kernel/linux.git/include/net/dsa.h, branch v5.6.11

net: dsa: Get information about stacked DSA protocol

2020-01-09T00:01:13+00:00

It is possible to stack multiple DSA switches in a way that they are not part of the tree (disjoint) but the DSA master of a switch is a DSA slave of another. When that happens switch drivers may have to know this is the case so as to determine whether their tagging protocol has a remove chance of working. This is useful for specific switch drivers such as b53 where devices have been known to be stacked in the wild without the Broadcom tag protocol supporting that feature. This allows b53 to continue supporting those devices by forcing the disabling of Broadcom tags on the outermost switches if necessary. The get_tag_protocol() function is therefore updated to gain an additional enum dsa_tag_protocol argument which denotes the current tagging protocol used by the DSA master we are attached to, else DSA_TAG_PROTO_NONE for the top of the dsa_switch_tree. Signed-off-by: Florian Fainelli Signed-off-by: David S. Miller

net: dsa: Pass pcs_poll flag from driver to PHYLINK

2020-01-06T07:22:32+00:00

The DSA drivers that implement .phylink_mac_link_state should normally register an interrupt for the PCS, from which they should call phylink_mac_change(). However not all switches implement this, and those who don't should set this flag in dsa_switch in the .setup callback, so that PHYLINK will poll for a few ms until the in-band AN link timer expires and the PCS state settles. Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller

net: dsa: Make deferred_xmit private to sja1105

2020-01-05T23:13:13+00:00

There are 3 things that are wrong with the DSA deferred xmit mechanism: 1. Its introduction has made the DSA hotpath ever so slightly more inefficient for everybody, since DSA_SKB_CB(skb)->deferred_xmit needs to be initialized to false for every transmitted frame, in order to figure out whether the driver requested deferral or not (a very rare occasion, rare even for the only driver that does use this mechanism: sja1105). That was necessary to avoid kfree_skb from freeing the skb. 2. Because L2 PTP is a link-local protocol like STP, it requires management routes and deferred xmit with this switch. But as opposed to STP, the deferred work mechanism needs to schedule the packet rather quickly for the TX timstamp to be collected in time and sent to user space. But there is no provision for controlling the scheduling priority of this deferred xmit workqueue. Too bad this is a rather specific requirement for a feature that nobody else uses (more below). 3. Perhaps most importantly, it makes the DSA core adhere a bit too much to the NXP company-wide policy "Innovate Where It Doesn't Matter". The sja1105 is probably the only DSA switch that requires some frames sent from the CPU to be routed to the slave port via an out-of-band configuration (register write) rather than in-band (DSA tag). And there are indeed very good reasons to not want to do that: if that out-of-band register is at the other end of a slow bus such as SPI, then you limit that Ethernet flow's throughput to effectively the throughput of the SPI bus. So hardware vendors should definitely not be encouraged to design this way. We do _not_ want more widespread use of this mechanism. Luckily we have a solution for each of the 3 issues: For 1, we can just remove that variable in the skb->cb and counteract the effect of kfree_skb with skb_get, much to the same effect. The advantage, of course, being that anybody who doesn't use deferred xmit doesn't need to do any extra operation in the hotpath. For 2, we can create a kernel thread for each port's deferred xmit work. If the user switch ports are named swp0, swp1, swp2, the kernel threads will be named swp0_xmit, swp1_xmit, swp2_xmit (there appears to be a 15 character length limit on kernel thread names). With this, the user can change the scheduling priority with chrt $(pidof swp2_xmit). For 3, we can actually move the entire implementation to the sja1105 driver. So this patch deletes the generic implementation from the DSA core and adds a new one, more adequate to the requirements of PTP TX timestamping, in sja1105_main.c. Suggested-by: Florian Fainelli Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller

net: dsa: add support for Atheros AR9331 TAG format

2019-12-21T01:05:47+00:00

Add support for tag format used in Atheros AR9331 built-in switch. Reviewed-by: Vivien Didelot Reviewed-by: Andrew Lunn Signed-off-by: Oleksij Rempel Signed-off-by: David S. Miller

net: dsa: ocelot: add tagger for Ocelot/Felix switches

2019-11-15T20:32:16+00:00

While it is entirely possible that this tagger format is in fact more generic than just these 2 switch families, I don't have that knowledge. The Seville switch in NXP T1040 has a similar frame format, but there are enough differences (e.g. DEST field starts at bit 57 instead of 56) that calling this file tag_vitesse.c is a bit of a stretch at the moment. The frame format has been listed in a comment so that people who add support for further Vitesse switches can rework this tagger while keeping compatibility with Felix. The "ocelot" name was chosen instead of "felix" because even the Ocelot switch can act as a DSA device when it is used in NPI mode, and the Felix tagger format is almost identical. Currently it is only used for the Felix switch embedded in the NXP LS1028A chip. The ABI for this tagger should be considered "not stable" at the moment. The DSA tag is always placed before the Ethernet header and therefore, we are using the long prefix for RX tags to avoid putting the DSA master port in promiscuous mode. Once there will be an API in DSA for drivers to request DSA masters to be in promiscuous mode unconditionally, we will switch to the "no prefix" extraction frame header, which will save 16 padding bytes for each RX frame. Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller

net: dsa: Add support for devlink resources

2019-11-06T02:09:45+00:00

Add wrappers around the devlink resource API, so that DSA drivers can register and unregister devlink resources. Signed-off-by: Andrew Lunn Acked-by: Jiri Pirko Signed-off-by: David S. Miller

net: dsa: remove the dst->ds array

2019-10-31T21:26:38+00:00

Now that the DSA ports are listed in the switch fabric, there is no need to store the dsa_switch structures from the drivers in the fabric anymore. So get rid of the dst->ds static array. Signed-off-by: Vivien Didelot Signed-off-by: David S. Miller

net: dsa: remove ds->rtable

2019-10-31T21:26:38+00:00

Drivers do not use the ds->rtable static arrays anymore, get rid of it. Signed-off-by: Vivien Didelot Signed-off-by: David S. Miller

net: dsa: list DSA links in the fabric

2019-10-31T21:26:38+00:00

Implement a new list of DSA links in the switch fabric itself, to provide an alterative to the ds->rtable static arrays. At the same time, provide a new dsa_routing_port() helper to abstract the usage of ds->rtable in drivers. If there's no port to reach a given device, return the first invalid port, ds->num_ports. This avoids potential signedness errors or the need to define special values. Signed-off-by: Vivien Didelot Signed-off-by: David S. Miller

net: dsa: return directly from dsa_to_port

2019-10-29T19:07:49+00:00

Return directly from within the loop as soon as the port is found, otherwise we won't return NULL if the end of the list is reached. Fixes: b96ddf254b09 ("net: dsa: use ports list in dsa_to_port") Signed-off-by: Vivien Didelot Reviewed-by: Andrew Lunn Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller