text: #include <linux/export.h>
  #include <linux/kref.h>
  #include <linux/list.h>
  #include <linux/mutex.h>
  #include <linux/phylink.h>
  #include <linux/rtnetlink.h>
  #include <linux/slab.h>
  
  #include "sfp.h"
  
  struct sfp_bus {
  	struct kref kref;
  	struct list_head node;
  	struct device_node *device_node;
  
  	const struct sfp_socket_ops *socket_ops;
  	struct device *sfp_dev;
  	struct sfp *sfp;
  
  	const struct sfp_upstream_ops *upstream_ops;
  	void *upstream;
  	struct net_device *netdev;
  	struct phy_device *phydev;
  
  	bool registered;
  	bool started;
  };
  
  
  int sfp_parse_port(struct sfp_bus *bus, const struct sfp_eeprom_id *id,
  		   unsigned long *support)
  {
  	int port;
  
  	/* port is the physical connector, set this from the connector field. */
  	switch (id->base.connector) {
  	case SFP_CONNECTOR_SC:
  	case SFP_CONNECTOR_FIBERJACK:
  	case SFP_CONNECTOR_LC:
  	case SFP_CONNECTOR_MT_RJ:
  	case SFP_CONNECTOR_MU:
  	case SFP_CONNECTOR_OPTICAL_PIGTAIL:
  		if (support)
  			phylink_set(support, FIBRE);
  		port = PORT_FIBRE;
  		break;
  
  	case SFP_CONNECTOR_RJ45:
  		if (support)
  			phylink_set(support, TP);
  		port = PORT_TP;
  		break;
  
  	case SFP_CONNECTOR_UNSPEC:
  		if (id->base.e1000_base_t) {
  			if (support)
  				phylink_set(support, TP);
  			port = PORT_TP;
  			break;
  		}
  		/* fallthrough */
  	case SFP_CONNECTOR_SG: /* guess */
  	case SFP_CONNECTOR_MPO_1X12:
  	case SFP_CONNECTOR_MPO_2X16:
  	case SFP_CONNECTOR_HSSDC_II:
  	case SFP_CONNECTOR_COPPER_PIGTAIL:
  	case SFP_CONNECTOR_NOSEPARATE:
  	case SFP_CONNECTOR_MXC_2X16:
  		port = PORT_OTHER;
  		break;
  	default:
  		dev_warn(bus->sfp_dev, "SFP: unknown connector id 0x%02x\n",
  			 id->base.connector);
  		port = PORT_OTHER;
  		break;
  	}
  
  	return port;
  }
  EXPORT_SYMBOL_GPL(sfp_parse_port);
  
  phy_interface_t sfp_parse_interface(struct sfp_bus *bus,
  				    const struct sfp_eeprom_id *id)
  {
  	phy_interface_t iface;
  
  	/* Setting the serdes link mode is guesswork: there's no field in
  	 * the EEPROM which indicates what mode should be used.
  	 *
  	 * If the module wants 64b66b, then it must be >= 10G.
  	 *
  	 * If it's a gigabit-only fiber module, it probably does not have
  	 * a PHY, so switch to 802.3z negotiation mode. Otherwise, switch
  	 * to SGMII mode (which is required to support non-gigabit speeds).
  	 */
  	switch (id->base.encoding) {
  	case SFP_ENCODING_8472_64B66B:
  		iface = PHY_INTERFACE_MODE_10GKR;
  		break;
  
  	case SFP_ENCODING_8B10B:
  		if (!id->base.e1000_base_t &&
  		    !id->base.e100_base_lx &&
  		    !id->base.e100_base_fx)
  			iface = PHY_INTERFACE_MODE_1000BASEX;
  		else
  			iface = PHY_INTERFACE_MODE_SGMII;
  		break;
  
  	default:
  		iface = PHY_INTERFACE_MODE_NA;
  		dev_err(bus->sfp_dev,
  			"SFP module encoding does not support 8b10b nor 64b66b\n");
  		break;
  	}
  
  	return iface;
  }
  EXPORT_SYMBOL_GPL(sfp_parse_interface);
  
  void sfp_parse_support(struct sfp_bus *bus, const struct sfp_eeprom_id *id,
  		       unsigned long *support)
  {
  	phylink_set(support, Autoneg);
  	phylink_set(support, Pause);
  	phylink_set(support, Asym_Pause);
  
  	/* Set ethtool support from the compliance fields. */
  	if (id->base.e10g_base_sr)
  		phylink_set(support, 10000baseSR_Full);
  	if (id->base.e10g_base_lr)
  		phylink_set(support, 10000baseLR_Full);
  	if (id->base.e10g_base_lrm)
  		phylink_set(support, 10000baseLRM_Full);
  	if (id->base.e10g_base_er)
  		phylink_set(support, 10000baseER_Full);
  	if (id->base.e1000_base_sx ||
  	    id->base.e1000_base_lx ||
  	    id->base.e1000_base_cx)
  		phylink_set(support, 1000baseX_Full);
  	if (id->base.e1000_base_t) {
  		phylink_set(support, 1000baseT_Half);
  		phylink_set(support, 1000baseT_Full);
  	}
  
  	switch (id->base.extended_cc) {
  	case 0x00: /* Unspecified */
  		break;
  	case 0x02: /* 100Gbase-SR4 or 25Gbase-SR */
  		phylink_set(support, 100000baseSR4_Full);
  		phylink_set(support, 25000baseSR_Full);
  		break;
  	case 0x03: /* 100Gbase-LR4 or 25Gbase-LR */
  	case 0x04: /* 100Gbase-ER4 or 25Gbase-ER */
  		phylink_set(support, 100000baseLR4_ER4_Full);
  		break;
  	case 0x0b: /* 100Gbase-CR4 or 25Gbase-CR CA-L */
  	case 0x0c: /* 25Gbase-CR CA-S */
  	case 0x0d: /* 25Gbase-CR CA-N */
  		phylink_set(support, 100000baseCR4_Full);
  		phylink_set(support, 25000baseCR_Full);
  		break;
  	default:
  		dev_warn(bus->sfp_dev,
  			 "Unknown/unsupported extended compliance code: 0x%02x\n",
  			 id->base.extended_cc);
  		break;
  	}
  
  	/* For fibre channel SFP, derive possible BaseX modes */
  	if (id->base.fc_speed_100 ||
  	    id->base.fc_speed_200 ||
  	    id->base.fc_speed_400) {
  		if (id->base.br_nominal >= 31)
  			phylink_set(support, 2500baseX_Full);
  		if (id->base.br_nominal >= 12)
  			phylink_set(support, 1000baseX_Full);
  	}
  
  	switch (id->base.connector) {
  	case SFP_CONNECTOR_SC:
  	case SFP_CONNECTOR_FIBERJACK:
  	case SFP_CONNECTOR_LC:
  	case SFP_CONNECTOR_MT_RJ:
  	case SFP_CONNECTOR_MU:
  	case SFP_CONNECTOR_OPTICAL_PIGTAIL:
  		break;
  
  	case SFP_CONNECTOR_UNSPEC:
  		if (id->base.e1000_base_t)
  			break;
  
  	case SFP_CONNECTOR_SG: /* guess */
  	case SFP_CONNECTOR_MPO_1X12:
  	case SFP_CONNECTOR_MPO_2X16:
  	case SFP_CONNECTOR_HSSDC_II:
  	case SFP_CONNECTOR_COPPER_PIGTAIL:
  	case SFP_CONNECTOR_NOSEPARATE:
  	case SFP_CONNECTOR_MXC_2X16:
  	default:
  		/* a guess at the supported link modes */
  		dev_warn(bus->sfp_dev,
  			 "Guessing link modes, please report...\n");
  		phylink_set(support, 1000baseT_Half);
  		phylink_set(support, 1000baseT_Full);
  		break;
  	}
  }
  EXPORT_SYMBOL_GPL(sfp_parse_support);
  
  
  static LIST_HEAD(sfp_buses);
  static DEFINE_MUTEX(sfp_mutex);
  
  static const struct sfp_upstream_ops *sfp_get_upstream_ops(struct sfp_bus *bus)
  {
  	return bus->registered ? bus->upstream_ops : NULL;
  }
  
  static struct sfp_bus *sfp_bus_get(struct device_node *np)
  {
  	struct sfp_bus *sfp, *new, *found = NULL;
  
  	new = kzalloc(sizeof(*new), GFP_KERNEL);
  
  	mutex_lock(&sfp_mutex);
  
  	list_for_each_entry(sfp, &sfp_buses, node) {
  		if (sfp->device_node == np) {
  			kref_get(&sfp->kref);
  			found = sfp;
  			break;
  		}
  	}
  
  	if (!found && new) {
  		kref_init(&new->kref);
  		new->device_node = np;
  		list_add(&new->node, &sfp_buses);
  		found = new;
  		new = NULL;
  	}
  
  	mutex_unlock(&sfp_mutex);
  
  	kfree(new);
  
  	return found;
  }
  
  static void sfp_bus_release(struct kref *kref) __releases(sfp_mutex)
  {
  	struct sfp_bus *bus = container_of(kref, struct sfp_bus, kref);
  
  	list_del(&bus->node);
  	mutex_unlock(&sfp_mutex);
  	kfree(bus);
  }
  
  static void sfp_bus_put(struct sfp_bus *bus)
  {
  	kref_put_mutex(&bus->kref, sfp_bus_release, &sfp_mutex);
  }
  
  static int sfp_register_bus(struct sfp_bus *bus)
  {
  	const struct sfp_upstream_ops *ops = bus->upstream_ops;
  	int ret;
  
  	if (ops) {
  		if (ops->link_down)
  			ops->link_down(bus->upstream);
  		if (ops->connect_phy && bus->phydev) {
  			ret = ops->connect_phy(bus->upstream, bus->phydev);
  			if (ret)
  				return ret;
  		}
  	}
  	bus->socket_ops->attach(bus->sfp);
  	if (bus->started)
  		bus->socket_ops->start(bus->sfp);
  	bus->registered = true;
  	return 0;
  }
  
  static void sfp_unregister_bus(struct sfp_bus *bus)
  {
  	const struct sfp_upstream_ops *ops = bus->upstream_ops;
  
  	if (bus->registered) {
  		if (bus->started)
  			bus->socket_ops->stop(bus->sfp);
  		bus->socket_ops->detach(bus->sfp);
  		if (bus->phydev && ops && ops->disconnect_phy)
  			ops->disconnect_phy(bus->upstream);
  	}
  	bus->registered = false;
  }
  
  
  int sfp_get_module_info(struct sfp_bus *bus, struct ethtool_modinfo *modinfo)
  {
  	if (!bus->registered)
  		return -ENOIOCTLCMD;
  	return bus->socket_ops->module_info(bus->sfp, modinfo);
  }
  EXPORT_SYMBOL_GPL(sfp_get_module_info);
  
  int sfp_get_module_eeprom(struct sfp_bus *bus, struct ethtool_eeprom *ee,
  	u8 *data)
  {
  	if (!bus->registered)
  		return -ENOIOCTLCMD;
  	return bus->socket_ops->module_eeprom(bus->sfp, ee, data);
  }
  EXPORT_SYMBOL_GPL(sfp_get_module_eeprom);
  
  void sfp_upstream_start(struct sfp_bus *bus)
  {
  	if (bus->registered)
  		bus->socket_ops->start(bus->sfp);
  	bus->started = true;
  }
  EXPORT_SYMBOL_GPL(sfp_upstream_start);
  
  void sfp_upstream_stop(struct sfp_bus *bus)
  {
  	if (bus->registered)
  		bus->socket_ops->stop(bus->sfp);
  	bus->started = false;
  }
  EXPORT_SYMBOL_GPL(sfp_upstream_stop);
  
  struct sfp_bus *sfp_register_upstream(struct device_node *np,
  	struct net_device *ndev, void *upstream,
  	const struct sfp_upstream_ops *ops)
  {
  	struct sfp_bus *bus = sfp_bus_get(np);
  	int ret = 0;
  
  	if (bus) {
  		rtnl_lock();
  		bus->upstream_ops = ops;
  		bus->upstream = upstream;
  		bus->netdev = ndev;
  
  		if (bus->sfp)
  			ret = sfp_register_bus(bus);
  		rtnl_unlock();
  	}
  
  	if (ret) {
  		sfp_bus_put(bus);
  		bus = NULL;
  	}
  
  	return bus;
  }
  EXPORT_SYMBOL_GPL(sfp_register_upstream);
  
  void sfp_unregister_upstream(struct sfp_bus *bus)
  {
  	rtnl_lock();
  	if (bus->sfp)
  		sfp_unregister_bus(bus);
  	bus->upstream = NULL;
  	bus->netdev = NULL;
  	rtnl_unlock();
  
  	sfp_bus_put(bus);
  }
  EXPORT_SYMBOL_GPL(sfp_unregister_upstream);
  
  
  /* Socket driver entry points */
  int sfp_add_phy(struct sfp_bus *bus, struct phy_device *phydev)
  {
  	const struct sfp_upstream_ops *ops = sfp_get_upstream_ops(bus);
  	int ret = 0;
  
  	if (ops && ops->connect_phy)
  		ret = ops->connect_phy(bus->upstream, phydev);
  
  	if (ret == 0)
  		bus->phydev = phydev;
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(sfp_add_phy);
  
  void sfp_remove_phy(struct sfp_bus *bus)
  {
  	const struct sfp_upstream_ops *ops = sfp_get_upstream_ops(bus);
  
  	if (ops && ops->disconnect_phy)
  		ops->disconnect_phy(bus->upstream);
  	bus->phydev = NULL;
  }
  EXPORT_SYMBOL_GPL(sfp_remove_phy);
  
  
  void sfp_link_up(struct sfp_bus *bus)
  {
  	const struct sfp_upstream_ops *ops = sfp_get_upstream_ops(bus);
  
  	if (ops && ops->link_up)
  		ops->link_up(bus->upstream);
  }
  EXPORT_SYMBOL_GPL(sfp_link_up);
  
  void sfp_link_down(struct sfp_bus *bus)
  {
  	const struct sfp_upstream_ops *ops = sfp_get_upstream_ops(bus);
  
  	if (ops && ops->link_down)
  		ops->link_down(bus->upstream);
  }
  EXPORT_SYMBOL_GPL(sfp_link_down);
  
  int sfp_module_insert(struct sfp_bus *bus, const struct sfp_eeprom_id *id)
  {
  	const struct sfp_upstream_ops *ops = sfp_get_upstream_ops(bus);
  	int ret = 0;
  
  	if (ops && ops->module_insert)
  		ret = ops->module_insert(bus->upstream, id);
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(sfp_module_insert);
  
  void sfp_module_remove(struct sfp_bus *bus)
  {
  	const struct sfp_upstream_ops *ops = sfp_get_upstream_ops(bus);
  
  	if (ops && ops->module_remove)
  		ops->module_remove(bus->upstream);
  }
  EXPORT_SYMBOL_GPL(sfp_module_remove);
  
  struct sfp_bus *sfp_register_socket(struct device *dev, struct sfp *sfp,
  				    const struct sfp_socket_ops *ops)
  {
  	struct sfp_bus *bus = sfp_bus_get(dev->of_node);
  	int ret = 0;
  
  	if (bus) {
  		rtnl_lock();
  		bus->sfp_dev = dev;
  		bus->sfp = sfp;
  		bus->socket_ops = ops;
  
  		if (bus->netdev)
  			ret = sfp_register_bus(bus);
  		rtnl_unlock();
  	}
  
  	if (ret) {
  		sfp_bus_put(bus);
  		bus = NULL;
  	}
  
  	return bus;
  }
  EXPORT_SYMBOL_GPL(sfp_register_socket);
  
  void sfp_unregister_socket(struct sfp_bus *bus)
  {
  	rtnl_lock();
  	if (bus->netdev)
  		sfp_unregister_bus(bus);
  	bus->sfp_dev = NULL;
  	bus->sfp = NULL;
  	bus->socket_ops = NULL;
  	rtnl_unlock();
  
  	sfp_bus_put(bus);
  }
  EXPORT_SYMBOL_GPL(sfp_unregister_socket);
  