/****************************************************************************
* arch/arm/src/stm32/stm32_start.c
* arch/arm/src/chip/stm32_start.c
*
* Copyright (C) 2009, 2011-2012 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.
*
****************************************************************************/
#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 "stm32_internal.h"
#include "stm32_gpio.h"
#ifdef CONFIG_ARCH_FPU
# include "nvic.h"
#endif
/****************************************************************************
* 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: stm32_fpuconfig
*
* Description:
* Configure the FPU. Relative bit settings:
*
* CPACR: Enables access to CP10 and CP11
* CONTROL.FPCA: Determines whether the FP extension is active in the
* current context:
* FPCCR.ASPEN: Enables automatic FP state preservation, then the
* processor sets this bit to 1 on successful completion of any FP
* instruction.
* FPCCR.LSPEN: Enables lazy context save of FP state. When this is
* done, the processor reserves space on the stack for the FP state,
* but does not save that state information to the stack.
*
* Software must not change the value of the ASPEN bit or LSPEN bit while either:
* - the CPACR permits access to CP10 and CP11, that give access to the FP
* extension, or
* - the CONTROL.FPCA bit is set to 1
*
****************************************************************************/
#ifdef CONFIG_ARCH_FPU
#ifdef CONFIG_ARMV7M_CMNVECTOR
static inline void stm32_fpuconfig(void)
{
uint32_t regval;
/* Set CONTROL.FPCA so that we always get the extended context frame
* with the volatile FP registers stacked above the basic context.
*/
regval = getcontrol();
regval |= (1 << 2);
setcontrol(regval);
/* Ensure that FPCCR.LSPEN is disabled, so that we don't have to contend
* with the lazy FP context save behaviour. Clear FPCCR.ASPEN since we
* are going to turn on CONTROL.FPCA for all contexts.
*/
regval = getreg32(NVIC_FPCCR);
regval &= ~((1 << 31) | (1 << 30));
putreg32(regval, NVIC_FPCCR);
/* Enable full access to CP10 and CP11 */
regval = getreg32(NVIC_CPACR);
regval |= ((3 << (2*10)) | (3 << (2*11)));
putreg32(regval, NVIC_CPACR);
}
#else
static inline void stm32_fpuconfig(void)
{
uint32_t regval;
/* Clear CONTROL.FPCA so that we do not get the extended context frame
* with the volatile FP registers stacked in the saved context.
*/
regval = getcontrol();
regval &= ~(1 << 2);
setcontrol(regval);
/* Ensure that FPCCR.LSPEN is disabled, so that we don't have to contend
* with the lazy FP context save behaviour. Clear FPCCR.ASPEN since we
* are going to keep CONTROL.FPCA off for all contexts.
*/
regval = getreg32(NVIC_FPCCR);
regval &= ~((1 << 31) | (1 << 30));
putreg32(regval, NVIC_FPCCR);
/* Enable full access to CP10 and CP11 */
regval = getreg32(NVIC_CPACR);
regval |= ((3 << (2*10)) | (3 << (2*11)));
putreg32(regval, NVIC_CPACR);
}
#endif
#else
# define stm32_fpuconfig()
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: _start
*
* Description:
* This is the reset entry point.
*
****************************************************************************/
void __start(void)
{
const uint32_t *src;
uint32_t *dest;
/* Configure the uart so that we can get debug output as soon as possible */
stm32_clockconfig();
stm32_fpuconfig();
stm32_lowsetup();
stm32_gpioinit();
showprogress('A');
/* 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;
}
showprogress('B');
/* 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++;
}
showprogress('C');
/* Perform early serial initialization */
#ifdef USE_EARLYSERIALINIT
up_earlyserialinit();
#endif
showprogress('D');
/* Initialize onboard resources */
stm32_boardinitialize();
showprogress('E');
/* Then start NuttX */
showprogress('\r');
showprogress('\n');
os_start();
/* Shoulnd't get here */
for(;;);
}
