net: dsa: mv88e6xxx: don't set non-existing learn2all bit for 6220/6250

The 6220 and 6250 switches do not have a learn2all bit in global1, ATU
control register; bit 3 is reserverd.

On the switches that do have that bit, it is used to control whether
learning frames are sent out the ports that have the message_port bit
set. So rather than adding yet another chip method, use the existence
of the ->port_setup_message_port method as a proxy for determining
whether the learn2all bit exists (and should be set).

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Link: https://lore.kernel.org/r/20201210110645.27765-1-rasmus.villemoes@prevas.dk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index e7f68ac..eafe6be 100644 (file)
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -1347,9 +1347,16 @@ static int mv88e6xxx_atu_setup(struct mv88e6xxx_chip *chip)
        if (err)
                return err;
 
-       err = mv88e6xxx_g1_atu_set_learn2all(chip, true);
-       if (err)
-               return err;
+       /* The chips that have a "learn2all" bit in Global1, ATU
+        * Control are precisely those whose port registers have a
+        * Message Port bit in Port Control 1 and hence implement
+        * ->port_setup_message_port.
+        */
+       if (chip->info->ops->port_setup_message_port) {
+               err = mv88e6xxx_g1_atu_set_learn2all(chip, true);
+               if (err)
+                       return err;
+       }
 
        return mv88e6xxx_g1_atu_set_age_time(chip, 300000);
 }