Merge branch 'sja1105-phylink-updates'

Russell King says:

====================
net: dsa: sja1105: phylink updates

This series updates the phylink implementation in sja1105 to use the
supported_interfaces bitmap, convert to the mac_select_pcs() interface,
mark as non-legacy, and get rid of the validation method.

As a final step, enable switching between SGMII and 2500BASE-X as it
is a feature that Vladimir desires.

Specifically, the patches in this series:

1. Populates the supported_interfaces bitmap.
2. As a result of the supported_interfaces bitmap being populated,
   sja1105 no longer needs to check the interface mode as phylink
   will do this.
3. Switch away from using phylink_set_pcs(), using the mac_select_pcs()
   method instead.
4. Mark the driver as not-legacy
5. Fill in mac_capabilities using _exactly_ the same conditions as is
   currently used to decide which link modes to support, and convert
   to use phylink_generic_validate()
6. Add brand new support to permit switching between SGMII and
   2500BASE-X modes of operation as per Vladimir's single patch that
   performs steps 1, 2, 5 and 6 in one go.

There are some additional changes in Vladimir's single patch that I
have not included:

* validation of priv->phy_mode[] in sja1105_phylink_get_caps(). The
  driver has already validated the phy_mode for each port in
  sja1105_init_mii_settings(), and a failure here will prevent the
  driver reaching sja1105_phylink_get_caps().

* Changing the decisions on which mac_capabilities to set. Vladimir's
  patch always sets MAC_10FD | MAC_100FD | MAC_1000FD despite the
  current code clearly making the 1G speed conditional on the
  xmii_mode for the port. The change in decision making may be
  visible when in PHY_INTERFACE_MODE_INTERNAL mode, for which
  the phylink_generic_validate() will pass through all the MAC
  capabilities as ethtool link modes.

  Hence, if we have PHY_INTERFACE_MODE_INTERNAL but supports_rgmii[]
  or supports_sgmii[] is non-zero, currently we do not get 1G speeds.
  With Vladimir's additional change, we will get 1G speeds.

  While it is not clear whether that can happen, I feel changing the
  decision making should be a separate patch.

* The decision for MAC_2500FD is made differently -
  sja1105_init_mii_settings() allows PHY_INTERFACE_MODE_2500BASEX
  when supports_2500basex[] is non-zero, and is not based on any other
  condition such as supports_sgmii[] or supports_rgmii[]. Vladimir's
  patch makes it additionally conditional on those supports_.gmii[]
  settings, which is a functional change that should be made in a
  separate patch - and if desired, then sja1105_init_mii_settings()
  should also be updated at the same time.

Consequently, I believe that my previous objections to Vladimir's
single patch approach are well founded and justified, even through
Vladimir is the maintainer of this driver. I have no objection to
the additional changes, I just don't think they should all be wrapped
up into a single patch that converts the way validation is done _and_
also makes a bunch of other functional changes.

RFC->non-RFC: added Vladimir's Reviewed-by's, fixed the typo in the
commit message of patch 6, and removed the phrase at the end of a
comment as requested.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/sja1105/sja1105_main.c

@@ -1358,37 +1358,16 @@ static int sja1105_adjust_port_config(struct sja1105_private *priv, int port,
 	return sja1105_clocking_setup_port(priv, port);
 }
 
-/* The SJA1105 MAC programming model is through the static config (the xMII
- * Mode table cannot be dynamically reconfigured), and we have to program
- * that early (earlier than PHYLINK calls us, anyway).
- * So just error out in case the connected PHY attempts to change the initial
- * system interface MII protocol from what is defined in the DT, at least for
- * now.
- */
-static bool sja1105_phy_mode_mismatch(struct sja1105_private *priv, int port,
-				      phy_interface_t interface)
-{
-	return priv->phy_mode[port] != interface;
-}
-
-static void sja1105_mac_config(struct dsa_switch *ds, int port,
-			       unsigned int mode,
-			       const struct phylink_link_state *state)
+static struct phylink_pcs *
+sja1105_mac_select_pcs(struct dsa_switch *ds, int port, phy_interface_t iface)
 {
-	struct dsa_port *dp = dsa_to_port(ds, port);
 	struct sja1105_private *priv = ds->priv;
-	struct dw_xpcs *xpcs;
-
-	if (sja1105_phy_mode_mismatch(priv, port, state->interface)) {
-		dev_err(ds->dev, "Changing PHY mode to %s not supported!\n",
-			phy_modes(state->interface));
-		return;
-	}
-
-	xpcs = priv->xpcs[port];
+	struct dw_xpcs *xpcs = priv->xpcs[port];
 
 	if (xpcs)
-		phylink_set_pcs(dp->pl, &xpcs->pcs);
+		return &xpcs->pcs;
+
+	return NULL;
 }
 
 static void sja1105_mac_link_down(struct dsa_switch *ds, int port,
@@ -1412,48 +1391,53 @@ static void sja1105_mac_link_up(struct dsa_switch *ds, int port,
 	sja1105_inhibit_tx(priv, BIT(port), false);
 }
 
-static void sja1105_phylink_validate(struct dsa_switch *ds, int port,
-				     unsigned long *supported,
-				     struct phylink_link_state *state)
+static void sja1105_phylink_get_caps(struct dsa_switch *ds, int port,
+				     struct phylink_config *config)
 {
-	/* Construct a new mask which exhaustively contains all link features
-	 * supported by the MAC, and then apply that (logical AND) to what will
-	 * be sent to the PHY for "marketing".
-	 */
-	__ETHTOOL_DECLARE_LINK_MODE_MASK(mask) = { 0, };
 	struct sja1105_private *priv = ds->priv;
 	struct sja1105_xmii_params_entry *mii;
+	phy_interface_t phy_mode;
 
-	mii = priv->static_config.tables[BLK_IDX_XMII_PARAMS].entries;
+	/* This driver does not make use of the speed, duplex, pause or the
+	 * advertisement in its mac_config, so it is safe to mark this driver
+	 * as non-legacy.
+	 */
+	config->legacy_pre_march2020 = false;
 
-	/* include/linux/phylink.h says:
-	 *     When @state->interface is %PHY_INTERFACE_MODE_NA, phylink
-	 *     expects the MAC driver to return all supported link modes.
+	phy_mode = priv->phy_mode[port];
+	if (phy_mode == PHY_INTERFACE_MODE_SGMII ||
+	    phy_mode == PHY_INTERFACE_MODE_2500BASEX) {
+		/* Changing the PHY mode on SERDES ports is possible and makes
+		 * sense, because that is done through the XPCS. We allow
+		 * changes between SGMII and 2500base-X.
 		 */
-	if (state->interface != PHY_INTERFACE_MODE_NA &&
-	    sja1105_phy_mode_mismatch(priv, port, state->interface)) {
-		linkmode_zero(supported);
-		return;
+		if (priv->info->supports_sgmii[port])
+			__set_bit(PHY_INTERFACE_MODE_SGMII,
+				  config->supported_interfaces);
+
+		if (priv->info->supports_2500basex[port])
+			__set_bit(PHY_INTERFACE_MODE_2500BASEX,
+				  config->supported_interfaces);
+	} else {
+		/* The SJA1105 MAC programming model is through the static
+		 * config (the xMII Mode table cannot be dynamically
+		 * reconfigured), and we have to program that early.
+		 */
+		__set_bit(phy_mode, config->supported_interfaces);
 	}
 
 	/* The MAC does not support pause frames, and also doesn't
 	 * support half-duplex traffic modes.
 	 */
-	phylink_set(mask, Autoneg);
-	phylink_set(mask, MII);
-	phylink_set(mask, 10baseT_Full);
-	phylink_set(mask, 100baseT_Full);
-	phylink_set(mask, 100baseT1_Full);
+	config->mac_capabilities = MAC_10FD | MAC_100FD;
+
+	mii = priv->static_config.tables[BLK_IDX_XMII_PARAMS].entries;
 	if (mii->xmii_mode[port] == XMII_MODE_RGMII ||
 	    mii->xmii_mode[port] == XMII_MODE_SGMII)
-		phylink_set(mask, 1000baseT_Full);
-	if (priv->info->supports_2500basex[port]) {
-		phylink_set(mask, 2500baseT_Full);
-		phylink_set(mask, 2500baseX_Full);
-	}
+		config->mac_capabilities |= MAC_1000FD;
 
-	linkmode_and(supported, supported, mask);
-	linkmode_and(state->advertising, state->advertising, mask);
+	if (priv->info->supports_2500basex[port])
+		config->mac_capabilities |= MAC_2500FD;
 }
 
 static int
@@ -3152,8 +3136,8 @@ static const struct dsa_switch_ops sja1105_switch_ops = {
 	.set_ageing_time	= sja1105_set_ageing_time,
 	.port_change_mtu	= sja1105_change_mtu,
 	.port_max_mtu		= sja1105_get_max_mtu,
-	.phylink_validate	= sja1105_phylink_validate,
-	.phylink_mac_config	= sja1105_mac_config,
+	.phylink_get_caps	= sja1105_phylink_get_caps,
+	.phylink_mac_select_pcs	= sja1105_mac_select_pcs,
 	.phylink_mac_link_up	= sja1105_mac_link_up,
 	.phylink_mac_link_down	= sja1105_mac_link_down,
 	.get_strings		= sja1105_get_strings,