Merge branch 'Traffic-support-for-SJA1105-DSA-driver'

Vladimir Oltean says:

====================
Traffic support for SJA1105 DSA driver

This patch set is a continuation of the "NXP SJA1105 DSA driver" v3
series, which was split in multiple pieces for easier review.

Supporting a fully-featured (traffic-capable) driver for this switch
requires some rework in DSA and also leaves behind a more generic
infrastructure for other dumb switches that rely on 802.1Q pseudo-switch
tagging for port separation. Among the DSA changes required are:

* Generic xmit and rcv functions for pushing/popping 802.1Q tags on
  skb's. These are modeled as a tagging protocol of its own but which
  must be customized by drivers to fit their own hardware possibilities.

* Permitting the .setup callback to invoke switchdev operations that
  will loop back into the driver through the switchdev notifier chain.

The SJA1105 driver then proceeds to extend this 8021q switch tagging
protocol while adding its own (tag_sja1105). This is done because
the driver actually implements a "dual tagger":

* For normal traffic it uses 802.1Q tags

* For management (multicast DMAC) frames the switch has native support
  for recognizing and annotating these with source port and switch id
  information.

Because this is a "dual tagger", decoding of management frames should
still function when regular traffic can't (under a bridge with VLAN
filtering).
There was intervention in the DSA receive hotpath, where a new
filtering function called from eth_type_trans() is needed. This is
useful in the general sense for switches that might actually have some
limited means of source port decoding, such as only for management
traffic, but not for everything.
In order for the 802.1Q tagging protocol (which cannot be enabled under
all conditions, unlike the management traffic decoding) to not be an
all-or-nothing choice, the filtering function matches everything that
can be decoded, and everything else is left to pass to the master
netdevice.

Lastly, DSA core support was added for drivers to request skb deferral.
SJA1105 needs this for SPI intervention during transmission of link-local
traffic. This is not done from within the tagger.

Some patches were carried over unchanged from the previous patchset
(01/09). Others were slightly reworked while adapting to the recent
changes in "Make DSA tag drivers kernel modules" (02/09).

The introduction of some structures (DSA_SKB_CB, dp->priv) may seem a
little premature at this point and the new structures under-utilized.
The reason is that traffic support has been rewritten with PTP
timestamping in mind, and then I removed the timestamping code from the
current submission (1. it is a different topic, 2. it does not work very
well yet). On demand I can provide the timestamping patchset as a RFC
though.

"NXP SJA1105 DSA driver" v3 patchset can be found at:
https://lkml.org/lkml/2019/4/12/978

v1 patchset can be found at:
https://lkml.org/lkml/2019/5/3/877

Changes in v2:

* Made the deferred xmit workqueue also be drained on the netdev suspend
  callback, not just on ndo_stop.

* Added clarification about how other netdevices may be bridged with the
  switch ports.

v2 patchset can be found at:
https://www.spinics.net/lists/netdev/msg568818.html

Changes in v3:

* Exported the dsa_port_vid_add and dsa_port_vid_del symbols to fix an
  error reported by the kbuild test robot

* Fixed the following checkpatch warnings in 05/10:
  Macro argument reuse 'skb' - possible side-effects?
  Macro argument reuse 'clone' - possible side-effects?

* Added a commit description to the documentation patch (10/10)
====================

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

3 files changed, 170 insertions, 9 deletions

diff --git a/include/linux/dsa/8021q.h b/include/linux/dsa/8021q.h
new file mode 100644
index 000000000000..3911e0586478
--- /dev/null
+++ b/include/linux/dsa/8021q.h
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: GPL-2.0
+ * Copyright (c) 2019, Vladimir Oltean <olteanv@gmail.com>
+ */
+
+#ifndef _NET_DSA_8021Q_H
+#define _NET_DSA_8021Q_H
+
+#include <linux/types.h>
+
+struct dsa_switch;
+struct sk_buff;
+struct net_device;
+struct packet_type;
+
+#if IS_ENABLED(CONFIG_NET_DSA_TAG_8021Q)
+
+int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int index,
+				 bool enabled);
+
+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);
+
+int dsa_8021q_rx_switch_id(u16 vid);
+
+int dsa_8021q_rx_source_port(u16 vid);
+
+#else
+
+int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int index,
+				 bool enabled)
+{
+	return 0;
+}
+
+struct sk_buff *dsa_8021q_xmit(struct sk_buff *skb, struct net_device *netdev,
+			       u16 tpid, u16 tci)
+{
+	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;
+}
+
+u16 dsa_8021q_rx_vid(struct dsa_switch *ds, int port)
+{
+	return 0;
+}
+
+int dsa_8021q_rx_switch_id(u16 vid)
+{
+	return 0;
+}
+
+int dsa_8021q_rx_source_port(u16 vid)
+{
+	return 0;
+}
+
+#endif /* IS_ENABLED(CONFIG_NET_DSA_TAG_8021Q) */
+
+#endif /* _NET_DSA_8021Q_H */
diff --git a/include/linux/dsa/sja1105.h b/include/linux/dsa/sja1105.h
index abf3977e34fd..603a02e5a8cb 100644
--- a/include/linux/dsa/sja1105.h
+++ b/include/linux/dsa/sja1105.h
@@ -2,22 +2,39 @@
  * Copyright (c) 2019, Vladimir Oltean <olteanv@gmail.com>
  */
 
-/* Included by drivers/net/dsa/sja1105/sja1105.h */
+/* Included by drivers/net/dsa/sja1105/sja1105.h and net/dsa/tag_sja1105.c */
 
 #ifndef _NET_DSA_SJA1105_H
 #define _NET_DSA_SJA1105_H
 
+#include <linux/skbuff.h>
 #include <linux/etherdevice.h>
+#include <net/dsa.h>
 
 #define ETH_P_SJA1105				ETH_P_DSA_8021Q
 
-/* The switch can only be convinced to stay in unmanaged mode and not trap any
- * link-local traffic by actually telling it to filter frames sent at the
- * 00:00:00:00:00:00 destination MAC.
- */
-#define SJA1105_LINKLOCAL_FILTER_A		0x000000000000ull
-#define SJA1105_LINKLOCAL_FILTER_A_MASK		0xFFFFFFFFFFFFull
-#define SJA1105_LINKLOCAL_FILTER_B		0x000000000000ull
-#define SJA1105_LINKLOCAL_FILTER_B_MASK		0xFFFFFFFFFFFFull
+/* IEEE 802.3 Annex 57A: Slow Protocols PDUs (01:80:C2:xx:xx:xx) */
+#define SJA1105_LINKLOCAL_FILTER_A		0x0180C2000000ull
+#define SJA1105_LINKLOCAL_FILTER_A_MASK		0xFFFFFF000000ull
+/* IEEE 1588 Annex F: Transport of PTP over Ethernet (01:1B:19:xx:xx:xx) */
+#define SJA1105_LINKLOCAL_FILTER_B		0x011B19000000ull
+#define SJA1105_LINKLOCAL_FILTER_B_MASK		0xFFFFFF000000ull
+
+enum sja1105_frame_type {
+	SJA1105_FRAME_TYPE_NORMAL = 0,
+	SJA1105_FRAME_TYPE_LINK_LOCAL,
+};
+
+struct sja1105_skb_cb {
+	enum sja1105_frame_type type;
+};
+
+#define SJA1105_SKB_CB(skb) \
+	((struct sja1105_skb_cb *)DSA_SKB_CB_PRIV(skb))
+
+struct sja1105_port {
+	struct dsa_port *dp;
+	int mgmt_slot;
+};
 
 #endif /* _NET_DSA_SJA1105_H */
diff --git a/include/net/dsa.h b/include/net/dsa.h
index 18db7b8e7a8e..6aaaadd6a413 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -42,6 +42,8 @@ struct phylink_link_state;
 #define DSA_TAG_PROTO_MTK_VALUE			9
 #define DSA_TAG_PROTO_QCA_VALUE			10
 #define DSA_TAG_PROTO_TRAILER_VALUE		11
+#define DSA_TAG_PROTO_8021Q_VALUE		12
+#define DSA_TAG_PROTO_SJA1105_VALUE		13
 
 enum dsa_tag_protocol {
 	DSA_TAG_PROTO_NONE		= DSA_TAG_PROTO_NONE_VALUE,
@@ -56,6 +58,8 @@ enum dsa_tag_protocol {
 	DSA_TAG_PROTO_MTK		= DSA_TAG_PROTO_MTK_VALUE,
 	DSA_TAG_PROTO_QCA		= DSA_TAG_PROTO_QCA_VALUE,
 	DSA_TAG_PROTO_TRAILER		= DSA_TAG_PROTO_TRAILER_VALUE,
+	DSA_TAG_PROTO_8021Q		= DSA_TAG_PROTO_8021Q_VALUE,
+	DSA_TAG_PROTO_SJA1105		= DSA_TAG_PROTO_SJA1105_VALUE,
 };
 
 struct packet_type;
@@ -67,6 +71,11 @@ struct dsa_device_ops {
 			       struct packet_type *pt);
 	int (*flow_dissect)(const struct sk_buff *skb, __be16 *proto,
 			    int *offset);
+	/* Used to determine which traffic should match the DSA filter in
+	 * eth_type_trans, and which, if any, should bypass it and be processed
+	 * as regular on the master net device.
+	 */
+	bool (*filter)(const struct sk_buff *skb, struct net_device *dev);
 	unsigned int overhead;
 	const char *name;
 	enum dsa_tag_protocol proto;
@@ -76,6 +85,38 @@ struct dsa_device_ops {
 #define MODULE_ALIAS_DSA_TAG_DRIVER(__proto)				\
 	MODULE_ALIAS(DSA_TAG_DRIVER_ALIAS __stringify(__proto##_VALUE))
 
+struct dsa_skb_cb {
+	struct sk_buff *clone;
+	bool deferred_xmit;
+};
+
+struct __dsa_skb_cb {
+	struct dsa_skb_cb cb;
+	u8 priv[48 - sizeof(struct dsa_skb_cb)];
+};
+
+#define __DSA_SKB_CB(skb) ((struct __dsa_skb_cb *)((skb)->cb))
+
+#define DSA_SKB_CB(skb) ((struct dsa_skb_cb *)((skb)->cb))
+
+#define DSA_SKB_CB_COPY(nskb, skb)		\
+	{ *__DSA_SKB_CB(nskb) = *__DSA_SKB_CB(skb); }
+
+#define DSA_SKB_CB_ZERO(skb)			\
+	{ *__DSA_SKB_CB(skb) = (struct __dsa_skb_cb) {0}; }
+
+#define DSA_SKB_CB_PRIV(skb)			\
+	((void *)(skb)->cb + offsetof(struct __dsa_skb_cb, priv))
+
+#define DSA_SKB_CB_CLONE(_clone, _skb)		\
+	{					\
+		struct sk_buff *clone = _clone;	\
+		struct sk_buff *skb = _skb;	\
+						\
+		DSA_SKB_CB_COPY(clone, skb);	\
+		DSA_SKB_CB(skb)->clone = clone; \
+	}
+
 struct dsa_switch_tree {
 	struct list_head	list;
 
@@ -146,6 +187,7 @@ struct dsa_port {
 	struct dsa_switch_tree *dst;
 	struct sk_buff *(*rcv)(struct sk_buff *skb, struct net_device *dev,
 			       struct packet_type *pt);
+	bool (*filter)(const struct sk_buff *skb, struct net_device *dev);
 
 	enum {
 		DSA_PORT_TYPE_UNUSED = 0,
@@ -166,6 +208,16 @@ struct dsa_port {
 	struct net_device	*bridge_dev;
 	struct devlink_port	devlink_port;
 	struct phylink		*pl;
+
+	struct work_struct	xmit_work;
+	struct sk_buff_head	xmit_queue;
+
+	/*
+	 * Give the switch driver somewhere to hang its per-port private data
+	 * structures (accessible from the tagger).
+	 */
+	void *priv;
+
 	/*
 	 * Original copy of the master netdev ethtool_ops
 	 */
@@ -500,6 +552,12 @@ struct dsa_switch_ops {
 				 struct sk_buff *clone, unsigned int type);
 	bool	(*port_rxtstamp)(struct dsa_switch *ds, int port,
 				 struct sk_buff *skb, unsigned int type);
+
+	/*
+	 * Deferred frame Tx
+	 */
+	netdev_tx_t (*port_deferred_xmit)(struct dsa_switch *ds, int port,
+					  struct sk_buff *skb);
 };
 
 struct dsa_switch_driver {
@@ -518,6 +576,15 @@ static inline bool netdev_uses_dsa(struct net_device *dev)
 	return false;
 }
 
+static inline bool dsa_can_decode(const struct sk_buff *skb,
+				  struct net_device *dev)
+{
+#if IS_ENABLED(CONFIG_NET_DSA)
+	return !dev->dsa_ptr->filter || dev->dsa_ptr->filter(skb, dev);
+#endif
+	return false;
+}
+
 struct dsa_switch *dsa_switch_alloc(struct device *dev, size_t n);
 void dsa_unregister_switch(struct dsa_switch *ds);
 int dsa_register_switch(struct dsa_switch *ds);
@@ -586,6 +653,7 @@ static inline int call_dsa_notifiers(unsigned long val, struct net_device *dev,
 #define BRCM_TAG_GET_QUEUE(v)		((v) & 0xff)
 
 
+netdev_tx_t dsa_enqueue_skb(struct sk_buff *skb, struct net_device *dev);
 int dsa_port_get_phy_strings(struct dsa_port *dp, uint8_t *data);
 int dsa_port_get_ethtool_phy_stats(struct dsa_port *dp, uint64_t *data);
 int dsa_port_get_phy_sset_count(struct dsa_port *dp);