net: phylink: add phylink managed MAC Wake-on-Lan support

Add core phylink managed Wake-on-Lan support, which is enabled when the
MAC driver fills in the new .mac_wol_set() method that this commit
creates.

When this feature is disabled, phylink acts as it has in the past,
merely passing the ethtool WoL calls to phylib whenever a PHY exists.
No other new functionality provided by this commit is enabled.

When this feature is enabled, a more inteligent approach is used.
Phylink will first pass WoL options to the PHY, read them back, and
attempt to set any options that were not set at the PHY at the MAC.

Since we have PHY drivers that report they support WoL, and accept WoL
configuration even though they aren't wired up to be capable of waking
the system, we need a way to differentiate between PHYs that think
they support WoL and those which actually do. As PHY drivers do not
make use of the driver model's wake-up infrastructure, but could, we
use this to determine whether PHY drivers can participate. This gives
a path forward where, as MAC drivers are converted to this, it
encourages PHY drivers to also be converted.

Phylink will also ignore the mac_wol argument to phylink_suspend() as
it now knows the WoL state at the MAC.

MAC drivers are expected to record/configure the Wake-on-Lan state in
their .mac_set_wol() method, and deal appropriately with it in their
suspend/resume methods. The driver model provides assistance to set the
IRQ wake support which may assist driver authors in achieving the
necessary configuration.

Signed-off-by: Russell King (Oracle) <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/phy/phylink.c

···
 	u8 sfp_port;
 
 	struct eee_config eee_cfg;
+
+	u32 wolopts_mac;
+	u8 wol_sopass[SOPASS_MAX];
 };
 
 #define phylink_printk(level, pl, fmt, ...) \
···
 }
 EXPORT_SYMBOL_GPL(phylink_rx_clk_stop_unblock);
 
+static bool phylink_mac_supports_wol(struct phylink *pl)
+{
+	return !!pl->mac_ops->mac_wol_set;
+}
+
+static bool phylink_phy_supports_wol(struct phylink *pl,
+				     struct phy_device *phydev)
+{
+	return phydev && (pl->config->wol_phy_legacy || phy_can_wakeup(phydev));
+}
+
 /**
  * phylink_suspend() - handle a network device suspend event
  * @pl: a pointer to a &struct phylink returned from phylink_create()
···
  *   can also bring down the link between the MAC and PHY.
  * - If Wake-on-Lan is active, but being handled by the MAC, the MAC
  *   still needs to receive packets, so we can not bring the link down.
+ *
+ * Note: when phylink managed Wake-on-Lan is in use, @mac_wol is ignored.
+ * (struct phylink_mac_ops.mac_set_wol populated.)
  */
 void phylink_suspend(struct phylink *pl, bool mac_wol)
 {
 	ASSERT_RTNL();
+
+	if (phylink_mac_supports_wol(pl))
+		mac_wol = !!pl->wolopts_mac;
 
 	if (mac_wol && (!pl->netdev || pl->netdev->ethtool->wol_enabled)) {
 		/* Wake-on-Lan enabled, MAC handling */
···
 	wol->supported = 0;
 	wol->wolopts = 0;
 
-	if (pl->phydev)
-		phy_ethtool_get_wol(pl->phydev, wol);
+	if (phylink_mac_supports_wol(pl)) {
+		if (phylink_phy_supports_wol(pl, pl->phydev))
+			phy_ethtool_get_wol(pl->phydev, wol);
+
+		/* Where the MAC augments the WoL support, merge its support and
+		 * current configuration.
+		 */
+		if (~wol->wolopts & pl->wolopts_mac & WAKE_MAGICSECURE)
+			memcpy(wol->sopass, pl->wol_sopass,
+			       sizeof(wol->sopass));
+
+		wol->supported |= pl->config->wol_mac_support;
+		wol->wolopts |= pl->wolopts_mac;
+	} else {
+		/* Legacy */
+		if (pl->phydev)
+			phy_ethtool_get_wol(pl->phydev, wol);
+	}
 }
 EXPORT_SYMBOL_GPL(phylink_ethtool_get_wol);
 
···
  */
 int phylink_ethtool_set_wol(struct phylink *pl, struct ethtool_wolinfo *wol)
 {
+	struct ethtool_wolinfo w = { .cmd = ETHTOOL_GWOL };
 	int ret = -EOPNOTSUPP;
+	bool changed;
+	u32 wolopts;
 
 	ASSERT_RTNL();
 
-	if (pl->phydev)
-		ret = phy_ethtool_set_wol(pl->phydev, wol);
+	if (phylink_mac_supports_wol(pl)) {
+		wolopts = wol->wolopts;
+
+		if (phylink_phy_supports_wol(pl, pl->phydev)) {
+			ret = phy_ethtool_set_wol(pl->phydev, wol);
+			if (ret != 0 && ret != -EOPNOTSUPP)
+				return ret;
+
+			phy_ethtool_get_wol(pl->phydev, &w);
+
+			/* Any Wake-on-Lan modes which the PHY is handling
+			 * should not be passed on to the MAC.
+			 */
+			wolopts &= ~w.wolopts;
+		}
+
+		wolopts &= pl->config->wol_mac_support;
+		changed = pl->wolopts_mac != wolopts;
+		if (wolopts & WAKE_MAGICSECURE)
+			changed |= !!memcmp(wol->sopass, pl->wol_sopass,
+					    sizeof(wol->sopass));
+		memcpy(pl->wol_sopass, wol->sopass, sizeof(pl->wol_sopass));
+
+		if (changed) {
+			ret = pl->mac_ops->mac_wol_set(pl->config, wolopts,
+						       wol->sopass);
+			if (!ret)
+				pl->wolopts_mac = wolopts;
+		} else {
+			ret = 0;
+		}
+	} else {
+		if (pl->phydev)
+			ret = phy_ethtool_set_wol(pl->phydev, wol);
+	}
 
 	return ret;
 }

include/linux/phylink.h

···
  * @lpi_capabilities: MAC speeds which can support LPI signalling
  * @lpi_timer_default: Default EEE LPI timer setting.
  * @eee_enabled_default: If set, EEE will be enabled by phylink at creation time
+ * @wol_phy_legacy: Use Wake-on-Lan with PHY even if phy_can_wakeup() is false
+ * @wol_mac_support: Bitmask of MAC supported %WAKE_* options
  */
 struct phylink_config {
 	struct device *dev;
···
 	unsigned long lpi_capabilities;
 	u32 lpi_timer_default;
 	bool eee_enabled_default;
+
+	/* Wake-on-Lan support */
+	bool wol_phy_legacy;
+	u32 wol_mac_support;
 };
 
 void phylink_limit_mac_speed(struct phylink_config *config, u32 max_speed);
···
  * @mac_link_up: allow the link to come up.
  * @mac_disable_tx_lpi: disable LPI.
  * @mac_enable_tx_lpi: enable and configure LPI.
+ * @mac_wol_set: configure Wake-on-Lan settings at the MAC.
  *
  * The individual methods are described more fully below.
  */
···
 	void (*mac_disable_tx_lpi)(struct phylink_config *config);
 	int (*mac_enable_tx_lpi)(struct phylink_config *config, u32 timer,
 				 bool tx_clk_stop);
+
+	int (*mac_wol_set)(struct phylink_config *config, u32 wolopts,
+			   const u8 *sopass);
 };
 
 #if 0 /* For kernel-doc purposes only. */
···
  */
 int mac_enable_tx_lpi(struct phylink_config *config, u32 timer,
 		      bool tx_clk_stop);
+
+/**
+ * mac_wol_set() - configure the Wake-on-Lan parameters
+ * @config: a pointer to a &struct phylink_config.
+ * @wolopts: Bitmask of %WAKE_* flags for enabled Wake-On-Lan modes.
+ * @sopass: SecureOn(tm) password; meaningful only for %WAKE_MAGICSECURE
+ *
+ * Enable the specified Wake-on-Lan options at the MAC. Options that the
+ * PHY can handle will have been removed from @wolopts.
+ *
+ * The presence of this method enables phylink-managed WoL support.
+ *
+ * Returns: 0 on success.
+ */
+int (*mac_wol_set)(struct phylink_config *config, u32 wolopts,
+		   const u8 *sopass);
 #endif
 
 struct phylink_pcs_ops;