net: phylink: provide phylink_validate_mask_caps() helper

Provide a helper that restricts the link modes according to the
phylink capabilities.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
[rebased on net-next/master and added documentation]
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/phylink.c

@@ -562,31 +562,48 @@ unsigned long phylink_get_capabilities(phy_interface_t interface,
 EXPORT_SYMBOL_GPL(phylink_get_capabilities);
 
 /**
- * phylink_generic_validate() - generic validate() callback implementation
- * @config: a pointer to a &struct phylink_config.
+ * phylink_validate_mask_caps() - Restrict link modes based on caps
  * @supported: ethtool bitmask for supported link modes.
- * @state: a pointer to a &struct phylink_link_state.
+ * @state: an (optional) pointer to a &struct phylink_link_state.
+ * @mac_capabilities: bitmask of MAC capabilities
  *
- * Generic implementation of the validate() callback that MAC drivers can
- * use when they pass the range of supported interfaces and MAC capabilities.
- * This makes use of phylink_get_linkmodes().
+ * Calculate the supported link modes based on @mac_capabilities, and restrict
+ * @supported and @state based on that. Use this function if your capabiliies
+ * aren't constant, such as if they vary depending on the interface.
  */
-void phylink_generic_validate(struct phylink_config *config,
-			      unsigned long *supported,
-			      struct phylink_link_state *state)
+void phylink_validate_mask_caps(unsigned long *supported,
+				struct phylink_link_state *state,
+				unsigned long mac_capabilities)
 {
 	__ETHTOOL_DECLARE_LINK_MODE_MASK(mask) = { 0, };
 	unsigned long caps;
 
 	phylink_set_port_modes(mask);
 	phylink_set(mask, Autoneg);
-	caps = phylink_get_capabilities(state->interface,
-					config->mac_capabilities,
+	caps = phylink_get_capabilities(state->interface, mac_capabilities,
 					state->rate_matching);
 	phylink_caps_to_linkmodes(mask, caps);
 
 	linkmode_and(supported, supported, mask);
-	linkmode_and(state->advertising, state->advertising, mask);
+	if (state)
+		linkmode_and(state->advertising, state->advertising, mask);
+}
+EXPORT_SYMBOL_GPL(phylink_validate_mask_caps);
+
+/**
+ * phylink_generic_validate() - generic validate() callback implementation
+ * @config: a pointer to a &struct phylink_config.
+ * @supported: ethtool bitmask for supported link modes.
+ * @state: a pointer to a &struct phylink_link_state.
+ *
+ * Generic implementation of the validate() callback that MAC drivers can
+ * use when they pass the range of supported interfaces and MAC capabilities.
+ */
+void phylink_generic_validate(struct phylink_config *config,
+			      unsigned long *supported,
+			      struct phylink_link_state *state)
+{
+	phylink_validate_mask_caps(supported, state, config->mac_capabilities);
 }
 EXPORT_SYMBOL_GPL(phylink_generic_validate);
 

include/linux/phylink.h

@@ -556,6 +556,9 @@ void phylink_caps_to_linkmodes(unsigned long *linkmodes, unsigned long caps);
 unsigned long phylink_get_capabilities(phy_interface_t interface,
 				       unsigned long mac_capabilities,
 				       int rate_matching);
+void phylink_validate_mask_caps(unsigned long *supported,
+				struct phylink_link_state *state,
+				unsigned long caps);
 void phylink_generic_validate(struct phylink_config *config,
 			      unsigned long *supported,
 			      struct phylink_link_state *state);