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, 90 insertions, 9 deletions

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 20df8af3e201..420201858564 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -419,6 +419,54 @@ void phylink_generic_validate(struct phylink_config *config,
 }
 EXPORT_SYMBOL_GPL(phylink_generic_validate);
 
+static int phylink_validate_mac_and_pcs(struct phylink *pl,
+					unsigned long *supported,
+					struct phylink_link_state *state)
+{
+	struct phylink_pcs *pcs;
+	int ret;
+
+	/* Get the PCS for this interface mode */
+	if (pl->mac_ops->mac_select_pcs) {
+		pcs = pl->mac_ops->mac_select_pcs(pl->config, state->interface);
+		if (IS_ERR(pcs))
+			return PTR_ERR(pcs);
+	} else {
+		pcs = pl->pcs;
+	}
+
+	if (pcs) {
+		/* The PCS, if present, must be setup before phylink_create()
+		 * has been called. If the ops is not initialised, print an
+		 * error and backtrace rather than oopsing the kernel.
+		 */
+		if (!pcs->ops) {
+			phylink_err(pl, "interface %s: uninitialised PCS\n",
+				    phy_modes(state->interface));
+			dump_stack();
+			return -EINVAL;
+		}
+
+		/* Validate the link parameters with the PCS */
+		if (pcs->ops->pcs_validate) {
+			ret = pcs->ops->pcs_validate(pcs, supported, state);
+			if (ret < 0 || phylink_is_empty_linkmode(supported))
+				return -EINVAL;
+
+			/* Ensure the advertising mask is a subset of the
+			 * supported mask.
+			 */
+			linkmode_and(state->advertising, state->advertising,
+				     supported);
+		}
+	}
+
+	/* Then validate the link parameters with the MAC */
+	pl->mac_ops->validate(pl->config, supported, state);
+
+	return phylink_is_empty_linkmode(supported) ? -EINVAL : 0;
+}
+
 static int phylink_validate_any(struct phylink *pl, unsigned long *supported,
 				struct phylink_link_state *state)
 {
@@ -434,9 +482,10 @@ static int phylink_validate_any(struct phylink *pl, unsigned long *supported,
 
 			t = *state;
 			t.interface = intf;
-			pl->mac_ops->validate(pl->config, s, &t);
-			linkmode_or(all_s, all_s, s);
-			linkmode_or(all_adv, all_adv, t.advertising);
+			if (!phylink_validate_mac_and_pcs(pl, s, &t)) {
+				linkmode_or(all_s, all_s, s);
+				linkmode_or(all_adv, all_adv, t.advertising);
+			}
 		}
 	}
 
@@ -458,9 +507,7 @@ static int phylink_validate(struct phylink *pl, unsigned long *supported,
 			return -EINVAL;
 	}
 
-	pl->mac_ops->validate(pl->config, supported, state);
-
-	return phylink_is_empty_linkmode(supported) ? -EINVAL : 0;
+	return phylink_validate_mac_and_pcs(pl, supported, state);
 }
 
 static int phylink_parse_fixedlink(struct phylink *pl,
@@ -750,10 +797,21 @@ static void phylink_mac_pcs_an_restart(struct phylink *pl)
 static void phylink_major_config(struct phylink *pl, bool restart,
 				  const struct phylink_link_state *state)
 {
+	struct phylink_pcs *pcs = NULL;
 	int err;
 
 	phylink_dbg(pl, "major config %s\n", phy_modes(state->interface));
 
+	if (pl->mac_ops->mac_select_pcs) {
+		pcs = pl->mac_ops->mac_select_pcs(pl->config, state->interface);
+		if (IS_ERR(pcs)) {
+			phylink_err(pl,
+				    "mac_select_pcs unexpectedly failed: %pe\n",
+				    pcs);
+			return;
+		}
+	}
+
 	if (pl->mac_ops->mac_prepare) {
 		err = pl->mac_ops->mac_prepare(pl->config, pl->cur_link_an_mode,
 					       state->interface);
@@ -764,6 +822,12 @@ static void phylink_major_config(struct phylink *pl, bool restart,
 		}
 	}
 
+	/* If we have a new PCS, switch to the new PCS after preparing the MAC
+	 * for the change.
+	 */
+	if (pcs)
+		phylink_set_pcs(pl, pcs);
+
 	phylink_mac_config(pl, state);
 
 	if (pl->pcs_ops) {
@@ -1155,6 +1219,14 @@ struct phylink *phylink_create(struct phylink_config *config,
 	struct phylink *pl;
 	int ret;
 
+	/* Validate the supplied configuration */
+	if (mac_ops->mac_select_pcs &&
+	    phy_interface_empty(config->supported_interfaces)) {
+		dev_err(config->dev,
+			"phylink: error: empty supported_interfaces but mac_select_pcs() method present\n");
+		return ERR_PTR(-EINVAL);
+	}
+
 	pl = kzalloc(sizeof(*pl), GFP_KERNEL);
 	if (!pl)
 		return ERR_PTR(-ENOMEM);
@@ -1222,9 +1294,10 @@ EXPORT_SYMBOL_GPL(phylink_create);
  * @pl: a pointer to a &struct phylink returned from phylink_create()
  * @pcs: a pointer to the &struct phylink_pcs
  *
- * Bind the MAC PCS to phylink.  This may be called after phylink_create(),
- * in mac_prepare() or mac_config() methods if it is desired to dynamically
- * change the PCS.
+ * Bind the MAC PCS to phylink.  This may be called after phylink_create().
+ * If it is desired to dynamically change the PCS, then the preferred method
+ * is to use mac_select_pcs(), but it may also be called in mac_prepare()
+ * or mac_config().
  *
  * Please note that there are behavioural changes with the mac_config()
  * callback if a PCS is present (denoting a newer setup) so removing a PCS
@@ -1235,6 +1308,14 @@ void phylink_set_pcs(struct phylink *pl, struct phylink_pcs *pcs)
 {
 	pl->pcs = pcs;
 	pl->pcs_ops = pcs->ops;
+
+	if (!pl->phylink_disable_state &&
+	    pl->cfg_link_an_mode == MLO_AN_INBAND) {
+		if (pl->config->pcs_poll || pcs->poll)
+			mod_timer(&pl->link_poll, jiffies + HZ);
+		else
+			del_timer(&pl->link_poll);
+	}
 }
 EXPORT_SYMBOL_GPL(phylink_set_pcs);