#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 - internal representation of a sfp bus
 */
struct sfp_bus {
	/* private: */
	struct kref kref;
	struct list_head node;
	struct fwnode_handle *fwnode;

	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;
};

/**
 * sfp_parse_port() - Parse the EEPROM base ID, setting the port type
 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
 * @id: a pointer to the module's &struct sfp_eeprom_id
 * @support: optional pointer to an array of unsigned long for the
 *   ethtool support mask
 *
 * Parse the EEPROM identification given in @id, and return one of
 * %PORT_TP, %PORT_FIBRE or %PORT_OTHER. If @support is non-%NULL,
 * also set the ethtool %ETHTOOL_LINK_MODE_xxx_BIT corresponding with
 * the connector type.
 *
 * If the port type is not known, returns %PORT_OTHER.
 */
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:
		port = PORT_FIBRE;
		break;

	case SFP_CONNECTOR_RJ45:
		port = PORT_TP;
		break;

	case SFP_CONNECTOR_COPPER_PIGTAIL:
		port = PORT_DA;
		break;

	case SFP_CONNECTOR_UNSPEC:
		if (id->base.e1000_base_t) {
			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_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;
	}

	if (support) {
		switch (port) {
		case PORT_FIBRE:
			phylink_set(support, FIBRE);
			break;

		case PORT_TP:
			phylink_set(support, TP);
			break;
		}
	}

	return port;
}
EXPORT_SYMBOL_GPL(sfp_parse_port);

/**
 * sfp_parse_support() - Parse the eeprom id for supported link modes
 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
 * @id: a pointer to the module's &struct sfp_eeprom_id
 * @support: pointer to an array of unsigned long for the ethtool support mask
 *
 * Parse the EEPROM identification information and derive the supported
 * ethtool link modes for the module.
 */
void sfp_parse_support(struct sfp_bus *bus, const struct sfp_eeprom_id *id,
		       unsigned long *support)
{
	unsigned int br_min, br_nom, br_max;
	__ETHTOOL_DECLARE_LINK_MODE_MASK(modes) = { 0, };

	/* Decode the bitrate information to MBd */
	br_min = br_nom = br_max = 0;
	if (id->base.br_nominal) {
		if (id->base.br_nominal != 255) {
			br_nom = id->base.br_nominal * 100;
			br_min = br_nom - id->base.br_nominal * id->ext.br_min;
			br_max = br_nom + id->base.br_nominal * id->ext.br_max;
		} else if (id->ext.br_max) {
			br_nom = 250 * id->ext.br_max;
			br_max = br_nom + br_nom * id->ext.br_min / 100;
			br_min = br_nom - br_nom * id->ext.br_min / 100;
		}

		/* When using passive cables, in case neither BR,min nor BR,max
		 * are specified, set br_min to 0 as the nominal value is then
		 * used as the maximum.
		 */
		if (br_min == br_max && id->base.sfp_ct_passive)
			br_min = 0;
	}

	/* Set ethtool support from the compliance fields. */
	if (id->base.e10g_base_sr)
		phylink_set(modes, 10000baseSR_Full);
	if (id->base.e10g_base_lr)
		phylink_set(modes, 10000baseLR_Full);
	if (id->base.e10g_base_lrm)
		phylink_set(modes, 10000baseLRM_Full);
	if (id->base.e10g_base_er)
		phylink_set(modes, 10000baseER_Full);
	if (id->base.e1000_base_sx ||
	    id->base.e1000_base_lx ||
	    id->base.e1000_base_cx)
		phylink_set(modes, 1000baseX_Full);
	if (id->base.e1000_base_t) {
		phylink_set(modes, 1000baseT_Half);
		phylink_set(modes, 1000baseT_Full);
	}

	/* 1000Base-PX or 1000Base-BX10 */
	if ((id->base.e_base_px || id->base.e_base_bx10) &&
	    br_min <= 1300 && br_max >= 1200)
		phylink_set(support, 1000baseX_Full);

	/* For active or passive cables, select the link modes
	 * based on the bit rates and the cable compliance bytes.
	 */
	if ((id->base.sfp_ct_passive || id->base.sfp_ct_active) && br_nom) {
		/* This may look odd, but some manufacturers use 12000MBd */
		if (br_min <= 12000 && br_max >= 10300)
			phylink_set(modes, 10000baseCR_Full);
		if (br_min <= 3200 && br_max >= 3100)
			phylink_set(modes, 2500baseX_Full);
		if (br_min <= 1300 && br_max >= 1200)
			phylink_set(modes, 1000baseX_Full);
	}
	if (id->base.sfp_ct_passive) {
		if (id->base.passive.sff8431_app_e)
			phylink_set(modes, 10000baseCR_Full);
	}
	if (id->base.sfp_ct_active) {
		if (id->base.active.sff8431_app_e ||
		    id->base.active.sff8431_lim) {
			phylink_set(modes, 10000baseCR_Full);
		}
	}

	switch (id->base.extended_cc) {
	case 0x00: /* Unspecified */
		break;
	case 0x02: /* 100Gbase-SR4 or 25Gbase-SR */
		phylink_set(modes, 100000baseSR4_Full);
		phylink_set(modes, 25000baseSR_Full);
		break;
	case 0x03: /* 100Gbase-LR4 or 25Gbase-LR */
	case 0x04: /* 100Gbase-ER4 or 25Gbase-ER */
		phylink_set(modes, 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(modes, 100000baseCR4_Full);
		phylink_set(modes, 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(modes, 2500baseX_Full);
		if (id->base.br_nominal >= 12)
			phylink_set(modes, 1000baseX_Full);
	}

	/* If we haven't discovered any modes that this module supports, try
	 * the encoding and bitrate to determine supported modes. Some BiDi
	 * modules (eg, 1310nm/1550nm) are not 1000BASE-BX compliant due to
	 * the differing wavelengths, so do not set any transceiver bits.
	 */
	if (bitmap_empty(modes, __ETHTOOL_LINK_MODE_MASK_NBITS)) {
		/* If the encoding and bit rate allows 1000baseX */
		if (id->base.encoding == SFP_ENCODING_8B10B && br_nom &&
		    br_min <= 1300 && br_max >= 1200)
			phylink_set(modes, 1000baseX_Full);
	}

	bitmap_or(support, support, modes, __ETHTOOL_LINK_MODE_MASK_NBITS);

	phylink_set(support, Autoneg);
	phylink_set(support, Pause);
	phylink_set(support, Asym_Pause);
}
EXPORT_SYMBOL_GPL(sfp_parse_support);

/**
 * sfp_select_interface() - Select appropriate phy_interface_t mode
 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
 * @id: a pointer to the module's &struct sfp_eeprom_id
 * @link_modes: ethtool link modes mask
 *
 * Derive the phy_interface_t mode for the information found in the
 * module's identifying EEPROM and the link modes mask. There is no
 * standard or defined way to derive this information, so we decide
 * based upon the link mode mask.
 */
phy_interface_t sfp_select_interface(struct sfp_bus *bus,
				     const struct sfp_eeprom_id *id,
				     unsigned long *link_modes)
{
	if (phylink_test(link_modes, 10000baseCR_Full) ||
	    phylink_test(link_modes, 10000baseSR_Full) ||
	    phylink_test(link_modes, 10000baseLR_Full) ||
	    phylink_test(link_modes, 10000baseLRM_Full) ||
	    phylink_test(link_modes, 10000baseER_Full))
		return PHY_INTERFACE_MODE_10GKR;

	if (phylink_test(link_modes, 2500baseX_Full))
		return PHY_INTERFACE_MODE_2500BASEX;

	if (id->base.e1000_base_t ||
	    id->base.e100_base_lx ||
	    id->base.e100_base_fx)
		return PHY_INTERFACE_MODE_SGMII;

	if (phylink_test(link_modes, 1000baseX_Full))
		return PHY_INTERFACE_MODE_1000BASEX;

	dev_warn(bus->sfp_dev, "Unable to ascertain link mode\n");

	return PHY_INTERFACE_MODE_NA;
}
EXPORT_SYMBOL_GPL(sfp_select_interface);

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 fwnode_handle *fwnode)
{
	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->fwnode == fwnode) {
			kref_get(&sfp->kref);
			found = sfp;
			break;
		}
	}

	if (!found && new) {
		kref_init(&new->kref);
		new->fwnode = fwnode;
		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)
{
	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;
		}
	}
	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);
		if (bus->phydev && ops && ops->disconnect_phy)
			ops->disconnect_phy(bus->upstream);
	}
	bus->registered = false;
}

/**
 * sfp_get_module_info() - Get the ethtool_modinfo for a SFP module
 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
 * @modinfo: a &struct ethtool_modinfo
 *
 * Fill in the type and eeprom_len parameters in @modinfo for a module on
 * the sfp bus specified by @bus.
 *
 * Returns 0 on success or a negative errno number.
 */
int sfp_get_module_info(struct sfp_bus *bus, struct ethtool_modinfo *modinfo)
{
	return bus->socket_ops->module_info(bus->sfp, modinfo);
}
EXPORT_SYMBOL_GPL(sfp_get_module_info);

/**
 * sfp_get_module_eeprom() - Read the SFP module EEPROM
 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
 * @ee: a &struct ethtool_eeprom
 * @data: buffer to contain the EEPROM data (must be at least @ee->len bytes)
 *
 * Read the EEPROM as specified by the supplied @ee. See the documentation
 * for &struct ethtool_eeprom for the region to be read.
 *
 * Returns 0 on success or a negative errno number.
 */
int sfp_get_module_eeprom(struct sfp_bus *bus, struct ethtool_eeprom *ee,
			  u8 *data)
{
	return bus->socket_ops->module_eeprom(bus->sfp, ee, data);
}
EXPORT_SYMBOL_GPL(sfp_get_module_eeprom);

/**
 * sfp_upstream_start() - Inform the SFP that the network device is up
 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
 *
 * Inform the SFP socket that the network device is now up, so that the
 * module can be enabled by allowing TX_DISABLE to be deasserted. This
 * should be called from the network device driver's &struct net_device_ops
 * ndo_open() method.
 */
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);

/**
 * sfp_upstream_stop() - Inform the SFP that the network device is down
 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
 *
 * Inform the SFP socket that the network device is now up, so that the
 * module can be disabled by asserting TX_DISABLE, disabling the laser
 * in optical modules. This should be called from the network device
 * driver's &struct net_device_ops ndo_stop() method.
 */
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);

static void sfp_upstream_clear(struct sfp_bus *bus)
{
	bus->upstream_ops = NULL;
	bus->upstream = NULL;
	bus->netdev->sfp_bus = NULL;
	bus->netdev = NULL;
}

/**
 * sfp_register_upstream() - Register the neighbouring device
 * @fwnode: firmware node for the SFP bus
 * @ndev: network device associated with the interface
 * @upstream: the upstream private data
 * @ops: the upstream's &struct sfp_upstream_ops
 *
 * Register the upstream device (eg, PHY) with the SFP bus. MAC drivers
 * should use phylink, which will call this function for them. Returns
 * a pointer to the allocated &struct sfp_bus.
 *
 * On error, returns %NULL.
 */
struct sfp_bus *sfp_register_upstream(struct fwnode_handle *fwnode,
				      struct net_device *ndev, void *upstream,
				      const struct sfp_upstream_ops *ops)
{
	struct sfp_bus *bus = sfp_bus_get(fwnode);
	int ret = 0;

	if (bus) {
		rtnl_lock();
		bus->upstream_ops = ops;
		bus->upstream = upstream;
		bus->netdev = ndev;
		ndev->sfp_bus = bus;

		if (bus->sfp) {
			ret = sfp_register_bus(bus);
			if (ret)
				sfp_upstream_clear(bus);
		}
		rtnl_unlock();
	}

	if (ret) {
		sfp_bus_put(bus);
		bus = NULL;
	}

	return bus;
}
EXPORT_SYMBOL_GPL(sfp_register_upstream);

/**
 * sfp_unregister_upstream() - Unregister sfp bus
 * @bus: a pointer to the &struct sfp_bus structure for the sfp module
 *
 * Unregister a previously registered upstream connection for the SFP
 * module. @bus is returned from sfp_register_upstream().
 */
void sfp_unregister_upstream(struct sfp_bus *bus)
{
	rtnl_lock();
	if (bus->sfp)
		sfp_unregister_bus(bus);
	sfp_upstream_clear(bus);
	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);

static void sfp_socket_clear(struct sfp_bus *bus)
{
	bus->sfp_dev = NULL;
	bus->sfp = NULL;
	bus->socket_ops = NULL;
}

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->fwnode);
	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);
			if (ret)
				sfp_socket_clear(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);
	sfp_socket_clear(bus);
	rtnl_unlock();

	sfp_bus_put(bus);
}
EXPORT_SYMBOL_GPL(sfp_unregister_socket);