Merge branch 'Decoupling-PHYLINK-from-struct-net_device'

Ioana Ciornei says:

====================
Decoupling PHYLINK from struct net_device

Following two separate discussion threads in:
  https://www.spinics.net/lists/netdev/msg569087.html
and:
  https://www.spinics.net/lists/netdev/msg570450.html

Previous RFC patch set: https://www.spinics.net/lists/netdev/msg571995.html

PHYLINK was reworked in order to accept multiple operation types,
PHYLINK_NETDEV and PHYLINK_DEV, passed through a phylink_config
structure alongside the corresponding struct device.

One of the main concerns expressed in the RFC was that using notifiers
to signal the corresponding phylink_mac_ops would break PHYLINK's API
unity and that it would become harder to grep for its users.
Using the current approach, we maintain a common API for all users.
Also, printing useful information in PHYLINK, when decoupled from a
net_device, is achieved using dev_err&co on the struct device received
(in DSA's case is the device corresponding to the dsa_switch).

PHYLIB (which PHYLINK uses) was reworked to the extent that it does not
crash when connecting to a PHY and the net_device pointer is NULL.

Lastly, DSA has been reworked in its way that it handles PHYs for ports
that lack a net_device (CPU and DSA ports).  For these, it was
previously using PHYLIB and is now using the PHYLINK_DEV operation type.
Previously, a driver that wanted to support PHY operations on CPU/DSA
ports has to implement .adjust_link(). This patch set not only gives
drivers the options to use PHYLINK uniformly but also urges them to
convert to it. For compatibility, the old code is kept but it will be
removed once all drivers switch over.

The patchset was tested on the NXP LS1021A-TSN board having the
following Ethernet layout:
  https://lkml.org/lkml/2019/5/5/279
The CPU port was moved from the internal RGMII fixed-link (enet2 ->
switch port 4) to an external loopback Cat5 cable between the enet1 port
and the front-facing swp2 SJA1105 port. In this mode, both the master
and the CPU port have an attached PHY which detects link change events:

[   49.105426] fsl-gianfar soc:ethernet@2d50000 eth1: Link is Down
[   50.305486] sja1105 spi0.1: Link is Down
[   53.265596] fsl-gianfar soc:ethernet@2d50000 eth1: Link is Up - 1Gbps/Full - flow control off
[   54.466304] sja1105 spi0.1: Link is Up - 1Gbps/Full - flow control off

Changes in v2:
  - fixed sparse warnings
  - updated 'Documentation/ABI/testing/sysfs-class-net-phydev'
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 179 insertions, 94 deletions

diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index 8f1222324646..418490bda3a4 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -163,6 +163,23 @@ int dsa_port_vid_add(struct dsa_port *dp, u16 vid, u16 flags);
 int dsa_port_vid_del(struct dsa_port *dp, u16 vid);
 int dsa_port_link_register_of(struct dsa_port *dp);
 void dsa_port_link_unregister_of(struct dsa_port *dp);
+void dsa_port_phylink_validate(struct phylink_config *config,
+			       unsigned long *supported,
+			       struct phylink_link_state *state);
+int dsa_port_phylink_mac_link_state(struct phylink_config *config,
+				    struct phylink_link_state *state);
+void dsa_port_phylink_mac_config(struct phylink_config *config,
+				 unsigned int mode,
+				 const struct phylink_link_state *state);
+void dsa_port_phylink_mac_an_restart(struct phylink_config *config);
+void dsa_port_phylink_mac_link_down(struct phylink_config *config,
+				    unsigned int mode,
+				    phy_interface_t interface);
+void dsa_port_phylink_mac_link_up(struct phylink_config *config,
+				  unsigned int mode,
+				  phy_interface_t interface,
+				  struct phy_device *phydev);
+extern const struct phylink_mac_ops dsa_port_phylink_mac_ops;
 
 /* slave.c */
 extern const struct dsa_device_ops notag_netdev_ops;
diff --git a/net/dsa/port.c b/net/dsa/port.c
index ed8ba9daa3ba..d74bc9df1359 100644
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -422,6 +422,108 @@ static struct phy_device *dsa_port_get_phy_device(struct dsa_port *dp)
 	return phydev;
 }
 
+void dsa_port_phylink_validate(struct phylink_config *config,
+			       unsigned long *supported,
+			       struct phylink_link_state *state)
+{
+	struct dsa_port *dp = container_of(config, struct dsa_port, pl_config);
+	struct dsa_switch *ds = dp->ds;
+
+	if (!ds->ops->phylink_validate)
+		return;
+
+	ds->ops->phylink_validate(ds, dp->index, supported, state);
+}
+EXPORT_SYMBOL_GPL(dsa_port_phylink_validate);
+
+int dsa_port_phylink_mac_link_state(struct phylink_config *config,
+				    struct phylink_link_state *state)
+{
+	struct dsa_port *dp = container_of(config, struct dsa_port, pl_config);
+	struct dsa_switch *ds = dp->ds;
+
+	/* Only called for SGMII and 802.3z */
+	if (!ds->ops->phylink_mac_link_state)
+		return -EOPNOTSUPP;
+
+	return ds->ops->phylink_mac_link_state(ds, dp->index, state);
+}
+EXPORT_SYMBOL_GPL(dsa_port_phylink_mac_link_state);
+
+void dsa_port_phylink_mac_config(struct phylink_config *config,
+				 unsigned int mode,
+				 const struct phylink_link_state *state)
+{
+	struct dsa_port *dp = container_of(config, struct dsa_port, pl_config);
+	struct dsa_switch *ds = dp->ds;
+
+	if (!ds->ops->phylink_mac_config)
+		return;
+
+	ds->ops->phylink_mac_config(ds, dp->index, mode, state);
+}
+EXPORT_SYMBOL_GPL(dsa_port_phylink_mac_config);
+
+void dsa_port_phylink_mac_an_restart(struct phylink_config *config)
+{
+	struct dsa_port *dp = container_of(config, struct dsa_port, pl_config);
+	struct dsa_switch *ds = dp->ds;
+
+	if (!ds->ops->phylink_mac_an_restart)
+		return;
+
+	ds->ops->phylink_mac_an_restart(ds, dp->index);
+}
+EXPORT_SYMBOL_GPL(dsa_port_phylink_mac_an_restart);
+
+void dsa_port_phylink_mac_link_down(struct phylink_config *config,
+				    unsigned int mode,
+				    phy_interface_t interface)
+{
+	struct dsa_port *dp = container_of(config, struct dsa_port, pl_config);
+	struct phy_device *phydev = NULL;
+	struct dsa_switch *ds = dp->ds;
+
+	if (dsa_is_user_port(ds, dp->index))
+		phydev = dp->slave->phydev;
+
+	if (!ds->ops->phylink_mac_link_down) {
+		if (ds->ops->adjust_link && phydev)
+			ds->ops->adjust_link(ds, dp->index, phydev);
+		return;
+	}
+
+	ds->ops->phylink_mac_link_down(ds, dp->index, mode, interface);
+}
+EXPORT_SYMBOL_GPL(dsa_port_phylink_mac_link_down);
+
+void dsa_port_phylink_mac_link_up(struct phylink_config *config,
+				  unsigned int mode,
+				  phy_interface_t interface,
+				  struct phy_device *phydev)
+{
+	struct dsa_port *dp = container_of(config, struct dsa_port, pl_config);
+	struct dsa_switch *ds = dp->ds;
+
+	if (!ds->ops->phylink_mac_link_up) {
+		if (ds->ops->adjust_link && phydev)
+			ds->ops->adjust_link(ds, dp->index, phydev);
+		return;
+	}
+
+	ds->ops->phylink_mac_link_up(ds, dp->index, mode, interface, phydev);
+}
+EXPORT_SYMBOL_GPL(dsa_port_phylink_mac_link_up);
+
+const struct phylink_mac_ops dsa_port_phylink_mac_ops = {
+	.validate = dsa_port_phylink_validate,
+	.mac_link_state = dsa_port_phylink_mac_link_state,
+	.mac_config = dsa_port_phylink_mac_config,
+	.mac_an_restart = dsa_port_phylink_mac_an_restart,
+	.mac_link_down = dsa_port_phylink_mac_link_down,
+	.mac_link_up = dsa_port_phylink_mac_link_up,
+};
+
 static int dsa_port_setup_phy_of(struct dsa_port *dp, bool enable)
 {
 	struct dsa_switch *ds = dp->ds;
@@ -499,8 +601,53 @@ static int dsa_port_fixed_link_register_of(struct dsa_port *dp)
 	return 0;
 }
 
+static int dsa_port_phylink_register(struct dsa_port *dp)
+{
+	struct dsa_switch *ds = dp->ds;
+	struct device_node *port_dn = dp->dn;
+	int mode, err;
+
+	mode = of_get_phy_mode(port_dn);
+	if (mode < 0)
+		mode = PHY_INTERFACE_MODE_NA;
+
+	dp->pl_config.dev = ds->dev;
+	dp->pl_config.type = PHYLINK_DEV;
+
+	dp->pl = phylink_create(&dp->pl_config, of_fwnode_handle(port_dn),
+				mode, &dsa_port_phylink_mac_ops);
+	if (IS_ERR(dp->pl)) {
+		pr_err("error creating PHYLINK: %ld\n", PTR_ERR(dp->pl));
+		return PTR_ERR(dp->pl);
+	}
+
+	err = phylink_of_phy_connect(dp->pl, port_dn, 0);
+	if (err) {
+		pr_err("could not attach to PHY: %d\n", err);
+		goto err_phy_connect;
+	}
+
+	rtnl_lock();
+	phylink_start(dp->pl);
+	rtnl_unlock();
+
+	return 0;
+
+err_phy_connect:
+	phylink_destroy(dp->pl);
+	return err;
+}
+
 int dsa_port_link_register_of(struct dsa_port *dp)
 {
+	struct dsa_switch *ds = dp->ds;
+
+	if (!ds->ops->adjust_link)
+		return dsa_port_phylink_register(dp);
+
+	dev_warn(ds->dev,
+		 "Using legacy PHYLIB callbacks. Please migrate to PHYLINK!\n");
+
 	if (of_phy_is_fixed_link(dp->dn))
 		return dsa_port_fixed_link_register_of(dp);
 	else
@@ -509,6 +656,16 @@ int dsa_port_link_register_of(struct dsa_port *dp)
 
 void dsa_port_link_unregister_of(struct dsa_port *dp)
 {
+	struct dsa_switch *ds = dp->ds;
+
+	if (!ds->ops->adjust_link) {
+		rtnl_lock();
+		phylink_disconnect_phy(dp->pl);
+		rtnl_unlock();
+		phylink_destroy(dp->pl);
+		return;
+	}
+
 	if (of_phy_is_fixed_link(dp->dn))
 		of_phy_deregister_fixed_link(dp->dn);
 	else
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 9892ca1f6859..1e2ae9d59b88 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -1164,98 +1164,6 @@ static struct device_type dsa_type = {
 	.name	= "dsa",
 };
 
-static void dsa_slave_phylink_validate(struct net_device *dev,
-				       unsigned long *supported,
-				       struct phylink_link_state *state)
-{
-	struct dsa_port *dp = dsa_slave_to_port(dev);
-	struct dsa_switch *ds = dp->ds;
-
-	if (!ds->ops->phylink_validate)
-		return;
-
-	ds->ops->phylink_validate(ds, dp->index, supported, state);
-}
-
-static int dsa_slave_phylink_mac_link_state(struct net_device *dev,
-					    struct phylink_link_state *state)
-{
-	struct dsa_port *dp = dsa_slave_to_port(dev);
-	struct dsa_switch *ds = dp->ds;
-
-	/* Only called for SGMII and 802.3z */
-	if (!ds->ops->phylink_mac_link_state)
-		return -EOPNOTSUPP;
-
-	return ds->ops->phylink_mac_link_state(ds, dp->index, state);
-}
-
-static void dsa_slave_phylink_mac_config(struct net_device *dev,
-					 unsigned int mode,
-					 const struct phylink_link_state *state)
-{
-	struct dsa_port *dp = dsa_slave_to_port(dev);
-	struct dsa_switch *ds = dp->ds;
-
-	if (!ds->ops->phylink_mac_config)
-		return;
-
-	ds->ops->phylink_mac_config(ds, dp->index, mode, state);
-}
-
-static void dsa_slave_phylink_mac_an_restart(struct net_device *dev)
-{
-	struct dsa_port *dp = dsa_slave_to_port(dev);
-	struct dsa_switch *ds = dp->ds;
-
-	if (!ds->ops->phylink_mac_an_restart)
-		return;
-
-	ds->ops->phylink_mac_an_restart(ds, dp->index);
-}
-
-static void dsa_slave_phylink_mac_link_down(struct net_device *dev,
-					    unsigned int mode,
-					    phy_interface_t interface)
-{
-	struct dsa_port *dp = dsa_slave_to_port(dev);
-	struct dsa_switch *ds = dp->ds;
-
-	if (!ds->ops->phylink_mac_link_down) {
-		if (ds->ops->adjust_link && dev->phydev)
-			ds->ops->adjust_link(ds, dp->index, dev->phydev);
-		return;
-	}
-
-	ds->ops->phylink_mac_link_down(ds, dp->index, mode, interface);
-}
-
-static void dsa_slave_phylink_mac_link_up(struct net_device *dev,
-					  unsigned int mode,
-					  phy_interface_t interface,
-					  struct phy_device *phydev)
-{
-	struct dsa_port *dp = dsa_slave_to_port(dev);
-	struct dsa_switch *ds = dp->ds;
-
-	if (!ds->ops->phylink_mac_link_up) {
-		if (ds->ops->adjust_link && dev->phydev)
-			ds->ops->adjust_link(ds, dp->index, dev->phydev);
-		return;
-	}
-
-	ds->ops->phylink_mac_link_up(ds, dp->index, mode, interface, phydev);
-}
-
-static const struct phylink_mac_ops dsa_slave_phylink_mac_ops = {
-	.validate = dsa_slave_phylink_validate,
-	.mac_link_state = dsa_slave_phylink_mac_link_state,
-	.mac_config = dsa_slave_phylink_mac_config,
-	.mac_an_restart = dsa_slave_phylink_mac_an_restart,
-	.mac_link_down = dsa_slave_phylink_mac_link_down,
-	.mac_link_up = dsa_slave_phylink_mac_link_up,
-};
-
 void dsa_port_phylink_mac_change(struct dsa_switch *ds, int port, bool up)
 {
 	const struct dsa_port *dp = dsa_to_port(ds, port);
@@ -1303,8 +1211,11 @@ static int dsa_slave_phy_setup(struct net_device *slave_dev)
 	if (mode < 0)
 		mode = PHY_INTERFACE_MODE_NA;
 
-	dp->pl = phylink_create(slave_dev, of_fwnode_handle(port_dn), mode,
-				&dsa_slave_phylink_mac_ops);
+	dp->pl_config.dev = &slave_dev->dev;
+	dp->pl_config.type = PHYLINK_NETDEV;
+
+	dp->pl = phylink_create(&dp->pl_config, of_fwnode_handle(port_dn), mode,
+				&dsa_port_phylink_mac_ops);
 	if (IS_ERR(dp->pl)) {
 		netdev_err(slave_dev,
 			   "error creating PHYLINK: %ld\n", PTR_ERR(dp->pl));