i.MX8M Nano Memory Map

ycx — Wed, 13 Oct 2021 14:09:22 GMT

Hi,

I am currently developing a firmware on the Cortex-M7 of the i.MX8M Nano (MIMX8MN4CVTIZ) based on an example using RPmsg-lite, remoteproc, FreeRTOS and CMSIS-DSP.

I try to build using the linker file MIMX8MN4xxxxx_cm7_ram.ld provided by the MCUXpresso SDK with the following configuration :

/* Specify the memory areas */
MEMORY
{
  m_interrupts          (RX)  : ORIGIN = 0x00000000, LENGTH = 0x00000240
  m_text                (RX)  : ORIGIN = 0x00000240, LENGTH = 0x0001FDC0
  m_data                (RW)  : ORIGIN = 0x20000000, LENGTH = 0x00020000
  m_data2               (RW)  : ORIGIN = 0x80000000, LENGTH = 0x01000000
}

Which would apparently start at the ITCM of the system according to the declared memory map :

When I build the text section is quite big (mostly due to CMSIS-DSP) :

Memory region Used Size Region Size %age Used m_interrupts: 576 B 576 B 100.00% m_text: 123704 B 130496 B 94.80% m_data: 61032 B 128 KB 46.56% m_data2: 0 GB 16 MB 0.00%

And when I run it I get this error :

[ 82.135828] imx-rproc imx8mn-cm7: Translation failed: da = 0x1e578 len = 0xee68
[ 82.143174] remoteproc remoteproc0: bad phdr da 0x1e578 mem 0xee68

In the output.map I see the address in error corresponds to __DATA_ROM, the end of the text section :

0x000000000001e578 __etext = . 0x000000000001e578 __DATA_ROM = . .data 0x0000000020000000 0x98 load address 0x000000000001e578 0x0000000020000000 . = ALIGN (0x4) 0x0000000020000000 __DATA_RAM = . 0x0000000020000000 __data_start__ = . *(.data)

My question is regarding the section declaration of the same linker file (complete file attached) :

   /* The program code and other data goes into internal RAM */
 .text :
 {
   . = ALIGN(4);
   *(.text)                 /* .text sections (code) */
   *(.text*)                /* .text* sections (code) */
   *(.rodata)               /* .rodata sections (constants, strings, etc.) */
   *(.rodata*)              /* .rodata* sections (constants, strings, etc.) */
   *(.glue_7)               /* glue arm to thumb code */
   *(.glue_7t)              /* glue thumb to arm code */
   *(.eh_frame)
   KEEP (*(.init))
   KEEP (*(.fini))
   . = ALIGN(4);
 } > m_text

...

 __etext = .;    /* define a global symbol at end of code */
 __DATA_ROM = .; /* Symbol is used by startup for data initialization */

 .data : AT(__DATA_ROM)
 {
   . = ALIGN(4);
   __DATA_RAM = .;
   __data_start__ = .;      /* create a global symbol at data start */
   *(.data)                 /* .data sections */
   *(.data*)                /* .data* sections */
   KEEP(*(.jcr*))
   . = ALIGN(4);
   __data_end__ = .;        /* define a global symbol at data end */
 } > m_data

Does ".data : AT(__DATA_ROM)" mean that the .data section starts at the end of the .text section ? Why is that and therefore what is the point declaring the start address of m_data in MEMORY {} ?

If I understand correctly this would mean that .data section could overflow the ITCM range, especially when .text is close to its maximum size like my fw. What am I or the linker doing wrong ?

Thanks a lot your help!

Re: i.MX8M Nano Memory Map

Yuri — Thu, 14 Oct 2021 10:36:56 GMT

@ycx
Hello,

Generally the linker file lines below are intended for code / data relocation.

__DATA_ROM = .; /* Symbol is used by startup for data initialization */

.data : AT(__DATA_ROM)
{

Please use the linked below file with explanation how to do it.

https://community.nxp.com/t5/Kinetis-Design-Studio-Knowledge/Relocating-Code-and-Data-Using-the-KDS-GCC-Linker-File-for/ta-p/1121931

In Your case - perhaps - it would be better to try using DRAM configuration; *_cm7_ddr_ram.ld

Regards,
Yuri.

i.MX Processorsのトピックi.MX8M Nano Memory Map

i.MX8M Nano Memory Map

Re: i.MX8M Nano Memory Map