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From: Andrew Lunn <andrew@lunn.ch>
Date: Wed, 9 Jan 2019 00:24:03 +0100
Subject: net: dsa: mv88x6xxx: mv88e6390 errata
Git-commit: ea89098ef9a574bceca00d3b5df14aaf0b3f9ccf
Patch-mainline: v5.0-rc3
References: networking-stable-19_01_22

The 6390 copper ports have an errata which require poking magic values
into undocumented magic registers and then performing a software
reset.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/net/dsa/mv88e6xxx/chip.c      |  113 ++++++++++++++++++++++++++++++++++
 drivers/net/dsa/mv88e6xxx/mv88e6xxx.h |    5 +
 drivers/net/dsa/mv88e6xxx/port.h      |   10 +++
 3 files changed, 128 insertions(+)

--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -2331,6 +2331,107 @@ static int mv88e6xxx_g1_setup(struct mv8
 	return 0;
 }
 
+/* The mv88e6390 has some hidden registers used for debug and
+ * development. The errata also makes use of them.
+ */
+static int mv88e6390_hidden_write(struct mv88e6xxx_chip *chip, int port,
+				  int reg, u16 val)
+{
+	u16 ctrl;
+	int err;
+
+	err = mv88e6xxx_port_write(chip, PORT_RESERVED_1A_DATA_PORT,
+				   PORT_RESERVED_1A, val);
+	if (err)
+		return err;
+
+	ctrl = PORT_RESERVED_1A_BUSY | PORT_RESERVED_1A_WRITE |
+	       PORT_RESERVED_1A_BLOCK | port << PORT_RESERVED_1A_PORT_SHIFT |
+	       reg;
+
+	return mv88e6xxx_port_write(chip, PORT_RESERVED_1A_CTRL_PORT,
+				    PORT_RESERVED_1A, ctrl);
+}
+
+static int mv88e6390_hidden_wait(struct mv88e6xxx_chip *chip)
+{
+	return mv88e6xxx_wait(chip, PORT_RESERVED_1A_CTRL_PORT,
+			      PORT_RESERVED_1A, PORT_RESERVED_1A_BUSY);
+}
+
+
+static int mv88e6390_hidden_read(struct mv88e6xxx_chip *chip, int port,
+				  int reg, u16 *val)
+{
+	u16 ctrl;
+	int err;
+
+	ctrl = PORT_RESERVED_1A_BUSY | PORT_RESERVED_1A_READ |
+	       PORT_RESERVED_1A_BLOCK | port << PORT_RESERVED_1A_PORT_SHIFT |
+	       reg;
+
+	err = mv88e6xxx_port_write(chip, PORT_RESERVED_1A_CTRL_PORT,
+				   PORT_RESERVED_1A, ctrl);
+	if (err)
+		return err;
+
+	err = mv88e6390_hidden_wait(chip);
+	if (err)
+		return err;
+
+	return 	mv88e6xxx_port_read(chip, PORT_RESERVED_1A_DATA_PORT,
+				    PORT_RESERVED_1A, val);
+}
+
+/* Check if the errata has already been applied. */
+static bool mv88e6390_setup_errata_applied(struct mv88e6xxx_chip *chip)
+{
+	int port;
+	int err;
+	u16 val;
+
+	for (port = 0; port < mv88e6xxx_num_ports(chip); port++) {
+		err = mv88e6390_hidden_read(chip, port, 0, &val);
+		if (err) {
+			dev_err(chip->dev,
+				"Error reading hidden register: %d\n", err);
+			return false;
+		}
+		if (val != 0x01c0)
+			return false;
+	}
+
+	return true;
+}
+
+/* The 6390 copper ports have an errata which require poking magic
+ * values into undocumented hidden registers and then performing a
+ * software reset.
+ */
+static int mv88e6390_setup_errata(struct mv88e6xxx_chip *chip)
+{
+	int port;
+	int err;
+
+	if (mv88e6390_setup_errata_applied(chip))
+		return 0;
+
+	/* Set the ports into blocking mode */
+	for (port = 0; port < mv88e6xxx_num_ports(chip); port++) {
+		err = mv88e6xxx_port_set_state(chip, port, BR_STATE_DISABLED);
+		if (err)
+			return err;
+	}
+
+	for (port = 0; port < mv88e6xxx_num_ports(chip); port++) {
+		err = mv88e6390_hidden_write(chip, port, 0, 0x01c0);
+		if (err)
+			return err;
+	}
+
+	return mv88e6xxx_software_reset(chip);
+}
+
 static int mv88e6xxx_setup(struct dsa_switch *ds)
 {
 	struct mv88e6xxx_chip *chip = ds->priv;
@@ -2342,6 +2443,12 @@ static int mv88e6xxx_setup(struct dsa_sw
 
 	mutex_lock(&chip->reg_lock);
 
+	if (chip->info->ops->setup_errata) {
+		err = chip->info->ops->setup_errata(chip);
+		if (err)
+			goto unlock;
+	}
+
 	/* Setup Switch Port Registers */
 	for (i = 0; i < mv88e6xxx_num_ports(chip); i++) {
 		err = mv88e6xxx_setup_port(chip, i);
@@ -2975,6 +3082,7 @@ static const struct mv88e6xxx_ops mv88e6
 
 static const struct mv88e6xxx_ops mv88e6190_ops = {
 	/* MV88E6XXX_FAMILY_6390 */
+	.setup_errata = mv88e6390_setup_errata,
 	.get_eeprom = mv88e6xxx_g2_get_eeprom8,
 	.set_eeprom = mv88e6xxx_g2_set_eeprom8,
 	.set_switch_mac = mv88e6xxx_g2_set_switch_mac,
@@ -3007,6 +3115,7 @@ static const struct mv88e6xxx_ops mv88e6
 
 static const struct mv88e6xxx_ops mv88e6190x_ops = {
 	/* MV88E6XXX_FAMILY_6390 */
+	.setup_errata = mv88e6390_setup_errata,
 	.get_eeprom = mv88e6xxx_g2_get_eeprom8,
 	.set_eeprom = mv88e6xxx_g2_set_eeprom8,
 	.set_switch_mac = mv88e6xxx_g2_set_switch_mac,
@@ -3039,6 +3148,7 @@ static const struct mv88e6xxx_ops mv88e6
 
 static const struct mv88e6xxx_ops mv88e6191_ops = {
 	/* MV88E6XXX_FAMILY_6390 */
+	.setup_errata = mv88e6390_setup_errata,
 	.get_eeprom = mv88e6xxx_g2_get_eeprom8,
 	.set_eeprom = mv88e6xxx_g2_set_eeprom8,
 	.set_switch_mac = mv88e6xxx_g2_set_switch_mac,
@@ -3104,6 +3214,7 @@ static const struct mv88e6xxx_ops mv88e6
 
 static const struct mv88e6xxx_ops mv88e6290_ops = {
 	/* MV88E6XXX_FAMILY_6390 */
+	.setup_errata = mv88e6390_setup_errata,
 	.get_eeprom = mv88e6xxx_g2_get_eeprom8,
 	.set_eeprom = mv88e6xxx_g2_set_eeprom8,
 	.set_switch_mac = mv88e6xxx_g2_set_switch_mac,
@@ -3326,6 +3437,7 @@ static const struct mv88e6xxx_ops mv88e6
 
 static const struct mv88e6xxx_ops mv88e6390_ops = {
 	/* MV88E6XXX_FAMILY_6390 */
+	.setup_errata = mv88e6390_setup_errata,
 	.get_eeprom = mv88e6xxx_g2_get_eeprom8,
 	.set_eeprom = mv88e6xxx_g2_set_eeprom8,
 	.set_switch_mac = mv88e6xxx_g2_set_switch_mac,
@@ -3361,6 +3473,7 @@ static const struct mv88e6xxx_ops mv88e6
 
 static const struct mv88e6xxx_ops mv88e6390x_ops = {
 	/* MV88E6XXX_FAMILY_6390 */
+	.setup_errata = mv88e6390_setup_errata,
 	.get_eeprom = mv88e6xxx_g2_get_eeprom8,
 	.set_eeprom = mv88e6xxx_g2_set_eeprom8,
 	.set_switch_mac = mv88e6xxx_g2_set_switch_mac,
--- a/drivers/net/dsa/mv88e6xxx/mv88e6xxx.h
+++ b/drivers/net/dsa/mv88e6xxx/mv88e6xxx.h
@@ -779,6 +779,11 @@ struct mv88e6xxx_mdio_bus {
 };
 
 struct mv88e6xxx_ops {
+	/* Switch Setup Errata, called early in the switch setup to
+	 * allow any errata actions to be performed
+	 */
+	int (*setup_errata)(struct mv88e6xxx_chip *chip);
+
 	int (*get_eeprom)(struct mv88e6xxx_chip *chip,
 			  struct ethtool_eeprom *eeprom, u8 *data);
 	int (*set_eeprom)(struct mv88e6xxx_chip *chip,
--- a/drivers/net/dsa/mv88e6xxx/port.h
+++ b/drivers/net/dsa/mv88e6xxx/port.h
@@ -17,6 +17,16 @@
 
 #include "mv88e6xxx.h"
 
+/* Offset 0x1a: Magic undocumented errata register */
+#define PORT_RESERVED_1A			0x1a
+#define PORT_RESERVED_1A_BUSY			BIT(15)
+#define PORT_RESERVED_1A_WRITE			BIT(14)
+#define PORT_RESERVED_1A_READ			0
+#define PORT_RESERVED_1A_PORT_SHIFT		5
+#define PORT_RESERVED_1A_BLOCK			(0xf << 10)
+#define PORT_RESERVED_1A_CTRL_PORT		4
+#define PORT_RESERVED_1A_DATA_PORT		5
+
 int mv88e6xxx_port_read(struct mv88e6xxx_chip *chip, int port, int reg,
 			u16 *val);
 int mv88e6xxx_port_write(struct mv88e6xxx_chip *chip, int port, int reg,