首先，我不是做驱动的开发人员。所以只能用自娱自乐来表示我的行为。
我不知道udc和gadget驱动是不是冷门的驱动，资料真是不多。我之前买了一本书，上面说到这些，就教你如何调试已写好的驱动。这样也可以写书，太坑了吧！我随便从网上搜搜都能写的比他好。难道现在的育人机构为了钱都变成了坑人机构。
我以前就希望把自己写过的驱动总结成一个模板，让人能直观的看出linux提供的接口要我们做什么甚至怎么做。虽然做这个比较难，但我还是成功的欺骗了自己，可以做到。
这是自娱自乐第一期，可能废话多了一点，请大家原谅。现在说这个模板。这个是一个未做实际应用的模板，只是编译通过，除了没实践，还缺少DMA和USB的请求类型处理样例。后期我会用它做一个驱动，不断的完善。现在这个应该在理论和实践之间的东西。
常用结构体(别人写的，不是linux-3.2.36，不过差不多)
========================================================USB UDC与gadget驱动=========================================================
/*
*linux内核中usb设备侧驱动程序分为3个层次：UDC驱动、Gadget API和Gadget驱动程序，UDC驱动程序直接访问硬件usb控制器OHCI/EHCI/UHCI，作为usb设备和主机间的底层通信，向上层
*提供与硬件相关操作的回调函数。当前Gadget API是对UDC驱动程序回调函数的简单包装。Gadget驱动程序具体控制系统作为usb设备时的相关功能的实现，使设备表现出“网络连接”、“打印机”
*或“USB Mass Storage”等特性。
*
* 这里的USB设备控制器（UDC）驱动指作为其他USB主机控制器外设的USB硬件设备上底层硬件控制器的驱动，该硬件和驱动负责将USB设备依附于一个USB主机控制器上：比如当某运行linux的手机作为PC
*的U盘时，手机的底层USB控制器行使USB设备控制器的功能，这时候运行在底层的是UDC驱动，而手机成为U盘，在UDC驱动之上仍然需要另一个驱动，对于USB大容量存储器为file storage驱动，这一
*驱动称为gadget驱动（总之是一个运行linux的系统的usb接口作为另一个linux系统的设备）。usb设备驱动调用usb核心提供的API，因此具体驱动与SOC无关。同样，usb gadget驱动调用通用的gadget API
*因此具体gadget驱动也变得与SOC无关。
*UDC驱动和gadget驱动都位于内核的drivers/usb/gadget目录下，S3C2410对应的UDC驱动为s3c2410_udc.c。ether.c、f_serial.c、file_storage.c等文件实现了一些gadget驱动
*/
#include <linux/gadget.h>
-----------------------------------------------------------struct usb_gadget------------------------------------------------------
struct usb_gadget { //描述USB设备控制器
/* readonly to gadget driver */ //针对gadget驱动只读
const struct usb_gadget_ops *ops; //访问硬件函数
struct usb_ep *ep0; //端点0，setup使用
struct list_head ep_list; /* of usb_ep */ //其他端点列表
enum usb_device_speed speed;
unsigned is_dualspeed:1;
unsigned is_otg:1;
unsigned is_a_peripheral:1;
unsigned b_hnp_enable:1; //A-HOST使能了HNP支持
unsigned a_hnp_support:1; //A-HOST支持HNP
unsigned a_alt_hnp_support:1;
const char *name;
struct device dev;
};
------------------------------------------------------struct usb_gadget_ops-------------------------------------------------------
struct usb_gadget_ops { //硬件操作函数
int (*get_frame)(struct usb_gadget *);
int (*wakeup)(struct usb_gadget *);
int (*set_selfpowered) (struct usb_gadget *, int is_selfpowered);
int (*vbus_session) (struct usb_gadget *, int is_active);
int (*vbus_draw) (struct usb_gadget *, unsigned mA);
int (*pullup) (struct usb_gadget *, int is_on);
int (*ioctl)(struct usb_gadget *,
unsigned code, unsigned long param);
};
-----------------------------------------------------struct usb_gadget_driver----------------------------------------------------
struct usb_gadget_driver { //描述gadget驱动
char *function; //描述gadget功能的字符串
enum usb_device_speed speed;
int (*bind)(struct usb_gadget *); //当驱动和gadget绑定时调用
void (*unbind)(struct usb_gadget *);
int (*setup)(struct usb_gadget *, //处理硬件驱动未处理的端点0请求
const struct usb_ctrlrequest *);
void (*disconnect)(struct usb_gadget *);
void (*suspend)(struct usb_gadget *);
void (*resume)(struct usb_gadget *);
/* FIXME support safe rmmod */
struct device_driver driver;
};
-----------------------------------------------------struct usb_request----------------------------------------------------------
struct usb_request { //表示一个传输请求的usb_request（与从机端看到的urb相似）
void *buf;
unsigned length;
dma_addr_t dma;
unsigned no_interrupt:1;
unsigned zero:1;
unsigned short_not_ok:1;
void (*complete)(struct usb_ep *ep,
struct usb_request *req);
void *context;
struct list_head list;
int status;
unsigned actual;
};
----------------------------------------------------------struct usb_ep---------------------------------------------------------
struct usb_ep { //描述一个端点
void *driver_data;
const char *name;
const struct usb_ep_ops *ops;
struct list_head ep_list;
unsigned maxpacket:16;
};
------------------------------------------------------struct usb_ep_ops---------------------------------------------------------
struct usb_ep_ops { //描述端点操作
int (*enable) (struct usb_ep *ep,
const struct usb_endpoint_descriptor *desc);
int (*disable) (struct usb_ep *ep);
struct usb_request *(*alloc_request) (struct usb_ep *ep,
gfp_t gfp_flags);
void (*free_request) (struct usb_ep *ep, struct usb_request *req);
int (*queue) (struct usb_ep *ep, struct usb_request *req,
gfp_t gfp_flags);
int (*dequeue) (struct usb_ep *ep, struct usb_request *req);
int (*set_halt) (struct usb_ep *ep, int value);
int (*set_wedge) (struct usb_ep *ep);
int (*fifo_status) (struct usb_ep *ep);
void (*fifo_flush) (struct usb_ep *ep);
};
--------------------------------------------------------------------------------------------------------------------------------
/*
*UDC和gadget驱动围绕上述数据结构及其成员函数而展开。
*在具体的UDC驱动中，需要封装usb_gadget和每个端点usb_ep，实现端点usb_ep_ops，完成usb_request。另外usb_gadget_register_driver和usb_gadget_unregister_driver这两个API需要由UDC
*驱动提供，gadget驱动会调用它们。
*/
int usb_gadget_register_driver(struct usb_gadget_driver *driver); //注册，在加载模块中调用，该函数中会调用driver->bind()函数，将usb_gadget_driver与具体的gadget绑定
int usb_gadget_unregister_driver(struct usb_gadget_driver *driver); //注销，在卸载模块中调用，告诉UDC驱动不再投入工作，如果UDC正在和USB主机连接，会先调用driver->disconnect()
//函数，而后会调用unbind()函数
//在linux/usb/gadget.h中，封装了一些常用的API：
int usb_ep_enable(struct usb_ep *ep,const struct usb_endpoint_descriptor *desc); //使能端点 ，该函数会调用struct usb_ep_ops->enable()
int usb_ep_disable(struct usb_ep *ep); //禁止端点,该函数会调用struct usb_ep_ops->disable()
struct usb_request *usb_ep_alloc_request(struct usb_ep *ep,gfp_t gfp_flags); //分配一个依附于某端点的 usb_request,该函数会调用struct usb_ep_ops->usb_request()
void usb_ep_free_request(struct usb_ep *ep,struct usb_request *req); //释放一个依附于某端点的 usb_request,该函数会调用struct usb_ep_ops->free_request()
int usb_ep_queue(struct usb_ep *ep, struct usb_request *req, gfp_t gfp_flags);//提交usb_request,该函数告诉UDC完成usb_request（读写buffer），当请求被完成后，该请求对应的completion函数会被调用，
//该函数会调用struct usb_ep_ops->queue()，该函数告诉UDC完成usb_request(读写buffer)，当请求完成后，该请求对应的completion函数会被调用
int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req); //取消usb_request,该函数会调用struct usb_ep_ops->dequeue()
端点FIFO管理：
int usb_ep_fifo_status(struct usb_ep *ep); //该函数会调用truct usb_ep_ops->fifo_status返回目前FIFO中的字节数
void usb_ep_fifo_flush(struct usb_ep *ep); //该函数会调用truct usb_ep_ops->fifo_flush,以flush（冲洗）掉FIFO中的数据
int usb_gadget_frame_number(struct usb_gadget *gadget); //它调用gadget->ops->get_frame(gadget)返回目前的帧号
/*
*S3C2410的UDC驱动在 /driver/usb/gadget/s3c2410_udc.c
*/
/-----------------------------------------------------------------------------------------------------------------------------/
看请求队列的处理
struct xxxxx_request
{
structlist_head queue; /* ep'srequests */
structusb_request req; //对应主机端看到的urb
};
struct xxxxx_ep
{
struct usb_ep ep; //描述一个端点
struct list_head queue;
…
}
/*device/ep0 records init */
INIT_LIST_HEAD(&dev->gadget.ep_list);
INIT_LIST_HEAD(&dev->gadget.ep0->ep_list);
…
/* basic endpoint recordsinit */
for(i = 0; i < XXXXX_ENDPOINTS; i++) {
structxxxxx_ep *ep = &dev->ep[i];
if(i != 0)//除了ep0
list_add_tail(&ep->ep.ep_list, &dev->gadget.ep_list);
…
INIT_LIST_HEAD(&ep->queue);
}
ep0就用gadget里面的，这个在上层的gadget驱动才能看到。Udc只要这样做就可以了
gadget驱动会调用xxxxx_udc_queue把请求插入ep->queue
udc在端点中断时会从对应的queue取出处理，我的模板没体现这点。
下面说udc驱动大概包涵哪些。
1. struct usb_ep_ops
2. struct usb_gadget_ops xxxxx_ops
3. 有一个中断来处理对应的事件，请求一般包涵在次。（目前的模板没有体现）。
事实上现在的模板就是告诉你上面两个要实现什么，及怎么实现。代码中有详细解释。我不多说了。
.H
/***********************************
Copyright(C), 2013 LDP
FileName: xxxxx_udc.h
Author: wwxxxxll
Date:
Description:
History:
Author Date Desc
************************************/
#ifndef __XXXXX_UDC_H__
#define __XXXXX_UDC_H__
/*************配置选项**************/
#define XXXXX_DEBUG_FS //使用debugfs
//struct usb_ep_ops
#define XXXXX_NEWSTYLE //使用udc_start
#define XXXXX_SETWEDHE //实现set_weght方法
#define XXXXX_FIFO_STATUS //支持fifo_status方法
#define XXXXX_FIFO_FLUSH //支持fifo_flush方法
//struct usb_gadget_ops
#define XXXXX_XXXXX_GET_FRAME //支持get_frame
#define XXXXX_WAKEUP //支持wakeup功能
#define XXXXX_SELFPOWERED //selfpowered支持
#define XXXXX_VBUS_SESSION //vbus连接控制支持
#define XXXXXX_PULLUP //usb连接控制支持
#define XXXXX_HAVE_CLK //有专用的CLK
#ifdef XXXXX_HAVE_CLK
#define CLK_DELAY_TIME 10 //ms
#endif
#define XXXXX_USE_IRQ
//端口信息
#define XXXXX_ENDPOINTS 2 //端口数
#define EP0_FIFO_SIZE 8
#define EP1_FIFO_SIZE 64
#define EP1_ADDRESS 1
#define EP1_ATTR USB_ENDPOINT_XFER_BULK
#define XXXXX_EP_FILO_SIZE 128
/***********************************/
/*************寄存器定义************/
/***********************************/
struct xxxxx_ep
{
struct usb_ep ep; //描述一个端点
struct list_head queue;
struct xxxxx_udc *dev;
const struct usb_endpoint_descriptor *desc;
unsigned char fifosize;
unsigned char bEndpointAddress;
unsigned char bmAttributes;
u16 fifo_size;
u8 num;
unsigned stopped :1;//维护一个端口停止标志
#ifdef XXXXX_SETWEDHE
unsigned wedged :1;
#endif
};
#define to_xxxxx_ep(ep_p) container_of(ep_p, struct xxxxx_ep, ep)
struct xxxxx_request
{
struct list_head queue; /* ep's requests */
struct usb_request req; //对应主机端看到的urb
};
#define to_xxxxx_req(req_p) container_of(req_p, struct xxxxx_request, req)
//根据实际要求定义，这个不能当做模板，主要是便于软件管理
//一般有下面几个，有的驱动不用这些定义去管理
enum ep0state {
EP0_IDLE,
EP0_IN,
EP0_OUT,
EP0_STALL,
};
struct xxxxx_udc
{
spinlock_t lock;
void __iomem *virl_addr;
u32 phy_addr;
u32 reg_size;
struct usb_gadget gadget;
struct usb_gadget_driver *driver;
enum ep0state ep0state;
struct xxxxx_ep ep[XXXXX_ENDPOINTS];
struct xxxxx_request fifo_req;
#ifdef XXXXX_DEBUG_FS
struct dentry *debug_info;
#endif
#ifdef XXXXX_HAVE_CLK
struct clk *xxxxx_clk;
#endif
#ifdef XXXXX_USE_IRQ
unsigned int irq_num;
#endif
u16 devstatus;
};
#define to_xxxxx_udc(gadget_p) container_of(gadget_p, struct xxxxx_udc, gadget)
#endif//__XXXXX_UDC_H__
.c
/***********************************
Copyright(C), 2013 LDP
FileName: xxxxx_udc.c
Author: wwxxxxll
Date:
Description: linux-3.2-36
History:
Author Date Desc
************************************/
#include <linux/module.h>//MODULE_*
#include <linux/init.h>//printk
#include <linux/slab.h>//kzalloc() kfree()
#include <linux/usb/gadget.h>//struct usb_gadget等
#include <linux/clk.h>//struct clk
#include <linux/platform_device.h>//platform
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <asm/irq.h>
#include <asm/io.h>//ioremap
#include "xxxxx_udc.h"
#ifdef XXXXX_DEBUG_FS
#include <linux/debugfs.h>
#include <linux/seq_file.h>//seq_printf seq_read
#endif
#define DRIVER_DESC "XXXXX USB Device Controller Gadget"
#define DRIVER_VERSION "2013"
#define DRIVER_AUTHOR "wwxxxxll"
static const char gadget_name[] = "xxxxx_udc";
static const char driver_desc[] = DRIVER_DESC;
//根据实际情况修改
static const char ep0name[] = "ep0";
static const char * const ep_name[] = {
ep0name,
"ep1",
};
#ifdef XXXXX_DEBUG_FS
static struct dentry *xxxxx_udc_debugfs_root;
static int xxxxx_udc_debugfs_seq_show(struct seq_file *m, void *p)
{
seq_printf(m, "My name is %s
", gadget_name);
return 0;
}
static int xxxxx_udc_debugfs_fops_open(struct inode *inode,
struct file *file)
{
return single_open(file, xxxxx_udc_debugfs_seq_show, NULL);
}
static const struct file_operations xxxxx_udc_debugfs_fops =
{
.open = xxxxx_udc_debugfs_fops_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
.owner = THIS_MODULE,
};
#endif
/***********************hardware_handler************************/
static void xxxxx_usb_reset(struct xxxxx_udc *dev)
{
//硬件操作
}
//udc的这个中断，真是包罗万象，各硬件差别比较大
//简单一点说，就是清楚中断标致位，再根据中断标志位对应处理
//实际要复杂的多，如果是ep0，还会从fifo中取得usb_ctrlrequest
//进行对应的处理，我们在实现具体的实现时再说吧
static irqreturn_t xxxxx_udc_irq(int dummy, void *_dev)
{
return IRQ_HANDLED;
}
/***************************************************************/
/***********************queue***********************************/
//对于usb请求，一般都要维护一个list去管理请求
//端点list初始化，存入gadget里
static void xxxxx_usb_reinit(struct xxxxx_udc *dev)
{
u32 i;
/* device/ep0 records init */
INIT_LIST_HEAD (&dev->gadget.ep_list);
dev->gadget.ep0 = &dev->ep[0].ep;//ep0单独存放
dev->gadget.speed = USB_SPEED_UNKNOWN;
dev->ep0state = EP0_IDLE;
INIT_LIST_HEAD (&dev->gadget.ep0->ep_list);
for (i = 0; i < XXXXX_ENDPOINTS; i++) {
struct xxxxx_ep *ep = &dev->ep[i];
if (i != 0)
list_add_tail (&ep->ep.ep_list, &dev->gadget.ep_list);
ep->dev = dev;
ep->desc = NULL;
ep->stopped = 0;
INIT_LIST_HEAD (&ep->queue);
}
}
static void xxxxx_udc_done(struct xxxxx_ep *ep, struct xxxxx_request *req, int status)
{
struct xxxxx_udc *dev;
unsigned stopped = ep->stopped;
list_del_init(&req->queue);
if (likely (req->req.status == -EINPROGRESS))//正在进行中
req->req.status = status;
else
status = req->req.status;
dev = ep->dev;
/* don't modify queue heads during completion callback */
ep->stopped = 1;
//先解锁再加锁，加锁是在dequeue_all调用前做的
spin_unlock(&dev->lock);
req->req.complete(&ep->ep, &req->req);
spin_lock(&dev->lock);
ep->stopped = stopped;
}
static void xxxxx_dequeue_all(struct xxxxx_ep *ep, int status)
{
struct xxxxx_request *req;
if (&ep->queue == NULL)
return;
while (!list_empty(&ep->queue)) //list_del_init会删除链表中的元素
{
req = list_entry(ep->queue.next, struct xxxxx_request, queue);
xxxxx_udc_done(ep, req, status);
}
}
/***************************************************************/
//may not be the endpoint named "ep0".这是gadget.h的源话
/**************************ep_ops*******************************/
//描述端点操作
//当设备配置或接口设置改变时，驱动会enable或disable端口
static int xxxxx_udc_ep_enable(struct usb_ep *_ep, const struct usb_endpoint_descriptor *desc)
{
struct xxxxx_udc *dev;
struct xxxxx_ep *ep;
u32 max;
unsigned long flags;
ep = to_xxxxx_ep(_ep);
if (!_ep || !desc || ep->desc
|| (desc->bDescriptorType != USB_DT_ENDPOINT)
|| (_ep->name == ep0name))
return -EINVAL;
dev = ep->dev;
if (!dev->driver || dev->gadget.speed == USB_SPEED_UNKNOWN)
return -ESHUTDOWN;
max = usb_endpoint_maxp(desc) & 0x1fff;
spin_lock_irqsave(&dev->lock, flags);
_ep->maxpacket = max & 0x7fff;
ep->desc = desc;
ep->stopped = 0;
#ifdef XXXXX_SETWEDHE
ep->wedged = 0;
#endif
ep->bEndpointAddress = desc->bEndpointAddress;
//寄存器操作
spin_unlock_irqrestore(&dev->lock, flags);
return 0;
}
static int xxxxx_udc_ep_disable(struct usb_ep *_ep)
{
struct xxxxx_ep *ep = to_xxxxx_ep(_ep);
unsigned long flags;
if (!_ep || !ep->desc) {
return -EINVAL;
}
local_irq_save(flags);
ep->desc = NULL;
ep->stopped = 1;
//清除请求list和关闭ep
xxxxx_dequeue_all(ep, -ESHUTDOWN);//关机后将无法传输端点
local_irq_restore(flags);
return 0;
}
//动态分配请求
static struct usb_request *xxxxx_udc_alloc_request(struct usb_ep *_ep, gfp_t gfp_flags)
{
struct xxxxx_request *req;
if (!_ep)
return NULL;
req = kzalloc (sizeof(struct xxxxx_request), gfp_flags);
if (!req)
return NULL;
INIT_LIST_HEAD (&req->queue);
return &req->req;
}
//释放请求
static void xxxxx_udc_free_request(struct usb_ep *_ep, struct usb_request *_req)
{
//struct xxxxx_ep *ep = to_xxxxx_ep(_ep);
struct xxxxx_request *req = to_xxxxx_req(_req);
if (!_ep || !_req)
return;
WARN_ON (!list_empty (&req->queue));
kfree(req);
}
//下面的queue是插入一个请求
//dequeue删除一个请求
static int xxxxx_udc_queue(struct usb_ep *_ep, struct usb_request *_req, gfp_t gfp_flags)
{
struct xxxxx_udc *dev;
unsigned long flags;
struct xxxxx_request *req = to_xxxxx_req(_req);
struct xxxxx_ep *ep = to_xxxxx_ep(_ep);
if (unlikely (!_ep || (!ep->desc && ep->num != 0))) //这个逻辑下面会看到很多（_ep为空或[ep->desc为空且不是0端点]）
{
return -EINVAL;
}
dev = ep->dev;
if (unlikely (!dev->driver || dev->gadget.speed == USB_SPEED_UNKNOWN))
{
return -ESHUTDOWN;
}
if (unlikely(!_req || !_req->complete
|| !_req->buf || !list_empty(&req->queue))) //_req或_req->buf为空、complete执行错误、req->queue不为空
{
return -EINVAL;
}
local_irq_save (flags);
//硬件操作
if (likely(req != 0))
list_add_tail(&req->queue, &ep->queue);//请求入list
local_irq_restore(flags);
return 0;
}
static int xxxxx_udc_dequeue(struct usb_ep *_ep, struct usb_request *_req)
{
struct xxxxx_ep *ep = to_xxxxx_ep(_ep);
struct xxxxx_udc *dev;
int retval = -EINVAL;
unsigned long flags;
struct xxxxx_request *req = NULL;
if (!_ep || !_req)
return retval;
dev = ep->dev;
if (!dev->driver)
return -ESHUTDOWN;
local_irq_save (flags);
list_for_each_entry (req, &ep->queue, queue)
{
if (&req->req == _req)
{
list_del_init (&req->queue);
_req->status = -ECONNRESET;//Connection reset by peer
retval = 0;
break;
}
}
if (retval == 0)
{
xxxxx_udc_done(ep, req, -ECONNRESET);
}
local_irq_restore (flags);
return retval;
}
#ifdef XXXXX_FIFO_STATUS
//fifo状态，返回fifo中的字节数。
//在上层的调用usb_ep_fifo_statu()如果不用fifo或不支持这个操作返回错误-EOPNOTSUPP
//net2272就有寄存器EP_AVAIL记录fifo中的字节数。
//s3c2440硬件不支持，没实现，上层调用会得到-EOPNOTSUPP
static int xxxxx_udc_fifo_status(struct usb_ep *_ep)
{
struct xxxxx_ep *ep;
u16 retval = 0;
ep = to_xxxxx_ep(_ep);
if (!_ep || (!ep->desc && ep->num != 0))
return -ENODEV;
if (!ep->dev->driver || ep->dev->gadget.speed == USB_SPEED_UNKNOWN)
return -ESHUTDOWN;
//retval = 读寄存器
return retval;
}
#endif
#ifdef XXXXX_FIFO_FLUSH
//冲掉fifo的不明确数据，这个决不用除非端点不能用于任何协议传输，这是上层调用的事
static void xxxxx_udc_fifo_flush(struct usb_ep *_ep)
{
struct xxxxx_ep *ep;
ep = to_xxxxx_ep(_ep);
if (!_ep || (!ep->desc && ep->num != 0))
return;
if (!ep->dev->driver || ep->dev->gadget.speed == USB_SPEED_UNKNOWN)
return;
//寄存器操作
}
#endif
/*
上层调用usb_ep_set_wedge
停止一个端点并忽略CLEAR_FEATURE请求。如果Gadget驱动清除停止状态，它将自动Unwedge端点
一般用一个位wedge表示
如果没有实现set_wedge方法。就用set_halt(ep, 1);代替
我们看个例子（在file_storage.c中）
Bulk-only
当出现无效的CBW时
Bulk-only Spec说我们必须停止IN 端点。还说必须保持这个状态知道下一次的reset，但是没有办法
告诉控制器忽略CLEAR_FEATURE请求。所以我们用一个位来记录，搞定！
下面是参考net2272的代码，
value=1:set_halt
= 0:clear_halt
*/
static int xxxxx_set_halt_and_wedge(struct usb_ep *_ep, int value, int wedged)
{
struct xxxxx_ep *ep;
unsigned long flags;
int ret = 0;
ep = container_of(_ep, struct xxxxx_ep, ep);
if (!_ep || (!ep->desc && ep->num != 0))
return -EINVAL;
if (!ep->dev->driver || ep->dev->gadget.speed == USB_SPEED_UNKNOWN)
return -ESHUTDOWN;
if (ep->desc /* not ep0 */ && usb_endpoint_xfer_isoc(ep->desc))//判断是不是同步端点，见下面
return -EINVAL;
spin_lock_irqsave(&ep->dev->lock, flags);
if (!list_empty(&ep->queue))
ret = -EAGAIN;
#ifdef XXXXX_FIFO_STATUS
else if ((ep->bEndpointAddress & USB_DIR_IN) && value && xxxxx_udc_fifo_status(_ep) != 0)//fifo_status是上面实现的
ret = -EAGAIN;
#endif
else {
/* set/clear */
if (value) {
if (ep->num == 0)
{
ep->dev->ep0state = EP0_STALL;
ep->stopped = 1;
//net2272的端点0在setup时自动复位，没有什么操作。s3c2440就不是了
//ep->dev->protocol_stall = 1;
//ep0 set_halt
}
else
//epx(x != 0) set_halt
if (wedged)//维护wedged
ep->wedged = 1;
} else {
//ep clear_halt
ep->wedged = 0;
}
}
spin_unlock_irqrestore(&ep->dev->lock, flags);
return ret;
}
//_ep 不能是同步端点，同步端点不支持错误重发机制。在上面判断
static int xxxxx_udc_set_halt(struct usb_ep *_ep, int value)
{
return xxxxx_set_halt_and_wedge(_ep, value, 0);
}
#ifdef XXXXX_SETWEDHE
static int xxxxx_udc_set_wedge(struct usb_ep *_ep)
{
if (!_ep || _ep->name == ep0name)//一般都是端点0请求复位
return -EINVAL;
return xxxxx_set_halt_and_wedge(_ep, 1, 1);
}
#endif
static const struct usb_ep_ops xxxxx_ep_ops =
{
.enable = xxxxx_udc_ep_enable,
.disable = xxxxx_udc_ep_disable,
.alloc_request = xxxxx_udc_alloc_request,
.free_request = xxxxx_udc_free_request,
.queue = xxxxx_udc_queue,
.dequeue = xxxxx_udc_dequeue,
.set_halt = xxxxx_udc_set_halt,
#ifdef XXXXX_SETWEDHE
.set_wedge = xxxxx_udc_set_wedge,
#endif
#ifdef XXXXX_FIFO_STATUS
.fifo_status = xxxxx_udc_fifo_status,
#endif
#ifdef XXXXX_FIFO_FLUSH
.fifo_flush = xxxxx_udc_fifo_flush,
#endif
};
/***************************************************************/
//USB 设备的常用操作包括：设备连接、设备移除、设备配置、地址分配、数据传输、
//设备挂起、设备唤醒等。
/**************************usb_gadget_ops***********************/
//硬件操作函数
//获取帧号，当主机发送USB 数据包时，每个帧的开始（SOF）包包含一个帧号。
//这个帧号一般自动加载到对应寄存器，此函数主要就是读这些寄存器
//如果设备不支持返回负
static int xxxxx_udc_get_frame(struct usb_gadget *usb_gdt_p)
{
#ifdef XXXXX_GET_FRAME
struct xxxxx_udc *dev = to_xxxxx_udc(usb_gdt_p);
int retval = 0;
unsigned long flags;
spin_lock_irqsave(&dev->lock, flags);
//retval = 读寄存器
spin_unlock_irqrestore(&dev->lock, flags);
return retval;
#else
return -EOPNOTSUPP;
#endif
}
#ifdef XXXXX_WAKEUP
//唤醒，举个例子net2272。它的寄存器usbctl0的第五位控制唤醒功能使能
//寄存器usbctl1的第三位通过写1去resume，s3c2440在PWR_REG也有类似
static int xxxxx_udc_wakeup(struct usb_gadget *usb_gdt_p)
{
struct xxxxx_udc *dev = to_xxxxx_udc(usb_gdt_p);
unsigned long flags;
spin_lock_irqsave(&dev->lock, flags);
//寄存器操作
spin_unlock_irqrestore(&dev->lock, flags);
return 0;
}
#endif
#ifdef XXXXX_SELFPOWERED
//设置自供电标志(selfpowered feature)，一般就用一个变量位或一个位记录一下。USB_RECIP_DEVICE时返回状态
static int xxxxx_udc_set_selfpowered (struct usb_gadget *usb_gdt_p, int is_selfpowered)
{
struct xxxxx_udc *dev = to_xxxxx_udc(usb_gdt_p);
if (is_selfpowered)
dev->devstatus |= (1 << USB_DEVICE_SELF_POWERED);
else
dev->devstatus &= ~(1 << USB_DEVICE_SELF_POWERED);
return 0;
}
#endif
#ifdef XXXXX_VBUS_SESSION
//vbus在硬件上就是usb的电源脚，这个函数就是来控制它。一般通过一个gpio拉高拉底
//这个vbus会话，实际的我看了s3c2410和at91的处理，就是让usb的D+线与一个gpio口连接
//通过置1置0来控制usb
static int xxxxx_udc_vbus_session (struct usb_gadget *usb_gdt_p, int is_active)
{
struct xxxxx_udc *dev = to_xxxxx_udc(usb_gdt_p);
unsigned long flags;
spin_lock_irqsave(&dev->lock, flags);
//寄存器操作
spin_unlock_irqrestore(&dev->lock, flags);
return 0;
}
#endif
#ifdef XXXXX_VBBUS_DRAW
//强制vbus电源控制器行为，在SET_CONFIGRATION时，设置vbus的电流量
//vbus应该是表示总线电压，在硬件上是一个脚
//主要是对usb电流的设置，看一下gta02平台，这个函数会操作pcf50633(一种移动设备的电源管理芯片）
static int xxxxx_udc_vbus_draw (struct usb_gadget *usb_gdt_p, unsigned mA)
{
return 0;
}
#endif
#ifdef XXXXXX_PULLUP
//这个和上面的vbus_session区别是
//vbus_session是控制vbus的连接
//pullup是控制usb模块的连接
//在udc-core.c中newstyle的驱动probe函数时才调用它，所以你要实现udc_start和udc_stop，
//当然除了注册，也可以通过sysfs调用它。和newstyle无关。
//composite.c也有一些调用
//这个就是根据is_on来connect或disconnect usb
//net2272就是由USBCTL0的第三位控制的，s3c2440还是通过gpio和vbus_session没
//区别
static int xxxxx_udc_pullup (struct usb_gadget *usb_gdt_p, int is_on)
{
struct xxxxx_udc *dev = to_xxxxx_udc(usb_gdt_p);
unsigned long flags;
spin_lock_irqsave(&dev->lock, flags);
if (is_on)
{
//enable
}
else
{
//disable
}
spin_unlock_irqrestore(&dev->lock, flags);
return 0;
}
#endif
//不好意思，我看了linux-3.2.36的/gadget的目录没发现有实现这个的硬件
static int xxxxx_udc_ioctl(struct usb_gadget *usb_gdt_p, unsigned code, unsigned long param)
{
return 0;
}
//这个也没看驱动实现它，从名字就是获取配置参数，就简单看看struct usb_dcd_config_params
/*
struct usb_dcd_config_params {
__u8 bU1devExitLat; // U1 Device exit Latency u1设备等待时间
#define USB_DEFAULT_U1_DEV_EXIT_LAT 0x01 // Less then 1 microsec 至少1微秒
__le16 bU2DevExitLat; // U2 Device exit Latency
#define USB_DEFAULT_U2_DEV_EXIT_LAT 0x1F4 // Less then 500 microsec
};
对应struct usb_ss_cap_descriptor 中的成员
每一个I/O请求包延迟时间限制
*/
static void xxxxx_udc_get_config_params(struct usb_dcd_config_params *usb_dc_cfg_pm)
{
}
//在udc-core.c中start和udc_start的解释一样，在bind()之前调用，只要实现一个就行了
//我知道start主要有bind回调
//udc_start主要是设备执行了non-control请求后，要重新连接，net2272和r8a66597实现的就是它
#ifdef XXXXX_NEWSTYLE
static int xxxxx_udc_start(struct usb_gadget *usb_gdt_p, struct usb_gadget_driver *driver);
static int xxxxx_udc_stop(struct usb_gadget *usb_gdt_p, struct usb_gadget_driver *driver);
#else
//s3c2410 xxxxx 实现它
static int xxxxx_start(struct usb_gadget_driver *driver, int (*bind)(struct usb_gadget *));
static int xxxxx_stop(struct usb_gadget_driver *driver);
#endif
static const struct usb_gadget_ops xxxxx_ops =
{
.get_frame = xxxxx_udc_get_frame,
#ifdef XXXXX_WAKEUP
.wakeup = xxxxx_udc_wakeup,
#endif
#ifdef XXXXX_SELFPOWERED
.set_selfpowered = xxxxx_udc_set_selfpowered,
#endif
#ifdef XXXXX_VBUS_SESSION
.vbus_session = xxxxx_udc_vbus_session,
#endif
#ifdef XXXXX_VBBUS_DRAW
.vbus_draw = xxxxx_udc_vbus_draw,
#endif
#ifdef XXXXXX_PULLUP
.pullup = xxxxx_udc_pullup,
#endif
.ioctl = xxxxx_udc_ioctl,
.get_config_params = xxxxx_udc_get_config_params,
#ifdef XXXXX_NEWSTYLE
.udc_start = xxxxx_udc_start,
.udc_stop = xxxxx_udc_stop,
#else
.start = xxxxx_start,
.stop = xxxxx_stop,
#endif
};
/***************************************************************/
/***************************************************************/
static struct xxxxx_udc udc_info = {
.gadget = {
.ops = &xxxxx_ops,
.ep0 = &udc_info.ep[0].ep,
.name = gadget_name,
.dev = {
.init_name = "gadget",
},
/*
根据自己的硬件选择
unsigned is_dualspeed:1;
unsigned is_otg:1;
unsigned is_a_peripheral:1;
unsigned b_hnp_enable:1; //hnp:主机协商协议 otg特有的
unsigned a_hnp_support:1;
unsigned a_alt_hnp_support:1;
*/
},
/* control endpoint */
.ep[0] = {
.num = 0,
.ep =
{
.name = "ep0",
.ops = &xxxxx_ep_ops,
.maxpacket = EP0_FIFO_SIZE,
},
.dev = &udc_info,
},
/* first group of endpoints */
.ep[1] = {
.num = 1,
.ep =
{
.name = "ep1",
.ops = &xxxxx_ep_ops,
.maxpacket = EP1_FIFO_SIZE,
},
.dev = &udc_info,
.fifo_size = EP1_FIFO_SIZE,
.bEndpointAddress = EP1_ADDRESS,
.bmAttributes = EP1_ATTR,
},
};
static void stop_activity(struct xxxxx_udc *dev, struct usb_gadget_driver *driver)
{
unsigned i;
if (dev->gadget.speed == USB_SPEED_UNKNOWN)
driver = NULL;
/* disconnect gadget driver after quiesceing hw and the driver */
xxxxx_usb_reset(dev);//复位或disable
for (i = 0; i < XXXXX_ENDPOINTS; i++)
{
xxxxx_dequeue_all(&dev->ep[i], -ECONNABORTED);
}
#ifndef XXXXX_NEWSTYLE
/*
if (udc_is_newstyle(udc)) {
udc->driver->disconnect(udc->gadget);
udc->driver->unbind(udc->gadget);
usb_gadget_udc_stop(udc->gadget, udc->driver);
usb_gadget_disconnect(udc->gadget);//对应pull_up
} else {
usb_gadget_stop(udc->gadget, udc->driver);//所以非newstyle要disconnect
}
*/
if (driver)
{
spin_unlock(&dev->lock);
driver->disconnect(&dev->gadget);
spin_lock(&dev->lock);
}
#endif
if (dev->driver)
{
xxxxx_usb_reinit(dev);//重初始化
}
}
#ifdef XXXXX_NEWSTYLE
/*
udc 的probe函数
if (udc_is_newstyle(udc)) {//是否实现udc_start and udc_stop
ret = bind(udc->gadget);
if (ret)
goto err1;
ret = usb_gadget_udc_start(udc->gadget, driver);//已绑定,bind是gadget实现的
if (ret) {
driver->unbind(udc->gadget);
goto err1;
}
usb_gadget_connect(udc->gadget);//上面的pullup
} else {
ret = usb_gadget_start(udc->gadget, driver, bind);
if (ret)
goto err1;
}
*/
//net2272和r8a66597实现的就是它
//下面参考net2272
static int xxxxx_udc_start(struct usb_gadget *usb_gdt_p, struct usb_gadget_driver *driver)
{
struct xxxxx_udc *dev;
if (!driver || !driver->unbind || !driver->setup ||
driver->speed != USB_SPEED_HIGH)
return -EINVAL;
dev = container_of(usb_gdt_p, struct xxxxx_udc, gadget);
/* hook up the driver ... */
driver->driver.bus = NULL;
dev->driver = driver;
dev->gadget.dev.driver = &driver->driver;
//使能udc，硬件操作
return 0;
}
static int xxxxx_udc_stop(struct usb_gadget *usb_gdt_p, struct usb_gadget_driver *driver)
{
struct xxxxx_udc *dev;
unsigned long flags;
dev = container_of(usb_gdt_p, struct xxxxx_udc, gadget);
spin_lock_irqsave(&dev->lock, flags);
stop_activity(dev, driver);
spin_unlock_irqrestore(&dev->lock, flags);
dev->gadget.dev.driver = NULL;
dev->driver = NULL;
return 0;
}
#else
//s3c2410 goku实现它，参考goku
static int xxxxx_start(struct usb_gadget_driver *driver, int (*bind)(struct usb_gadget *usb_gdt_p))
{
struct xxxxx_udc *dev = &udc_info;
int retval = 0;
if (!driver
|| driver->speed < USB_SPEED_FULL
|| !bind
|| !driver->disconnect
|| !driver->setup)
return -EINVAL;
if (!dev)
return -ENODEV;
if (dev->driver)
return -EBUSY;
/* hook up the driver */
driver->driver.bus = NULL;
dev->driver = driver;
dev->gadget.dev.driver = &driver->driver;
if ((retval = device_add(&dev->gadget.dev)) != 0)
{
goto register_error;
}
retval = bind(&dev->gadget);
if (retval)
{
device_del(&dev->gadget.dev);
goto register_error;
}
//使能udc，硬件操作
register_error:
dev->driver = NULL;
dev->gadget.dev.driver = NULL;
return retval;
}
static int xxxxx_stop(struct usb_gadget_driver *driver)
{
struct xxxxx_udc *dev = &udc_info;
unsigned long flags;
if (!dev)
return -ENODEV;
if (!driver || driver != dev->driver || !driver->unbind)
return -EINVAL;
spin_lock_irqsave(&dev->lock, flags);
dev->driver = NULL;
stop_activity(dev, driver);
spin_unlock_irqrestore(&dev->lock, flags);
driver->unbind(&dev->gadget);
dev->gadget.dev.driver = NULL;
dev->driver = NULL;
device_del(&dev->gadget.dev);
return 0;
}
#endif
/***************************************************************/
static int xxxxx_udc_probe(struct platform_device *pdev)
{
struct xxxxx_udc *udc = &udc_info;
struct device *dev = &pdev->dev;
int retval;
struct resource *res;
#ifdef XXXXX_USE_IRQ
struct resource *resirq;
#endif
resource_size_t res_size;
dev_dbg(dev, "%s()
", __func__);
#ifdef XXXXX_HAVE_CLK
udc->xxxxx_clk = clk_get(NULL, "xxxxx");
if (IS_ERR(udc->xxxxx_clk))
{
dev_err(dev, "failed to get usb bus clock source
");
return PTR_ERR(udc->xxxxx_clk);
}
clk_enable(udc->xxxxx_clk);
#if (CLK_DELAY_TIME != 0)
mdelay(CLK_DELAY_TIME);
#endif
dev_dbg(dev, "got and enabled clocks
");
#endif //XXXXX_HAVE_CLK
if (strncmp(pdev->name, "xxxxx", 7) == 0) {
dev_info(dev, "xxxxx: increasing FIFO to %d bytes
", XXXXX_EP_FILO_SIZE);
udc_info.ep[1].fifo_size = XXXXX_EP_FILO_SIZE;
}
spin_lock_init (&udc->lock);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
{
dev_err(&pdev->dev, "can't get device resources
");
retval = -ENODEV;
goto err_clk;
}
/*
pdata = pdev->dev.platform_data;
if (!pdata) {
dev_err(&pdev->dev, "driver needs platform data
");
return -ENODEV;
}
*/
res_size = resource_size(res);
if (!request_mem_region(res->start, res_size, res->name))
{
dev_err(&pdev->dev, "can't allocate %d bytes at %d address
",
res_size, res->start);
retval = -ENOMEM;
goto err_clk;
}
udc->virl_addr = ioremap(res->start, res_size);
if (!udc->virl_addr)
{
retval = -ENOMEM;
goto err_mem;
}
udc->phy_addr = res->start;
udc->reg_size = res_size;
device_initialize(&udc->gadget.dev);
udc->gadget.dev.parent = &pdev->dev;
udc->gadget.dev.dma_mask = pdev->dev.dma_mask;
platform_set_drvdata(pdev, udc);
//少不了硬件初始化
xxxxx_usb_reset(udc);
xxxxx_usb_reinit(udc);
#ifdef XXXXX_USE_IRQ
resirq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
if (!resirq)
{
dev_err(&pdev->dev, "can't get device irq resources
");
retval = -ENODEV;
goto err_map;
}
udc->irq_num = resirq->start;
/* irq setup after old hardware state is cleaned up */
retval = request_irq(udc->irq_num, xxxxx_udc_irq, 0, gadget_name, udc);
if (retval != 0)
{
dev_err(dev, "cannot get irq %i, err %d
", udc->irq_num, retval);
retval = -EBUSY;
goto err_map;
}
dev_dbg(dev, "got irq %i
", udc->irq_num);
#endif
retval = usb_add_gadget_udc(&pdev->dev, &udc->gadget);
if (retval)
goto err_int;
#ifdef XXXXX_DEBUG_FS
if (xxxxx_udc_debugfs_root)
{
udc->debug_info = debugfs_create_file("registers", S_IRUGO, xxxxx_udc_debugfs_root,
udc, &xxxxx_udc_debugfs_fops);
if (!udc->debug_info)
dev_warn(dev, "debugfs file creation failed
");
}
#endif
dev_dbg(dev, "probe ok
");
return 0;
err_int:
#ifdef XXXXX_USE_IRQ
free_irq(udc->irq_num, udc);
#endif
err_map:
iounmap(udc->virl_addr);
err_mem:
release_mem_region(res->start, res_size);
err_clk:
#ifdef XXXXX_HAVE_CLK
clk_put(udc->xxxxx_clk);
clk_disable(udc->xxxxx_clk);
#endif
return retval;
}
static int xxxxx_udc_remove(struct platform_device *pdev)
{
struct xxxxx_udc *udc = platform_get_drvdata(pdev);
dev_dbg(&pdev->dev, "%s()
", __func__);
usb_del_gadget_udc(&udc->gadget);
if (udc->driver)
return -EBUSY;
#ifdef XXXXX_DEBUG_FS
debugfs_remove(udc->debug_info);
#endif
#ifdef XXXXX_USE_IRQ
free_irq(udc->irq_num, udc);
#endif
iounmap(udc->virl_addr);
release_mem_region(udc->phy_addr, udc->reg_size);
platform_set_drvdata(pdev, NULL);
#ifdef XXXXX_HAVE_CLK
if (!IS_ERR(udc->xxxxx_clk) && udc->xxxxx_clk != NULL) {
clk_disable(udc->xxxxx_clk);
clk_put(udc->xxxxx_clk);
udc->xxxxx_clk = NULL;
}
#endif
dev_dbg(&pdev->dev, "%s: remove ok
", __func__);
return 0;
}
#ifdef CONFIG_PM
static int xxxxx_udc_suspend(struct platform_device *pdev, pm_message_t message)
{
return 0;
}
static int xxxxx_udc_resume(struct platform_device *pdev)
{
return 0;
}
#else
#define xxxxx_udc_suspend NULL
#define xxxxx_udc_resume NULL
#endif
/***************************************************************/
static const struct platform_device_id xxxxx_udc_ids[] = {
{ "xxxxx-usbgadget", },
{ }
};
MODULE_DEVICE_TABLE(platform, xxxxx_udc_ids);
//有些设备可能用struct pci_driver，我就不考虑这么多了。
static struct platform_driver udc_driver_xxxxx = {
.driver = {
.name = "xxxxx-usbgadget",
.owner = THIS_MODULE,
},
.probe = xxxxx_udc_probe,
.remove = __exit_p(xxxxx_udc_remove),
.suspend = xxxxx_udc_suspend,
.resume = xxxxx_udc_resume,
.id_table = xxxxx_udc_ids,
};
static int __init udc_init(void)
{
int retval;
xxxxx_udc_debugfs_root = debugfs_create_dir(gadget_name, NULL);
if (IS_ERR(xxxxx_udc_debugfs_root)) {
printk(KERN_ERR "%s: debugfs dir creation failed %ld
",
gadget_name, PTR_ERR(xxxxx_udc_debugfs_root));
xxxxx_udc_debugfs_root = NULL;
}
retval = platform_driver_register(&udc_driver_xxxxx);
if (retval)
goto err;
return 0;
err:
debugfs_remove(xxxxx_udc_debugfs_root);
return retval;
}
static void __exit udc_exit(void)
{
platform_driver_unregister(&udc_driver_xxxxx);
debugfs_remove(xxxxx_udc_debugfs_root);
}
module_init(udc_init);
module_exit(udc_exit);
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL");
下期预告：
基于模板实现一个实际的udc驱动。