net: dsa: mv88e6xxx: add port's MAC speed setter

While the two bits for link, duplex or RGMII delays are used the same
way on chips supporting the said feature, the two bits for speed have
different meaning for most of the chips out there.

Speed value is stored in bits 1:0, 0x3 means unforce (normal detection).

Some chips reuse values for alternative speeds when bit 12 is set.

Newer chips with speed > 1Gbps reuse value 0x3 thus need a new bit 13.

Here are the values to write in register 0x1 to (un)force speed:

    | Speed   | 88E6065 | 88E6185 | 88E6352 | 88E6390 | 88E6390X |
    | ------- | ------- | ------- | ------- | ------- | -------- |
    | 10      | 0x0000  | 0x0000  | 0x0000  | 0x2000  | 0x2000   |
    | 100     | 0x0001  | 0x0001  | 0x0001  | 0x2001  | 0x2001   |
    | 200     | 0x0002  | NA      | 0x1001  | 0x3001  | 0x3001   |
    | 1000    | NA      | 0x0002  | 0x0002  | 0x2002  | 0x2002   |
    | 2500    | NA      | NA      | NA      | 0x3003  | 0x3003   |
    | 10000   | NA      | NA      | NA      | NA      | 0x2003   |
    | unforce | 0x0003  | 0x0003  | 0x0003  | 0x0000  | 0x0000   |

This patch implements a generic mv88e6xxx_port_set_speed() function used
by chip-specific wrappers to filter supported ports and speeds.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 138 insertions, 0 deletions

diff --git a/drivers/net/dsa/mv88e6xxx/port.c b/drivers/net/dsa/mv88e6xxx/port.c
index 838068d2b581..18eeed083cbd 100644
--- a/drivers/net/dsa/mv88e6xxx/port.c
+++ b/drivers/net/dsa/mv88e6xxx/port.c
@@ -33,6 +33,10 @@ int mv88e6xxx_port_write(struct mv88e6xxx_chip *chip, int port, int reg,
 /* Offset 0x01: MAC (or PCS or Physical) Control Register
  *
  * Link, Duplex and Flow Control have one force bit, one value bit.
+ *
+ * For port's MAC speed, ForceSpd (or SpdValue) bits 1:0 program the value.
+ * Alternative values require the 200BASE (or AltSpeed) bit 12 set.
+ * Newer chips need a ForcedSpd bit 13 set to consider the value.
  */
 
 static int mv88e6xxx_port_set_rgmii_delay(struct mv88e6xxx_chip *chip, int port,
@@ -165,6 +169,140 @@ int mv88e6xxx_port_set_duplex(struct mv88e6xxx_chip *chip, int port, int dup)
 	return 0;
 }
 
+static int mv88e6xxx_port_set_speed(struct mv88e6xxx_chip *chip, int port,
+				    int speed, bool alt_bit, bool force_bit)
+{
+	u16 reg, ctrl;
+	int err;
+
+	switch (speed) {
+	case 10:
+		ctrl = PORT_PCS_CTRL_SPEED_10;
+		break;
+	case 100:
+		ctrl = PORT_PCS_CTRL_SPEED_100;
+		break;
+	case 200:
+		if (alt_bit)
+			ctrl = PORT_PCS_CTRL_SPEED_100 | PORT_PCS_CTRL_ALTSPEED;
+		else
+			ctrl = PORT_PCS_CTRL_SPEED_200;
+		break;
+	case 1000:
+		ctrl = PORT_PCS_CTRL_SPEED_1000;
+		break;
+	case 2500:
+		ctrl = PORT_PCS_CTRL_SPEED_1000 | PORT_PCS_CTRL_ALTSPEED;
+		break;
+	case 10000:
+		/* all bits set, fall through... */
+	case SPEED_UNFORCED:
+		ctrl = PORT_PCS_CTRL_SPEED_UNFORCED;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	err = mv88e6xxx_port_read(chip, port, PORT_PCS_CTRL, &reg);
+	if (err)
+		return err;
+
+	reg &= ~PORT_PCS_CTRL_SPEED_MASK;
+	if (alt_bit)
+		reg &= ~PORT_PCS_CTRL_ALTSPEED;
+	if (force_bit) {
+		reg &= ~PORT_PCS_CTRL_FORCE_SPEED;
+		if (speed)
+			ctrl |= PORT_PCS_CTRL_FORCE_SPEED;
+	}
+	reg |= ctrl;
+
+	err = mv88e6xxx_port_write(chip, port, PORT_PCS_CTRL, reg);
+	if (err)
+		return err;
+
+	if (speed)
+		netdev_dbg(chip->ds->ports[port].netdev,
+			   "Speed set to %d Mbps\n", speed);
+	else
+		netdev_dbg(chip->ds->ports[port].netdev, "Speed unforced\n");
+
+	return 0;
+}
+
+/* Support 10, 100, 200 Mbps (e.g. 88E6065 family) */
+int mv88e6065_port_set_speed(struct mv88e6xxx_chip *chip, int port, int speed)
+{
+	if (speed == SPEED_MAX)
+		speed = 200;
+
+	if (speed > 200)
+		return -EOPNOTSUPP;
+
+	/* Setting 200 Mbps on port 0 to 3 selects 100 Mbps */
+	return mv88e6xxx_port_set_speed(chip, port, speed, false, false);
+}
+
+/* Support 10, 100, 1000 Mbps (e.g. 88E6185 family) */
+int mv88e6185_port_set_speed(struct mv88e6xxx_chip *chip, int port, int speed)
+{
+	if (speed == SPEED_MAX)
+		speed = 1000;
+
+	if (speed == 200 || speed > 1000)
+		return -EOPNOTSUPP;
+
+	return mv88e6xxx_port_set_speed(chip, port, speed, false, false);
+}
+
+/* Support 10, 100, 200, 1000 Mbps (e.g. 88E6352 family) */
+int mv88e6352_port_set_speed(struct mv88e6xxx_chip *chip, int port, int speed)
+{
+	if (speed == SPEED_MAX)
+		speed = 1000;
+
+	if (speed > 1000)
+		return -EOPNOTSUPP;
+
+	if (speed == 200 && port < 5)
+		return -EOPNOTSUPP;
+
+	return mv88e6xxx_port_set_speed(chip, port, speed, true, false);
+}
+
+/* Support 10, 100, 200, 1000, 2500 Mbps (e.g. 88E6390) */
+int mv88e6390_port_set_speed(struct mv88e6xxx_chip *chip, int port, int speed)
+{
+	if (speed == SPEED_MAX)
+		speed = port < 9 ? 1000 : 2500;
+
+	if (speed > 2500)
+		return -EOPNOTSUPP;
+
+	if (speed == 200 && port != 0)
+		return -EOPNOTSUPP;
+
+	if (speed == 2500 && port < 9)
+		return -EOPNOTSUPP;
+
+	return mv88e6xxx_port_set_speed(chip, port, speed, true, true);
+}
+
+/* Support 10, 100, 200, 1000, 2500, 10000 Mbps (e.g. 88E6190X) */
+int mv88e6390x_port_set_speed(struct mv88e6xxx_chip *chip, int port, int speed)
+{
+	if (speed == SPEED_MAX)
+		speed = port < 9 ? 1000 : 10000;
+
+	if (speed == 200 && port != 0)
+		return -EOPNOTSUPP;
+
+	if (speed >= 2500 && port < 9)
+		return -EOPNOTSUPP;
+
+	return mv88e6xxx_port_set_speed(chip, port, speed, true, true);
+}
+
 /* Offset 0x04: Port Control Register */
 
 static const char * const mv88e6xxx_port_state_names[] = {