[PATCH for 4.9 06/39] net: dsa: b53: Include IMP/CPU port in dumb forwarding mode

[Levin, Alexander (Sasha Levin)]

From: Florian Fainelli <f.faine...@gmail.com>

[ Upstream commit a424f0de61638cbb5047e0a888c54da9cf471f90 ]

Since Broadcom tags are not enabled in b53 (DSA_PROTO_TAG_NONE), we need
to make sure that the IMP/CPU port is included in the forwarding
decision.

Without this change, switching between non-management ports would work,
but not between management ports and non-management ports thus breaking
the default state in which DSA switch are brought up.

Fixes: 967dd82ffc52 ("net: dsa: b53: Add support for Broadcom RoboSwitch")
Reported-by: Eric Anholt <e...@anholt.net>
Signed-off-by: Florian Fainelli <f.faine...@gmail.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Sasha Levin <alexander.le...@verizon.com>
---
 drivers/net/dsa/b53/b53_common.c | 10 ++++++++++
 drivers/net/dsa/b53/b53_regs.h   |  4 ++++
 2 files changed, 14 insertions(+)

diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
index 3ec573c13dac..c26debc531ee 100644
--- a/drivers/net/dsa/b53/b53_common.c
+++ b/drivers/net/dsa/b53/b53_common.c
@@ -326,6 +326,7 @@ static void b53_get_vlan_entry(struct b53_device *dev, u16 
vid,
 
 static void b53_set_forwarding(struct b53_device *dev, int enable)
 {
+       struct dsa_switch *ds = dev->ds;
        u8 mgmt;
 
        b53_read8(dev, B53_CTRL_PAGE, B53_SWITCH_MODE, &mgmt);
@@ -336,6 +337,15 @@ static void b53_set_forwarding(struct b53_device *dev, int 
enable)
                mgmt &= ~SM_SW_FWD_EN;
 
        b53_write8(dev, B53_CTRL_PAGE, B53_SWITCH_MODE, mgmt);
+
+       /* Include IMP port in dumb forwarding mode when no tagging protocol is
+        * set
+        */
+       if (ds->ops->get_tag_protocol(ds) == DSA_TAG_PROTO_NONE) {
+               b53_read8(dev, B53_CTRL_PAGE, B53_SWITCH_CTRL, &mgmt);
+               mgmt |= B53_MII_DUMB_FWDG_EN;
+               b53_write8(dev, B53_CTRL_PAGE, B53_SWITCH_CTRL, mgmt);
+       }
 }
 
 static void b53_enable_vlan(struct b53_device *dev, bool enable)
diff --git a/drivers/net/dsa/b53/b53_regs.h b/drivers/net/dsa/b53/b53_regs.h
index dac0af4e2cd0..81044000ce75 100644
--- a/drivers/net/dsa/b53/b53_regs.h
+++ b/drivers/net/dsa/b53/b53_regs.h
@@ -104,6 +104,10 @@
 #define  B53_UC_FWD_EN                 BIT(6)
 #define  B53_MC_FWD_EN                 BIT(7)
 
+/* Switch control (8 bit) */
+#define B53_SWITCH_CTRL                        0x22
+#define  B53_MII_DUMB_FWDG_EN          BIT(6)
+
 /* (16 bit) */
 #define B53_UC_FLOOD_MASK              0x32
 #define B53_MC_FLOOD_MASK              0x34
-- 
2.11.0