Merge branch 'PTP-support-for-the-SJA1105-DSA-driver'

Vladimir Oltean says:

====================
PTP support for the SJA1105 DSA driver

This patchset adds the following:

 - A timecounter/cyclecounter based PHC for the free-running
   timestamping clock of this switch.

 - A state machine implemented in the DSA tagger for SJA1105, which
   keeps track of metadata follow-up Ethernet frames (the switch's way
   of transmitting RX timestamps).

Clock manipulations on the actual hardware PTP clock will have to be
implemented anyway, for the TTEthernet block and the time-based ingress
policer.

v3 patchset can be found at:
https://lkml.org/lkml/2019/6/4/954

Changes from v3:

- Made it compile with the SJA1105 DSA driver and PTP driver as modules.

- Reworked/simplified/fixed some issues in 03/17
  (dsa_8021q_remove_header) and added an ASCII image that
  illustrates the transformation that is taking place.

- Removed a useless check for sja1105_is_link_local from 16/17 (RX
  timestamping) which also made previous 08/17 patch ("Move
  sja1105_is_link_local to include/linux") useless and therefore dropped.

v2 patchset can be found at:
https://lkml.org/lkml/2019/6/2/146

Changes from v2:

- Broke previous 09/10 patch (timestamping) into multiple smaller
  patches.

- Every patch in the series compiles.

v1 patchset can be found at:
https://lkml.org/lkml/2019/5/28/1093

Changes from v1:

- Removed the addition of the DSA .can_timestamp callback.

- Waiting for meta frames is done completely inside the tagger, and all
  frames emitted on RX are already partially timestamped.

- Added a global data structure for the tagger common to all ports.

- Made PTP work with ports in standalone mode, by limiting use of the
  DMAC-mangling "incl_srcpt" mode only when ports are bridged, aka when
  the DSA master is already promiscuous and can receive anything.
  Also changed meta frames to be sent at the 01-80-C2-00-00-0E DMAC.

- Made some progress w.r.t. observed negative path delay.  Apparently it
  only appears when the delay mechanism is the delay request-response
  (end-to-end) one. If peer delay is used (-P), the path delay is
  positive and appears reasonable for an 1000Base-T link (485 ns in
  steady state).

  SJA1105 as PTP slave (OC) with E2E path delay:

ptp4l[55.600]: master offset          8 s2 freq  +83677 path delay     -2390
ptp4l[56.600]: master offset         17 s2 freq  +83688 path delay     -2391
ptp4l[57.601]: master offset          6 s2 freq  +83682 path delay     -2391
ptp4l[58.601]: master offset         -1 s2 freq  +83677 path delay     -2391

  SJA1105 as PTP slave (OC) with P2P path delay:

ptp4l[48.343]: master offset          5 s2 freq  +83715 path delay       484
ptp4l[48.468]: master offset         -3 s2 freq  +83705 path delay       485
ptp4l[48.593]: master offset          0 s2 freq  +83708 path delay       485
ptp4l[48.718]: master offset          1 s2 freq  +83710 path delay       485
ptp4l[48.844]: master offset          1 s2 freq  +83710 path delay       485
ptp4l[48.969]: master offset         -5 s2 freq  +83702 path delay       485
ptp4l[49.094]: master offset          3 s2 freq  +83712 path delay       485
ptp4l[49.219]: master offset          4 s2 freq  +83714 path delay       485
ptp4l[49.344]: master offset         -5 s2 freq  +83702 path delay       485
ptp4l[49.469]: master offset          3 s2 freq  +83713 path delay       487
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/sja1105/Kconfig

@@ -16,3 +16,10 @@ tristate "NXP SJA1105 Ethernet switch family support"
 	    - SJA1105Q (Gen. 2, No SGMII, TT-Ethernet)
 	    - SJA1105R (Gen. 2, SGMII, No TT-Ethernet)
 	    - SJA1105S (Gen. 2, SGMII, TT-Ethernet)
+
+config NET_DSA_SJA1105_PTP
+tristate "Support for the PTP clock on the NXP SJA1105 Ethernet switch"
+	depends on NET_DSA_SJA1105
+	help
+	  This enables support for timestamping and PTP clock manipulations in
+	  the SJA1105 DSA driver.

drivers/net/dsa/sja1105/Makefile

 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_NET_DSA_SJA1105) += sja1105.o
+obj-$(CONFIG_NET_DSA_SJA1105_PTP) += sja1105_ptp.o
 
 sja1105-objs := \
     sja1105_spi.o \

drivers/net/dsa/sja1105/sja1105.h

@@ -5,6 +5,8 @@
 #ifndef _SJA1105_H
 #define _SJA1105_H
 
+#include <linux/ptp_clock_kernel.h>
+#include <linux/timecounter.h>
 #include <linux/dsa/sja1105.h>
 #include <net/dsa.h>
 #include <linux/mutex.h>
@@ -27,6 +29,11 @@ struct sja1105_regs {
 	u64 rgu;
 	u64 config;
 	u64 rmii_pll1;
+	u64 ptp_control;
+	u64 ptpclk;
+	u64 ptpclkrate;
+	u64 ptptsclk;
+	u64 ptpegr_ts[SJA1105_NUM_PORTS];
 	u64 pad_mii_tx[SJA1105_NUM_PORTS];
 	u64 cgu_idiv[SJA1105_NUM_PORTS];
 	u64 rgmii_pad_mii_tx[SJA1105_NUM_PORTS];
@@ -50,9 +57,19 @@ struct sja1105_info {
 	 * switch core and device_id)
 	 */
 	u64 part_no;
+	/* E/T and P/Q/R/S have partial timestamps of different sizes.
+	 * They must be reconstructed on both families anyway to get the full
+	 * 64-bit values back.
+	 */
+	int ptp_ts_bits;
+	/* Also SPI commands are of different sizes to retrieve
+	 * the egress timestamps.
+	 */
+	int ptpegr_ts_bytes;
 	const struct sja1105_dynamic_table_ops *dyn_ops;
 	const struct sja1105_table_ops *static_ops;
 	const struct sja1105_regs *regs;
+	int (*ptp_cmd)(const void *ctx, const void *data);
 	int (*reset_cmd)(const void *ctx, const void *data);
 	int (*setup_rgmii_delay)(const void *ctx, int port);
 	/* Prototypes from include/net/dsa.h */
@@ -72,13 +89,25 @@ struct sja1105_private {
 	struct spi_device *spidev;
 	struct dsa_switch *ds;
 	struct sja1105_port ports[SJA1105_NUM_PORTS];
+	struct ptp_clock_info ptp_caps;
+	struct ptp_clock *clock;
+	/* The cycle counter translates the PTP timestamps (based on
+	 * a free-running counter) into a software time domain.
+	 */
+	struct cyclecounter tstamp_cc;
+	struct timecounter tstamp_tc;
+	struct delayed_work refresh_work;
+	/* Serializes all operations on the cycle counter */
+	struct mutex ptp_lock;
 	/* Serializes transmission of management frames so that
 	 * the switch doesn't confuse them with one another.
 	 */
 	struct mutex mgmt_lock;
+	struct sja1105_tagger_data tagger_data;
 };
 
 #include "sja1105_dynamic_config.h"
+#include "sja1105_ptp.h"
 
 struct sja1105_spi_message {
 	u64 access;

drivers/net/dsa/sja1105/sja1105_dynamic_config.c

@@ -378,6 +378,7 @@ struct sja1105_dynamic_table_ops sja1105et_dyn_ops[BLK_IDX_MAX_DYN] = {
 		.addr = 0x38,
 	},
 	[BLK_IDX_L2_FORWARDING_PARAMS] = {0},
+	[BLK_IDX_AVB_PARAMS] = {0},
 	[BLK_IDX_GENERAL_PARAMS] = {
 		.entry_packing = sja1105et_general_params_entry_packing,
 		.cmd_packing = sja1105et_general_params_cmd_packing,
@@ -441,6 +442,7 @@ struct sja1105_dynamic_table_ops sja1105pqrs_dyn_ops[BLK_IDX_MAX_DYN] = {
 		.addr = 0x38,
 	},
 	[BLK_IDX_L2_FORWARDING_PARAMS] = {0},
+	[BLK_IDX_AVB_PARAMS] = {0},
 	[BLK_IDX_GENERAL_PARAMS] = {
 		.entry_packing = sja1105et_general_params_entry_packing,
 		.cmd_packing = sja1105et_general_params_cmd_packing,

drivers/net/dsa/sja1105/sja1105_main.c

@@ -389,14 +389,14 @@ static int sja1105_init_general_params(struct sja1105_private *priv)
 		.mirr_ptacu = 0,
 		.switchid = priv->ds->index,
 		/* Priority queue for link-local frames trapped to CPU */
-		.hostprio = 0,
+		.hostprio = 7,
 		.mac_fltres1 = SJA1105_LINKLOCAL_FILTER_A,
 		.mac_flt1    = SJA1105_LINKLOCAL_FILTER_A_MASK,
-		.incl_srcpt1 = true,
+		.incl_srcpt1 = false,
 		.send_meta1  = false,
 		.mac_fltres0 = SJA1105_LINKLOCAL_FILTER_B,
 		.mac_flt0    = SJA1105_LINKLOCAL_FILTER_B_MASK,
-		.incl_srcpt0 = true,
+		.incl_srcpt0 = false,
 		.send_meta0  = false,
 		/* The destination for traffic matching mac_fltres1 and
 		 * mac_fltres0 on all ports except host_port. Such traffic
@@ -508,6 +508,39 @@ static int sja1105_init_l2_policing(struct sja1105_private *priv)
 	return 0;
 }
 
+static int sja1105_init_avb_params(struct sja1105_private *priv,
+				   bool on)
+{
+	struct sja1105_avb_params_entry *avb;
+	struct sja1105_table *table;
+
+	table = &priv->static_config.tables[BLK_IDX_AVB_PARAMS];
+
+	/* Discard previous AVB Parameters Table */
+	if (table->entry_count) {
+		kfree(table->entries);
+		table->entry_count = 0;
+	}
+
+	/* Configure the reception of meta frames only if requested */
+	if (!on)
+		return 0;
+
+	table->entries = kcalloc(SJA1105_MAX_AVB_PARAMS_COUNT,
+				 table->ops->unpacked_entry_size, GFP_KERNEL);
+	if (!table->entries)
+		return -ENOMEM;
+
+	table->entry_count = SJA1105_MAX_AVB_PARAMS_COUNT;
+
+	avb = table->entries;
+
+	avb->destmeta = SJA1105_META_DMAC;
+	avb->srcmeta  = SJA1105_META_SMAC;
+
+	return 0;
+}
+
 static int sja1105_static_config_load(struct sja1105_private *priv,
 				      struct sja1105_dt_port *ports)
 {
@@ -546,6 +579,9 @@ static int sja1105_static_config_load(struct sja1105_private *priv,
 	if (rc < 0)
 		return rc;
 	rc = sja1105_init_general_params(priv);
+	if (rc < 0)
+		return rc;
+	rc = sja1105_init_avb_params(priv, false);
 	if (rc < 0)
 		return rc;
 
@@ -1289,23 +1325,6 @@ static int sja1105_static_config_reload(struct sja1105_private *priv)
 	return rc;
 }
 
-/* The TPID setting belongs to the General Parameters table,
- * which can only be partially reconfigured at runtime (and not the TPID).
- * So a switch reset is required.
- */
-static int sja1105_change_tpid(struct sja1105_private *priv,
-			       u16 tpid, u16 tpid2)
-{
-	struct sja1105_general_params_entry *general_params;
-	struct sja1105_table *table;
-
-	table = &priv->static_config.tables[BLK_IDX_GENERAL_PARAMS];
-	general_params = table->entries;
-	general_params->tpid = tpid;
-	general_params->tpid2 = tpid2;
-	return sja1105_static_config_reload(priv);
-}
-
 static int sja1105_pvid_apply(struct sja1105_private *priv, int port, u16 pvid)
 {
 	struct sja1105_mac_config_entry *mac;
@@ -1424,17 +1443,41 @@ static int sja1105_vlan_prepare(struct dsa_switch *ds, int port,
 	return 0;
 }
 
+/* The TPID setting belongs to the General Parameters table,
+ * which can only be partially reconfigured at runtime (and not the TPID).
+ * So a switch reset is required.
+ */
 static int sja1105_vlan_filtering(struct dsa_switch *ds, int port, bool enabled)
 {
+	struct sja1105_general_params_entry *general_params;
 	struct sja1105_private *priv = ds->priv;
+	struct sja1105_table *table;
+	u16 tpid, tpid2;
 	int rc;
 
-	if (enabled)
+	if (enabled) {
 		/* Enable VLAN filtering. */
-		rc = sja1105_change_tpid(priv, ETH_P_8021Q, ETH_P_8021AD);
-	else
+		tpid  = ETH_P_8021AD;
+		tpid2 = ETH_P_8021Q;
+	} else {
 		/* Disable VLAN filtering. */
-		rc = sja1105_change_tpid(priv, ETH_P_SJA1105, ETH_P_SJA1105);
+		tpid  = ETH_P_SJA1105;
+		tpid2 = ETH_P_SJA1105;
+	}
+
+	table = &priv->static_config.tables[BLK_IDX_GENERAL_PARAMS];
+	general_params = table->entries;
+	/* EtherType used to identify outer tagged (S-tag) VLAN traffic */
+	general_params->tpid = tpid;
+	/* EtherType used to identify inner tagged (C-tag) VLAN traffic */
+	general_params->tpid2 = tpid2;
+	/* When VLAN filtering is on, we need to at least be able to
+	 * decode management traffic through the "backup plan".
+	 */
+	general_params->incl_srcpt1 = enabled;
+	general_params->incl_srcpt0 = enabled;
+
+	rc = sja1105_static_config_reload(priv);
 	if (rc)
 		dev_err(ds->dev, "Failed to change VLAN Ethertype\n");
 
@@ -1523,6 +1566,11 @@ static int sja1105_setup(struct dsa_switch *ds)
 		return rc;
 	}
 
+	rc = sja1105_ptp_clock_register(priv);
+	if (rc < 0) {
+		dev_err(ds->dev, "Failed to register PTP clock: %d\n", rc);
+		return rc;
+	}
 	/* Create and send configuration down to device */
 	rc = sja1105_static_config_load(priv, ports);
 	if (rc < 0) {
@@ -1552,8 +1600,16 @@ static int sja1105_setup(struct dsa_switch *ds)
 	return sja1105_setup_8021q_tagging(ds, true);
 }
 
+static void sja1105_teardown(struct dsa_switch *ds)
+{
+	struct sja1105_private *priv = ds->priv;
+
+	cancel_work_sync(&priv->tagger_data.rxtstamp_work);
+	skb_queue_purge(&priv->tagger_data.skb_rxtstamp_queue);
+}
+
 static int sja1105_mgmt_xmit(struct dsa_switch *ds, int port, int slot,
-			     struct sk_buff *skb)
+			     struct sk_buff *skb, bool takets)
 {
 	struct sja1105_mgmt_entry mgmt_route = {0};
 	struct sja1105_private *priv = ds->priv;
@@ -1566,6 +1622,8 @@ static int sja1105_mgmt_xmit(struct dsa_switch *ds, int port, int slot,
 	mgmt_route.macaddr = ether_addr_to_u64(hdr->h_dest);
 	mgmt_route.destports = BIT(port);
 	mgmt_route.enfport = 1;
+	mgmt_route.tsreg = 0;
+	mgmt_route.takets = takets;
 
 	rc = sja1105_dynamic_config_write(priv, BLK_IDX_MGMT_ROUTE,
 					  slot, &mgmt_route, true);
@@ -1617,7 +1675,11 @@ static netdev_tx_t sja1105_port_deferred_xmit(struct dsa_switch *ds, int port,
 {
 	struct sja1105_private *priv = ds->priv;
 	struct sja1105_port *sp = &priv->ports[port];
+	struct skb_shared_hwtstamps shwt = {0};
 	int slot = sp->mgmt_slot;
+	struct sk_buff *clone;
+	u64 now, ts;
+	int rc;
 
 	/* The tragic fact about the switch having 4x2 slots for installing
 	 * management routes is that all of them except one are actually
@@ -1635,8 +1697,36 @@ static netdev_tx_t sja1105_port_deferred_xmit(struct dsa_switch *ds, int port,
 	 */
 	mutex_lock(&priv->mgmt_lock);
 
-	sja1105_mgmt_xmit(ds, port, slot, skb);
+	/* The clone, if there, was made by dsa_skb_tx_timestamp */
+	clone = DSA_SKB_CB(skb)->clone;
+
+	sja1105_mgmt_xmit(ds, port, slot, skb, !!clone);
+
+	if (!clone)
+		goto out;
+
+	skb_shinfo(clone)->tx_flags |= SKBTX_IN_PROGRESS;
+
+	mutex_lock(&priv->ptp_lock);
+
+	now = priv->tstamp_cc.read(&priv->tstamp_cc);
+
+	rc = sja1105_ptpegr_ts_poll(priv, slot, &ts);
+	if (rc < 0) {
+		dev_err(ds->dev, "xmit: timed out polling for tstamp\n");
+		kfree_skb(clone);
+		goto out_unlock_ptp;
+	}
+
+	ts = sja1105_tstamp_reconstruct(priv, now, ts);
+	ts = timecounter_cyc2time(&priv->tstamp_tc, ts);
+
+	shwt.hwtstamp = ns_to_ktime(ts);
+	skb_complete_tx_timestamp(clone, &shwt);
 
+out_unlock_ptp:
+	mutex_unlock(&priv->ptp_lock);
+out:
 	mutex_unlock(&priv->mgmt_lock);
 	return NETDEV_TX_OK;
 }
@@ -1665,15 +1755,178 @@ static int sja1105_set_ageing_time(struct dsa_switch *ds,
 	return sja1105_static_config_reload(priv);
 }
 
+/* Caller must hold priv->tagger_data.meta_lock */
+static int sja1105_change_rxtstamping(struct sja1105_private *priv,
+				      bool on)
+{
+	struct sja1105_general_params_entry *general_params;
+	struct sja1105_table *table;
+	int rc;
+
+	table = &priv->static_config.tables[BLK_IDX_GENERAL_PARAMS];
+	general_params = table->entries;
+	general_params->send_meta1 = on;
+	general_params->send_meta0 = on;
+
+	rc = sja1105_init_avb_params(priv, on);
+	if (rc < 0)
+		return rc;
+
+	/* Initialize the meta state machine to a known state */
+	if (priv->tagger_data.stampable_skb) {
+		kfree_skb(priv->tagger_data.stampable_skb);
+		priv->tagger_data.stampable_skb = NULL;
+	}
+
+	return sja1105_static_config_reload(priv);
+}
+
+static int sja1105_hwtstamp_set(struct dsa_switch *ds, int port,
+				struct ifreq *ifr)
+{
+	struct sja1105_private *priv = ds->priv;
+	struct hwtstamp_config config;
+	bool rx_on;
+	int rc;
+
+	if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
+		return -EFAULT;
+
+	switch (config.tx_type) {
+	case HWTSTAMP_TX_OFF:
+		priv->ports[port].hwts_tx_en = false;
+		break;
+	case HWTSTAMP_TX_ON:
+		priv->ports[port].hwts_tx_en = true;
+		break;
+	default:
+		return -ERANGE;
+	}
+
+	switch (config.rx_filter) {
+	case HWTSTAMP_FILTER_NONE:
+		rx_on = false;
+		break;
+	default:
+		rx_on = true;
+		break;
+	}
+
+	if (rx_on != priv->tagger_data.hwts_rx_en) {
+		spin_lock(&priv->tagger_data.meta_lock);
+		rc = sja1105_change_rxtstamping(priv, rx_on);
+		spin_unlock(&priv->tagger_data.meta_lock);
+		if (rc < 0) {
+			dev_err(ds->dev,
+				"Failed to change RX timestamping: %d\n", rc);
+			return -EFAULT;
+		}
+		priv->tagger_data.hwts_rx_en = rx_on;
+	}
+
+	if (copy_to_user(ifr->ifr_data, &config, sizeof(config)))
+		return -EFAULT;
+	return 0;
+}
+
+static int sja1105_hwtstamp_get(struct dsa_switch *ds, int port,
+				struct ifreq *ifr)
+{
+	struct sja1105_private *priv = ds->priv;
+	struct hwtstamp_config config;
+
+	config.flags = 0;
+	if (priv->ports[port].hwts_tx_en)
+		config.tx_type = HWTSTAMP_TX_ON;
+	else
+		config.tx_type = HWTSTAMP_TX_OFF;
+	if (priv->tagger_data.hwts_rx_en)
+		config.rx_filter = HWTSTAMP_FILTER_PTP_V2_L2_EVENT;
+	else
+		config.rx_filter = HWTSTAMP_FILTER_NONE;
+
+	return copy_to_user(ifr->ifr_data, &config, sizeof(config)) ?
+		-EFAULT : 0;
+}
+
+#define to_tagger(d) \
+	container_of((d), struct sja1105_tagger_data, rxtstamp_work)
+#define to_sja1105(d) \
+	container_of((d), struct sja1105_private, tagger_data)
+
+static void sja1105_rxtstamp_work(struct work_struct *work)
+{
+	struct sja1105_tagger_data *data = to_tagger(work);
+	struct sja1105_private *priv = to_sja1105(data);
+	struct sk_buff *skb;
+	u64 now;
+
+	mutex_lock(&priv->ptp_lock);
+
+	now = priv->tstamp_cc.read(&priv->tstamp_cc);
+
+	while ((skb = skb_dequeue(&data->skb_rxtstamp_queue)) != NULL) {
+		struct skb_shared_hwtstamps *shwt = skb_hwtstamps(skb);
+		u64 ts;
+
+		*shwt = (struct skb_shared_hwtstamps) {0};
+
+		ts = SJA1105_SKB_CB(skb)->meta_tstamp;
+		ts = sja1105_tstamp_reconstruct(priv, now, ts);
+		ts = timecounter_cyc2time(&priv->tstamp_tc, ts);
+
+		shwt->hwtstamp = ns_to_ktime(ts);
+		netif_rx_ni(skb);
+	}
+
+	mutex_unlock(&priv->ptp_lock);
+}
+
+/* Called from dsa_skb_defer_rx_timestamp */
+bool sja1105_port_rxtstamp(struct dsa_switch *ds, int port,
+			   struct sk_buff *skb, unsigned int type)
+{
+	struct sja1105_private *priv = ds->priv;
+	struct sja1105_tagger_data *data = &priv->tagger_data;
+
+	if (!data->hwts_rx_en)
+		return false;
+
+	/* We need to read the full PTP clock to reconstruct the Rx
+	 * timestamp. For that we need a sleepable context.
+	 */
+	skb_queue_tail(&data->skb_rxtstamp_queue, skb);
+	schedule_work(&data->rxtstamp_work);
+	return true;
+}
+
+/* Called from dsa_skb_tx_timestamp. This callback is just to make DSA clone
+ * the skb and have it available in DSA_SKB_CB in the .port_deferred_xmit
+ * callback, where we will timestamp it synchronously.
+ */
+bool sja1105_port_txtstamp(struct dsa_switch *ds, int port,
+			   struct sk_buff *skb, unsigned int type)
+{
+	struct sja1105_private *priv = ds->priv;
+	struct sja1105_port *sp = &priv->ports[port];
+
+	if (!sp->hwts_tx_en)
+		return false;
+
+	return true;
+}
+
 static const struct dsa_switch_ops sja1105_switch_ops = {
 	.get_tag_protocol	= sja1105_get_tag_protocol,
 	.setup			= sja1105_setup,
+	.teardown		= sja1105_teardown,
 	.set_ageing_time	= sja1105_set_ageing_time,
 	.phylink_validate	= sja1105_phylink_validate,
 	.phylink_mac_config	= sja1105_mac_config,
 	.get_strings		= sja1105_get_strings,
 	.get_ethtool_stats	= sja1105_get_ethtool_stats,
 	.get_sset_count		= sja1105_get_sset_count,
+	.get_ts_info		= sja1105_get_ts_info,
 	.port_fdb_dump		= sja1105_fdb_dump,
 	.port_fdb_add		= sja1105_fdb_add,
 	.port_fdb_del		= sja1105_fdb_del,
@@ -1688,6 +1941,10 @@ static const struct dsa_switch_ops sja1105_switch_ops = {
 	.port_mdb_add		= sja1105_mdb_add,
 	.port_mdb_del		= sja1105_mdb_del,
 	.port_deferred_xmit	= sja1105_port_deferred_xmit,
+	.port_hwtstamp_get	= sja1105_hwtstamp_get,
+	.port_hwtstamp_set	= sja1105_hwtstamp_set,
+	.port_rxtstamp		= sja1105_port_rxtstamp,
+	.port_txtstamp		= sja1105_port_txtstamp,
 };
 
 static int sja1105_check_device_id(struct sja1105_private *priv)
@@ -1728,6 +1985,7 @@ static int sja1105_check_device_id(struct sja1105_private *priv)
 
 static int sja1105_probe(struct spi_device *spi)
 {
+	struct sja1105_tagger_data *tagger_data;
 	struct device *dev = &spi->dev;
 	struct sja1105_private *priv;
 	struct dsa_switch *ds;
@@ -1782,12 +2040,17 @@ static int sja1105_probe(struct spi_device *spi)
 	ds->priv = priv;
 	priv->ds = ds;
 
+	tagger_data = &priv->tagger_data;
+	skb_queue_head_init(&tagger_data->skb_rxtstamp_queue);
+	INIT_WORK(&tagger_data->rxtstamp_work, sja1105_rxtstamp_work);
+
 	/* Connections between dsa_port and sja1105_port */
 	for (i = 0; i < SJA1105_NUM_PORTS; i++) {
 		struct sja1105_port *sp = &priv->ports[i];
 
 		ds->ports[i].priv = sp;
 		sp->dp = &ds->ports[i];
+		sp->data = tagger_data;
 	}
 	mutex_init(&priv->mgmt_lock);
 
@@ -1798,6 +2061,7 @@ static int sja1105_remove(struct spi_device *spi)
 {
 	struct sja1105_private *priv = spi_get_drvdata(spi);
 
+	sja1105_ptp_clock_unregister(priv);
 	dsa_unregister_switch(priv->ds);
 	sja1105_static_config_free(&priv->static_config);
 	return 0;

drivers/net/dsa/sja1105/sja1105_ptp.c

+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2019, Vladimir Oltean <olteanv@gmail.com>
+ */
+#include "sja1105.h"
+
+/* The adjfine API clamps ppb between [-32,768,000, 32,768,000], and
+ * therefore scaled_ppm between [-2,147,483,648, 2,147,483,647].
+ * Set the maximum supported ppb to a round value smaller than the maximum.
+ *
+ * Percentually speaking, this is a +/- 0.032x adjustment of the
+ * free-running counter (0.968x to 1.032x).
+ */
+#define SJA1105_MAX_ADJ_PPB		32000000
+#define SJA1105_SIZE_PTP_CMD		4
+
+/* Timestamps are in units of 8 ns clock ticks (equivalent to a fixed
+ * 125 MHz clock) so the scale factor (MULT / SHIFT) needs to be 8.
+ * Furthermore, wisely pick SHIFT as 28 bits, which translates
+ * MULT into 2^31 (0x80000000).  This is the same value around which
+ * the hardware PTPCLKRATE is centered, so the same ppb conversion
+ * arithmetic can be reused.
+ */
+#define SJA1105_CC_SHIFT		28
+#define SJA1105_CC_MULT			(8 << SJA1105_CC_SHIFT)
+
+/* Having 33 bits of cycle counter left until a 64-bit overflow during delta
+ * conversion, we multiply this by the 8 ns counter resolution and arrive at
+ * a comfortable 68.71 second refresh interval until the delta would cause
+ * an integer overflow, in absence of any other readout.
+ * Approximate to 1 minute.
+ */
+#define SJA1105_REFRESH_INTERVAL	(HZ * 60)
+
+/*            This range is actually +/- SJA1105_MAX_ADJ_PPB
+ *            divided by 1000 (ppb -> ppm) and with a 16-bit
+ *            "fractional" part (actually fixed point).
+ *                                    |
+ *                                    v
+ * Convert scaled_ppm from the +/- ((10^6) << 16) range
+ * into the +/- (1 << 31) range.
+ *
+ * This forgoes a "ppb" numeric representation (up to NSEC_PER_SEC)
+ * and defines the scaling factor between scaled_ppm and the actual
+ * frequency adjustments (both cycle counter and hardware).
+ *
+ *   ptpclkrate = scaled_ppm * 2^31 / (10^6 * 2^16)
+ *   simplifies to
+ *   ptpclkrate = scaled_ppm * 2^9 / 5^6
+ */
+#define SJA1105_CC_MULT_NUM		(1 << 9)
+#define SJA1105_CC_MULT_DEM		15625
+
+#define ptp_to_sja1105(d) container_of((d), struct sja1105_private, ptp_caps)
+#define cc_to_sja1105(d) container_of((d), struct sja1105_private, tstamp_cc)
+#define dw_to_sja1105(d) container_of((d), struct sja1105_private, refresh_work)
+
+struct sja1105_ptp_cmd {
+	u64 resptp;       /* reset */
+};
+
+int sja1105_get_ts_info(struct dsa_switch *ds, int port,
+			struct ethtool_ts_info *info)
+{
+	struct sja1105_private *priv = ds->priv;
+
+	/* Called during cleanup */
+	if (!priv->clock)
+		return -ENODEV;
+
+	info->so_timestamping = SOF_TIMESTAMPING_TX_HARDWARE |
+				SOF_TIMESTAMPING_RX_HARDWARE |
+				SOF_TIMESTAMPING_RAW_HARDWARE;
+	info->tx_types = (1 << HWTSTAMP_TX_OFF) |
+			 (1 << HWTSTAMP_TX_ON);
+	info->rx_filters = (1 << HWTSTAMP_FILTER_NONE) |
+			   (1 << HWTSTAMP_FILTER_PTP_V2_L2_EVENT);
+	info->phc_index = ptp_clock_index(priv->clock);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(sja1105_get_ts_info);
+
+int sja1105et_ptp_cmd(const void *ctx, const void *data)
+{
+	const struct sja1105_ptp_cmd *cmd = data;
+	const struct sja1105_private *priv = ctx;
+	const struct sja1105_regs *regs = priv->info->regs;
+	const int size = SJA1105_SIZE_PTP_CMD;
+	u8 buf[SJA1105_SIZE_PTP_CMD] = {0};
+	/* No need to keep this as part of the structure */
+	u64 valid = 1;
+
+	sja1105_pack(buf, &valid,           31, 31, size);
+	sja1105_pack(buf, &cmd->resptp,      2,  2, size);
+
+	return sja1105_spi_send_packed_buf(priv, SPI_WRITE, regs->ptp_control,
+					   buf, SJA1105_SIZE_PTP_CMD);
+}
+EXPORT_SYMBOL_GPL(sja1105et_ptp_cmd);
+
+int sja1105pqrs_ptp_cmd(const void *ctx, const void *data)
+{
+	const struct sja1105_ptp_cmd *cmd = data;
+	const struct sja1105_private *priv = ctx;
+	const struct sja1105_regs *regs = priv->info->regs;
+	const int size = SJA1105_SIZE_PTP_CMD;
+	u8 buf[SJA1105_SIZE_PTP_CMD] = {0};
+	/* No need to keep this as part of the structure */
+	u64 valid = 1;
+
+	sja1105_pack(buf, &valid,           31, 31, size);
+	sja1105_pack(buf, &cmd->resptp,      3,  3, size);
+
+	return sja1105_spi_send_packed_buf(priv, SPI_WRITE, regs->ptp_control,
+					   buf, SJA1105_SIZE_PTP_CMD);
+}
+EXPORT_SYMBOL_GPL(sja1105pqrs_ptp_cmd);
+
+/* The switch returns partial timestamps (24 bits for SJA1105 E/T, which wrap
+ * around in 0.135 seconds, and 32 bits for P/Q/R/S, wrapping around in 34.35
+ * seconds).
+ *
+ * This receives the RX or TX MAC timestamps, provided by hardware as
+ * the lower bits of the cycle counter, sampled at the time the timestamp was
+ * collected.
+ *
+ * To reconstruct into a full 64-bit-wide timestamp, the cycle counter is
+ * read and the high-order bits are filled in.
+ *
+ * Must be called within one wraparound period of the partial timestamp since
+ * it was generated by the MAC.
+ */
+u64 sja1105_tstamp_reconstruct(struct sja1105_private *priv, u64 now,
+			       u64 ts_partial)
+{
+	u64 partial_tstamp_mask = CYCLECOUNTER_MASK(priv->info->ptp_ts_bits);
+	u64 ts_reconstructed;
+
+	ts_reconstructed = (now & ~partial_tstamp_mask) | ts_partial;
+
+	/* Check lower bits of current cycle counter against the timestamp.
+	 * If the current cycle counter is lower than the partial timestamp,
+	 * then wraparound surely occurred and must be accounted for.
+	 */
+	if ((now & partial_tstamp_mask) <= ts_partial)
+		ts_reconstructed -= (partial_tstamp_mask + 1);
+
+	return ts_reconstructed;
+}
+EXPORT_SYMBOL_GPL(sja1105_tstamp_reconstruct);
+
+/* Reads the SPI interface for an egress timestamp generated by the switch
+ * for frames sent using management routes.
+ *
+ * SJA1105 E/T layout of the 4-byte SPI payload:
+ *
+ * 31    23    15    7     0
+ * |     |     |     |     |
+ * +-----+-----+-----+     ^
+ *          ^              |
+ *          |              |
+ *  24-bit timestamp   Update bit
+ *
+ *
+ * SJA1105 P/Q/R/S layout of the 8-byte SPI payload:
+ *
+ * 31    23    15    7     0     63    55    47    39    32
+ * |     |     |     |     |     |     |     |     |     |
+ *                         ^     +-----+-----+-----+-----+
+ *                         |                 ^
+ *                         |                 |
+ *                    Update bit    32-bit timestamp
+ *
+ * Notice that the update bit is in the same place.
+ * To have common code for E/T and P/Q/R/S for reading the timestamp,
+ * we need to juggle with the offset and the bit indices.
+ */
+int sja1105_ptpegr_ts_poll(struct sja1105_private *priv, int port, u64 *ts)
+{
+	const struct sja1105_regs *regs = priv->info->regs;
+	int tstamp_bit_start, tstamp_bit_end;
+	int timeout = 10;
+	u8 packed_buf[8];
+	u64 update;
+	int rc;
+
+	do {
+		rc = sja1105_spi_send_packed_buf(priv, SPI_READ,
+						 regs->ptpegr_ts[port],
+						 packed_buf,
+						 priv->info->ptpegr_ts_bytes);
+		if (rc < 0)
+			return rc;
+
+		sja1105_unpack(packed_buf, &update, 0, 0,
+			       priv->info->ptpegr_ts_bytes);
+		if (update)
+			break;
+
+		usleep_range(10, 50);
+	} while (--timeout);
+
+	if (!timeout)
+		return -ETIMEDOUT;
+
+	/* Point the end bit to the second 32-bit word on P/Q/R/S,
+	 * no-op on E/T.
+	 */
+	tstamp_bit_end = (priv->info->ptpegr_ts_bytes - 4) * 8;
+	/* Shift the 24-bit timestamp on E/T to be collected from 31:8.
+	 * No-op on P/Q/R/S.
+	 */
+	tstamp_bit_end += 32 - priv->info->ptp_ts_bits;
+	tstamp_bit_start = tstamp_bit_end + priv->info->ptp_ts_bits - 1;
+
+	*ts = 0;
+
+	sja1105_unpack(packed_buf, ts, tstamp_bit_start, tstamp_bit_end,
+		       priv->info->ptpegr_ts_bytes);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(sja1105_ptpegr_ts_poll);
+
+int sja1105_ptp_reset(struct sja1105_private *priv)
+{
+	struct dsa_switch *ds = priv->ds;
+	struct sja1105_ptp_cmd cmd = {0};
+	int rc;
+
+	mutex_lock(&priv->ptp_lock);
+
+	cmd.resptp = 1;
+	dev_dbg(ds->dev, "Resetting PTP clock\n");
+	rc = priv->info->ptp_cmd(priv, &cmd);
+
+	timecounter_init(&priv->tstamp_tc, &priv->tstamp_cc,
+			 ktime_to_ns(ktime_get_real()));
+
+	mutex_unlock(&priv->ptp_lock);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(sja1105_ptp_reset);
+
+static int sja1105_ptp_gettime(struct ptp_clock_info *ptp,
+			       struct timespec64 *ts)
+{
+	struct sja1105_private *priv = ptp_to_sja1105(ptp);
+	u64 ns;
+
+	mutex_lock(&priv->ptp_lock);
+	ns = timecounter_read(&priv->tstamp_tc);
+	mutex_unlock(&priv->ptp_lock);
+
+	*ts = ns_to_timespec64(ns);
+
+	return 0;
+}
+
+static int sja1105_ptp_settime(struct ptp_clock_info *ptp,
+			       const struct timespec64 *ts)
+{
+	struct sja1105_private *priv = ptp_to_sja1105(ptp);
+	u64 ns = timespec64_to_ns(ts);
+
+	mutex_lock(&priv->ptp_lock);
+	timecounter_init(&priv->tstamp_tc, &priv->tstamp_cc, ns);
+	mutex_unlock(&priv->ptp_lock);
+
+	return 0;
+}
+
+static int sja1105_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
+{
+	struct sja1105_private *priv = ptp_to_sja1105(ptp);
+	s64 clkrate;
+
+	clkrate = (s64)scaled_ppm * SJA1105_CC_MULT_NUM;
+	clkrate = div_s64(clkrate, SJA1105_CC_MULT_DEM);
+
+	mutex_lock(&priv->ptp_lock);
+
+	/* Force a readout to update the timer *before* changing its frequency.
+	 *
+	 * This way, its corrected time curve can at all times be modeled
+	 * as a linear "A * x + B" function, where:
+	 *
+	 * - B are past frequency adjustments and offset shifts, all
+	 *   accumulated into the cycle_last variable.
+	 *
+	 * - A is the new frequency adjustments we're just about to set.
+	 *
+	 * Reading now makes B accumulate the correct amount of time,
+	 * corrected at the old rate, before changing it.
+	 *
+	 * Hardware timestamps then become simple points on the curve and
+	 * are approximated using the above function.  This is still better
+	 * than letting the switch take the timestamps using the hardware
+	 * rate-corrected clock (PTPCLKVAL) - the comparison in this case would
+	 * be that we're shifting the ruler at the same time as we're taking
+	 * measurements with it.
+	 *
+	 * The disadvantage is that it's possible to receive timestamps when
+	 * a frequency adjustment took place in the near past.
+	 * In this case they will be approximated using the new ppb value
+	 * instead of a compound function made of two segments (one at the old
+	 * and the other at the new rate) - introducing some inaccuracy.
+	 */
+	timecounter_read(&priv->tstamp_tc);
+
+	priv->tstamp_cc.mult = SJA1105_CC_MULT + clkrate;
+
+	mutex_unlock(&priv->ptp_lock);
+
+	return 0;
+}
+
+static int sja1105_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
+{
+	struct sja1105_private *priv = ptp_to_sja1105(ptp);
+
+	mutex_lock(&priv->ptp_lock);
+	timecounter_adjtime(&priv->tstamp_tc, delta);
+	mutex_unlock(&priv->ptp_lock);
+
+	return 0;
+}
+
+static u64 sja1105_ptptsclk_read(const struct cyclecounter *cc)
+{
+	struct sja1105_private *priv = cc_to_sja1105(cc);
+	const struct sja1105_regs *regs = priv->info->regs;
+	u64 ptptsclk = 0;
+	int rc;
+
+	rc = sja1105_spi_send_int(priv, SPI_READ, regs->ptptsclk,
+				  &ptptsclk, 8);
+	if (rc < 0)
+		dev_err_ratelimited(priv->ds->dev,
+				    "failed to read ptp cycle counter: %d\n",
+				    rc);
+	return ptptsclk;
+}
+
+static void sja1105_ptp_overflow_check(struct work_struct *work)
+{
+	struct delayed_work *dw = to_delayed_work(work);
+	struct sja1105_private *priv = dw_to_sja1105(dw);
+	struct timespec64 ts;
+
+	sja1105_ptp_gettime(&priv->ptp_caps, &ts);
+
+	schedule_delayed_work(&priv->refresh_work, SJA1105_REFRESH_INTERVAL);
+}
+
+static const struct ptp_clock_info sja1105_ptp_caps = {
+	.owner		= THIS_MODULE,
+	.name		= "SJA1105 PHC",
+	.adjfine	= sja1105_ptp_adjfine,
+	.adjtime	= sja1105_ptp_adjtime,
+	.gettime64	= sja1105_ptp_gettime,
+	.settime64	= sja1105_ptp_settime,
+	.max_adj	= SJA1105_MAX_ADJ_PPB,
+};
+
+int sja1105_ptp_clock_register(struct sja1105_private *priv)
+{
+	struct dsa_switch *ds = priv->ds;
+
+	/* Set up the cycle counter */
+	priv->tstamp_cc = (struct cyclecounter) {
+		.read = sja1105_ptptsclk_read,
+		.mask = CYCLECOUNTER_MASK(64),
+		.shift = SJA1105_CC_SHIFT,
+		.mult = SJA1105_CC_MULT,
+	};
+	mutex_init(&priv->ptp_lock);
+	INIT_DELAYED_WORK(&priv->refresh_work, sja1105_ptp_overflow_check);
+
+	schedule_delayed_work(&priv->refresh_work, SJA1105_REFRESH_INTERVAL);
+
+	priv->ptp_caps = sja1105_ptp_caps;
+
+	priv->clock = ptp_clock_register(&priv->ptp_caps, ds->dev);
+	if (IS_ERR_OR_NULL(priv->clock))
+		return PTR_ERR(priv->clock);
+
+	return sja1105_ptp_reset(priv);
+}
+EXPORT_SYMBOL_GPL(sja1105_ptp_clock_register);
+
+void sja1105_ptp_clock_unregister(struct sja1105_private *priv)
+{
+	if (IS_ERR_OR_NULL(priv->clock))
+		return;
+
+	ptp_clock_unregister(priv->clock);
+	priv->clock = NULL;
+}
+EXPORT_SYMBOL_GPL(sja1105_ptp_clock_unregister);
+
+MODULE_AUTHOR("Vladimir Oltean <olteanv@gmail.com>");
+MODULE_DESCRIPTION("SJA1105 PHC Driver");
+MODULE_LICENSE("GPL v2");

drivers/net/dsa/sja1105/sja1105_ptp.h

+/* SPDX-License-Identifier: GPL-2.0
+ * Copyright (c) 2019, Vladimir Oltean <olteanv@gmail.com>
+ */
+#ifndef _SJA1105_PTP_H
+#define _SJA1105_PTP_H
+
+#if IS_ENABLED(CONFIG_NET_DSA_SJA1105_PTP)
+
+int sja1105_ptp_clock_register(struct sja1105_private *priv);
+
+void sja1105_ptp_clock_unregister(struct sja1105_private *priv);
+
+int sja1105_ptpegr_ts_poll(struct sja1105_private *priv, int port, u64 *ts);
+
+int sja1105et_ptp_cmd(const void *ctx, const void *data);
+
+int sja1105pqrs_ptp_cmd(const void *ctx, const void *data);
+
+int sja1105_get_ts_info(struct dsa_switch *ds, int port,
+			struct ethtool_ts_info *ts);
+
+u64 sja1105_tstamp_reconstruct(struct sja1105_private *priv, u64 now,
+			       u64 ts_partial);
+
+int sja1105_ptp_reset(struct sja1105_private *priv);
+
+#else
+
+static inline int sja1105_ptp_clock_register(struct sja1105_private *priv)
+{
+	return 0;
+}
+
+static inline void sja1105_ptp_clock_unregister(struct sja1105_private *priv)
+{
+	return;
+}
+
+static inline int
+sja1105_ptpegr_ts_poll(struct sja1105_private *priv, int port, u64 *ts)
+{
+	return 0;
+}
+
+static inline u64 sja1105_tstamp_reconstruct(struct sja1105_private *priv,
+					     u64 now, u64 ts_partial)
+{
+	return 0;
+}
+
+static inline int sja1105_ptp_reset(struct sja1105_private *priv)
+{
+	return 0;
+}
+
+#define sja1105et_ptp_cmd NULL
+
+#define sja1105pqrs_ptp_cmd NULL
+
+#define sja1105_get_ts_info NULL
+
+#endif /* IS_ENABLED(CONFIG_NET_DSA_SJA1105_PTP) */
+
+#endif /* _SJA1105_PTP_H */

drivers/net/dsa/sja1105/sja1105_spi.c

@@ -100,6 +100,7 @@ int sja1105_spi_send_packed_buf(const struct sja1105_private *priv,
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(sja1105_spi_send_packed_buf);
 
 /* If @rw is:
  * - SPI_WRITE: creates and sends an SPI write message at absolute
@@ -135,6 +136,7 @@ int sja1105_spi_send_int(const struct sja1105_private *priv,
 
 	return rc;
 }
+EXPORT_SYMBOL_GPL(sja1105_spi_send_int);
 
 /* Should be used if a @packed_buf larger than SJA1105_SIZE_SPI_MSG_MAXLEN
  * must be sent/received. Splitting the buffer into chunks and assembling
@@ -478,7 +480,12 @@ int sja1105_static_config_upload(struct sja1105_private *priv)
 		dev_info(dev, "Succeeded after %d tried\n", RETRIES - retries);
 	}
 
+	rc = sja1105_ptp_reset(priv);
+	if (rc < 0)
+		dev_err(dev, "Failed to reset PTP clock: %d\n", rc);
+
 	dev_info(dev, "Reset switch and programmed static config\n");
+
 out:
 	kfree(config_buf);
 	return rc;
@@ -507,6 +514,11 @@ static struct sja1105_regs sja1105et_regs = {
 	.rgmii_tx_clk = {0x100016, 0x10001D, 0x100024, 0x10002B, 0x100032},
 	.rmii_ref_clk = {0x100015, 0x10001C, 0x100023, 0x10002A, 0x100031},
 	.rmii_ext_tx_clk = {0x100018, 0x10001F, 0x100026, 0x10002D, 0x100034},
+	.ptpegr_ts = {0xC0, 0xC2, 0xC4, 0xC6, 0xC8},
+	.ptp_control = 0x17,
+	.ptpclk = 0x18, /* Spans 0x18 to 0x19 */
+	.ptpclkrate = 0x1A,
+	.ptptsclk = 0x1B, /* Spans 0x1B to 0x1C */
 };
 
 static struct sja1105_regs sja1105pqrs_regs = {
@@ -533,6 +545,11 @@ static struct sja1105_regs sja1105pqrs_regs = {
 	.rmii_ref_clk = {0x100015, 0x10001B, 0x100021, 0x100027, 0x10002D},
 	.rmii_ext_tx_clk = {0x100017, 0x10001D, 0x100023, 0x100029, 0x10002F},
 	.qlevel = {0x604, 0x614, 0x624, 0x634, 0x644},
+	.ptpegr_ts = {0xC0, 0xC4, 0xC8, 0xCC, 0xD0},
+	.ptp_control = 0x18,
+	.ptpclk = 0x19,
+	.ptpclkrate = 0x1B,
+	.ptptsclk = 0x1C,
 };
 
 struct sja1105_info sja1105e_info = {
@@ -540,9 +557,12 @@ struct sja1105_info sja1105e_info = {
 	.part_no		= SJA1105ET_PART_NO,
 	.static_ops		= sja1105e_table_ops,
 	.dyn_ops		= sja1105et_dyn_ops,
+	.ptp_ts_bits		= 24,
+	.ptpegr_ts_bytes	= 4,
 	.reset_cmd		= sja1105et_reset_cmd,
 	.fdb_add_cmd		= sja1105et_fdb_add,
 	.fdb_del_cmd		= sja1105et_fdb_del,
+	.ptp_cmd		= sja1105et_ptp_cmd,
 	.regs			= &sja1105et_regs,
 	.name			= "SJA1105E",
 };
@@ -551,9 +571,12 @@ struct sja1105_info sja1105t_info = {
 	.part_no		= SJA1105ET_PART_NO,
 	.static_ops		= sja1105t_table_ops,
 	.dyn_ops		= sja1105et_dyn_ops,
+	.ptp_ts_bits		= 24,
+	.ptpegr_ts_bytes	= 4,
 	.reset_cmd		= sja1105et_reset_cmd,
 	.fdb_add_cmd		= sja1105et_fdb_add,
 	.fdb_del_cmd		= sja1105et_fdb_del,
+	.ptp_cmd		= sja1105et_ptp_cmd,
 	.regs			= &sja1105et_regs,
 	.name			= "SJA1105T",
 };
@@ -562,9 +585,12 @@ struct sja1105_info sja1105p_info = {
 	.part_no		= SJA1105P_PART_NO,
 	.static_ops		= sja1105p_table_ops,
 	.dyn_ops		= sja1105pqrs_dyn_ops,
+	.ptp_ts_bits		= 32,
+	.ptpegr_ts_bytes	= 8,
 	.reset_cmd		= sja1105pqrs_reset_cmd,
 	.fdb_add_cmd		= sja1105pqrs_fdb_add,
 	.fdb_del_cmd		= sja1105pqrs_fdb_del,
+	.ptp_cmd		= sja1105pqrs_ptp_cmd,
 	.regs			= &sja1105pqrs_regs,
 	.name			= "SJA1105P",
 };
@@ -573,9 +599,12 @@ struct sja1105_info sja1105q_info = {
 	.part_no		= SJA1105Q_PART_NO,
 	.static_ops		= sja1105q_table_ops,
 	.dyn_ops		= sja1105pqrs_dyn_ops,
+	.ptp_ts_bits		= 32,
+	.ptpegr_ts_bytes	= 8,
 	.reset_cmd		= sja1105pqrs_reset_cmd,
 	.fdb_add_cmd		= sja1105pqrs_fdb_add,
 	.fdb_del_cmd		= sja1105pqrs_fdb_del,
+	.ptp_cmd		= sja1105pqrs_ptp_cmd,
 	.regs			= &sja1105pqrs_regs,
 	.name			= "SJA1105Q",
 };
@@ -584,9 +613,12 @@ struct sja1105_info sja1105r_info = {
 	.part_no		= SJA1105R_PART_NO,
 	.static_ops		= sja1105r_table_ops,
 	.dyn_ops		= sja1105pqrs_dyn_ops,
+	.ptp_ts_bits		= 32,
+	.ptpegr_ts_bytes	= 8,
 	.reset_cmd		= sja1105pqrs_reset_cmd,
 	.fdb_add_cmd		= sja1105pqrs_fdb_add,
 	.fdb_del_cmd		= sja1105pqrs_fdb_del,
+	.ptp_cmd		= sja1105pqrs_ptp_cmd,
 	.regs			= &sja1105pqrs_regs,
 	.name			= "SJA1105R",
 };
@@ -596,8 +628,11 @@ struct sja1105_info sja1105s_info = {
 	.static_ops		= sja1105s_table_ops,
 	.dyn_ops		= sja1105pqrs_dyn_ops,
 	.regs			= &sja1105pqrs_regs,
+	.ptp_ts_bits		= 32,
+	.ptpegr_ts_bytes	= 8,
 	.reset_cmd		= sja1105pqrs_reset_cmd,
 	.fdb_add_cmd		= sja1105pqrs_fdb_add,
 	.fdb_del_cmd		= sja1105pqrs_fdb_del,
+	.ptp_cmd		= sja1105pqrs_ptp_cmd,
 	.name			= "SJA1105S",
 };

drivers/net/dsa/sja1105/sja1105_static_config.c

@@ -35,6 +35,7 @@ void sja1105_pack(void *buf, const u64 *val, int start, int end, size_t len)
 	}
 	dump_stack();
 }
+EXPORT_SYMBOL_GPL(sja1105_pack);
 
 void sja1105_unpack(const void *buf, u64 *val, int start, int end, size_t len)
 {
@@ -52,6 +53,7 @@ void sja1105_unpack(const void *buf, u64 *val, int start, int end, size_t len)
 		       start, end);
 	dump_stack();
 }
+EXPORT_SYMBOL_GPL(sja1105_unpack);
 
 void sja1105_packing(void *buf, u64 *val, int start, int end,
 		     size_t len, enum packing_op op)
@@ -74,6 +76,7 @@ void sja1105_packing(void *buf, u64 *val, int start, int end,
 	}
 	dump_stack();
 }
+EXPORT_SYMBOL_GPL(sja1105_packing);
 
 /* Little-endian Ethernet CRC32 of data packed as big-endian u32 words */
 u32 sja1105_crc32(const void *buf, size_t len)
@@ -91,6 +94,28 @@ u32 sja1105_crc32(const void *buf, size_t len)
 	return ~crc;
 }
 
+static size_t sja1105et_avb_params_entry_packing(void *buf, void *entry_ptr,
+						 enum packing_op op)
+{
+	const size_t size = SJA1105ET_SIZE_AVB_PARAMS_ENTRY;
+	struct sja1105_avb_params_entry *entry = entry_ptr;
+
+	sja1105_packing(buf, &entry->destmeta, 95, 48, size, op);
+	sja1105_packing(buf, &entry->srcmeta,  47,  0, size, op);
+	return size;
+}
+
+static size_t sja1105pqrs_avb_params_entry_packing(void *buf, void *entry_ptr,
+						   enum packing_op op)
+{
+	const size_t size = SJA1105PQRS_SIZE_AVB_PARAMS_ENTRY;
+	struct sja1105_avb_params_entry *entry = entry_ptr;
+
+	sja1105_packing(buf, &entry->destmeta,   125,  78, size, op);
+	sja1105_packing(buf, &entry->srcmeta,     77,  30, size, op);
+	return size;
+}
+
 static size_t sja1105et_general_params_entry_packing(void *buf, void *entry_ptr,
 						     enum packing_op op)
 {
@@ -423,6 +448,7 @@ static u64 blk_id_map[BLK_IDX_MAX] = {
 	[BLK_IDX_MAC_CONFIG] = BLKID_MAC_CONFIG,
 	[BLK_IDX_L2_LOOKUP_PARAMS] = BLKID_L2_LOOKUP_PARAMS,
 	[BLK_IDX_L2_FORWARDING_PARAMS] = BLKID_L2_FORWARDING_PARAMS,
+	[BLK_IDX_AVB_PARAMS] = BLKID_AVB_PARAMS,
 	[BLK_IDX_GENERAL_PARAMS] = BLKID_GENERAL_PARAMS,
 	[BLK_IDX_XMII_PARAMS] = BLKID_XMII_PARAMS,
 };
@@ -624,6 +650,12 @@ struct sja1105_table_ops sja1105e_table_ops[BLK_IDX_MAX] = {
 		.packed_entry_size = SJA1105_SIZE_L2_FORWARDING_PARAMS_ENTRY,
 		.max_entry_count = SJA1105_MAX_L2_FORWARDING_PARAMS_COUNT,
 	},
+	[BLK_IDX_AVB_PARAMS] = {
+		.packing = sja1105et_avb_params_entry_packing,
+		.unpacked_entry_size = sizeof(struct sja1105_avb_params_entry),
+		.packed_entry_size = SJA1105ET_SIZE_AVB_PARAMS_ENTRY,
+		.max_entry_count = SJA1105_MAX_AVB_PARAMS_COUNT,
+	},
 	[BLK_IDX_GENERAL_PARAMS] = {
 		.packing = sja1105et_general_params_entry_packing,
 		.unpacked_entry_size = sizeof(struct sja1105_general_params_entry),
@@ -682,6 +714,12 @@ struct sja1105_table_ops sja1105t_table_ops[BLK_IDX_MAX] = {
 		.packed_entry_size = SJA1105_SIZE_L2_FORWARDING_PARAMS_ENTRY,
 		.max_entry_count = SJA1105_MAX_L2_FORWARDING_PARAMS_COUNT,
 	},
+	[BLK_IDX_AVB_PARAMS] = {
+		.packing = sja1105et_avb_params_entry_packing,
+		.unpacked_entry_size = sizeof(struct sja1105_avb_params_entry),
+		.packed_entry_size = SJA1105ET_SIZE_AVB_PARAMS_ENTRY,
+		.max_entry_count = SJA1105_MAX_AVB_PARAMS_COUNT,
+	},
 	[BLK_IDX_GENERAL_PARAMS] = {
 		.packing = sja1105et_general_params_entry_packing,
 		.unpacked_entry_size = sizeof(struct sja1105_general_params_entry),
@@ -740,6 +778,12 @@ struct sja1105_table_ops sja1105p_table_ops[BLK_IDX_MAX] = {
 		.packed_entry_size = SJA1105_SIZE_L2_FORWARDING_PARAMS_ENTRY,
 		.max_entry_count = SJA1105_MAX_L2_FORWARDING_PARAMS_COUNT,
 	},
+	[BLK_IDX_AVB_PARAMS] = {
+		.packing = sja1105pqrs_avb_params_entry_packing,
+		.unpacked_entry_size = sizeof(struct sja1105_avb_params_entry),
+		.packed_entry_size = SJA1105PQRS_SIZE_AVB_PARAMS_ENTRY,
+		.max_entry_count = SJA1105_MAX_AVB_PARAMS_COUNT,
+	},
 	[BLK_IDX_GENERAL_PARAMS] = {
 		.packing = sja1105pqrs_general_params_entry_packing,
 		.unpacked_entry_size = sizeof(struct sja1105_general_params_entry),
@@ -798,6 +842,12 @@ struct sja1105_table_ops sja1105q_table_ops[BLK_IDX_MAX] = {
 		.packed_entry_size = SJA1105_SIZE_L2_FORWARDING_PARAMS_ENTRY,
 		.max_entry_count = SJA1105_MAX_L2_FORWARDING_PARAMS_COUNT,
 	},
+	[BLK_IDX_AVB_PARAMS] = {
+		.packing = sja1105pqrs_avb_params_entry_packing,
+		.unpacked_entry_size = sizeof(struct sja1105_avb_params_entry),
+		.packed_entry_size = SJA1105PQRS_SIZE_AVB_PARAMS_ENTRY,
+		.max_entry_count = SJA1105_MAX_AVB_PARAMS_COUNT,
+	},
 	[BLK_IDX_GENERAL_PARAMS] = {
 		.packing = sja1105pqrs_general_params_entry_packing,
 		.unpacked_entry_size = sizeof(struct sja1105_general_params_entry),
@@ -856,6 +906,12 @@ struct sja1105_table_ops sja1105r_table_ops[BLK_IDX_MAX] = {
 		.packed_entry_size = SJA1105_SIZE_L2_FORWARDING_PARAMS_ENTRY,
 		.max_entry_count = SJA1105_MAX_L2_FORWARDING_PARAMS_COUNT,
 	},
+	[BLK_IDX_AVB_PARAMS] = {
+		.packing = sja1105pqrs_avb_params_entry_packing,
+		.unpacked_entry_size = sizeof(struct sja1105_avb_params_entry),
+		.packed_entry_size = SJA1105PQRS_SIZE_AVB_PARAMS_ENTRY,
+		.max_entry_count = SJA1105_MAX_AVB_PARAMS_COUNT,
+	},
 	[BLK_IDX_GENERAL_PARAMS] = {
 		.packing = sja1105pqrs_general_params_entry_packing,
 		.unpacked_entry_size = sizeof(struct sja1105_general_params_entry),
@@ -914,6 +970,12 @@ struct sja1105_table_ops sja1105s_table_ops[BLK_IDX_MAX] = {
 		.packed_entry_size = SJA1105_SIZE_L2_FORWARDING_PARAMS_ENTRY,
 		.max_entry_count = SJA1105_MAX_L2_FORWARDING_PARAMS_COUNT,
 	},
+	[BLK_IDX_AVB_PARAMS] = {
+		.packing = sja1105pqrs_avb_params_entry_packing,
+		.unpacked_entry_size = sizeof(struct sja1105_avb_params_entry),
+		.packed_entry_size = SJA1105PQRS_SIZE_AVB_PARAMS_ENTRY,
+		.max_entry_count = SJA1105_MAX_AVB_PARAMS_COUNT,
+	},
 	[BLK_IDX_GENERAL_PARAMS] = {
 		.packing = sja1105pqrs_general_params_entry_packing,
 		.unpacked_entry_size = sizeof(struct sja1105_general_params_entry),

drivers/net/dsa/sja1105/sja1105_static_config.h

@@ -20,10 +20,12 @@
 #define SJA1105ET_SIZE_MAC_CONFIG_ENTRY			28
 #define SJA1105ET_SIZE_L2_LOOKUP_PARAMS_ENTRY		4
 #define SJA1105ET_SIZE_GENERAL_PARAMS_ENTRY		40
+#define SJA1105ET_SIZE_AVB_PARAMS_ENTRY			12
 #define SJA1105PQRS_SIZE_L2_LOOKUP_ENTRY		20
 #define SJA1105PQRS_SIZE_MAC_CONFIG_ENTRY		32
 #define SJA1105PQRS_SIZE_L2_LOOKUP_PARAMS_ENTRY		16
 #define SJA1105PQRS_SIZE_GENERAL_PARAMS_ENTRY		44
+#define SJA1105PQRS_SIZE_AVB_PARAMS_ENTRY		16
 
 /* UM10944.pdf Page 11, Table 2. Configuration Blocks */
 enum {
@@ -34,6 +36,7 @@ enum {
 	BLKID_MAC_CONFIG				= 0x09,
 	BLKID_L2_LOOKUP_PARAMS				= 0x0D,
 	BLKID_L2_FORWARDING_PARAMS			= 0x0E,
+	BLKID_AVB_PARAMS				= 0x10,
 	BLKID_GENERAL_PARAMS				= 0x11,
 	BLKID_XMII_PARAMS				= 0x4E,
 };
@@ -46,6 +49,7 @@ enum sja1105_blk_idx {
 	BLK_IDX_MAC_CONFIG,
 	BLK_IDX_L2_LOOKUP_PARAMS,
 	BLK_IDX_L2_FORWARDING_PARAMS,
+	BLK_IDX_AVB_PARAMS,
 	BLK_IDX_GENERAL_PARAMS,
 	BLK_IDX_XMII_PARAMS,
 	BLK_IDX_MAX,
@@ -64,6 +68,7 @@ enum sja1105_blk_idx {
 #define SJA1105_MAX_L2_FORWARDING_PARAMS_COUNT		1
 #define SJA1105_MAX_GENERAL_PARAMS_COUNT		1
 #define SJA1105_MAX_XMII_PARAMS_COUNT			1
+#define SJA1105_MAX_AVB_PARAMS_COUNT			1
 
 #define SJA1105_MAX_FRAME_MEMORY			929
 
@@ -179,6 +184,11 @@ struct sja1105_l2_policing_entry {
 	u64 partition;
 };
 
+struct sja1105_avb_params_entry {
+	u64 destmeta;
+	u64 srcmeta;
+};
+
 struct sja1105_mac_config_entry {
 	u64 top[8];
 	u64 base[8];

include/linux/dsa/8021q.h

@@ -20,9 +20,6 @@ int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int index,
 struct sk_buff *dsa_8021q_xmit(struct sk_buff *skb, struct net_device *netdev,
 			       u16 tpid, u16 tci);
 
-struct sk_buff *dsa_8021q_rcv(struct sk_buff *skb, struct net_device *netdev,
-			      struct packet_type *pt, u16 *tpid, u16 *tci);
-
 u16 dsa_8021q_tx_vid(struct dsa_switch *ds, int port);
 
 u16 dsa_8021q_rx_vid(struct dsa_switch *ds, int port);
@@ -31,6 +28,8 @@ int dsa_8021q_rx_switch_id(u16 vid);
 
 int dsa_8021q_rx_source_port(u16 vid);
 
+struct sk_buff *dsa_8021q_remove_header(struct sk_buff *skb);
+
 #else
 
 int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int index,
@@ -45,12 +44,6 @@ struct sk_buff *dsa_8021q_xmit(struct sk_buff *skb, struct net_device *netdev,
 	return NULL;
 }
 
-struct sk_buff *dsa_8021q_rcv(struct sk_buff *skb, struct net_device *netdev,
-			      struct packet_type *pt, u16 *tpid, u16 *tci)
-{
-	return NULL;
-}
-
 u16 dsa_8021q_tx_vid(struct dsa_switch *ds, int port)
 {
 	return 0;
@@ -71,6 +64,11 @@ int dsa_8021q_rx_source_port(u16 vid)
 	return 0;
 }
 
+struct sk_buff *dsa_8021q_remove_header(struct sk_buff *skb)
+{
+	return NULL;
+}
+
 #endif /* IS_ENABLED(CONFIG_NET_DSA_TAG_8021Q) */
 
 #endif /* _NET_DSA_8021Q_H */

include/linux/dsa/sja1105.h

@@ -12,6 +12,7 @@
 #include <net/dsa.h>
 
 #define ETH_P_SJA1105				ETH_P_DSA_8021Q
+#define ETH_P_SJA1105_META			0x0008
 
 /* IEEE 802.3 Annex 57A: Slow Protocols PDUs (01:80:C2:xx:xx:xx) */
 #define SJA1105_LINKLOCAL_FILTER_A		0x0180C2000000ull
@@ -20,8 +21,41 @@
 #define SJA1105_LINKLOCAL_FILTER_B		0x011B19000000ull
 #define SJA1105_LINKLOCAL_FILTER_B_MASK		0xFFFFFF000000ull
 
+/* Source and Destination MAC of follow-up meta frames.
+ * Whereas the choice of SMAC only affects the unique identification of the
+ * switch as sender of meta frames, the DMAC must be an address that is present
+ * in the DSA master port's multicast MAC filter.
+ * 01-80-C2-00-00-0E is a good choice for this, as all profiles of IEEE 1588
+ * over L2 use this address for some purpose already.
+ */
+#define SJA1105_META_SMAC			0x222222222222ull
+#define SJA1105_META_DMAC			0x0180C200000Eull
+
+/* Global tagger data: each struct sja1105_port has a reference to
+ * the structure defined in struct sja1105_private.
+ */
+struct sja1105_tagger_data {
+	struct sk_buff_head skb_rxtstamp_queue;
+	struct work_struct rxtstamp_work;
+	struct sk_buff *stampable_skb;
+	/* Protects concurrent access to the meta state machine
+	 * from taggers running on multiple ports on SMP systems
+	 */
+	spinlock_t meta_lock;
+	bool hwts_rx_en;
+};
+
+struct sja1105_skb_cb {
+	u32 meta_tstamp;
+};
+
+#define SJA1105_SKB_CB(skb) \
+	((struct sja1105_skb_cb *)DSA_SKB_CB_PRIV(skb))
+
 struct sja1105_port {
+	struct sja1105_tagger_data *data;
 	struct dsa_port *dp;
+	bool hwts_tx_en;
 	int mgmt_slot;
 };
 

include/net/dsa.h

@@ -357,6 +357,7 @@ struct dsa_switch_ops {
 						  int port);
 
 	int	(*setup)(struct dsa_switch *ds);
+	void	(*teardown)(struct dsa_switch *ds);
 	u32	(*get_phy_flags)(struct dsa_switch *ds, int port);
 
 	/*

net/dsa/dsa2.c

@@ -408,6 +408,9 @@ static void dsa_switch_teardown(struct dsa_switch *ds)
 
 	dsa_switch_unregister_notifier(ds);
 
+	if (ds->ops->teardown)
+		ds->ops->teardown(ds);
+
 	if (ds->devlink) {
 		devlink_unregister(ds->devlink);
 		devlink_free(ds->devlink);

net/dsa/slave.c

@@ -423,6 +423,8 @@ static void dsa_skb_tx_timestamp(struct dsa_slave_priv *p,
 	if (!clone)
 		return;
 
+	DSA_SKB_CB(skb)->clone = clone;
+
 	if (ds->ops->port_txtstamp(ds, p->dp->index, clone, type))
 		return;
 
@@ -460,6 +462,7 @@ static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev)
 	u64_stats_update_end(&s->syncp);
 
 	DSA_SKB_CB(skb)->deferred_xmit = false;
+	DSA_SKB_CB(skb)->clone = NULL;
 
 	/* Identify PTP protocol packets, clone them, and pass them to the
 	 * switch driver

net/dsa/tag_8021q.c

@@ -235,31 +235,48 @@ struct sk_buff *dsa_8021q_xmit(struct sk_buff *skb, struct net_device *netdev,
 }
 EXPORT_SYMBOL_GPL(dsa_8021q_xmit);
 
-struct sk_buff *dsa_8021q_rcv(struct sk_buff *skb, struct net_device *netdev,
-			      struct packet_type *pt, u16 *tpid, u16 *tci)
-{
-	struct vlan_ethhdr *tag;
-
-	if (unlikely(!pskb_may_pull(skb, VLAN_HLEN)))
-		return NULL;
-
-	tag = vlan_eth_hdr(skb);
-	*tpid = ntohs(tag->h_vlan_proto);
-	*tci = ntohs(tag->h_vlan_TCI);
-
-	/* skb->data points in the middle of the VLAN tag,
-	 * after tpid and before tci. This is because so far,
-	 * ETH_HLEN (DMAC, SMAC, EtherType) bytes were pulled.
+/* In the DSA packet_type handler, skb->data points in the middle of the VLAN
+ * tag, after tpid and before tci. This is because so far, ETH_HLEN
+ * (DMAC, SMAC, EtherType) bytes were pulled.
  * There are 2 bytes of VLAN tag left in skb->data, and upper
  * layers expect the 'real' EtherType to be consumed as well.
  * Coincidentally, a VLAN header is also of the same size as
  * the number of bytes that need to be pulled.
+ *
+ * skb_mac_header                                      skb->data
+ * |                                                       |
+ * v                                                       v
+ * |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
+ * +-----------------------+-----------------------+-------+-------+-------+
+ * |    Destination MAC    |      Source MAC       |  TPID |  TCI  | EType |
+ * +-----------------------+-----------------------+-------+-------+-------+
+ * ^                                               |               |
+ * |<--VLAN_HLEN-->to                              <---VLAN_HLEN--->
+ * from            |
+ *       >>>>>>>   v
+ *       >>>>>>>   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
+ *       >>>>>>>   +-----------------------+-----------------------+-------+
+ *       >>>>>>>   |    Destination MAC    |      Source MAC       | EType |
+ *                 +-----------------------+-----------------------+-------+
+ *                 ^                                                       ^
+ * (now part of    |                                                       |
+ *  skb->head)     skb_mac_header                                  skb->data
  */
-	skb_pull_rcsum(skb, VLAN_HLEN);
+struct sk_buff *dsa_8021q_remove_header(struct sk_buff *skb)
+{
+	u8 *from = skb_mac_header(skb);
+	u8 *dest = from + VLAN_HLEN;
+
+	memmove(dest, from, ETH_HLEN - VLAN_HLEN);
+	skb_pull(skb, VLAN_HLEN);
+	skb_push(skb, ETH_HLEN);
+	skb_reset_mac_header(skb);
+	skb_reset_mac_len(skb);
+	skb_pull_rcsum(skb, ETH_HLEN);
 
 	return skb;
 }
-EXPORT_SYMBOL_GPL(dsa_8021q_rcv);
+EXPORT_SYMBOL_GPL(dsa_8021q_remove_header);
 
 static const struct dsa_device_ops dsa_8021q_netdev_ops = {
 	.name		= "8021q",

net/dsa/tag_sja1105.c

@@ -13,6 +13,8 @@ static inline bool sja1105_is_link_local(const struct sk_buff *skb)
 	const struct ethhdr *hdr = eth_hdr(skb);
 	u64 dmac = ether_addr_to_u64(hdr->h_dest);
 
+	if (ntohs(hdr->h_proto) == ETH_P_SJA1105_META)
+		return false;
 	if ((dmac & SJA1105_LINKLOCAL_FILTER_A_MASK) ==
 		    SJA1105_LINKLOCAL_FILTER_A)
 		return true;
@@ -22,15 +24,61 @@ static inline bool sja1105_is_link_local(const struct sk_buff *skb)
 	return false;
 }
 
+struct sja1105_meta {
+	u64 tstamp;
+	u64 dmac_byte_4;
+	u64 dmac_byte_3;
+	u64 source_port;
+	u64 switch_id;
+};
+
+static void sja1105_meta_unpack(const struct sk_buff *skb,
+				struct sja1105_meta *meta)
+{
+	u8 *buf = skb_mac_header(skb) + ETH_HLEN;
+
+	/* UM10944.pdf section 4.2.17 AVB Parameters:
+	 * Structure of the meta-data follow-up frame.
+	 * It is in network byte order, so there are no quirks
+	 * while unpacking the meta frame.
+	 *
+	 * Also SJA1105 E/T only populates bits 23:0 of the timestamp
+	 * whereas P/Q/R/S does 32 bits. Since the structure is the
+	 * same and the E/T puts zeroes in the high-order byte, use
+	 * a unified unpacking command for both device series.
+	 */
+	packing(buf,     &meta->tstamp,     31, 0, 4, UNPACK, 0);
+	packing(buf + 4, &meta->dmac_byte_4, 7, 0, 1, UNPACK, 0);
+	packing(buf + 5, &meta->dmac_byte_3, 7, 0, 1, UNPACK, 0);
+	packing(buf + 6, &meta->source_port, 7, 0, 1, UNPACK, 0);
+	packing(buf + 7, &meta->switch_id,   7, 0, 1, UNPACK, 0);
+}
+
+static inline bool sja1105_is_meta_frame(const struct sk_buff *skb)
+{
+	const struct ethhdr *hdr = eth_hdr(skb);
+	u64 smac = ether_addr_to_u64(hdr->h_source);
+	u64 dmac = ether_addr_to_u64(hdr->h_dest);
+
+	if (smac != SJA1105_META_SMAC)
+		return false;
+	if (dmac != SJA1105_META_DMAC)
+		return false;
+	if (ntohs(hdr->h_proto) != ETH_P_SJA1105_META)
+		return false;
+	return true;
+}
+
 /* This is the first time the tagger sees the frame on RX.
- * Figure out if we can decode it, and if we can, annotate skb->cb with how we
- * plan to do that, so we don't need to check again in the rcv function.
+ * Figure out if we can decode it.
  */
 static bool sja1105_filter(const struct sk_buff *skb, struct net_device *dev)
 {
+	if (!dsa_port_is_vlan_filtering(dev->dsa_ptr))
+		return true;
 	if (sja1105_is_link_local(skb))
 		return true;
-	if (!dsa_port_is_vlan_filtering(dev->dsa_ptr))
+	if (sja1105_is_meta_frame(skb))
 		return true;
 	return false;
 }
@@ -62,25 +110,152 @@ static struct sk_buff *sja1105_xmit(struct sk_buff *skb,
 			     ((pcp << VLAN_PRIO_SHIFT) | tx_vid));
 }
 
+static void sja1105_transfer_meta(struct sk_buff *skb,
+				  const struct sja1105_meta *meta)
+{
+	struct ethhdr *hdr = eth_hdr(skb);
+
+	hdr->h_dest[3] = meta->dmac_byte_3;
+	hdr->h_dest[4] = meta->dmac_byte_4;
+	SJA1105_SKB_CB(skb)->meta_tstamp = meta->tstamp;
+}
+
+/* This is a simple state machine which follows the hardware mechanism of
+ * generating RX timestamps:
+ *
+ * After each timestampable skb (all traffic for which send_meta1 and
+ * send_meta0 is true, aka all MAC-filtered link-local traffic) a meta frame
+ * containing a partial timestamp is immediately generated by the switch and
+ * sent as a follow-up to the link-local frame on the CPU port.
+ *
+ * The meta frames have no unique identifier (such as sequence number) by which
+ * one may pair them to the correct timestampable frame.
+ * Instead, the switch has internal logic that ensures no frames are sent on
+ * the CPU port between a link-local timestampable frame and its corresponding
+ * meta follow-up. It also ensures strict ordering between ports (lower ports
+ * have higher priority towards the CPU port). For this reason, a per-port
+ * data structure is not needed/desirable.
+ *
+ * This function pairs the link-local frame with its partial timestamp from the
+ * meta follow-up frame. The full timestamp will be reconstructed later in a
+ * work queue.
+ */
+static struct sk_buff
+*sja1105_rcv_meta_state_machine(struct sk_buff *skb,
+				struct sja1105_meta *meta,
+				bool is_link_local,
+				bool is_meta)
+{
+	struct sja1105_port *sp;
+	struct dsa_port *dp;
+
+	dp = dsa_slave_to_port(skb->dev);
+	sp = dp->priv;
+
+	/* Step 1: A timestampable frame was received.
+	 * Buffer it until we get its meta frame.
+	 */
+	if (is_link_local && sp->data->hwts_rx_en) {
+		spin_lock(&sp->data->meta_lock);
+		/* Was this a link-local frame instead of the meta
+		 * that we were expecting?
+		 */
+		if (sp->data->stampable_skb) {
+			dev_err_ratelimited(dp->ds->dev,
+					    "Expected meta frame, is %12llx "
+					    "in the DSA master multicast filter?\n",
+					    SJA1105_META_DMAC);
+		}
+
+		/* Hold a reference to avoid dsa_switch_rcv
+		 * from freeing the skb.
+		 */
+		sp->data->stampable_skb = skb_get(skb);
+		spin_unlock(&sp->data->meta_lock);
+
+		/* Tell DSA we got nothing */
+		return NULL;
+
+	/* Step 2: The meta frame arrived.
+	 * Time to take the stampable skb out of the closet, annotate it
+	 * with the partial timestamp, and pretend that we received it
+	 * just now (basically masquerade the buffered frame as the meta
+	 * frame, which serves no further purpose).
+	 */
+	} else if (is_meta) {
+		struct sk_buff *stampable_skb;
+
+		spin_lock(&sp->data->meta_lock);
+
+		stampable_skb = sp->data->stampable_skb;
+		sp->data->stampable_skb = NULL;
+
+		/* Was this a meta frame instead of the link-local
+		 * that we were expecting?
+		 */
+		if (!stampable_skb) {
+			dev_err_ratelimited(dp->ds->dev,
+					    "Unexpected meta frame\n");
+			spin_unlock(&sp->data->meta_lock);
+			return NULL;
+		}
+
+		if (stampable_skb->dev != skb->dev) {
+			dev_err_ratelimited(dp->ds->dev,
+					    "Meta frame on wrong port\n");
+			spin_unlock(&sp->data->meta_lock);
+			return NULL;
+		}
+
+		/* Free the meta frame and give DSA the buffered stampable_skb
+		 * for further processing up the network stack.
+		 */
+		kfree_skb(skb);
+
+		skb = skb_copy(stampable_skb, GFP_ATOMIC);
+		if (!skb) {
+			dev_err_ratelimited(dp->ds->dev,
+					    "Failed to copy stampable skb\n");
+			return NULL;
+		}
+		sja1105_transfer_meta(skb, meta);
+		/* The cached copy will be freed now */
+		skb_unref(stampable_skb);
+
+		spin_unlock(&sp->data->meta_lock);
+	}
+
+	return skb;
+}
+
 static struct sk_buff *sja1105_rcv(struct sk_buff *skb,
 				   struct net_device *netdev,
 				   struct packet_type *pt)
 {
-	struct ethhdr *hdr = eth_hdr(skb);
-	u64 source_port, switch_id;
-	struct sk_buff *nskb;
+	struct sja1105_meta meta = {0};
+	int source_port, switch_id;
+	struct vlan_ethhdr *hdr;
 	u16 tpid, vid, tci;
+	bool is_link_local;
 	bool is_tagged;
+	bool is_meta;
 
-	nskb = dsa_8021q_rcv(skb, netdev, pt, &tpid, &tci);
-	is_tagged = (nskb && tpid == ETH_P_SJA1105);
-
-	skb->priority = (tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
-	vid = tci & VLAN_VID_MASK;
+	hdr = vlan_eth_hdr(skb);
+	tpid = ntohs(hdr->h_vlan_proto);
+	is_tagged = (tpid == ETH_P_SJA1105);
+	is_link_local = sja1105_is_link_local(skb);
+	is_meta = sja1105_is_meta_frame(skb);
 
 	skb->offload_fwd_mark = 1;
 
-	if (sja1105_is_link_local(skb)) {
+	if (is_tagged) {
+		/* Normal traffic path. */
+		tci = ntohs(hdr->h_vlan_TCI);
+		vid = tci & VLAN_VID_MASK;
+		source_port = dsa_8021q_rx_source_port(vid);
+		switch_id = dsa_8021q_rx_switch_id(vid);
+		skb->priority = (tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
+	} else if (is_link_local) {
 		/* Management traffic path. Switch embeds the switch ID and
 		 * port ID into bytes of the destination MAC, courtesy of
 		 * the incl_srcpt options.
@@ -90,10 +265,12 @@ static struct sk_buff *sja1105_rcv(struct sk_buff *skb,
 		/* Clear the DMAC bytes that were mangled by the switch */
 		hdr->h_dest[3] = 0;
 		hdr->h_dest[4] = 0;
+	} else if (is_meta) {
+		sja1105_meta_unpack(skb, &meta);
+		source_port = meta.source_port;
+		switch_id = meta.switch_id;
 	} else {
-		/* Normal traffic path. */
-		source_port = dsa_8021q_rx_source_port(vid);
-		switch_id = dsa_8021q_rx_switch_id(vid);
+		return NULL;
 	}
 
 	skb->dev = dsa_master_find_slave(netdev, switch_id, source_port);
@@ -106,10 +283,10 @@ static struct sk_buff *sja1105_rcv(struct sk_buff *skb,
 	 * it there, see dsa_switch_rcv: skb_push(skb, ETH_HLEN).
 	 */
 	if (is_tagged)
-		memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - VLAN_HLEN,
-			ETH_HLEN - VLAN_HLEN);
+		skb = dsa_8021q_remove_header(skb);
 
-	return skb;
+	return sja1105_rcv_meta_state_machine(skb, &meta, is_link_local,
+					      is_meta);
 }
 
 static struct dsa_device_ops sja1105_netdev_ops = {