Chinaunix首页 | 论坛 | 博客
  • 博客访问: 2002469
  • 博文数量: 505
  • 博客积分: 1552
  • 博客等级: 上尉
  • 技术积分: 2524
  • 用 户 组: 普通用户
  • 注册时间: 2007-09-23 18:24
文章分类

全部博文(505)

文章存档

2019年(12)

2018年(15)

2017年(1)

2016年(17)

2015年(14)

2014年(93)

2013年(233)

2012年(108)

2011年(1)

2009年(11)

分类:

2012-10-23 10:08:49

原文地址:OTG驱动分析(二) 作者:garyybl

上回介绍了OTG功能的 OTG部分驱动,本片分析OTG功能的从设备部分驱动。从设备的注册过程和OTG的一样,首先注册设备。
流程是:
1. 定义platform_device结构。
2. 定义platform_device下的struct resource设备资源结构
3. 定义 platform_device下的DEV设备下的平台私有数据(就是该设备私有的数据)
4. 调用platform_device_register将platform_device结构
注册上面4个过程调用结束后,设备的信息就被注册到系统中,等待驱动的使用 下面是按照上面顺序贴出代码
 
定义platform_device结构

static struct platform_device __maybe_unused dr_udc_device = {
    . name = "fsl-usb2-udc" ,
    . id = - 1,
    . dev = {
        . release = dr_udc_release,
        . dma_mask = & dr_udc_dmamask,
        . coherent_dma_mask = 0xffffffff,
    } ,
    . resource = otg_resources,
    . num_resources = ARRAY_SIZE( otg_resources) ,
} ;

我们可以看到resource和OTG的resource一样,使用的都是OTG那部分资源

定义platform_device下的struct resource设备资源结构

static struct resource otg_resources[ ] = {
    [ 0] = {
     . start = ( u32) ( USB_OTGREGS_BASE) ,
     . end = ( u32) ( USB_OTGREGS_BASE + 0x1ff) ,
     . flags = IORESOURCE_MEM,
     } ,
    [ 1] = {
     . start = MXC_INT_USB_OTG,
     . flags = IORESOURCE_IRQ,
     } ,
} ;


定义platform_device下的DEV设备下的平台私有数据(就是该设备私有的数据)

 

 

static struct fsl_usb2_platform_data __maybe_unused dr_utmi_config = {
    . name = "DR" ,
    . platform_init = usbotg_init,
    . platform_uninit = usbotg_uninit,
    . phy_mode = FSL_USB2_PHY_UTMI_WIDE,
    . power_budget = 500,         /* via RT9706 */
    . gpio_usb_active = gpio_usbotg_utmi_active,
    . gpio_usb_inactive = gpio_usbotg_utmi_inactive,
    . transceiver = "utmi" ,
    . wake_up_enable = _wake_up_enable,
} ;
/*将设备注册进系统*/
static inline void dr_register_udc( void )
{
    PDATA- > operating_mode = DR_UDC_MODE; //在OTG功能设备注册的时候这里的模式是“FSL_USB2_DR_OTG ”,时还不知道为什么不开始就直接把模式写成这个而是后该,现在知道了 因为主从和OTG都在用一个资源,所以谁用就的把模式该了。

/*#define PDATA (&dr_utmi_config)PDATA指的就是上面的结构 */
    dr_udc_device. dev. platform_data = PDATA;

    if ( platform_device_register( & dr_udc_device) )
        printk( KERN_ERR "usb: can't register DR gadget/n" ) ;
    else
        printk( KERN_INFO "usb: DR gadget (%s) registered/n" ,
         PDATA- > transceiver) ;
}

上面就完成了设备的注册。

下面看看驱动和设备的链接。

static struct platform_driver udc_driver = {
    . remove = __exit_p( fsl_udc_remove) ,
    /* these suspend and resume are not usb suspend and resume * /
    . suspend = fsl_udc_suspend,  //切换到主设备后的处理过程
    . resume = fsl_udc_resume,  //切换到从设备的处理过程
    . probe = fsl_udc_probe,
    . driver = {
        . name = driver_name, //就是fsl-usb2-udc,用于匹配设备的
        . owner = THIS_MODULE,
    },
}

 


将驱动注册进系统,如果发现了设备就调用Probe函数,因为我们上面注册了设备所以必然调用Probe

static int __init udc_init( void )
{
    printk( KERN_INFO "%s (%s)/n" , driver_desc, DRIVER_VERSION) ;
    return platform_driver_register( & udc_driver) ;//驱动注册进系统
}

发现设备后调用PROBE函数
static int __init fsl_udc_probe( struct platform_device * pdev)
{
    struct resource * res;
    struct fsl_usb2_platform_data * pdata = pdev- > dev. platform_data;
    int ret = - ENODEV;
    unsigned int i;
    u32 dccparams, portsc;

    if ( strcmp ( pdev- > name, driver_name) ) {
        VDBG( "Wrong device/n" ) ;
        return - ENODEV;
    }
/********************************************************/

static struct fsl_udc *udc_controller;

全局变量定义

/*******************************************************/
    udc_controller = kzalloc( sizeof ( struct fsl_udc) , GFP_KERNEL) ;
    if ( udc_controller = = NULL ) {
        ERR( "malloc udc failed/n" ) ;
        return - ENOMEM;
    }
    udc_controller- > pdata = pdata; //私有变量赋值

# ifdef CONFIG_USB_OTG
    /* Memory and interrupt resources will be passed from OTG */
    udc_controller- > transceiver = otg_get_transceiver( ) ;//在OTG功能中已经通过otg_set_transceiver 设置了transceiver结构,这里面就可以GET


    if ( ! udc_controller- > transceiver) {
        printk( KERN_ERR "Can't find OTG driver!/n" ) ;
        ret = - ENODEV;
        goto err1a;
    }

    res = otg_get_resources( ) ; //获得资源
    if ( ! res) {
        DBG( "resource not registered!/n" ) ;
        return - ENODEV;
    }
# else
    if ( ( pdev- > dev. parent) & &
        ( to_platform_device( pdev- > dev. parent) - > resource) ) {
        pdev- > resource =
            to_platform_device( pdev- > dev. parent) - > resource;
        pdev- > num_resources =
            to_platform_device( pdev- > dev. parent) - > num_resources;
    }

    res = platform_get_resource( pdev, IORESOURCE_MEM, 0) ;
    if ( ! res) {
        ret = - ENXIO;
        goto err1a;
    }

    if ( ! request_mem_region( res- > start, resource_size( res) ,
                driver_name) ) {
        ERR( "request mem region for %s failed /n" , pdev- > name) ;
        ret = - EBUSY;
        goto err1a;
    }
# endif
/*将物理地址映射为驱动可以访问的虚拟地址*/
    dr_regs = ioremap( res- > start, resource_size( res) ) ;
    if ( ! dr_regs) {
        ret = - ENOMEM;
        goto err1;
    }
    pdata- > regs = ( void * ) dr_regs; //私有数据接收映射地址
    /*
     * do platform specific init: check the clock, grab/config pins, etc.
     */

/*调用私有数据的初始化函数,关于初始化函数下面分析*/
    if ( pdata- > platform_init & & pdata- > platform_init( pdev) ) {
        ret = - ENODEV;
        goto err2a;
    }

    if ( pdata- > have_sysif_regs)
        usb_sys_regs = ( struct usb_sys_interface * )
                ( ( u32) dr_regs + USB_DR_SYS_OFFSET) ;

    /* Read Device Controller Capability Parameters register */
    dccparams = fsl_readl( & dr_regs- > dccparams) ;
    if ( ! ( dccparams & DCCPARAMS_DC) ) {
        ERR( "This SOC doesn't support device role/n" ) ;
        ret = - ENODEV;
        goto err2;
    }
    /* Get max device endpoints */
    /* DEN is bidirectional ep number, max_ep doubles the number */
    udc_controller- > max_ep = ( dccparams & DCCPARAMS_DEN_MASK) * 2;

# ifdef CONFIG_USB_OTG
    res+ + ;
    udc_controller- > irq = res- > start;
# else
    udc_controller- > irq = platform_get_irq( pdev, 0) ;
# endif
    if ( ! udc_controller- > irq) {
        ret = - ENODEV;
        goto err2;
    }
   /*注册中断,该中断和OTG的中断共享一个*/
    ret = request_irq( udc_controller- > irq, fsl_udc_irq, IRQF_SHARED,
            driver_name, udc_controller) ;
    if ( ret ! = 0) {
        ERR( "cannot request irq %d err %d /n" ,
                udc_controller- > irq, ret) ;
        goto err2;
    }

    /* Initialize the udc structure including QH member and other member */

/*对一些资源进行空间开辟等初始化操作*/
    if ( struct_udc_setup( udc_controller, pdev) ) {
        ERR( "Can't initialize udc data structure/n" ) ;
        ret = - ENOMEM;
        goto err3;
    }

    if ( ! udc_controller- > transceiver) {
        /* initialize usb hw reg except for regs for EP,
         * leave usbintr reg untouched */

        dr_controller_setup( udc_controller) ;
    }

    /* Setup gadget structure */
    udc_controller- > gadget. ops = & fsl_gadget_ops;
    udc_controller- > gadget. is_dualspeed = 1;
    udc_controller- > gadget. ep0 = & udc_controller- > eps[ 0] . ep;
    INIT_LIST_HEAD( & udc_controller- > gadget. ep_list) ;
    udc_controller- > gadget. speed = USB_SPEED_UNKNOWN;
    udc_controller- > gadget. name = driver_name;

    /* Setup gadget.dev and register with kernel */
    dev_set_name( & udc_controller- > gadget. dev, "gadget" ) ;
    udc_controller- > gadget. dev. release = fsl_udc_release;
    udc_controller- > gadget. dev. parent = & pdev- > dev;
    ret = device_register( & udc_controller- > gadget. dev) ;
    if ( ret < 0)
        goto err3;

    if ( udc_controller- > transceiver) {
        udc_controller- > gadget. is_otg = 1;
        /* now didn't support lpm in OTG mode*/
        device_set_wakeup_capable( & pdev- > dev, 0) ;
    }

    /* setup QH and epctrl for ep0 */
    ep0_setup( udc_controller) ;

    /* setup udc->eps[] for ep0 */
    struct_ep_setup( udc_controller, 0, "ep0" , 0) ;
    /* for ep0: the desc defined here;
     * for other eps, gadget layer called ep_enable with defined desc
     */

    udc_controller- > eps[ 0] . desc = & fsl_ep0_desc;
    udc_controller- > eps[ 0] . ep. maxpacket = USB_MAX_CTRL_PAYLOAD;

    /* setup the udc->eps[] for non-control endpoints and link
     * to gadget.ep_list */

    for ( i = 1; i < ( int ) ( udc_controller- > max_ep / 2) ; i+ + ) {
        char name[ 14] ;

        sprintf ( name, "ep%dout" , i) ;
        struct_ep_setup( udc_controller, i * 2, name, 1) ;
        sprintf ( name, "ep%din" , i) ;
        struct_ep_setup( udc_controller, i * 2 + 1, name, 1) ;
    }

    /* use dma_pool for TD management */
    udc_controller- > td_pool = dma_pool_create( "udc_td" , & pdev- > dev,
            sizeof ( struct ep_td_struct) ,
            DTD_ALIGNMENT, UDC_DMA_BOUNDARY) ;
    if ( udc_controller- > td_pool = = NULL ) {
        ret = - ENOMEM;
        goto err4;
    }
    if ( g_iram_size) {
        for ( i = 0; i < IRAM_PPH_NTD; i+ + ) {
            udc_controller- > iram_buffer[ i] =
             USB_IRAM_BASE_ADDR + i * g_iram_size;
            udc_controller- > iram_buffer_v[ i] =
             IO_ADDRESS( udc_controller- > iram_buffer[ i] ) ;
        }
    }
# ifdef POSTPONE_FREE_LAST_DTD
    last_free_td = NULL ;
# endif

    /* disable all INTR */
    fsl_writel( 0, & dr_regs- > usbintr) ;

    dr_wake_up_enable( udc_controller, false ) ;
    udc_controller- > stopped = 1;

    portsc = fsl_readl( & dr_regs- > portsc1) ;
    portsc | = PORTSCX_PHY_LOW_POWER_SPD;
    fsl_writel( portsc, & dr_regs- > portsc1) ;

    if ( udc_controller- > pdata- > usb_clock_for_pm)
        udc_controller- > pdata- > usb_clock_for_pm( false ) ;

    create_proc_file( ) ;
    return 0;

err4:
    device_unregister( & udc_controller- > gadget. dev) ;
err3:
    free_irq( udc_controller- > irq, udc_controller) ;
err2:
    if ( pdata- > platform_uninit)
        pdata- > platform_uninit( pdata) ;
err2a:
    iounmap( ( u8 __iomem * ) dr_regs) ;
err1:
    if ( ! udc_controller- > transceiver)
        release_mem_region( res- > start, resource_size( res) ) ;
err1a:
    kfree( udc_controller) ;
    udc_controller = NULL ;
    return ret;
}


当设备使用主设备时 DEVICE的处理

static int udc_suspend( struct fsl_udc * udc)
{
    u32 mode, usbcmd;

    /* open clock for register access */
    if ( udc_controller- > pdata- > usb_clock_for_pm)
        udc_controller- > pdata- > usb_clock_for_pm( true ) ;

    mode = fsl_readl( & dr_regs- > usbmode) & USB_MODE_CTRL_MODE_MASK;
    usbcmd = fsl_readl( & dr_regs- > usbcmd) ;

    pr_debug( "%s(): mode 0x%x stopped %d/n" , __func__ , mode, udc- > stopped) ;

    /*
     * If the controller is already stopped, then this must be a
     * PM suspend. Remember this fact, so that we will leave the
     * controller stopped at PM resume time.
     */

    if ( udc- > stopped) {
        pr_debug( "gadget already stopped, leaving early/n" ) ;
        udc- > already_stopped = 1;
        goto out;
    }

    if ( mode ! = USB_MODE_CTRL_MODE_DEVICE) {
        pr_debug( "gadget not in device mode, leaving early/n" ) ;
        goto out;
    }

    udc- > stopped = 1;
    /* if the suspend is not for switch to host in otg mode */
    if ( ( ! ( udc- > gadget. is_otg) ) | |
            ( fsl_readl( & dr_regs- > otgsc) & OTGSC_STS_USB_ID) ) {
        dr_wake_up_enable( udc, true ) ;
        dr_phy_low_power_mode( udc, true ) ;
    }

    /* stop the controller */
    usbcmd = fsl_readl( & dr_regs- > usbcmd) & ~ USB_CMD_RUN_STOP;
    fsl_writel( usbcmd, & dr_regs- > usbcmd) ;

    printk( KERN_INFO "USB Gadget suspended/n" ) ;
out:
    if ( udc_controller- > pdata- > usb_clock_for_pm)
        udc_controller- > pdata- > usb_clock_for_pm( false ) ;
    return 0;
}


当切换到从设备时调用

 

static int fsl_udc_resume( struct platform_device * pdev)
{
    pr_debug( "%s(): stopped %d already_stopped %d/n" , __func__ ,
         udc_controller- > stopped, udc_controller- > already_stopped) ;

    /*
     * If the controller was stopped at suspend time, then
     * don't resume it now.
     */

    if ( udc_controller- > already_stopped) {
        udc_controller- > already_stopped = 0;
        pr_debug( "gadget was already stopped, leaving early/n" ) ;
        return 0;
    }

    /* Enable DR irq reg and set controller Run */
    if ( udc_controller- > stopped) {
        dr_wake_up_enable( udc_controller, false ) ;
        dr_phy_low_power_mode( udc_controller, false ) ;
        mdelay( 1) ;

        dr_controller_setup( udc_controller) ;
        dr_controller_run( udc_controller) ;
    }
    udc_controller- > usb_state = USB_STATE_ATTACHED;
    udc_controller- > ep0_dir = 0;

    printk( KERN_INFO "USB Gadget resumed/n" ) ;
    return 0;
}


上面的两个函数就是在上一篇OTG 一中介绍的

gadget_pdrv- > resume ( gadget_pdev ) ;
gadget_pdrv - > suspend ( gadget_pdev , otg_suspend_state ) ;

这两处就是只想的这个函数。而把前面的函数和上面这两个指针链接的地方就是在OTG中的

fsl_otg_start_gadget 函数。

 

从上面我们可以看到以下几点:

1.OTG 功能的从设备使用的资源和私有数据与OTG设备的一致,(主设备也是一致)

2. 从设备主要为OTG功能提供fsl_udc_resume和udc_suspend两个函数。

http://blog.csdn.net/ling1874/article/details/5758893

阅读(722) | 评论(0) | 转发(0) |
给主人留下些什么吧!~~
评论热议
请登录后评论。

登录 注册