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/****************************************************************************
* arch/arm/src/sam34/sam_start.c
*
* Copyright (C) 2009-2010, 2012-2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/init.h>
#include <arch/board/board.h>
#include "up_arch.h"
#include "up_internal.h"
#include "sam_clockconfig.h"
#include "sam_lowputc.h"
#include "sam_userspace.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#if defined(CONFIG_WDT_ENABLED_ON_RESET) && defined(CONFIG_WDT_DISABLE_ON_RESET)
# define NEED_WDT_DISABLE
#endif
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: showprogress
*
* Description:
* Print a character on the UART to show boot status.
*
****************************************************************************/
#ifdef CONFIG_DEBUG
# define showprogress(c) up_lowputc(c)
#else
# define showprogress(c)
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: _start
*
* Description:
* This is the reset entry point.
*
****************************************************************************/
void __start(void)
{
const uint32_t *src;
uint32_t *dest;
/* Clear .bss. We'll do this inline (vs. calling memset) just to be
* certain that there are no issues with the state of global variables.
*/
for (dest = &_sbss; dest < &_ebss; )
{
*dest++ = 0;
}
/* Move the intialized data section from his temporary holding spot in
* FLASH into the correct place in SRAM. The correct place in SRAM is
* give by _sdata and _edata. The temporary location is in FLASH at the
* end of all of the other read-only data (.text, .rodata) at _eronly.
*/
for (src = &_eronly, dest = &_sdata; dest < &_edata; )
{
*dest++ = *src++;
}
#ifdef NEED_WDT_DISABLE
/* Disable the watchdog timer */
# warning Missing logic
#endif
/* Copy any necessary code sections from FLASH to RAM. The correct
* destination in SRAM is geive by _sramfuncs and _eramfuncs. The
* temporary location is in flash after the data initalization code
* at _framfuncs. This must be done before sam_clockconfig() can be
* called (at least for the SAM4L family).
*/
#ifdef CONFIG_ARCH_RAMFUNCS
for (src = &_framfuncs, dest = &_sramfuncs; dest < &_eramfuncs; )
{
*dest++ = *src++;
}
#endif
/* Configure the uart so that we can get debug output as soon as possible */
sam_clockconfig();
sam_lowsetup();
showprogress('A');
/* Perform early serial initialization */
#ifdef USE_EARLYSERIALINIT
up_earlyserialinit();
#endif
showprogress('B');
/* For the case of the separate user-/kernel-space build, perform whatever
* platform specific initialization of the user memory is required.
* Normally this just means initializing the user space .data and .bss
* segements.
*/
#ifdef CONFIG_NUTTX_KERNEL
sam_userspace();
showprogress('C');
#endif
/* Initialize onboard resources */
sam_boardinitialize();
showprogress('D');
/* Then start NuttX */
showprogress('\r');
showprogress('\n');
os_start();
/* Shouldn't get here */
for(;;);
}
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