openblt/Target/Source/ARMCM3_STM32/GCC/cstart.c

151 lines
6.2 KiB
C

/****************************************************************************************
| Description: bootloader C startup source file
| File Name: cstart.c
|
|----------------------------------------------------------------------------------------
| C O P Y R I G H T
|----------------------------------------------------------------------------------------
| Copyright (c) 2011 by Feaser http://www.feaser.com All rights reserved
|
|----------------------------------------------------------------------------------------
| L I C E N S E
|----------------------------------------------------------------------------------------
| This file is part of OpenBLT. OpenBLT is free software: you can redistribute it and/or
| modify it under the terms of the GNU General Public License as published by the Free
| Software Foundation, either version 3 of the License, or (at your option) any later
| version.
|
| OpenBLT is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
| without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
| PURPOSE. See the GNU General Public License for more details.
|
| You should have received a copy of the GNU General Public License along with OpenBLT.
| If not, see <http://www.gnu.org/licenses/>.
|
| A special exception to the GPL is included to allow you to distribute a combined work
| that includes OpenBLT without being obliged to provide the source code for any
| proprietary components. The exception text is included at the bottom of the license
| file <license.html>.
|
****************************************************************************************/
/****************************************************************************************
* Include files
****************************************************************************************/
#include "boot.h" /* bootloader generic header */
/****************************************************************************************
* External function protoypes
****************************************************************************************/
extern int main(void);
extern void ComSetConnectEntryState(void);
/****************************************************************************************
* External data declarations
****************************************************************************************/
/* these externals are declared by the linker */
extern blt_int32u _etext;
extern blt_int32u _data;
extern blt_int32u _edata;
extern blt_int32u _bss;
extern blt_int32u _ebss;
extern blt_int32u _estack;
/****************************************************************************************
** NAME: EntryFromProg
** PARAMETER: none
** RETURN VALUE: none
** DESCRIPTION: Called by the user program to activate the bootloader. Do not place
** any assembly code before this function and the end of the vector
** table. This guarantees that this function is located at address
** 0x08000150. The user program can call this function from C in the
** following way:
** void ActivateBootloader(void)
** {
** void (*pEntryFromProgFnc)(void);
**
** pEntryFromProgFnc = (void*)0x08000150;
** pEntryFromProgFnc();
** }
**
****************************************************************************************/
__attribute__ ((section (".entry")))
void EntryFromProg(void)
{
blt_int32u *pSrc, *pDest;
/* disable interrupts first */
__asm(" cpsid i");
/* configure vector table offset register to use bootloader's vector table*/
__asm(" ldr r0, =0xE000ED08\n"
" ldr r1, =_vectab\n"
" str r1, [r0]");
/* initialize stack pointer */
__asm(" ldr r1, =_estack\n"
" mov sp, r1");
/* copy the data segment initializers from flash to SRAM */
pSrc = &_etext;
for(pDest = &_data; pDest < &_edata; )
{
*pDest++ = *pSrc++;
}
/* zero fill the bss segment. this is done with inline assembly since this will
* clear the value of pDest if it is not kept in a register.
*/
__asm(" ldr r0, =_bss\n"
" ldr r1, =_ebss\n"
" mov r2, #0\n"
" .thumb_func\n"
"zero_loop2:\n"
" cmp r0, r1\n"
" it lt\n"
" strlt r2, [r0], #4\n"
" blt zero_loop2");
/* this part makes the difference with the normal reset_handler */
ComSetConnectEntryState();
/* start the software application by calling its entry point */
main();
} /*** end of EntryFromProg ***/
/****************************************************************************************
** NAME: reset_handler
** PARAMETER: none
** RETURN VALUE: none
** DESCRIPTION: Reset interrupt service routine. Configures the stack, initializes
** RAM and jumps to function main.
**
****************************************************************************************/
void reset_handler(void)
{
blt_int32u *pSrc, *pDest;
/* disable interrupts first */
__asm(" cpsid i");
/* copy the data segment initializers from flash to SRAM */
pSrc = &_etext;
for(pDest = &_data; pDest < &_edata; )
{
*pDest++ = *pSrc++;
}
/* zero fill the bss segment. this is done with inline assembly since this will
* clear the value of pDest if it is not kept in a register.
*/
__asm(" ldr r0, =_bss\n"
" ldr r1, =_ebss\n"
" mov r2, #0\n"
" .thumb_func\n"
"zero_loop:\n"
" cmp r0, r1\n"
" it lt\n"
" strlt r2, [r0], #4\n"
" blt zero_loop");
/* start the software application by calling its entry point */
main();
} /*** end of reset_handler ***/
/************************************ end of cstart.c **********************************/