[RFC PATCH v2 net-next 15/15] net: pcs: lynx: use MTIP AN/LT block for copper backplanes

[Vladimir Oltean]

If the fsl,backplane-mode device tree property is present, then the Lynx
PCS makes use of the AN/LT block to advertise the supported backplane
link modes using clause 73 autoneg.

Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
---
v1->v2: code is new

 drivers/net/pcs/Kconfig    |   1 +
 drivers/net/pcs/pcs-lynx.c | 135 +++++++++++++++++++++++++++++++++++++
 2 files changed, 136 insertions(+)

diff --git a/drivers/net/pcs/Kconfig b/drivers/net/pcs/Kconfig
index 24a033e93bdd..be561c465b4a 100644
--- a/drivers/net/pcs/Kconfig
+++ b/drivers/net/pcs/Kconfig
@@ -13,6 +13,7 @@ config MTIP_BACKPLANE_PHY
 	  SoCs.
 
 config PCS_XPCS
+	depends on MTIP_BACKPLANE_PHY || MTIP_BACKPLANE_PHY=n
 	tristate
 	select PHYLINK
 	help
diff --git a/drivers/net/pcs/pcs-lynx.c b/drivers/net/pcs/pcs-lynx.c
index dc3962b2aa6b..1352f08edcf3 100644
--- a/drivers/net/pcs/pcs-lynx.c
+++ b/drivers/net/pcs/pcs-lynx.c
@@ -4,10 +4,14 @@
  */
 
 #include <linux/mdio.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
 #include <linux/phylink.h>
 #include <linux/pcs-lynx.h>
 #include <linux/property.h>
 
+#include "mtip_backplane.h"
+
 #define SGMII_CLOCK_PERIOD_NS		8 /* PCS is clocked at 125 MHz */
 #define LINK_TIMER_VAL(ns)		((u32)((ns) / SGMII_CLOCK_PERIOD_NS))
 
@@ -20,9 +24,15 @@
 #define IF_MODE_SPEED_MSK		GENMASK(3, 2)
 #define IF_MODE_HALF_DUPLEX		BIT(4)
 
+#define PRIMARY_LANE			0
+#define MAX_NUM_LANES			4
+
 struct lynx_pcs {
 	struct phylink_pcs pcs;
 	struct mdio_device *mdio;
+	struct mtip_backplane *anlt[MAX_NUM_LANES];
+	int num_lanes;
+	bool backplane_mode;
 };
 
 enum sgmii_speed {
@@ -100,6 +110,9 @@ static void lynx_pcs_get_state(struct phylink_pcs *pcs,
 	case PHY_INTERFACE_MODE_10GBASER:
 		phylink_mii_c45_pcs_get_state(lynx->mdio, state);
 		break;
+	case PHY_INTERFACE_MODE_INTERNAL:
+		mtip_backplane_get_state(lynx->anlt[PRIMARY_LANE], state);
+		break;
 	default:
 		break;
 	}
@@ -168,6 +181,17 @@ static int lynx_pcs_config_usxgmii(struct mdio_device *pcs,
 				 ADVERTISE_SGMII | ADVERTISE_LPACK);
 }
 
+static int lynx_pcs_config_backplane(struct phylink_pcs *pcs,
+				     unsigned int neg_mode,
+				     const unsigned long *advertising)
+{
+	bool autoneg = neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED;
+	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
+
+	return mtip_backplane_config_aneg(lynx->anlt[PRIMARY_LANE], autoneg,
+					  advertising);
+}
+
 static int lynx_pcs_config(struct phylink_pcs *pcs, unsigned int neg_mode,
 			   phy_interface_t ifmode,
 			   const unsigned long *advertising, bool permit)
@@ -193,6 +217,8 @@ static int lynx_pcs_config(struct phylink_pcs *pcs, unsigned int neg_mode,
 	case PHY_INTERFACE_MODE_10GBASER:
 		/* Nothing to do here for 10GBASER */
 		break;
+	case PHY_INTERFACE_MODE_INTERNAL:
+		return lynx_pcs_config_backplane(pcs, neg_mode, advertising);
 	default:
 		return -EOPNOTSUPP;
 	}
@@ -204,6 +230,9 @@ static void lynx_pcs_an_restart(struct phylink_pcs *pcs)
 {
 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
 
+	if (lynx->backplane_mode)
+		return mtip_backplane_an_restart(lynx->anlt[PRIMARY_LANE]);
+
 	phylink_mii_c22_pcs_an_restart(lynx->mdio);
 }
 
@@ -306,16 +335,111 @@ static void lynx_pcs_link_up(struct phylink_pcs *pcs, unsigned int neg_mode,
 	}
 }
 
+static int lynx_pcs_validate(struct phylink_pcs *pcs, unsigned long *supported,
+			     const struct phylink_link_state *state)
+{
+	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
+
+	if (state->interface != PHY_INTERFACE_MODE_INTERNAL)
+		return 0;
+
+	return mtip_backplane_validate(lynx->anlt[PRIMARY_LANE], supported);
+}
+
+static int lynx_pcs_enable(struct phylink_pcs *pcs)
+{
+	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
+	int err;
+
+	if (lynx->backplane_mode) {
+		err = mtip_backplane_resume(lynx->anlt[PRIMARY_LANE]);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static void lynx_pcs_disable(struct phylink_pcs *pcs)
+{
+	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
+
+	if (lynx->backplane_mode)
+		mtip_backplane_suspend(lynx->anlt[PRIMARY_LANE]);
+}
+
 static const struct phylink_pcs_ops lynx_pcs_phylink_ops = {
 	.pcs_get_state = lynx_pcs_get_state,
 	.pcs_config = lynx_pcs_config,
 	.pcs_an_restart = lynx_pcs_an_restart,
 	.pcs_link_up = lynx_pcs_link_up,
+	.pcs_validate = lynx_pcs_validate,
+	.pcs_enable = lynx_pcs_enable,
+	.pcs_disable = lynx_pcs_disable,
 };
 
+static int lynx_pcs_parse_fwnode(struct lynx_pcs *lynx)
+{
+	struct fwnode_handle *node = lynx->mdio->dev.fwnode;
+	enum mtip_model model = MTIP_MODEL_AUTODETECT;
+	struct device_node *np = to_of_node(node);
+	struct mdio_device *mdio = lynx->mdio;
+	struct device *dev = &mdio->dev;
+	struct phy *phy;
+	int i, err;
+
+	if (!node)
+		return 0;
+
+	lynx->backplane_mode = fwnode_property_present(node, "fsl,backplane-mode");
+	if (!lynx->backplane_mode)
+		return 0;
+
+	if (fwnode_device_is_compatible(node, "fsl,lx2160a-lynx-pcs"))
+		model = MTIP_MODEL_LX2160A;
+
+	lynx->num_lanes = of_count_phandle_with_args(np, "phys", "#phy-cells");
+	if (lynx->num_lanes < 0)
+		return lynx->num_lanes;
+
+	if (WARN_ON(lynx->num_lanes > MAX_NUM_LANES))
+		return -EINVAL;
+
+	for (i = 0; i < lynx->num_lanes; i++) {
+		phy = devm_of_phy_get_by_index(dev, np, i);
+		if (IS_ERR(phy))
+			return dev_err_probe(dev, PTR_ERR(phy),
+					     "Failed to get SerDes PHY %d\n", i);
+
+		lynx->anlt[i] = mtip_backplane_create(mdio, phy, model);
+		if (IS_ERR(lynx->anlt[i])) {
+			err = PTR_ERR(lynx->anlt[i]);
+
+			while (i-- > 0)
+				mtip_backplane_destroy(lynx->anlt[i]);
+
+			return err;
+		}
+	}
+
+	for (i = 1; i < lynx->num_lanes; i++) {
+		err = mtip_backplane_add_subordinate(lynx->anlt[PRIMARY_LANE],
+						     lynx->anlt[i]);
+		if (WARN_ON(err)) {
+			/* Too many SerDes lanes in the device tree? */
+			for (i = 0; i < lynx->num_lanes; i++)
+				mtip_backplane_destroy(lynx->anlt[i]);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
 static struct phylink_pcs *lynx_pcs_create(struct mdio_device *mdio)
 {
 	struct lynx_pcs *lynx;
+	int err;
 
 	lynx = kzalloc(sizeof(*lynx), GFP_KERNEL);
 	if (!lynx)
@@ -327,6 +451,12 @@ static struct phylink_pcs *lynx_pcs_create(struct mdio_device *mdio)
 	lynx->pcs.neg_mode = true;
 	lynx->pcs.poll = true;
 
+	err = lynx_pcs_parse_fwnode(lynx);
+	if (err) {
+		kfree(lynx);
+		return ERR_PTR(err);
+	}
+
 	return lynx_to_phylink_pcs(lynx);
 }
 
@@ -392,6 +522,11 @@ EXPORT_SYMBOL_GPL(lynx_pcs_create_fwnode);
 void lynx_pcs_destroy(struct phylink_pcs *pcs)
 {
 	struct lynx_pcs *lynx = phylink_pcs_to_lynx(pcs);
+	int i;
+
+	if (lynx->backplane_mode)
+		for (i = 0; i < lynx->num_lanes; i++)
+			mtip_backplane_destroy(lynx->anlt[i]);
 
 	mdio_device_put(lynx->mdio);
 	kfree(lynx);
-- 
2.34.1