[PATCH v2 09/11] [RFC] net: phylink: Add support for CRS-based rate adaptation

[Sean Anderson]

This adds support for CRS-based rate adaptation, such as the type used
for 10PASS-TS and 2BASE-TL. As these link modes are not supported by any
in-tree phy, this patch is marked as RFC. It serves chiefly to
illustrate the approach to adding support for another rate adaptation
type.

Signed-off-by: Sean Anderson <sean.anderson@xxxxxxxx>
---

(no changes since v1)

 drivers/net/phy/phylink.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index f61040c93f3c..75b4994d68c8 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -553,9 +553,18 @@ unsigned long phylink_get_capabilities(phy_interface_t interface,
 		adapted_caps &= ~(MAC_1000HD | MAC_100HD | MAC_10HD);
 		break;
 	}
-	case RATE_ADAPT_CRS:
-		/* TODO */
+	case RATE_ADAPT_CRS: {
+		/* The MAC must support half duplex at the interface speed */
+		if (state.speed == SPEED_1000) {
+			if (mac_capabilities & MAC_1000HD)
+				adapted_caps = MAC_100 | MAC_10;
+		} else if (state.speed == SPEED_1000) {
+			if (mac_capabilities & MAC_100HD)
+				adapted_caps = MAC_10;
+		}
+		adapted_caps &= mac_capabilities;
 		break;
+	}
 	case RATE_ADAPT_OPEN_LOOP:
 		/* TODO */
 		break;
-- 
2.35.1.1320.gc452695387.dirty