USB子系统gadget analyse
struct usb_gadget_driver {
char *function;
enum usb_device_speed speed;
void (*unbind)(struct usb_gadget *);
int (*setup)(struct usb_gadget *,
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 s3c2410_udc {spinlock_t lock;struct s3c2410_ep ep[S3C2410_ENDPOINTS];int address;struct usb_gadget gadget;struct usb_gadget_driver *driver;struct s3c2410_request fifo_req;u8 fifo_buf[EP_FIFO_SIZE];u16 devstatus;u32 port_status;int ep0state;unsigned got_irq : 1;unsigned req_std : 1;unsigned req_config : 1;unsigned req_pending : 1;u8 vbus;struct dentry *regs_info;};
USB从设备测分析. 首先我们要知道把usb 运行于client角色时, 它的USB控制器是运行在otg模式,
USB OTG标准在完全兼容USB2.0标准的基础之上, 它允许设备既可以做为主机, 也可作为外设操作,
而此时控制USB设备控制器的驱动称之为UDC驱动, 我们记得HOST模式下控制USB设备控制器的是:USB主机控制器驱动.
这些概念比较多.只要我们理清楚就容易理解了.
UDC之上就是Gadget api .再之上就是gadeget 驱动.
USB OTG的设备控制器被抽象为:"
struct s3c2410_udc {
spinlock_t lock;
struct s3c2410_ep ep[S3C2410_ENDPOINTS];
int address;
struct usb_gadget gadget;
struct usb_gadget_driver *driver;
struct s3c2410_request fifo_req;
u8 fifo_buf[EP_FIFO_SIZE];
u16 devstatus;
u32 port_status;
int ep0state;
unsigned got_irq : 1;
unsigned req_std : 1;
unsigned req_config : 1;
unsigned req_pending : 1;
u8 vbus;
struct dentry *regs_info;
};
/*---------------------------------------------------------------------------*/
static struct s3c2410_udc memory = {
.gadget = {
.ops = &s3c2410_ops,
.ep0 = &memory.ep[0].ep,
.name = gadget_name,
.dev = {
.init_name = "gadget",
},
},
/* control endpoint */
.ep[0] = {
.num = 0,
.ep = {
.name = ep0name,
.ops = &s3c2410_ep_ops,
.maxpacket = EP0_FIFO_SIZE,
},
.dev = &memory,
},
/* first group of endpoints */
.ep[1] = {
.num = 1,
.ep = {
.name = "ep1-bulk",
.ops = &s3c2410_ep_ops,
.maxpacket = EP_FIFO_SIZE,
},
.dev = &memory,
.fifo_size = EP_FIFO_SIZE,
.bEndpointAddress = 1,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
},
.ep[2] = {
.num = 2,
.ep = {
.name = "ep2-bulk",
.ops = &s3c2410_ep_ops,
.maxpacket = EP_FIFO_SIZE,
},
.dev = &memory,
.fifo_size = EP_FIFO_SIZE,
.bEndpointAddress = 2,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
},
.ep[3] = {
.num = 3,
.ep = {
.name = "ep3-bulk",
.ops = &s3c2410_ep_ops,
.maxpacket = EP_FIFO_SIZE,
},
.dev = &memory,
.fifo_size = EP_FIFO_SIZE,
.bEndpointAddress = 3,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
},
.ep[4] = {
.num = 4,
.ep = {
.name = "ep4-bulk",
.ops = &s3c2410_ep_ops,
.maxpacket = EP_FIFO_SIZE,
},
.dev = &memory,
.fifo_size = EP_FIFO_SIZE,
.bEndpointAddress = 4,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
}
};
usb_add_function .
为configuration 添加一个或一个以上的functions, 添加过程条用@bind 函数.
比如下面添加下面的adb
static int adb_bind_config(struct usb_configuration *c)
{
struct adb_dev *dev = _adb_dev;
printk(KERN_INFO "adb_bind_config\n");
dev->cdev = c->cdev;
dev->function.name = "adb";
dev->function.descriptors = fs_adb_descs;
dev->function.hs_descriptors = hs_adb_descs;
dev->function.bind = adb_function_bind;
dev->function.unbind = adb_function_unbind;
dev->function.set_alt = adb_function_set_alt;
dev->function.disable = adb_function_disable;
return usb_add_function(c, &dev->function);
}
这里dev->function.bind = adb_function_bind; 把bind函数的进行了赋值
下面在调用
usb_add_function
这个函数时会调用这个bind函数 ,不信往下看
/**
* usb_add_function() - add a function to a configuration
* @config: the configuration
* @function: the function being added
* Context: single threaded during gadget setup
*
* After initialization, each configuration must have one or more
* functions added to it. Adding a function involves calling its @bind()
* method to allocate resources such as interface and string identifiers
* and endpoints.
*
* This function returns the value of the function's bind(), which is
* zero for success else a negative errno value.
*/
int usb_add_function(struct usb_configuration *config,
struct usb_function *function)
{
int value = -EINVAL;
DBG(config->cdev, "adding '%s'/%p to config '%s'/%p\n",
function->name, function,
config->label, config);
if (!function->set_alt || !function->disable)
goto done;
function->config = config;
list_add_tail(&function->list, &config->functions);
/* REVISIT *require* function->bind? */ /*这里就在调用bind 函数就行configuration和 usb_function的绑定*/ if (function->bind) {
value = function->bind(config, function); //调用开始
if (value < 0) {
list_del(&function->list);
function->config = NULL;
}
} else
value = 0;
/* We allow configurations that don't work at both speeds.
* If we run into a lowspeed Linux system, treat it the same
* as full speed ... it's the function drivers that will need
* to avoid bulk and ISO transfers.
*/
if (!config->fullspeed && function->descriptors)
config->fullspeed = true;
if (!config->highspeed && function->hs_descriptors)
config->highspeed = true;
if (!config->superspeed && function->ss_descriptors)
config->superspeed = true;
done:
if (value)
DBG(config->cdev, "adding '%s'/%p --> %d\n",
function->name, function, value);
return value;
}
看上面的这部分代码,. 就是调用了dev->function.bind = adb_function_bind; 这个函数进行functions 和configuration的绑定.
再看下 usb_function .
那这个 usb_function 是什么作用呢?
看下面的介绍
/**
* struct usb_function - describes one function of a configuration
* @name: For diagnostics, identifies the function.
* @strings: tables of strings, keyed by identifiers assigned during bind()
* and by language IDs provided in control requests
* @descriptors: Table of full (or low) speed descriptors, using interface and
* string identifiers assigned during @bind(). If this pointer is null,
* the function will not be available at full speed (or at low speed).
* @hs_descriptors: Table of high speed descriptors, using interface and
* string identifiers assigned during @bind(). If this pointer is null,
* the function will not be available at high speed.
* @ss_descriptors: Table of super speed descriptors, using interface and
* string identifiers assigned during @bind(). If this
* pointer is null after initiation, the function will not
* be available at super speed.
* @config: assigned when @usb_add_function() is called; this is the
* configuration with which this function is associated.
* @bind: Before the gadget can register, all of its functions bind() to the
* available resources including string and interface identifiers used
* in interface or class descriptors; endpoints; I/O buffers; and so on.
* @unbind: Reverses @bind; called as a side effect of unregistering the
* driver which added this function.
* @set_alt: (REQUIRED) Reconfigures altsettings; function drivers may
* initialize usb_ep.driver data at this time (when it is used).
* Note that setting an interface to its current altsetting resets
* interface state, and that all interfaces have a disabled state.
* @get_alt: Returns the active altsetting. If this is not provided,
* then only altsetting zero is supported.
* @disable: (REQUIRED) Indicates the function should be disabled. Reasons
* include host resetting or reconfiguring the gadget, and disconnection.
* @setup: Used for interface-specific control requests.
* @suspend: Notifies functions when the host stops sending USB traffic.
* @resume: Notifies functions when the host restarts USB traffic.
* @get_status: Returns function status as a reply to
* GetStatus() request when the recepient is Interface.
* @func_suspend: callback to be called when
* SetFeature(FUNCTION_SUSPEND) is reseived
*
* A single USB function uses one or more interfaces, and should in most
* cases support operation at both full and high speeds. Each function is
* associated by @usb_add_function() with a one configuration; that function
* causes @bind() to be called so resources can be allocated as part of
* setting up a gadget driver. Those resources include endpoints, which
* should be allocated using @usb_ep_autoconfig().
*
* To support dual speed operation, a function driver provides descriptors
* for both high and full speed operation. Except in rare cases that don't
* involve bulk endpoints, each speed needs different endpoint descriptors.
*
* Function drivers choose their own strategies for managing instance data.
* The simplest strategy just declares it "static', which means the function
* can only be activated once. If the function needs to be exposed in more
* than one configuration at a given speed, it needs to support multiple
* usb_function structures (one for each configuration).
*
* A more complex strategy might encapsulate a @usb_function structure inside
* a driver-specific instance structure to allows multiple activations. An
* example of multiple activations might be a CDC ACM function that supports
* two or more distinct instances within the same configuration, providing
* several independent logical data links to a USB host.
*/
