[PATCH net-next 10/10] net: dsa: mv88e6xxx: fully support SERDES on Topaz family

["Marek Behún" <marek.behun@nic.cz>]

Currently we support SERDES on the Topaz family in a limited way: no
IRQs and the cmode is not writable, thus the mode is determined by
strapping pins.

Marvell's examples though show how to make cmode writable on port 5 and
support SGMII autonegotiation. It is done by writing hidden registers,
for which we already have code.

This patch adds support for making the cmode for the SERDES port
writable on the Topaz family, and enables cmode setting and SERDES IRQs.

Tested on Turris Mox.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
---
 drivers/net/dsa/mv88e6xxx/chip.c |  6 +++
 drivers/net/dsa/mv88e6xxx/port.c | 77 +++++++++++++++++++++++++-------
 drivers/net/dsa/mv88e6xxx/port.h |  2 +
 3 files changed, 70 insertions(+), 15 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 9af6f3aeb83b..cdd2f47fb5d0 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -2914,6 +2914,7 @@ static const struct mv88e6xxx_ops mv88e6141_ops = {
 	.port_disable_pri_override = mv88e6xxx_port_disable_pri_override,
 	.port_link_state = mv88e6352_port_link_state,
 	.port_get_cmode = mv88e6352_port_get_cmode,
+	.port_set_cmode = mv88e6341_port_set_cmode,
 	.port_setup_message_port = mv88e6xxx_setup_message_port,
 	.stats_snapshot = mv88e6390_g1_stats_snapshot,
 	.stats_set_histogram = mv88e6095_g1_stats_set_histogram,
@@ -2930,6 +2931,8 @@ static const struct mv88e6xxx_ops mv88e6141_ops = {
 	.vtu_loadpurge = mv88e6352_g1_vtu_loadpurge,
 	.serdes_power = mv88e6390_serdes_power,
 	.serdes_get_lane = mv88e6341_serdes_get_lane,
+	.serdes_irq_setup = mv88e6390_serdes_irq_setup,
+	.serdes_irq_free = mv88e6390_serdes_irq_free,
 	.gpio_ops = &mv88e6352_gpio_ops,
 	.phylink_validate = mv88e6341_phylink_validate,
 };
@@ -3609,6 +3612,7 @@ static const struct mv88e6xxx_ops mv88e6341_ops = {
 	.port_disable_pri_override = mv88e6xxx_port_disable_pri_override,
 	.port_link_state = mv88e6352_port_link_state,
 	.port_get_cmode = mv88e6352_port_get_cmode,
+	.port_set_cmode = mv88e6341_port_set_cmode,
 	.port_setup_message_port = mv88e6xxx_setup_message_port,
 	.stats_snapshot = mv88e6390_g1_stats_snapshot,
 	.stats_set_histogram = mv88e6095_g1_stats_set_histogram,
@@ -3625,6 +3629,8 @@ static const struct mv88e6xxx_ops mv88e6341_ops = {
 	.vtu_loadpurge = mv88e6352_g1_vtu_loadpurge,
 	.serdes_power = mv88e6390_serdes_power,
 	.serdes_get_lane = mv88e6341_serdes_get_lane,
+	.serdes_irq_setup = mv88e6390_serdes_irq_setup,
+	.serdes_irq_free = mv88e6390_serdes_irq_free,
 	.gpio_ops = &mv88e6352_gpio_ops,
 	.avb_ops = &mv88e6390_avb_ops,
 	.ptp_ops = &mv88e6352_ptp_ops,
diff --git a/drivers/net/dsa/mv88e6xxx/port.c b/drivers/net/dsa/mv88e6xxx/port.c
index 815a7371977b..728e4f444f6f 100644
--- a/drivers/net/dsa/mv88e6xxx/port.c
+++ b/drivers/net/dsa/mv88e6xxx/port.c
@@ -14,6 +14,7 @@
 #include <linux/phylink.h>
 
 #include "chip.h"
+#include "hidden.h"
 #include "port.h"
 #include "serdes.h"
 
@@ -392,17 +393,37 @@ phy_interface_t mv88e6390x_port_max_speed_mode(int port)
 	return PHY_INTERFACE_MODE_NA;
 }
 
-int mv88e6390x_port_set_cmode(struct mv88e6xxx_chip *chip, int port,
-			      phy_interface_t mode)
+static int mv88e6341_port_force_writable_cmode(struct mv88e6xxx_chip *chip,
+					       int port)
+{
+	int err, addr;
+	u16 reg, bits;
+
+	addr = chip->info->port_base_addr + port;
+
+	err = mv88e6390_hidden_read(chip, 0x7, addr, 0, &reg);
+	if (err)
+		return err;
+
+	bits = MV88E6341_PORT_RESERVED_1A_FORCE_CMODE |
+	       MV88E6341_PORT_RESERVED_1A_SGMII_AN;
+
+	if ((reg & bits) == bits)
+		return 0;
+
+	reg |= bits;
+	return mv88e6390_hidden_write(chip, 0x7, addr, 0, reg);
+}
+
+static int mv88e6xxx_port_set_cmode(struct mv88e6xxx_chip *chip, int port,
+				    phy_interface_t mode, bool allow_over_2500,
+				    bool make_cmode_writable)
 {
 	int lane;
 	u16 cmode;
 	u16 reg;
 	int err;
 
-	if (port != 9 && port != 10)
-		return -EOPNOTSUPP;
-
 	/* Default to a slow mode, so freeing up SERDES interfaces for
 	 * other ports which might use them for SFPs.
 	 */
@@ -421,9 +442,13 @@ int mv88e6390x_port_set_cmode(struct mv88e6xxx_chip *chip, int port,
 		break;
 	case PHY_INTERFACE_MODE_XGMII:
 	case PHY_INTERFACE_MODE_XAUI:
+		if (!allow_over_2500)
+			return -EINVAL;
 		cmode = MV88E6XXX_PORT_STS_CMODE_XAUI;
 		break;
 	case PHY_INTERFACE_MODE_RXAUI:
+		if (!allow_over_2500)
+			return -EINVAL;
 		cmode = MV88E6XXX_PORT_STS_CMODE_RXAUI;
 		break;
 	default:
@@ -457,6 +482,12 @@ int mv88e6390x_port_set_cmode(struct mv88e6xxx_chip *chip, int port,
 		if (err)
 			return err;
 
+		if (make_cmode_writable) {
+			err = mv88e6341_port_force_writable_cmode(chip, port);
+			if (err)
+				return err;
+		}
+
 		reg &= ~MV88E6XXX_PORT_STS_CMODE_MASK;
 		reg |= cmode;
 
@@ -484,21 +515,37 @@ int mv88e6390x_port_set_cmode(struct mv88e6xxx_chip *chip, int port,
 	return 0;
 }
 
+int mv88e6390x_port_set_cmode(struct mv88e6xxx_chip *chip, int port,
+			      phy_interface_t mode)
+{
+	if (port != 9 && port != 10)
+		return -EOPNOTSUPP;
+
+	return mv88e6xxx_port_set_cmode(chip, port, mode, true, false);
+}
+
 int mv88e6390_port_set_cmode(struct mv88e6xxx_chip *chip, int port,
 			     phy_interface_t mode)
 {
-	switch (mode) {
-	case PHY_INTERFACE_MODE_NA:
+	if (port != 9 && port != 10)
+		return -EOPNOTSUPP;
+
+	if (mode == PHY_INTERFACE_MODE_NA)
+		return 0;
+
+	return mv88e6xxx_port_set_cmode(chip, port, mode, false, false);
+}
+
+int mv88e6341_port_set_cmode(struct mv88e6xxx_chip *chip, int port,
+			     phy_interface_t mode)
+{
+	if (port != 5)
+		return -EOPNOTSUPP;
+
+	if (mode == PHY_INTERFACE_MODE_NA)
 		return 0;
-	case PHY_INTERFACE_MODE_XGMII:
-	case PHY_INTERFACE_MODE_XAUI:
-	case PHY_INTERFACE_MODE_RXAUI:
-		return -EINVAL;
-	default:
-		break;
-	}
 
-	return mv88e6390x_port_set_cmode(chip, port, mode);
+	return mv88e6xxx_port_set_cmode(chip, port, mode, false, true);
 }
 
 int mv88e6185_port_get_cmode(struct mv88e6xxx_chip *chip, int port, u8 *cmode)
diff --git a/drivers/net/dsa/mv88e6xxx/port.h b/drivers/net/dsa/mv88e6xxx/port.h
index cd48670f46ae..741f1d6db724 100644
--- a/drivers/net/dsa/mv88e6xxx/port.h
+++ b/drivers/net/dsa/mv88e6xxx/port.h
@@ -324,6 +324,8 @@ int mv88e6097_port_pause_limit(struct mv88e6xxx_chip *chip, int port, u8 in,
 			       u8 out);
 int mv88e6390_port_pause_limit(struct mv88e6xxx_chip *chip, int port, u8 in,
 			       u8 out);
+int mv88e6341_port_set_cmode(struct mv88e6xxx_chip *chip, int port,
+			     phy_interface_t mode);
 int mv88e6390_port_set_cmode(struct mv88e6xxx_chip *chip, int port,
 			     phy_interface_t mode);
 int mv88e6390x_port_set_cmode(struct mv88e6xxx_chip *chip, int port,
-- 
2.21.0