Files
ttt2/system/src/cortexm/_initialize_hardware.c
Wolfgang Hottgenroth 27f62c4c27 initial
2017-05-26 18:45:18 +02:00

88 lines
2.6 KiB
C

//
// This file is part of the µOS++ III distribution.
// Copyright (c) 2014 Liviu Ionescu.
//
// ----------------------------------------------------------------------------
#include "cmsis_device.h"
// ----------------------------------------------------------------------------
extern unsigned int __vectors_start;
// Forward declarations.
void
__initialize_hardware_early(void);
void
__initialize_hardware(void);
// ----------------------------------------------------------------------------
// This is the early hardware initialisation routine, it can be
// redefined in the application for more complex cases that
// require early inits (before BSS init).
//
// Called early from _start(), right before data & bss init.
//
// After Reset the Cortex-M processor is in Thread mode,
// priority is Privileged, and the Stack is set to Main.
void
__attribute__((weak))
__initialize_hardware_early(void)
{
// Call the CSMSIS system initialisation routine.
SystemInit();
#if defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7EM__)
// Set VTOR to the actual address, provided by the linker script.
// Override the manual, possibly wrong, SystemInit() setting.
SCB->VTOR = (uint32_t)(&__vectors_start);
#endif
// The current version of SystemInit() leaves the value of the clock
// in a RAM variable (SystemCoreClock), which will be cleared shortly,
// so it needs to be recomputed after the RAM initialisations
// are completed.
#if defined(OS_INCLUDE_STARTUP_INIT_FP) || (defined (__VFP_FP__) && !defined (__SOFTFP__))
// Normally FP init is done by SystemInit(). In case this is not done
// there, it is possible to force its inclusion by defining
// OS_INCLUDE_STARTUP_INIT_FP.
// Enable the Cortex-M4 FPU only when -mfloat-abi=hard.
// Code taken from Section 7.1, Cortex-M4 TRM (DDI0439C)
// Set bits 20-23 to enable CP10 and CP11 coprocessor
SCB->CPACR |= (0xF << 20);
#endif // (__VFP_FP__) && !(__SOFTFP__)
#if defined(OS_DEBUG_SEMIHOSTING_FAULTS)
SCB->SHCSR |= SCB_SHCSR_USGFAULTENA_Msk;
#endif
}
// This is the second hardware initialisation routine, it can be
// redefined in the application for more complex cases that
// require custom inits (before constructors), otherwise these can
// be done in main().
//
// Called from _start(), right after data & bss init, before
// constructors.
void
__attribute__((weak))
__initialize_hardware(void)
{
// Call the CSMSIS system clock routine to store the clock frequency
// in the SystemCoreClock global RAM location.
SystemCoreClockUpdate();
}
// ----------------------------------------------------------------------------