BCM5325 doesn't implement SWITCH_CTRL register so we should avoid reading
or writing it.

Fixes: a424f0de6163 ("net: dsa: b53: Include IMP/CPU port in dumb forwarding mode")
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---
 drivers/net/dsa/b53/b53_common.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

 v4: no changes

 v3: no changes

 v2: no changes

diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
index e4e71d193b39..24a9a0372122 100644
--- a/drivers/net/dsa/b53/b53_common.c
+++ b/drivers/net/dsa/b53/b53_common.c
@@ -361,11 +361,12 @@ static void b53_set_forwarding(struct b53_device *dev, int enable)
 
 	b53_write8(dev, B53_CTRL_PAGE, B53_SWITCH_MODE, mgmt);
 
-	/* Include IMP port in dumb forwarding mode
-	 */
-	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);
+	if (!is5325(dev)) {
+		/* Include IMP port in dumb forwarding mode */
+		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);
+	}
 
 	/* Look at B53_UC_FWD_EN and B53_MC_FWD_EN to decide whether
 	 * frames should be flooded or not.
-- 
2.39.5