Merge branch 'phylink-pcs-validation'

Russell King says:

====================
net: phylink: add PCS validation

This series allows phylink to include the PCS in its validation step.
There are two reasons to make this change:

1. Some of the network drivers that are making use of the split PCS
   support are already manually calling into their PCS drivers to
   perform validation. E.g. stmmac with xpcs.

2. Logically, some network drivers such as mvneta and mvpp2, the
   restriction we impose in the validate() callback is a property of
   the "PCS" block that we provide rather than the MAC.

This series:

1. Gives phylink a mechanism to query the MAC driver which PCS is
   wishes to use for the PHY interface mode. This is necessary to allow
   the PCS to be involved in the validation step without making changes
   to the configuration.

2. Provide a pcs_validate() method that PCS can implement. This follows
   a similar model to the MAC's validate() callback, but with some minor
   differences due to observations from the various implementations.
   E.g. returning an error code for not-supported and the way the
   advertising bitmap is masked.

3. Convert mvpp2 and mvneta to this as examples of its use. Further
   Conversions are in the pipeline, including for stmmac+xpcs, as well
   as some DSA drivers. Note that DSA conversion to this is conditional
   upon all DSA drivers populating their supported_interfaces bitmap,
   since this is required before mac_select_pcs() can be used.

Existing drivers that set a PCS in mac_prepare() or mac_config(), or
shortly after phylink_create() will continue to work. However, it should
be noted that mac_select_pcs() will be called during phylink_create(),
and thus any PCS returned by mac_select_pcs() must be available by this
time - or we drop the check in phylink_create().

v2: fix kerneldoc typo in patch 1.
====================

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

1 files changed, 38 insertions, 0 deletions

diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index a2f266cc3442..713a0c928b7c 100644
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -112,6 +112,7 @@ struct phylink_config {
 /**
  * struct phylink_mac_ops - MAC operations structure.
  * @validate: Validate and update the link configuration.
+ * @mac_select_pcs: Select a PCS for the interface mode.
  * @mac_pcs_get_state: Read the current link state from the hardware.
  * @mac_prepare: prepare for a major reconfiguration of the interface.
  * @mac_config: configure the MAC for the selected mode and state.
@@ -126,6 +127,8 @@ struct phylink_mac_ops {
 	void (*validate)(struct phylink_config *config,
 			 unsigned long *supported,
 			 struct phylink_link_state *state);
+	struct phylink_pcs *(*mac_select_pcs)(struct phylink_config *config,
+					      phy_interface_t interface);
 	void (*mac_pcs_get_state)(struct phylink_config *config,
 				  struct phylink_link_state *state);
 	int (*mac_prepare)(struct phylink_config *config, unsigned int mode,
@@ -178,6 +181,21 @@ struct phylink_mac_ops {
  */
 void validate(struct phylink_config *config, unsigned long *supported,
 	      struct phylink_link_state *state);
+/**
+ * mac_select_pcs: Select a PCS for the interface mode.
+ * @config: a pointer to a &struct phylink_config.
+ * @interface: PHY interface mode for PCS
+ *
+ * Return the &struct phylink_pcs for the specified interface mode, or
+ * NULL if none is required, or an error pointer on error.
+ *
+ * This must not modify any state. It is used to query which PCS should
+ * be used. Phylink will use this during validation to ensure that the
+ * configuration is valid, and when setting a configuration to internally
+ * set the PCS that will be used.
+ */
+struct phylink_pcs *mac_select_pcs(struct phylink_config *config,
+				   phy_interface_t interface);
 
 /**
  * mac_pcs_get_state() - Read the current inband link state from the hardware
@@ -398,6 +416,7 @@ struct phylink_pcs {
 
 /**
  * struct phylink_pcs_ops - MAC PCS operations structure.
+ * @pcs_validate: validate the link configuration.
  * @pcs_get_state: read the current MAC PCS link state from the hardware.
  * @pcs_config: configure the MAC PCS for the selected mode and state.
  * @pcs_an_restart: restart 802.3z BaseX autonegotiation.
@@ -405,6 +424,8 @@ struct phylink_pcs {
  *               (where necessary).
  */
 struct phylink_pcs_ops {
+	int (*pcs_validate)(struct phylink_pcs *pcs, unsigned long *supported,
+			    const struct phylink_link_state *state);
 	void (*pcs_get_state)(struct phylink_pcs *pcs,
 			      struct phylink_link_state *state);
 	int (*pcs_config)(struct phylink_pcs *pcs, unsigned int mode,
@@ -418,6 +439,23 @@ struct phylink_pcs_ops {
 
 #if 0 /* For kernel-doc purposes only. */
 /**
+ * pcs_validate() - validate the link configuration.
+ * @pcs: a pointer to a &struct phylink_pcs.
+ * @supported: ethtool bitmask for supported link modes.
+ * @state: a const pointer to a &struct phylink_link_state.
+ *
+ * Validate the interface mode, and advertising's autoneg bit, removing any
+ * media ethtool link modes that would not be supportable from the supported
+ * mask. Phylink will propagate the changes to the advertising mask. See the
+ * &struct phylink_mac_ops validate() method.
+ *
+ * Returns -EINVAL if the interface mode/autoneg mode is not supported.
+ * Returns non-zero positive if the link state can be supported.
+ */
+int pcs_validate(struct phylink_pcs *pcs, unsigned long *supported,
+		 const struct phylink_link_state *state);
+
+/**
  * pcs_get_state() - Read the current inband link state from the hardware
  * @pcs: a pointer to a &struct phylink_pcs.
  * @state: a pointer to a &struct phylink_link_state.