Merge branch 'PTP-for-DSA-tag_ocelot_8021q'

Vladimir Oltean says:

====================
PTP for DSA tag_ocelot_8021q

Changes in v2:
Add stub definition for ocelot_port_inject_frame when switch driver is
not compiled in.

This is part two of the errata workaround begun here:
https://patchwork.kernel.org/project/netdevbpf/cover/20210129010009.3959398-1-olteanv@gmail.com/

Now that we have basic traffic support when we operate the Ocelot DSA
switches without an NPI port, it would be nice to regain some of the
features lost due to the lack of the NPI port functionality. An
important one is PTP timestamping, which is intimately tied to the DSA
frame header added by the NPI port: on TX, we put a "timestamp request
ID" in the Injection Frame Header, while on RX, the Extraction Frame
Header contains a partial 32-bit PTP timestamp. Get rid of the NPI port
and replace it with a VLAN-based tagger, and you lose PTP, right?

Well, not quite, this is what this patch series is about. The NPI port
is basically a regular Ethernet port configured to service the packets
in and out of the switch's CPU port module (which has other non-DSA I/O
mechanisms too, such as register-based MMIO and DMA). If we disable the
NPI port, we can in theory still access the packets delivered to the CPU
port module by doing exactly what the ocelot switchdev driver does:
extracting Ethernet packets through registers (yes, it is as icky as it
sounds).

However, there's a catch. The Felix switch was integrated into NXP
LS1028A with the idea in mind that it will operate as DSA, i.e. using
the CPU port module connected to the NPI port, not having I/O over
register-based MMIO which is painfully slow and CPU intensive. So
register-based packet I/O not supposed to work - those registers aren't
even documented in the hardware reference manual for Felix. However
they kinda do, with the exception of the fact that an RX interrupt was
really not wired to the CPU cores - so we don't know when the CPU port
module receives a new packet. But we can hack even around that, by
replicating every packet that goes to the CPU port module and making it
also go to a plain internal Ethernet port. Then drop the Ethernet packet
and read the other copy of it from the CPU port module, this time
annotated with the much-wanted RX timestamp.

This is all fine and it works, but it does raise some questions about
what DSA even is anymore, if we start having switches that inject some
of their packets over Ethernet and some through registers, where do we
draw the line. In principle I believe these concerns are founded, but at
the same time, the way that the Felix driver uses register MMIO based
packet I/O is fundamentally the same as any other DSA driver capable of
PTP makes use of a side-channel for timestamps like a FIFO (just that
this one is a lot more complicated, and comes with the entire actual
packet, not just the timestamp).

Nonetheless, I tried to keep the extra pressure added by this ERR
workaround upon the DSA subsystem as small as possible, so some of the
patches are just a revisit of some of Andrew's complaints w.r.t. the
fact that tag_ocelot already violates any driver <-> tagger boundary,
and as a consequence, is not able to be used on testbeds such as
dsa_loop (which it now can). So now, the tag_ocelot and tag_ocelot_8021q
drivers should be dsa_loop-clean, and have the ERR workarounds as
self-contained as possible, using all the designated features for PTP
timestamping and nothing more.

Comments appreciated.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 115 insertions, 163 deletions

diff --git a/net/dsa/tag_ocelot.c b/net/dsa/tag_ocelot.c
index 16a1afd5b8e1..a7dd61c8e005 100644
--- a/net/dsa/tag_ocelot.c
+++ b/net/dsa/tag_ocelot.c
@@ -1,174 +1,74 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Copyright 2019 NXP Semiconductors
  */
+#include <linux/dsa/ocelot.h>
 #include <soc/mscc/ocelot.h>
-#include <linux/packing.h>
 #include "dsa_priv.h"
 
-/* The CPU injection header and the CPU extraction header can have 3 types of
- * prefixes: long, short and no prefix. The format of the header itself is the
- * same in all 3 cases.
- *
- * Extraction with long prefix:
- *
- * +-------------------+-------------------+------+------+------------+-------+
- * | ff:ff:ff:ff:ff:ff | ff:ff:ff:ff:ff:ff | 8880 | 000a | extraction | frame |
- * |                   |                   |      |      |   header   |       |
- * +-------------------+-------------------+------+------+------------+-------+
- *        48 bits             48 bits      16 bits 16 bits  128 bits
- *
- * Extraction with short prefix:
- *
- *                                         +------+------+------------+-------+
- *                                         | 8880 | 000a | extraction | frame |
- *                                         |      |      |   header   |       |
- *                                         +------+------+------------+-------+
- *                                         16 bits 16 bits  128 bits
- *
- * Extraction with no prefix:
- *
- *                                                       +------------+-------+
- *                                                       | extraction | frame |
- *                                                       |   header   |       |
- *                                                       +------------+-------+
- *                                                          128 bits
- *
- *
- * Injection with long prefix:
- *
- * +-------------------+-------------------+------+------+------------+-------+
- * |      any dmac     |      any smac     | 8880 | 000a | injection  | frame |
- * |                   |                   |      |      |   header   |       |
- * +-------------------+-------------------+------+------+------------+-------+
- *        48 bits             48 bits      16 bits 16 bits  128 bits
- *
- * Injection with short prefix:
- *
- *                                         +------+------+------------+-------+
- *                                         | 8880 | 000a | injection  | frame |
- *                                         |      |      |   header   |       |
- *                                         +------+------+------------+-------+
- *                                         16 bits 16 bits  128 bits
- *
- * Injection with no prefix:
- *
- *                                                       +------------+-------+
- *                                                       | injection  | frame |
- *                                                       |   header   |       |
- *                                                       +------------+-------+
- *                                                          128 bits
- *
- * The injection header looks like this (network byte order, bit 127
- * is part of lowest address byte in memory, bit 0 is part of highest
- * address byte):
- *
- *         +------+------+------+------+------+------+------+------+
- * 127:120 |BYPASS| MASQ |          MASQ_PORT        |REW_OP|REW_OP|
- *         +------+------+------+------+------+------+------+------+
- * 119:112 |                         REW_OP                        |
- *         +------+------+------+------+------+------+------+------+
- * 111:104 |                         REW_VAL                       |
- *         +------+------+------+------+------+------+------+------+
- * 103: 96 |                         REW_VAL                       |
- *         +------+------+------+------+------+------+------+------+
- *  95: 88 |                         REW_VAL                       |
- *         +------+------+------+------+------+------+------+------+
- *  87: 80 |                         REW_VAL                       |
- *         +------+------+------+------+------+------+------+------+
- *  79: 72 |                          RSV                          |
- *         +------+------+------+------+------+------+------+------+
- *  71: 64 |            RSV            |           DEST            |
- *         +------+------+------+------+------+------+------+------+
- *  63: 56 |                         DEST                          |
- *         +------+------+------+------+------+------+------+------+
- *  55: 48 |                          RSV                          |
- *         +------+------+------+------+------+------+------+------+
- *  47: 40 |  RSV |         SRC_PORT          |     RSV     |TFRM_TIMER|
- *         +------+------+------+------+------+------+------+------+
- *  39: 32 |     TFRM_TIMER     |               RSV                |
- *         +------+------+------+------+------+------+------+------+
- *  31: 24 |  RSV |  DP  |   POP_CNT   |           CPUQ            |
- *         +------+------+------+------+------+------+------+------+
- *  23: 16 |           CPUQ            |      QOS_CLASS     |TAG_TYPE|
- *         +------+------+------+------+------+------+------+------+
- *  15:  8 |         PCP        |  DEI |            VID            |
- *         +------+------+------+------+------+------+------+------+
- *   7:  0 |                          VID                          |
- *         +------+------+------+------+------+------+------+------+
- *
- * And the extraction header looks like this:
- *
- *         +------+------+------+------+------+------+------+------+
- * 127:120 |  RSV |                  REW_OP                        |
- *         +------+------+------+------+------+------+------+------+
- * 119:112 |       REW_OP       |              REW_VAL             |
- *         +------+------+------+------+------+------+------+------+
- * 111:104 |                         REW_VAL                       |
- *         +------+------+------+------+------+------+------+------+
- * 103: 96 |                         REW_VAL                       |
- *         +------+------+------+------+------+------+------+------+
- *  95: 88 |                         REW_VAL                       |
- *         +------+------+------+------+------+------+------+------+
- *  87: 80 |       REW_VAL      |               LLEN               |
- *         +------+------+------+------+------+------+------+------+
- *  79: 72 | LLEN |                      WLEN                      |
- *         +------+------+------+------+------+------+------+------+
- *  71: 64 | WLEN |                      RSV                       |
- *         +------+------+------+------+------+------+------+------+
- *  63: 56 |                          RSV                          |
- *         +------+------+------+------+------+------+------+------+
- *  55: 48 |                          RSV                          |
- *         +------+------+------+------+------+------+------+------+
- *  47: 40 | RSV  |          SRC_PORT         |       ACL_ID       |
- *         +------+------+------+------+------+------+------+------+
- *  39: 32 |       ACL_ID       |  RSV |         SFLOW_ID          |
- *         +------+------+------+------+------+------+------+------+
- *  31: 24 |ACL_HIT| DP  |  LRN_FLAGS  |           CPUQ            |
- *         +------+------+------+------+------+------+------+------+
- *  23: 16 |           CPUQ            |      QOS_CLASS     |TAG_TYPE|
- *         +------+------+------+------+------+------+------+------+
- *  15:  8 |         PCP        |  DEI |            VID            |
- *         +------+------+------+------+------+------+------+------+
- *   7:  0 |                          VID                          |
- *         +------+------+------+------+------+------+------+------+
- */
+static void ocelot_xmit_ptp(struct dsa_port *dp, void *injection,
+			    struct sk_buff *clone)
+{
+	struct ocelot *ocelot = dp->ds->priv;
+	struct ocelot_port *ocelot_port;
+	u64 rew_op;
 
-static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
-				   struct net_device *netdev)
+	ocelot_port = ocelot->ports[dp->index];
+	rew_op = ocelot_port->ptp_cmd;
+
+	/* Retrieve timestamp ID populated inside skb->cb[0] of the
+	 * clone by ocelot_port_add_txtstamp_skb
+	 */
+	if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP)
+		rew_op |= clone->cb[0] << 3;
+
+	ocelot_ifh_set_rew_op(injection, rew_op);
+}
+
+static void ocelot_xmit_common(struct sk_buff *skb, struct net_device *netdev,
+			       __be32 ifh_prefix, void **ifh)
 {
 	struct dsa_port *dp = dsa_slave_to_port(netdev);
 	struct sk_buff *clone = DSA_SKB_CB(skb)->clone;
 	struct dsa_switch *ds = dp->ds;
-	struct ocelot *ocelot = ds->priv;
-	struct ocelot_port *ocelot_port;
-	u8 *prefix, *injection;
-	u64 qos_class, rew_op;
-
-	ocelot_port = ocelot->ports[dp->index];
+	void *injection;
+	__be32 *prefix;
 
 	injection = skb_push(skb, OCELOT_TAG_LEN);
-
 	prefix = skb_push(skb, OCELOT_SHORT_PREFIX_LEN);
 
-	memcpy(prefix, ocelot_port->xmit_template, OCELOT_TOTAL_TAG_LEN);
-
-	/* Fix up the fields which are not statically determined
-	 * in the template
-	 */
-	qos_class = skb->priority;
-	packing(injection, &qos_class, 19,  17, OCELOT_TAG_LEN, PACK, 0);
+	*prefix = ifh_prefix;
+	memset(injection, 0, OCELOT_TAG_LEN);
+	ocelot_ifh_set_bypass(injection, 1);
+	ocelot_ifh_set_src(injection, ds->num_ports);
+	ocelot_ifh_set_qos_class(injection, skb->priority);
 
 	/* TX timestamping was requested */
-	if (clone) {
-		rew_op = ocelot_port->ptp_cmd;
-		/* Retrieve timestamp ID populated inside skb->cb[0] of the
-		 * clone by ocelot_port_add_txtstamp_skb
-		 */
-		if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP)
-			rew_op |= clone->cb[0] << 3;
+	if (clone)
+		ocelot_xmit_ptp(dp, injection, clone);
 
-		packing(injection, &rew_op, 125, 117, OCELOT_TAG_LEN, PACK, 0);
-	}
+	*ifh = injection;
+}
+
+static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
+				   struct net_device *netdev)
+{
+	struct dsa_port *dp = dsa_slave_to_port(netdev);
+	void *injection;
+
+	ocelot_xmit_common(skb, netdev, cpu_to_be32(0x8880000a), &injection);
+	ocelot_ifh_set_dest(injection, BIT(dp->index));
+
+	return skb;
+}
+
+static struct sk_buff *seville_xmit(struct sk_buff *skb,
+				    struct net_device *netdev)
+{
+	struct dsa_port *dp = dsa_slave_to_port(netdev);
+	void *injection;
+
+	ocelot_xmit_common(skb, netdev, cpu_to_be32(0x88800005), &injection);
+	seville_ifh_set_dest(injection, BIT(dp->index));
 
 	return skb;
 }
@@ -177,12 +77,10 @@ static struct sk_buff *ocelot_rcv(struct sk_buff *skb,
 				  struct net_device *netdev,
 				  struct packet_type *pt)
 {
-	struct dsa_port *cpu_dp = netdev->dsa_ptr;
-	struct dsa_switch *ds = cpu_dp->ds;
-	struct ocelot *ocelot = ds->priv;
 	u64 src_port, qos_class;
 	u64 vlan_tci, tag_type;
 	u8 *start = skb->data;
+	struct dsa_port *dp;
 	u8 *extraction;
 	u16 vlan_tpid;
 
@@ -210,10 +108,10 @@ static struct sk_buff *ocelot_rcv(struct sk_buff *skb,
 	/* Remove from inet csum the extraction header */
 	skb_postpull_rcsum(skb, start, OCELOT_TOTAL_TAG_LEN);
 
-	packing(extraction, &src_port,  46, 43, OCELOT_TAG_LEN, UNPACK, 0);
-	packing(extraction, &qos_class, 19, 17, OCELOT_TAG_LEN, UNPACK, 0);
-	packing(extraction, &tag_type,  16, 16, OCELOT_TAG_LEN, UNPACK, 0);
-	packing(extraction, &vlan_tci,  15,  0, OCELOT_TAG_LEN, UNPACK, 0);
+	ocelot_xfh_get_src_port(extraction, &src_port);
+	ocelot_xfh_get_qos_class(extraction, &qos_class);
+	ocelot_xfh_get_tag_type(extraction, &tag_type);
+	ocelot_xfh_get_vlan_tci(extraction, &vlan_tci);
 
 	skb->dev = dsa_master_find_slave(netdev, 0, src_port);
 	if (!skb->dev)
@@ -243,9 +141,10 @@ static struct sk_buff *ocelot_rcv(struct sk_buff *skb,
 	 * equal to the pvid of the ingress port and should not be used for
 	 * processing.
 	 */
+	dp = dsa_slave_to_port(skb->dev);
 	vlan_tpid = tag_type ? ETH_P_8021AD : ETH_P_8021Q;
 
-	if (ocelot->ports[src_port]->vlan_aware &&
+	if (dsa_port_is_vlan_filtering(dp) &&
 	    eth_hdr(skb)->h_proto == htons(vlan_tpid)) {
 		u16 dummy_vlan_tci;
 
@@ -267,7 +166,26 @@ static const struct dsa_device_ops ocelot_netdev_ops = {
 	.promisc_on_master	= true,
 };
 
-MODULE_LICENSE("GPL v2");
+DSA_TAG_DRIVER(ocelot_netdev_ops);
 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_OCELOT);
 
-module_dsa_tag_driver(ocelot_netdev_ops);
+static const struct dsa_device_ops seville_netdev_ops = {
+	.name			= "seville",
+	.proto			= DSA_TAG_PROTO_SEVILLE,
+	.xmit			= seville_xmit,
+	.rcv			= ocelot_rcv,
+	.overhead		= OCELOT_TOTAL_TAG_LEN,
+	.promisc_on_master	= true,
+};
+
+DSA_TAG_DRIVER(seville_netdev_ops);
+MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_SEVILLE);
+
+static struct dsa_tag_driver *ocelot_tag_driver_array[] = {
+	&DSA_TAG_DRIVER_NAME(ocelot_netdev_ops),
+	&DSA_TAG_DRIVER_NAME(seville_netdev_ops),
+};
+
+module_dsa_tag_drivers(ocelot_tag_driver_array);
+
+MODULE_LICENSE("GPL v2");
diff --git a/net/dsa/tag_ocelot_8021q.c b/net/dsa/tag_ocelot_8021q.c
index 8991ebf098a3..5f3e8e124a82 100644
--- a/net/dsa/tag_ocelot_8021q.c
+++ b/net/dsa/tag_ocelot_8021q.c
@@ -9,8 +9,36 @@
  *   that on egress
  */
 #include <linux/dsa/8021q.h>
+#include <soc/mscc/ocelot.h>
+#include <soc/mscc/ocelot_ptp.h>
 #include "dsa_priv.h"
 
+static struct sk_buff *ocelot_xmit_ptp(struct dsa_port *dp,
+				       struct sk_buff *skb,
+				       struct sk_buff *clone)
+{
+	struct ocelot *ocelot = dp->ds->priv;
+	struct ocelot_port *ocelot_port;
+	int port = dp->index;
+	u32 rew_op;
+
+	if (!ocelot_can_inject(ocelot, 0))
+		return NULL;
+
+	ocelot_port = ocelot->ports[port];
+	rew_op = ocelot_port->ptp_cmd;
+
+	/* Retrieve timestamp ID populated inside skb->cb[0] of the
+	 * clone by ocelot_port_add_txtstamp_skb
+	 */
+	if (ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP)
+		rew_op |= clone->cb[0] << 3;
+
+	ocelot_port_inject_frame(ocelot, port, 0, rew_op, skb);
+
+	return NULL;
+}
+
 static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
 				   struct net_device *netdev)
 {
@@ -18,6 +46,11 @@ static struct sk_buff *ocelot_xmit(struct sk_buff *skb,
 	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);
+	struct sk_buff *clone = DSA_SKB_CB(skb)->clone;
+
+	/* TX timestamping was requested, so inject through MMIO */
+	if (clone)
+		return ocelot_xmit_ptp(dp, skb, clone);
 
 	return dsa_8021q_xmit(skb, netdev, ETH_P_8021Q,
 			      ((pcp << VLAN_PRIO_SHIFT) | tx_vid));
@@ -60,6 +93,7 @@ static const struct dsa_device_ops ocelot_8021q_netdev_ops = {
 	.xmit			= ocelot_xmit,
 	.rcv			= ocelot_rcv,
 	.overhead		= VLAN_HLEN,
+	.promisc_on_master	= true,
 };
 
 MODULE_LICENSE("GPL v2");