[PATCH v5 net-next 08/12] net: dsa: sja1105: Add support for configuring address ageing time

[Vladimir Oltean <olteanv@gmail.com>]

If STP is active, this setting is applied on bridged ports each time an
Ethernet link is established (topology changes).

Since the setting is global to the switch and a reset is required to
change it, resets are prevented if the new callback does not change the
value that the hardware already is programmed for.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
---
Changes in v5:
Changed "aging" to "ageing" in commit message to be consistent with the
code.

Changes in v4:
Patch is new.

 drivers/net/dsa/sja1105/sja1105.h      |  4 ++++
 drivers/net/dsa/sja1105/sja1105_main.c | 29 ++++++++++++++++++++++++--
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/drivers/net/dsa/sja1105/sja1105.h b/drivers/net/dsa/sja1105/sja1105.h
index 38506bde83c6..0489d9adf957 100644
--- a/drivers/net/dsa/sja1105/sja1105.h
+++ b/drivers/net/dsa/sja1105/sja1105.h
@@ -12,6 +12,10 @@
 #define SJA1105_NUM_PORTS		5
 #define SJA1105_NUM_TC			8
 #define SJA1105ET_FDB_BIN_SIZE		4
+/* The hardware value is in multiples of 10 ms.
+ * The passed parameter is in multiples of 1 ms.
+ */
+#define SJA1105_AGEING_TIME_MS(ms)	((ms) / 10)
 
 /* Keeps the different addresses between E/T and P/Q/R/S */
 struct sja1105_regs {
diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c
index 28b11c7a81e7..f5205ce85dbe 100644
--- a/drivers/net/dsa/sja1105/sja1105_main.c
+++ b/drivers/net/dsa/sja1105/sja1105_main.c
@@ -193,8 +193,8 @@ static int sja1105_init_l2_lookup_params(struct sja1105_private *priv)
 {
 	struct sja1105_table *table;
 	struct sja1105_l2_lookup_params_entry default_l2_lookup_params = {
-		/* TODO Learned FDB entries are never forgotten */
-		.maxage = 0,
+		/* Learned FDB entries are forgotten after 300 seconds */
+		.maxage = SJA1105_AGEING_TIME_MS(300000),
 		/* All entries within a FDB bin are available for learning */
 		.dyn_tbsz = SJA1105ET_FDB_BIN_SIZE,
 		/* 2^8 + 2^5 + 2^3 + 2^2 + 2^1 + 1 in Koopman notation */
@@ -1249,10 +1249,35 @@ static int sja1105_setup(struct dsa_switch *ds)
 	return 0;
 }
 
+/* The MAXAGE setting belongs to the L2 Forwarding Parameters table,
+ * which cannot be reconfigured at runtime. So a switch reset is required.
+ */
+static int sja1105_set_ageing_time(struct dsa_switch *ds,
+				   unsigned int ageing_time)
+{
+	struct sja1105_l2_lookup_params_entry *l2_lookup_params;
+	struct sja1105_private *priv = ds->priv;
+	struct sja1105_table *table;
+	unsigned int maxage;
+
+	table = &priv->static_config.tables[BLK_IDX_L2_LOOKUP_PARAMS];
+	l2_lookup_params = table->entries;
+
+	maxage = SJA1105_AGEING_TIME_MS(ageing_time);
+
+	if (l2_lookup_params->maxage == maxage)
+		return 0;
+
+	l2_lookup_params->maxage = maxage;
+
+	return sja1105_static_config_reload(priv);
+}
+
 static const struct dsa_switch_ops sja1105_switch_ops = {
 	.get_tag_protocol	= sja1105_get_tag_protocol,
 	.setup			= sja1105_setup,
 	.adjust_link		= sja1105_adjust_link,
+	.set_ageing_time	= sja1105_set_ageing_time,
 	.get_strings		= sja1105_get_strings,
 	.get_ethtool_stats	= sja1105_get_ethtool_stats,
 	.get_sset_count		= sja1105_get_sset_count,
-- 
2.17.1