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nuttx/arch/arm/src/kinetis/kinetis_start.c

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/****************************************************************************
* arch/arm/src/kinetis/kinetis_start.c
*
* Copyright (C) 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/init.h>
#include "up_arch.h"
#include "up_internal.h"
#include "kinetis.h"
#include "chip/kinetis_smc.h"
#include "kinetis_mpuinit.h"
#include "kinetis_userspace.h"
#ifdef CONFIG_ARCH_FPU
# include "nvic.h"
#endif
#include "kinetis_start.h"
/****************************************************************************
* Private Function prototypes
****************************************************************************/
#ifdef CONFIG_ARCH_FPU
static inline void kinetis_fpuconfig(void);
#endif
#if 0 /* Not used */
#ifdef CONFIG_STACK_COLORATION
static void go_os_start(void *pv, unsigned int nbytes)
__attribute__ ((naked, no_instrument_function, noreturn));
#endif
#endif
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Memory Map ***************************************************************/
/*
* 0x0000:0000 - Beginning of the internal FLASH. Address of vectors.
* Mapped as boot memory address 0x0000:0000 at reset.
* 0x07ff:ffff - End of flash region (assuming the max of 2MiB of FLASH).
* 0x1fff:0000 - Start of internal SRAM and start of .data (_sdata)
* - End of .data (_edata) and start of .bss (_sbss)
* - End of .bss (_ebss) and bottom of idle stack
* - _ebss + CONFIG_IDLETHREAD_STACKSIZE = end of idle stack,
* start of heap. NOTE that the ARM uses a decrement before
* store stack so that the correct initial value is the end of
* the stack + 4;
* 0x2002:ffff - End of internal SRAM and end of heap (a
*/
#define IDLE_STACK ((uintptr_t)&_ebss+CONFIG_IDLETHREAD_STACKSIZE-4)
#define HEAP_BASE ((uintptr_t)&_ebss+CONFIG_IDLETHREAD_STACKSIZE)
/****************************************************************************
* Public Data
****************************************************************************/
/* g_idle_topstack: _sbss is the start of the BSS region as defined by the
* linker script. _ebss lies at the end of the BSS region. The idle task
* stack starts at the end of BSS and is of size CONFIG_IDLETHREAD_STACKSIZE.
* The IDLE thread is the thread that the system boots on and, eventually,
* becomes the IDLE, do nothing task that runs only when there is nothing
* else to run. The heap continues from there until the end of memory.
* g_idle_topstack is a read-only variable the provides this computed
* address.
*/
#if defined(CONFIG_ARMV7M_CMNVECTOR)
const uintptr_t g_idle_topstack = HEAP_BASE;
#endif
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
#ifdef CONFIG_ARMV7M_STACKCHECK
/* we need to get r10 set before we can allow instrumentation calls */
void __start(void) __attribute__ ((no_instrument_function));
#endif
/****************************************************************************
* Name: kinetis_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
#if defined(CONFIG_ARMV7M_CMNVECTOR) && !defined(CONFIG_ARMV7M_LAZYFPU)
static inline void kinetis_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 kinetis_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 kinetis_fpuconfig()
#endif
/****************************************************************************
* Name: go_os_start
*
* Description:
* Set the IDLE stack to the
*
****************************************************************************/
#if 0 /* Not used */
#ifdef CONFIG_STACK_COLORATION
static void go_os_start(void *pv, unsigned int nbytes)
{
/* Set the IDLE stack to the stack coloration value then jump to
* os_start(). We take extreme care here because were currently
* executing on this stack.
*
* We want to avoid sneak stack access generated by the compiler.
*/
__asm__ __volatile__
(
"\tmovs r1, r1, lsr #2\n" /* R1 = nwords = nbytes >> 2 */
"\tbeq 2f\n" /* (should not happen) */
"\tbic r0, r0, #3\n" /* R0 = Aligned stackptr */
"\tmovw r2, #0xbeef\n" /* R2 = STACK_COLOR = 0xdeadbeef */
"\tmovt r2, #0xdead\n"
"1:\n" /* Top of the loop */
"\tsub r1, r1, #1\n" /* R1 nwords-- */
"\tcmp r1, #0\n" /* Check (nwords == 0) */
"\tstr r2, [r0], #4\n" /* Save stack color word, increment stackptr */
"\tbne 1b\n" /* Bottom of the loop */
"2:\n"
"\tmov r14, #0\n" /* LR = return address (none) */
"\tb os_start\n" /* Branch to os_start */
);
}
#endif
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: _start
*
* Description:
* This is the reset entry point.
*
****************************************************************************/
void __start(void)
{
const uint32_t *src;
uint32_t *dest;
#ifdef CONFIG_ARMV7M_STACKCHECK
/* Set the stack limit before we attempt to call any functions */
__asm__ volatile ("sub r10, sp, %0" : : "r" (CONFIG_IDLETHREAD_STACKSIZE - 64) : );
#endif
/* Disable the watchdog timer */
kinetis_wddisable();
/* 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 initialized 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++;
}
/* Copy any necessary code sections from FLASH to RAM. The correct
* destination in SRAM is given by _sramfuncs and _eramfuncs. The
* temporary location is in flash after the data initialization code
* at _framfuncs
*/
#ifdef CONFIG_ARCH_RAMFUNCS
for (src = &_framfuncs, dest = &_sramfuncs; dest < &_eramfuncs; )
{
*dest++ = *src++;
}
#endif
/* Perform clock and Kinetis module initialization (This depends on
* RAM functions having been copied to RAM).
*/
kinetis_clockconfig();
/* Configure the uart and perform early serial initialization so that we
* can get debug output as soon as possible (This depends on clock
* configuration).
*/
kinetis_fpuconfig();
kinetis_lowsetup();
#ifdef USE_EARLYSERIALINIT
kinetis_earlyserialinit();
#endif
/* 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
* segments.
*/
#ifdef CONFIG_BUILD_PROTECTED
kinetis_userspace();
#else
# ifdef KINETIS_MPU
/* Disable the MPU so that all master may access all buses */
kinetis_mpudisable();
# endif
#endif
/* Initialize other on-board resources */
kinetis_boardinitialize();
/* Show reset status */
_warn("Reset status: %02x:%02x\n",
getreg8(KINETIS_SMC_SRSH), getreg8(KINETIS_SMC_SRSL));
/* Then start NuttX */
os_start();
/* Shouldn't get here */
for (; ; );
}
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