The PFCC register is used to configure both PAUSE and PFC frames.
Therefore, when PFC frames are disabled we must make sure we don't
mistakenly also disable PAUSE frames (which might be enabled).
Fix this by packing the PFCC register with the current PAUSE settings.
Note that this register is also accessed via ethtool ops, but there we
are guaranteed to have PFC disabled.
Fixes: d81a6bdb87 ("mlxsw: spectrum: Add IEEE 802.1Qbb PFC support")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When ieee_setpfc() gets called, PAUSE frames are not necessarily
disabled on the port.
Check if PAUSE frames are disabled or enabled and configure the port's
headroom buffer accordingly.
Fixes: d81a6bdb87 ("mlxsw: spectrum: Add IEEE 802.1Qbb PFC support")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Packets entering the switch are mapped to a Switch Priority (SP)
according to their PCP value (untagged frames are mapped to SP 0).
The packets are classified to a priority group (PG) buffer in the port's
headroom according to their SP.
The switch maintains another mapping (SP to IEEE priority), which is
used to generate PFC frames for lossless PGs. This mapping is
initialized to IEEE = SP % 8.
Therefore, when mapping SP 'x' to PG 'y' we create a situation in which
an IEEE priority is mapped to two different PGs:
IEEE 'x' ---> SP 'x' ---> PG 'y'
IEEE 'x' ---> SP 'x + 8' ---> PG '0' (default)
Which is invalid, as a flow can use only one PG buffer.
Fix this by mapping both SP 'x' and 'x + 8' to the same PG buffer.
Fixes: 8e8dfe9fdf ("mlxsw: spectrum: Add IEEE 802.1Qaz ETS support")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The number of supported traffic classes that can have ETS and PFC
simultaneously enabled is not subject to user configuration, so make
sure we always initialize them to the correct values following a set
operation.
Fixes: 8e8dfe9fdf ("mlxsw: spectrum: Add IEEE 802.1Qaz ETS support")
Fixes: d81a6bdb87 ("mlxsw: spectrum: Add IEEE 802.1Qbb PFC support")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We can't have PAUSE frames and PFC both enabled on the same port, but
the fact that ieee_setpfc() was called doesn't necessarily mean PFC is
enabled.
Only emit errors when PAUSE frames and PFC are enabled simultaneously.
Fixes: d81a6bdb87 ("mlxsw: spectrum: Add IEEE 802.1Qbb PFC support")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Implement the appropriate DCB ops and allow a user to configure certain
traffic classes as lossless.
The operation configures PFC for both the egress (respecting PFC frames)
and ingress (sending PFC frames) parts of the port.
At egress, when a PFC frame is received for a PFC enabled priority, then
all the priorities mapped to the same TC are stopped.
At ingress, the priority group (PG) buffers to which the enabled PFC
priorities are mapped are configured to be lossless. PFC frames will be
transmitted when the Xoff threshold is crossed.
The user-supplied delay parameter is used to determine the PG's size
according to the following formula:
PG_SIZE = PG_SIZE_LOSSY + delay * CELL_FACTOR + MTU
In the worst case scenario the delay will be made up of packets that
are all of size CELL_SIZE + 1, which means each packet will require
almost twice its true size when buffered in the switch. We therefore
multiply this value by the "cell factor", which is close to 2.
Another MTU is added in case the transmitting host already started
transmitting a maximum length frame when the PFC packet was received.
As with PAUSE enabled ports, when the port's MTU is changed both the
PGs' size and threshold are adjusted accordingly.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When a packet ingress the switch it's placed in its assigned priority
group (PG) buffer in the port's headroom buffer while it goes through
the switch's pipeline. After going through the pipeline - which
determines its egress port(s) and traffic class - it's moved to the
switch's shared buffer awaiting transmission.
However, some packets are not eligible to enter the shared buffer due to
exceeded quotas or insufficient space. Marking their associated PGs as
lossless will cause the packets to accumulate in the PG buffer. Another
reason for packets accumulation are complicated pipelines (e.g.
involving a lot of ACLs).
To prevent packets from being dropped a user can enable PAUSE frames on
the port. This will mark all the active PGs as lossless and set their
size according to the maximum delay, as it's not configured by user.
+----------------+ +
| | |
| | |
| | |
| | |
| | |
| | | Delay
| | |
| | |
| | |
| | |
| | |
Xon/Xoff threshold +----------------+ +
| | |
| | | 2 * MTU
| | |
+----------------+ +
The delay (612 [Cells]) was calculated according to worst-case scenario
involving maximum MTU and 100m cables.
After marking the PGs as lossless the device is configured to respect
incoming PAUSE frames (Rx PAUSE) and generate PAUSE frames (Tx PAUSE)
according to user's settings.
Whenever the port's headroom configuration changes we take into account
the PAUSE configuration, so that we correctly set the PG's type (lossy /
lossless), size and threshold. This can happen when:
a) The port's MTU changes, as it directly affects the PG's size.
b) A PG is created following user configuration, by binding a priority
to it.
Note that the relevant SUPPORTED flags were already mistakenly set by
the driver before this commit.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Allow a user to set maximum rate for a particular TC using DCB ops.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Implement the appropriate DCB ops and allow a user to configure:
* Priority to traffic class (TC) mapping with a total of 8
supported TCs
* Transmission selection algorithm (TSA) for each TC and the
corresponding weights in case of weighted round robin (WRR)
As previously explained, we treat the priority group (PG) buffer in the
port's headroom as the ingress counterpart of the egress TC. Therefore,
when a certain priority to TC mapping is configured, we also configure
the port's headroom buffer.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Introduce basic infrastructure for DCB and add the missing ops in
following patches.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
