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From: Arkadi Sharshevsky <arkadis@mellanox.com>
Date: Mon, 15 Jan 2018 08:59:11 +0100
Subject: mlxsw: core: Add support for reload
Patch-mainline: v4.16-rc1
Git-commit: 24cc68ad6c46f04f0206b41359e7af84e6dbde98
References: bsc#1112374

Add support for hot reload. First, all the driver/core resources are
released but the PCI and devlink instances, then reset is performed
through the PCI interface. Finally the driver performs initialization.

In case of reload failure the driver is left in a partially initialized
state. Special care is taken during the driver removal in order to
properly handle this state.

Signed-off-by: Arkadi Sharshevsky <arkadis@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlxsw/core.c |   73 ++++++++++++++++++++++-------
 drivers/net/ethernet/mellanox/mlxsw/core.h |    5 +
 drivers/net/ethernet/mellanox/mlxsw/i2c.c  |    5 +
 drivers/net/ethernet/mellanox/mlxsw/pci.c  |    5 +
 4 files changed, 65 insertions(+), 23 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlxsw/core.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/core.c
@@ -113,6 +113,7 @@ struct mlxsw_core {
 	struct mlxsw_thermal *thermal;
 	struct mlxsw_core_port *ports;
 	unsigned int max_ports;
+	bool reload_fail;
 	unsigned long driver_priv[0];
 	/* driver_priv has to be always the last item */
 };
@@ -962,7 +963,28 @@ mlxsw_devlink_sb_occ_tc_port_bind_get(st
 						     pool_type, p_cur, p_max);
 }
 
+static int mlxsw_devlink_core_bus_device_reload(struct devlink *devlink)
+{
+	struct mlxsw_core *mlxsw_core = devlink_priv(devlink);
+	const struct mlxsw_bus *mlxsw_bus = mlxsw_core->bus;
+	int err;
+
+	if (!mlxsw_bus->reset)
+		return -EOPNOTSUPP;
+
+	mlxsw_core_bus_device_unregister(mlxsw_core, true);
+	mlxsw_bus->reset(mlxsw_core->bus_priv);
+	err = mlxsw_core_bus_device_register(mlxsw_core->bus_info,
+					     mlxsw_core->bus,
+					     mlxsw_core->bus_priv, true,
+					     devlink);
+	if (err)
+		mlxsw_core->reload_fail = true;
+	return err;
+}
+
 static const struct devlink_ops mlxsw_devlink_ops = {
+	.reload				= mlxsw_devlink_core_bus_device_reload,
 	.port_type_set			= mlxsw_devlink_port_type_set,
 	.port_split			= mlxsw_devlink_port_split,
 	.port_unsplit			= mlxsw_devlink_port_unsplit,
@@ -980,23 +1002,26 @@ static const struct devlink_ops mlxsw_de
 
 int mlxsw_core_bus_device_register(const struct mlxsw_bus_info *mlxsw_bus_info,
 				   const struct mlxsw_bus *mlxsw_bus,
-				   void *bus_priv)
+				   void *bus_priv, bool reload,
+				   struct devlink *devlink)
 {
 	const char *device_kind = mlxsw_bus_info->device_kind;
 	struct mlxsw_core *mlxsw_core;
 	struct mlxsw_driver *mlxsw_driver;
-	struct devlink *devlink;
 	size_t alloc_size;
 	int err;
 
 	mlxsw_driver = mlxsw_core_driver_get(device_kind);
 	if (!mlxsw_driver)
 		return -EINVAL;
-	alloc_size = sizeof(*mlxsw_core) + mlxsw_driver->priv_size;
-	devlink = devlink_alloc(&mlxsw_devlink_ops, alloc_size);
-	if (!devlink) {
-		err = -ENOMEM;
-		goto err_devlink_alloc;
+
+	if (!reload) {
+		alloc_size = sizeof(*mlxsw_core) + mlxsw_driver->priv_size;
+		devlink = devlink_alloc(&mlxsw_devlink_ops, alloc_size);
+		if (!devlink) {
+			err = -ENOMEM;
+			goto err_devlink_alloc;
+		}
 	}
 
 	mlxsw_core = devlink_priv(devlink);
@@ -1012,7 +1037,7 @@ int mlxsw_core_bus_device_register(const
 	if (err)
 		goto err_bus_init;
 
-	if (mlxsw_driver->resources_register) {
+	if (mlxsw_driver->resources_register && !reload) {
 		err = mlxsw_driver->resources_register(mlxsw_core);
 		if (err)
 			goto err_register_resources;
@@ -1038,9 +1063,11 @@ int mlxsw_core_bus_device_register(const
 	if (err)
 		goto err_emad_init;
 
-	err = devlink_register(devlink, mlxsw_bus_info->dev);
-	if (err)
-		goto err_devlink_register;
+	if (!reload) {
+		err = devlink_register(devlink, mlxsw_bus_info->dev);
+		if (err)
+			goto err_devlink_register;
+	}
 
 	err = mlxsw_hwmon_init(mlxsw_core, mlxsw_bus_info, &mlxsw_core->hwmon);
 	if (err)
@@ -1063,7 +1090,8 @@ err_driver_init:
 	mlxsw_thermal_fini(mlxsw_core->thermal);
 err_thermal_init:
 err_hwmon_init:
-	devlink_unregister(devlink);
+	if (!reload)
+		devlink_unregister(devlink);
 err_devlink_register:
 	mlxsw_emad_fini(mlxsw_core);
 err_emad_init:
@@ -1073,29 +1101,40 @@ err_alloc_lag_mapping:
 err_ports_init:
 	mlxsw_bus->fini(bus_priv);
 err_bus_init:
-	devlink_resources_unregister(devlink, NULL);
+	if (!reload)
+		devlink_resources_unregister(devlink, NULL);
 err_register_resources:
-	devlink_free(devlink);
+	if (!reload)
+		devlink_free(devlink);
 err_devlink_alloc:
 	mlxsw_core_driver_put(device_kind);
 	return err;
 }
 EXPORT_SYMBOL(mlxsw_core_bus_device_register);
 
-void mlxsw_core_bus_device_unregister(struct mlxsw_core *mlxsw_core)
+void mlxsw_core_bus_device_unregister(struct mlxsw_core *mlxsw_core,
+				      bool reload)
 {
 	const char *device_kind = mlxsw_core->bus_info->device_kind;
 	struct devlink *devlink = priv_to_devlink(mlxsw_core);
 
+	if (mlxsw_core->reload_fail)
+		goto reload_fail;
+
 	if (mlxsw_core->driver->fini)
 		mlxsw_core->driver->fini(mlxsw_core);
 	mlxsw_thermal_fini(mlxsw_core->thermal);
-	devlink_unregister(devlink);
+	if (!reload)
+		devlink_unregister(devlink);
 	mlxsw_emad_fini(mlxsw_core);
 	kfree(mlxsw_core->lag.mapping);
 	mlxsw_ports_fini(mlxsw_core);
-	devlink_resources_unregister(devlink, NULL);
+	if (!reload)
+		devlink_resources_unregister(devlink, NULL);
 	mlxsw_core->bus->fini(mlxsw_core->bus_priv);
+	if (reload)
+		return;
+reload_fail:
 	devlink_free(devlink);
 	mlxsw_core_driver_put(device_kind);
 }
--- a/drivers/net/ethernet/mellanox/mlxsw/core.h
+++ b/drivers/net/ethernet/mellanox/mlxsw/core.h
@@ -66,8 +66,9 @@ void mlxsw_core_driver_unregister(struct
 
 int mlxsw_core_bus_device_register(const struct mlxsw_bus_info *mlxsw_bus_info,
 				   const struct mlxsw_bus *mlxsw_bus,
-				   void *bus_priv);
-void mlxsw_core_bus_device_unregister(struct mlxsw_core *mlxsw_core);
+				   void *bus_priv, bool reload,
+				   struct devlink *devlink);
+void mlxsw_core_bus_device_unregister(struct mlxsw_core *mlxsw_core, bool reload);
 
 struct mlxsw_tx_info {
 	u8 local_port;
--- a/drivers/net/ethernet/mellanox/mlxsw/i2c.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/i2c.c
@@ -539,7 +539,8 @@ static int mlxsw_i2c_probe(struct i2c_cl
 	mlxsw_i2c->dev = &client->dev;
 
 	err = mlxsw_core_bus_device_register(&mlxsw_i2c->bus_info,
-					     &mlxsw_i2c_bus, mlxsw_i2c);
+					     &mlxsw_i2c_bus, mlxsw_i2c, false,
+					     NULL);
 	if (err) {
 		dev_err(&client->dev, "Fail to register core bus\n");
 		return err;
@@ -557,7 +558,7 @@ static int mlxsw_i2c_remove(struct i2c_c
 {
 	struct mlxsw_i2c *mlxsw_i2c = i2c_get_clientdata(client);
 
-	mlxsw_core_bus_device_unregister(mlxsw_i2c->core);
+	mlxsw_core_bus_device_unregister(mlxsw_i2c->core, false);
 	mutex_destroy(&mlxsw_i2c->cmd.lock);
 
 	return 0;
--- a/drivers/net/ethernet/mellanox/mlxsw/pci.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/pci.c
@@ -1739,7 +1739,8 @@ static int mlxsw_pci_probe(struct pci_de
 	mlxsw_pci->id = id;
 
 	err = mlxsw_core_bus_device_register(&mlxsw_pci->bus_info,
-					     &mlxsw_pci_bus, mlxsw_pci);
+					     &mlxsw_pci_bus, mlxsw_pci, false,
+					     NULL);
 	if (err) {
 		dev_err(&pdev->dev, "cannot register bus device\n");
 		goto err_bus_device_register;
@@ -1767,7 +1768,7 @@ static void mlxsw_pci_remove(struct pci_
 {
 	struct mlxsw_pci *mlxsw_pci = pci_get_drvdata(pdev);
 
-	mlxsw_core_bus_device_unregister(mlxsw_pci->core);
+	mlxsw_core_bus_device_unregister(mlxsw_pci->core, false);
 	mlxsw_pci_free_irq_vectors(mlxsw_pci);
 	iounmap(mlxsw_pci->hw_addr);
 	pci_release_regions(mlxsw_pci->pdev);