[PATCH net-next v2 0/2] net: stmmac: Add support for Allwinner A733 GMAC210

[Jerome Brunet <jbrunet@baylibre.com>]

The A733 GMAC210 is a DesignWare MAC 5.20 with an Allwinner glue close to
the A523 GMAC200 already supported by dwmac-sun55i, but with a few
significant differences:

 * The glue configuration registers are a dedicated MMIO region of the
   controller instead of a syscon register.
 * That region is inside the controller reset domain, so the reset must be
   released before the configuration is written, and must not be asserted
   again afterwards or the configuration is lost.
 * The DMA channels have their own interrupt lines.
 * A PTP reference clock and an AHB reset are needed.
 * The controllers do not require a power domain (AFAIK).
 * The TX clock delay value is 5 bits wide instead of 3, split over 2
   register fields.

The DT changes for the A733 and the Cubie A7A board are not part of this
series and will be sent separately through the sunxi tree.

Tested on a Cubie A7A, RGMII with a MAXIO external PHY on GMAC0.

Problems found while testing (none impacting this driver directly):
 * Unstable EEE/LPI: If the device stays in LPI mode long enough, the                                                                                                                                                   
   link sometimes (but not always) goes down, coming back up when the device
   exits LPI mode. This is apparently due to PHY, the vendor driver disables
   this feature. Solution is to use genphy with eee-broken-* DT prop or wait
   for the incoming mainline driver:
   https://lore.kernel.org/all/MN0PR19MB609154F210DF84DCB29D3696ACC62@MN0PR19MB6091.namprd19.prod.outlook.com
 * Tx-delay: The vendor kernel ships with a Tx delay of 1.2ns. It may seem
   to work at first but breaks under heavy load. It turns out the vendor kernel
   is configured for an external RGMII clock but this can't work on the A7A.
   Th 125MHz input and 25Mhz reference output are not wired to the PHY.
   Most likely, It was not tested on this device. Using 0.9ns Tx-delays works well.

DT example is available here (gated on CCU and pinctrl mainline support currently):
https://github.com/jbrun3t/linux/commit/7b8be41a4130d2471b187b3a1ab33643970ef8a7

Changes in v2:
- No driver change since RFC, just more tests.
- Rebase on net-next/main - proper prefix added
- Link to v1: https://patch.msgid.link/20260731-allwinner-a733-gmac-support-v1-0-d0a8732bfa82@baylibre.com

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
Jerome Brunet (2):
      dt-bindings: net: sun8i-emac: Add A733 GMAC210 compatible
      net: stmmac: Add support for Allwinner A733 GMAC210

 .../bindings/net/allwinner,sun8i-a83t-emac.yaml    | 130 +++++++++++++++---
 drivers/net/ethernet/stmicro/stmmac/dwmac-sun55i.c | 145 ++++++++++++++++++---
 2 files changed, 242 insertions(+), 33 deletions(-)
---
base-commit: 211f2a875f6f447745d80d5762d6d614503ac84a
change-id: 20260731-allwinner-a733-gmac-support-163bde10c152

Best regards,
--  
Jerome