Use CCM for stack and data sections

* Update linker script to use CCM for stack and data.
* Reserve main RAM block for heap.
* Update std library with weak _sbrk symbol.
* Override _sbrk to use entire main RAM block for malloc.
This commit is contained in:
iabdalkader 2014-01-24 13:37:30 +02:00
parent 5f152403fb
commit 387f04d80d
4 changed files with 50 additions and 87 deletions

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@ -265,19 +265,6 @@ void usb_data_out(void *buffer, int *length, void *user_data)
}
}
/* This function loads the .ccm data into the CMM region
It's here to avoid modifiying the startup code */
void load_ccm_section () __attribute__ ((section (".init")));
void load_ccm_section (){
extern char _eidata, _sccm, _eccm;
char *src = &_eidata;
char *dst = &_sccm;
while (dst < &_eccm) {
*dst++ = *src++;
}
}
int main(void)
{
/* sensor handle */

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@ -1,53 +1,26 @@
/*
*****************************************************************************
**
** File : stm32_flash.ld
**
** Abstract : Linker script for STM32F407VG Device with
** 1024KByte FLASH, 192KByte 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. Distribution of this file (unmodified or modified) is not
** permitted. Atollic AB permit registered Atollic TrueSTUDIO(R) users the
** rights to distribute the assembled, compiled & linked contents of this
** file as part of an application binary file, provided that it is built
** using the Atollic TrueSTUDIO(R) toolchain.
**
*****************************************************************************
*/
/**
* Linker script for STM32F4xx Devices with 1MB FLASH, 192KB RAM (64KB CCM)
*/
/* Entry Point */
ENTRY(Reset_Handler)
/* Highest address of the user mode stack */
_estack = 0x20020000; /* end of 128K RAM on AHB bus*/
/* Generate a link error if heap and stack don't fit into RAM */
_Min_Heap_Size = 0; /* required amount of heap */
_Min_Stack_Size = 0x400; /* required amount of stack */
_Min_Stack_Size = 0x1000; /* required amount of stack */
/* Specify the memory areas */
MEMORY
{
FLASH (rx) : ORIGIN = 0x08000000, LENGTH = 512K
RAM (xrw) : ORIGIN = 0x20000000, LENGTH = 128K
MEMORY_B1 (rx) : ORIGIN = 0x60000000, LENGTH = 0K
CCM (w!rx) : ORIGIN = 0x10000000, LENGTH = 64K
}
/* Highest address of the user mode stack */
_estack = 0x10010000; /* Stack is allocated on CCM block */
_heap_start = 0x20000000; /* Heap starts at the main RAM block */
_heap_end = 0x20020000; /* Heap is given the whole RAM block */
/* Define output sections */
SECTIONS
{
@ -79,20 +52,20 @@ SECTIONS
_exit = .;
} >FLASH
.ARM.extab : { *(.ARM.extab* .gnu.linkonce.armextab.*) } >FLASH
.ARM : {
__exidx_start = .;
*(.ARM.exidx*)
__exidx_end = .;
} >FLASH
.ARM.extab : { *(.ARM.extab* .gnu.linkonce.armextab.*) } >FLASH
.ARM : {
__exidx_start = .;
*(.ARM.exidx*)
__exidx_end = .;
} >FLASH
.preinit_array :
.preinit_array :
{
PROVIDE_HIDDEN (__preinit_array_start = .);
KEEP (*(.preinit_array*))
PROVIDE_HIDDEN (__preinit_array_end = .);
} >FLASH
.init_array :
{
PROVIDE_HIDDEN (__init_array_start = .);
@ -100,6 +73,7 @@ SECTIONS
KEEP (*(.init_array*))
PROVIDE_HIDDEN (__init_array_end = .);
} >FLASH
.fini_array :
{
PROVIDE_HIDDEN (__fini_array_start = .);
@ -122,20 +96,7 @@ SECTIONS
. = ALIGN(4);
_edata = .; /* define a global symbol at data end */
} >RAM
/* This section will load the .ccm data into FLASH,
a C function in .init section copies the .ccm data
from FLASH to CCM memory in runtime. */
_eidata = (_sidata + SIZEOF(.data) + SIZEOF(.jcr));
.ccm : AT ( _sidata + SIZEOF(.data) + SIZEOF(.jcr))
{
. = ALIGN(4);
_sccm = .;
*(.ccm)
. = ALIGN(4);
_eccm = .;
}>CCM
} >CCM
/* Uninitialized data section */
. = ALIGN(4);
@ -151,28 +112,15 @@ SECTIONS
. = ALIGN(4);
_ebss = .; /* define a global symbol at bss end */
__bss_end__ = _ebss;
} >RAM
} >CCM
/* User_heap_stack section, used to check that there is enough RAM left */
/* Make sure there is enough RAM left for the stack */
._user_heap_stack :
{
. = ALIGN(4);
PROVIDE ( end = . );
PROVIDE ( _end = . );
. = . + _Min_Heap_Size;
. = . + _Min_Stack_Size;
. = ALIGN(4);
} >RAM
/* MEMORY_bank1 section, code must be located here explicitly */
/* Example: extern int foo(void) __attribute__ ((section (".mb1text"))); */
.memory_b1_text :
{
*(.mb1text) /* .mb1text sections (code) */
*(.mb1text*) /* .mb1text* sections (code) */
*(.mb1rodata) /* read-only data (constants) */
*(.mb1rodata*)
} >MEMORY_B1
} >CCM
/* Remove information from the standard libraries */
/DISCARD/ :

28
src/syscalls.c Normal file
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@ -0,0 +1,28 @@
#include <errno.h>
#include <stdint.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/times.h>
/**
* Override _sbrk.
* uses the whole main RAM block (128KB) for heap.
*/
caddr_t _sbrk(int incr) {
extern char _heap_start; // Defined by the linker
extern char _heap_end; // Defined by the linker
static char *heap_end;
char *prev_heap_end;
if (heap_end == 0) {
heap_end = &_heap_start;
}
prev_heap_end = heap_end;
if (heap_end + incr > &_heap_end) {
errno = ENOMEM;
return (caddr_t) - 1;
}
heap_end += incr;
return (caddr_t) prev_heap_end;
}