boards/arm/stm32h7/nucleo-h723zg: Add support for 10BASE-T1S SPI Ethernet, remove untested/unsupported code, improve stability

[matiamic]

Summary

This patch removes unsupported/untested code from the nucleo-h723zg's BSP, improves stability by increasing its stack sizes and introduces support for 10BASE-T1S SPI MAC-PHYs.

Impact

The patch consists of four commits:

1. Remove unsupported/untested code from the BSP's bringup.
   I noticed that in the
   PR boards/arm/stm32h7: Add support for the NUCLEO-H723ZG board #18475 in stm32_bringup.c
   I left remains of code linked to unsupported functionalities and bits of code that I didn't test.
   These remains and bits are removed by this commit.

2. Improve stability of the nsh and netnsh defconfigs by increasing stack sizes.

3. Add support for the subsystem for 10BASE-T1S SPI Ethernet MAC-PHYs based on the OA-TC6 protocol.

4. Add documentation for the oa_tc6 defconfig

Testing

1. The correct build was tested, additionally I2C was tested with an INA219 module and i2ctool.
2. A call to ps and connecting to a telnet session caused overflowing of the stack. After the change, no more crashes were encountered.
3. The support for the 10BASE-T1S SPI Ethernet was tested with ping on a small 10BASE-T1S network.

[michallenc]

LGTM

[linguini1]

Looks good to me as well, are you able to provide the log output for this part of your testing?

A call to ps and connecting to a telnet session caused overflowing of the stack. After the change, no more crashes were encountered.

[matiamic]

The following is a scenario in which ps is called from the telnet session.

Calling ps from the telnet client

michal@michal-ThinkPad-X250:~$ telnet 10.0.0.2
Trying 10.0.0.2...
Connected to 10.0.0.2.
Escape character is '^]'.

NuttShell (NSH) NuttX-12.12.0
nsh> ps
nsh: &ps: command not found
nsh> ps
  PID  PPID GROUP PRI POLICY   TYPE    NPX STATE    EVENT     SIGMASK            STACK COMMAND

Serial console crash dump

telnetd [4:100]

NuttShell (NSH) NuttX-12.12.0
nsh> dump_assert_info: Current Version: NuttX  12.12.0 f8307643a0 Mar  7 2026 22:52:03 arm
dump_assert_info: Assertion failed panic: at file: :0 task: <noname> process: <noname> 0x800fff1
up_dump_register: R0: 00000000 R1: 300039e4 R2: 30003578  R3: 00000000
up_dump_register: R4: 30003c5c R5: 08048678 R6: 00000000  FP: 00000000
up_dump_register: R8: 00000000 SB: 00000000 SL: 00000000 R11: 00000000
up_dump_register: IP: 00000000 SP: 30003a10 LR: 0800ca6b  PC: 0803605c
up_dump_register: xPSR: 21000000 BASEPRI: 00000000 CONTROL: 00000000
up_dump_register: EXC_RETURN: ffffffed
dump_stackinfo: User Stack:
dump_stackinfo:   base: 0x30003578
dump_stackinfo:   size: 00002000
dump_stackinfo:     sp: 0x30003a10
stack_dump: 0x300039f0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 08036059
stack_dump: 0x30003a10: 30004060 00000000 30003a68 08028433 53205850 0800d9a1 30003a68 00000c01
stack_dump: 0x30003a30: 080499fc 300034ac 30007ff8 00000001 00000030 30004090 30003280 08028559
stack_dump: 0x30003a50: 00000000 080499fc 30003a68 00000028 08035dab 00000c01 00000001 30004060
stack_dump: 0x30003a70: 080181d3 080499fc 08049934 30004060 080499b0 08016b53 080499a4 0804999c
stack_dump: 0x30003a90: 08018289 080499fc 080498fc 30003d60 08049978 08049970 00003ba0 00000000
stack_dump: 0x30003ab0: 30003c5c 08018401 30003af3 08040225 24008d70 30003ba0 00000001 30003d60
stack_dump: 0x30003ad0: ffffffff 08003717 fffffffe 300031d8 00000000 00003c5c 08048678 08013985
stack_dump: 0x30003af0: 0000401b 08048c37 30003c4c 08014135 30004018 30003ba0 00000001 30003d60
stack_dump: 0x30003b10: 30003b38 30004018 0801836d 080491f4 30003c5c 08010d63 3000401a 00000000
stack_dump: 0x30003b30: 30003c4c 30003ba0 00000001 30003d60 08048659 30004018 00000000 30003be8
stack_dump: 0x30003b50: 30003b9c 30003d60 30003be8 00000000 30003b98 ffffffff 00000000 00000001
stack_dump: 0x30003b70: 00000000 30003c5c 08048678 080122c7 30003b94 30002f80 30004018 30003d60
stack_dump: 0x30003b90: 00000001 00000000 30004018 3000401b 30004018 00000000 00000000 00000000
stack_dump: 0x30003bb0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
stack_dump: 0x30003bd0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
stack_dump: 0x30003bf0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
stack_dump: 0x30003c10: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
stack_dump: 0x30003c30: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 ffffffff
stack_dump: 0x30003c50: ffffffff 00000000 00000000 00000000 00000000 0000000a 0000000a 08048400
stack_dump: 0x30003c70: 30003cb8 00003c78 080483fc 00000001 00000040 00000001 240001c0 08012389
stack_dump: 0x30003c90: 30004018 30003d60 08048378 00000005 00000300 080299ef 08010085 3000401a
stack_dump: 0x30003cb0: 00000002 30003fb0 30004018 30004018 00000001 0800ffbf 00000000 000002f8
stack_dump: 0x30003cd0: 30003560 00000001 00000002 30003d60 30003d60 00000003 00000000 00000000
stack_dump: 0x30003cf0: 00000000 0801000d 30003560 00000001 00000000 30003d60 00000000 0800aab5
stack_dump: 0x30003d10: 00000000 30003560 00000001 0800fff1 00000000 08005ab9 00000000 30003560
stack_dump: 0x30003d30: 00000000 300031d8 00000001 00000001 00000000 00000000 00000000 00000000
dump_tasks:    PID GROUP PRI POLICY   TYPE    NPX STATE   EVENT      SIGMASK          STACKBASE  STACKSIZE   COMMAND
dump_tasks:   ----   --- --- -------- ------- --- ------- ---------- ---------------- 0x24000840      2048   irq
dump_task:       0     0   0 FIFO     Kthread -   Ready              0000000000000000 0x2400a150      1000   <noname>
dump_task:       1     0 224 RR       Kthread -   Waiting Semaphore  0000000000000000 0x30000328      1976   <noname> 0x240000b8 0x24000100
dump_task:       2     0 100 RR       Kthread -   Waiting Semaphore  0000000000000000 0x30000bd8      1976   <noname> 0x2400011c 0x24000164
dump_task:       3     3 100 RR       Task    -   Waiting Semaphore  0000000000000000 0x30001758      2000   <noname>
dump_task:       4     4 100 RR       Task    -   Waiting Semaphore  0000000000000000 0x300026f8      2008   <noname>