_prepare_enable(eth->clks[MTK_CLK_GP1]);
-	clk_prepare_enable(eth->clks[MTK_CLK_GP2]);
-
 	eth->msg_enable = netif_msg_init(mtk_msg_level, MTK_DEFAULT_MSG_ENABLE);
 	INIT_WORK(&eth->pending_work, mtk_pending_work);
 
@@ -1887,7 +1975,35 @@ static int mtk_probe(struct platform_device *pdev)
 
 		err = mtk_add_mac(eth, mac_np);
 		if (err)
-			goto err_free_dev;
+			goto err_deinit_hw;
+	}
+
+	err = devm_request_irq(eth->dev, eth->irq[1], mtk_handle_irq_tx, 0,
+			       dev_name(eth->dev), eth);
+	if (err)
+		goto err_free_dev;
+
+	err = devm_request_irq(eth->dev, eth->irq[2], mtk_handle_irq_rx, 0,
+			       dev_name(eth->dev), eth);
+	if (err)
+		goto err_free_dev;
+
+	err = mtk_mdio_init(eth);
+	if (err)
+		goto err_free_dev;
+
+	for (i = 0; i < MTK_MAX_DEVS; i++) {
+		if (!eth->netdev[i])
+			continue;
+
+		err = register_netdev(eth->netdev[i]);
+		if (err) {
+			dev_err(eth->dev, "error bringing up device\n");
+			goto err_deinit_mdio;
+		} else
+			netif_info(eth, probe, eth->netdev[i],
+				   "mediatek frame engine at 0x%08lx, irq %d\n",
+				   eth->netdev[i]->base_addr, eth->irq[0]);
 	}
 
 	/* we run 2 devices on the same DMA ring so we need a dummy device
@@ -1903,8 +2019,13 @@ static int mtk_probe(struct platform_device *pdev)
 
 	return 0;
 
+err_deinit_mdio:
+	mtk_mdio_cleanup(eth);
 err_free_dev:
-	mtk_cleanup(eth);
+	mtk_free_dev(eth);
+err_deinit_hw:
+	mtk_hw_deinit(eth);
+
 	return err;
 }
 
@@ -1920,10 +2041,7 @@ static int mtk_remove(struct platform_device *pdev)
 		mtk_stop(eth->netdev[i]);
 	}
 
-	clk_disable_unprepare(eth->clks[MTK_CLK_ETHIF]);
-	clk_disable_unprepare(eth->clks[MTK_CLK_ESW]);
-	clk_disable_unprepare(eth->clks[MTK_CLK_GP1]);
-	clk_disable_unprepare(eth->clks[MTK_CLK_GP2]);
+	mtk_hw_deinit(eth);
 
 	netif_napi_del(&eth->tx_napi);
 	netif_napi_del(&eth->rx_napi);

drivers/net/ethernet/mediatek/mtk_eth_soc.h

@@ -266,6 +266,11 @@
 #define SYSCFG0_GE_MASK		0x3
 #define SYSCFG0_GE_MODE(x, y)	(x << (12 + (y * 2)))
 
+/*ethernet reset control register*/
+#define ETHSYS_RSTCTRL		0x34
+#define RSTCTRL_FE		BIT(6)
+#define RSTCTRL_PPE		BIT(31)
+
 struct mtk_rx_dma {
 	unsigned int rxd1;
 	unsigned int rxd2;
@@ -330,6 +335,11 @@ enum mtk_clks_map {
 	MTK_CLK_MAX
 };
 
+enum mtk_dev_state {
+	MTK_HW_INIT,
+	MTK_RESETTING
+};
+
 /* struct mtk_tx_buf -	This struct holds the pointers to the memory pointed at
  *			by the TX descriptor	s
  * @skb:		The SKB pointer of the packet being sent
@@ -413,12 +423,12 @@ struct mtk_rx_ring {
  * @clks:		clock array for all clocks required
  * @mii_bus:		If there is a bus we need to create an instance for it
  * @pending_work:	The workqueue used to reset the dma ring
+ * @state               Initialization and runtime state of the device.
  */
 
 struct mtk_eth {
 	struct device			*dev;
 	void __iomem			*base;
-	struct reset_control		*rstc;
 	spinlock_t			page_lock;
 	spinlock_t			irq_lock;
 	struct net_device		dummy_dev;
@@ -441,11 +451,13 @@ struct mtk_eth {
 
 	struct mii_bus			*mii_bus;
 	struct work_struct		pending_work;
+	unsigned long			state;
 };
 
 /* struct mtk_mac -	the structure that holds the info about the MACs of the
  *			SoC
  * @id:			The number of the MAC
+ * @ge_mode:            Interface mode kept for setup restoring
  * @of_node:		Our devicetree node
  * @hw:			Backpointer to our main datastruture
  * @hw_stats:		Packet statistics counter
@@ -453,6 +465,7 @@ struct mtk_eth {
  */
 struct mtk_mac {
 	int				id;
+	int				ge_mode;
 	struct device_node		*of_node;
 	struct mtk_eth			*hw;
 	struct mtk_hw_stats		*hw_stats;