[PATCH net-next 0/4] Add Ethernet MAC support for SpacemiT K1

[Vivian Wang]

SpacemiT K1 has two gigabit Ethernet MACs with RGMII and RMII support.
Add a driver for them, as well as the supporting devicetree and bindings
updates.

Tested on BananaPi BPI-F3 (but see "Known issues").

I would like to note that even though some bit field names superficially
resemble that of DesignWare MAC, but all other differences point to it
in fact being a custom design.

Based on SpacemiT drivers [1]. This series depends on reset controller
support for K1 [2]. These patches can also be pulled from:

https://github.com/dramforever/linux/tree/k1/ethernet/v1

Known issues:

- RX fails to achieve close-enough-to gigabit performance for unknown
  reasons. The 6.6-based Linux in the vendor distribution "Bianbu" can
  do over 900 Mbps, so this should be a software problem, but I haven't
  figured out why yet. A cursory look at "top" tells me that ksoftirqd
  takes up almost one entire core, which suggests that RX could be
  compute-bound.

  Tested with Banana Pi BPI-F3:

    # On the BPI-F3
    taskset -c 2 iperf3 -s

    # On the other side
    iperf3 --bitrate 0 --time 10 {--reverse,} {--udp,} -c [ip]

  Results (TX/RX from BPI-F3 perspective):

    TCP TX: 941 Mbits/sec
    UDP TX: 948 Mbits/sec
    TCP RX: 617 Mbits/sec
    UDP RX: 647 Mbits/sec

- No DT for Milk-V Jupiter. I do not have this hardware to test yet.
  If I get access to it later I will add its DT changes.

[1]: https://github.com/spacemit-com/linux-k1x
[2]: https://lore.kernel.org/all/20250613011139.1201702-1-elder@xxxxxxxxxxxx

---
Vivian Wang (4):
      dt-bindings: net: Add support for SpacemiT K1
      net: spacemit: Add K1 Ethernet MAC
      riscv: dts: spacemit: Add Ethernet support for K1
      riscv: dts: spacemit: Add Ethernet support for BPI-F3

 .../devicetree/bindings/net/spacemit,k1-emac.yaml  |   81 +
 arch/riscv/boot/dts/spacemit/k1-bananapi-f3.dts    |   46 +
 arch/riscv/boot/dts/spacemit/k1-pinctrl.dtsi       |   48 +
 arch/riscv/boot/dts/spacemit/k1.dtsi               |   22 +
 drivers/net/ethernet/Kconfig                       |    1 +
 drivers/net/ethernet/Makefile                      |    1 +
 drivers/net/ethernet/spacemit/Kconfig              |   29 +
 drivers/net/ethernet/spacemit/Makefile             |    6 +
 drivers/net/ethernet/spacemit/k1_emac.c            | 2059 ++++++++++++++++++++
 drivers/net/ethernet/spacemit/k1_emac.h            |  416 ++++
 10 files changed, 2709 insertions(+)
---
base-commit: d9946fe286439c2aeaa7953b8c316efe5b83d515
change-id: 20250606-net-k1-emac-3e181508ea64
prerequisite-message-id: <20250613011139.1201702-1-elder@xxxxxxxxxxxx>
prerequisite-patch-id: 2c73c63bef3640e63243ddcf3c07b108d45f6816
prerequisite-patch-id: 0faba75db33c96a588e722c4f2b3862c4cbdaeae
prerequisite-patch-id: 5db8688ef86188ec091145fae9e14b2211cd2b8c
prerequisite-patch-id: e0fe84381637dc888d996a79ea717ff0e3441bd1
prerequisite-patch-id: 2fc0ef1c2fcda92ad83400da5aadaf194fe78627
prerequisite-patch-id: bfa54447803e5642059c386e2bd96297e691d0bf

Best regards,
-- 
Vivian "dramforever" Wang