From: Vladimir Oltean <vladimir.oltean@xxxxxxx>
[ Upstream commit 601e984f23abcaa7cf3eb078c13de4db3cf6a4f0 ]
Tail dropping is enabled for a port when:
1. A source port consumes more packet buffers than the watermark encoded
in SYS:PORT:ATOP_CFG.ATOP.
AND
2. Total memory use exceeds the consumption watermark encoded in
SYS:PAUSE_CFG:ATOP_TOT_CFG.
The unit of these watermarks is a 60 byte memory cell. That unit is
programmed properly into ATOP_TOT_CFG, but not into ATOP. Actually when
written into ATOP, it would get truncated and wrap around.
Fixes: a556c76adc05 ("net: mscc: Add initial Ocelot switch support")
Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/ethernet/mscc/ocelot.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index 1438839e3f6ea..61bbb7a090042 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -2001,7 +2001,7 @@ 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;
@@ -2022,12 +2022,12 @@ void ocelot_port_set_maxlen(struct ocelot *ocelot, int port, size_t sdu)
ocelot_rmw_rix(ocelot, SYS_PAUSE_CFG_PAUSE_STOP(pause_stop),
SYS_PAUSE_CFG_PAUSE_STOP_M, SYS_PAUSE_CFG, port);
- /* 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);
--
2.25.1
