H723ZG Ethernet MPU: Should Rx_PoolSection still be included in the _FLASH.ld?

[eduardo_reis]

I have a NUCLEO-H723ZG.

From the STM32 examples, in the LwIP_UDP_Echo_Server/STM32CubeIDE/STM32H723ZGTX_FLASH.ld file, we have:

.lwip_sec (NOLOAD) : {
    . = ABSOLUTE(0x30000000);
    *(.RxDecripSection) 
    
    . = ABSOLUTE(0x30000200);
    *(.TxDecripSection)
    
    . = ABSOLUTE(0x30000400);
    *(.Rx_PoolSection) 
  } >RAM_D2 AT> ROM

 However, when creating a project with STM32CubeIDE 1.13.1, We don't get to set the Rx_PoolSection. Also, in the generated ethernetif.c file I got:

#if defined ( __ICCARM__ ) /*!< IAR Compiler */

#pragma location=0x30000000
ETH_DMADescTypeDef  DMARxDscrTab[ETH_RX_DESC_CNT]; /* Ethernet Rx DMA Descriptors */
#pragma location=0x30000100
ETH_DMADescTypeDef  DMATxDscrTab[ETH_TX_DESC_CNT]; /* Ethernet Tx DMA Descriptors */

#elif defined ( __CC_ARM )  /* MDK ARM Compiler */

__attribute__((at(0x30000000))) ETH_DMADescTypeDef  DMARxDscrTab[ETH_RX_DESC_CNT]; /* Ethernet Rx DMA Descriptors */
__attribute__((at(0x30000100))) ETH_DMADescTypeDef  DMATxDscrTab[ETH_TX_DESC_CNT]; /* Ethernet Tx DMA Descriptors */

#elif defined ( __GNUC__ ) /* GNU Compiler */

ETH_DMADescTypeDef DMARxDscrTab[ETH_RX_DESC_CNT] __attribute__((section(".RxDecripSection"))); /* Ethernet Rx DMA Descriptors */
ETH_DMADescTypeDef DMATxDscrTab[ETH_TX_DESC_CNT] __attribute__((section(".TxDecripSection")));   /* Ethernet Tx DMA Descriptors */

#endif

Should Rx_PoolSection be just ignored, hence not included in the _FLASH.ld file?

[KDJEM.1]

Hello @eduardo_reis ,

It is mentioned in this FAQ: How to create project for STM32H7 with Ethernet an... - STMicroelectronics Community : After generate project with STM32CubeIDE, you need to modify the code by placement of the RX_POOL buffers in ethernetif.c* (example with STM32H750).

/* USER CODE BEGIN 2 */
#if defined ( __ICCARM__ ) /*!< IAR Compiler */
#pragma location = 0x30040200
extern u8_t memp_memory_RX_POOL_base[];

#elif defined ( __CC_ARM )  /* MDK ARM Compiler */
__attribute__((at(0x30040200)) extern u8_t memp_memory_RX_POOL_base[];

#elif defined ( __GNUC__ ) /* GNU Compiler */
__attribute__((section(".Rx_PoolSection"))) extern u8_t memp_memory_RX_POOL_base[];

#endif
/* USER CODE END 2 */

Then, modify the linkerscript. This step should be skipped for Keil and IAR, since they support placing variables at specific address in C code. Modify the linkerscript (*.ld) that the ETH descriptors and buffers are located in D2 SRAM. 

Note (*) these addresses and sizes depend on the device or core used.

For more information I advise you to take a look at How do I create a project for STM32H7 with Ethernet and LwIP stack working?

Thank you.

Kaouthar

[eduardo_reis]

Hello @KDJEM.1, thank you for your response.

Would it be possible to be a bit more clear?

As I said, I am using the H723ZG, which Memory layout points its address as AXI SRAM (32-byte aligned).

Variable STM32H72x/H73x address Size Source file

DMARxDscrTab	0x30000000	96 (256 max.)	ethernetif.c
DMATxDscrTab	0x30000100	96 (256 max.)	ethernetif.c
memp_memory_RX_POOL_base	AXI SRAM (32-byte aligned)	12*(1536 + 24)	ethernetif.c
LwIP heap	0x30000200	32232 (32kB - 512 - 24)	lwipopts.h

-----

---

@KDJEM.1 wrote:you need to modify the code by placement of the RX_POOL buffers in ethernetif.c* (example with STM32H750).

---

What do you mean by modify since there is no description for memp_memory_RX_POOL_base in the ethernetif.c file, as I pasted it above?

Should I include it?

[KDJEM.1 · Accepted solution]

Hello @eduardo_reis ,

To clarify my last reply: 

-->H723ZG Ethernet MPU: Should Rx_PoolSection still be included in the _FLASH.ld?

Yes.

When you creating a new project with STM32CubeIDE, you need to add manually RX_POOL buffers in ethernetif.c and  to modify linkerscript. 

I hope this answer your request 🙂.

Thank you.

Kaouthar