There are use cases for which the existing tagger, based on the NPI
(Node Processor Interface) functionality, is insufficient.

Namely:
- Frames injected through the NPI port bypass the frame analyzer, so no
  source address learning is performed, no TSN stream classification,
  etc.
- Flow control is not functional over an NPI port (PAUSE frames are
  encapsulated in the same Extraction Frame Header as all other frames)
- There can be at most one NPI port configured for an Ocelot switch. But
  in NXP LS1028A and T1040 there are two Ethernet CPU ports. The non-NPI
  port is currently either disabled, or operated as a plain user port
  (albeit an internally-facing one). Having the ability to configure the
  two CPU ports symmetrically could pave the way for e.g. creating a LAG
  between them, to increase bandwidth seamlessly for the system.

So, there is a desire to have an alternative to the NPI mode.

This patch brings an implementation of the software-defined tag_8021q.c
tagger format, which also preserves full functionality under a
vlan_filtering bridge (unlike sja1105, the only other user of
tag_8021q).

It does this by using the TCAM engines for:
- pushing the RX VLAN as a second, outer tag, on egress towards the CPU
  port
- redirecting towards the correct front port based on TX VLAN and
  popping that on egress

Signed-off-by: Vladimir Oltean <vladimir.olt...@nxp.com>
---
Changes in v2:
Clean up the hardcoding of random VCAP filter IDs and the inclusion of a
private ocelot header.

 MAINTAINERS                              |   1 +
 drivers/net/dsa/ocelot/Kconfig           |   4 +-
 drivers/net/dsa/ocelot/Makefile          |   5 +
 drivers/net/dsa/ocelot/felix.c           | 108 +++++++++++++--
 drivers/net/dsa/ocelot/felix.h           |   1 +
 drivers/net/dsa/ocelot/felix_tag_8021q.c | 166 +++++++++++++++++++++++
 drivers/net/dsa/ocelot/felix_tag_8021q.h |  20 +++
 drivers/net/ethernet/mscc/ocelot.c       |  18 ++-
 include/soc/mscc/ocelot.h                |   1 +
 net/dsa/Kconfig                          |  34 +++++
 net/dsa/Makefile                         |   3 +-
 net/dsa/tag_ocelot_8021q.c               |  61 +++++++++
 12 files changed, 399 insertions(+), 23 deletions(-)
 create mode 100644 drivers/net/dsa/ocelot/felix_tag_8021q.c
 create mode 100644 drivers/net/dsa/ocelot/felix_tag_8021q.h
 create mode 100644 net/dsa/tag_ocelot_8021q.c

diff --git a/MAINTAINERS b/MAINTAINERS
index a355db292486..a9cb0b659c00 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12736,6 +12736,7 @@ F:      drivers/net/dsa/ocelot/*
 F:     drivers/net/ethernet/mscc/
 F:     include/soc/mscc/ocelot*
 F:     net/dsa/tag_ocelot.c
+F:     net/dsa/tag_ocelot_8021q.c
 F:     tools/testing/selftests/drivers/net/ocelot/*
 
 OCXL (Open Coherent Accelerator Processor Interface OpenCAPI) DRIVER
diff --git a/drivers/net/dsa/ocelot/Kconfig b/drivers/net/dsa/ocelot/Kconfig
index c110e82a7973..ab8de14c4dae 100644
--- a/drivers/net/dsa/ocelot/Kconfig
+++ b/drivers/net/dsa/ocelot/Kconfig
@@ -2,11 +2,11 @@
 config NET_DSA_MSCC_FELIX
        tristate "Ocelot / Felix Ethernet switch support"
        depends on NET_DSA && PCI
+       depends on NET_DSA_TAG_OCELOT_NPI || NET_DSA_TAG_OCELOT_8021Q
        depends on NET_VENDOR_MICROSEMI
        depends on NET_VENDOR_FREESCALE
        depends on HAS_IOMEM
        select MSCC_OCELOT_SWITCH_LIB
-       select NET_DSA_TAG_OCELOT
        select FSL_ENETC_MDIO
        select PCS_LYNX
        help
@@ -16,10 +16,10 @@ config NET_DSA_MSCC_FELIX
 config NET_DSA_MSCC_SEVILLE
        tristate "Ocelot / Seville Ethernet switch support"
        depends on NET_DSA
+       depends on NET_DSA_TAG_OCELOT_NPI || NET_DSA_TAG_OCELOT_8021Q
        depends on NET_VENDOR_MICROSEMI
        depends on HAS_IOMEM
        select MSCC_OCELOT_SWITCH_LIB
-       select NET_DSA_TAG_OCELOT
        select PCS_LYNX
        help
          This driver supports the VSC9953 (Seville) switch, which is embedded
diff --git a/drivers/net/dsa/ocelot/Makefile b/drivers/net/dsa/ocelot/Makefile
index f6dd131e7491..e9ea8c0331d8 100644
--- a/drivers/net/dsa/ocelot/Makefile
+++ b/drivers/net/dsa/ocelot/Makefile
@@ -9,3 +9,8 @@ mscc_felix-objs := \
 mscc_seville-objs := \
        felix.o \
        seville_vsc9953.o
+
+ifdef CONFIG_NET_DSA_TAG_OCELOT_8021Q
+mscc_felix-objs += felix_tag_8021q.o
+mscc_seville-objs += felix_tag_8021q.o
+endif
diff --git a/drivers/net/dsa/ocelot/felix.c b/drivers/net/dsa/ocelot/felix.c
index 7dc230677b78..77f73c6bad0b 100644
--- a/drivers/net/dsa/ocelot/felix.c
+++ b/drivers/net/dsa/ocelot/felix.c
@@ -23,6 +23,7 @@
 #include <net/pkt_sched.h>
 #include <net/dsa.h>
 #include "felix.h"
+#include "felix_tag_8021q.h"
 
 static enum dsa_tag_protocol felix_get_tag_protocol(struct dsa_switch *ds,
                                                    int port,
@@ -439,6 +440,7 @@ static int felix_init_structs(struct felix *felix, int 
num_phys_ports)
 {
        struct ocelot *ocelot = &felix->ocelot;
        phy_interface_t *port_phy_modes;
+       enum ocelot_tag_prefix prefix;
        struct resource res;
        int port, i, err;
 
@@ -448,6 +450,11 @@ static int felix_init_structs(struct felix *felix, int 
num_phys_ports)
        if (!ocelot->ports)
                return -ENOMEM;
 
+       if (IS_ENABLED(CONFIG_NET_DSA_TAG_OCELOT_NPI))
+               prefix = OCELOT_TAG_PREFIX_SHORT;
+       else if (IS_ENABLED(CONFIG_NET_DSA_TAG_OCELOT_8021Q))
+               prefix = OCELOT_TAG_PREFIX_NONE;
+
        ocelot->map             = felix->info->map;
        ocelot->stats_layout    = felix->info->stats_layout;
        ocelot->num_stats       = felix->info->num_stats;
@@ -455,8 +462,8 @@ 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->inj_prefix      = prefix;
+       ocelot->xtr_prefix      = prefix;
 
        port_phy_modes = kcalloc(num_phys_ports, sizeof(phy_interface_t),
                                 GFP_KERNEL);
@@ -578,6 +585,15 @@ static void felix_npi_port_init(struct ocelot *ocelot, int 
port)
        ocelot_fields_write(ocelot, port, SYS_PAUSE_CFG_PAUSE_ENA, 0);
 }
 
+static void felix_8021q_cpu_port_init(struct ocelot *ocelot, int port)
+{
+       ocelot->dsa_8021q_cpu = port;
+
+       /* Overwrite PGID_CPU with the non-tagging port */
+       ocelot_write_rix(ocelot, BIT(ocelot->dsa_8021q_cpu),
+                        ANA_PGID_PGID, PGID_CPU);
+}
+
 /* Hardware initialization done here so that we can allocate structures with
  * devm without fear of dsa_register_switch returning -EPROBE_DEFER and causing
  * us to allocate structures twice (leak memory) and map PCI memory twice
@@ -587,7 +603,7 @@ static int felix_setup(struct dsa_switch *ds)
 {
        struct ocelot *ocelot = ds->priv;
        struct felix *felix = ocelot_to_felix(ocelot);
-       int port, err;
+       int port, cpu = -1, err;
 
        err = felix_init_structs(felix, ds->num_ports);
        if (err)
@@ -607,10 +623,20 @@ static int felix_setup(struct dsa_switch *ds)
        }
 
        for (port = 0; port < ds->num_ports; port++) {
+               if (dsa_is_unused_port(ds, port))
+                       continue;
+
                ocelot_init_port(ocelot, port);
 
-               if (dsa_is_cpu_port(ds, port))
-                       felix_npi_port_init(ocelot, port);
+               cpu = dsa_upstream_port(ds, port);
+               if (port == cpu)
+                       continue;
+
+               /* Allow forwarding to and from the CPU port */
+               ocelot_rmw_rix(ocelot, BIT(cpu), BIT(cpu),
+                              ANA_PGID_PGID, PGID_SRC + port);
+               ocelot_rmw_rix(ocelot, BIT(port), BIT(port),
+                              ANA_PGID_PGID, PGID_SRC + cpu);
 
                /* Set the default QoS Classification based on PCP and DEI
                 * bits of vlan tag.
@@ -618,14 +644,70 @@ static int felix_setup(struct dsa_switch *ds)
                felix_port_qos_map_init(ocelot, port);
        }
 
-       /* Include the CPU port module in the forwarding mask for unknown
-        * unicast - the hardware default value for ANA_FLOODING_FLD_UNICAST
-        * excludes BIT(ocelot->num_phys_ports), and so does ocelot_init, since
-        * Ocelot relies on whitelisting MAC addresses towards PGID_CPU.
-        */
-       ocelot_write_rix(ocelot,
-                        ANA_PGID_PGID_PGID(GENMASK(ocelot->num_phys_ports, 0)),
-                        ANA_PGID_PGID, PGID_UC);
+       if (IS_ENABLED(CONFIG_NET_DSA_TAG_OCELOT_NPI)) {
+               unsigned long flood_mask = BIT(ocelot->num_phys_ports);
+
+               felix_npi_port_init(ocelot, cpu);
+
+               /* Include the CPU port module (and indirectly, the NPI port)
+                * in the forwarding mask for unknown unicast - the hardware
+                * default value for ANA_FLOODING_FLD_UNICAST excludes
+                * BIT(ocelot->num_phys_ports), and so does ocelot_init,
+                * since Ocelot relies on whitelisting MAC addresses towards
+                * PGID_CPU.
+                * We do this because DSA does not yet perform RX filtering,
+                * and the NPI port does not perform source address learning,
+                * so traffic sent to Linux is effectively unknown from the
+                * switch's perspective.
+                */
+               for (port = 0; port < ds->num_ports; port++) {
+                       if (dsa_is_unused_port(ds, port))
+                               continue;
+
+                       flood_mask |= BIT(port);
+               }
+
+               ocelot_write_rix(ocelot, ANA_PGID_PGID_PGID(flood_mask),
+                                ANA_PGID_PGID, PGID_UC);
+       } else if (IS_ENABLED(CONFIG_NET_DSA_TAG_OCELOT_8021Q)) {
+               unsigned long flood_mask = 0;
+
+               felix_8021q_cpu_port_init(ocelot, cpu);
+
+               for (port = 0; port < ds->num_ports; port++) {
+                       if (dsa_is_unused_port(ds, port))
+                               continue;
+
+                       flood_mask |= BIT(port);
+
+                       /* This overwrites ocelot_init():
+                        * Do not forward BPDU frames to the CPU port module,
+                        * for 2 reasons:
+                        * - When these packets are injected from the tag_8021q
+                        *   CPU port, we want them to go out, not loop back
+                        *   into the system.
+                        * - STP traffic ingressing on a user port should go to
+                        *   the tag_8021q CPU port, not to the hardware CPU
+                        *   port module.
+                        */
+                       ocelot_write_gix(ocelot,
+                                        
ANA_PORT_CPU_FWD_BPDU_CFG_BPDU_REDIR_ENA(0),
+                                        ANA_PORT_CPU_FWD_BPDU_CFG, port);
+               }
+
+               /* In tag_8021q mode, the CPU port module is unused. So we
+                * want to disable flooding of any kind to the CPU port module
+                * (which is BIT(ocelot->num_phys_ports)).
+                */
+               ocelot_write_rix(ocelot, ANA_PGID_PGID_PGID(flood_mask),
+                                ANA_PGID_PGID, PGID_UC);
+               ocelot_write_rix(ocelot, ANA_PGID_PGID_PGID(flood_mask),
+                                ANA_PGID_PGID, PGID_MC);
+
+               err = felix_setup_8021q_tagging(ocelot);
+               if (err)
+                       return err;
+       }
 
        ds->mtu_enforcement_ingress = true;
        ds->configure_vlan_while_not_filtering = true;
diff --git a/drivers/net/dsa/ocelot/felix.h b/drivers/net/dsa/ocelot/felix.h
index 4c717324ac2f..71f343326c00 100644
--- a/drivers/net/dsa/ocelot/felix.h
+++ b/drivers/net/dsa/ocelot/felix.h
@@ -50,6 +50,7 @@ struct felix {
        struct lynx_pcs                 **pcs;
        resource_size_t                 switch_base;
        resource_size_t                 imdio_base;
+       struct dsa_8021q_context        *dsa_8021q_ctx;
 };
 
 struct net_device *felix_port_to_netdev(struct ocelot *ocelot, int port);
diff --git a/drivers/net/dsa/ocelot/felix_tag_8021q.c 
b/drivers/net/dsa/ocelot/felix_tag_8021q.c
new file mode 100644
index 000000000000..f209273bbf69
--- /dev/null
+++ b/drivers/net/dsa/ocelot/felix_tag_8021q.c
@@ -0,0 +1,166 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright 2020 NXP Semiconductors
+ *
+ * An implementation of the software-defined tag_8021q.c tagger format, which
+ * also preserves full functionality under a vlan_filtering bridge. It does
+ * this by using the TCAM engines for:
+ * - pushing the RX VLAN as a second, outer tag, on egress towards the CPU port
+ * - redirecting towards the correct front port based on TX VLAN and popping
+ *   that on egress
+ */
+#include <soc/mscc/ocelot_vcap.h>
+#include <linux/dsa/8021q.h>
+#include <linux/if_bridge.h>
+#include "felix.h"
+#include "felix_tag_8021q.h"
+
+static int felix_tag_8021q_rxvlan_add(struct ocelot *ocelot, int port, u16 vid,
+                                     bool pvid, bool untagged)
+{
+       const struct vcap_props *vcap = &ocelot->vcap[VCAP_ES0];
+       int key_length = vcap->keys[VCAP_ES0_IGR_PORT].length;
+       struct ocelot_vcap_filter *outer_tagging_rule;
+
+       /* We don't need to install the rxvlan into the other ports' filtering
+        * tables, because we're just pushing the rxvlan when sending towards
+        * the CPU
+        */
+       if (!pvid)
+               return 0;
+
+       outer_tagging_rule = kzalloc(sizeof(struct ocelot_vcap_filter),
+                                    GFP_KERNEL);
+       if (!outer_tagging_rule)
+               return -ENOMEM;
+
+       outer_tagging_rule->key_type = OCELOT_VCAP_KEY_ANY;
+       outer_tagging_rule->prio = 1;
+       outer_tagging_rule->id.cookie = port;
+       outer_tagging_rule->id.tc_offload = false;
+       outer_tagging_rule->block_id = VCAP_ES0;
+       outer_tagging_rule->type = OCELOT_VCAP_FILTER_OFFLOAD;
+       outer_tagging_rule->lookup = 0;
+       outer_tagging_rule->ingress_port.value = port;
+       outer_tagging_rule->ingress_port.mask = GENMASK(key_length - 1, 0);
+       outer_tagging_rule->egress_port.value = ocelot->dsa_8021q_cpu;
+       outer_tagging_rule->egress_port.mask = GENMASK(key_length - 1, 0);
+       outer_tagging_rule->action.push_outer_tag = OCELOT_ES0_TAG;
+       outer_tagging_rule->action.tag_a_tpid_sel = OCELOT_TAG_TPID_SEL_8021AD;
+       outer_tagging_rule->action.tag_a_vid_sel = 1;
+       outer_tagging_rule->action.vid_a_val = vid;
+
+       return ocelot_vcap_filter_add(ocelot, outer_tagging_rule, NULL);
+}
+
+static int felix_tag_8021q_txvlan_add(struct ocelot *ocelot, int port, u16 vid,
+                                     bool pvid, bool untagged)
+{
+       struct ocelot_vcap_filter *untagging_rule;
+       struct ocelot_vcap_filter *redirect_rule;
+       int ret;
+
+       /* tag_8021q.c assumes we are implementing this via port VLAN
+        * membership, which we aren't. So we don't need to add any VCAP filter
+        * for the CPU port.
+        */
+       if (port == ocelot->dsa_8021q_cpu)
+               return 0;
+
+       untagging_rule = kzalloc(sizeof(struct ocelot_vcap_filter), GFP_KERNEL);
+       if (!untagging_rule)
+               return -ENOMEM;
+
+       redirect_rule = kzalloc(sizeof(struct ocelot_vcap_filter), GFP_KERNEL);
+       if (!redirect_rule) {
+               kfree(untagging_rule);
+               return -ENOMEM;
+       }
+
+       untagging_rule->key_type = OCELOT_VCAP_KEY_ANY;
+       untagging_rule->ingress_port_mask = BIT(ocelot->dsa_8021q_cpu);
+       untagging_rule->vlan.vid.value = vid;
+       untagging_rule->vlan.vid.mask = VLAN_VID_MASK;
+       untagging_rule->prio = 1;
+       untagging_rule->id.cookie = port;
+       untagging_rule->id.tc_offload = false;
+       untagging_rule->block_id = VCAP_IS1;
+       untagging_rule->type = OCELOT_VCAP_FILTER_OFFLOAD;
+       untagging_rule->lookup = 0;
+       untagging_rule->action.vlan_pop_cnt_ena = true;
+       untagging_rule->action.vlan_pop_cnt = 1;
+       untagging_rule->action.pag_override_mask = 0xff;
+       untagging_rule->action.pag_val = port;
+
+       ret = ocelot_vcap_filter_add(ocelot, untagging_rule, NULL);
+       if (ret) {
+               kfree(untagging_rule);
+               kfree(redirect_rule);
+               return ret;
+       }
+
+       redirect_rule->key_type = OCELOT_VCAP_KEY_ANY;
+       redirect_rule->ingress_port_mask = BIT(ocelot->dsa_8021q_cpu);
+       redirect_rule->pag = port;
+       redirect_rule->prio = 1;
+       redirect_rule->id.cookie = port;
+       redirect_rule->id.tc_offload = false;
+       redirect_rule->block_id = VCAP_IS2;
+       redirect_rule->type = OCELOT_VCAP_FILTER_OFFLOAD;
+       redirect_rule->lookup = 0;
+       redirect_rule->action.mask_mode = OCELOT_MASK_MODE_REDIRECT;
+       redirect_rule->action.port_mask = BIT(port);
+
+       ret = ocelot_vcap_filter_add(ocelot, redirect_rule, NULL);
+       if (ret) {
+               ocelot_vcap_filter_del(ocelot, untagging_rule);
+               kfree(redirect_rule);
+               return ret;
+       }
+
+       return 0;
+}
+
+static int felix_tag_8021q_vlan_add(struct dsa_switch *ds, int port, u16 vid,
+                                   u16 flags)
+{
+       bool untagged = flags & BRIDGE_VLAN_INFO_UNTAGGED;
+       bool pvid = flags & BRIDGE_VLAN_INFO_PVID;
+       struct ocelot *ocelot = ds->priv;
+
+       if (vid_is_dsa_8021q_rxvlan(vid))
+               return felix_tag_8021q_rxvlan_add(ocelot, port, vid, pvid,
+                                                 untagged);
+
+       if (vid_is_dsa_8021q_txvlan(vid))
+               return felix_tag_8021q_txvlan_add(ocelot, port, vid, pvid,
+                                                 untagged);
+
+       return 0;
+}
+
+static const struct dsa_8021q_ops felix_tag_8021q_ops = {
+       .vlan_add       = felix_tag_8021q_vlan_add,
+};
+
+int felix_setup_8021q_tagging(struct ocelot *ocelot)
+{
+       struct felix *felix = ocelot_to_felix(ocelot);
+       struct dsa_switch *ds = felix->ds;
+       int ret;
+
+       felix->dsa_8021q_ctx = devm_kzalloc(ds->dev,
+                                           sizeof(*felix->dsa_8021q_ctx),
+                                           GFP_KERNEL);
+       if (!felix->dsa_8021q_ctx)
+               return -ENOMEM;
+
+       felix->dsa_8021q_ctx->ops = &felix_tag_8021q_ops;
+       felix->dsa_8021q_ctx->proto = htons(ETH_P_8021AD);
+       felix->dsa_8021q_ctx->ds = ds;
+
+       rtnl_lock();
+       ret = dsa_8021q_setup(felix->dsa_8021q_ctx, true);
+       rtnl_unlock();
+
+       return ret;
+}
diff --git a/drivers/net/dsa/ocelot/felix_tag_8021q.h 
b/drivers/net/dsa/ocelot/felix_tag_8021q.h
new file mode 100644
index 000000000000..47684a18c96e
--- /dev/null
+++ b/drivers/net/dsa/ocelot/felix_tag_8021q.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright 2020 NXP Semiconductors
+ */
+#ifndef _MSCC_FELIX_TAG_8021Q_H
+#define _MSCC_FELIX_TAG_8021Q_H
+
+#if IS_ENABLED(CONFIG_NET_DSA_TAG_OCELOT_8021Q)
+
+int felix_setup_8021q_tagging(struct ocelot *ocelot);
+
+#else
+
+static inline int felix_setup_8021q_tagging(struct ocelot *ocelot)
+{
+       return -EOPNOTSUPP;
+}
+
+#endif /* IS_ENABLED(CONFIG_NET_DSA_TAG_OCELOT_8021Q) */
+
+#endif /* _MSCC_FELIX_TAG_8021Q_H */
diff --git a/drivers/net/ethernet/mscc/ocelot.c 
b/drivers/net/ethernet/mscc/ocelot.c
index 0b9992bd6626..be4671bfe95f 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -911,8 +911,13 @@ void ocelot_bridge_stp_state_set(struct ocelot *ocelot, 
int port, u8 state)
         * a source for the other ports.
         */
        for (p = 0; p < ocelot->num_phys_ports; p++) {
+               unsigned long mask = 0;
+
+               if (p == ocelot->dsa_8021q_cpu)
+                       continue;
+
                if (ocelot->bridge_fwd_mask & BIT(p)) {
-                       unsigned long mask = ocelot->bridge_fwd_mask & ~BIT(p);
+                       mask = ocelot->bridge_fwd_mask & ~BIT(p);
 
                        for (i = 0; i < ocelot->num_phys_ports; i++) {
                                unsigned long bond_mask = ocelot->lags[i];
@@ -925,13 +930,12 @@ void ocelot_bridge_stp_state_set(struct ocelot *ocelot, 
int port, u8 state)
                                        break;
                                }
                        }
-
-                       ocelot_write_rix(ocelot, mask,
-                                        ANA_PGID_PGID, PGID_SRC + p);
-               } else {
-                       ocelot_write_rix(ocelot, 0,
-                                        ANA_PGID_PGID, PGID_SRC + p);
                }
+
+               if (ocelot->dsa_8021q_cpu >= 0)
+                       mask |= ocelot->dsa_8021q_cpu;
+
+               ocelot_write_rix(ocelot, mask, ANA_PGID_PGID, PGID_SRC + p);
        }
 }
 EXPORT_SYMBOL(ocelot_bridge_stp_state_set);
diff --git a/include/soc/mscc/ocelot.h b/include/soc/mscc/ocelot.h
index 2f4cd3288bcc..4cbb7655ef0c 100644
--- a/include/soc/mscc/ocelot.h
+++ b/include/soc/mscc/ocelot.h
@@ -631,6 +631,7 @@ struct ocelot {
        u8                              num_phys_ports;
 
        int                             npi;
+       int                             dsa_8021q_cpu;
 
        enum ocelot_tag_prefix          inj_prefix;
        enum ocelot_tag_prefix          xtr_prefix;
diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
index dfecd7b22fd7..a4ff1385d270 100644
--- a/net/dsa/Kconfig
+++ b/net/dsa/Kconfig
@@ -111,6 +111,40 @@ config NET_DSA_TAG_OCELOT
          Say Y or M if you want to enable support for tagging frames for the
          Ocelot switches (VSC7511, VSC7512, VSC7513, VSC7514, VSC9959).
 
+choice
+       prompt "Tagging format"
+       depends on NET_DSA_TAG_OCELOT
+       default NET_DSA_TAG_OCELOT_NPI
+       help
+         Choose the tagging format for frames delivered by the Ocelot
+         switches to the CPU.
+
+config NET_DSA_TAG_OCELOT_NPI
+       bool "Native tagging over NPI"
+       help
+         Say Y if you want to enable NPI tagging for the Ocelot switches.
+         In this mode, the frames over the Ethernet CPU port are prepended
+         with a hardware-defined injection/extraction frame header.
+         Flow control (PAUSE frames) over the CPU port is not supported
+         when operating in this mode.
+
+         If unsure, say Y.
+
+config NET_DSA_TAG_OCELOT_8021Q
+       bool "VLAN-based tagging"
+       select NET_DSA_TAG_8021Q
+       help
+         Say Y if you want to enable support for tagging frames with a custom
+         VLAN-based header. Frames that require timestamping, such as PTP, are
+         not delivered over Ethernet but over register-based MMIO. Flow
+         control over the CPU port is functional in this mode. When using this
+         mode, less TCAM resources (VCAP IS1, IS2, ES0) are available for use
+         with tc-flower.
+
+         If unsure, say N.
+
+endchoice
+
 config NET_DSA_TAG_QCA
        tristate "Tag driver for Qualcomm Atheros QCA8K switches"
        help
diff --git a/net/dsa/Makefile b/net/dsa/Makefile
index 0fb2b75a7ae3..0e0d828fec51 100644
--- a/net/dsa/Makefile
+++ b/net/dsa/Makefile
@@ -14,7 +14,8 @@ obj-$(CONFIG_NET_DSA_TAG_KSZ) += tag_ksz.o
 obj-$(CONFIG_NET_DSA_TAG_RTL4_A) += tag_rtl4_a.o
 obj-$(CONFIG_NET_DSA_TAG_LAN9303) += tag_lan9303.o
 obj-$(CONFIG_NET_DSA_TAG_MTK) += tag_mtk.o
-obj-$(CONFIG_NET_DSA_TAG_OCELOT) += tag_ocelot.o
+obj-$(CONFIG_NET_DSA_TAG_OCELOT_NPI) += tag_ocelot.o
+obj-$(CONFIG_NET_DSA_TAG_OCELOT_8021Q) += tag_ocelot_8021q.o
 obj-$(CONFIG_NET_DSA_TAG_QCA) += tag_qca.o
 obj-$(CONFIG_NET_DSA_TAG_SJA1105) += tag_sja1105.o
 obj-$(CONFIG_NET_DSA_TAG_TRAILER) += tag_trailer.o
diff --git a/net/dsa/tag_ocelot_8021q.c b/net/dsa/tag_ocelot_8021q.c
new file mode 100644
index 000000000000..fa89c6a5bb7d
--- /dev/null
+++ b/net/dsa/tag_ocelot_8021q.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright 2020 NXP Semiconductors
+ */
+#include <linux/dsa/8021q.h>
+#include "dsa_priv.h"
+
+static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
+                                  struct net_device *netdev)
+{
+       struct dsa_port *dp = dsa_slave_to_port(netdev);
+       u16 tx_vid = dsa_8021q_tx_vid(dp->ds, dp->index);
+       u16 queue_mapping = skb_get_queue_mapping(skb);
+       u8 pcp = netdev_txq_to_tc(netdev, queue_mapping);
+
+       return dsa_8021q_xmit(skb, netdev, ETH_P_8021Q,
+                             ((pcp << VLAN_PRIO_SHIFT) | tx_vid));
+}
+
+static struct sk_buff *ocelot_rcv(struct sk_buff *skb,
+                                 struct net_device *netdev,
+                                 struct packet_type *pt)
+{
+       int src_port, switch_id, qos_class;
+       u16 vid, tci;
+
+       skb_push_rcsum(skb, ETH_HLEN);
+       if (skb_vlan_tag_present(skb)) {
+               tci = skb_vlan_tag_get(skb);
+               __vlan_hwaccel_clear_tag(skb);
+       } else {
+               __skb_vlan_pop(skb, &tci);
+       }
+       skb_pull_rcsum(skb, ETH_HLEN);
+
+       vid = tci & VLAN_VID_MASK;
+       src_port = dsa_8021q_rx_source_port(vid);
+       switch_id = dsa_8021q_rx_switch_id(vid);
+       qos_class = (tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
+
+       skb->dev = dsa_master_find_slave(netdev, switch_id, src_port);
+       if (!skb->dev)
+               return NULL;
+
+       skb->offload_fwd_mark = 1;
+       skb->priority = qos_class;
+
+       return skb;
+}
+
+static struct dsa_device_ops ocelot_netdev_ops = {
+       .name                   = "ocelot",
+       .proto                  = DSA_TAG_PROTO_OCELOT,
+       .xmit                   = ocelot_xmit,
+       .rcv                    = ocelot_rcv,
+       .overhead               = VLAN_HLEN,
+};
+
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_OCELOT);
+
+module_dsa_tag_driver(ocelot_netdev_ops);
-- 
2.25.1

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