ark1668ed芯片USB使用说明：

一、uboot阶段支持U盘升级
	1、uboot配置中添加USB选项（默认已添加）：
		1、ARM architecture  --->
			[] usb support				//暂未使用，待后续拓展

		2、Command line interface  --->
			Device access commands  --->
				[*] usb

		3、Device Drivers  --->
				[*] USB support  --->
					--- USB support
					[*]   DesignWare USB2 Core support
					(64)    Data buffer size in kB
					[*]   USB Mass Storage support
					(1000) Timeout in milliseconds for USB HUB connection

	2、uboot设备树中添加USB配置参数（默认已添加）：
		由于USB初始化时间过长，所以默认只添加了一路USB0。
		路径：u-boot/arch/arm/dts/ark1668ed_${BOARD_TYPE}.dts	//BOARD_TYPE为devb（nand版本）或者devb_emmc（emmc版本）。

		配置如下：
			usb0_phy: usb0-phy {
				status = "okay";
			};

			usb0: usb@40000000 {
				compatible = "snps,dwc2";
				#address-cells = <1>;
				#size-cells = <0>;
				reg = <0x40000000 0x40000>;
				interrupts = <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>;
				phys = <&usb0_phy>;
				phy-names = "usb0-phy";
				dr_mode = "host";
				status = "okay";
			};

二、内核中配置USB
	1、linux内核配置中添加USB选项（默认已添加）：
		Device Drivers
			[*] USB support  --->
				<*>   Support for Host-side USB
				[*]   Enable USB persist by default
				(2)   Default autosuspend delay
				(1)   Default authorization mode for USB devices
				<*>   USB Mass Storage support
				<*>     USB Attached SCSI
				<M>   DesignWare USB2 DRD Core Support			//【为加快开机启动时间，此处配置为ko模式】
						DWC2 Mode Selection (Dual Role mode)  --->
				<*>   USB Gadget Support  --->
						--- USB Gadget Support
						(2)   Maximum VBUS Power usage (2-500 mA) 
						(2)   Number of storage pipeline buffers
						<*>   USB Gadget functions configurable through configfs
						[*]     Network Control Model (CDC NCM)
						[*]     USB Gadget Target iap2 gadget
						[*]     USB Gadget Target adb gadget

	2、linux内核配置设备树文件（默认已添加）：
		根据需要修改linux/arch/arm/boot/dts/arkmicro/ark1668ed.dtsi文件中的usb和usb phy的配置。

		配置如下：
			usb0_phy: usb0-phy {
				compatible = "usb-nop-xceiv";
				#phy-cells = <0>; 
				status = "OK";
			};
		 
			usb1_phy: usb1-phy {
				compatible = "usb-nop-xceiv";
				#phy-cells = <0>; 
				status = "OK";
			};

			usb0: usb@40000000 {
				......
				//status = "disabled";	//默认USB0开启,屏蔽USB0则配置status = "disabled"
			};

			usb1: usb@40c00000 {
				......
				//status = "disabled";	//默认USB1开启,屏蔽USB1则配置status = "disabled"
			};


三、编译并升级系统
	升级操作参考 "doc/升级说明.txt"。

四、进入系统后加载驱动并挂载U盘
	第一步：加载USB驱动
			insmod /1ib/modules/6.12.16/kernel/drivers/usb/dwc2/dwc2.ko

	第二步：置otg
			待完善（暂时忽略）

		此时插拔U盘，在/dev/目录下会有节点生成：/dev/sd*

		插入U盘log参考如下：
			/ # dmesg -c
				usb 1-1: new high-speed USB device number 2 using dwc2
				usb-storage 1-1:1.0: USB Mass Storage device detected
				scsi host0: usb-storage 1-1:1.0
				scsi 0:0:0:0: Direct-Access     Multiple Card  Reader     1.00 PQ: 0 ANSI: 0
				sd 0:0:0:0: Attached scsi generic sg0 type 0
				sd 0:0:0:0: [sda] 30539776 512-byte logical blocks: (15.6 GB/14.6 GiB)
				sd 0:0:0:0: [sda] Write Protect is off
				sd 0:0:0:0: [sda] Mode Sense: 03 00 00 00
				sd 0:0:0:0: [sda] No Caching mode page found
				sd 0:0:0:0: [sda] Assuming drive cache: write through
				sda:
				sd 0:0:0:0: [sda] Attached SCSI removable disk
				FAT-fs (sda): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.
		拔掉U盘log参考如下：
			/ # dmesg -c
				usb 1-1: USB disconnect, device number 2

	第三步：手动挂载测试（按照上述参考节点：/dev/sda）
		命令：mount /dev/sda /mnt

		挂载成功后可以看到U盘下的文件。

五、启动ncm模式
	切换为device模式，详细参考build_ncm_iap.sh脚本，如下所示：
	
	/# vi build_ncm_iap.sh
		#!/bin/sh

		if [ $# -eq 0 ];
		then
			usb_idx=0
		else
			usb_idx=1
		fi

		# config ncm function
		KER_CONF="`grep '/sys/kernel/config' /proc/mounts`"
		if  [ -z "$KER_CONF" ];  then
			mount -t configfs none /sys/kernel/config
		fi

		if  [ ! -d /sys/kernel/config/usb_gadget/g1 ];  then
			mkdir /sys/kernel/config/usb_gadget/g1
		fi

		if  [ ! -d /sys/kernel/config/usb_gadget/g1/strings/0x409 ];  then
			mkdir /sys/kernel/config/usb_gadget/g1/strings/0x409
		fi

		if  [ ! -d /sys/kernel/config/usb_gadget/g1/functions/ncm.g1 ];  then
			mkdir /sys/kernel/config/usb_gadget/g1/functions/ncm.g1
		fi

		#if  [ ! -d /sys/kernel/config/usb_gadget/g1/functions/iap.g1 ];  then
		#    mkdir /sys/kernel/config/usb_gadget/g1/functions/iap.g1
		#fi

		if  [ ! -d /sys/kernel/config/usb_gadget/g1/configs/c.1 ];  then
			mkdir /sys/kernel/config/usb_gadget/g1/configs/c.1
		fi

		if  [ ! -d /sys/kernel/config/usb_gadget/g1/configs/c.1/strings/0x409 ];  then
			mkdir /sys/kernel/config/usb_gadget/g1/configs/c.1/strings/0x409
		fi

		echo "0x0525" > /sys/kernel/config/usb_gadget/g1/idVendor
		echo "0xa4a1" > /sys/kernel/config/usb_gadget/g1/idProduct

		echo "012345678adcdef" > /sys/kernel/config/usb_gadget/g1/strings/0x409/serialnumber
		echo "Arkmicro.Inc" > /sys/kernel/config/usb_gadget/g1/strings/0x409/manufacturer
		echo "Ark1668e USB Device" > /sys/kernel/config/usb_gadget/g1/strings/0x409/product

		echo 0xc0 > /sys/kernel/config/usb_gadget/g1/configs/c.1/bmAttributes
		echo 500 > /sys/kernel/config/usb_gadget/g1/configs/c.1/MaxPower

		if  [ ! -L /sys/kernel/config/usb_gadget/g1/configs/c.1/ncm.g1 ];  then
			ln -s /sys/kernel/config/usb_gadget/g1/functions/ncm.g1/ /sys/kernel/config/usb_gadget/g1/configs/c.1/ncm.g1
		fi

		#if  [ ! -L /sys/kernel/config/usb_gadget/g1/configs/c.1/iap.g1 ];  then
		#    ln -s /sys/kernel/config/usb_gadget/g1/functions/iap.g1/ /sys/kernel/config/usb_gadget/g1/configs/c.1/iap.g1
		#fi

		#ls /sys/class/udc
		# enable udc
		#echo 70300000.usb > /sys/kernel/config/usb_gadget/g1/UDC
		if [ $usb_idx -eq 0 ];
		then
				echo 40000000.usb > /sys/kernel/config/usb_gadget/g1/UDC
				sleep 0.1
				echo device > /sys/class/usb_role/40000000.usb-role-switch/role
		else
				echo 40c00000.usb > /sys/kernel/config/usb_gadget/g1/UDC
				sleep 0.1
				echo device > /sys/class/usb_role/40c00000.usb-role-switch/role
		fi