/**************************************************************************** * arch/arm/src/stm32/stm32_start.c * * Copyright (C) 2009, 2011-2018 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #include "up_arch.h" #include "up_internal.h" #include "stm32.h" #include "stm32_gpio.h" #include "stm32_userspace.h" #ifdef CONFIG_ARCH_FPU # include "nvic.h" #endif #include "stm32_start.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /* .data is positioned first in the primary RAM followed immediately by .bss. * The IDLE thread stack lies just after .bss and has size give by * CONFIG_IDLETHREAD_STACKSIZE; The heap then begins just after the IDLE. * ARM EABI requires 64 bit stack alignment. */ #define IDLE_STACKSIZE (CONFIG_IDLETHREAD_STACKSIZE & ~7) #define IDLE_STACK ((uintptr_t)&_ebss + IDLE_STACKSIZE) #define HEAP_BASE ((uintptr_t)&_ebss + IDLE_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. */ const uintptr_t g_idle_topstack = HEAP_BASE; /**************************************************************************** * Private Function prototypes ****************************************************************************/ #ifdef CONFIG_ARCH_FPU static inline void stm32_fpuconfig(void); #endif #ifdef CONFIG_STACK_COLORATION static void go_nx_start(void *pv, unsigned int nbytes) __attribute__ ((naked, no_instrument_function, noreturn)); #endif /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: showprogress * * Description: * Print a character on the UART to show boot status. * ****************************************************************************/ #ifdef CONFIG_DEBUG_FEATURES # define showprogress(c) up_lowputc(c) #else # define showprogress(c) #endif /**************************************************************************** * Public 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: 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 #ifndef CONFIG_ARMV7M_LAZYFPU 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 /**************************************************************************** * Name: go_nx_start * * Description: * Set the IDLE stack to the coloration value and jump into nx_start() * ****************************************************************************/ #ifdef CONFIG_STACK_COLORATION static void go_nx_start(void *pv, unsigned int nbytes) { /* Set the IDLE stack to the stack coloration value then jump to * nx_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 */ "\tcmp r1, #0\n" /* Check (nwords == 0) */ "\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 nx_start\n" /* Branch to nx_start */ ); } #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 /* 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 = _START_BSS; dest < _END_BSS; ) { *dest++ = 0; } showprogress('B'); /* 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 = _DATA_INIT, dest = _START_DATA; dest < _END_DATA; ) { *dest++ = *src++; } showprogress('C'); #ifdef CONFIG_ARMV7M_ITMSYSLOG /* Perform ARMv7-M ITM SYSLOG initialization */ itm_syslog_initialize(); #endif /* Perform early serial initialization */ #ifdef USE_EARLYSERIALINIT up_earlyserialinit(); #endif showprogress('D'); /* 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 stm32_userspace(); showprogress('E'); #endif /* Initialize onboard resources */ stm32_boardinitialize(); showprogress('F'); /* Then start NuttX */ showprogress('\r'); showprogress('\n'); #ifdef CONFIG_STACK_COLORATION /* Set the IDLE stack to the coloration value and jump into nx_start() */ go_nx_start((FAR void *)&_ebss, CONFIG_IDLETHREAD_STACKSIZE); #else /* Call nx_start() */ nx_start(); /* Shoulnd't get here */ for (; ; ); #endif }