net: mscc: ocelot: divide watermark value by 60 when writing to SYS_ATOP (601e984f) · Commits · 戴 / test

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: ("net: mscc: Add initial Ocelot switch support") Signed-off-by:

Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mscc/ocelot.c

+6 −6

Original line number	Diff line number	Diff line
		@@ -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);

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