Merge branch 'Fix-tail-dropping-watermarks-for-Ocelot-switches'

Vladimir Oltean says:

====================
Fix tail dropping watermarks for Ocelot switches

This series adds a missing division by 60, and a warning to prevent that
in the future.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Author: davem330

drivers/net/dsa/ocelot/felix_vsc9959.c

@@ -1171,6 +1171,8 @@ static int vsc9959_prevalidate_phy_mode(struct ocelot *ocelot, int port,
  */
 static u16 vsc9959_wm_enc(u16 value)
 {
+	WARN_ON(value >= 16 * BIT(8));
+
 	if (value >= BIT(8))
 		return BIT(8) | (value / 16);
 

drivers/net/dsa/ocelot/seville_vsc9953.c

@@ -911,6 +911,8 @@ static int vsc9953_prevalidate_phy_mode(struct ocelot *ocelot, int port,
  */
 static u16 vsc9953_wm_enc(u16 value)
 {
+	WARN_ON(value >= 16 * BIT(9));
+
 	if (value >= BIT(9))
 		return BIT(9) | (value / 16);
 

drivers/net/ethernet/mscc/ocelot.c

@@ -1253,7 +1253,7 @@ void ocelot_port_set_maxlen(struct ocelot *ocelot, int port, size_t sdu)
 	struct ocelot_port *ocelot_port = ocelot->ports[port];
 	int maxlen = sdu + ETH_HLEN + ETH_FCS_LEN;
 	int pause_start, pause_stop;
-	int atop_wm;
+	int atop, atop_tot;
 
 	if (port == ocelot->npi) {
 		maxlen += OCELOT_TAG_LEN;
@@ -1274,12 +1274,12 @@ void ocelot_port_set_maxlen(struct ocelot *ocelot, int port, size_t sdu)
 	ocelot_fields_write(ocelot, port, SYS_PAUSE_CFG_PAUSE_STOP,
 			    pause_stop);
 
-	/* Tail dropping watermark */
-	atop_wm = (ocelot->shared_queue_sz - 9 * maxlen) /
+	/* Tail dropping watermarks */
+	atop_tot = (ocelot->shared_queue_sz - 9 * maxlen) /
 		   OCELOT_BUFFER_CELL_SZ;
-	ocelot_write_rix(ocelot, ocelot->ops->wm_enc(9 * maxlen),
-			 SYS_ATOP, port);
-	ocelot_write(ocelot, ocelot->ops->wm_enc(atop_wm), SYS_ATOP_TOT_CFG);
+	atop = (9 * maxlen) / OCELOT_BUFFER_CELL_SZ;
+	ocelot_write_rix(ocelot, ocelot->ops->wm_enc(atop), SYS_ATOP, port);
+	ocelot_write(ocelot, ocelot->ops->wm_enc(atop_tot), SYS_ATOP_TOT_CFG);
 }
 EXPORT_SYMBOL(ocelot_port_set_maxlen);
 

drivers/net/ethernet/mscc/ocelot_vsc7514.c

@@ -745,6 +745,8 @@ static int ocelot_reset(struct ocelot *ocelot)
  */
 static u16 ocelot_wm_enc(u16 value)
 {
+	WARN_ON(value >= 16 * BIT(8));
+
 	if (value >= BIT(8))
 		return BIT(8) | (value / 16);