OTG驱动分析（二）

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。