USB总线-Linux内核USB3.0设备控制器复合设备之USB gadget configfs分析（七）

#!/bin/bash
function start_uac2()
{
	# usb_gadget依赖于libcomposite模块
	modprobe libcomposite
	# 挂载config文件系统
	mount -t configfs none /sys/kernel/config

	# 创建g1目录，实例化一个新的gadget模板
	
	echo "mkdir /sys/kernel/config/usb_gadget/g1"
	mkdir -m 0770 /sys/kernel/config/usb_gadget/g1

	# 设置产品的VendorID、ProductID及USB规范版本号
	echo "Setting Vendor Product ID's and bcdDevice"
	echo 0x2207 > /sys/kernel/config/usb_gadget/g1/idVendor
	echo 0x0019 > /sys/kernel/config/usb_gadget/g1/idProduct
	# 设备版本号
	echo 0x0200 > /sys/kernel/config/usb_gadget/g1/bcdDevice
	# USB 1.1: 0x0110
	# USB 2.0: 0x0200, USB 2.1: 0x0210, USB 2.5: 0x0250
	# USB 3.0: 0x0300, USB 3.1: 0x0310, USB 3.2: 0x0320
	# echo 0x0210 > /sys/kernel/config/usb_gadget/g1/bcdUSB
	
	# 实例化英语ID，开发商、产品和序列号字符串写入内核
	echo "Setting English strings"
	mkdir -m 0770 /sys/kernel/config/usb_gadget/g1/strings/0x409
	echo "0123456789ABCDEF" > /sys/kernel/config/usb_gadget/g1/strings/0x409/serialnumber
	echo "rockchip"  > /sys/kernel/config/usb_gadget/g1/strings/0x409/manufacturer
	echo "USB Audio Device"  > /sys/kernel/config/usb_gadget/g1/strings/0x409/product

	# Creating Config
	echo "Creating Config"
	mkdir -m 0770 /sys/kernel/config/usb_gadget/g1/configs/c.1
	mkdir -m 0770 /sys/kernel/config/usb_gadget/g1/configs/c.1/strings/0x409
	echo "uac2" > /sys/kernel/config/usb_gadget/g1/configs/c.1/strings/0x409/configuration
	echo 500 > /sys/kernel/config/usb_gadget/g1/configs/c.1/MaxPower

	 
	# bind functions
	# uac2 need to put before uvc, otherwise uvc + uac2 enumerate failed in win10
	echo "Creating UAC2 gadget functionality : uac2.0"
	mkdir /sys/kernel/config/usb_gadget/g1/functions/uac2.0
	ln -s /sys/kernel/config/usb_gadget/g1/functions/uac2.0 /sys/kernel/config/usb_gadget/g1/configs/c.1

	# Binding USB Device Controller
	echo "Binding USB Device Controller"
	echo fe800000.dwc3 > /sys/kernel/config/usb_gadget/g1/UDC
}

function stop_uac2()
{
	# Disabling the gadget
	echo "Disabling the USB gadget"
	echo "" > /sys/kernel/config/usb_gadget/g1/UDC

	# Remove functions from configurations
	rm /sys/kernel/config/usb_gadget/g1/configs/c.1/uac2.0
	# Remove strings directories in configurations
	rmdir /sys/kernel/config/usb_gadget/g1/configs/c.1/strings/0x409
	# remove the configurations
	rmdir /sys/kernel/config/usb_gadget/g1/configs/c.1

	# Remove functions (function modules are not unloaded, though)
	rmdir /sys/kernel/config/usb_gadget/g1/functions/uac2.0

	# Remove strings directories in the gadget
	rmdir /sys/kernel/config/usb_gadget/g1/strings/0x409

	# finally remove the gadget
	rmdir /sys/kernel/config/usb_gadget/g1
}

usage()
{
    echo "Usage: ./usb-gadget-uac2.sh start|stop"
    echo " options:"
    echo "    start           start uac2.0 gadget"
    echo "    stop            stop uac2.0 gadget"
}

case $1 in
start)
	start_uac2
	;;
stop)
	stop_uac2
	;;
*)
	usage
	exit 1
	;;
esac
exit 0

├── bcdDevice
├── bcdUSB
├── bDeviceClass
├── bDeviceProtocol
├── bDeviceSubClass
├── bMaxPacketSize0
├── configs
│   └── c.1
│       ├── bmAttributes
│       ├── MaxPower
│       ├── strings
│       │   └── 0x409
│       │       └── configuration
│       └── uac2.0 -> ../../../../usb_gadget/g1/functions/uac2.0
├── functions
│   └── uac2.0
│       ├── c_chmask      # 录音通道掩码，默认0x3
│       ├── c_srate       # 录音采样率，默认64000
│       ├── c_ssize       # 录音一帧数据所占bit位，默认16bit
│       ├── p_chmask      # 播放通道掩码，默认0x3
│       ├── p_srate       # 播放采样率，默认48000
│       ├── p_ssize       # 播放一帧数据所占bit位，默认16bit
│       └── req_number    # 分配usb请求数量，默认2个
├── idProduct
├── idVendor
├── os_desc
│   ├── b_vendor_code
│   ├── qw_sign
│   └── use
├── strings
│   └── 0x409
│       ├── manufacturer
│       ├── product
│       └── serialnumber
└── UDC    # 用于设置绑定USB控制器的名称

[drivers/usb/gadget/configfs.c]
static struct configfs_group_operations gadgets_ops = {
	.make_group     = &gadgets_make,
	.drop_item      = &gadgets_drop,
};

static struct config_item_type gadgets_type = {
	.ct_group_ops   = &gadgets_ops,
	.ct_owner       = THIS_MODULE,
};

static struct configfs_subsystem gadget_subsys = {
	.su_group = {
		.cg_item = {
			.ci_namebuf = "usb_gadget",
			.ci_type = &gadgets_type,
		},
	},
	.su_mutex = __MUTEX_INITIALIZER(gadget_subsys.su_mutex),
};
static int __init gadget_cfs_init(void)
{
	int ret;
	config_group_init(&gadget_subsys.su_group);
	ret = configfs_register_subsystem(&gadget_subsys);
#ifdef CONFIG_USB_CONFIGFS_UEVENT
	android_class = class_create(THIS_MODULE, "android_usb");
	if (IS_ERR(android_class))
		return PTR_ERR(android_class);
#endif
	return ret;
}
module_init(gadget_cfs_init);

[drivers/usb/gadget/configfs.c]
static struct configfs_group_operations gadgets_ops = {
	.make_group     = &gadgets_make,
	.drop_item      = &gadgets_drop,
};

static struct config_item_type gadgets_type = {
	.ct_group_ops   = &gadgets_ops,
	.ct_owner       = THIS_MODULE,
};

static struct configfs_subsystem gadget_subsys = {
	.su_group = {
		.cg_item = {
			.ci_namebuf = "usb_gadget",
			.ci_type = &gadgets_type,
		},
	},
	.su_mutex = __MUTEX_INITIALIZER(gadget_subsys.su_mutex),
};
static int __init gadget_cfs_init(void)
{
	int ret;
	config_group_init(&gadget_subsys.su_group);
	ret = configfs_register_subsystem(&gadget_subsys);
#ifdef CONFIG_USB_CONFIGFS_UEVENT
	android_class = class_create(THIS_MODULE, "android_usb");
	if (IS_ERR(android_class))
		return PTR_ERR(android_class);
#endif
	return ret;
}
module_init(gadget_cfs_init);

[drivers/usb/gadget/configfs.c]
static struct config_group *gadgets_make(
		struct config_group *group, const char *name)
{
    ......
    /* 分配struct gadget_info结构体 */
    gi = kzalloc(sizeof(*gi), GFP_KERNEL);
    ......
	/* 设置group，gadgets_make最终返回的是gi->group */
	gi->group.default_groups = gi->default_groups;
	gi->group.default_groups[0] = &gi->functions_group;
	gi->group.default_groups[1] = &gi->configs_group;
	gi->group.default_groups[2] = &gi->strings_group;
	gi->group.default_groups[3] = &gi->os_desc_group;

    /* 设置functions_group，可配置function驱动的参数 */
	config_group_init_type_name(&gi->functions_group, "functions",
			&functions_type);
    /* 设置configs_group，可配置USB设备参数 */
	config_group_init_type_name(&gi->configs_group, "configs",
			&config_desc_type);
    /* 设置strings_group，可配置字符串参数 */
	config_group_init_type_name(&gi->strings_group, "strings",
			&gadget_strings_strings_type);
    /* 设置os_desc_group，可配置操作系统描述符 */
	config_group_init_type_name(&gi->os_desc_group, "os_desc",
			&os_desc_type);

	/* 初始化复合设备驱动-usb_composite_driver */
	gi->composite.bind = configfs_do_nothing;    // 实现为空
	gi->composite.unbind = configfs_do_nothing;  // 实现为空
	gi->composite.suspend = NULL;
	gi->composite.resume = NULL;
	gi->composite.max_speed = USB_SPEED_SUPER;   // 支持USB3.0

	/* 初始化复合设备-usb_composite_dev */
	composite_init_dev(&gi->cdev);
	/* 设置复合设备描述符 */
	gi->cdev.desc.bLength = USB_DT_DEVICE_SIZE;
	gi->cdev.desc.bDescriptorType = USB_DT_DEVICE;
	gi->cdev.desc.bcdDevice = cpu_to_le16(get_default_bcdDevice());

	/* 设置configfs的usb_gadget_driver */
	gi->composite.gadget_driver = configfs_driver_template;
	gi->composite.gadget_driver.function = kstrdup(name, GFP_KERNEL);
	gi->composite.name = gi->composite.gadget_driver.function;

	/* 设置config_group */
	config_group_init_type_name(&gi->group, name,
				&gadget_root_type);
	/* 向configfs系统返回&gi->group */
	return &gi->group;
}
/* usb gadget configfs定义的usb_gadget_driver */
static const struct usb_gadget_driver configfs_driver_template = {
	.bind           = configfs_composite_bind,
	.unbind         = configfs_composite_unbind,
#ifdef CONFIG_USB_CONFIGFS_UEVENT
	.setup          = android_setup,
	.reset          = android_disconnect,
	.disconnect     = android_disconnect,
#else
	.setup          = composite_setup,
	.reset          = composite_disconnect,
	.disconnect     = composite_disconnect,
#endif
	.suspend	    = composite_suspend,
	.resume		    = composite_resume,

	.max_speed	    = USB_SPEED_SUPER,
	.driver = {
		.owner      = THIS_MODULE,
		.name		= "configfs-gadget",
	},
};

[drivers/usb/gadget/configfs.c]
static struct configfs_attribute *gadget_root_attrs[] = {
	&gadget_dev_desc_attr_bDeviceClass,
	&gadget_dev_desc_attr_bDeviceSubClass,
	&gadget_dev_desc_attr_bDeviceProtocol,
	&gadget_dev_desc_attr_bMaxPacketSize0,
	&gadget_dev_desc_attr_idVendor,
	&gadget_dev_desc_attr_idProduct,
	&gadget_dev_desc_attr_bcdDevice,
	&gadget_dev_desc_attr_bcdUSB,
	&gadget_dev_desc_attr_UDC,
	NULL,
};
static struct config_item_type gadget_root_type = {
	.ct_item_ops	= &gadget_root_item_ops,
	.ct_attrs	= gadget_root_attrs,
	.ct_owner	= THIS_MODULE,
};


static struct configfs_group_operations functions_ops = {
	.make_group     = &function_make,
	.drop_item      = &function_drop,
};
static struct config_item_type functions_type = {
	.ct_group_ops   = &functions_ops,
	.ct_owner       = THIS_MODULE,
};


static struct configfs_group_operations config_desc_ops = {
	.make_group     = &config_desc_make,
	.drop_item      = &config_desc_drop,
};
static struct config_item_type config_desc_type = {
	.ct_group_ops   = &config_desc_ops,
	.ct_owner       = THIS_MODULE,
};


/* 定义gadget_strings_strings_type的宏 */
USB_CONFIG_STRINGS_LANG(gadget_strings, gadget_info);
[include/linux/usb/gadget_configfs.h]
#define USB_CONFIG_STRINGS_LANG(struct_in, struct_member)	\
	......                                                   \
static struct configfs_group_operations struct_in##_strings_ops = {	\
	.make_group     = &struct_in##_strings_make,			\
	.drop_item      = &struct_in##_strings_drop,			\
};									\
									\
static struct config_item_type struct_in##_strings_type = {		\
	.ct_group_ops   = &struct_in##_strings_ops,			\
	.ct_owner       = THIS_MODULE,					\
}


static struct configfs_item_operations os_desc_ops = {
	.release        = os_desc_attr_release,
	.allow_link		= os_desc_link,
	.drop_link		= os_desc_unlink,
};
static struct config_item_type os_desc_type = {
	.ct_item_ops	= &os_desc_ops,
	.ct_attrs	= os_desc_attrs,
	.ct_owner	= THIS_MODULE,
};