| Age | Commit message (Collapse) | Author |
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With this port schedule:
tc qdisc replace dev $send_if parent root handle 100 taprio \
num_tc 8 queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 \
map 0 1 2 3 4 5 6 7 \
base-time 0 cycle-time 10000 \
sched-entry S 01 1250 \
sched-entry S 02 1250 \
sched-entry S 04 1250 \
sched-entry S 08 1250 \
sched-entry S 10 1250 \
sched-entry S 20 1250 \
sched-entry S 40 1250 \
sched-entry S 80 1250 \
flags 2
ptp4l would fail to take TX timestamps of Pdelay_Resp messages like this:
increasing tx_timestamp_timeout may correct this issue, but it is likely caused by a driver bug
ptp4l[4134.168]: port 2: send peer delay response failed
It turns out that the driver can't take their TX timestamps because it
can't transmit them in the first place. And there's nothing special
about the Pdelay_Resp packets - they're just regular 68 byte packets.
But with this taprio configuration, the switch would refuse to send even
the ETH_ZLEN minimum packet size.
This should have definitely not been the case. When applying the taprio
config, the driver prints:
mscc_felix 0000:00:00.5: port 0 tc 0 min gate length 1250 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 132 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 1 min gate length 1250 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 132 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 2 min gate length 1250 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 132 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 3 min gate length 1250 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 132 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 4 min gate length 1250 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 132 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 5 min gate length 1250 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 132 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 6 min gate length 1250 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 132 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 7 min gate length 1250 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 132 octets including FCS
and thus, everything under 132 bytes - ETH_FCS_LEN should have been sent
without problems. Yet it's not.
For the forwarding path, the configuration is fine, yet packets injected
from Linux get stuck with this schedule no matter what.
The first hint that the static guard bands are the cause of the problem
is that reverting Michael Walle's commit 297c4de6f780 ("net: dsa: felix:
re-enable TAS guard band mode") made things work. It must be that the
guard bands are calculated incorrectly.
I remembered that there is a magic constant in the driver, set to 33 ns
for no logical reason other than experimentation, which says "never let
the static guard bands get so large as to leave less than this amount of
remaining space in the time slot, because the queue system will refuse
to schedule packets otherwise, and they will get stuck". I had a hunch
that my previous experimentally-determined value was only good for
packets coming from the forwarding path, and that the CPU injection path
needed more.
I came to the new value of 35 ns through binary search, after seeing
that with 544 ns (the bit time required to send the Pdelay_Resp packet
at gigabit) it works. Again, this is purely experimental, there's no
logic and the manual doesn't say anything.
The new driver prints for this schedule look like this:
mscc_felix 0000:00:00.5: port 0 tc 0 min gate length 1250 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 131 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 1 min gate length 1250 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 131 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 2 min gate length 1250 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 131 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 3 min gate length 1250 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 131 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 4 min gate length 1250 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 131 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 5 min gate length 1250 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 131 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 6 min gate length 1250 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 131 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 7 min gate length 1250 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 131 octets including FCS
So yes, the maximum MTU is now even smaller by 1 byte than before.
This is maybe counter-intuitive, but makes more sense with a diagram of
one time slot.
Before:
Gate open Gate close
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v 1250 ns total time slot duration v
<---------------------------------------------------->
<----><---------------------------------------------->
33 ns 1217 ns static guard band
useful
Gate open Gate close
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v 1250 ns total time slot duration v
<---------------------------------------------------->
<-----><--------------------------------------------->
35 ns 1215 ns static guard band
useful
The static guard band implemented by this switch hardware directly
determines the maximum allowable MTU for that traffic class. The larger
it is, the earlier the switch will stop scheduling frames for
transmission, because otherwise they might overrun the gate close time
(and avoiding that is the entire purpose of Michael's patch).
So, we now have guard bands smaller by 2 ns, thus, in this particular
case, we lose a byte of the maximum MTU.
Fixes: 11afdc6526de ("net: dsa: felix: tc-taprio intervals smaller than MTU should send at least one packet")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Michael Walle <mwalle@kernel.org>
Link: https://patch.msgid.link/20241210132640.3426788-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Cross-merge networking fixes after downstream PR.
No conflicts (sort of) and no adjacent changes.
This merge reverts commit b3c9e65eb227 ("net: hsr: remove seqnr_lock")
from net, as it was superseded by
commit 430d67bdcb04 ("net: hsr: Use the seqnr lock for frames received via interlink port.")
in net-next.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The TAS module could not be configured when it's running in pending
status. We need disable the module and configure it again. However, the
pending status is not cleared after the module disabled. TC taprio set
will always return busy even it's disabled.
For example, a user uses tc-taprio to configure Qbv and a future
basetime. The TAS module will run in a pending status. There is no way
to reconfigure Qbv, it always returns busy.
Actually the TAS module can be reconfigured when it's disabled. So it
doesn't need to check the pending status if the TAS module is disabled.
After the patch, user can delete the tc taprio configuration to disable
Qbv and reconfigure it again.
Fixes: de143c0e274b ("net: dsa: felix: Configure Time-Aware Scheduler via taprio offload")
Signed-off-by: Xiaoliang Yang <xiaoliang.yang_1@nxp.com>
Link: https://patch.msgid.link/20240906093550.29985-1-xiaoliang.yang_1@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Add the __counted_by compiler attribute to the flexible array member
entries to improve access bounds-checking via CONFIG_UBSAN_BOUNDS and
CONFIG_FORTIFY_SOURCE.
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Link: https://patch.msgid.link/20240904014956.2035117-1-lihongbo22@huawei.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Russell King suggested that felix_vsc9959, seville_vsc9953 and
ocelot_ext have a large portion of duplicated init code, which could be
made common [1].
[1]: https://lore.kernel.org/all/Zh1GvcOTXqb7CpQt@shell.armlinux.org.uk/
Here, we take the following common steps:
- "felix" and "ds" structure allocation
- "felix", "ocelot" and "ds" basic structure initialization
- dsa_register_switch() call
and we make a common function out of them.
For every driver except felix_vsc9959, this is also the entire probing
procedure. For felix_vsc9959, we also need to do some PCI-specific
stuff, which can easily be reordered to be done before, and unwound on
failure.
We also have to convert the bus-specific platform_set_drvdata() and
pci_set_drvdata() calls into dev_set_drvdata(). But this should have no
impact on the behavior.
Suggested-by: "Russell King (Oracle)" <linux@armlinux.org.uk>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Colin Foster <colin.foster@in-advantage.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Russell King points out that seville_vsc9953 populates
felix->info->num_tx_queues = 8, but this doesn't make it all the way
into ds->num_tx_queues (which is how the user interface netdev queues
get allocated) [1].
[1]: https://lore.kernel.org/all/20240415160150.yejcazpjqvn7vhxu@skbuf/
When num_tx_queues=0 for seville, this is implicitly converted to 1 by
dsa_user_create(), and this is good enough for basic operation for a
switch port. The tc qdisc offload layer works with netdev TX queues,
so for QoS offload we need to pretend we have multiple TX queues. The
VSC9953, like ocelot_ext, doesn't export QoS offload, so it doesn't
really matter. But we can definitely set num_tx_queues=8 for all
switches.
The felix->info->num_tx_queues construct itself seems unnecessary.
It was introduced by commit de143c0e274b ("net: dsa: felix: Configure
Time-Aware Scheduler via taprio offload") at a time when vsc9959
(LS1028A) was the only switch supported by the driver.
8 traffic classes, and 1 queue per traffic class, is a common
architectural feature of all switches in the family. So they could
all just set OCELOT_NUM_TC and be fine.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Colin Foster <colin.foster@in-advantage.com>
Tested-by: Colin Foster <colin.foster@in-advantage.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The current placement of devm_request_threaded_irq() is inconvenient.
It is between the allocation of the "felix" structure and
dsa_register_switch(), both of which we'd like to refactor into a
function that's common for all switches. But the IRQ is specific to
felix_vsc9959.
A closer inspection of the felix_irq_handler() code suggests that
it does things that depend on the data structures having been fully
initialized. For example, ocelot_get_txtstamp() takes
&port->tx_skbs.lock, which has only been initialized in
ocelot_init_port() which has not run yet.
It is not one of those IRQF_SHARED IRQs, so CONFIG_DEBUG_SHIRQ_FIXME
shouldn't apply here, and thus, it doesn't really matter, because in
practice, the IRQ will not be triggered so early. Nonetheless, it is a
good practice for the driver to be prepared for it to fire as soon as it
is requested.
Create a new felix->info method for running custom code for vsc9959 from
within felix_setup(), and move the request_irq() call there. The
ocelot_ext should have an IRQ as well, so this should be a step in the
right direction for that model (VSC7512) as well.
Some minor changes are made while moving the code. Casts from void *
aren't necessary, so drop them, and rename felix_irq_handler() to the
more specific vsc9959_irq_handler().
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Russell King suggested that felix_vsc9959, seville_vsc9953 and
ocelot_ext have a large portion of duplicated init and teardown code,
which could be made common [1]. The teardown code could even be
simplified away if we made use of devres, something which is used here
and there in the felix driver, just not very consistently.
[1] https://lore.kernel.org/all/Zh1GvcOTXqb7CpQt@shell.armlinux.org.uk/
Prepare the ground in the felix_vsc9959 driver, by allocating the data
structures using devres and deleting the kfree() calls. This also
deletes the "Failed to allocate ..." message, since memory allocation
errors are extremely loud anyway, and it's hard to miss them.
Suggested-by: "Russell King (Oracle)" <linux@armlinux.org.uk>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Since commit 6fffbc7ae137 ("PCI: Honor firmware's device disabled
status"), PCI device drivers with OF bindings no longer need this check.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Convert felix to provide its own phylink MAC operations, thus
avoiding the shim layer in DSA's port.c.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/E1sByYA-00EM0y-Jn@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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This driver currently doesn't support any control flags.
Use flow_rule_match_has_control_flags() to check for control flags,
such as can be set through `tc flower ... ip_flags frag`.
In case any control flags are masked, flow_rule_match_has_control_flags()
sets a NL extended error message, and we return -EOPNOTSUPP.
Only compile-tested.
Signed-off-by: Asbjørn Sloth Tønnesen <ast@fiberby.net>
Link: https://lore.kernel.org/r/20240417144407.104241-1-ast@fiberby.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Cross-merge networking fixes after downstream PR.
Conflicts:
include/net/inet_sock.h
f866fbc842de ("ipv4: fix data-races around inet->inet_id")
c274af224269 ("inet: introduce inet->inet_flags")
https://lore.kernel.org/all/679ddff6-db6e-4ff6-b177-574e90d0103d@tessares.net/
Adjacent changes:
drivers/net/bonding/bond_alb.c
e74216b8def3 ("bonding: fix macvlan over alb bond support")
f11e5bd159b0 ("bonding: support balance-alb with openvswitch")
drivers/net/ethernet/broadcom/bgmac.c
d6499f0b7c7c ("net: bgmac: Return PTR_ERR() for fixed_phy_register()")
23a14488ea58 ("net: bgmac: Fix return value check for fixed_phy_register()")
drivers/net/ethernet/broadcom/genet/bcmmii.c
32bbe64a1386 ("net: bcmgenet: Fix return value check for fixed_phy_register()")
acf50d1adbf4 ("net: bcmgenet: Return PTR_ERR() for fixed_phy_register()")
net/sctp/socket.c
f866fbc842de ("ipv4: fix data-races around inet->inet_id")
b09bde5c3554 ("inet: move inet->mc_loop to inet->inet_frags")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The blamed commit resolved a bug where frames would still get stuck at
egress, even though they're smaller than the maxSDU[tc], because the
driver did not take into account the extra 33 ns that the queue system
needs for scheduling the frame.
It now takes that into account, but the arithmetic that we perform in
vsc9959_tas_remaining_gate_len_ps() is buggy, because we operate on
64-bit unsigned integers, so gate_len_ns - VSC9959_TAS_MIN_GATE_LEN_NS
may become a very large integer if gate_len_ns < 33 ns.
In practice, this means that we've introduced a regression where all
traffic class gates which are permanently closed will not get detected
by the driver, and we won't enable oversize frame dropping for them.
Before:
mscc_felix 0000:00:00.5: port 0: max frame size 1526 needs 12400000 ps, 1152000 ps for mPackets at speed 1000
mscc_felix 0000:00:00.5: port 0 tc 0 min gate len 1000000, sending all frames
mscc_felix 0000:00:00.5: port 0 tc 1 min gate len 0, sending all frames
mscc_felix 0000:00:00.5: port 0 tc 2 min gate len 0, sending all frames
mscc_felix 0000:00:00.5: port 0 tc 3 min gate len 0, sending all frames
mscc_felix 0000:00:00.5: port 0 tc 4 min gate len 0, sending all frames
mscc_felix 0000:00:00.5: port 0 tc 5 min gate len 0, sending all frames
mscc_felix 0000:00:00.5: port 0 tc 6 min gate len 0, sending all frames
mscc_felix 0000:00:00.5: port 0 tc 7 min gate length 5120 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 615 octets including FCS
After:
mscc_felix 0000:00:00.5: port 0: max frame size 1526 needs 12400000 ps, 1152000 ps for mPackets at speed 1000
mscc_felix 0000:00:00.5: port 0 tc 0 min gate len 1000000, sending all frames
mscc_felix 0000:00:00.5: port 0 tc 1 min gate length 0 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 1 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 2 min gate length 0 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 1 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 3 min gate length 0 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 1 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 4 min gate length 0 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 1 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 5 min gate length 0 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 1 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 6 min gate length 0 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 1 octets including FCS
mscc_felix 0000:00:00.5: port 0 tc 7 min gate length 5120 ns not enough for max frame size 1526 at 1000 Mbps, dropping frames over 615 octets including FCS
Fixes: 11afdc6526de ("net: dsa: felix: tc-taprio intervals smaller than MTU should send at least one packet")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20230817120111.3522827-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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As 32bits of dissector->used_keys are exhausted,
increase the size to 64bits.
This is base change for ESP/AH flow dissector patch.
Please find patch and discussions at
https://lore.kernel.org/netdev/ZMDNjD46BvZ5zp5I@corigine.com/T/#t
Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>
Reviewed-by: Petr Machata <petrm@nvidia.com> # for mlxsw
Tested-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Martin Habets <habetsm.xilinx@gmail.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20230724211859.805481-1-robh@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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This switch implements Hold/Release in a strange way, with no control
from the user as required by IEEE 802.1Q-2018 through Set-And-Hold-MAC
and Set-And-Release-MAC, but rather, it emits HOLD requests implicitly
based on the schedule.
Namely, when the gate of a preemptible TC is about to close (actually
QSYS::PREEMPTION_CFG.HOLD_ADVANCE octet times in advance of this event),
the QSYS seems to emit a HOLD request pulse towards the MAC which
preempts the currently transmitted packet, and further packets are held
back in the queue system.
This allows large frames to be squeezed through small time slots,
because HOLD requests initiated by the gate events result in the frame
being segmented in multiple fragments, the bit time of which is equal to
the size of the time slot.
It has been reported that the vsc9959_tas_guard_bands_update() logic
breaks this, because it doesn't take preemptible TCs into account, and
enables oversized frame dropping when the time slot doesn't allow a full
MTU to be sent, but it does allow 2*minFragSize to be sent (128B).
Packets larger than 128B are dropped instead of being sent in multiple
fragments.
Confusingly, the manual says:
| For guard band, SDU calculation of a traffic class of a port, if
| preemption is enabled (through 'QSYS::PREEMPTION_CFG.P_QUEUES') then
| QSYS::PREEMPTION_CFG.HOLD_ADVANCE is used, otherwise
| QSYS::QMAXSDU_CFG_*.QMAXSDU_* is used.
but this only refers to the static guard band durations, and the
QMAXSDU_CFG_* registers have dual purpose - the other being oversized
frame dropping, which takes place irrespective of whether frames are
preemptible or express.
So, to fix the problem, we need to call vsc9959_tas_guard_bands_update()
from ocelot_port_update_active_preemptible_tcs(), and modify the guard
band logic to consider a different (lower) oversize limit for
preemptible traffic classes.
Fixes: 403ffc2c34de ("net: mscc: ocelot: add support for preemptible traffic classes")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Message-ID: <20230705104422.49025-4-vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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In a future change we will need to make
ocelot_port_update_active_preemptible_tcs() call
vsc9959_tas_guard_bands_update(), but that is currently not possible,
since the ocelot switch lib does not have access to functions private to
the DSA wrapper.
Move the pointer to vsc9959_tas_guard_bands_update() from felix->info
(which is private to the DSA driver) to ocelot->ops (which is also
visible to the ocelot switch lib).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Message-ID: <20230705104422.49025-3-vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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In a future commit we will have to call vsc9959_tas_guard_bands_update()
from ocelot_port_update_active_preemptible_tcs(), and that will be
impossible due to the AB/BA locking dependencies between
ocelot->tas_lock and ocelot->fwd_domain_lock.
Just like we did in commit 3ff468ef987e ("net: mscc: ocelot: remove
struct ocelot_mm_state :: lock"), the only solution is to expand the
scope of ocelot->fwd_domain_lock for it to also serialize changes made
to the Time-Aware Shaper, because those will have to result in a
recalculation of cut-through TCs, which is something that depends on the
forwarding domain.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Message-ID: <20230705104422.49025-2-vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Cross-merge networking fixes after downstream PR.
Conflicts:
include/linux/mlx5/driver.h
617f5db1a626 ("RDMA/mlx5: Fix affinity assignment")
dc13180824b7 ("net/mlx5: Enable devlink port for embedded cpu VF vports")
https://lore.kernel.org/all/20230613125939.595e50b8@canb.auug.org.au/
tools/testing/selftests/net/mptcp/mptcp_join.sh
47867f0a7e83 ("selftests: mptcp: join: skip check if MIB counter not supported")
425ba803124b ("selftests: mptcp: join: support RM_ADDR for used endpoints or not")
45b1a1227a7a ("mptcp: introduces more address related mibs")
0639fa230a21 ("selftests: mptcp: add explicit check for new mibs")
https://lore.kernel.org/netdev/20230609-upstream-net-20230610-mptcp-selftests-support-old-kernels-part-3-v1-0-2896fe2ee8a3@tessares.net/
No adjacent changes.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The DEV_MAC_MAXLEN_CFG register contains a 16-bit value - up to 65535.
Plus 2 * VLAN_HLEN (4), that is up to 65543.
The picos_per_byte variable is the largest when "speed" is lowest -
SPEED_10 = 10. In that case it is (1000000L * 8) / 10 = 800000.
Their product - 52434400000 - exceeds 32 bits, which is a problem,
because apparently, a multiplication between two 32-bit factors is
evaluated as 32-bit before being assigned to a 64-bit variable.
In fact it's a problem for any MTU value larger than 5368.
Cast one of the factors of the multiplication to u64 to force the
multiplication to take place on 64 bits.
Issue found by Coverity.
Fixes: 55a515b1f5a9 ("net: dsa: felix: drop oversized frames with tc-taprio instead of hanging the port")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20230613170907.2413559-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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This error path needs call mutex_unlock(&ocelot->tas_lock) before
returning.
Fixes: 2d800bc500fb ("net/sched: taprio: replace tc_taprio_qopt_offload :: enable with a "cmd" enum")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Inspired from struct flow_cls_offload :: cmd, in order for taprio to be
able to report statistics (which is future work), it seems that we need
to drill one step further with the ndo_setup_tc(TC_SETUP_QDISC_TAPRIO)
multiplexing, and pass the command as part of the common portion of the
muxed structure.
Since we already have an "enable" variable in tc_taprio_qopt_offload,
refactor all drivers to check for "cmd" instead of "enable", and reject
every other command except "replace" and "destroy" - to be future proof.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Horatiu Vultur <horatiu.vultur@microchip.com> # for lan966x
Acked-by: Kurt Kanzenbach <kurt@linutronix.de> # hellcreek
Reviewed-by: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>
Reviewed-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Use the newly introduced lynx_pcs_create_mdiodev() which simplifies the
creation and destruction of the lynx PCS.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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In order to not transmit (preemptible) frames which will be received by
the link partner as corrupted (because it doesn't support FP), the
hardware requires the driver to program the QSYS_PREEMPTION_CFG_P_QUEUES
register only after the MAC Merge layer becomes active (verification
succeeds, or was disabled).
There are some cases when FP is known (through experimentation) to be
broken. Give priority to FP over cut-through switching, and disable FP
for known broken link modes.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The mqprio queue configuration can appear either through
TC_SETUP_QDISC_MQPRIO or through TC_SETUP_QDISC_TAPRIO. Make sure both
are treated in the same way.
Code does nothing new for now (except for rejecting multiple TXQs per
TC, which is a useless concept with DSA switches).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ferenc Fejes <fejes@inf.elte.hu>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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This doesn't apply anything to hardware and in general doesn't do
anything that the software variant doesn't do, except for checking that
there isn't more than 1 TXQ per TC (TXQs for a DSA switch are a dubious
concept anyway). The reason we add this is to be able to parse one more
field added to struct tc_mqprio_qopt_offload, namely preemptible_tcs.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ferenc Fejes <fejes@inf.elte.hu>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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When the switch emits an IRQ, we don't know what caused it, and we
iterate through all ports to check the MAC Merge status.
Move that iteration inside the ocelot lib; we will change the locking in
a future change and it would be good to encapsulate that lock completely
within the ocelot lib.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The blamed commit did not properly convert the resource start/end format
into the DEFINE_RES_MEM_NAMED() start/length format, resulting in a
resource for vsc9959_imdio_res which is much longer than expected:
$ cat /proc/iomem
1f8000000-1f815ffff : pcie@1f0000000
1f8140000-1f815ffff : 0000:00:00.5
1f8148030-1f815006f : imdio
vs (correct)
$ cat /proc/iomem
1f8000000-1f815ffff : pcie@1f0000000
1f8140000-1f815ffff : 0000:00:00.5
1f8148030-1f814803f : imdio
Luckily it's not big enough to exceed the size of the parent resource
(pci_resource_end(pdev, VSC9959_IMDIO_PCI_BAR)), and it doesn't overlap
with anything else that the Linux driver uses currently, so the larger
than expected size isn't a practical problem that I can see. Although it
is clearly wrong in the /proc/iomem output.
Fixes: 044d447a801f ("net: dsa: felix: use DEFINE_RES_MEM_NAMED for resources")
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 define FELIX_MAC_QUIRKS was used directly in the felix.c shared driver.
Other devices (VSC7512 for example) don't require the same quirks, so they
need to be configured on a per-device basis.
Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com> # regression
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Felix (VSC9959) has a DEV_GMII:MM_CONFIG block composed of 2 registers
(ENABLE_CONFIG and VERIF_CONFIG). Because the MAC Merge statistics and
pMAC statistics are already in the Ocelot switch lib even if just Felix
supports them, I'm adding support for the whole MAC Merge layer in the
common Ocelot library too.
There is an interrupt (shared with the PTP interrupt) which signals
changes to the MM verification state. This is done because the
preemptible traffic classes should be committed to hardware only once
the verification procedure has declared the link partner of being
capable of receiving preemptible frames.
We implement ethtool getters and setters for the MAC Merge layer state.
The "TX enabled" and "verify status" are taken from the IRQ handler,
using a mutex to ensure serialized access.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The Felix VSC9959 switch supports frame preemption and has a MAC Merge
layer. In addition to the structured stats that exist for the eMAC,
export the counters associated with its pMAC (pause, RMON, MAC, PHY,
control) plus the high-level MAC Merge layer stats. The unstructured
ethtool counters, as well as the rtnl_link_stats64 were left to report
only the eMAC counters.
Because statistics processing is quite self-contained in ocelot_stats.c
now, I've opted for introducing an ocelot->mm_supported bool, based on
which the common switch lib does everything, rather than pushing the
TSN-specific code in felix_vsc9959.c, as happens for other TSN stuff.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The enetc MDIO bus driver can perform both C22 and C45 transfers.
Create separate functions for each and register the C45 versions using
the new API calls where appropriate.
This driver is shared with the Felix DSA switch, so update that at the
same time.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Ever since commit 4d1d157fb6a4 ("net: mscc: ocelot: share the common stat
definitions between all drivers") the stats_layout entry in ocelot and
felix drivers have become redundant. Remove the unnecessary code.
Suggested-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Drop the custom implementation of phylink_validate() in favor of the
generic one, which requires config->mac_capabilities to be set.
This was used up until now because of the possibility of being paired
with Aquantia PHYs with support for rate matching. The phylink framework
gained generic support for these, and knows to advertise all 10/100/1000
lower speed link modes when our SERDES protocol is 2500base-x
(fixed speed).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Our current vsc9959_tas_guard_bands_update() algorithm has a limitation
imposed by the hardware design. To avoid packet overruns between one
gate interval and the next (which would add jitter for scheduled traffic
in the next gate), we configure the switch to use guard bands. These are
as large as the largest packet which is possible to be transmitted.
The problem is that at tc-taprio intervals of sizes comparable to a
guard band, there isn't an obvious place in which to split the interval
between the useful portion (for scheduling) and the guard band portion
(where scheduling is blocked).
For example, a 10 us interval at 1Gbps allows 1225 octets to be
transmitted. We currently split the interval between the bare minimum of
33 ns useful time (required to schedule a single packet) and the rest as
guard band.
But 33 ns of useful scheduling time will only allow a single packet to
be sent, be that packet 1200 octets in size, or 60 octets in size. It is
impossible to send 2 60 octets frames in the 10 us window. Except that
if we reduced the guard band (and therefore the maximum allowable SDU
size) to 5 us, the useful time for scheduling is now also 5 us, so more
packets could be scheduled.
The hardware inflexibility of not scheduling according to individual
packet lengths must unfortunately propagate to the user, who needs to
tune the queueMaxSDU values if he wants to fit more small packets into a
10 us interval, rather than one large packet.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Existing felix DSA drivers (vsc9959, vsc9953) are all switches that were
integrated in NXP SoCs, which makes them a bit unusual compared to the
usual Microchip branded Ocelot switches.
To be precise, looking at
Documentation/devicetree/bindings/net/mscc,vsc7514-switch.yaml, one can
see 21 memory regions for the "switch" node, and these correspond to the
"targets" of the switch IP, which are spread throughout the guts of that
SoC's memory space.
In NXP integrations, those targets still exist, but they were condensed
within a single memory region, with no other peripheral in between them,
so it made more sense for the driver to ioremap the entire memory space
of the switch, and then find the targets within that memory space via
some offsets hardcoded in the driver.
The effect of this design decision is that now, the felix driver expects
hardware instantiations to provide their own resource definitions, which
is kind of odd when considering a typical device (those are retrieved
from 'reg' properties in the device tree, using platform_get_resource()
or similar).
Allow other hardware instantiations that share the felix driver to not
provide a hardcoded array of resources in the future. Instead, make the
common denominator based on which regmaps are created be just the
resource "names". Each instantiation comes with its own array of names
that are mandatory for it, and with an optional array of resources.
So we split the resources in 2 arrays, one is what's requested and the
other is what's provided. There is one pool of provided resources, in
felix->info->resources (of length felix->info->num_resources). There are
2 different ways of requesting a resource. One is by enum ocelot_target
(this handles the global regmaps), and one is by int port (this handles
the per-port ones).
For the existing vsc9959 and vsc9953, it would be a bit stupid to
request something that's not provided, given that the 2 arrays are both
defined in the same place.
The advantage is that we can now modify felix_request_regmap_by_name()
to make felix->info->resources[] optional, and if absent, the
implementation can call dev_get_regmap() and this is something that is
compatible with MFD.
Co-developed-by: Colin Foster <colin.foster@in-advantage.com>
Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Use less verbose resource definitions in vsc9959 and vsc9953. This also
sets IORESOURCE_MEM in the constant array of resources, so we don't have
to do this from felix_init_structs() - in fact, in the future, we may
even support IORESOURCE_REG resources.
Note that this macro takes start and length as argument, and we had
start and end before. So transform end into length.
While at it, sort the resources according to their offset.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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It turns out that the idea of having a customizable implementation of a
regmap creation from a resource is not exactly useful. The idea was for
the new MFD-based VSC7512 driver to use something that creates a SPI
regmap from a resource. But there are problems in actually getting those
resources (it involves getting them from MFD).
To avoid all that, we'll be getting resources by name, so this custom
init_regmap() method won't be needed. Remove it.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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This address is only relevant for the vsc9959, which is a PCIe device
that holds its switch registers in a different PCIe BAR compared to the
registers for the internal MDIO controller.
Hide this aspect from the common felix driver and move the
pci_resource_start() call to the only place that needs it, which is in
vsc9959_mdio_bus_alloc().
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The imdio_res is used only by vsc9959, which references its own
vsc9959_imdio_res through the common felix_info->imdio_res pointer.
Since the common code doesn't care about this resource (and it can't be
part of the common array of resources, either, because it belongs in a
different PCI BAR), just reference it directly.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Remove unnecessary set_drvdata(NULL) function in ->remove(),
the driver_data will be set to NULL in device_unbind_cleanup()
after calling ->remove().
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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All switch families supported by the ocelot lib (ocelot, felix, seville)
export the same registers so far. But for example felix also has TSN
counters, while the others don't.
To reduce the bloat even further, create an OCELOT_COMMON_STATS() macro
which just lists all stats that are common between switches. The array
elements are still replicated among all of vsc9959_stats_layout,
vsc9953_stats_layout and ocelot_stats_layout.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The current definition of struct ocelot_stat_layout is long-winded (4
lines per entry, and we have hundreds of entries), so we could make an
effort to use the C preprocessor and reduce the line count.
Create an implicit correspondence between enum ocelot_reg, which tells
us the register address (SYS_COUNT_RX_OCTETS etc) and enum ocelot_stat
which allows us to index the ocelot->stats array (OCELOT_STAT_RX_OCTETS
etc), and don't require us to specify both when we define what stats
each switch family has.
Create an OCELOT_STAT() macro that pairs only an enum ocelot_stat to an
enum ocelot_reg, and an OCELOT_STAT_ETHTOOL() macro which also contains
a name exported to the unstructured ethtool -S stringset API. For now,
we define all counters as having the OCELOT_STAT_ETHTOOL() kind, but we
will add more counters in the future which are not exported to the
unstructured ethtool -S.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The hardware counter is called C_TX_AGED, so rename SYS_COUNT_TX_AGING
to SYS_COUNT_TX_AGED. This will become important since we want to
minimize the way in which we declare struct ocelot_stat_layout elements,
using the C preprocessor.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The Felix PSFP counters suffer from the same problem as the ocelot
ndo_get_stats64 ones - they are 32-bit, so they can easily overflow and
this can easily go undetected.
Add a custom hook in ocelot_check_stats_work() through which driver
specific actions can be taken, and update the stats for the existing
PSFP filters from that hook.
Previously, vsc9959_psfp_filter_add() and vsc9959_psfp_filter_del() were
serialized with respect to each other via rtnl_lock(). However, with the
new entry point into &psfp->sfi_list coming from the periodic worker, we
now need an explicit mutex to serialize access to these lists.
We used to keep a struct felix_stream_filter_counters on stack, through
which vsc9959_psfp_stats_get() - a FLOW_CLS_STATS callback - would
retrieve data from vsc9959_psfp_counters_get(). We need to become
smarter about that in 3 ways:
- we need to keep a persistent set of counters for each stream instead
of keeping them on stack
- we need to promote those counters from u32 to u64, and create a
procedure that properly keeps 64-bit counters. Since we clear the
hardware counters anyway, and we poll every 2 seconds, a simple
increment of a u64 counter with a u32 value will perfectly do the job.
- FLOW_CLS_STATS also expect incremental counters, so we also need to
zeroize our u64 counters every time sch_flower calls us
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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To support SPI-controlled switches in the future, access to
SYS_STAT_CFG_STAT_VIEW needs to be done outside of any spinlock
protected region, but it still needs to be serialized (by a mutex).
Split the ocelot->stats_lock spinlock into a mutex that serializes
indirect access to hardware registers (ocelot->stat_view_lock) and a
spinlock that serializes access to the u64 ocelot->stats array.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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TSN stream (802.1Qci, 802.1CB) filters are also accessed through
STAT_VIEW, just like the port registers, but these counters are per
stream, rather than per port. So we don't keep them in
ocelot_port_update_stats().
What we can do, however, is we can create register definitions for them
just like we have for the port counters, and delete the last remaining
user of the SYS_CNT register + a group index (read_gix).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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vsc9959_sched_speed_set
The read-modify-write of QSYS_TAG_CONFIG from vsc9959_sched_speed_set()
runs unlocked with respect to the other functions that access it, which
are vsc9959_tas_guard_bands_update(), vsc9959_qos_port_tas_set() and
vsc9959_tas_clock_adjust(). All the others are under ocelot->tas_lock,
so move the vsc9959_sched_speed_set() access under that lock as well, to
resolve the concurrency.
Fixes: 55a515b1f5a9 ("net: dsa: felix: drop oversized frames with tc-taprio instead of hanging the port")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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tc-taprio
Experimentally, it looks like when QSYS_QMAXSDU_CFG_7 is set to 605,
frames even way larger than 601 octets are transmitted even though these
should be considered as oversized, according to the documentation, and
dropped.
Since oversized frame dropping depends on frame size, which is only
known at the EOF stage, and therefore not at SOF when cut-through
forwarding begins, it means that the switch cannot take QSYS_QMAXSDU_CFG_*
into consideration for traffic classes that are cut-through.
Since cut-through forwarding has no UAPI to control it, and the driver
enables it based on the mantra "if we can, then why not", the strategy
is to alter vsc9959_cut_through_fwd() to take into consideration which
tc's have oversize frame dropping enabled, and disable cut-through for
them. Then, from vsc9959_tas_guard_bands_update(), we re-trigger the
cut-through determination process.
There are 2 strategies for vsc9959_cut_through_fwd() to determine
whether a tc has oversized dropping enabled or not. One is to keep a bit
mask of traffic classes per port, and the other is to read back from the
hardware registers (a non-zero value of QSYS_QMAXSDU_CFG_* means the
feature is enabled). We choose reading back from registers, because
struct ocelot_port is shared with drivers (ocelot, seville) that don't
support either cut-through nor tc-taprio, and we don't have a felix
specific extension of struct ocelot_port. Furthermore, reading registers
from the Felix hardware is quite cheap, since they are memory-mapped.
Fixes: 55a515b1f5a9 ("net: dsa: felix: drop oversized frames with tc-taprio instead of hanging the port")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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one packet
The blamed commit broke tc-taprio schedules such as this one:
tc qdisc replace dev $swp1 root taprio \
num_tc 8 \
map 0 1 2 3 4 5 6 7 \
queues 1@0 1@1 1@2 1@3 1@4 1@5 1@6 1@7 \
base-time 0 \
sched-entry S 0x7f 990000 \
sched-entry S 0x80 10000 \
flags 0x2
because the gate entry for TC 7 (S 0x80 10000 ns) now has a static guard
band added earlier than its 'gate close' event, such that packet
overruns won't occur in the worst case of the largest packet possible.
Since guard bands are statically determined based on the per-tc
QSYS_QMAXSDU_CFG_* with a fallback on the port-based QSYS_PORT_MAX_SDU,
we need to discuss what happens with TC 7 depending on kernel version,
since the driver, prior to commit 55a515b1f5a9 ("net: dsa: felix: drop
oversized frames with tc-taprio instead of hanging the port"), did not
touch QSYS_QMAXSDU_CFG_*, and therefore relied on QSYS_PORT_MAX_SDU.
1 (before vsc9959_tas_guard_bands_update): QSYS_PORT_MAX_SDU defaults to
1518, and at gigabit this introduces a static guard band (independent
of packet sizes) of 12144 ns, plus QSYS::HSCH_MISC_CFG.FRM_ADJ (bit
time of 20 octets => 160 ns). But this is larger than the time window
itself, of 10000 ns. So, the queue system never considers a frame with
TC 7 as eligible for transmission, since the gate practically never
opens, and these frames are forever stuck in the TX queues and hang
the port.
2 (after vsc9959_tas_guard_bands_update): Under the sole goal of
enabling oversized frame dropping, we make an effort to set
QSYS_QMAXSDU_CFG_7 to 1230 bytes. But QSYS_QMAXSDU_CFG_7 plays
one more role, which we did not take into account: per-tc static guard
band, expressed in L2 byte time (auto-adjusted for FCS and L1 overhead).
There is a discrepancy between what the driver thinks (that there is
no guard band, and 100% of min_gate_len[tc] is available for egress
scheduling) and what the hardware actually does (crops the equivalent
of QSYS_QMAXSDU_CFG_7 ns out of min_gate_len[tc]). In practice, this
means that the hardware thinks it has exactly 0 ns for scheduling tc 7.
In both cases, even minimum sized Ethernet frames are stuck on egress
rather than being considered for scheduling on TC 7, even if they would
fit given a proper configuration. Considering the current situation,
with vsc9959_tas_guard_bands_update(), frames between 60 octets and 1230
octets in size are not eligible for oversized dropping (because they are
smaller than QSYS_QMAXSDU_CFG_7), but won't be considered as eligible
for scheduling either, because the min_gate_len[7] (10000 ns) minus the
guard band determined by QSYS_QMAXSDU_CFG_7 (1230 octets * 8 ns per
octet == 9840 ns) minus the guard band auto-added for L1 overhead by
QSYS::HSCH_MISC_CFG.FRM_ADJ (20 octets * 8 ns per octet == 160 octets)
leaves 0 ns for scheduling in the queue system proper.
Investigating the hardware behavior, it becomes apparent that the queue
system needs precisely 33 ns of 'gate open' time in order to consider a
frame as eligible for scheduling to a tc. So the solution to this
problem is to amend vsc9959_tas_guard_bands_update(), by giving the
per-tc guard bands less space by exactly 33 ns, just enough for one
frame to be scheduled in that interval. This allows the queue system to
make forward progress for that port-tc, and prevents it from hanging.
Fixes: 297c4de6f780 ("net: dsa: felix: re-enable TAS guard band mode")
Reported-by: Xiaoliang Yang <xiaoliang.yang_1@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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