[PATCH net-next 0/2] net: stmmac: dwmac4: Auto-discover UC filter size

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

Following my attempts to get clean ethtool selftests runs on stmmac [1],
several issues were found with the unicast filtering.

[1]: https://lore.kernel.org/netdev/20260827134004.45ffb57e@kernel.org/

This lead to the discovery that on dwmac4 platforms, the unicast filter
size is always falling back to the default value of 1 entry. On older
variants, the size comes from devicetree.

With a single-entry filter, we directly fallback to unicast promisc as
soon as any entry is added in the dev->uc list.

dwmac4 exposes through the HW_Features0 register the actual size of the
unicast filter, which is made of 3 banks (details in patch 2). Let's use
this feature to grab the filter size.

Results on actual hardware :

 - imx8mp   : goes from 1 entry to 64
 - stm32mp1 : goes from 1 entry to 4
 - jh7110   : goes from 1 entry to 9
 - yt6801   : still 1 single entry, on extra implemented in HW

Maxime Chevallier (2):
  net: stmmac: dwmac4: Read the UC filter size from hardware
    capabilities
  net: stmmac: dwmac4: Use the full perfect filter ability for UC filter

 drivers/net/ethernet/stmicro/stmmac/common.h  |  5 ++
 drivers/net/ethernet/stmicro/stmmac/dwmac4.h  |  6 +-
 .../net/ethernet/stmicro/stmmac/dwmac4_core.c | 60 +++++++++++++++----
 .../net/ethernet/stmicro/stmmac/dwmac4_dma.c  |  2 +
 .../net/ethernet/stmicro/stmmac/stmmac_main.c | 39 ++++++++++++
 5 files changed, 99 insertions(+), 13 deletions(-)

-- 
2.55.0