Hi All,

On 14.09.2025 06:23, Vivian Wang wrote:

SpacemiT K1 has two gigabit Ethernet MACs with RGMII and RMII support.
Add devicetree bindings, driver, and DTS for it.

Tested primarily on BananaPi BPI-F3. Basic TX/RX functionality also
tested on Milk-V Jupiter.

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

Based on SpacemiT drivers [1]. These patches are also available at:

https://github.com/dramforever/linux/tree/k1/ethernet/v12

[1]: https://github.com/spacemit-com/linux-k1x

This driver recently landed in linux-next as commit bfec6d7f2001 ("net: 
spacemit: Add K1 Ethernet MAC"). In my tests I found that it 
triggers lock dep warnings related to stats_lock acquisition. In the 
current code it is being acquired with spin_lock(). For tests I've 
changed that to spin_lock_irqsave() and the warnings went away, but I'm 
not sure that this is the proper fix. I've also checked the driver 
history and 'irqsave' locking was used in pre-v7 version, but it was 
removed later on Jakub's request and described a bit misleading as 
"Removed scoped_guard usage".

Here are the lock dep warnings I got on my BananaPiF3 board:

================================
WARNING: inconsistent lock state
6.17.0-rc6-next-20250918 #11165 Not tainted
--------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
swapper/0/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
ffffffd60b1412a0 (&priv->stats_lock){+.?.}-{3:3}, at: 
emac_stats_timer+0x1c/0x3e [k1_emac]
{SOFTIRQ-ON-W} state was registered at:
   __lock_acquire+0x7f6/0x1f7c
   lock_acquire+0xe8/0x2b6
   _raw_spin_lock+0x2c/0x40
   emac_get_stats64+0xbc/0x188 [k1_emac]
   dev_get_stats+0x3e/0x292
   rtnl_fill_stats+0x32/0xec
   rtnl_fill_ifinfo.constprop.0+0x6d0/0x1448
   rtmsg_ifinfo_build_skb+0x92/0xea
   rtmsg_ifinfo+0x36/0x78
   register_netdevice+0x7a6/0x7d4
   register_netdev+0x20/0x36
   devm_register_netdev+0x58/0xb0
   emac_probe+0x3bc/0x5ce [k1_emac]
   platform_probe+0x46/0x84
   really_probe+0x108/0x2e0
   __driver_probe_device.part.0+0xaa/0xe0
   driver_probe_device+0x78/0xc4
   __driver_attach+0x54/0x162
   bus_for_each_dev+0x58/0xa4
   driver_attach+0x1a/0x22
   bus_add_driver+0xec/0x1ce
   driver_register+0x3e/0xd8
   __platform_driver_register+0x1c/0x24
   0xffffffff025bb020
   do_one_initcall+0x56/0x290
   do_init_module+0x52/0x1da
   load_module+0x1590/0x19d8
   init_module_from_file+0x76/0xae
   idempotent_init_module+0x186/0x1fc
   __riscv_sys_finit_module+0x54/0x84
   do_trap_ecall_u+0x2a0/0x4d0
   handle_exception+0x146/0x152
irq event stamp: 76398
hardirqs last  enabled at (76398): [<ffffffff80b8809c>] 
_raw_spin_unlock_irq+0x2a/0x42
hardirqs last disabled at (76397): [<ffffffff80b87e52>] 
_raw_spin_lock_irq+0x5a/0x60
softirqs last  enabled at (76376): [<ffffffff8002e8ca>] 
handle_softirqs+0x3ca/0x462
softirqs last disabled at (76389): [<ffffffff8002eaca>] 
__irq_exit_rcu+0xe2/0x10c

other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&priv->stats_lock);
   <Interrupt>
     lock(&priv->stats_lock);

  *** DEADLOCK ***

1 lock held by swapper/0/0:
  #0: ffffffc600003c30 ((&priv->stats_timer)){+.-.}-{0:0}, at: 
call_timer_fn+0x0/0x24e

stack backtrace:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 
6.17.0-rc6-next-20250918 #11165 NONE
Hardware name: Banana Pi BPI-F3 (DT)
Call Trace:
[<ffffffff800163a6>] dump_backtrace+0x1c/0x24
[<ffffffff80001482>] show_stack+0x28/0x34
[<ffffffff8000f7ca>] dump_stack_lvl+0x5e/0x86
[<ffffffff8000f806>] dump_stack+0x14/0x1c
[<ffffffff80090a80>] print_usage_bug.part.0+0x29a/0x302
[<ffffffff80091152>] mark_lock+0x66a/0x7ee
[<ffffffff80091cfe>] __lock_acquire+0x7cc/0x1f7c
[<ffffffff80093d0c>] lock_acquire+0xe8/0x2b6
[<ffffffff80b87d18>] _raw_spin_lock+0x2c/0x40
[<ffffffff025c61da>] emac_stats_timer+0x1c/0x3e [k1_emac]
[<ffffffff800d8de4>] call_timer_fn+0x90/0x24e
[<ffffffff800d91b0>] __run_timers+0x20e/0x2e8
[<ffffffff800d98ea>] timer_expire_remote+0x4a/0x5e
[<ffffffff800efe52>] tmigr_handle_remote_up+0x174/0x34a
[<ffffffff800ee5e0>] __walk_groups.isra.0+0x28/0x66
[<ffffffff800f0128>] tmigr_handle_remote+0x9e/0xc2
[<ffffffff800d931c>] run_timer_softirq+0x2a/0x32
[<ffffffff8002e662>] handle_softirqs+0x162/0x462
[<ffffffff8002eaca>] __irq_exit_rcu+0xe2/0x10c
[<ffffffff8002efac>] irq_exit_rcu+0xc/0x36
[<ffffffff80b7b248>] handle_riscv_irq+0x64/0x74
[<ffffffff80b898aa>] call_on_irq_stack+0x32/0x40



================================
WARNING: inconsistent lock state
6.17.0-rc6-next-20250918-dirty #11166 Not tainted
--------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
swapper/4/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
ffffffd606ca92a0 (&priv->stats_lock){+.?.}-{3:3}, at: 
emac_stats_timer+0x1c/0x3e [k1_emac]
{SOFTIRQ-ON-W} state was registered at:
   __lock_acquire+0x7f6/0x1f7c
   lock_acquire+0xe8/0x2b6
   _raw_spin_lock+0x2c/0x40
   emac_open+0x820/0x9b0 [k1_emac]
   __dev_open+0xca/0x21c
   __dev_change_flags+0x18a/0x204
   netif_change_flags+0x1e/0x56
   do_setlink.constprop.0+0x268/0xb88
   rtnl_newlink+0x57a/0x788
   rtnetlink_rcv_msg+0x3ea/0x54c
   netlink_rcv_skb+0x44/0xec
   rtnetlink_rcv+0x14/0x1c
   netlink_unicast+0x1b6/0x218
   netlink_sendmsg+0x174/0x34e
   __sock_sendmsg+0x40/0x7c
   ____sys_sendmsg+0x19c/0x1ba
   ___sys_sendmsg+0x5c/0xa0
   __sys_sendmsg+0x5a/0xa2
   __riscv_sys_sendmsg+0x16/0x1e
   do_trap_ecall_u+0x2a0/0x4d0
   handle_exception+0x146/0x152
irq event stamp: 36278
hardirqs last  enabled at (36278): [<ffffffff80b8809c>] 
_raw_spin_unlock_irq+0x2a/0x42
hardirqs last disabled at (36277): [<ffffffff80b87e52>] 
_raw_spin_lock_irq+0x5a/0x60
softirqs last  enabled at (36256): [<ffffffff8002e8ca>] 
handle_softirqs+0x3ca/0x462
softirqs last disabled at (36269): [<ffffffff8002eaca>] 
__irq_exit_rcu+0xe2/0x10c

other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&priv->stats_lock);
   <Interrupt>
     lock(&priv->stats_lock);

  *** DEADLOCK ***

1 lock held by swapper/4/0:
  #0: ffffffc600023c30 ((&priv->stats_timer)){+.-.}-{0:0}, at: 
call_timer_fn+0x0/0x24e

stack backtrace:
CPU: 4 UID: 0 PID: 0 Comm: swapper/4 Not tainted 
6.17.0-rc6-next-20250918-dirty #11166 NONE
Hardware name: Banana Pi BPI-F3 (DT)
Call Trace:
[<ffffffff800163a6>] dump_backtrace+0x1c/0x24
[<ffffffff80001482>] show_stack+0x28/0x34
[<ffffffff8000f7ca>] dump_stack_lvl+0x5e/0x86
[<ffffffff8000f806>] dump_stack+0x14/0x1c
[<ffffffff80090a80>] print_usage_bug.part.0+0x29a/0x302
[<ffffffff80091152>] mark_lock+0x66a/0x7ee
[<ffffffff80091cfe>] __lock_acquire+0x7cc/0x1f7c
[<ffffffff80093d0c>] lock_acquire+0xe8/0x2b6
[<ffffffff80b87d18>] _raw_spin_lock+0x2c/0x40
[<ffffffff025b41da>] emac_stats_timer+0x1c/0x3e [k1_emac]
[<ffffffff800d8de4>] call_timer_fn+0x90/0x24e
[<ffffffff800d91b0>] __run_timers+0x20e/0x2e8
[<ffffffff800d98ea>] timer_expire_remote+0x4a/0x5e
[<ffffffff800efe52>] tmigr_handle_remote_up+0x174/0x34a
[<ffffffff800ee5e0>] __walk_groups.isra.0+0x28/0x66
[<ffffffff800f0128>] tmigr_handle_remote+0x9e/0xc2
[<ffffffff800d931c>] run_timer_softirq+0x2a/0x32
[<ffffffff8002e662>] handle_softirqs+0x162/0x462
[<ffffffff8002eaca>] __irq_exit_rcu+0xe2/0x10c
[<ffffffff8002efac>] irq_exit_rcu+0xc/0x36
[<ffffffff80b7b248>] handle_riscv_irq+0x64/0x74
[<ffffffff80b898aa>] call_on_irq_stack+0x32/0x40

---
Changes in v12:
- Add aliases ethernet{0,1} to DTS
- Minor changes
   - Use FIELD_MODIFY to set duplex mode in HW based on phydev->duplex
   - Use FIELD_GET in emac_mii_read() to extract bits from MAC_MDIO_DATA
- Link to v11: https://lore.kernel.org/r/20250912-net-k1-emac-v11-0-aa3e84f8043b@iscas.ac.cn (local)

Changes in v11:
- Use NETDEV_PCPU_STAT_DSTATS for tx_dropped
- Use DECLARE_FLEX_ARRAY for emac_hw_{tx,rx}_stats instead of cast
- More bitfields stuff to simplify code:
   - Define EMAC_MAX_DELAY_UNIT with FIELD_MAX
   - Use FIELD_{PREP,GET} in emac_mii_{read,write}()
   - Use FIELD_MODIFY in emac_set_{tx,rx}_fc()
- Minor changes:
   - Use lower_32_bits and such instead of casts and shifts
   - Extract emac_ether_addr_hash() helper
   - In emac_mdio_init(), 0xffffffff -> ~0
   - Minor comment changes
- Link to v10: https://lore.kernel.org/r/20250908-net-k1-emac-v10-0-90d807ccd469@iscas.ac.cn (local)

Changes in v10:
- Use FIELD_GET and FIELD_PREP, remove some unused constants
- Remove redundant software statistics
   - In particular, rx_dropped should have been and is already tracked in
     rx_errors.
- Track tx_dropped with a percpu field
- Minor changes
   - Simplified int emac_rx_frame_status() -> bool emac_rx_frame_good()
- Link to v9: https://lore.kernel.org/r/20250905-net-k1-emac-v9-0-f1649b98a19c@iscas.ac.cn (local)

Changes in v9:
- Refactor to use phy_interface_mode_is_rgmii
- Minor changes
   - Use netdev_err in more places
   - Print phy-mode by name on unsupported phy-mode
- Link to v8: https://lore.kernel.org/r/20250828-net-k1-emac-v8-0-e9075dd2ca90@iscas.ac.cn (local)

Changes in v8:
- Use devres to do of_phy_deregister_fixed_link on probe failure or
   remove
- Simplified control flow in a few places with early return or continue
- Minor changes
   - Removed some unneeded parens in emac_configure_{tx,rx}
- Link to v7: https://lore.kernel.org/r/20250826-net-k1-emac-v7-0-5bc158d086ae@iscas.ac.cn (local)

Changes in v7:
- Removed scoped_guard usage
- Renamed error handling path labels after destinations
- Fix skb free error handling path in emac_start_xmit and emac_tx_mem_map
- Cancel tx_timeout_task to prevent schedule_work lifetime problems
- Minor changes:
   - Remove unnecessary timer_delete_sync in emac_down
   - Use dev_err_ratelimited in a few more places
   - Cosmetic fixes in error messages
- Link to v6: https://lore.kernel.org/r/20250820-net-k1-emac-v6-0-c1e28f2b8be5@iscas.ac.cn (local)

Changes in v6:
- Implement pause frame support
- Minor changes:
   - Convert comment for emac_stats_update() into assert_spin_locked()
   - Cosmetic fixes for some comments and whitespace
   - emac_set_mac_addr() is now refactored
- Link to v5: https://lore.kernel.org/r/20250812-net-k1-emac-v5-0-dd17c4905f49@iscas.ac.cn (local)

Changes in v5:
- Rebased on v6.17-rc1, add back DTS now that they apply cleanly
- Use standard statistics interface, handle 32-bit statistics overflow
- Minor changes:
   - Fix clock resource handling in emac_resume
   - Ratelimit the message in emac_rx_frame_status
   - Add ndo_validate_addr = eth_validate_addr
   - Remove unnecessary parens in emac_set_mac_addr
   - Change some functions that never fail to return void instead of int
   - Minor rewording
- Link to v4: https://lore.kernel.org/r/20250703-net-k1-emac-v4-0-686d09c4cfa8@iscas.ac.cn (local)

Changes in v4:
- Resource handling on probe and remove: timer_delete_sync and
   of_phy_deregister_fixed_link
- Drop DTS changes and dependencies (will send through SpacemiT tree)
- Minor changes:
   - Remove redundant phy_stop() and setting of ndev->phydev
   - Fix error checking for emac_open in emac_resume
   - Fix one missed dev_err -> dev_err_probe
   - Fix type of emac_start_xmit
   - Fix one missed reverse xmas tree formatting
   - Rename some functions for consistency between emac_* and ndo_*
- Link to v3: https://lore.kernel.org/r/20250702-net-k1-emac-v3-0-882dc55404f3@iscas.ac.cn (local)

Changes in v3:
- Refactored and simplified emac_tx_mem_map
- Addressed other minor v2 review comments
- Removed what was patch 3 in v2, depend on DMA buses instead
- DT nodes in alphabetical order where appropriate
- Link to v2: https://lore.kernel.org/r/20250618-net-k1-emac-v2-0-94f5f07227a8@iscas.ac.cn (local)

Changes in v2:
- dts: Put eth0 and eth1 nodes under a bus with dma-ranges
- dts: Added Milk-V Jupiter
- Fix typo in emac_init_hw() that broke the driver (Oops!)
- Reformatted line lengths to under 80
- Addressed other v1 review comments
- Link to v1: https://lore.kernel.org/r/20250613-net-k1-emac-v1-0-cc6f9e510667@iscas.ac.cn (local)

---
Vivian Wang (5):
       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
       riscv: dts: spacemit: Add Ethernet support for Jupiter

  .../devicetree/bindings/net/spacemit,k1-emac.yaml  |   81 +
  arch/riscv/boot/dts/spacemit/k1-bananapi-f3.dts    |   48 +
  arch/riscv/boot/dts/spacemit/k1-milkv-jupiter.dts  |   48 +
  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            | 2159 ++++++++++++++++++++
  drivers/net/ethernet/spacemit/k1_emac.h            |  416 ++++
  11 files changed, 2859 insertions(+)
---
base-commit: 062b3e4a1f880f104a8d4b90b767788786aa7b78
change-id: 20250606-net-k1-emac-3e181508ea64

Best regards,

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland