Re: [PATCH v3 net-next 16/24] net: dsa: sja1105: Add support for VLAN operations

[Jiri Pirko]

Sat, Apr 13, 2019 at 03:28:14AM CEST, olteanv@xxxxxxxxx wrote:
>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 (ETH_P_EDSA) 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@xxxxxxxxx>
>Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
>---
>Changes from v3:
>Changed back to ETH_P_EDSA.
>
>Changes from v2:
>Changed the TPID from ETH_P_EDSA (0xDADA) to a newly introduced one:
>ETH_P_DSA_8021Q (0xDADB).
>
> drivers/net/dsa/sja1105/sja1105_main.c        | 254 +++++++++++++++++-
> .../net/dsa/sja1105/sja1105_static_config.c   |  38 +++
> .../net/dsa/sja1105/sja1105_static_config.h   |   3 +
> 3 files changed, 293 insertions(+), 2 deletions(-)
>

[...]


>+#define sja1105_vlan_filtering_enabled(priv) \
>+	(((struct sja1105_general_params_entry *) \
>+	((struct sja1105_private *)priv)->static_config. \
>+	tables[BLK_IDX_GENERAL_PARAMS].entries)->tpid == ETH_P_8021Q)

This is unreadable. Please have it as function.