1 // Copyright 2020 The Pigweed Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not 4 // use this file except in compliance with the License. You may obtain a copy of 5 // the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 12 // License for the specific language governing permissions and limitations under 13 // the License. 14 15 #include "pw_boot_armv7m/boot.h" 16 17 #include "pw_malloc/malloc.h" 18 #include "pw_preprocessor/compiler.h" 19 #include "pw_sys_io_baremetal_stm32f429/init.h" 20 21 // Note that constexpr is used inside of this function instead of using a static 22 // constexpr or declaring it outside of this function in an anonymous namespace, 23 // because constexpr makes it available for the compiler to evaluate during 24 // copmile time but does NOT require it to be evaluated at compile team and we 25 // have to be incredibly careful that this does not end up in the .data section. pw_boot_PreStaticMemoryInit()26void pw_boot_PreStaticMemoryInit() { 27 // TODO(pwbug/17): Optionally enable Replace when Pigweed config system is 28 // added. 29 #if PW_ARMV7M_ENABLE_FPU 30 // Enable FPU if built using hardware FPU instructions. 31 // CPCAR mask that enables FPU. (ARMv7-M Section B3.2.20) 32 constexpr uint32_t kFpuEnableMask = (0xFu << 20); 33 34 // Memory mapped register to enable FPU. (ARMv7-M Section B3.2.2, Table B3-4) 35 volatile uint32_t& arm_v7m_cpacr = 36 *reinterpret_cast<volatile uint32_t*>(0xE000ED88u); 37 arm_v7m_cpacr |= kFpuEnableMask; 38 39 // Ensure the FPU configuration is committed and enabled before continuing and 40 // potentially executing any FPU instructions, however rare that may be during 41 // startup. 42 asm volatile( 43 " dsb \n" 44 " isb \n" 45 // clang-format off 46 : /*output=*/ 47 : /*input=*/ 48 : /*clobbers=*/"memory" 49 // clang-format on 50 ); 51 #endif // PW_ARMV7M_ENABLE_FPU 52 } 53 pw_boot_PreStaticConstructorInit()54void pw_boot_PreStaticConstructorInit() { 55 #if PW_MALLOC_ACTIVE 56 pw_MallocInit(); 57 #endif // PW_MALLOC_ACTIVE 58 } 59 pw_boot_PreMainInit()60void pw_boot_PreMainInit() { pw_sys_io_Init(); } 61 pw_boot_PostMain()62PW_NO_RETURN void pw_boot_PostMain() { 63 // In case main() returns, just sit here until the device is reset. 64 while (true) { 65 } 66 PW_UNREACHABLE; 67 } 68