#include <string.h>
#include <errno.h>
#include <stm32.h>
#include <sys/stat.h>
#include <gpio.h>
#include <stdio.h>

#define STDOUT_FILENO 1
#define STDIN_FILENO 0
#define STDERR_FILENO 2

#define USART_Mode_Rx_Tx (USART_CR1_RE | \
USART_CR1_TE)
#define USART_Enable USART_CR1_UE

#define USART_WordLength_8b 0x0000
#define USART_WordLength_9b USART_CR1_M

#define USART_Parity_No 0x0000
#define USART_Parity_Even USART_CR1_PCE
#define USART_Parity_Odd (USART_CR1_PCE | \
USART_CR1_PS)

#define USART_StopBits_1 0x0000
#define USART_StopBits_0_5 0x1000
#define USART_StopBits_2 0x2000
#define USART_StopBits_1_5 0x3000

#define USART_FlowControl_None 0x0000
#define USART_FlowControl_RTS USART_CR3_RTSE
#define USART_FlowControl_CTS USART_CR3_CTSE

#define HSI_HZ 16000000U
#define PCLK1_HZ HSI_HZ

uint32_t const baudrate = 9600U;

void setUp() {
	RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN | RCC_AHB1ENR_DMA1EN;
	RCC->APB1ENR |= RCC_APB1ENR_USART2EN;
	RCC->APB2ENR |= RCC_APB2ENR_SYSCFGEN;
	GPIOafConfigure(GPIOA,
			2,
			GPIO_OType_PP,
			GPIO_Fast_Speed,
			GPIO_PuPd_NOPULL,
			GPIO_AF_USART2);
	GPIOafConfigure(GPIOA,
			3,
			GPIO_OType_PP,
			GPIO_Fast_Speed,
			GPIO_PuPd_UP,
			GPIO_AF_USART2);
	USART2->CR1 = USART_CR1_RE | USART_CR1_TE;
	USART2->CR2 = 0;
	USART2->BRR = (PCLK1_HZ + (baudrate / 2U)) / baudrate;
	USART2->CR3 = USART_CR3_DMAT | USART_CR3_DMAR;
	DMA1_Stream6->CR = 4U << 25 |
		DMA_SxCR_PL_1 |
		DMA_SxCR_MINC |
		DMA_SxCR_DIR_0 |
		DMA_SxCR_TCIE;
	DMA1_Stream6->PAR = (uint32_t)&USART2->DR;
	DMA1_Stream5->CR = 4U << 25 |
		DMA_SxCR_PL_1 |
		DMA_SxCR_MINC |
		DMA_SxCR_TCIE;
	DMA1_Stream5->PAR = (uint32_t)&USART2->DR;
	DMA1->HIFCR = DMA_HIFCR_CTCIF6 |
		DMA_HIFCR_CTCIF5;
	NVIC_EnableIRQ(DMA1_Stream6_IRQn);
	NVIC_EnableIRQ(DMA1_Stream5_IRQn);
	USART2->CR1 |= USART_CR1_UE;

	__NOP();
}

void sendMessage(char* message) {
	DMA1_Stream6->M0AR = (uint32_t) message;
	DMA1_Stream6->NDTR = strlen(message);
	DMA1_Stream6->CR |= DMA_SxCR_EN;
}

int main() {
	setUp();
	sendMessage("Initialized\n\0");
}