From 35d976802124303a5b3eb7ec3ed188d568204373 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Fri, 10 Dec 2021 01:34:38 +0200 Subject: net: dsa: tag_ocelot: convert to tagger-owned data The felix driver makes very light use of dp->priv, and the tagger is effectively stateless. dp->priv is practically only needed to set up a callback to perform deferred xmit of PTP and STP packets using the ocelot-8021q tagging protocol (the main ocelot tagging protocol makes no use of dp->priv, although this driver sets up dp->priv irrespective of actual tagging protocol in use). struct felix_port (what used to be pointed to by dp->priv) is removed and replaced with a two-sided structure. The public side of this structure, visible to the switch driver, is ocelot_8021q_tagger_data. The private side is ocelot_8021q_tagger_private, and the latter structure physically encapsulates the former. The public half of the tagger data structure can be accessed through a helper of the same name (ocelot_8021q_tagger_data) which also sanity-checks the protocol currently in use by the switch. The public/private split was requested by Andrew Lunn. Suggested-by: Andrew Lunn Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller --- include/linux/dsa/ocelot.h | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'include/linux') 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 #include #include +#include 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); -- cgit v1.2.3 From d38049bbe7601f38d598f5da5ff09980483b290a Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Fri, 10 Dec 2021 01:34:40 +0200 Subject: net: dsa: sja1105: bring deferred xmit implementation in line with ocelot-8021q When the ocelot-8021q driver was converted to deferred xmit as part of commit 8d5f7954b7c8 ("net: dsa: felix: break at first CPU port during init and teardown"), the deferred implementation was deliberately made subtly different from what sja1105 has. The implementation differences lied on the following observations: - There might be a race between these two lines in tag_sja1105.c: skb_queue_tail(&sp->xmit_queue, skb_get(skb)); kthread_queue_work(sp->xmit_worker, &sp->xmit_work); and the skb dequeue logic in sja1105_port_deferred_xmit(). For example, the xmit_work might be already queued, however the work item has just finished walking through the skb queue. Because we don't check the return code from kthread_queue_work, we don't do anything if the work item is already queued. However, nobody will take that skb and send it, at least until the next timestampable skb is sent. This creates additional (and avoidable) TX timestamping latency. To close that race, what the ocelot-8021q driver does is it doesn't keep a single work item per port, and a skb timestamping queue, but rather dynamically allocates a work item per packet. - It is also unnecessary to have more than one kthread that does the work. So delete the per-port kthread allocations and replace them with a single kthread which is global to the switch. This change brings the two implementations in line by applying those observations to the sja1105 driver as well. Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller --- include/linux/dsa/sja1105.h | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/dsa/sja1105.h b/include/linux/dsa/sja1105.h index e6c78be40bde..acd9d2afccab 100644 --- a/include/linux/dsa/sja1105.h +++ b/include/linux/dsa/sja1105.h @@ -37,6 +37,12 @@ #define SJA1105_HWTS_RX_EN 0 +struct sja1105_deferred_xmit_work { + struct dsa_port *dp; + struct sk_buff *skb; + struct kthread_work work; +}; + /* Global tagger data: each struct sja1105_port has a reference to * the structure defined in struct sja1105_private. */ @@ -52,6 +58,8 @@ struct sja1105_tagger_data { * 2-step TX timestamps */ struct sk_buff_head skb_txtstamp_queue; + struct kthread_worker *xmit_worker; + void (*xmit_work_fn)(struct kthread_work *work); }; struct sja1105_skb_cb { @@ -65,9 +73,6 @@ struct sja1105_skb_cb { ((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; }; -- cgit v1.2.3 From 6f6770ab1ce2b56619264ec6be0b62f05564dcf6 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Fri, 10 Dec 2021 01:34:41 +0200 Subject: net: dsa: sja1105: remove hwts_tx_en from tagger data This tagger property is in fact not used at all by the tagger, only by the switch driver. Therefore it makes sense to be moved to sja1105_private. Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller --- include/linux/dsa/sja1105.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/dsa/sja1105.h b/include/linux/dsa/sja1105.h index acd9d2afccab..32a8a1344cf6 100644 --- a/include/linux/dsa/sja1105.h +++ b/include/linux/dsa/sja1105.h @@ -74,7 +74,6 @@ struct sja1105_skb_cb { struct sja1105_port { struct sja1105_tagger_data *data; - bool hwts_tx_en; }; /* Timestamps are in units of 8 ns clock ticks (equivalent to -- cgit v1.2.3 From bfcf1425222008e7390c0784b0f3bb7b497fccaa Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Fri, 10 Dec 2021 01:34:42 +0200 Subject: net: dsa: sja1105: make dp->priv point directly to sja1105_tagger_data The design of the sja1105 tagger dp->priv is that each port has a separate struct sja1105_port, and the sp->data pointer points to a common struct sja1105_tagger_data. We have removed all per-port members accessible by the tagger, and now only struct sja1105_tagger_data remains. Make dp->priv point directly to this. Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller --- include/linux/dsa/sja1105.h | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) (limited to 'include/linux') diff --git a/include/linux/dsa/sja1105.h b/include/linux/dsa/sja1105.h index 32a8a1344cf6..1dda9cce85d9 100644 --- a/include/linux/dsa/sja1105.h +++ b/include/linux/dsa/sja1105.h @@ -43,9 +43,7 @@ struct sja1105_deferred_xmit_work { struct kthread_work work; }; -/* Global tagger data: each struct sja1105_port has a reference to - * the structure defined in struct sja1105_private. - */ +/* Global tagger data */ struct sja1105_tagger_data { struct sk_buff *stampable_skb; /* Protects concurrent access to the meta state machine @@ -72,10 +70,6 @@ struct sja1105_skb_cb { #define SJA1105_SKB_CB(skb) \ ((struct sja1105_skb_cb *)((skb)->cb)) -struct sja1105_port { - struct sja1105_tagger_data *data; -}; - /* Timestamps are in units of 8 ns clock ticks (equivalent to * a fixed 125 MHz clock). */ -- cgit v1.2.3 From 22ee9f8e4011fb8a6d75dc2f9a43360d4f400235 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Fri, 10 Dec 2021 01:34:43 +0200 Subject: net: dsa: sja1105: move ts_id from sja1105_tagger_data The TX timestamp ID is incremented by the SJA1110 PTP timestamping callback (->port_tx_timestamp) for every packet, when cloning it. It isn't used by the tagger at all, even though it sits inside the struct sja1105_tagger_data. Also, serialization to this structure is currently done through tagger_data->meta_lock, which is a cheap hack because the meta_lock isn't used for anything else on SJA1110 (sja1105_rcv_meta_state_machine isn't called). This change moves ts_id from sja1105_tagger_data to sja1105_private and introduces a dedicated spinlock for it, also in sja1105_private. Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller --- include/linux/dsa/sja1105.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/dsa/sja1105.h b/include/linux/dsa/sja1105.h index 1dda9cce85d9..d8ee53085c09 100644 --- a/include/linux/dsa/sja1105.h +++ b/include/linux/dsa/sja1105.h @@ -51,7 +51,6 @@ struct sja1105_tagger_data { */ spinlock_t meta_lock; unsigned long state; - u8 ts_id; /* Used on SJA1110 where meta frames are generated only for * 2-step TX timestamps */ -- cgit v1.2.3 From c79e84866d2ac637fce921a28288f214e91d662b Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Fri, 10 Dec 2021 01:34:44 +0200 Subject: net: dsa: tag_sja1105: convert to tagger-owned data Currently, struct sja1105_tagger_data is a part of struct sja1105_private, and is used by the sja1105 driver to populate dp->priv. With the movement towards tagger-owned storage, the sja1105 driver should not be the owner of this memory. This change implements the connection between the sja1105 switch driver and its tagging protocol, which means that sja1105_tagger_data no longer stays in dp->priv but in ds->tagger_data, and that the sja1105 driver now only populates the sja1105_port_deferred_xmit callback pointer. The kthread worker is now the responsibility of the tagger. The sja1105 driver also alters the tagger's state some more, especially with regard to the PTP RX timestamping state. This will be fixed up a bit in further changes. Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller --- include/linux/dsa/sja1105.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/dsa/sja1105.h b/include/linux/dsa/sja1105.h index d8ee53085c09..9f7d42cbbc08 100644 --- a/include/linux/dsa/sja1105.h +++ b/include/linux/dsa/sja1105.h @@ -84,9 +84,12 @@ 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) +static inline struct sja1105_tagger_data * +sja1105_tagger_data(struct dsa_switch *ds) { - return true; + BUG_ON(ds->dst->tag_ops->proto != DSA_TAG_PROTO_SJA1105); + + return ds->tagger_data; } #endif /* _NET_DSA_SJA1105_H */ -- cgit v1.2.3 From fcbf979a5b4b5784bfb5647ae6190cd5c2ae595d Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Fri, 10 Dec 2021 01:34:45 +0200 Subject: Revert "net: dsa: move sja1110_process_meta_tstamp inside the tagging protocol driver" This reverts commit 6d709cadfde68dbd12bef12fcced6222226dcb06. The above change was done to avoid calling symbols exported by the switch driver from the tagging protocol driver. With the tagger-owned storage model, we have a new option on our hands, and that is for the switch driver to provide a data consumer handler in the form of a function pointer inside the ->connect_tag_protocol() method. Having a function pointer avoids the problems of the exported symbols approach. By creating a handler for metadata frames holding TX timestamps on SJA1110, we are able to eliminate an skb queue from the tagger data, and replace it with a simple, and stateless, function pointer. This skb queue is now handled exclusively by sja1105_ptp.c, which makes the code easier to follow, as it used to be before the reverted patch. Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller --- include/linux/dsa/sja1105.h | 26 +++++++------------------- 1 file changed, 7 insertions(+), 19 deletions(-) (limited to 'include/linux') diff --git a/include/linux/dsa/sja1105.h b/include/linux/dsa/sja1105.h index 9f7d42cbbc08..d216211b64f8 100644 --- a/include/linux/dsa/sja1105.h +++ b/include/linux/dsa/sja1105.h @@ -37,6 +37,11 @@ #define SJA1105_HWTS_RX_EN 0 +enum sja1110_meta_tstamp { + SJA1110_META_TSTAMP_TX = 0, + SJA1110_META_TSTAMP_RX = 1, +}; + struct sja1105_deferred_xmit_work { struct dsa_port *dp; struct sk_buff *skb; @@ -51,12 +56,10 @@ struct sja1105_tagger_data { */ spinlock_t meta_lock; unsigned long state; - /* Used on SJA1110 where meta frames are generated only for - * 2-step TX timestamps - */ - struct sk_buff_head skb_txtstamp_queue; struct kthread_worker *xmit_worker; 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); }; struct sja1105_skb_cb { @@ -69,21 +72,6 @@ struct sja1105_skb_cb { #define SJA1105_SKB_CB(skb) \ ((struct sja1105_skb_cb *)((skb)->cb)) -/* 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) -{ - return ns / SJA1105_TICK_NS; -} - -static inline s64 sja1105_ticks_to_ns(s64 ticks) -{ - return ticks * SJA1105_TICK_NS; -} - static inline struct sja1105_tagger_data * sja1105_tagger_data(struct dsa_switch *ds) { -- cgit v1.2.3 From 950a419d9de13668f86828394cb242a1f9dece74 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Fri, 10 Dec 2021 01:34:46 +0200 Subject: net: dsa: tag_sja1105: split sja1105_tagger_data into private and public sections The sja1105 driver messes with the tagging protocol's state when PTP RX timestamping is enabled/disabled. This is fundamentally necessary because the tagger needs to know what to do when it receives a PTP packet. If RX timestamping is enabled, then a metadata follow-up frame is expected, and this holds the (partial) timestamp. So the tagger plays hide-and-seek with the network stack until it also gets the metadata frame, and then presents a single packet, the timestamped PTP packet. But when RX timestamping isn't enabled, there is no metadata frame expected, so the hide-and-seek game must be turned off and the packet must be delivered right away to the network stack. Considering this, we create a pseudo isolation by devising two tagger methods callable by the switch: one to get the RX timestamping state, and one to set it. Since we can't export symbols between the tagger and the switch driver, these methods are exposed through function pointers. After this change, the public portion of the sja1105_tagger_data contains only function pointers. Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller --- include/linux/dsa/sja1105.h | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-) (limited to 'include/linux') diff --git a/include/linux/dsa/sja1105.h b/include/linux/dsa/sja1105.h index d216211b64f8..e9cb1ae6d742 100644 --- a/include/linux/dsa/sja1105.h +++ b/include/linux/dsa/sja1105.h @@ -35,8 +35,6 @@ #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, @@ -50,16 +48,13 @@ struct sja1105_deferred_xmit_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; - struct kthread_worker *xmit_worker; + /* 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 { -- cgit v1.2.3