From 9f28e53c71d28d04e2775c59944d2887a99f1e86 Mon Sep 17 00:00:00 2001 From: Josh Rahm Date: Sun, 22 Nov 2020 01:06:30 -0700 Subject: Large reorganization. What was in core/ is now moved to arch/stm34l4xxx/peripherals. This new directory is *supposed to* to contain raw header files defining just the pertinent register structures for the various peripherals. Peripheral management belongs somewhere in the new `kern/..` directories. This is not completely the case at the moment, so more refactoring needs to be done. What was sitting in the root has now been moved into the kern/ directory. The kern/ directory is to contain everything else other than raw device register definitions. The root of the kern/ tree is reserved for standard library-esque headers. The kern/ directory contains management systems for that peripheral. (At the moment DMA is the only peripheral with a decent management system.) Preferably these peripheral systems should only include their correlating header in arch/stm34l4xxx/peripherals, and use other management systems for handling other peripherals rather than manipulating their raw registers directly. (Though this ideal will require much more critical mass of management systems.) --- 02-usart/src/arch/stm32l4xxx/peripherals/init.c | 49 +++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 02-usart/src/arch/stm32l4xxx/peripherals/init.c (limited to '02-usart/src/arch/stm32l4xxx/peripherals/init.c') diff --git a/02-usart/src/arch/stm32l4xxx/peripherals/init.c b/02-usart/src/arch/stm32l4xxx/peripherals/init.c new file mode 100644 index 0000000..47bfaa5 --- /dev/null +++ b/02-usart/src/arch/stm32l4xxx/peripherals/init.c @@ -0,0 +1,49 @@ +#include "arch.h" +#include "arch/stm32l4xxx/peripherals/system.h" + +/* Forward-declare the main function. This is implemented in main.c. */ +void main(); + +/* These are defined in the linker script. */ + +#ifdef ARCH_STM32L4 +extern uint32_t INIT_DATA_VALUES; +extern uint32_t DATA_SEGMENT_START; +extern uint32_t DATA_SEGMENT_STOP; +extern uint32_t BSS_START; +extern uint32_t BSS_END; + +/* + * Runs before main. Initializes the data and bss segments by loading them + * into memory. + */ +_Noreturn void on_reset() +{ + uint32_t* src; + uint32_t* dest; + + src = &INIT_DATA_VALUES; + dest = &DATA_SEGMENT_START; + + /* Copy the values from flash into the data segment. */ + while (dest != &DATA_SEGMENT_STOP) { + *(dest++) = *(src++); + } + + /* Everything in the BSS segment is set to zero. */ + dest = &BSS_START; + while (dest != &BSS_END) { + *(dest++) = 0; + } + + /* Set the vector offset table to be at the start + * of FLASH memory. */ + SCB.vto_r = 0x08000000; + + /* Jump to main. */ + main(); + + for(;;); +} + +#endif /* ARCH_STM32L4 */ -- cgit