DHCP error in LwIP Ethernet middleware on STM32H755 CM4

[MasatoKawatsuma]

The problem ethernet link with NUCLEO-H755ZI-Q.
The conditions are as follows:

• Board: NUCLEO-H755ZI-Q
• Ethenet select core: CM4
• STM32Cube_FW_H7: V1.12.1
• LWIP: V2.1.2
• DHCP client

In this case, the Ack from the DHCP server could not be confirmed as being received.
dhcp->pcb_allocated is set to 0 (in function of dhcp_recv()).
A similar error has not occurred with CM7.

Do you happen to know the reason for this?

[mƎALLEm]

Hello @MasatoKawatsuma and welcome to the community,

Related question raised on this thread.

[Billy OWEN]

Hi @MasatoKawatsuma 

This post has been escalated to the ST Online Support Team for additional assistance.  We'll contact you directly.

Regards,

Billy

[MasatoKawatsuma]

The above thread mentions MPU, but I don't use MPU in my environment.
・RTOS disabled
・MPU not used

Also, the following warning occurred while debugging dhcp, so I think it might be a problem with pbuf memory management.

Assertion "pbuf_free: p->ref > 0" failed at line 753 in {path}/Middlewares/Third_Party/LwIP/src/core/pbuf.c

If you know anything, please let me know.

[mƎALLEm · Accepted solution]

---

@MasatoKawatsuma wrote:

The above thread mentions MPU, but I don't use MPU in my environment.
・RTOS disabled
・MPU not used

 No the problem in that thread is not only about the MPU configuration but also linked to the memory partition.

So check also your SRAM memory partitioning.

[MasatoKawatsuma]

Thank you.
I had not assigned LWIP to SRAM3 in the linker file, so setting it as follows solved the problem.

MEMORY
{
FLASH (rx)     : ORIGIN = 0x08100000, LENGTH = 1024K
RAM (xrw)      : ORIGIN = 0x10000000, LENGTH = 256K
RAM_LWIP (xrw) : ORIGIN = 0x10000000 + 256K, LENGTH = 32K
}

...

  .lwip_sec (NOLOAD) :
  {
    . = ABSOLUTE(0x10040000);
    *(.RxDecripSection)

    . = ABSOLUTE(0x10040060);
    *(.TxDecripSection)

    . = ABSOLUTE(0x10040200);
    *(.Rx_PoolSection)
  } >RAM_LWIP