Adding upstream version 5.10.209.upstream/5.10.209

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 839 insertions, 0 deletions

diff --git a/drivers/net/phy/sfp-bus.c b/drivers/net/phy/sfp-bus.c
new file mode 100644
index 000000000..850915a37
--- /dev/null
+++ b/drivers/net/phy/sfp-bus.c
@@ -0,0 +1,839 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/export.h>
+#include <linux/kref.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/phylink.h>
+#include <linux/property.h>
+#include <linux/rtnetlink.h>
+#include <linux/slab.h>
+
+#include "sfp.h"
+
+struct sfp_quirk {
+	const char *vendor;
+	const char *part;
+	void (*modes)(const struct sfp_eeprom_id *id, unsigned long *modes);
+};
+
+/**
+ * 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_quirk *sfp_quirk;
+
+	const struct sfp_upstream_ops *upstream_ops;
+	void *upstream;
+	struct phy_device *phydev;
+
+	bool registered;
+	bool started;
+};
+
+static void sfp_quirk_2500basex(const struct sfp_eeprom_id *id,
+				unsigned long *modes)
+{
+	phylink_set(modes, 2500baseX_Full);
+}
+
+static void sfp_quirk_ubnt_uf_instant(const struct sfp_eeprom_id *id,
+				      unsigned long *modes)
+{
+	/* Ubiquiti U-Fiber Instant module claims that support all transceiver
+	 * types including 10G Ethernet which is not truth. So clear all claimed
+	 * modes and set only one mode which module supports: 1000baseX_Full.
+	 */
+	phylink_zero(modes);
+	phylink_set(modes, 1000baseX_Full);
+}
+
+static const struct sfp_quirk sfp_quirks[] = {
+	{
+		// Alcatel Lucent G-010S-P can operate at 2500base-X, but
+		// incorrectly report 2500MBd NRZ in their EEPROM
+		.vendor = "ALCATELLUCENT",
+		.part = "G010SP",
+		.modes = sfp_quirk_2500basex,
+	}, {
+		// Alcatel Lucent G-010S-A can operate at 2500base-X, but
+		// report 3.2GBd NRZ in their EEPROM
+		.vendor = "ALCATELLUCENT",
+		.part = "3FE46541AA",
+		.modes = sfp_quirk_2500basex,
+	}, {
+		// Huawei MA5671A can operate at 2500base-X, but report 1.2GBd
+		// NRZ in their EEPROM
+		.vendor = "HUAWEI",
+		.part = "MA5671A",
+		.modes = sfp_quirk_2500basex,
+	}, {
+		// Lantech 8330-262D-E can operate at 2500base-X, but
+		// incorrectly report 2500MBd NRZ in their EEPROM
+		.vendor = "Lantech",
+		.part = "8330-262D-E",
+		.modes = sfp_quirk_2500basex,
+	}, {
+		.vendor = "UBNT",
+		.part = "UF-INSTANT",
+		.modes = sfp_quirk_ubnt_uf_instant,
+	},
+};
+
+static size_t sfp_strlen(const char *str, size_t maxlen)
+{
+	size_t size, i;
+
+	/* Trailing characters should be filled with space chars */
+	for (i = 0, size = 0; i < maxlen; i++)
+		if (str[i] != ' ')
+			size = i + 1;
+
+	return size;
+}
+
+static bool sfp_match(const char *qs, const char *str, size_t len)
+{
+	if (!qs)
+		return true;
+	if (strlen(qs) != len)
+		return false;
+	return !strncmp(qs, str, len);
+}
+
+static const struct sfp_quirk *sfp_lookup_quirk(const struct sfp_eeprom_id *id)
+{
+	const struct sfp_quirk *q;
+	unsigned int i;
+	size_t vs, ps;
+
+	vs = sfp_strlen(id->base.vendor_name, ARRAY_SIZE(id->base.vendor_name));
+	ps = sfp_strlen(id->base.vendor_pn, ARRAY_SIZE(id->base.vendor_pn));
+
+	for (i = 0, q = sfp_quirks; i < ARRAY_SIZE(sfp_quirks); i++, q++)
+		if (sfp_match(q->vendor, id->base.vendor_name, vs) &&
+		    sfp_match(q->part, id->base.vendor_pn, ps))
+			return q;
+
+	return NULL;
+}
+
+/**
+ * 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 SFF8024_CONNECTOR_SC:
+	case SFF8024_CONNECTOR_FIBERJACK:
+	case SFF8024_CONNECTOR_LC:
+	case SFF8024_CONNECTOR_MT_RJ:
+	case SFF8024_CONNECTOR_MU:
+	case SFF8024_CONNECTOR_OPTICAL_PIGTAIL:
+	case SFF8024_CONNECTOR_MPO_1X12:
+	case SFF8024_CONNECTOR_MPO_2X16:
+		port = PORT_FIBRE;
+		break;
+
+	case SFF8024_CONNECTOR_RJ45:
+		port = PORT_TP;
+		break;
+
+	case SFF8024_CONNECTOR_COPPER_PIGTAIL:
+		port = PORT_DA;
+		break;
+
+	case SFF8024_CONNECTOR_UNSPEC:
+		if (id->base.e1000_base_t) {
+			port = PORT_TP;
+			break;
+		}
+		fallthrough;
+	case SFF8024_CONNECTOR_SG: /* guess */
+	case SFF8024_CONNECTOR_HSSDC_II:
+	case SFF8024_CONNECTOR_NOSEPARATE:
+	case SFF8024_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_may_have_phy() - indicate whether the module may have a PHY
+ * @bus: a pointer to the &struct sfp_bus structure for the sfp module
+ * @id: a pointer to the module's &struct sfp_eeprom_id
+ *
+ * Parse the EEPROM identification given in @id, and return whether
+ * this module may have a PHY.
+ */
+bool sfp_may_have_phy(struct sfp_bus *bus, const struct sfp_eeprom_id *id)
+{
+	if (id->base.e1000_base_t)
+		return true;
+
+	if (id->base.phys_id != SFF8024_ID_DWDM_SFP) {
+		switch (id->base.extended_cc) {
+		case SFF8024_ECC_10GBASE_T_SFI:
+		case SFF8024_ECC_10GBASE_T_SR:
+		case SFF8024_ECC_5GBASE_T:
+		case SFF8024_ECC_2_5GBASE_T:
+			return true;
+		}
+	}
+
+	return false;
+}
+EXPORT_SYMBOL_GPL(sfp_may_have_phy);
+
+/**
+ * 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(modes, 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 SFF8024_ECC_UNSPEC:
+		break;
+	case SFF8024_ECC_100GBASE_SR4_25GBASE_SR:
+		phylink_set(modes, 100000baseSR4_Full);
+		phylink_set(modes, 25000baseSR_Full);
+		break;
+	case SFF8024_ECC_100GBASE_LR4_25GBASE_LR:
+	case SFF8024_ECC_100GBASE_ER4_25GBASE_ER:
+		phylink_set(modes, 100000baseLR4_ER4_Full);
+		break;
+	case SFF8024_ECC_100GBASE_CR4:
+		phylink_set(modes, 100000baseCR4_Full);
+		fallthrough;
+	case SFF8024_ECC_25GBASE_CR_S:
+	case SFF8024_ECC_25GBASE_CR_N:
+		phylink_set(modes, 25000baseCR_Full);
+		break;
+	case SFF8024_ECC_10GBASE_T_SFI:
+	case SFF8024_ECC_10GBASE_T_SR:
+		phylink_set(modes, 10000baseT_Full);
+		break;
+	case SFF8024_ECC_5GBASE_T:
+		phylink_set(modes, 5000baseT_Full);
+		break;
+	case SFF8024_ECC_2_5GBASE_T:
+		phylink_set(modes, 2500baseT_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 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 bit rate allows 1000baseX */
+		if (br_nom && br_min <= 1300 && br_max >= 1200)
+			phylink_set(modes, 1000baseX_Full);
+	}
+
+	if (bus->sfp_quirk)
+		bus->sfp_quirk->modes(id, modes);
+
+	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
+ * @link_modes: ethtool link modes mask
+ *
+ * Derive the phy_interface_t mode for the SFP module from the link
+ * modes mask.
+ */
+phy_interface_t sfp_select_interface(struct sfp_bus *bus,
+				     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) ||
+	    phylink_test(link_modes, 10000baseT_Full))
+		return PHY_INTERFACE_MODE_10GBASER;
+
+	if (phylink_test(link_modes, 2500baseX_Full))
+		return PHY_INTERFACE_MODE_2500BASEX;
+
+	if (phylink_test(link_modes, 1000baseT_Half) ||
+	    phylink_test(link_modes, 1000baseT_Full))
+		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);
+}
+
+/**
+ * sfp_bus_put() - put a reference on the &struct sfp_bus
+ * @bus: the &struct sfp_bus found via sfp_bus_find_fwnode()
+ *
+ * Put a reference on the &struct sfp_bus and free the underlying structure
+ * if this was the last reference.
+ */
+void sfp_bus_put(struct sfp_bus *bus)
+{
+	if (bus)
+		kref_put_mutex(&bus->kref, sfp_bus_release, &sfp_mutex);
+}
+EXPORT_SYMBOL_GPL(sfp_bus_put);
+
+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->registered = true;
+	bus->socket_ops->attach(bus->sfp);
+	if (bus->started)
+		bus->socket_ops->start(bus->sfp);
+	bus->upstream_ops->attach(bus->upstream, bus);
+	return 0;
+}
+
+static void sfp_unregister_bus(struct sfp_bus *bus)
+{
+	const struct sfp_upstream_ops *ops = bus->upstream_ops;
+
+	if (bus->registered) {
+		bus->upstream_ops->detach(bus->upstream, bus);
+		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;
+}
+
+/**
+ * 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;
+}
+
+/**
+ * sfp_bus_find_fwnode() - parse and locate the SFP bus from fwnode
+ * @fwnode: firmware node for the parent device (MAC or PHY)
+ *
+ * Parse the parent device's firmware node for a SFP bus, and locate
+ * the sfp_bus structure, incrementing its reference count.  This must
+ * be put via sfp_bus_put() when done.
+ *
+ * Returns:
+ * 	    - on success, a pointer to the sfp_bus structure,
+ *	    - %NULL if no SFP is specified,
+ * 	    - on failure, an error pointer value:
+ *
+ * 	      - corresponding to the errors detailed for
+ * 	        fwnode_property_get_reference_args().
+ * 	      - %-ENOMEM if we failed to allocate the bus.
+ *	      - an error from the upstream's connect_phy() method.
+ */
+struct sfp_bus *sfp_bus_find_fwnode(struct fwnode_handle *fwnode)
+{
+	struct fwnode_reference_args ref;
+	struct sfp_bus *bus;
+	int ret;
+
+	ret = fwnode_property_get_reference_args(fwnode, "sfp", NULL,
+						 0, 0, &ref);
+	if (ret == -ENOENT)
+		return NULL;
+	else if (ret < 0)
+		return ERR_PTR(ret);
+
+	if (!fwnode_device_is_available(ref.fwnode)) {
+		fwnode_handle_put(ref.fwnode);
+		return NULL;
+	}
+
+	bus = sfp_bus_get(ref.fwnode);
+	fwnode_handle_put(ref.fwnode);
+	if (!bus)
+		return ERR_PTR(-ENOMEM);
+
+	return bus;
+}
+EXPORT_SYMBOL_GPL(sfp_bus_find_fwnode);
+
+/**
+ * sfp_bus_add_upstream() - parse and register the neighbouring device
+ * @bus: the &struct sfp_bus found via sfp_bus_find_fwnode()
+ * @upstream: the upstream private data
+ * @ops: the upstream's &struct sfp_upstream_ops
+ *
+ * Add upstream driver for the SFP bus, and if the bus is complete, register
+ * the SFP bus using sfp_register_upstream().  This takes a reference on the
+ * bus, so it is safe to put the bus after this call.
+ *
+ * Returns:
+ * 	    - on success, a pointer to the sfp_bus structure,
+ *	    - %NULL if no SFP is specified,
+ * 	    - on failure, an error pointer value:
+ *
+ * 	      - corresponding to the errors detailed for
+ * 	        fwnode_property_get_reference_args().
+ * 	      - %-ENOMEM if we failed to allocate the bus.
+ *	      - an error from the upstream's connect_phy() method.
+ */
+int sfp_bus_add_upstream(struct sfp_bus *bus, void *upstream,
+			 const struct sfp_upstream_ops *ops)
+{
+	int ret;
+
+	/* If no bus, return success */
+	if (!bus)
+		return 0;
+
+	rtnl_lock();
+	kref_get(&bus->kref);
+	bus->upstream_ops = ops;
+	bus->upstream = upstream;
+
+	if (bus->sfp) {
+		ret = sfp_register_bus(bus);
+		if (ret)
+			sfp_upstream_clear(bus);
+	} else {
+		ret = 0;
+	}
+	rtnl_unlock();
+
+	if (ret)
+		sfp_bus_put(bus);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(sfp_bus_add_upstream);
+
+/**
+ * sfp_bus_del_upstream() - Delete a sfp bus
+ * @bus: a pointer to the &struct sfp_bus structure for the sfp module
+ *
+ * Delete a previously registered upstream connection for the SFP
+ * module. @bus should have been added by sfp_bus_add_upstream().
+ */
+void sfp_bus_del_upstream(struct sfp_bus *bus)
+{
+	if (bus) {
+		rtnl_lock();
+		if (bus->sfp)
+			sfp_unregister_bus(bus);
+		sfp_upstream_clear(bus);
+		rtnl_unlock();
+
+		sfp_bus_put(bus);
+	}
+}
+EXPORT_SYMBOL_GPL(sfp_bus_del_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;
+
+	bus->sfp_quirk = sfp_lookup_quirk(id);
+
+	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);
+
+	bus->sfp_quirk = NULL;
+}
+EXPORT_SYMBOL_GPL(sfp_module_remove);
+
+int sfp_module_start(struct sfp_bus *bus)
+{
+	const struct sfp_upstream_ops *ops = sfp_get_upstream_ops(bus);
+	int ret = 0;
+
+	if (ops && ops->module_start)
+		ret = ops->module_start(bus->upstream);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(sfp_module_start);
+
+void sfp_module_stop(struct sfp_bus *bus)
+{
+	const struct sfp_upstream_ops *ops = sfp_get_upstream_ops(bus);
+
+	if (ops && ops->module_stop)
+		ops->module_stop(bus->upstream);
+}
+EXPORT_SYMBOL_GPL(sfp_module_stop);
+
+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->upstream_ops) {
+			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->upstream_ops)
+		sfp_unregister_bus(bus);
+	sfp_socket_clear(bus);
+	rtnl_unlock();
+
+	sfp_bus_put(bus);
+}
+EXPORT_SYMBOL_GPL(sfp_unregister_socket);