Subject: [PATCH 04/10] net: dsa: mv88x6xxx: mv88e6390 errata

From: Andrew Lunn <[email-masked]>
Date: Wed, 9 Jan 2019 00:24:03 +0100

[ Upstream commit ea89098ef9a574bceca00d3b5df14aaf0b3f9ccf ]

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 <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 113 +++++++++++++++++++++++++++++++
 drivers/net/dsa/mv88e6xxx/chip.h |   5 ++
 drivers/net/dsa/mv88e6xxx/port.h |  10 +++
 3 files changed, 128 insertions(+)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 8da3d39e3218..258918d8a416 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -2391,6 +2391,107 @@ static int mv88e6xxx_stats_setup(struct mv88e6xxx_chip *chip)
 	return mv88e6xxx_g1_stats_clear(chip);
 }
 
+/* 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;
@@ -2403,6 +2504,12 @@ static int mv88e6xxx_setup(struct dsa_switch *ds)
 
 	mutex_lock(&chip->reg_lock);
 
+	if (chip->info->ops->setup_errata) {
+		err = chip->info->ops->setup_errata(chip);
+		if (err)
+			goto unlock;
+	}
+
 	/* Cache the cmode of each port. */
 	for (i = 0; i < mv88e6xxx_num_ports(chip); i++) {
 		if (chip->info->ops->port_get_cmode) {
@@ -3201,6 +3308,7 @@ static const struct mv88e6xxx_ops mv88e6185_ops = {
 
 static const struct mv88e6xxx_ops mv88e6190_ops = {
 	/* MV88E6XXX_FAMILY_6390 */
+	.setup_errata = mv88e6390_setup_errata,
 	.irl_init_all = mv88e6390_g2_irl_init_all,
 	.get_eeprom = mv88e6xxx_g2_get_eeprom8,
 	.set_eeprom = mv88e6xxx_g2_set_eeprom8,
@@ -3243,6 +3351,7 @@ static const struct mv88e6xxx_ops mv88e6190_ops = {
 
 static const struct mv88e6xxx_ops mv88e6190x_ops = {
 	/* MV88E6XXX_FAMILY_6390 */
+	.setup_errata = mv88e6390_setup_errata,
 	.irl_init_all = mv88e6390_g2_irl_init_all,
 	.get_eeprom = mv88e6xxx_g2_get_eeprom8,
 	.set_eeprom = mv88e6xxx_g2_set_eeprom8,
@@ -3285,6 +3394,7 @@ static const struct mv88e6xxx_ops mv88e6190x_ops = {
 
 static const struct mv88e6xxx_ops mv88e6191_ops = {
 	/* MV88E6XXX_FAMILY_6390 */
+	.setup_errata = mv88e6390_setup_errata,
 	.irl_init_all = mv88e6390_g2_irl_init_all,
 	.get_eeprom = mv88e6xxx_g2_get_eeprom8,
 	.set_eeprom = mv88e6xxx_g2_set_eeprom8,
@@ -3374,6 +3484,7 @@ static const struct mv88e6xxx_ops mv88e6240_ops = {
 
 static const struct mv88e6xxx_ops mv88e6290_ops = {
 	/* MV88E6XXX_FAMILY_6390 */
+	.setup_errata = mv88e6390_setup_errata,
 	.irl_init_all = mv88e6390_g2_irl_init_all,
 	.get_eeprom = mv88e6xxx_g2_get_eeprom8,
 	.set_eeprom = mv88e6xxx_g2_set_eeprom8,
@@ -3675,6 +3786,7 @@ static const struct mv88e6xxx_ops mv88e6352_ops = {
 
 static const struct mv88e6xxx_ops mv88e6390_ops = {
 	/* MV88E6XXX_FAMILY_6390 */
+	.setup_errata = mv88e6390_setup_errata,
 	.irl_init_all = mv88e6390_g2_irl_init_all,
 	.get_eeprom = mv88e6xxx_g2_get_eeprom8,
 	.set_eeprom = mv88e6xxx_g2_set_eeprom8,
@@ -3722,6 +3834,7 @@ static const struct mv88e6xxx_ops mv88e6390_ops = {
 
 static const struct mv88e6xxx_ops mv88e6390x_ops = {
 	/* MV88E6XXX_FAMILY_6390 */
+	.setup_errata = mv88e6390_setup_errata,
 	.irl_init_all = mv88e6390_g2_irl_init_all,
 	.get_eeprom = mv88e6xxx_g2_get_eeprom8,
 	.set_eeprom = mv88e6xxx_g2_set_eeprom8,
diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h
index f9ecb7872d32..546651d8c3e1 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.h
+++ b/drivers/net/dsa/mv88e6xxx/chip.h
@@ -300,6 +300,11 @@ 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 (*ieee_pri_map)(struct mv88e6xxx_chip *chip);
 	int (*ip_pri_map)(struct mv88e6xxx_chip *chip);
 
diff --git a/drivers/net/dsa/mv88e6xxx/port.h b/drivers/net/dsa/mv88e6xxx/port.h
index f32f56af8e35..b31910023bb6 100644
--- a/drivers/net/dsa/mv88e6xxx/port.h
+++ b/drivers/net/dsa/mv88e6xxx/port.h
@@ -251,6 +251,16 @@
 /* Offset 0x19: Port IEEE Priority Remapping Registers (4-7) */
 #define MV88E6095_PORT_IEEE_PRIO_REMAP_4567	0x19
 
+/* 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,
-- 
2.20.1