4.7 USB Device测试
本例程演示使用开发板的Micro USB接口(J7)作为Device模式，可以将指定的文件或设备模拟为设备，连接到其它USB HOST设备。这里把内存作为存储设备提供给HOST设备。
- 开发板上使用modprobe加载驱动:
mkfs.vfat /dev/ram1
modprobe g_mass_storage.ko file=/dev/ram1 removable=1 \
iSerialNumber="1234"
[ 3048.950498] Mass Storage Function, version: 2009/09/11
[ 3048.982245] LUN: removable file: (no medium)
[ 3048.997849] LUN: removable file: /dev/ram1
[ 3049.000674] Number of LUNs=1
[ 3049.002272] Number of LUNs=1
[ 3049.023990] g_mass_storage gadget: Mass Storage Gadget,
version: 2009/09/11
[ 3049.029682] g_mass_storage gadget: g_mass_storage ready
[ 3094.766373] g_mass_storage gadget: high-speed config
#1: Linux File-Backed Storage
- Linux PC机上查看到有USB设备接入，SerialNumber为"1234"，Manufacturer是内核构建版本号:
dmesg | tail -n 20
[2872436.778616] usb 1-1: USB disconnect, device number 102
[2872436.779156] sd 3:0:0:0: [sdb] Synchronizing SCSI cache
[2872436.779201] sd 3:0:0:0: [sdb] Synchronize Cache(10)
failed: Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK
[2872442.508567] usb 1-1: new high-speed USB device number 103
using xhci_hcd
[2872442.650549] usb 1-1: New USB device found, idVendor=0525,
idProduct=a4a5
[2872442.650551] usb 1-1: New USB device strings: Mfr=3, Produ
ct=4, SerialNumber=5
[2872442.650552] usb 1-1: Product: Mass Storage Gadget
[2872442.650553] usb 1-1: Manufacturer: Linux 4.1.15-1.2.0+g8d9
8da6 with 2184000.usb
[2872442.650554] usb 1-1: SerialNumber: 1234
[2872442.657827] usb-storage 1-1:1.0: USB Mass Storage device
detected
[2872442.657895] usb-storage 1-1:1.0: Quirks match for vid 0525
pid a4a5: 10000
[2872442.657923] scsi host3: usb-storage 1-1:1.0
[2872443.669426] scsi 3:0:0:0: Direct-Access Linux File-
Stor Gadget 0401 PQ: 0 ANSI: 2
[2872443.669886] sd 3:0:0:0: Attached scsi generic sg1 type 0
[2872443.670820] sd 3:0:0:0: [sdb] 131072 512-byte logical blocks:
(67.1 MB/64.0 MiB)
[2872443.779976] sd 3:0:0:0: [sdb] Write Protect is off
[2872443.779979] sd 3:0:0:0: [sdb] Mode Sense: 0f 00 00 00
[2872443.890093] sd 3:0:0:0: [sdb] Write cache: enabled, read cache:
enabled, doesn't support DPO or FUA
[2872444.110372] sdb:
[2872444.330074] sd 3:0:0:0: [sdb] Attached SCSI removable disk