| From foo@baz Wed Sep 30 05:25:07 CEST 2015 |
| From: Russell King <rmk+kernel@arm.linux.org.uk> |
| Date: Mon, 21 Sep 2015 21:42:59 +0100 |
| Subject: net: dsa: actually force the speed on the CPU port |
| |
| From: Russell King <rmk+kernel@arm.linux.org.uk> |
| |
| [ Upstream commit 53adc9e83028d9e35b6408231ebaf62a94a16e4d ] |
| |
| Commit 54d792f257c6 ("net: dsa: Centralise global and port setup |
| code into mv88e6xxx.") merged in the 4.2 merge window broke the link |
| speed forcing for the CPU port of Marvell DSA switches. The original |
| code was: |
| |
| /* MAC Forcing register: don't force link, speed, duplex |
| * or flow control state to any particular values on physical |
| * ports, but force the CPU port and all DSA ports to 1000 Mb/s |
| * full duplex. |
| */ |
| if (dsa_is_cpu_port(ds, p) || ds->dsa_port_mask & (1 << p)) |
| REG_WRITE(addr, 0x01, 0x003e); |
| else |
| REG_WRITE(addr, 0x01, 0x0003); |
| |
| but the new code does a read-modify-write: |
| |
| reg = _mv88e6xxx_reg_read(ds, REG_PORT(port), PORT_PCS_CTRL); |
| if (dsa_is_cpu_port(ds, port) || |
| ds->dsa_port_mask & (1 << port)) { |
| reg |= PORT_PCS_CTRL_FORCE_LINK | |
| PORT_PCS_CTRL_LINK_UP | |
| PORT_PCS_CTRL_DUPLEX_FULL | |
| PORT_PCS_CTRL_FORCE_DUPLEX; |
| if (mv88e6xxx_6065_family(ds)) |
| reg |= PORT_PCS_CTRL_100; |
| else |
| reg |= PORT_PCS_CTRL_1000; |
| |
| The link speed in the PCS control register is a two bit field. Forcing |
| the link speed in this way doesn't ensure that the bit field is set to |
| the correct value - on the hardware I have here, the speed bitfield |
| remains set to 0x03, resulting in the speed not being forced to gigabit. |
| |
| We must clear both bits before forcing the link speed. |
| |
| Fixes: 54d792f257c6 ("net: dsa: Centralise global and port setup code into mv88e6xxx.") |
| Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> |
| Acked-by: Andrew Lunn <andrew@lunn.ch> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/net/dsa/mv88e6xxx.c | 1 + |
| 1 file changed, 1 insertion(+) |
| |
| --- a/drivers/net/dsa/mv88e6xxx.c |
| +++ b/drivers/net/dsa/mv88e6xxx.c |
| @@ -1387,6 +1387,7 @@ static int mv88e6xxx_setup_port(struct d |
| reg = _mv88e6xxx_reg_read(ds, REG_PORT(port), PORT_PCS_CTRL); |
| if (dsa_is_cpu_port(ds, port) || |
| ds->dsa_port_mask & (1 << port)) { |
| + reg &= ~PORT_PCS_CTRL_UNFORCED; |
| reg |= PORT_PCS_CTRL_FORCE_LINK | |
| PORT_PCS_CTRL_LINK_UP | |
| PORT_PCS_CTRL_DUPLEX_FULL | |
