[PATCH v4 net-next 05/16] net: mscc: ocelot: don't use NPI tag prefix for the CPU port module

[Vladimir Oltean <olteanv@gmail.com>]

From: Vladimir Oltean <vladimir.oltean@nxp.com>

Context: Ocelot switches put the injection/extraction frame header in
front of the Ethernet header. When used in NPI mode, a DSA master would
see junk instead of the destination MAC address, and it would most
likely drop the packets. So the Ocelot frame header can have an optional
prefix, which is just "ff:ff:ff:ff:ff:fe > ff:ff:ff:ff:ff:ff" padding
put before the actual tag (still before the real Ethernet header) such
that the DSA master thinks it's looking at a broadcast frame with a
strange EtherType.

Unfortunately, a lesson learned in commit 69df578c5f4b ("net: mscc:
ocelot: eliminate confusion between CPU and NPI port") seems to have
been forgotten in the meanwhile.

The CPU port module and the NPI port have independent settings for the
length of the tag prefix. However, the driver is using the same variable
to program both of them.

There is no reason really to use any tag prefix with the CPU port
module, since that is not connected to any Ethernet port. So this patch
makes the inj_prefix and xtr_prefix variables apply only to the NPI
port (which the switchdev ocelot_vsc7514 driver does not use).

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
Changes in v4:
Patch is new.

 drivers/net/dsa/ocelot/felix.c             |  8 ++++----
 drivers/net/ethernet/mscc/ocelot.c         | 12 ++++++------
 drivers/net/ethernet/mscc/ocelot_vsc7514.c |  2 --
 include/soc/mscc/ocelot.h                  |  4 ++--
 4 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/drivers/net/dsa/ocelot/felix.c b/drivers/net/dsa/ocelot/felix.c
index 767cbdccdb3e..054e57dd4383 100644
--- a/drivers/net/dsa/ocelot/felix.c
+++ b/drivers/net/dsa/ocelot/felix.c
@@ -425,8 +425,8 @@ static int felix_init_structs(struct felix *felix, int num_phys_ports)
 	ocelot->num_mact_rows	= felix->info->num_mact_rows;
 	ocelot->vcap		= felix->info->vcap;
 	ocelot->ops		= felix->info->ops;
-	ocelot->inj_prefix	= OCELOT_TAG_PREFIX_SHORT;
-	ocelot->xtr_prefix	= OCELOT_TAG_PREFIX_SHORT;
+	ocelot->npi_inj_prefix	= OCELOT_TAG_PREFIX_SHORT;
+	ocelot->npi_xtr_prefix	= OCELOT_TAG_PREFIX_SHORT;
 	ocelot->devlink		= felix->ds->devlink;
 
 	port_phy_modes = kcalloc(num_phys_ports, sizeof(phy_interface_t),
@@ -541,9 +541,9 @@ static void felix_npi_port_init(struct ocelot *ocelot, int port)
 
 	/* NPI port Injection/Extraction configuration */
 	ocelot_fields_write(ocelot, port, SYS_PORT_MODE_INCL_XTR_HDR,
-			    ocelot->xtr_prefix);
+			    ocelot->npi_xtr_prefix);
 	ocelot_fields_write(ocelot, port, SYS_PORT_MODE_INCL_INJ_HDR,
-			    ocelot->inj_prefix);
+			    ocelot->npi_inj_prefix);
 
 	/* Disable transmission of pause frames */
 	ocelot_fields_write(ocelot, port, SYS_PAUSE_CFG_PAUSE_ENA, 0);
diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index 42d92a5b475d..acf7ef00e56b 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -1346,9 +1346,9 @@ void ocelot_port_set_maxlen(struct ocelot *ocelot, int port, size_t sdu)
 	if (port == ocelot->npi) {
 		maxlen += OCELOT_TAG_LEN;
 
-		if (ocelot->inj_prefix == OCELOT_TAG_PREFIX_SHORT)
+		if (ocelot->npi_inj_prefix == OCELOT_TAG_PREFIX_SHORT)
 			maxlen += OCELOT_SHORT_PREFIX_LEN;
-		else if (ocelot->inj_prefix == OCELOT_TAG_PREFIX_LONG)
+		else if (ocelot->npi_inj_prefix == OCELOT_TAG_PREFIX_LONG)
 			maxlen += OCELOT_LONG_PREFIX_LEN;
 	}
 
@@ -1378,9 +1378,9 @@ int ocelot_get_max_mtu(struct ocelot *ocelot, int port)
 	if (port == ocelot->npi) {
 		max_mtu -= OCELOT_TAG_LEN;
 
-		if (ocelot->inj_prefix == OCELOT_TAG_PREFIX_SHORT)
+		if (ocelot->npi_inj_prefix == OCELOT_TAG_PREFIX_SHORT)
 			max_mtu -= OCELOT_SHORT_PREFIX_LEN;
-		else if (ocelot->inj_prefix == OCELOT_TAG_PREFIX_LONG)
+		else if (ocelot->npi_inj_prefix == OCELOT_TAG_PREFIX_LONG)
 			max_mtu -= OCELOT_LONG_PREFIX_LEN;
 	}
 
@@ -1465,9 +1465,9 @@ static void ocelot_cpu_port_init(struct ocelot *ocelot)
 	ocelot_fields_write(ocelot, cpu, QSYS_SWITCH_PORT_MODE_PORT_ENA, 1);
 	/* CPU port Injection/Extraction configuration */
 	ocelot_fields_write(ocelot, cpu, SYS_PORT_MODE_INCL_XTR_HDR,
-			    ocelot->xtr_prefix);
+			    OCELOT_TAG_PREFIX_NONE);
 	ocelot_fields_write(ocelot, cpu, SYS_PORT_MODE_INCL_INJ_HDR,
-			    ocelot->inj_prefix);
+			    OCELOT_TAG_PREFIX_NONE);
 
 	/* Configure the CPU port to be VLAN aware */
 	ocelot_write_gix(ocelot, ANA_PORT_VLAN_CFG_VLAN_VID(0) |
diff --git a/drivers/net/ethernet/mscc/ocelot_vsc7514.c b/drivers/net/ethernet/mscc/ocelot_vsc7514.c
index 30a38df08a21..407244fe5b17 100644
--- a/drivers/net/ethernet/mscc/ocelot_vsc7514.c
+++ b/drivers/net/ethernet/mscc/ocelot_vsc7514.c
@@ -1347,8 +1347,6 @@ static int mscc_ocelot_probe(struct platform_device *pdev)
 	ocelot->num_flooding_pgids = 1;
 
 	ocelot->vcap = vsc7514_vcap_props;
-	ocelot->inj_prefix = OCELOT_TAG_PREFIX_NONE;
-	ocelot->xtr_prefix = OCELOT_TAG_PREFIX_NONE;
 	ocelot->npi = -1;
 
 	err = ocelot_init(ocelot);
diff --git a/include/soc/mscc/ocelot.h b/include/soc/mscc/ocelot.h
index cdc33fa05660..93c22627dedd 100644
--- a/include/soc/mscc/ocelot.h
+++ b/include/soc/mscc/ocelot.h
@@ -651,8 +651,8 @@ struct ocelot {
 
 	int				npi;
 
-	enum ocelot_tag_prefix		inj_prefix;
-	enum ocelot_tag_prefix		xtr_prefix;
+	enum ocelot_tag_prefix		npi_inj_prefix;
+	enum ocelot_tag_prefix		npi_xtr_prefix;
 
 	u32				*lags;
 
-- 
2.25.1