mlxsw: minimal: Add ethtool support

The minimal driver is chip independent and uses I2C bus for chip access.
Its purpose is to support chassis management on systems equipped with
Mellanox switch ASICs. For example from BMC (Board Management
Controller) device.

Expose a dummy netdev for each front panel port and implement basic
ethtool operations to obtain QSFP/SFP module info through ethtool.
Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/minimal.c

 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
-/* Copyright (c) 2016-2018 Mellanox Technologies. All rights reserved */
+/* Copyright (c) 2016-2019 Mellanox Technologies. All rights reserved */
 
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/ethtool.h>
 #include <linux/i2c.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -8,15 +11,332 @@
 #include <linux/types.h>
 
 #include "core.h"
+#include "core_env.h"
 #include "i2c.h"
 
 static const char mlxsw_m_driver_name[] = "mlxsw_minimal";
 
+struct mlxsw_m_port;
+
+struct mlxsw_m {
+	struct mlxsw_m_port **ports;
+	int *module_to_port;
+	struct mlxsw_core *core;
+	const struct mlxsw_bus_info *bus_info;
+	u8 base_mac[ETH_ALEN];
+	u8 max_ports;
+};
+
+struct mlxsw_m_port {
+	struct net_device *dev;
+	struct mlxsw_m *mlxsw_m;
+	u8 local_port;
+	u8 module;
+};
+
+static int mlxsw_m_port_dummy_open_stop(struct net_device *dev)
+{
+	return 0;
+}
+
+static int
+mlxsw_m_port_get_phys_port_name(struct net_device *dev, char *name, size_t len)
+{
+	struct mlxsw_m_port *mlxsw_m_port = netdev_priv(dev);
+	struct mlxsw_core *core = mlxsw_m_port->mlxsw_m->core;
+	u8 local_port = mlxsw_m_port->local_port;
+
+	return mlxsw_core_port_get_phys_port_name(core, local_port, name, len);
+}
+
+static int mlxsw_m_port_get_port_parent_id(struct net_device *dev,
+					   struct netdev_phys_item_id *ppid)
+{
+	struct mlxsw_m_port *mlxsw_m_port = netdev_priv(dev);
+	struct mlxsw_m *mlxsw_m = mlxsw_m_port->mlxsw_m;
+
+	ppid->id_len = sizeof(mlxsw_m->base_mac);
+	memcpy(&ppid->id, &mlxsw_m->base_mac, ppid->id_len);
+
+	return 0;
+}
+
+static const struct net_device_ops mlxsw_m_port_netdev_ops = {
+	.ndo_open		= mlxsw_m_port_dummy_open_stop,
+	.ndo_stop		= mlxsw_m_port_dummy_open_stop,
+	.ndo_get_phys_port_name	= mlxsw_m_port_get_phys_port_name,
+	.ndo_get_port_parent_id	= mlxsw_m_port_get_port_parent_id,
+};
+
+static int mlxsw_m_get_module_info(struct net_device *netdev,
+				   struct ethtool_modinfo *modinfo)
+{
+	struct mlxsw_m_port *mlxsw_m_port = netdev_priv(netdev);
+	struct mlxsw_core *core = mlxsw_m_port->mlxsw_m->core;
+
+	return mlxsw_env_get_module_info(core, mlxsw_m_port->module, modinfo);
+}
+
+static int
+mlxsw_m_get_module_eeprom(struct net_device *netdev, struct ethtool_eeprom *ee,
+			  u8 *data)
+{
+	struct mlxsw_m_port *mlxsw_m_port = netdev_priv(netdev);
+	struct mlxsw_core *core = mlxsw_m_port->mlxsw_m->core;
+
+	return mlxsw_env_get_module_eeprom(netdev, core, mlxsw_m_port->module,
+					   ee, data);
+}
+
+static const struct ethtool_ops mlxsw_m_port_ethtool_ops = {
+	.get_module_info	= mlxsw_m_get_module_info,
+	.get_module_eeprom	= mlxsw_m_get_module_eeprom,
+};
+
+static int
+mlxsw_m_port_module_info_get(struct mlxsw_m *mlxsw_m, u8 local_port,
+			     u8 *p_module, u8 *p_width)
+{
+	char pmlp_pl[MLXSW_REG_PMLP_LEN];
+	int err;
+
+	mlxsw_reg_pmlp_pack(pmlp_pl, local_port);
+	err = mlxsw_reg_query(mlxsw_m->core, MLXSW_REG(pmlp), pmlp_pl);
+	if (err)
+		return err;
+	*p_module = mlxsw_reg_pmlp_module_get(pmlp_pl, 0);
+	*p_width = mlxsw_reg_pmlp_width_get(pmlp_pl);
+
+	return 0;
+}
+
+static int
+mlxsw_m_port_dev_addr_get(struct mlxsw_m_port *mlxsw_m_port)
+{
+	struct mlxsw_m *mlxsw_m = mlxsw_m_port->mlxsw_m;
+	struct net_device *dev = mlxsw_m_port->dev;
+	char ppad_pl[MLXSW_REG_PPAD_LEN];
+	int err;
+
+	mlxsw_reg_ppad_pack(ppad_pl, false, 0);
+	err = mlxsw_reg_query(mlxsw_m->core, MLXSW_REG(ppad), ppad_pl);
+	if (err)
+		return err;
+	mlxsw_reg_ppad_mac_memcpy_from(ppad_pl, dev->dev_addr);
+	/* The last byte value in base mac address is guaranteed
+	 * to be such it does not overflow when adding local_port
+	 * value.
+	 */
+	dev->dev_addr[ETH_ALEN - 1] += mlxsw_m_port->module + 1;
+	return 0;
+}
+
+static int
+mlxsw_m_port_create(struct mlxsw_m *mlxsw_m, u8 local_port, u8 module)
+{
+	struct mlxsw_m_port *mlxsw_m_port;
+	struct net_device *dev;
+	int err;
+
+	err = mlxsw_core_port_init(mlxsw_m->core, local_port);
+	if (err) {
+		dev_err(mlxsw_m->bus_info->dev, "Port %d: Failed to init core port\n",
+			local_port);
+		return err;
+	}
+
+	dev = alloc_etherdev(sizeof(struct mlxsw_m_port));
+	if (!dev) {
+		err = -ENOMEM;
+		goto err_alloc_etherdev;
+	}
+
+	SET_NETDEV_DEV(dev, mlxsw_m->bus_info->dev);
+	mlxsw_m_port = netdev_priv(dev);
+	mlxsw_m_port->dev = dev;
+	mlxsw_m_port->mlxsw_m = mlxsw_m;
+	mlxsw_m_port->local_port = local_port;
+	mlxsw_m_port->module = module;
+
+	dev->netdev_ops = &mlxsw_m_port_netdev_ops;
+	dev->ethtool_ops = &mlxsw_m_port_ethtool_ops;
+
+	err = mlxsw_m_port_dev_addr_get(mlxsw_m_port);
+	if (err) {
+		dev_err(mlxsw_m->bus_info->dev, "Port %d: Unable to get port mac address\n",
+			mlxsw_m_port->local_port);
+		goto err_dev_addr_get;
+	}
+
+	netif_carrier_off(dev);
+	mlxsw_m->ports[local_port] = mlxsw_m_port;
+	err = register_netdev(dev);
+	if (err) {
+		dev_err(mlxsw_m->bus_info->dev, "Port %d: Failed to register netdev\n",
+			mlxsw_m_port->local_port);
+		goto err_register_netdev;
+	}
+
+	mlxsw_core_port_eth_set(mlxsw_m->core, mlxsw_m_port->local_port,
+				mlxsw_m_port, dev, module + 1, false, 0);
+
+	return 0;
+
+err_register_netdev:
+	mlxsw_m->ports[local_port] = NULL;
+	free_netdev(dev);
+err_dev_addr_get:
+err_alloc_etherdev:
+	mlxsw_core_port_fini(mlxsw_m->core, local_port);
+	return err;
+}
+
+static void mlxsw_m_port_remove(struct mlxsw_m *mlxsw_m, u8 local_port)
+{
+	struct mlxsw_m_port *mlxsw_m_port = mlxsw_m->ports[local_port];
+
+	mlxsw_core_port_clear(mlxsw_m->core, local_port, mlxsw_m);
+	unregister_netdev(mlxsw_m_port->dev); /* This calls ndo_stop */
+	mlxsw_m->ports[local_port] = NULL;
+	free_netdev(mlxsw_m_port->dev);
+	mlxsw_core_port_fini(mlxsw_m->core, local_port);
+}
+
+static int mlxsw_m_port_module_map(struct mlxsw_m *mlxsw_m, u8 local_port,
+				   u8 *last_module)
+{
+	u8 module, width;
+	int err;
+
+	/* Fill out to local port mapping array */
+	err = mlxsw_m_port_module_info_get(mlxsw_m, local_port, &module,
+					   &width);
+	if (err)
+		return err;
+
+	if (!width)
+		return 0;
+	/* Skip, if port belongs to the cluster */
+	if (module == *last_module)
+		return 0;
+	*last_module = module;
+	mlxsw_m->module_to_port[module] = ++mlxsw_m->max_ports;
+
+	return 0;
+}
+
+static void mlxsw_m_port_module_unmap(struct mlxsw_m *mlxsw_m, u8 module)
+{
+	mlxsw_m->module_to_port[module] = -1;
+}
+
+static int mlxsw_m_ports_create(struct mlxsw_m *mlxsw_m)
+{
+	unsigned int max_ports = mlxsw_core_max_ports(mlxsw_m->core);
+	u8 last_module = max_ports;
+	int i;
+	int err;
+
+	mlxsw_m->ports = kcalloc(max_ports, sizeof(*mlxsw_m->ports),
+				 GFP_KERNEL);
+	if (!mlxsw_m->ports)
+		return -ENOMEM;
+
+	mlxsw_m->module_to_port = kmalloc_array(max_ports, sizeof(int),
+						GFP_KERNEL);
+	if (!mlxsw_m->module_to_port) {
+		err = -ENOMEM;
+		goto err_module_to_port_alloc;
+	}
+
+	/* Invalidate the entries of module to local port mapping array */
+	for (i = 0; i < max_ports; i++)
+		mlxsw_m->module_to_port[i] = -1;
+
+	/* Fill out module to local port mapping array */
+	for (i = 1; i < max_ports; i++) {
+		err = mlxsw_m_port_module_map(mlxsw_m, i, &last_module);
+		if (err)
+			goto err_module_to_port_map;
+	}
+
+	/* Create port objects for each valid entry */
+	for (i = 0; i < mlxsw_m->max_ports; i++) {
+		if (mlxsw_m->module_to_port[i] > 0) {
+			err = mlxsw_m_port_create(mlxsw_m,
+						  mlxsw_m->module_to_port[i],
+						  i);
+			if (err)
+				goto err_module_to_port_create;
+		}
+	}
+
+	return 0;
+
+err_module_to_port_create:
+	for (i--; i >= 0; i--) {
+		if (mlxsw_m->module_to_port[i] > 0)
+			mlxsw_m_port_remove(mlxsw_m,
+					    mlxsw_m->module_to_port[i]);
+	}
+	i = max_ports;
+err_module_to_port_map:
+	for (i--; i > 0; i--)
+		mlxsw_m_port_module_unmap(mlxsw_m, i);
+	kfree(mlxsw_m->module_to_port);
+err_module_to_port_alloc:
+	kfree(mlxsw_m->ports);
+	return err;
+}
+
+static void mlxsw_m_ports_remove(struct mlxsw_m *mlxsw_m)
+{
+	int i;
+
+	for (i = 0; i < mlxsw_m->max_ports; i++) {
+		if (mlxsw_m->module_to_port[i] > 0) {
+			mlxsw_m_port_remove(mlxsw_m,
+					    mlxsw_m->module_to_port[i]);
+			mlxsw_m_port_module_unmap(mlxsw_m, i);
+		}
+	}
+
+	kfree(mlxsw_m->module_to_port);
+	kfree(mlxsw_m->ports);
+}
+
+static int mlxsw_m_init(struct mlxsw_core *mlxsw_core,
+			const struct mlxsw_bus_info *mlxsw_bus_info)
+{
+	struct mlxsw_m *mlxsw_m = mlxsw_core_driver_priv(mlxsw_core);
+	int err;
+
+	mlxsw_m->core = mlxsw_core;
+	mlxsw_m->bus_info = mlxsw_bus_info;
+
+	err = mlxsw_m_ports_create(mlxsw_m);
+	if (err) {
+		dev_err(mlxsw_m->bus_info->dev, "Failed to create ports\n");
+		return err;
+	}
+
+	return 0;
+}
+
+static void mlxsw_m_fini(struct mlxsw_core *mlxsw_core)
+{
+	struct mlxsw_m *mlxsw_m = mlxsw_core_driver_priv(mlxsw_core);
+
+	mlxsw_m_ports_remove(mlxsw_m);
+}
+
 static const struct mlxsw_config_profile mlxsw_m_config_profile;
 
 static struct mlxsw_driver mlxsw_m_driver = {
 	.kind		= mlxsw_m_driver_name,
-	.priv_size	= 1,
+	.priv_size	= sizeof(struct mlxsw_m),
+	.init		= mlxsw_m_init,
+	.fini		= mlxsw_m_fini,
 	.profile	= &mlxsw_m_config_profile,
 };