linux XDMA驱动程序代码

下面是一个简单的 Linux XDMA 驱动程序的代码示例：

#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/io.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>

// XDMA 寄存器的偏移量
#define XDMA_CTRL_OFFSET 0x00
#define XDMA_STATUS_OFFSET 0x04
#define XDMA_SRC_ADDR_OFFSET 0x08
#define XDMA_DEST_ADDR_OFFSET 0x0C
#define XDMA_TRANSFER_LEN_OFFSET 0x10

// XDMA 寄存器的位域定义
#define XDMA_CTRL_START_BIT 0
#define XDMA_CTRL_RESET_BIT 1
#define XDMA_STATUS_DONE_BIT 0

struct xdma_device {
    struct platform_device *pdev;
    void __iomem *regs;
    dma_addr_t src_phys;
    dma_addr_t dest_phys;
    size_t len;
    struct dma_chan *chan;
};

static void xdma_transfer_complete(void *arg)
{
    struct xdma_device *dev = arg;
    unsigned long flags;

    spin_lock_irqsave(&dev->chan->lock, flags);
    dma_cookie_complete(dev->chan, dev->cookie);
    spin_unlock_irqrestore(&dev->chan->lock, flags);
}

static int xdma_transfer(struct xdma_device *dev)
{
    int ret;

    ret = dmaengine_prep_dma_memcpy(dev->chan, dev->dest_phys,
                                    dev->src_phys, dev->len,
                                    DMA_PREP_INTERRUPT |
                                    DMA_CTRL_ACK);
    if (ret < 0) {
        dev_err(&dev->pdev->dev, "dmaengine_prep_dma_memcpy failed: %d\n", ret);
        return ret;
    }

    dev->cookie = dmaengine_submit(dev->chan, &desc);
    dma_async_issue_pending(dev->chan);

    return 0;
}

static int xdma_probe(struct platform_device *pdev)
{
    struct device *dev = &pdev->dev;
    struct xdma_device *xdma;
    struct resource *res;
    int ret;

    xdma = devm_kzalloc(dev, sizeof(*xdma), GFP_KERNEL);
    if (!xdma)
        return -ENOMEM;

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    xdma->regs = devm_ioremap_resource(dev, res);
    if (IS_ERR(xdma->regs))
        return PTR_ERR(xdma->regs);

    xdma->src_phys = dma_map_single(dev, xdma->src, xdma->len, DMA_TO_DEVICE);
    if (dma_mapping_error(dev, xdma->src_phys)) {
        dev_err(dev, "dma_map_single failed for source\n");
        return -ENOMEM;
    }

    xdma->dest_phys = dma_map_single(dev, xdma->dest, xdma->len, DMA_FROM_DEVICE);
    if (dma_mapping_error(dev, xdma->dest_phys)) {
        dev_err(dev, "dma_map_single failed for destination\n");
        ret = -ENOMEM;
        goto unmap_src;
    }

    xdma->chan = dma_request_chan(dev, "dma0");
    if (IS_ERR(xdma->chan)) {
        dev_err(dev, "dma_request_chan failed\n");
        ret = PTR_ERR(xdma->chan);
        goto unmap_dest;
    }

    ret = xdma_transfer(xdma);
    if (ret < 0) {
        dev_err(dev, "xdma_transfer failed: %d\n", ret);
        goto release_chan;
    }

    return 0;

release_chan:
    dma_release_channel(xdma->chan);
unmap_dest:
    dma_unmap_single(dev, xdma->dest_phys, xdma->len, DMA_FROM_DEVICE);
unmap_src:
    dma_unmap_single(dev, xdma->src_phys, xdma->len, DMA_TO_DEVICE);

    return ret;
}

static int xdma_remove(struct platform_device *pdev)
{
    struct xdma_device *xdma = platform_get_drvdata(pdev);

    dmaengine_terminate_all(xdma->chan);
    dma_release_channel(xdma->chan);
    dma_unmap_single(&pdev->dev, xdma->dest_phys, xdma->len, DMA_FROM_DEVICE);
    dma_unmap_single(&pdev->dev, xdma->src_phys, xdma->len, DMA_TO_DEVICE);

    return 0;
}

static const struct of_device_id xdma_of_match[] = {
    { .compatible = "xlnx,axi-dma-1.00.a", },
    { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, xdma_of_match);

static struct platform_driver xdma_driver = {
    .driver = {
        .name = "xdma",
        .of_match_table = xdma_of_match,
    },
    .probe = xdma_probe,
    .remove = xdma_remove,
};

module_platform_driver(xdma_driver);

MODULE_AUTHOR("Your Name");
MODULE_DESCRIPTION("Simple XDMA Driver");
MODULE_LICENSE("GPL");

请注意，上述代码只是一个简单的示例，可能需要针对您的特定硬件进行修改和调整。建议您仔细阅读 Linux DMA 引擎的文档以及您的硬件的数据手册。