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The driver was incorrectly converted assuming that "sja1105" is the only
tagger supported by this driver. This results in SJA1110 switches
failing to probe:
sja1105 spi1.0: Unable to connect to tag protocol "sja1110": -EPROTONOSUPPORT
sja1105: probe of spi1.2 failed with error -93
Add DSA_TAG_PROTO_SJA1110 to the list of supported taggers by the
sja1105 driver. The sja1105_tagger_data structure format is common for
the two tagging protocols.
Fixes: c79e84866d2a ("net: dsa: tag_sja1105: convert to tagger-owned data")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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It's nice to be able to test a tagging protocol with dsa_loop, but not
at the cost of losing the ability of building the tagging protocol and
switch driver as modules, because as things stand, there is a circular
dependency between the two. Tagging protocol drivers cannot depend on
switch drivers, that is a hard fact.
The reasoning behind the blamed patch was that accessing dp->priv should
first make sure that the structure behind that pointer is what we really
think it is.
Currently the "sja1105" and "sja1110" tagging protocols only operate
with the sja1105 switch driver, just like any other tagging protocol and
switch combination. The only way to mix and match them is by modifying
the code, and this applies to dsa_loop as well (by default that uses
DSA_TAG_PROTO_NONE). So while in principle there is an issue, in
practice there isn't one.
Until we extend dsa_loop to allow user space configuration, treat the
problem as a non-issue and just say that DSA ports found by tag_sja1105
are always sja1105 ports, which is in fact true. But keep the
dsa_port_is_sja1105 function so that it's easy to patch it during
testing, and rely on dead code elimination.
Fixes: 994d2cbb08ca ("net: dsa: tag_sja1105: be dsa_loop-safe")
Link: https://lore.kernel.org/netdev/20210908220834.d7gmtnwrorhharna@skbuf/
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The problem is that DSA tagging protocols really must not depend on the
switch driver, because this creates a circular dependency at insmod
time, and the switch driver will effectively not load when the tagging
protocol driver is missing.
The code was structured in the way it was for a reason, though. The DSA
driver-facing API for PTP timestamping relies on the assumption that
two-step TX timestamps are provided by the hardware in an out-of-band
manner, typically by raising an interrupt and making that timestamp
available inside some sort of FIFO which is to be accessed over
SPI/MDIO/etc.
So the API puts .port_txtstamp into dsa_switch_ops, because it is
expected that the switch driver needs to save some state (like put the
skb into a queue until its TX timestamp arrives).
On SJA1110, TX timestamps are provided by the switch as Ethernet
packets, so this makes them be received and processed by the tagging
protocol driver. This in itself is great, because the timestamps are
full 64-bit and do not require reconstruction, and since Ethernet is the
fastest I/O method available to/from the switch, PTP timestamps arrive
very quickly, no matter how bottlenecked the SPI connection is, because
SPI interaction is not needed at all.
DSA's code structure and strict isolation between the tagging protocol
driver and the switch driver break the natural code organization.
When the tagging protocol driver receives a packet which is classified
as a metadata packet containing timestamps, it passes those timestamps
one by one to the switch driver, which then proceeds to compare them
based on the recorded timestamp ID that was generated in .port_txtstamp.
The communication between the tagging protocol and the switch driver is
done through a method exported by the switch driver, sja1110_process_meta_tstamp.
To satisfy build requirements, we force a dependency to build the
tagging protocol driver as a module when the switch driver is a module.
However, as explained in the first paragraph, that causes the circular
dependency.
To solve this, move the skb queue from struct sja1105_private :: struct
sja1105_ptp_data to struct sja1105_private :: struct sja1105_tagger_data.
The latter is a data structure for which hacks have already been put
into place to be able to create persistent storage per switch that is
accessible from the tagging protocol driver (see sja1105_setup_ports).
With the skb queue directly accessible from the tagging protocol driver,
we can now move sja1110_process_meta_tstamp into the tagging driver
itself, and avoid exporting a symbol.
Fixes: 566b18c8b752 ("net: dsa: sja1105: implement TX timestamping for SJA1110")
Link: https://lore.kernel.org/netdev/20210908220834.d7gmtnwrorhharna@skbuf/
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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It looks like this field was never used since its introduction in commit
227d07a07ef1 ("net: dsa: sja1105: Add support for traffic through
standalone ports") remove it.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Introduced in commit 38b5beeae7a4 ("net: dsa: sja1105: prepare tagger
for handling DSA tags and VLAN simultaneously"), the sja1105_xmit_tpid
function solved quite a different problem than our needs are now.
Then, we used best-effort VLAN filtering and we were using the xmit_tpid
to tunnel packets coming from an 8021q upper through the TX VLAN allocated
by tag_8021q to that egress port. The need for a different VLAN protocol
depending on switch revision came from the fact that this in itself was
more of a hack to trick the hardware into accepting tunneled VLANs in
the first place.
Right now, we deny 8021q uppers (see sja1105_prechangeupper). Even if we
supported them again, we would not do that using the same method of
{tunneling the VLAN on egress, retagging the VLAN on ingress} that we
had in the best-effort VLAN filtering mode. It seems rather simpler that
we just allocate a VLAN in the VLAN table that is simply not used by the
bridge at all, or by any other port.
Anyway, I have 2 gripes with the current sja1105_xmit_tpid:
1. When sending packets on behalf of a VLAN-aware bridge (with the new
TX forwarding offload framework) plus untagged (with the tag_8021q
VLAN added by the tagger) packets, we can see that on SJA1105P/Q/R/S
and later (which have a qinq_tpid of ETH_P_8021AD), some packets sent
through the DSA master have a VLAN protocol of 0x8100 and others of
0x88a8. This is strange and there is no reason for it now. If we have
a bridge and are therefore forced to send using that bridge's TPID,
we can as well blend with that bridge's VLAN protocol for all packets.
2. The sja1105_xmit_tpid introduces a dependency on the sja1105 driver,
because it looks inside dp->priv. It is desirable to keep as much
separation between taggers and switch drivers as possible. Now it
doesn't do that anymore.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The sja1105 driver is a bit special in its use of VLAN headers as DSA
tags. This is because in VLAN-aware mode, the VLAN headers use an actual
TPID of 0x8100, which is understood even by the DSA master as an actual
VLAN header.
Furthermore, control packets such as PTP and STP are transmitted with no
VLAN header as a DSA tag, because, depending on switch generation, there
are ways to steer these control packets towards a precise egress port
other than VLAN tags. Transmitting control packets as untagged means
leaving a door open for traffic in general to be transmitted as untagged
from the DSA master, and for it to traverse the switch and exit a random
switch port according to the FDB lookup.
This behavior is a bit out of line with other DSA drivers which have
native support for DSA tagging. There, it is to be expected that the
switch only accepts DSA-tagged packets on its CPU port, dropping
everything that does not match this pattern.
We perhaps rely a bit too much on the switches' hardware dropping on the
CPU port, and place no other restrictions in the kernel data path to
avoid that. For example, sja1105 is also a bit special in that STP/PTP
packets are transmitted using "management routes"
(sja1105_port_deferred_xmit): when sending a link-local packet from the
CPU, we must first write a SPI message to the switch to tell it to
expect a packet towards multicast MAC DA 01-80-c2-00-00-0e, and to route
it towards port 3 when it gets it. This entry expires as soon as it
matches a packet received by the switch, and it needs to be reinstalled
for the next packet etc. All in all quite a ghetto mechanism, but it is
all that the sja1105 switches offer for injecting a control packet.
The driver takes a mutex for serializing control packets and making the
pairs of SPI writes of a management route and its associated skb atomic,
but to be honest, a mutex is only relevant as long as all parties agree
to take it. With the DSA design, it is possible to open an AF_PACKET
socket on the DSA master net device, and blast packets towards
01-80-c2-00-00-0e, and whatever locking the DSA switch driver might use,
it all goes kaput because management routes installed by the driver will
match skbs sent by the DSA master, and not skbs generated by the driver
itself. So they will end up being routed on the wrong port.
So through the lens of that, maybe it would make sense to avoid that
from happening by doing something in the network stack, like: introduce
a new bit in struct sk_buff, like xmit_from_dsa. Then, somewhere around
dev_hard_start_xmit(), introduce the following check:
if (netdev_uses_dsa(dev) && !skb->xmit_from_dsa)
kfree_skb(skb);
Ok, maybe that is a bit drastic, but that would at least prevent a bunch
of problems. For example, right now, even though the majority of DSA
switches drop packets without DSA tags sent by the DSA master (and
therefore the majority of garbage that user space daemons like avahi and
udhcpcd and friends create), it is still conceivable that an aggressive
user space program can open an AF_PACKET socket and inject a spoofed DSA
tag directly on the DSA master. We have no protection against that; the
packet will be understood by the switch and be routed wherever user
space says. Furthermore: there are some DSA switches where we even have
register access over Ethernet, using DSA tags. So even user space
drivers are possible in this way. This is a huge hole.
However, the biggest thing that bothers me is that udhcpcd attempts to
ask for an IP address on all interfaces by default, and with sja1105, it
will attempt to get a valid IP address on both the DSA master as well as
on sja1105 switch ports themselves. So with IP addresses in the same
subnet on multiple interfaces, the routing table will be messed up and
the system will be unusable for traffic until it is configured manually
to not ask for an IP address on the DSA master itself.
It turns out that it is possible to avoid that in the sja1105 driver, at
least very superficially, by requesting the switch to drop VLAN-untagged
packets on the CPU port. With the exception of control packets, all
traffic originated from tag_sja1105.c is already VLAN-tagged, so only
STP and PTP packets need to be converted. For that, we need to uphold
the equivalence between an untagged and a pvid-tagged packet, and to
remember that the CPU port of sja1105 uses a pvid of 4095.
Now that we drop untagged traffic on the CPU port, non-aggressive user
space applications like udhcpcd stop bothering us, and sja1105 effectively
becomes just as vulnerable to the aggressive kind of user space programs
as other DSA switches are (ok, users can also create 8021q uppers on top
of the DSA master in the case of sja1105, but in future patches we can
easily deny that, but it still doesn't change the fact that VLAN-tagged
packets can still be injected over raw sockets).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Add support for tag_sja1105 running on non-sja1105 DSA ports, by making
sure that every time we dereference dp->priv, we check the switch's
dsa_switch_ops (otherwise we access a struct sja1105_port structure that
is in fact something else).
This adds an unconditional build-time dependency between sja1105 being
built as module => tag_sja1105 must also be built as module. This was
there only for PTP before.
Some sane defaults must also take place when not running on sja1105
hardware. These are:
- sja1105_xmit_tpid: the sja1105 driver uses different VLAN protocols
depending on VLAN awareness and switch revision (when an encapsulated
VLAN must be sent). Default to 0x8100.
- sja1105_rcv_meta_state_machine: this aggregates PTP frames with their
metadata timestamp frames. When running on non-sja1105 hardware, don't
do that and accept all frames unmodified.
- sja1105_defer_xmit: calls sja1105_port_deferred_xmit in sja1105_main.c
which writes a management route over SPI. When not running on sja1105
hardware, bypass the SPI write and send the frame as-is.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Simply put, the best-effort VLAN filtering mode relied on VLAN retagging
from a bridge VLAN towards a tag_8021q sub-VLAN in order to be able to
decode the source port in the tagger, but the VLAN retagging
implementation inside the sja1105 chips is not the best and we were
relying on marginal operating conditions.
The most notable limitation of the best-effort VLAN filtering mode is
its incapacity to treat this case properly:
ip link add br0 type bridge vlan_filtering 1
ip link set swp2 master br0
ip link set swp4 master br0
bridge vlan del dev swp4 vid 1
bridge vlan add dev swp4 vid 1 pvid
When sending an untagged packet through swp2, the expectation is for it
to be forwarded to swp4 as egress-tagged (so it will contain VLAN ID 1
on egress). But the switch will send it as egress-untagged.
There was an attempt to fix this here:
https://patchwork.kernel.org/project/netdevbpf/patch/20210407201452.1703261-2-olteanv@gmail.com/
but it failed miserably because it broke PTP RX timestamping, in a way
that cannot be corrected due to hardware issues related to VLAN
retagging.
So with either PTP broken or pushing VLAN headers on egress for untagged
packets being broken, the sad reality is that the best-effort VLAN
filtering code is broken. Delete it.
Note that this means there will be a temporary loss of functionality in
this driver until it is replaced with something better (network stack
RX/TX capability for "mode 2" as described in
Documentation/networking/dsa/sja1105.rst, the "port under VLAN-aware
bridge" case). We simply cannot keep this code until that driver rework
is done, it is super bloated and tangled with tag_8021q.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The TX timestamping procedure for SJA1105 is a bit unconventional
because the transmit procedure itself is unconventional.
Control packets (and therefore PTP as well) are transmitted to a
specific port in SJA1105 using "management routes" which must be written
over SPI to the switch. These are one-shot rules that match by
destination MAC address on traffic coming from the CPU port, and select
the precise destination port for that packet. So to transmit a packet
from NET_TX softirq context, we actually need to defer to a process
context so that we can perform that SPI write before we send the packet.
The DSA master dev_queue_xmit() runs in process context, and we poll
until the switch confirms it took the TX timestamp, then we annotate the
skb clone with that TX timestamp. This is why the sja1105 driver does
not need an skb queue for TX timestamping.
But the SJA1110 is a bit (not much!) more conventional, and you can
request 2-step TX timestamping through the DSA header, as well as give
the switch a cookie (timestamp ID) which it will give back to you when
it has the timestamp. So now we do need a queue for keeping the skb
clones until their TX timestamps become available.
The interesting part is that the metadata frames from SJA1105 haven't
disappeared completely. On SJA1105 they were used as follow-ups which
contained RX timestamps, but on SJA1110 they are actually TX completion
packets, which contain a variable (up to 32) array of timestamps.
Why an array? Because:
- not only is the TX timestamp on the egress port being communicated,
but also the RX timestamp on the CPU port. Nice, but we don't care
about that, so we ignore it.
- because a packet could be multicast to multiple egress ports, each
port takes its own timestamp, and the TX completion packet contains
the individual timestamps on each port.
This is unconventional because switches typically have a timestamping
FIFO and raise an interrupt, but this one doesn't. So the tagger needs
to detect and parse meta frames, and call into the main switch driver,
which pairs the timestamps with the skbs in the TX timestamping queue
which are waiting for one.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The SJA1110 has improved a few things compared to SJA1105:
- To send a control packet from the host port with SJA1105, one needed
to program a one-shot "management route" over SPI. This is no longer
true with SJA1110, you can actually send "in-band control extensions"
in the packets sent by DSA, these are in fact DSA tags which contain
the destination port and switch ID.
- When receiving a control packet from the switch with SJA1105, the
source port and switch ID were written in bytes 3 and 4 of the
destination MAC address of the frame (which was a very poor shot at a
DSA header). If the control packet also had an RX timestamp, that
timestamp was sent in an actual follow-up packet, so there were
reordering concerns on multi-core/multi-queue DSA masters, where the
metadata frame with the RX timestamp might get processed before the
actual packet to which that timestamp belonged (there is no way to
pair a packet to its timestamp other than the order in which they were
received). On SJA1110, this is no longer true, control packets have
the source port, switch ID and timestamp all in the DSA tags.
- Timestamps from the switch were partial: to get a 64-bit timestamp as
required by PTP stacks, one would need to take the partial 24-bit or
32-bit timestamp from the packet, then read the current PTP time very
quickly, and then patch in the high bits of the current PTP time into
the captured partial timestamp, to reconstruct what the full 64-bit
timestamp must have been. That is awful because packet processing is
done in NAPI context, but reading the current PTP time is done over
SPI and therefore needs sleepable context.
But it also aggravated a few things:
- Not only is there a DSA header in SJA1110, but there is a DSA trailer
in fact, too. So DSA needs to be extended to support taggers which
have both a header and a trailer. Very unconventional - my understanding
is that the trailer exists because the timestamps couldn't be prepared
in time for putting them in the header area.
- Like SJA1105, not all packets sent to the CPU have the DSA tag added
to them, only control packets do:
* the ones which match the destination MAC filters/traps in
MAC_FLTRES1 and MAC_FLTRES0
* the ones which match FDB entries which have TRAP or TAKETS bits set
So we could in theory hack something up to request the switch to take
timestamps for all packets that reach the CPU, and those would be
DSA-tagged and contain the source port / switch ID by virtue of the
fact that there needs to be a timestamp trailer provided. BUT:
- The SJA1110 does not parse its own DSA tags in a way that is useful
for routing in cross-chip topologies, a la Marvell. And the sja1105
driver already supports cross-chip bridging from the SJA1105 days.
It does that by automatically setting up the DSA links as VLAN trunks
which contain all the necessary tag_8021q RX VLANs that must be
communicated between the switches that span the same bridge. So when
using tag_8021q on sja1105, it is possible to have 2 switches with
ports sw0p0, sw0p1, sw1p0, sw1p1, and 2 VLAN-unaware bridges br0 and
br1, and br0 can take sw0p0 and sw1p0, and br1 can take sw0p1 and
sw1p1, and forwarding will happen according to the expected rules of
the Linux bridge.
We like that, and we don't want that to go away, so as a matter of
fact, the SJA1110 tagger still needs to support tag_8021q.
So the sja1110 tagger is a hybrid between tag_8021q for data packets,
and the native hardware support for control packets.
On RX, packets have a 13-byte trailer if they contain an RX timestamp.
That trailer is padded in such a way that its byte 8 (the start of the
"residence time" field - not parsed by Linux because we don't care) is
aligned on a 16 byte boundary. So the padding has a variable length
between 0 and 15 bytes. The DSA header contains the offset of the
beginning of the padding relative to the beginning of the frame (and the
end of the padding is obviously the end of the packet minus 13 bytes,
the length of the trailer). So we discard it.
Packets which don't have a trailer contain the source port and switch ID
information in the header (they are "trap-to-host" packets). Packets
which have a trailer contain the source port and switch ID in the trailer.
On TX, the destination port mask and switch ID is always in the trailer,
so we always need to say in the header that a trailer is present.
The header needs a custom EtherType and this was chosen as 0xdadc, after
0xdada which is for Marvell and 0xdadb which is for VLANs in
VLAN-unaware mode on SJA1105 (and SJA1110 in fact too).
Because we use tag_8021q in concert with the native tagging protocol,
control packets will have 2 DSA tags.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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In SJA1105, RX timestamps for packets sent to the CPU are transmitted in
separate follow-up packets (metadata frames). These contain partial
timestamps (24 or 32 bits) which are kept in SJA1105_SKB_CB(skb)->meta_tstamp.
Thankfully, SJA1110 improved that, and the RX timestamps are now
transmitted in-band with the actual packet, in the timestamp trailer.
The RX timestamps are now full-width 64 bits.
Because we process the RX DSA tags in the rcv() method in the tagger,
but we would like to preserve the DSA code structure in that we populate
the skb timestamp in the port_rxtstamp() call which only happens later,
the implication is that we must somehow pass the 64-bit timestamp from
the rcv() method all the way to port_rxtstamp(). We can use the skb->cb
for that.
Rename the meta_tstamp from struct sja1105_skb_cb from "meta_tstamp" to
"tstamp", and increase its size to 64 bits.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Free skb->cb usage in core driver and let device drivers decide to
use or not. The reason having a DSA_SKB_CB(skb)->clone was because
dsa_skb_tx_timestamp() which may set the clone pointer was called
before p->xmit() which would use the clone if any, and the device
driver has no way to initialize the clone pointer.
This patch just put memset(skb->cb, 0, sizeof(skb->cb)) at beginning
of dsa_slave_xmit(). Some new features in the future, like one-step
timestamp may need more bytes of skb->cb to use in
dsa_skb_tx_timestamp(), and p->xmit().
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Create a subvlan_map as part of each port's tagger private structure.
This keeps reverse mappings of bridge-to-dsa_8021q VLAN retagging rules.
Note that as of this patch, this piece of code is never engaged, due to
the fact that the driver hasn't installed any retagging rule, so we'll
always see packets with a subvlan code of 0 (untagged).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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In VLAN-unaware mode, sja1105 uses VLAN tags with a custom TPID of
0xdadb. While in the yet-to-be introduced best_effort_vlan_filtering
mode, it needs to work with normal VLAN TPID values.
A complication arises when we must transmit a VLAN-tagged packet to the
switch when it's in VLAN-aware mode. We need to construct a packet with
2 VLAN tags, and the switch will use the outer header for routing and
pop it on egress. But sadly, here the 2 hardware generations don't
behave the same:
- E/T switches won't pop an ETH_P_8021AD tag on egress, it seems
(packets will remain double-tagged).
- P/Q/R/S switches will drop a packet with 2 ETH_P_8021Q tags (it looks
like it tries to prevent VLAN hopping).
But looks like the reverse is also true:
- E/T switches have no problem popping the outer tag from packets with
2 ETH_P_8021Q tags.
- P/Q/R/S will have no problem popping a single tag even if that is
ETH_P_8021AD.
So it is clear that if we want the hardware to work with dsa_8021q
tagging in VLAN-aware mode, we need to send different TPIDs depending on
revision. Keep that information in priv->info->qinq_tpid.
The per-port tagger structure will hold an xmit_tpid value that depends
not only upon the qinq_tpid, but also upon the VLAN awareness state
itself (in case we must transmit using 0xdadb).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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 <f.fainelli@gmail.com>
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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I finally found out how the 4 management route slots are supposed to
be used, but.. it's not worth it.
The description from the comment I've just deleted in this commit is
still true: when more than 1 management slot is active at the same time,
the switch will match frames incoming [from the CPU port] on the lowest
numbered management slot that matches the frame's DMAC.
My issue was that one was not supposed to statically assign each port a
slot. Yes, there are 4 slots and also 4 non-CPU ports, but that is a
mere coincidence.
Instead, the switch can be used like this: every management frame gets a
slot at the right of the most recently assigned slot:
Send mgmt frame 1 through S0: S0 x x x
Send mgmt frame 2 through S1: S0 S1 x x
Send mgmt frame 3 through S2: S0 S1 S2 x
Send mgmt frame 4 through S3: S0 S1 S2 S3
The difference compared to the old usage is that the transmission of
frames 1-4 doesn't need to wait until the completion of the management
route. It is safe to use a slot to the right of the most recently used
one, because by protocol nobody will program a slot to your left and
"steal" your route towards the correct egress port.
So there is a potential throughput benefit here.
But mgmt frame 5 has no more free slot to use, so it has to wait until
_all_ of S0, S1, S2, S3 are full, in order to use S0 again.
And that's actually exactly the problem: I was looking for something
that would bring more predictable transmission latency, but this is
exactly the opposite: 3 out of 4 frames would be transmitted quicker,
but the 4th would draw the short straw and have a worse worst-case
latency than before.
Useless.
Things are made even worse by PTP TX timestamping, which is something I
won't go deeply into here. Suffice to say that the fact there is a
driver-level lock on the SPI bus offsets any potential throughput gains
that parallelism might bring.
So there's no going back to the multi-slot scheme, remove the
"mgmt_slot" variable from sja1105_port and the dummy static assignment
made at probe time.
While passing by, also remove the assignment to casc_port altogether.
Don't pretend that we support cascaded setups.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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And move the queue of skb's waiting for RX timestamps into the ptp_data
structure, since it isn't needed if PTP is not compiled.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Currently this stack trace can be seen with CONFIG_DEBUG_ATOMIC_SLEEP=y:
[ 41.568348] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:909
[ 41.576757] in_atomic(): 1, irqs_disabled(): 0, pid: 208, name: ptp4l
[ 41.583212] INFO: lockdep is turned off.
[ 41.587123] CPU: 1 PID: 208 Comm: ptp4l Not tainted 5.3.0-rc6-01445-ge950f2d4bc7f-dirty #1827
[ 41.599873] [<c0313d7c>] (unwind_backtrace) from [<c030e13c>] (show_stack+0x10/0x14)
[ 41.607584] [<c030e13c>] (show_stack) from [<c1212d50>] (dump_stack+0xd4/0x100)
[ 41.614863] [<c1212d50>] (dump_stack) from [<c037dfc8>] (___might_sleep+0x1c8/0x2b4)
[ 41.622574] [<c037dfc8>] (___might_sleep) from [<c122ea90>] (__mutex_lock+0x48/0xab8)
[ 41.630368] [<c122ea90>] (__mutex_lock) from [<c122f51c>] (mutex_lock_nested+0x1c/0x24)
[ 41.638340] [<c122f51c>] (mutex_lock_nested) from [<c0c6fe08>] (sja1105_static_config_reload+0x30/0x27c)
[ 41.647779] [<c0c6fe08>] (sja1105_static_config_reload) from [<c0c7015c>] (sja1105_hwtstamp_set+0x108/0x1cc)
[ 41.657562] [<c0c7015c>] (sja1105_hwtstamp_set) from [<c0feb650>] (dev_ifsioc+0x18c/0x330)
[ 41.665788] [<c0feb650>] (dev_ifsioc) from [<c0febbd8>] (dev_ioctl+0x320/0x6e8)
[ 41.673064] [<c0febbd8>] (dev_ioctl) from [<c0f8b1f4>] (sock_ioctl+0x334/0x5e8)
[ 41.680340] [<c0f8b1f4>] (sock_ioctl) from [<c05404a8>] (do_vfs_ioctl+0xb0/0xa10)
[ 41.687789] [<c05404a8>] (do_vfs_ioctl) from [<c0540e3c>] (ksys_ioctl+0x34/0x58)
[ 41.695151] [<c0540e3c>] (ksys_ioctl) from [<c0301000>] (ret_fast_syscall+0x0/0x28)
[ 41.702768] Exception stack(0xe8495fa8 to 0xe8495ff0)
[ 41.707796] 5fa0: beff4a8c 00000001 00000011 000089b0 beff4a8c beff4a80
[ 41.715933] 5fc0: beff4a8c 00000001 0000000c 00000036 b6fa98c8 004e19c1 00000001 00000000
[ 41.724069] 5fe0: 004dcedc beff4a6c 004c0738 b6e7af4c
[ 41.729860] BUG: scheduling while atomic: ptp4l/208/0x00000002
[ 41.735682] INFO: lockdep is turned off.
Enabling RX timestamping will logically disturb the fastpath (processing
of meta frames). Replace bool hwts_rx_en with a bit that is checked
atomically from the fastpath and temporarily unset from the sleepable
context during a change of the RX timestamping process (a destructive
operation anyways, requires switch reset).
If found unset, the fastpath (net/dsa/tag_sja1105.c) will just drop any
received meta frame and not take the meta_lock at all.
Fixes: a602afd200f5 ("net: dsa: sja1105: Expose PTP timestamping ioctls to userspace")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Meta frame reception relies on the hardware keeping its promise that it
will send no other traffic towards the CPU port between a link-local
frame and a meta frame. Otherwise there is no other way to associate
the meta frame with the link-local frame it's holding a timestamp of.
The receive function is made stateful, and buffers a timestampable frame
until its meta frame arrives, then merges the two, drops the meta and
releases the link-local frame up the stack.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This will be used to keep state for RX timestamping. It is global
because the switch serializes timestampable and meta frames when
trapping them towards the CPU port (lower port indices have higher
priority) and therefore having one state machine per port would create
unnecessary complications.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Meta frames are sent on the CPU port by the switch if RX timestamping is
enabled. They contain a partial timestamp of the previous frame.
They are Ethernet frames with the Ethernet header constructed out of:
- SJA1105_META_DMAC
- SJA1105_META_SMAC
- ETH_P_SJA1105_META
The Ethernet payload will be decoded in a follow-up patch.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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On TX, timestamping is performed synchronously from the
port_deferred_xmit worker thread.
In management routes, the switch is requested to take egress timestamps
(again partial), which are reconstructed and appended to a clone of the
skb that was just sent. The cloning is done by DSA and we retrieve the
pointer from the structure that DSA keeps in skb->cb.
Then these clones are enqueued to the socket's error queue for
application-level processing.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Due to a confusion I thought that eth_type_trans() was called by the
network stack whereas it can actually be called by network drivers to
figure out the skb protocol and next packet_type handlers.
In light of the above, it is not safe to store the frame type from the
DSA tagger's .filter callback (first entry point on RX path), since GRO
is yet to be invoked on the received traffic. Hence it is very likely
that the skb->cb will actually get overwritten between eth_type_trans()
and the actual DSA packet_type handler.
Of course, what this patch fixes is the actual overwriting of the
SJA1105_SKB_CB(skb)->type field from the GRO layer, which made all
frames be seen as SJA1105_FRAME_TYPE_NORMAL (0).
Fixes: 227d07a07ef1 ("net: dsa: sja1105: Add support for traffic through standalone ports")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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In order to support this, we are creating a make-shift switch tag out of
a VLAN trunk configured on the CPU port. Termination of normal traffic
on switch ports only works when not under a vlan_filtering bridge.
Termination of management (PTP, BPDU) traffic works under all
circumstances because it uses a different tagging mechanism
(incl_srcpt). We are making use of the generic CONFIG_NET_DSA_TAG_8021Q
code and leveraging it from our own CONFIG_NET_DSA_TAG_SJA1105.
There are two types of traffic: regular and link-local.
The link-local traffic received on the CPU port is trapped from the
switch's regular forwarding decisions because it matched one of the two
DMAC filters for management traffic.
On transmission, the switch requires special massaging for these
link-local frames. Due to a weird implementation of the switching IP, by
default it drops link-local frames that originate on the CPU port.
It needs to be told where to forward them to, through an SPI command
("management route") that is valid for only a single frame.
So when we're sending link-local traffic, we are using the
dsa_defer_xmit mechanism.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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VLAN filtering cannot be properly disabled in SJA1105. So in order to
emulate the "no VLAN awareness" behavior (not dropping traffic that is
tagged with a VID that isn't configured on the port), we need to hack
another switch feature: programmable TPID (which is 0x8100 for 802.1Q).
We are reprogramming the TPID to a bogus value which leaves the switch
thinking that all traffic is untagged, and therefore accepts it.
Under a vlan_filtering bridge, the proper TPID of ETH_P_8021Q is
installed again, and the switch starts identifying 802.1Q-tagged
traffic.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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At this moment the following is supported:
* Link state management through phylib
* Autonomous L2 forwarding managed through iproute2 bridge commands.
IP termination must be done currently through the master netdevice,
since the switch is unmanaged at this point and using
DSA_TAG_PROTO_NONE.
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Georg Waibel <georg.waibel@sensor-technik.de>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Vladimir Oltean
Yangbo Lu
Vladimir Oltean