net: dsa: mv88e6xxx: implement .port_set_policy for Amethyst

The 16-bit Port Policy CTL register from older chips is on 6393x changed
to Port Policy MGMT CTL, which can access more data, but indirectly and
via 8-bit registers.

The original 16-bit value is divided into first two 8-bit register in
the Port Policy MGMT CTL.

We can therefore use the previous code to compute the mask and shift,
and then
- if 0 <= shift < 8, we access register 0 in Port Policy MGMT CTL
- if 8 <= shift < 16, we access register 1 in Port Policy MGMT CTL

There are in fact other possible policy settings for Amethyst which
could be added here, but this can be done in the future.
Signed-off-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Pavana Sharma <pavana.sharma@digi.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx/chip.c

@@ -4627,6 +4627,7 @@ static const struct mv88e6xxx_ops mv88e6393x_ops = {
 	.port_set_speed_duplex = mv88e6393x_port_set_speed_duplex,
 	.port_max_speed_mode = mv88e6393x_port_max_speed_mode,
 	.port_tag_remap = mv88e6390_port_tag_remap,
+	.port_set_policy = mv88e6393x_port_set_policy,
 	.port_set_frame_mode = mv88e6351_port_set_frame_mode,
 	.port_set_ucast_flood = mv88e6352_port_set_ucast_flood,
 	.port_set_mcast_flood = mv88e6352_port_set_mcast_flood,

drivers/net/dsa/mv88e6xxx/port.c

@@ -1325,6 +1325,27 @@ int mv88e6xxx_port_disable_pri_override(struct mv88e6xxx_chip *chip, int port)
 
 /* Offset 0x0E: Policy & MGMT Control Register for FAMILY 6191X 6193X 6393X */
 
+static int mv88e6393x_port_policy_read(struct mv88e6xxx_chip *chip, int port,
+				       u16 pointer, u8 *data)
+{
+	u16 reg;
+	int err;
+
+	err = mv88e6xxx_port_write(chip, port, MV88E6393X_PORT_POLICY_MGMT_CTL,
+				   pointer);
+	if (err)
+		return err;
+
+	err = mv88e6xxx_port_read(chip, port, MV88E6393X_PORT_POLICY_MGMT_CTL,
+				  &reg);
+	if (err)
+		return err;
+
+	*data = reg;
+
+	return 0;
+}
+
 static int mv88e6393x_port_policy_write(struct mv88e6xxx_chip *chip, int port,
 					u16 pointer, u8 data)
 {
@@ -1526,46 +1547,43 @@ int mv88e6390_port_tag_remap(struct mv88e6xxx_chip *chip, int port)
 
 /* Offset 0x0E: Policy Control Register */
 
-int mv88e6352_port_set_policy(struct mv88e6xxx_chip *chip, int port,
-			      enum mv88e6xxx_policy_mapping mapping,
-			      enum mv88e6xxx_policy_action action)
+static int
+mv88e6xxx_port_policy_mapping_get_pos(enum mv88e6xxx_policy_mapping mapping,
+				      enum mv88e6xxx_policy_action action,
+				      u16 *mask, u16 *val, int *shift)
 {
-	u16 reg, mask, val;
-	int shift;
-	int err;
-
 	switch (mapping) {
 	case MV88E6XXX_POLICY_MAPPING_DA:
-		shift = __bf_shf(MV88E6XXX_PORT_POLICY_CTL_DA_MASK);
-		mask = MV88E6XXX_PORT_POLICY_CTL_DA_MASK;
+		*shift = __bf_shf(MV88E6XXX_PORT_POLICY_CTL_DA_MASK);
+		*mask = MV88E6XXX_PORT_POLICY_CTL_DA_MASK;
 		break;
 	case MV88E6XXX_POLICY_MAPPING_SA:
-		shift = __bf_shf(MV88E6XXX_PORT_POLICY_CTL_SA_MASK);
-		mask = MV88E6XXX_PORT_POLICY_CTL_SA_MASK;
+		*shift = __bf_shf(MV88E6XXX_PORT_POLICY_CTL_SA_MASK);
+		*mask = MV88E6XXX_PORT_POLICY_CTL_SA_MASK;
 		break;
 	case MV88E6XXX_POLICY_MAPPING_VTU:
-		shift = __bf_shf(MV88E6XXX_PORT_POLICY_CTL_VTU_MASK);
-		mask = MV88E6XXX_PORT_POLICY_CTL_VTU_MASK;
+		*shift = __bf_shf(MV88E6XXX_PORT_POLICY_CTL_VTU_MASK);
+		*mask = MV88E6XXX_PORT_POLICY_CTL_VTU_MASK;
 		break;
 	case MV88E6XXX_POLICY_MAPPING_ETYPE:
-		shift = __bf_shf(MV88E6XXX_PORT_POLICY_CTL_ETYPE_MASK);
-		mask = MV88E6XXX_PORT_POLICY_CTL_ETYPE_MASK;
+		*shift = __bf_shf(MV88E6XXX_PORT_POLICY_CTL_ETYPE_MASK);
+		*mask = MV88E6XXX_PORT_POLICY_CTL_ETYPE_MASK;
 		break;
 	case MV88E6XXX_POLICY_MAPPING_PPPOE:
-		shift = __bf_shf(MV88E6XXX_PORT_POLICY_CTL_PPPOE_MASK);
-		mask = MV88E6XXX_PORT_POLICY_CTL_PPPOE_MASK;
+		*shift = __bf_shf(MV88E6XXX_PORT_POLICY_CTL_PPPOE_MASK);
+		*mask = MV88E6XXX_PORT_POLICY_CTL_PPPOE_MASK;
 		break;
 	case MV88E6XXX_POLICY_MAPPING_VBAS:
-		shift = __bf_shf(MV88E6XXX_PORT_POLICY_CTL_VBAS_MASK);
-		mask = MV88E6XXX_PORT_POLICY_CTL_VBAS_MASK;
+		*shift = __bf_shf(MV88E6XXX_PORT_POLICY_CTL_VBAS_MASK);
+		*mask = MV88E6XXX_PORT_POLICY_CTL_VBAS_MASK;
 		break;
 	case MV88E6XXX_POLICY_MAPPING_OPT82:
-		shift = __bf_shf(MV88E6XXX_PORT_POLICY_CTL_OPT82_MASK);
-		mask = MV88E6XXX_PORT_POLICY_CTL_OPT82_MASK;
+		*shift = __bf_shf(MV88E6XXX_PORT_POLICY_CTL_OPT82_MASK);
+		*mask = MV88E6XXX_PORT_POLICY_CTL_OPT82_MASK;
 		break;
 	case MV88E6XXX_POLICY_MAPPING_UDP:
-		shift = __bf_shf(MV88E6XXX_PORT_POLICY_CTL_UDP_MASK);
-		mask = MV88E6XXX_PORT_POLICY_CTL_UDP_MASK;
+		*shift = __bf_shf(MV88E6XXX_PORT_POLICY_CTL_UDP_MASK);
+		*mask = MV88E6XXX_PORT_POLICY_CTL_UDP_MASK;
 		break;
 	default:
 		return -EOPNOTSUPP;
@@ -1573,21 +1591,37 @@ int mv88e6352_port_set_policy(struct mv88e6xxx_chip *chip, int port,
 
 	switch (action) {
 	case MV88E6XXX_POLICY_ACTION_NORMAL:
-		val = MV88E6XXX_PORT_POLICY_CTL_NORMAL;
+		*val = MV88E6XXX_PORT_POLICY_CTL_NORMAL;
 		break;
 	case MV88E6XXX_POLICY_ACTION_MIRROR:
-		val = MV88E6XXX_PORT_POLICY_CTL_MIRROR;
+		*val = MV88E6XXX_PORT_POLICY_CTL_MIRROR;
 		break;
 	case MV88E6XXX_POLICY_ACTION_TRAP:
-		val = MV88E6XXX_PORT_POLICY_CTL_TRAP;
+		*val = MV88E6XXX_PORT_POLICY_CTL_TRAP;
 		break;
 	case MV88E6XXX_POLICY_ACTION_DISCARD:
-		val = MV88E6XXX_PORT_POLICY_CTL_DISCARD;
+		*val = MV88E6XXX_PORT_POLICY_CTL_DISCARD;
 		break;
 	default:
 		return -EOPNOTSUPP;
 	}
 
+	return 0;
+}
+
+int mv88e6352_port_set_policy(struct mv88e6xxx_chip *chip, int port,
+			      enum mv88e6xxx_policy_mapping mapping,
+			      enum mv88e6xxx_policy_action action)
+{
+	u16 reg, mask, val;
+	int shift;
+	int err;
+
+	err = mv88e6xxx_port_policy_mapping_get_pos(mapping, action, &mask,
+						    &val, &shift);
+	if (err)
+		return err;
+
 	err = mv88e6xxx_port_read(chip, port, MV88E6XXX_PORT_POLICY_CTL, &reg);
 	if (err)
 		return err;
@@ -1597,3 +1631,37 @@ int mv88e6352_port_set_policy(struct mv88e6xxx_chip *chip, int port,
 
 	return mv88e6xxx_port_write(chip, port, MV88E6XXX_PORT_POLICY_CTL, reg);
 }
+
+int mv88e6393x_port_set_policy(struct mv88e6xxx_chip *chip, int port,
+			       enum mv88e6xxx_policy_mapping mapping,
+			       enum mv88e6xxx_policy_action action)
+{
+	u16 mask, val;
+	int shift;
+	int err;
+	u16 ptr;
+	u8 reg;
+
+	err = mv88e6xxx_port_policy_mapping_get_pos(mapping, action, &mask,
+						    &val, &shift);
+	if (err)
+		return err;
+
+	/* The 16-bit Port Policy CTL register from older chips is on 6393x
+	 * changed to Port Policy MGMT CTL, which can access more data, but
+	 * indirectly. The original 16-bit value is divided into two 8-bit
+	 * registers.
+	 */
+	ptr = shift / 8;
+	shift %= 8;
+	mask >>= ptr * 8;
+
+	err = mv88e6393x_port_policy_read(chip, port, ptr, &reg);
+	if (err)
+		return err;
+
+	reg &= ~mask;
+	reg |= (val << shift) & mask;
+
+	return mv88e6393x_port_policy_write(chip, port, ptr, reg);
+}

drivers/net/dsa/mv88e6xxx/port.h

@@ -386,6 +386,9 @@ int mv88e6352_port_set_mcast_flood(struct mv88e6xxx_chip *chip, int port,
 int mv88e6352_port_set_policy(struct mv88e6xxx_chip *chip, int port,
 			      enum mv88e6xxx_policy_mapping mapping,
 			      enum mv88e6xxx_policy_action action);
+int mv88e6393x_port_set_policy(struct mv88e6xxx_chip *chip, int port,
+			       enum mv88e6xxx_policy_mapping mapping,
+			       enum mv88e6xxx_policy_action action);
 int mv88e6351_port_set_ether_type(struct mv88e6xxx_chip *chip, int port,
 				  u16 etype);
 int mv88e6393x_set_egress_port(struct mv88e6xxx_chip *chip,