amd-xgbe: Add support for a KR redriver

This patch provides support for the presence of a KR redriver chip in
between the device PCS and an external PHY.  When a redriver chip is
present the device must perform clause 73 auto-negotiation in order to
set the redriver chip for the downstream connection.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/amd/xgbe/xgbe-common.h

@@ -1062,6 +1062,16 @@
 #define XP_PROP_4_MUX_ADDR_LO_WIDTH		3
 #define XP_PROP_4_MUX_CHAN_INDEX		4
 #define XP_PROP_4_MUX_CHAN_WIDTH		3
+#define XP_PROP_4_REDRV_ADDR_INDEX		16
+#define XP_PROP_4_REDRV_ADDR_WIDTH		7
+#define XP_PROP_4_REDRV_IF_INDEX		23
+#define XP_PROP_4_REDRV_IF_WIDTH		1
+#define XP_PROP_4_REDRV_LANE_INDEX		24
+#define XP_PROP_4_REDRV_LANE_WIDTH		3
+#define XP_PROP_4_REDRV_MODEL_INDEX		28
+#define XP_PROP_4_REDRV_MODEL_WIDTH		3
+#define XP_PROP_4_REDRV_PRESENT_INDEX		31
+#define XP_PROP_4_REDRV_PRESENT_WIDTH		1
 
 /* I2C Control register offsets */
 #define IC_CON					0x0000

drivers/net/ethernet/amd/xgbe/xgbe-mdio.c

@@ -179,6 +179,7 @@ static void xgbe_an_enable_interrupts(struct xgbe_prv_data *pdata)
 {
 	switch (pdata->an_mode) {
 	case XGBE_AN_MODE_CL73:
+	case XGBE_AN_MODE_CL73_REDRV:
 		xgbe_an73_enable_interrupts(pdata);
 		break;
 	case XGBE_AN_MODE_CL37:
@@ -254,6 +255,10 @@ static void xgbe_kx_1000_mode(struct xgbe_prv_data *pdata)
 
 static void xgbe_sfi_mode(struct xgbe_prv_data *pdata)
 {
+	/* If a KR re-driver is present, change to KR mode instead */
+	if (pdata->kr_redrv)
+		return xgbe_kr_mode(pdata);
+
 	/* Disable KR training */
 	xgbe_an73_disable_kr_training(pdata);
 
@@ -433,6 +438,7 @@ static void xgbe_an_restart(struct xgbe_prv_data *pdata)
 {
 	switch (pdata->an_mode) {
 	case XGBE_AN_MODE_CL73:
+	case XGBE_AN_MODE_CL73_REDRV:
 		xgbe_an73_restart(pdata);
 		break;
 	case XGBE_AN_MODE_CL37:
@@ -448,6 +454,7 @@ static void xgbe_an_disable(struct xgbe_prv_data *pdata)
 {
 	switch (pdata->an_mode) {
 	case XGBE_AN_MODE_CL73:
+	case XGBE_AN_MODE_CL73_REDRV:
 		xgbe_an73_disable(pdata);
 		break;
 	case XGBE_AN_MODE_CL37:
@@ -687,6 +694,7 @@ static irqreturn_t xgbe_an_isr(int irq, void *data)
 
 	switch (pdata->an_mode) {
 	case XGBE_AN_MODE_CL73:
+	case XGBE_AN_MODE_CL73_REDRV:
 		xgbe_an73_isr(pdata);
 		break;
 	case XGBE_AN_MODE_CL37:
@@ -895,6 +903,7 @@ static void xgbe_an_state_machine(struct work_struct *work)
 
 	switch (pdata->an_mode) {
 	case XGBE_AN_MODE_CL73:
+	case XGBE_AN_MODE_CL73_REDRV:
 		xgbe_an73_state_machine(pdata);
 		break;
 	case XGBE_AN_MODE_CL37:
@@ -910,16 +919,18 @@ static void xgbe_an_state_machine(struct work_struct *work)
 
 static void xgbe_an37_init(struct xgbe_prv_data *pdata)
 {
-	unsigned int reg;
+	unsigned int advertising, reg;
+
+	advertising = pdata->phy_if.phy_impl.an_advertising(pdata);
 
 	/* Set up Advertisement register */
 	reg = XMDIO_READ(pdata, MDIO_MMD_VEND2, MDIO_VEND2_AN_ADVERTISE);
-	if (pdata->phy.advertising & ADVERTISED_Pause)
+	if (advertising & ADVERTISED_Pause)
 		reg |= 0x100;
 	else
 		reg &= ~0x100;
 
-	if (pdata->phy.advertising & ADVERTISED_Asym_Pause)
+	if (advertising & ADVERTISED_Asym_Pause)
 		reg |= 0x80;
 	else
 		reg &= ~0x80;
@@ -954,11 +965,13 @@ static void xgbe_an37_init(struct xgbe_prv_data *pdata)
 
 static void xgbe_an73_init(struct xgbe_prv_data *pdata)
 {
-	unsigned int reg;
+	unsigned int advertising, reg;
+
+	advertising = pdata->phy_if.phy_impl.an_advertising(pdata);
 
 	/* Set up Advertisement register 3 first */
 	reg = XMDIO_READ(pdata, MDIO_MMD_AN, MDIO_AN_ADVERTISE + 2);
-	if (pdata->phy.advertising & ADVERTISED_10000baseR_FEC)
+	if (advertising & ADVERTISED_10000baseR_FEC)
 		reg |= 0xc000;
 	else
 		reg &= ~0xc000;
@@ -967,13 +980,13 @@ static void xgbe_an73_init(struct xgbe_prv_data *pdata)
 
 	/* Set up Advertisement register 2 next */
 	reg = XMDIO_READ(pdata, MDIO_MMD_AN, MDIO_AN_ADVERTISE + 1);
-	if (pdata->phy.advertising & ADVERTISED_10000baseKR_Full)
+	if (advertising & ADVERTISED_10000baseKR_Full)
 		reg |= 0x80;
 	else
 		reg &= ~0x80;
 
-	if ((pdata->phy.advertising & ADVERTISED_1000baseKX_Full) ||
-	    (pdata->phy.advertising & ADVERTISED_2500baseX_Full))
+	if ((advertising & ADVERTISED_1000baseKX_Full) ||
+	    (advertising & ADVERTISED_2500baseX_Full))
 		reg |= 0x20;
 	else
 		reg &= ~0x20;
@@ -982,12 +995,12 @@ static void xgbe_an73_init(struct xgbe_prv_data *pdata)
 
 	/* Set up Advertisement register 1 last */
 	reg = XMDIO_READ(pdata, MDIO_MMD_AN, MDIO_AN_ADVERTISE);
-	if (pdata->phy.advertising & ADVERTISED_Pause)
+	if (advertising & ADVERTISED_Pause)
 		reg |= 0x400;
 	else
 		reg &= ~0x400;
 
-	if (pdata->phy.advertising & ADVERTISED_Asym_Pause)
+	if (advertising & ADVERTISED_Asym_Pause)
 		reg |= 0x800;
 	else
 		reg &= ~0x800;
@@ -1006,6 +1019,7 @@ static void xgbe_an_init(struct xgbe_prv_data *pdata)
 	pdata->an_mode = pdata->phy_if.phy_impl.an_mode(pdata);
 	switch (pdata->an_mode) {
 	case XGBE_AN_MODE_CL73:
+	case XGBE_AN_MODE_CL73_REDRV:
 		xgbe_an73_init(pdata);
 		break;
 	case XGBE_AN_MODE_CL37:
@@ -1149,10 +1163,15 @@ static int __xgbe_phy_config_aneg(struct xgbe_prv_data *pdata)
 	if (ret)
 		return ret;
 
-	if (pdata->phy.autoneg != AUTONEG_ENABLE)
-		return xgbe_phy_config_fixed(pdata);
+	if (pdata->phy.autoneg != AUTONEG_ENABLE) {
+		ret = xgbe_phy_config_fixed(pdata);
+		if (ret || !pdata->kr_redrv)
+			return ret;
 
+		netif_dbg(pdata, link, pdata->netdev, "AN redriver support\n");
+	} else {
 		netif_dbg(pdata, link, pdata->netdev, "AN PHY configuration\n");
+	}
 
 	/* Disable auto-negotiation interrupt */
 	disable_irq(pdata->an_irq);

drivers/net/ethernet/amd/xgbe/xgbe-phy-v1.c

@@ -295,6 +295,11 @@ static enum xgbe_mode xgbe_phy_an_outcome(struct xgbe_prv_data *pdata)
 	return mode;
 }
 
+static unsigned int xgbe_phy_an_advertising(struct xgbe_prv_data *pdata)
+{
+	return pdata->phy.advertising;
+}
+
 static int xgbe_phy_an_config(struct xgbe_prv_data *pdata)
 {
 	/* Nothing uniquely required for an configuration */
@@ -831,6 +836,8 @@ void xgbe_init_function_ptrs_phy_v1(struct xgbe_phy_if *phy_if)
 
 	phy_impl->an_config		= xgbe_phy_an_config;
 
+	phy_impl->an_advertising	= xgbe_phy_an_advertising;
+
 	phy_impl->an_outcome		= xgbe_phy_an_outcome;
 
 	phy_impl->kr_training_pre	= xgbe_phy_kr_training_pre;

drivers/net/ethernet/amd/xgbe/xgbe.h

@@ -508,6 +508,7 @@ enum xgbe_xpcs_access {
 
 enum xgbe_an_mode {
 	XGBE_AN_MODE_CL73 = 0,
+	XGBE_AN_MODE_CL73_REDRV,
 	XGBE_AN_MODE_CL37,
 	XGBE_AN_MODE_CL37_SGMII,
 	XGBE_AN_MODE_NONE,
@@ -807,6 +808,9 @@ struct xgbe_phy_impl_if {
 	/* Configure auto-negotiation settings */
 	int (*an_config)(struct xgbe_prv_data *);
 
+	/* Set/override auto-negotiation advertisement settings */
+	unsigned int (*an_advertising)(struct xgbe_prv_data *);
+
 	/* Process results of auto-negotiation */
 	enum xgbe_mode (*an_outcome)(struct xgbe_prv_data *);
 
@@ -1124,6 +1128,8 @@ struct xgbe_prv_data {
 	unsigned long link_check;
 	struct completion mdio_complete;
 
+	unsigned int kr_redrv;
+
 	char an_name[IFNAMSIZ + 32];
 	struct workqueue_struct *an_workqueue;