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// See LICENSE for license details.
#include "femto.h"
enum {
/* UART Registers */
UART_REG_TXFIFO = 0,
UART_REG_RXFIFO = 1,
UART_REG_TXCTRL = 2,
UART_REG_RXCTRL = 3,
UART_REG_IE = 4,
UART_REG_IP = 5,
UART_REG_DIV = 6,
/* TXCTRL register */
UART_TXEN = 1,
UART_TXSTOP = 2,
/* RXCTRL register */
UART_RXEN = 1,
/* IP register */
UART_IP_TXWM = 1,
UART_IP_RXWM = 2
};
static volatile int *uart;
static void sifive_uart_init()
{
uart = (int *)(void *)getauxval(SIFIVE_UART0_CTRL_ADDR);
uint32_t uart_freq = getauxval(UART0_CLOCK_FREQ);
uint32_t baud_rate = getauxval(UART0_BAUD_RATE);
uint32_t divisor = uart_freq / baud_rate - 1;
uart[UART_REG_DIV] = divisor;
uart[UART_REG_TXCTRL] = UART_TXEN;
uart[UART_REG_RXCTRL] = UART_RXEN;
uart[UART_REG_IE] = 0;
}
static int sifive_uart_getchar()
{
int ch = uart[UART_REG_RXFIFO];
if (ch < 0) return -1;
return ch;
}
static int sifive_uart_putchar(int ch)
{
while (uart[UART_REG_TXFIFO] < 0);
return uart[UART_REG_TXFIFO] = ch & 0xff;
}
console_device_t console_sifive_uart = {
sifive_uart_init,
sifive_uart_getchar,
sifive_uart_putchar
};
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