net: hibmcge: Add reset supported in this module

Sometimes, if the port doesn't work, we can try to fix it by resetting it.

This patch supports reset triggered by ethtool or FLR of PCIe, For example:
 ethtool --reset eth0 dedicated
 echo 1 > /sys/bus/pci/devices/0000\:83\:00.1/reset

We hope that the reset can be performed only when the port is down,
and the port cannot be up during the reset.
Therefore, the entire reset process is protected by the rtnl lock.

After the reset is complete, the hardware registers are restored
to their default values. Therefore, some rebuild operations are
required to rewrite the user configuration to the registers.

Signed-off-by: Jijie Shao <shaojijie@huawei.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20241216040532.1566229-7-shaojijie@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/hisilicon/hibmcge/Makefile

@@ -6,4 +6,4 @@
 obj-$(CONFIG_HIBMCGE) += hibmcge.o
 
 hibmcge-objs = hbg_main.o hbg_hw.o hbg_mdio.o hbg_irq.o hbg_txrx.o hbg_ethtool.o \
-		hbg_debugfs.o
+		hbg_debugfs.o hbg_err.o

drivers/net/ethernet/hisilicon/hibmcge/hbg_common.h

@@ -4,6 +4,7 @@
 #ifndef __HBG_COMMON_H
 #define __HBG_COMMON_H
 
+#include <linux/ethtool.h>
 #include <linux/netdevice.h>
 #include <linux/pci.h>
 #include "hbg_reg.h"
@@ -33,6 +34,14 @@ enum hbg_tx_state {
 
 enum hbg_nic_state {
 	HBG_NIC_STATE_EVENT_HANDLING = 0,
+	HBG_NIC_STATE_RESETTING,
+	HBG_NIC_STATE_RESET_FAIL,
+};
+
+enum hbg_reset_type {
+	HBG_RESET_TYPE_NONE = 0,
+	HBG_RESET_TYPE_FLR,
+	HBG_RESET_TYPE_FUNCTION,
 };
 
 struct hbg_buffer {
@@ -128,6 +137,11 @@ struct hbg_mac_filter {
 	bool enabled;
 };
 
+/* saved for restore after rest */
+struct hbg_user_def {
+	struct ethtool_pauseparam pause_param;
+};
+
 struct hbg_priv {
 	struct net_device *netdev;
 	struct pci_dev *pdev;
@@ -139,6 +153,8 @@ struct hbg_priv {
 	struct hbg_ring tx_ring;
 	struct hbg_ring rx_ring;
 	struct hbg_mac_filter filter;
+	enum hbg_reset_type reset_type;
+	struct hbg_user_def user_def;
 };
 
 #endif

drivers/net/ethernet/hisilicon/hibmcge/hbg_debugfs.c

@@ -19,6 +19,8 @@ struct hbg_dbg_info {
 	int (*read)(struct seq_file *seq, void *data);
 };
 
+#define state_str_true_false(p, s) str_true_false(test_bit(s, &(p)->state))
+
 static void hbg_dbg_ring(struct hbg_priv *priv, struct hbg_ring *ring,
 			 struct seq_file *s)
 {
@@ -97,11 +99,31 @@ static int hbg_dbg_mac_table(struct seq_file *s, void *unused)
 	return 0;
 }
 
+static const char * const reset_type_str[] = {"None", "FLR", "Function"};
+
+static int hbg_dbg_nic_state(struct seq_file *s, void *unused)
+{
+	struct net_device *netdev = dev_get_drvdata(s->private);
+	struct hbg_priv *priv = netdev_priv(netdev);
+
+	seq_printf(s, "event handling state: %s\n",
+		   state_str_true_false(priv, HBG_NIC_STATE_EVENT_HANDLING));
+	seq_printf(s, "resetting state: %s\n",
+		   state_str_true_false(priv, HBG_NIC_STATE_RESETTING));
+	seq_printf(s, "reset fail state: %s\n",
+		   state_str_true_false(priv, HBG_NIC_STATE_RESET_FAIL));
+	seq_printf(s, "last reset type: %s\n",
+		   reset_type_str[priv->reset_type]);
+
+	return 0;
+}
+
 static const struct hbg_dbg_info hbg_dbg_infos[] = {
 	{ "tx_ring", hbg_dbg_tx_ring },
 	{ "rx_ring", hbg_dbg_rx_ring },
 	{ "irq_info", hbg_dbg_irq_info },
 	{ "mac_table", hbg_dbg_mac_table },
+	{ "nic_state", hbg_dbg_nic_state },
 };
 
 static void hbg_debugfs_uninit(void *data)

drivers/net/ethernet/hisilicon/hibmcge/hbg_err.c

@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright (c) 2024 Hisilicon Limited.
+
+#include <linux/etherdevice.h>
+#include <linux/netdevice.h>
+#include <linux/phy.h>
+#include <linux/rtnetlink.h>
+#include "hbg_common.h"
+#include "hbg_err.h"
+#include "hbg_hw.h"
+
+static void hbg_restore_mac_table(struct hbg_priv *priv)
+{
+	struct hbg_mac_filter *filter = &priv->filter;
+	u64 addr;
+	u32 i;
+
+	for (i = 0; i < filter->table_max_len; i++)
+		if (!is_zero_ether_addr(filter->mac_table[i].addr)) {
+			addr = ether_addr_to_u64(filter->mac_table[i].addr);
+			hbg_hw_set_uc_addr(priv, addr, i);
+		}
+
+	hbg_hw_set_mac_filter_enable(priv, priv->filter.enabled);
+}
+
+static void hbg_restore_user_def_settings(struct hbg_priv *priv)
+{
+	struct ethtool_pauseparam *pause_param = &priv->user_def.pause_param;
+
+	hbg_restore_mac_table(priv);
+	hbg_hw_set_mtu(priv, priv->netdev->mtu);
+	hbg_hw_set_pause_enable(priv, pause_param->tx_pause,
+				pause_param->rx_pause);
+}
+
+int hbg_rebuild(struct hbg_priv *priv)
+{
+	int ret;
+
+	ret = hbg_hw_init(priv);
+	if (ret)
+		return ret;
+
+	hbg_restore_user_def_settings(priv);
+	return 0;
+}
+
+static int hbg_reset_prepare(struct hbg_priv *priv, enum hbg_reset_type type)
+{
+	int ret;
+
+	ASSERT_RTNL();
+
+	if (netif_running(priv->netdev)) {
+		dev_warn(&priv->pdev->dev,
+			 "failed to reset because port is up\n");
+		return -EBUSY;
+	}
+
+	priv->reset_type = type;
+	set_bit(HBG_NIC_STATE_RESETTING, &priv->state);
+	clear_bit(HBG_NIC_STATE_RESET_FAIL, &priv->state);
+	ret = hbg_hw_event_notify(priv, HBG_HW_EVENT_RESET);
+	if (ret) {
+		set_bit(HBG_NIC_STATE_RESET_FAIL, &priv->state);
+		clear_bit(HBG_NIC_STATE_RESETTING, &priv->state);
+	}
+
+	return ret;
+}
+
+static int hbg_reset_done(struct hbg_priv *priv, enum hbg_reset_type type)
+{
+	int ret;
+
+	if (!test_bit(HBG_NIC_STATE_RESETTING, &priv->state) ||
+	    type != priv->reset_type)
+		return 0;
+
+	ASSERT_RTNL();
+
+	clear_bit(HBG_NIC_STATE_RESETTING, &priv->state);
+	ret = hbg_rebuild(priv);
+	if (ret) {
+		set_bit(HBG_NIC_STATE_RESET_FAIL, &priv->state);
+		dev_err(&priv->pdev->dev, "failed to rebuild after reset\n");
+		return ret;
+	}
+
+	dev_info(&priv->pdev->dev, "reset done\n");
+	return ret;
+}
+
+/* must be protected by rtnl lock */
+int hbg_reset(struct hbg_priv *priv)
+{
+	int ret;
+
+	ASSERT_RTNL();
+	ret = hbg_reset_prepare(priv, HBG_RESET_TYPE_FUNCTION);
+	if (ret)
+		return ret;
+
+	return hbg_reset_done(priv, HBG_RESET_TYPE_FUNCTION);
+}
+
+static void hbg_pci_err_reset_prepare(struct pci_dev *pdev)
+{
+	struct net_device *netdev = pci_get_drvdata(pdev);
+	struct hbg_priv *priv = netdev_priv(netdev);
+
+	rtnl_lock();
+	hbg_reset_prepare(priv, HBG_RESET_TYPE_FLR);
+}
+
+static void hbg_pci_err_reset_done(struct pci_dev *pdev)
+{
+	struct net_device *netdev = pci_get_drvdata(pdev);
+	struct hbg_priv *priv = netdev_priv(netdev);
+
+	hbg_reset_done(priv, HBG_RESET_TYPE_FLR);
+	rtnl_unlock();
+}
+
+static const struct pci_error_handlers hbg_pci_err_handler = {
+	.reset_prepare = hbg_pci_err_reset_prepare,
+	.reset_done = hbg_pci_err_reset_done,
+};
+
+void hbg_set_pci_err_handler(struct pci_driver *pdrv)
+{
+	pdrv->err_handler = &hbg_pci_err_handler;
+}

drivers/net/ethernet/hisilicon/hibmcge/hbg_err.h

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/* Copyright (c) 2024 Hisilicon Limited. */
+
+#ifndef __HBG_ERR_H
+#define __HBG_ERR_H
+
+#include <linux/pci.h>
+
+void hbg_set_pci_err_handler(struct pci_driver *pdrv);
+int hbg_reset(struct hbg_priv *priv);
+int hbg_rebuild(struct hbg_priv *priv);
+
+#endif

drivers/net/ethernet/hisilicon/hibmcge/hbg_ethtool.c

@@ -3,7 +3,9 @@
 
 #include <linux/ethtool.h>
 #include <linux/phy.h>
+#include <linux/rtnetlink.h>
 #include "hbg_common.h"
+#include "hbg_err.h"
 #include "hbg_ethtool.h"
 #include "hbg_hw.h"
 
@@ -163,9 +165,21 @@ static int hbg_ethtool_set_pauseparam(struct net_device *net_dev,
 	if (!param->autoneg)
 		hbg_hw_set_pause_enable(priv, param->tx_pause, param->rx_pause);
 
+	priv->user_def.pause_param = *param;
 	return 0;
 }
 
+static int hbg_ethtool_reset(struct net_device *netdev, u32 *flags)
+{
+	struct hbg_priv *priv = netdev_priv(netdev);
+
+	if (*flags != ETH_RESET_DEDICATED)
+		return -EOPNOTSUPP;
+
+	*flags = 0;
+	return hbg_reset(priv);
+}
+
 static const struct ethtool_ops hbg_ethtool_ops = {
 	.get_link		= ethtool_op_get_link,
 	.get_link_ksettings	= phy_ethtool_get_link_ksettings,
@@ -174,6 +188,7 @@ static const struct ethtool_ops hbg_ethtool_ops = {
 	.get_regs		= hbg_ethtool_get_regs,
 	.get_pauseparam         = hbg_ethtool_get_pauseparam,
 	.set_pauseparam         = hbg_ethtool_set_pauseparam,
+	.reset			= hbg_ethtool_reset,
 };
 
 void hbg_ethtool_set_ops(struct net_device *netdev)

drivers/net/ethernet/hisilicon/hibmcge/hbg_hw.c

@@ -3,6 +3,7 @@
 
 #include <linux/etherdevice.h>
 #include <linux/ethtool.h>
+#include <linux/if_vlan.h>
 #include <linux/iopoll.h>
 #include <linux/minmax.h>
 #include "hbg_common.h"
@@ -167,8 +168,13 @@ static void hbg_hw_set_mac_max_frame_len(struct hbg_priv *priv,
 
 void hbg_hw_set_mtu(struct hbg_priv *priv, u16 mtu)
 {
-	hbg_hw_set_pcu_max_frame_len(priv, mtu);
-	hbg_hw_set_mac_max_frame_len(priv, mtu);
+	u32 frame_len;
+
+	frame_len = mtu + VLAN_HLEN * priv->dev_specs.vlan_layers +
+		    ETH_HLEN + ETH_FCS_LEN;
+
+	hbg_hw_set_pcu_max_frame_len(priv, frame_len);
+	hbg_hw_set_mac_max_frame_len(priv, frame_len);
 }
 
 void hbg_hw_mac_enable(struct hbg_priv *priv, u32 enable)