linux 串口 dma

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/tty.h>
#include <linux/tty_serial.h>
#include <linux/serial_core.h>

static int __init serial_dma_init(void) {
    struct uart_8250_port *up;
    struct uart_8250_uart *uart;

    // 获取UART端口
    up = &uart_ports[0];
    uart = &up->uart;

    // 配置DMA
    uart->dma = &dma_channel;
    uart->dmaflags = UP_DMA_MODE;
    uart->dma_rx_buf = dma_alloc_coherent(NULL, RX_BUF_SIZE, &uart->dma_rx_addr, GFP_KERNEL);
    uart->dma_tx_buf = dma_alloc_coherent(NULL, TX_BUF_SIZE, &uart->dma_tx_addr, GFP_KERNEL);

    // 启用DMA
    uart->flags |= UP_DMA;

    return 0;
}

static void __exit serial_dma_exit(void) {
    struct uart_8250_port *up;
    struct uart_8250_uart *uart;

    up = &uart_ports[0];
    uart = &up->uart;

    // 禁用DMA
    uart->flags &= ~UP_DMA;

    // 释放DMA缓冲区
    dma_free_coherent(NULL, RX_BUF_SIZE, uart->dma_rx_buf, uart->dma_rx_addr);
    dma_free_coherent(NULL, TX_BUF_SIZE, uart->dma_tx_buf, uart->dma_tx_addr);
}

module_init(serial_dma_init);
module_exit(serial_dma_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Serial DMA Example");
MODULE_AUTHOR("Your Name");