#include "uart.h"
#include <errno.h>
#include <libopencm3/cm3/nvic.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/usart.h>
#include <stdio.h>

int _write(int file, char *ptr, int len);

void usart_setup(void) {
    /* Setup GPIO pin GPIO_USART1_RE_TX on GPIO port B for transmit. */
    gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART1_TX);

    /* Setup UART parameters. */
    usart_set_baudrate(USART1, 115200);
    usart_set_databits(USART1, 8);
    usart_set_stopbits(USART1, USART_STOPBITS_1);
    usart_set_parity(USART1, USART_PARITY_NONE);
    usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE);
    usart_set_mode(USART1, USART_MODE_TX);

    /* Finally enable the USART. */
    usart_enable(USART1);
}

int _write(int file, char *ptr, int len) {
    int i;

    if (file == 1) {
        for (i = 0; i < len; i++) usart_send_blocking(USART1, ptr[i]);
        return i;
    }

    errno = EIO;
    return -1;
}