生成一段使用Linkedlist的DMA完整驱动代码

以下是一个使用Linkedlist的DMA完整驱动代码的示例：

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/dmaengine.h>
#include <linux/slab.h>

#define DRIVER_NAME "my_dma_driver"

struct my_dma_device {
    struct dma_chan *dma_chan;
    dma_addr_t dma_addr;
    size_t dma_size;
    struct scatterlist *sg;
};

static int my_dma_probe(struct platform_device *pdev)
{
    struct my_dma_device *my_dma_dev;
    struct resource *res;
    int ret;

    printk(KERN_INFO "my_dma_driver: probing...\n");

    // Allocate memory for the device structure
    my_dma_dev = kzalloc(sizeof(*my_dma_dev), GFP_KERNEL);
    if (!my_dma_dev) {
        printk(KERN_ERR "my_dma_driver: failed to allocate memory for device\n");
        return -ENOMEM;
    }

    // Get the resource for the DMA controller
    res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
    if (!res) {
        printk(KERN_ERR "my_dma_driver: failed to get resource for DMA controller\n");
        ret = -ENODEV;
        goto err_free_dev;
    }

    // Allocate a DMA channel
    my_dma_dev->dma_chan = dma_request_slave_channel(&pdev->dev, "dma0");
    if (!my_dma_dev->dma_chan) {
        printk(KERN_ERR "my_dma_driver: failed to allocate DMA channel\n");
        ret = -EBUSY;
        goto err_free_dev;
    }

    // Allocate a buffer to transfer data
    my_dma_dev->dma_size = PAGE_SIZE;
    my_dma_dev->sg = kmalloc(sizeof(*my_dma_dev->sg), GFP_KERNEL);
    if (!my_dma_dev->sg) {
        printk(KERN_ERR "my_dma_driver: failed to allocate scatterlist\n");
        ret = -ENOMEM;
        goto err_free_chan;
    }
    sg_init_table(my_dma_dev->sg, 1);
    ret = dma_map_sg(&pdev->dev, my_dma_dev->sg, 1, DMA_TO_DEVICE);
    if (ret != 1) {
        printk(KERN_ERR "my_dma_driver: failed to map scatterlist\n");
        ret = -ENOMEM;
        goto err_free_sg;
    }
    my_dma_dev->dma_addr = sg_dma_address(my_dma_dev->sg);

    // Save the device structure in the platform data
    platform_set_drvdata(pdev, my_dma_dev);

    printk(KERN_INFO "my_dma_driver: probed\n");
    return 0;

err_free_sg:
    kfree(my_dma_dev->sg);
err_free_chan:
    dma_release_channel(my_dma_dev->dma_chan);
err_free_dev:
    kfree(my_dma_dev);
    return ret;
}

static int my_dma_remove(struct platform_device *pdev)
{
    struct my_dma_device *my_dma_dev = platform_get_drvdata(pdev);

    printk(KERN_INFO "my_dma_driver: removing...\n");

    // Unmap the scatterlist
    dma_unmap_sg(&pdev->dev, my_dma_dev->sg, 1, DMA_TO_DEVICE);

    // Free the scatterlist and buffer
    kfree(my_dma_dev->sg);

    // Release the DMA channel
    dma_release_channel(my_dma_dev->dma_chan);

    // Free the device structure
    kfree(my_dma_dev);

    printk(KERN_INFO "my_dma_driver: removed\n");
    return 0;
}

static struct platform_driver my_dma_driver = {
    .probe = my_dma_probe,
    .remove = my_dma_remove,
    .driver = {
        .name = DRIVER_NAME,
        .owner = THIS_MODULE,
    },
};

static int __init my_dma_init(void)
{
    int ret;

    printk(KERN_INFO "my_dma_driver: initializing...\n");

    // Register the platform driver
    ret = platform_driver_register(&my_dma_driver);
    if (ret) {
        printk(KERN_ERR "my_dma_driver: failed to register platform driver\n");
        return ret;
    }

    printk(KERN_INFO "my_dma_driver: initialized\n");
    return 0;
}

static void __exit my_dma_exit(void)
{
    printk(KERN_INFO "my_dma_driver: exiting...\n");

    // Unregister the platform driver
    platform_driver_unregister(&my_dma_driver);

    printk(KERN_INFO "my_dma_driver: exited\n");
}

module_init(my_dma_init);
module_exit(my_dma_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Author Name");
MODULE_DESCRIPTION("A simple DMA driver using Linkedlist for Linux");