AR9344 5G网卡初始化

AR9344芯片中5G网卡是通过AHB总线连接在SOC中的.还有一个2.4G的无线网卡是挂在PCI总线上的
在ath9k驱动insmod时首先调用的是ath9k_init(void)；代码如下:

static int __init ath9k_init(void)
{
    int error;

    error = ath_ahb_init(); //这是是初始化AHB总线上的网卡设备的
    if (error < 0) {
        error = -ENODEV;
        goto err_out;
    }

    error = ath_pci_init(); //初始化PCI总线的网卡设备
    if (error < 0) {
        pr_err("No PCI devices found, driver not installed\n");
        error = -ENODEV;
        goto err_ahb_exit;
    }

    return 0;

 err_ahb_exit:
    ath_ahb_exit();
 err_out:
    return error;
}
module_init(ath9k_init);

通过上面的代码我们知道insmod ath9k驱动时会分别初始化AHB和PCI总线的网卡设备.
我们再看看AHB初始化时会做什么操作:

int ath_ahb_init(void)
{
    return platform_driver_register(&ath_ahb_driver);
}

其实就是通过函数platform_driver_register注册ahb驱动.
再看看ath_ahb_driver:

static struct platform_driver ath_ahb_driver = {
    .probe = ath_ahb_probe,
    .remove = ath_ahb_remove,
    .driver        = {
        .name    = "ath9k",
    },
    .id_table = ath9k_platform_id_table,
};

我们主要关注ath_ahb_probe函数, 在注册完成后会系统会自动调用它.
ath_ahb_remove函数会在unregister时候调用.

static int ath_ahb_probe(struct platform_device *pdev)
{
    void __iomem *mem;
    struct ath_softc *sc; //atheros用于硬件和mac层交互的中间载体.后面我们会单独分析改结构
    struct ieee80211_hw *hw; //mac80211层中代表硬件的信息和状态.后面会分析.
    struct resource *res;
    const struct platform_device_id *id = platform_get_device_id(pdev);
    int irq;
    int ret = 0;
    struct ath_hw *ah;
    char hw_name[64];

    if (!dev_get_platdata(&pdev->dev)) {
        dev_err(&pdev->dev, "no platform data specified\n");
        return -EINVAL;
    }

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (res == NULL) {
        dev_err(&pdev->dev, "no memory resource found\n");
        return -ENXIO;
    }

    mem = devm_ioremap_nocache(&pdev->dev, res->start, resource_size(res));
    if (mem == NULL) {
        dev_err(&pdev->dev, "ioremap failed\n");
        return -ENOMEM;
    }

    res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);//获取设备irq线
    if (res == NULL) {
        dev_err(&pdev->dev, "no IRQ resource found\n");
        return -ENXIO;
    }

    irq = res->start;

    ath9k_fill_chanctx_ops();
    hw = ieee80211_alloc_hw(sizeof(struct ath_softc), &ath9k_ops);//分配mac层硬件相关信息和状态结构体
    if (hw == NULL) {
        dev_err(&pdev->dev, "no memory for ieee80211_hw\n");
        return -ENOMEM;
    }

    SET_IEEE80211_DEV(hw, &pdev->dev);
    platform_set_drvdata(pdev, hw);

    sc = hw->priv;
    sc->hw = hw;
    sc->dev = &pdev->dev;
    sc->mem = mem;
    sc->irq = irq;

    ret = request_irq(irq, ath_isr, IRQF_SHARED, "ath9k", sc);//注册中断号
    if (ret) {
        dev_err(&pdev->dev, "request_irq failed\n");
        goto err_free_hw;
    }

    ret = ath9k_init_device(id->driver_data, sc, &ath_ahb_bus_ops);
    if (ret) {
        dev_err(&pdev->dev, "failed to initialize device\n");
        goto err_irq;
    }

    ah = sc->sc_ah;
    ath9k_hw_name(ah, hw_name, sizeof(hw_name));
    printk("carson[%s:%d], irq=%d\n", __func__, __LINE__, irq);
    wiphy_info(hw->wiphy, "%s mem=0x%lx, irq=%d\n",
           hw_name, (unsigned long)mem, irq);

    return 0;

 err_irq:
    free_irq(irq, sc);
 err_free_hw:
    ieee80211_free_hw(hw);
    return ret;
}

上面即是AHB驱动注册是的相关操作包括: 请求设备的IO内存,irq号等.分配ieee80211_hw结构.
我们先看看相关的结构体分别代码什么意思,再来分析上面的代码.