rt-thread/bsp/ultrarisc/drivers/drv_uart.c

/*
 * Copyright (c) 2006-2025 RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2025-05-28     ZhangJing    Porting to ultrarisc dp1000
 */

#include <rthw.h>
#include <rtdevice.h>
#include <rtthread.h>

#include "board.h"
#include "drv_uart.h"

#include <stdio.h>
#ifdef RT_USING_SMART
    #include <ioremap.h>
#endif
#include "sbi.h"

struct device_uart
{
    rt_ubase_t hw_base;
    rt_uint32_t irqno;
};

#ifdef BSP_USING_UART0
    void *uart0_base = (void *)UART0_BASE_ADDR;
    struct rt_serial_device serial0;
    struct device_uart uart0;

    #define UART0_CLK        (UART0_REFERENCE_CLOCK)
    #define UART0_BAUDRATE   (UART0_DEFAULT_BAUDRATE)
#endif

#define UART_REFERENCE_CLOCK (UART0_CLK)
#define REG_SHIFT            (1 << UART0_REG_SHIFT)
#define write8_uart(base,idx, value)  __raw_writeb(((rt_uint8_t)value), (void*)((size_t)base + (idx*REG_SHIFT)))
#define read8_uart(base,idx)  __raw_readb((void*)((size_t)base + (idx*REG_SHIFT)))

static rt_err_t _uart_configure(struct rt_serial_device *serial, struct serial_configure *cfg)
{
    struct device_uart *uart = (struct device_uart *)serial->parent.user_data;
    rt_uint32_t div = UART_REFERENCE_CLOCK / (cfg->baud_rate  * 16);
    rt_uint32_t ier = read8_uart(uart->hw_base, UART_IER);

    write8_uart(uart->hw_base, UART_IER, 0x00);
    write8_uart(uart->hw_base, UART_LCR, UART_LCR_BAUD_LATCH);

    /* LSB */
    write8_uart(uart->hw_base, 0, div & 0xff);
    /* MSB */
    write8_uart(uart->hw_base, 1, (div >> 8) & 0xff);

    /* set word length to 8 bits, no parity */
    write8_uart(uart->hw_base, UART_LCR, UART_LCR_EIGHT_BITS);

    write8_uart(uart->hw_base, UART_FCR, UART_FCR_FIFO_ENABLE | UART_FCR_FIFO_CLEAR);
    write8_uart(uart->hw_base, UART_IER, ier);
    return (RT_EOK);
}

static rt_err_t _uart_control(struct rt_serial_device *serial, int cmd, void *arg)
{
    struct device_uart *uart = (struct device_uart *)serial->parent.user_data;

    switch (cmd)
    {
    case RT_DEVICE_CTRL_CLR_INT:
        if ((size_t)arg == RT_DEVICE_FLAG_INT_RX)
        {
            rt_uint8_t value = read8_uart(uart->hw_base, UART_IER);
            write8_uart(uart->hw_base, UART_IER, value & ~UART_IER_RX_ENABLE);
        }
        break;

    case RT_DEVICE_CTRL_SET_INT:
        if ((size_t)arg == RT_DEVICE_FLAG_INT_RX)
        {
            rt_uint8_t value = read8_uart(uart->hw_base, UART_IER);
            write8_uart(uart->hw_base, UART_IER, value | UART_IER_RX_ENABLE);
        }
        break;
    }

    return (RT_EOK);
}

static int _uart_putc(struct rt_serial_device *serial, char c)
{
    struct device_uart *uart;
    uart = (struct device_uart *)serial->parent.user_data;

    /* wait for Transmit Holding Empty to be set in LSR. */
    while ((read8_uart(uart->hw_base, UART_LSR) & UART_LSR_TX_IDLE) == 0)
        ;
    write8_uart(uart->hw_base, UART_THR, c);

    return (1);
}

static int _uart_getc(struct rt_serial_device *serial)
{
    struct device_uart *uart;
    volatile rt_uint32_t lsr;
    int ch = -1;

    uart = (struct device_uart *)serial->parent.user_data;
    lsr = read8_uart(uart->hw_base, UART_LSR);

    if (lsr & UART_LSR_RX_READY)
    {
        ch = read8_uart(uart->hw_base, UART_RHR);
    }
    return ch;
}

const struct rt_uart_ops _uart_ops =
{
    _uart_configure,
    _uart_control,
    _uart_putc,
    _uart_getc,
    /* TODO: add DMA support */
    RT_NULL
};

static void rt_hw_uart_isr(int irqno, void *param)
{
    rt_ubase_t level = rt_hw_interrupt_disable();

    struct rt_serial_device *serial = (struct rt_serial_device *)param;
    struct device_uart *uart = (struct device_uart *)serial->parent.user_data;

    if ((read8_uart(uart->hw_base, UART_LSR) & UART_LSR_RX_READY) != 0)
    {
        rt_hw_serial_isr(serial, RT_SERIAL_EVENT_RX_IND);
    }

    rt_hw_interrupt_enable(level);
    return;
}

/*
 * UART Initiation
 */
int rt_hw_uart_init(void)
{
    struct rt_serial_device *serial;
    struct device_uart *uart;
    struct serial_configure config = RT_SERIAL_CONFIG_DEFAULT;
    char ch;
#ifdef BSP_USING_UART0
    /* register device */
    serial = &serial0;
    uart = &uart0;

    serial->ops = &_uart_ops;
    serial->config = config;
    serial->config.baud_rate = UART0_BAUDRATE;
    uart->hw_base = (rt_ubase_t)uart0_base;
#ifdef RT_USING_SMART
    uart->hw_base = (rt_ubase_t)rt_ioremap((void *)uart0_base, 0x1000);
#endif
    uart->irqno = UART0_IRQ_BASE;
    /* disable all uart irqs */
    write8_uart(uart->hw_base, UART_IER, 0);
    /* wait for Transmit Holding Empty to be set in LSR. */
    while ((read8_uart(uart->hw_base, UART_LSR) & UART_LSR_TX_IDLE) == 0)
        ;

    while ((read8_uart(uart->hw_base, UART_LSR) & UART_LSR_RX_READY) != 0)
    {
        ch = read8_uart(uart->hw_base, UART_RHR);
    }

    rt_hw_serial_register(serial,
                          RT_CONSOLE_DEVICE_NAME,
                          RT_DEVICE_FLAG_STREAM | RT_DEVICE_FLAG_RDWR | RT_DEVICE_FLAG_INT_RX,
                          uart);
    rt_hw_interrupt_install(uart->irqno, rt_hw_uart_isr, serial, RT_CONSOLE_DEVICE_NAME);
    rt_hw_interrupt_umask(uart->irqno);
#endif
}