1. 23 Sep, 2021 2 commits
    • Vladimir Oltean's avatar
      net: dsa: move sja1110_process_meta_tstamp inside the tagging protocol driver · 6d709cad
      Vladimir Oltean authored
      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: 566b18c8 ("net: dsa: sja1105: implement TX timestamping for SJA1110")
      Link: https://lore.kernel.org/netdev/20210908220834.d7gmtnwrorhharna@skbuf/Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      6d709cad
    • Vladimir Oltean's avatar
      net: dsa: sja1105: remove sp->dp · 68a81bb2
      Vladimir Oltean authored
      It looks like this field was never used since its introduction in commit
      227d07a0 ("net: dsa: sja1105: Add support for traffic through
      standalone ports") remove it.
      Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      68a81bb2
  2. 22 Sep, 2021 6 commits
  3. 21 Sep, 2021 9 commits
  4. 20 Sep, 2021 15 commits
  5. 19 Sep, 2021 8 commits