cmemoryembeddedramtruestudio

Give the priority of the IRAM to a specific source file in C

I'm looking for a way to give the priority of the IRAM to a specific source file and let others source files by default.

From Keil uVision I was able to do it by going in the file options :

enter image description here

I migrated my project to Atollic TrueSTUDIO (generated with CubeMx) and there's no options like these. I found information about how to set where starts the RAM and its size in the linker script STM32F765NG_FLASH.id.

/* Specify the memory areas */
MEMORY
{
RAM (xrw)      : ORIGIN = 0x20000000, LENGTH = 512K
FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 1024K
}

I imagine that there's maybe a way to modify this file to specify which .c file need the priority on the IRAM, but I don't know where and how to do it.

I also found __ attribute__ that I can use in the variable declaration. When I use it, it compiles, but it breaks some functionalities of the code (it probably override other data).

uint8_t __attribute__((section(".ARM.__at_0x20000000"))) RxSerialDMABuffer[RX_DMA_BUFFER_SIZE] = {0};
uint8_t __attribute__((section(".ARM.__at_0x20001000"))) TxDMABuffer[TX_DMA_BUFFER_SIZE] = {0};

So my question is, how can I set a particular source file to have the priority to use the IRAM before all my others files without the Keil uVision options?

EDIT : This is the complete linker script

/*
*****************************************************************************
**

**  File        : stm32_flash.ld
**
**  Abstract    : Linker script for STM32F765NG Device with
**                1024KByte FLASH, 512KByte RAM
**
**                Set heap size, stack size and stack location according
**                to application requirements.
**
**                Set memory bank area and size if external memory is used.
**
**  Target      : STMicroelectronics STM32
**
**  Environment : Atollic TrueSTUDIO(R)
**
**  Distribution: The file is distributed as is, without any warranty
**                of any kind.
**
**  (c)Copyright Atollic AB.
**  You may use this file as-is or modify it according to the needs of your
**  project. This file may only be built (assembled or compiled and linked)
**  using the Atollic TrueSTUDIO(R) product. The use of this file together
**  with other tools than Atollic TrueSTUDIO(R) is not permitted.
**
*****************************************************************************
*/

/* Entry Point */
ENTRY(Reset_Handler)

/* Highest address of the user mode stack */
_estack = 0x20080000;    /* end of RAM */
/* Generate a link error if heap and stack don't fit into RAM */
_Min_Heap_Size = 0x00002200;      /* required amount of heap  */
_Min_Stack_Size = 0x00001200; /* required amount of stack */

/* Specify the memory areas */
MEMORY
{
RAM (xrw)      : ORIGIN = 0x20000000, LENGTH = 512K
FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 1024K
}

/* Define output sections */
SECTIONS
{
  /* The startup code goes first into FLASH */
  .isr_vector :
  {
    . = ALIGN(4);
    KEEP(*(.isr_vector)) /* Startup code */
    . = ALIGN(4);
  } >FLASH

  /* The program code and other data goes into FLASH */
  .text :
  {
    . = ALIGN(4);
    *(.text)           /* .text sections (code) */
    *(.text*)          /* .text* sections (code) */
    *(.glue_7)         /* glue arm to thumb code */
    *(.glue_7t)        /* glue thumb to arm code */
    *(.eh_frame)

    KEEP (*(.init))
    KEEP (*(.fini))

    . = ALIGN(4);
    _etext = .;        /* define a global symbols at end of code */
  } >FLASH

  /* Constant data goes into FLASH */
  .rodata :
  {
    . = ALIGN(4);
    *(.rodata)         /* .rodata sections (constants, strings, etc.) */
    *(.rodata*)        /* .rodata* sections (constants, strings, etc.) */
    . = ALIGN(4);
  } >FLASH

  .ARM.extab   : { *(.ARM.extab* .gnu.linkonce.armextab.*) } >FLASH
  .ARM : {
    __exidx_start = .;
    *(.ARM.exidx*)
    __exidx_end = .;
  } >FLASH

  .preinit_array     :
  {
    PROVIDE_HIDDEN (__preinit_array_start = .);
    KEEP (*(.preinit_array*))
    PROVIDE_HIDDEN (__preinit_array_end = .);
  } >FLASH
  .init_array :
  {
    PROVIDE_HIDDEN (__init_array_start = .);
    KEEP (*(SORT(.init_array.*)))
    KEEP (*(.init_array*))
    PROVIDE_HIDDEN (__init_array_end = .);
  } >FLASH
  .fini_array :
  {
    PROVIDE_HIDDEN (__fini_array_start = .);
    KEEP (*(SORT(.fini_array.*)))
    KEEP (*(.fini_array*))
    PROVIDE_HIDDEN (__fini_array_end = .);
  } >FLASH

  /* used by the startup to initialize data */
  _sidata = LOADADDR(.data);

  /* Initialized data sections goes into RAM, load LMA copy after code */
  .data : 
  {
    . = ALIGN(4);
    _sdata = .;        /* create a global symbol at data start */
    *(.data)           /* .data sections */
    *(.data*)          /* .data* sections */

    . = ALIGN(4);
    _edata = .;        /* define a global symbol at data end */
  } >RAM AT> FLASH


  /* Uninitialized data section */
  . = ALIGN(4);
  .bss :
  {
    /* This is used by the startup in order to initialize the .bss secion */
    _sbss = .;         /* define a global symbol at bss start */
    __bss_start__ = _sbss;
    *(.bss)
    *(.bss*)
    *(COMMON)

    . = ALIGN(4);
    _ebss = .;         /* define a global symbol at bss end */
    __bss_end__ = _ebss;
  } >RAM

  /* User_heap_stack section, used to check that there is enough RAM left */
  ._user_heap_stack :
  {
    . = ALIGN(4);
    PROVIDE ( end = . );
    PROVIDE ( _end = . );
    . = . + _Min_Heap_Size;
    . = . + _Min_Stack_Size;
    . = ALIGN(4);
  } >RAM



  /* Remove information from the standard libraries */
  /DISCARD/ :
  {
    libc.a ( * )
    libm.a ( * )
    libgcc.a ( * )
  }

  .ARM.attributes 0 : { *(.ARM.attributes) }
}
Solution

  • To give the priority of the RAM to my buffers, I loaded them in RAM first.

    By going with the file name, the linker was reporting an error for multiple definitions. So I added a section attribute to my buffers like I did in my question, but by giving a section name instead of an address.

    uint8_t RxSerialDMABuffer[RX_DMA_BUFFER_SIZE] __attribute__ ((section ("BUFFERS"))) = {0};
uint8_t TxDMABuffer[TX_DMA_BUFFER_SIZE] __attribute__ ((section ("BUFFERS"))) = {0};

    After this, I added the new section in RAM before the other uninitialized data.

      /* Uninitialized buffers section */
  .BUFFERS :
  {
    * (.BUFFERS)
  } >RAM

  /* Uninitialized data section */
  . = ALIGN(4);
  .bss :
  {
    /* This is used by the startup in order to initialize the .bss secion */
    _sbss = .;         /* define a global symbol at bss start */
    __bss_start__ = _sbss;
    *(.bss)
    *(.bss*)
    *(COMMON)

    . = ALIGN(4);
    _ebss = .;         /* define a global symbol at bss end */
    __bss_end__ = _ebss;
  } >RAM

    Then I went in the Linker Address Map file and I saw all my buffers with addresses corresponding to my IRAM2 address range, and all the other uninitialized data with the next addresses in IRAM2, then IRAM1.