net: mscc: ocelot: warn when encoding an out-of-bounds watermark value
There is an upper bound to the value that a watermark may hold. That
upper bound is not immediately obvious during configuration, and it
might be possible to have accidental truncation.
Actually this has happened already, add a warning to prevent it from
happening again.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/dsa/ocelot/seville_vsc9953.c b/drivers/net/dsa/ocelot/seville_vsc9953.c
index 110070a..9e9fd19 100644
--- a/drivers/net/dsa/ocelot/seville_vsc9953.c
+++ b/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);