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/boot.h" 16 17 #include "pw_preprocessor/compiler.h" 18 #include "pw_sys_io_baremetal_lm3s6965evb/init.h" 19 #include "pw_toolchain/infinite_loop.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 // compile time but does NOT require it to be evaluated at compile time 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 // Force RCC to be at default at boot. 28 constexpr uint32_t kRccDefault = 0x078E3AD1U; 29 volatile uint32_t& rcc = *reinterpret_cast<volatile uint32_t*>(0x400FE070U); 30 rcc = kRccDefault; 31 constexpr uint32_t kRcc2Default = 0x07802810U; 32 volatile uint32_t& rcc2 = *reinterpret_cast<volatile uint32_t*>(0x400FE070U); 33 rcc2 = kRcc2Default; 34 } 35 pw_boot_PreStaticConstructorInit()36void pw_boot_PreStaticConstructorInit() {} 37 pw_boot_PreMainInit()38void pw_boot_PreMainInit() { pw_sys_io_lm3s6965evb_Init(); } 39 pw_boot_PostMain()40PW_NO_RETURN void pw_boot_PostMain() { 41 // QEMU requires a special command to tell the VM to shut down. 42 volatile uint32_t* aircr = (uint32_t*)(0xE000ED0CU); 43 *aircr = 0x5fa0004; 44 45 // In case main() returns, just sit here until the device is reset. 46 pw::InfiniteLoop(); 47 } 48