musb_core.c 解析

最新推荐文章于 2024-07-13 08:00:00 发布

lamdoc

最新推荐文章于 2024-07-13 08:00:00 发布

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分类专栏： USB 文章标签： struct timer c table module list

本文链接：https://blog.youkuaiyun.com/lamdoc/article/details/8062386

本文详细探讨musb_core.c文件，它是USB通用接口musb模块的核心部分，涉及USB、musb、DMA及平台模块等多个组件。musb_init()函数初始化过程包括musb_driver结构体的musb_driver_name和fifo_mode设置。

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musb_core.c 是usb_general.c 调用进musb模块的核心函数，

里面有usb，musb，dma，platform模块等内容。

1. musb_init():

/* make us init after usbcore and i2c (transceivers, regulators, etc)
 * and before usb gadget and host-side drivers start to register
 */
fs_initcall(musb_init);

static int __init musb_init(void)
{
#ifdef CONFIG_USB_MUSB_HDRC_HCD
	if (usb_disabled())
		return 0;
#endif

	pr_info("%s: version " MUSB_VERSION ", "
#ifdef CONFIG_MUSB_PIO_ONLY               //这些宏由内核配置选项中来
		"pio"
#elif defined(CONFIG_USB_TI_CPPI_DMA)
		"cppi-dma"
#elif defined(CONFIG_USB_INVENTRA_DMA)
		"musb-dma"
#elif defined(CONFIG_USB_TUSB_OMAP_DMA)
		"tusb-omap-dma"
#elif defined(CONFIG_USB_CARTESIO_DMA)
		"pl080-dma"
#else
		"?dma?"
#endif
		", "
#ifdef CONFIG_USB_MUSB_OTG
		"otg (peripheral+host)"
#elif defined(CONFIG_USB_GADGET_MUSB_HDRC)
		"peripheral"
#elif defined(CONFIG_USB_MUSB_HDRC_HCD)
		"host"
#endif
		", debug=%d\n",
		musb_driver_name, musb_debug);
	return platform_driver_probe(&musb_driver, musb_probe);  //这里调用了platform 平台函数，注册进platform类型队列中。
}

musb_driver：

static struct platform_driver musb_driver = {
	.driver = {
		.name		= (char *)musb_driver_name, 
		.bus		= &platform_bus_type,   //platform bus类型
		.owner		= THIS_MODULE,
		.pm		= MUSB_DEV_PM_OPS,    //PM OPS， suspend+resume
	},
	.remove		= __exit_p(musb_remove),  
	.shutdown	= musb_shutdown,
};

1.1 musb_driver_name 定义：

#define MUSB_DRIVER_NAME "musb_hdrc"
const char musb_driver_name[] = MUSB_DRIVER_NAME;

1.2 MUSB_DEV_PM_OPS 定义：

#define MUSB_DEV_PM_OPS (&musb_dev_pm_ops)
#else
#define	MUSB_DEV_PM_OPS	NULL
#endif

static const struct dev_pm_ops musb_dev_pm_ops = {
	.suspend	= musb_suspend,
	.resume         = musb_resume_noirq,
};

static int musb_suspend(struct device *dev)

static int musb_suspend(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	unsigned long	flags;
	struct musb	*musb = dev_to_musb(&pdev->dev);

	if (!musb->clock)
		return 0;

	spin_lock_irqsave(&musb->lock, flags);

	if (is_peripheral_active(musb)) {
		/* FIXME force disconnect unless we know USB will wake
		 * the system up quickly enough to respond ...
		 */
	} else if (is_host_active(musb)) {
		/* we know all the children are suspended; sometimes
		 * they will even be wakeup-enabled.
		 */
	}

	musb_save_context(musb);

	if (musb->set_clock)
		musb->set_clock(musb->clock, 0);
	else
		clk_disable(musb->clock);
	spin_unlock_irqrestore(&musb->lock, flags);
	return 0;
}

static int musb_resume_noirq(struct device *dev):

static int musb_resume_noirq(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct musb	*musb = dev_to_musb(&pdev->dev);
#ifdef MUSB_RESTORE_REG
	int status;
#endif
	if (!musb->clock)
		return 0;

	if (musb->set_clock)
		musb->set_clock(musb->clock, 1);
	else
		clk_enable(musb->clock);

	musb_restore_context(musb);

#ifdef MUSB_RESTORE_REG
	status = musb_core_init(musb->is_multipoint
				? MUSB_CONTROLLER_MHDRC
				: MUSB_CONTROLLER_HDRC, musb);
	if (status < 0)
		return status;

	/* we need to apply the DEV_CTRL SESSION bit to initialize the VBUS.
	 * This should be generally called through root hub POWERON feature,
	 * but it is needed also  here if autosuspend is disabled.
         */
	musb_start(musb);

	/* wait for the connect interrupt */
	mdelay(200);
#endif
	return 0;
}

1.4 static int __exit musb_remove(struct platform_device *pdev)

static int __exit musb_remove(struct platform_device *pdev)
{
	struct musb	*musb = dev_to_musb(&pdev->dev);
	void __iomem	*ctrl_base = musb->ctrl_base;

	/* this gets called on rmmod.
	 *  - Host mode: host may still be active
	 *  - Peripheral mode: peripheral is deactivated (or never-activated)
	 *  - OTG mode: both roles are deactivated (or never-activated)
	 */
	musb_shutdown(pdev);
#ifdef CONFIG_USB_MUSB_HDRC_HCD
	if (musb->board_mode == MUSB_HOST)
		usb_remove_hcd(musb_to_hcd(musb));
#endif
	musb_writeb(musb->mregs, MUSB_DEVCTL, 0);
	musb_platform_exit(musb);
	musb_writeb(musb->mregs, MUSB_DEVCTL, 0);

	musb_free(musb);
	iounmap(ctrl_base);
	device_init_wakeup(&pdev->dev, 0);
#ifndef CONFIG_MUSB_PIO_ONLY
	pdev->dev.dma_mask = orig_dma_mask;
#endif
	return 0;
}

1.5 static void musb_shutdown(struct platform_device *pdev)

static void musb_shutdown(struct platform_device *pdev)
{
	struct musb	*musb = dev_to_musb(&pdev->dev);
	unsigned long	flags;

	spin_lock_irqsave(&musb->lock, flags);
	musb_platform_disable(musb);
	musb_generic_disable(musb);
	if (musb->clock)
		clk_put(musb->clock);
	spin_unlock_irqrestore(&musb->lock, flags);

	/* FIXME power down */
}

2. musb_cleanup():

static void __exit musb_cleanup(void)
{
	platform_driver_unregister(&musb_driver);
}
module_exit(musb_cleanup);

3. static int __init musb_probe(struct platform_device *pdev)

static int __init musb_probe(struct platform_device *pdev)
{
	struct device	*dev = &pdev->dev;
	int		irq = platform_get_irq(pdev, 0);
	int		status;
	struct resource	*iomem;
	void __iomem	*base;

	iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);  //获取 platform 资源
	if (!iomem || irq == 0)
		return -ENODEV;

	base = ioremap(iomem->start, resource_size(iomem));    //映射内存
	if (!base) {
		dev_err(dev, "ioremap failed\n");
		return -ENOMEM;
	}

#ifndef CONFIG_MUSB_PIO_ONLY
	/* clobbered by use_dma=n */
	orig_dma_mask = dev->dma_mask;         //如果内核配置了CONFIG_MUSB_PIO_ONLY,则屏蔽DMA
#endif
	status = musb_init_controller(dev, irq, base);   //这个才是主要的函数
	if (status < 0)
		iounmap(base);

	return status;
}

4. static int __init
musb_init_controller(struct