net: dsa: mv88e6xxx: add a soft reset operation

Marvell chips have different way to issue a software reset.

Old chips (such as 88E6060) have a reset bit in an ATU control register.

Newer chips moved this bit in a Global control register. Chips with
controllable PPU should reset the PPU when resetting the switch.

Add a new reset operation to implement these differences and introduce a
mv88e6xxx_software_reset() helper to wrap it conveniently.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/dsa/mv88e6xxx/global1.h b/drivers/net/dsa/mv88e6xxx/global1.h
index cb61378..9fca215 100644
--- a/drivers/net/dsa/mv88e6xxx/global1.h
+++ b/drivers/net/dsa/mv88e6xxx/global1.h
@@ -19,6 +19,10 @@
 int mv88e6xxx_g1_read(struct mv88e6xxx_chip *chip, int reg, u16 *val);
 int mv88e6xxx_g1_write(struct mv88e6xxx_chip *chip, int reg, u16 val);
 int mv88e6xxx_g1_wait(struct mv88e6xxx_chip *chip, int reg, u16 mask);
+
+int mv88e6185_g1_reset(struct mv88e6xxx_chip *chip);
+int mv88e6352_g1_reset(struct mv88e6xxx_chip *chip);
+
 int mv88e6xxx_g1_stats_wait(struct mv88e6xxx_chip *chip);
 int mv88e6xxx_g1_stats_snapshot(struct mv88e6xxx_chip *chip, int port);
 int mv88e6320_g1_stats_snapshot(struct mv88e6xxx_chip *chip, int port);