[PATCH net-next 1/2] net: phy: add core phylib sfp support

[Russell King <rmk+kernel@armlinux.org.uk>]

Add core phylib help for supporting SFP sockets on PHYs.  This provides
a mechanism to inform the SFP layer about PHY up/down events, and also
unregister the SFP bus when the PHY is going away.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
 drivers/net/phy/phy.c        |  7 ++++
 drivers/net/phy/phy_device.c | 66 ++++++++++++++++++++++++++++++++++++
 include/linux/phy.h          | 11 ++++++
 3 files changed, 84 insertions(+)

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 0a314cf45408..cb9ab24ee898 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -23,6 +23,7 @@
 #include <linux/ethtool.h>
 #include <linux/phy.h>
 #include <linux/phy_led_triggers.h>
+#include <linux/sfp.h>
 #include <linux/workqueue.h>
 #include <linux/mdio.h>
 #include <linux/io.h>
@@ -866,6 +867,9 @@ void phy_stop(struct phy_device *phydev)
 
 	mutex_lock(&phydev->lock);
 
+	if (phydev->sfp_bus)
+		sfp_upstream_stop(phydev->sfp_bus);
+
 	phydev->state = PHY_HALTED;
 
 	mutex_unlock(&phydev->lock);
@@ -900,6 +904,9 @@ void phy_start(struct phy_device *phydev)
 		goto out;
 	}
 
+	if (phydev->sfp_bus)
+		sfp_upstream_start(phydev->sfp_bus);
+
 	/* if phy was suspended, bring the physical link up again */
 	__phy_resume(phydev);
 
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 9ddfb8b0ce04..ff47ec245100 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -27,6 +27,7 @@
 #include <linux/bitmap.h>
 #include <linux/phy.h>
 #include <linux/phy_led_triggers.h>
+#include <linux/sfp.h>
 #include <linux/mdio.h>
 #include <linux/io.h>
 #include <linux/uaccess.h>
@@ -1174,6 +1175,65 @@ phy_standalone_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(phy_standalone);
 
+/**
+ * phy_sfp_attach - attach the SFP bus to the PHY upstream network device
+ * @upstream: pointer to the phy device
+ * @bus: sfp bus representing cage being attached
+ *
+ * This is used to fill in the sfp_upstream_ops .attach member.
+ */
+void phy_sfp_attach(void *upstream, struct sfp_bus *bus)
+{
+	struct phy_device *phydev = upstream;
+
+	if (phydev->attached_dev)
+		phydev->attached_dev->sfp_bus = bus;
+	phydev->sfp_bus_attached = true;
+}
+EXPORT_SYMBOL(phy_sfp_attach);
+
+/**
+ * phy_sfp_detach - detach the SFP bus from the PHY upstream network device
+ * @upstream: pointer to the phy device
+ * @bus: sfp bus representing cage being attached
+ *
+ * This is used to fill in the sfp_upstream_ops .detach member.
+ */
+void phy_sfp_detach(void *upstream, struct sfp_bus *bus)
+{
+	struct phy_device *phydev = upstream;
+
+	if (phydev->attached_dev)
+		phydev->attached_dev->sfp_bus = NULL;
+	phydev->sfp_bus_attached = false;
+}
+EXPORT_SYMBOL(phy_sfp_detach);
+
+/**
+ * phy_sfp_probe - probe for a SFP cage attached to this PHY device
+ * @phydev: Pointer to phy_device
+ * @ops: SFP's upstream operations
+ */
+int phy_sfp_probe(struct phy_device *phydev,
+		  const struct sfp_upstream_ops *ops)
+{
+	struct sfp_bus *bus;
+	int ret;
+
+	if (phydev->mdio.dev.fwnode) {
+		bus = sfp_bus_find_fwnode(phydev->mdio.dev.fwnode);
+		if (IS_ERR(bus))
+			return PTR_ERR(bus);
+
+		phydev->sfp_bus = bus;
+
+		ret = sfp_bus_add_upstream(bus, phydev, ops);
+		sfp_bus_put(bus);
+	}
+	return 0;
+}
+EXPORT_SYMBOL(phy_sfp_probe);
+
 /**
  * phy_attach_direct - attach a network device to a given PHY device pointer
  * @dev: network device to attach
@@ -1249,6 +1309,9 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
 	if (dev) {
 		phydev->attached_dev = dev;
 		dev->phydev = phydev;
+
+		if (phydev->sfp_bus_attached)
+			dev->sfp_bus = phydev->sfp_bus;
 	}
 
 	/* Some Ethernet drivers try to connect to a PHY device before
@@ -2333,6 +2396,9 @@ static int phy_remove(struct device *dev)
 	phydev->state = PHY_DOWN;
 	mutex_unlock(&phydev->lock);
 
+	sfp_bus_del_upstream(phydev->sfp_bus);
+	phydev->sfp_bus = NULL;
+
 	if (phydev->drv && phydev->drv->remove) {
 		phydev->drv->remove(phydev);
 
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 1f9a141ccfb4..9753d9f28d73 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -203,6 +203,8 @@ static inline const char *phy_modes(phy_interface_t interface)
 
 struct device;
 struct phylink;
+struct sfp_bus;
+struct sfp_upstream_ops;
 struct sk_buff;
 
 /*
@@ -342,6 +344,8 @@ struct phy_c45_device_ids {
  * dev_flags: Device-specific flags used by the PHY driver.
  * irq: IRQ number of the PHY's interrupt (-1 if none)
  * phy_timer: The timer for handling the state machine
+ * sfp_bus_attached: flag indicating whether the SFP bus has been attached
+ * sfp_bus: SFP bus attached to this PHY's fiber port
  * attached_dev: The attached enet driver's device instance ptr
  * adjust_link: Callback for the enet controller to respond to
  * changes in the link state.
@@ -430,6 +434,9 @@ struct phy_device {
 
 	struct mutex lock;
 
+	/* This may be modified under the rtnl lock */
+	bool sfp_bus_attached;
+	struct sfp_bus *sfp_bus;
 	struct phylink *phylink;
 	struct net_device *attached_dev;
 
@@ -1015,6 +1022,10 @@ int phy_suspend(struct phy_device *phydev);
 int phy_resume(struct phy_device *phydev);
 int __phy_resume(struct phy_device *phydev);
 int phy_loopback(struct phy_device *phydev, bool enable);
+void phy_sfp_attach(void *upstream, struct sfp_bus *bus);
+void phy_sfp_detach(void *upstream, struct sfp_bus *bus);
+int phy_sfp_probe(struct phy_device *phydev,
+	          const struct sfp_upstream_ops *ops);
 struct phy_device *phy_attach(struct net_device *dev, const char *bus_id,
 			      phy_interface_t interface);
 struct phy_device *phy_find_first(struct mii_bus *bus);
-- 
2.20.1