net: phylink: add pcs_validate() method

Add a hook for PCS to validate the link parameters. This avoids MAC
drivers having to have knowledge of their PCS in their validate()
method, thereby allowing several MAC drivers to be simplfied.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 31 insertions, 0 deletions

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index c7035d65e159..420201858564 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -424,13 +424,44 @@ static int phylink_validate_mac_and_pcs(struct phylink *pl,
 					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;