Merge branch 'dsa-tagger-storage'

Vladimir Oltean says:

====================
Replace DSA dp->priv with tagger-owned storage

Ansuel's recent work on qca8k register access over Ethernet:
https://patchwork.kernel.org/project/netdevbpf/cover/20211207145942.7444-1-ansuelsmth@gmail.com/
has triggered me to do something which I should've done for a longer
time:
https://patchwork.kernel.org/project/netdevbpf/patch/20211109095013.27829-7-martin.kaistra@linutronix.de/#24585521
which is to replace dp->priv with something that has less caveats.

The dp->priv was introduced when sja1105 needed to hold stateful
information in the tagging protocol driver. In that design, dp->priv
held memory allocated by the switch driver, because the tagging protocol
driver design was 100% stateless.

Some years have passed and others have started to feel the need for
stateful information kept by the tagger, as well as passing data back
and forth between the tagging protocol driver and the switch driver.
This isn't possible cleanly in DSA due to a circular dependency which
leads to broken module autoloading:
https://lore.kernel.org/netdev/20210908220834.d7gmtnwrorhharna@skbuf/

This patchset introduces a framework that resembles something normal,
which allows data to be passed from the tagging protocol driver (things
like switch management packets, which aren't intended for the network
stack) to the switch driver, while the tagging protocol still remains
more or less stateless. The overall design of the framework was
discussed with Ansuel too and it appears to be flexible enough to cover
the "register access over Ethernet" use case. Additionally, the existing
uses of dp->priv, which have mainly to do with PTP timestamping, have
also been migrated.

Changes in v2:
Fix transient build breakage in patch 5/11 due to a missing parenthesis,
https://patchwork.hopto.org/static/nipa/592567/12665213/build_clang/
and another transient build warning in patch 4/11 that for some reason
doesn't appear in my W=1 C=1 build.
https://patchwork.hopto.org/static/nipa/592567/12665209/build_clang/stderr
====================

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

2 files changed, 32 insertions, 41 deletions

diff --git a/include/linux/dsa/ocelot.h b/include/linux/dsa/ocelot.h
index 7ee708ad7df2..dca2969015d8 100644
--- a/include/linux/dsa/ocelot.h
+++ b/include/linux/dsa/ocelot.h
@@ -8,6 +8,7 @@
 #include <linux/kthread.h>
 #include <linux/packing.h>
 #include <linux/skbuff.h>
+#include <net/dsa.h>
 
 struct ocelot_skb_cb {
 	struct sk_buff *clone;
@@ -168,11 +169,18 @@ struct felix_deferred_xmit_work {
 	struct kthread_work work;
 };
 
-struct felix_port {
+struct ocelot_8021q_tagger_data {
 	void (*xmit_work_fn)(struct kthread_work *work);
-	struct kthread_worker *xmit_worker;
 };
 
+static inline struct ocelot_8021q_tagger_data *
+ocelot_8021q_tagger_data(struct dsa_switch *ds)
+{
+	BUG_ON(ds->dst->tag_ops->proto != DSA_TAG_PROTO_OCELOT_8021Q);
+
+	return ds->tagger_data;
+}
+
 static inline void ocelot_xfh_get_rew_val(void *extraction, u64 *rew_val)
 {
 	packing(extraction, rew_val, 116, 85, OCELOT_TAG_LEN, UNPACK, 0);
diff --git a/include/linux/dsa/sja1105.h b/include/linux/dsa/sja1105.h
index e6c78be40bde..e9cb1ae6d742 100644
--- a/include/linux/dsa/sja1105.h
+++ b/include/linux/dsa/sja1105.h
@@ -35,23 +35,26 @@
 #define SJA1105_META_SMAC			0x222222222222ull
 #define SJA1105_META_DMAC			0x0180C200000Eull
 
-#define SJA1105_HWTS_RX_EN			0
+enum sja1110_meta_tstamp {
+	SJA1110_META_TSTAMP_TX = 0,
+	SJA1110_META_TSTAMP_RX = 1,
+};
 
-/* Global tagger data: each struct sja1105_port has a reference to
- * the structure defined in struct sja1105_private.
- */
+struct sja1105_deferred_xmit_work {
+	struct dsa_port *dp;
+	struct sk_buff *skb;
+	struct kthread_work work;
+};
+
+/* Global tagger data */
 struct sja1105_tagger_data {
-	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;
-	unsigned long state;
-	u8 ts_id;
-	/* Used on SJA1110 where meta frames are generated only for
-	 * 2-step TX timestamps
-	 */
-	struct sk_buff_head skb_txtstamp_queue;
+	/* Tagger to switch */
+	void (*xmit_work_fn)(struct kthread_work *work);
+	void (*meta_tstamp_handler)(struct dsa_switch *ds, int port, u8 ts_id,
+				    enum sja1110_meta_tstamp dir, u64 tstamp);
+	/* Switch to tagger */
+	bool (*rxtstamp_get_state)(struct dsa_switch *ds);
+	void (*rxtstamp_set_state)(struct dsa_switch *ds, bool on);
 };
 
 struct sja1105_skb_cb {
@@ -64,32 +67,12 @@ struct sja1105_skb_cb {
 #define SJA1105_SKB_CB(skb) \
 	((struct sja1105_skb_cb *)((skb)->cb))
 
-struct sja1105_port {
-	struct kthread_worker *xmit_worker;
-	struct kthread_work xmit_work;
-	struct sk_buff_head xmit_queue;
-	struct sja1105_tagger_data *data;
-	bool hwts_tx_en;
-};
-
-/* Timestamps are in units of 8 ns clock ticks (equivalent to
- * a fixed 125 MHz clock).
- */
-#define SJA1105_TICK_NS			8
-
-static inline s64 ns_to_sja1105_ticks(s64 ns)
+static inline struct sja1105_tagger_data *
+sja1105_tagger_data(struct dsa_switch *ds)
 {
-	return ns / SJA1105_TICK_NS;
-}
+	BUG_ON(ds->dst->tag_ops->proto != DSA_TAG_PROTO_SJA1105);
 
-static inline s64 sja1105_ticks_to_ns(s64 ticks)
-{
-	return ticks * SJA1105_TICK_NS;
-}
-
-static inline bool dsa_port_is_sja1105(struct dsa_port *dp)
-{
-	return true;
+	return ds->tagger_data;
 }
 
 #endif /* _NET_DSA_SJA1105_H */