01_basicLinux内核模块-CSDN博客文章浏览阅读23次。环境ID=ubuntuMakefilemodules:clean:basic.creturn 0;运行效果。https://blog.csdn.net/m0_37132481/article/details/136157384?csdn_share_tail=%7B%22type%22%3A%22blog%22%2C%22rType%22%3A%22article%22%2C%22rId%22%3A%22136157384%22%2C%22source%22%3A%22m0_37132481%22%7Duart.c

root@T:/media/sf_D_DRIVE/kmodule/03_uart# cat uart.c
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/device.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/io.h>

#define TAG "HELLO# "

static void my_uart_stop_tx(struct uart_port *port)
{
        printk(TAG "%s\n", __func__);
}
static void echo_putchar(struct uart_port *port, u8 ch)
{
        /* write char output */
        printk("%c", ch);
        /* read char input */
        uart_insert_char(port, 0, 0, ch, 0);
        tty_flip_buffer_push(&port->state->port);
}
static void my_uart_start_tx(struct uart_port *port)
{
        printk(TAG "%s\n", __func__);
        u8 ch;
        u8 tx_ready = 1;

        uart_port_tx(port, ch, tx_ready, echo_putchar(port, ch));
}
static void my_uart_stop_rx(struct uart_port *port)
{
        printk(TAG "%s\n", __func__);
}

static unsigned int my_uart_tx_empty(struct uart_port *port)
{
        printk(TAG "%s\n", __func__);
        return 0;
}

/* no modem control lines */
static unsigned int my_uart_get_mctrl(struct uart_port *port)
{
        printk(TAG "%s\n", __func__);
        return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
}

static void my_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
        printk(TAG "%s\n", __func__);
}

static void my_uart_break_ctl(struct uart_port *port, int break_state)
{
        printk(TAG "%s\n", __func__);
}

static int my_uart_startup(struct uart_port *port)
{
        int ret = 0;
        printk(TAG "%s\n", __func__);
        return ret;
}

static void my_uart_shutdown(struct uart_port *port)
{
        printk(TAG "%s\n", __func__);
}

static void my_uart_set_termios(struct uart_port *port, struct ktermios *termios, const struct ktermios *old)
{
        printk(TAG "%s\n", __func__);
}

static const char *my_uart_type(struct uart_port *port)
{
        printk(TAG "%s\n", __func__);
        return port->type == PORT_21285 ? "my_uart_type" : NULL;
}

static void my_uart_release_port(struct uart_port *port)
{
        printk(TAG "%s\n", __func__);
}

static int my_uart_request_port(struct uart_port *port)
{
        printk(TAG "%s\n", __func__);
        return 0;
}

static void my_uart_config_port(struct uart_port *port, int flags)
{
        printk(TAG "%s\n", __func__);
        if (flags & UART_CONFIG_TYPE)
                port->type = PORT_21285;
}

/*
 * verify the new serial_struct (for TIOCSSERIAL).
 */
static int my_uart_verify_port(struct uart_port *port, struct serial_struct *ser)
{
        printk(TAG "%s\n", __func__);
        int ret = 0;
        return ret;
}

static const struct uart_ops my_uart_ops = {
        .tx_empty       = my_uart_tx_empty,
        .get_mctrl      = my_uart_get_mctrl,
        .set_mctrl      = my_uart_set_mctrl,
        .stop_tx        = my_uart_stop_tx,
        .start_tx       = my_uart_start_tx,
        .stop_rx        = my_uart_stop_rx,
        .break_ctl      = my_uart_break_ctl,
        .startup        = my_uart_startup,
        .shutdown       = my_uart_shutdown,
        .set_termios    = my_uart_set_termios,
        .type           = my_uart_type,
        .release_port   = my_uart_release_port,
        .request_port   = my_uart_request_port,
        .config_port    = my_uart_config_port,
        .verify_port    = my_uart_verify_port,
};

static struct uart_port my_uart_port = {
        .mapbase        = 0xaabbccdd,
        .iotype         = UPIO_MEM,
        .irq            = 0,
        .fifosize       = 16,
        .ops            = &my_uart_ops,
        .flags          = UPF_BOOT_AUTOCONF,
};

static struct uart_driver my_uart_reg = {
        .owner                  = THIS_MODULE,
        .driver_name            = "my_uart_driver",
        .dev_name               = "ttyMyUart",
        .major                  = 204,
        .minor                  = 4,
        .nr                     = 1,
};

static int __init my_uart_init(void)
{
        int ret;

        my_uart_port.dev = kzalloc(sizeof(*my_uart_port.dev), GFP_KERNEL);
        dev_set_name(my_uart_port.dev, "%s", "my_uart_device");
        ret = device_register(my_uart_port.dev);
        my_uart_port.dev = get_device(my_uart_port.dev);

        ret = uart_register_driver(&my_uart_reg);
        if (ret == 0)
                ret = uart_add_one_port(&my_uart_reg, &my_uart_port);

        printk("ret=%d\n", ret);
        return ret;
}

static void __exit my_uart_exit(void)
{
        uart_remove_one_port(&my_uart_reg, &my_uart_port);
        uart_unregister_driver(&my_uart_reg);

        device_unregister(my_uart_port.dev);
        kfree(my_uart_port.dev);
}

module_init(my_uart_init);
module_exit(my_uart_exit);

MODULE_LICENSE("GPL");

效果

 root@T:/media/sf_D_DRIVE/kmodule/03_uart# ls /dev/ttyMyUart0
/dev/ttyMyUart0