[PATCH net-next 3/4 v4] net: dsa: rtl8366rb: Support fast aging

[Linus Walleij <linus.walleij@linaro.org>]

This implements fast aging per-port using the special "security"
register, which will flush any learned L2 LUT entries on a port.

Suggested-by: Vladimir Oltean <olteanv@gmail.com>
Cc: Mauri Sandberg <sandberg@mailfence.com>
Cc: DENG Qingfang <dqfext@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
ChangeLog v3->v4:
- No changes, rebased on the other patches.
ChangeLog v2->v3:
- Underscore that this only affects learned L2 entries, not
  static ones.
ChangeLog v1->v2:
- New patch suggested by Vladimir.
---
 drivers/net/dsa/rtl8366rb.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/net/dsa/rtl8366rb.c b/drivers/net/dsa/rtl8366rb.c
index 52e750ea790e..748f22ab9130 100644
--- a/drivers/net/dsa/rtl8366rb.c
+++ b/drivers/net/dsa/rtl8366rb.c
@@ -1359,6 +1359,19 @@ rtl8366rb_port_bridge_flags(struct dsa_switch *ds, int port,
 	return 0;
 }
 
+static void
+rtl8366rb_port_fast_age(struct dsa_switch *ds, int port)
+{
+	struct realtek_smi *smi = ds->priv;
+
+	/* This will age out any learned L2 entries */
+	regmap_update_bits(smi->map, RTL8366RB_SECURITY_CTRL,
+			   BIT(port), BIT(port));
+	/* Restore the normal state of things */
+	regmap_update_bits(smi->map, RTL8366RB_SECURITY_CTRL,
+			   BIT(port), 0);
+}
+
 static int rtl8366rb_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
 {
 	struct realtek_smi *smi = ds->priv;
@@ -1771,6 +1784,7 @@ static const struct dsa_switch_ops rtl8366rb_switch_ops = {
 	.port_disable = rtl8366rb_port_disable,
 	.port_pre_bridge_flags = rtl8366rb_port_pre_bridge_flags,
 	.port_bridge_flags = rtl8366rb_port_bridge_flags,
+	.port_fast_age = rtl8366rb_port_fast_age,
 	.port_change_mtu = rtl8366rb_change_mtu,
 	.port_max_mtu = rtl8366rb_max_mtu,
 };
-- 
2.31.1