flight/pios/stm32f30x/startup.c

   1 /**
   2  ******************************************************************************
   3  * @addtogroup PIOS PIOS Core hardware abstraction layer
   4  * @{
   5  *
   6  * @file       startup.c
   7  * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2012.
   8  * @author     Tau Labs, http://taulabs.org, Copyright (C) 2012-2013
   9  * @brief      C based startup of F3
  10  * @see        The GNU Public License (GPL) Version 3
  11  *
  12  *****************************************************************************/
  13 /*
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 3 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful, but
  20  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  21  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  22  * for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License along
  25  * with this program; if not, write to the Free Software Foundation, Inc.,
  26  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  27  */
  28
  29
  30 #include <string.h>
  31 #include <stm32f30x.h>
  32
  33 /* prototype for main() that tells us not to worry about it possibly returning */
  34 extern int              main(void) __attribute__((noreturn));
  35
  36 /* prototype our _main() to avoid prolog/epilog insertion and other related junk */
  37 void                    _main(void) __attribute__((noreturn, naked, no_instrument_function));
  38
  39 /** default handler for CPU exceptions */
  40 static void             default_cpu_handler(void) __attribute__((noreturn, naked, no_instrument_function));
  41
  42 /** BSS symbols XXX should have a header that defines all of these */
  43 extern char _sbss, _ebss;
  44
  45 /** DATA symbols XXX should have a header that defines all of these */
  46 extern char _sidata, _sdata, _edata, _sfast, _efast;
  47
  48 /** The bootstrap/IRQ stack XXX should define size somewhere else */
  49 char irq_stack[1024] __attribute__((section(".irqstack")));
  50
  51 /** exception handler */
  52 typedef void (vector)(void);
  53
  54 /** CortexM3 CPU vectors */
  55 struct cm3_vectors {
  56     void   *initial_stack;
  57     vector *entry;
  58     vector *vectors[14];
  59 };
  60
  61 /**
  62  * Initial startup code.
  63  */
  64 void _main(void)
  65 {
  66     // load the stack base for the current stack before we attempt to branch to any function
  67     // that might bounds-check the stack
  68     asm volatile ("mov r10, %0" : : "r" (&irq_stack[0]) :);
  69
  70     /* enable usage, bus and memory faults */
  71     SCB->SHCSR  |= SCB_SHCSR_USGFAULTENA_Msk | SCB_SHCSR_BUSFAULTENA_Msk | SCB_SHCSR_MEMFAULTENA_Msk;
  72
  73     /* configure FP state save behaviour - automatic, lazy save */
  74     FPU->FPCCR  |= FPU_FPCCR_ASPEN_Msk | FPU_FPCCR_LSPEN_Msk;
  75
  76     /* configure default FPU state */
  77     FPU->FPDSCR |= FPU_FPDSCR_DN_Msk; /* enable Default NaN */
  78     FPU->FPDSCR |= FPU_FPDSCR_FZ_Msk; /* Use flush to zero for very
  79                                        * small values. */
  80
  81     /* enable the FPU */
  82     SCB->CPACR  |= (0xf << 20);      // turn on CP10/11 for FP support on cores that implement it
  83
  84     /* copy initialised data from flash to RAM */
  85     memcpy(&_sdata, &_sidata, &_edata - &_sdata);
  86
  87     /* zero the BSS */
  88     memset(&_sbss, 0, &_ebss - &_sbss);
  89
  90     /* zero any 'fast' RAM that's been used */
  91     memset(&_sfast, 0, &_efast - &_sfast);
  92
  93     /* fill most of the IRQ/bootstrap stack with a watermark pattern so we can measure how much is used */
  94     /* leave a little space at the top in case memset() isn't a leaf with no locals */
  95     memset(&irq_stack, 0xa5, sizeof(irq_stack) - 64);
  96
  97     /* call main */
  98     (void)main();
  99 }
 100
 101 /**
 102  * Default handler for CPU exceptions.
 103  */
 104 static void default_cpu_handler(void)
 105 {
 106     for (;;) {
 107         ;
 108     }
 109 }
 110
 111 static void default_NMI_Handler()
 112 {
 113     default_cpu_handler();
 114 }
 115 static void default_HardFault_Handler()
 116 {
 117     default_cpu_handler();
 118 }
 119 static void default_MemManage_Handler()
 120 {
 121     default_cpu_handler();
 122 }
 123 static void default_BusFault_Handler()
 124 {
 125     default_cpu_handler();
 126 }
 127 static void default_UsageFault_Handler()
 128 {
 129     default_cpu_handler();
 130 }
 131 static void default_DebugMon_Handler()
 132 {
 133     default_cpu_handler();
 134 }
 135 static void default_vPortSVCHandler()
 136 {
 137     default_cpu_handler();
 138 }
 139 static void default_xPortPendSVHandler()
 140 {
 141     default_cpu_handler();
 142 }
 143 static void default_xPortSysTickHandler()
 144 {
 145     default_cpu_handler();
 146 }
 147
 148
 149 /** Prototype for optional exception vector handlers */
 150 #define HANDLER(_name) extern vector _name __attribute__((weak, alias("default_" #_name)))
 151
 152 /* standard CMSIS vector names */
 153 HANDLER(NMI_Handler);
 154 HANDLER(HardFault_Handler);
 155 HANDLER(MemManage_Handler);
 156 HANDLER(BusFault_Handler);
 157 HANDLER(UsageFault_Handler);
 158 HANDLER(DebugMon_Handler);
 159 /* these vectors point directly to the relevant FreeRTOS functions if they are defined */
 160 HANDLER(vPortSVCHandler);
 161 HANDLER(xPortPendSVHandler);
 162 HANDLER(xPortSysTickHandler);
 163
 164 /** CortexM3 vector table */
 165 struct cm3_vectors cpu_vectors __attribute((section(".cpu_vectors"))) =
 166 {
 167     .initial_stack = &irq_stack[sizeof(irq_stack)],
 168     .entry   = (vector *)_main,
 169     .vectors = {
 170         NMI_Handler,
 171         HardFault_Handler,
 172         MemManage_Handler,
 173         BusFault_Handler,
 174         UsageFault_Handler,
 175         0,
 176         0,
 177         0,
 178         0,
 179         vPortSVCHandler,
 180         DebugMon_Handler,   // Maybe
 181         0,
 182         xPortPendSVHandler,
 183         xPortSysTickHandler,
 184     }
 185 };
 186
 187 /**
 188  * @}
 189  */