【米尔瑞萨RZ/G2L开发板-创新应用】qemu 虚拟 usb gadget 驱动开发环境搭建
qemu 虚拟 gadget 驱动开发环境搭建因为我的项目主要是围绕 usb gadget 驱动进行开发的，加上最近一段时间出差手边没有板子，所以本
篇就记录下在没有板子的情况下如何进行程序开发调试。
本次，我实现的效果是使用最新版的 qemu-system-arm 模拟 orangepi PC 这个虚拟板卡，并手动编译
内核和根文件系统。同时引导启动。
环境
本次，我使用的环境：
PC 环境是 Linux fedora 6.1.14-100.fc36.x86_64
qemu 版本(手动编译的最新版本) QEMU emulator version 8.1.50 (v8.1.0-549-
gc5ea91da44)
orangepi-PC 对应的内核版本是 5.4.65
orangepi-PC 使用的根文件系统，使用最新版本的 buildroot 进行构建
过程
1. qemu 的编译过程,这里需要注意，我开始编译的时候没有生成 qemu-system-arm 工具，后来发现
是没有使能 -enable-system,同时因为后续会使用到 -nic 的 user 模式，所以这里还要在 PC 端
安装相关的软件包 libslirp-devel 。最后，完整的配置命令是 ./configure --target-
list='aarch64-linux-user arm-linux-user arm-softmmu aarch64-softmmu' --enable-
tools --enable-linux-user --enable-system --enable-slirp --enable-kvm
2. orangepi-PC 内核的编译过程相对就简单了，参数 orangepi-PC 根据OrangePi_PC_H3
用户手册
v3.2.pdf 这份文档，可以找对对应内核的仓库和对应的交叉编译器, 配置就选择仓库的
orangepi_defconfig 进行编译就行，中间出现部分错误提示有些文件(regulatory.db
regulatory.db.p7s)找不到，从 github 找到对应的文件，另外的文件(edid/asus.bin)我在配置
过程中给删除了(因为我没有从网上找到)。然后就可以顺利编译通过了。
...
MODPOST 3 modules
CC drivers/usb/gadget/legacy/g_serial.mod.o
CC drivers/usb/gadget/legacy/g_zero.mod.o
Kernel: arch/arm/boot/Image is ready
CC drivers/usb/gadget/udc/dummy_hcd.mod.o
LD drivers/usb/gadget/legacy/g_serial.ko
LD drivers/usb/gadget/legacy/g_zero.ko
LZ4 arch/arm/boot/compressed/piggy_data
LD drivers/usb/gadget/udc/dummy_hcd.ko
CC arch/arm/boot/compressed/decompress.o
AS arch/arm/boot/compressed/piggy.o
LD arch/arm/boot/compressed/vmlinux
OBJCOPY arch/arm/boot/zImage
Kernel: arch/arm/boot/zImage is ready
3. 构建根文件系统的时候，为了加快构建，选择使用先安装好的工具链，不编译内核和bootloader,
如果本地有 buildroot 的相关下载源，那么可以加快下载构建的过程。构建成功后会生成
rootfs.ext2 文件。接着使用下面的脚本将文件转换为 ramdisk 模式（记得在内核配置过程中
也要放开选项 CONFIG_BLK_DEV_RAM , 以及 CONFIG_BLK_DEV_RAM_SIZE ）
...
Creating regular file
/home/red/Downloads/qemu_gadget/orangpi_pc_software/buildroot/output/images/rootf
s.ext2
64-bit filesystem support is not enabled. The larger fields afforded by this
feature enable full-strength checksumming. Pass -O 64bit to rectify.
Creating filesystem with 61440 1k blocks and 15360 inodes
Filesystem UUID: 709417d3-e230-4a1e-888c-8ef34bf4f014
Superblock backups stored on blocks:
8193, 24577, 40961, 57345
Allocating group tables: done
Writing inode tables: done
Creating journal (4096 blocks): done
Copying files into the device: done
Writing superblocks and filesystem accounting information: done
ln -sf rootfs.ext2
/home/red/Downloads/qemu_gadget/orangpi_pc_software/buildroot/output/images/rootf
s.ext4
测试
接着就是完事具备，测试引导启动了，启动命令为： qemu-system-arm -M orangepi-pc -nic user -
nographic -kernel arch/arm/boot/zImage -append 'console=ttyS0,115200 nosmp
root=/dev/ram' -dtb arch/arm/boot/dts/sun8i-h3-orangepi-pc.dtb -initrd rootfs.ext2(根
文件系统的完整路径) 正常的启动打印信息如下：
Booting Linux on physical CPU 0x0
Linux version 5.4.65-g018b9c0bc2d5-dirty (red@fedora) (gcc version 9.2.1 20191025
(GNU Toolchain for the A-profile Architecture 9.2-2019.12 (arm-9.10))) #6 SMP Sun
Sep 10 20:28:01 CST 2023
CPU: ARMv7 Processor revision 5 (ARMv7), cr=30c5387d
CPU: div instructions available: patching division code
CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
OF: fdt: Machine model: Xunlong Orange Pi PC
Memory policy: Data cache writealloc
cma: Reserved 128 MiB at 0x0000000078000000
On node 0 totalpages: 262144
Normal zone: 2304 pages used for memmap
Normal zone: 0 pages reserved
Normal zone: 196608 pages, LIFO batch:63
HighMem zone: 65536 pages, LIFO batch:15
...
sun8i-h3-pinctrl 1c20800.pinctrl: 1c20800.pinctrl supply vcc-pg not found, using
dummy regulator
ehci-platform 1c1b000.usb: EHCI Host Controller
ehci-platform 1c1b000.usb: new USB bus registered, assigned bus number 5
ehci-platform 1c1b000.usb: irq 28, io mem 0x01c1b000
ehci-platform 1c1b000.usb: USB 2.0 started, EHCI 1.00
usb usb5: New USB device found, idVendor=1d6b, idProduct=0002, bcdDevice= 5.04
usb usb5: New USB device strings: Mfr=3, Product=2, SerialNumber=1
usb usb5: Product: EHCI Host Controller
usb usb5: Manufacturer: Linux 5.4.65-g018b9c0bc2d5-dirty ehci_hcd
usb usb5: SerialNumber: 1c1b000.usb
hub 5-0:1.0: USB hub found
hub 5-0:1.0: 6 ports detected
ehci-platform 1c1c000.usb: EHCI Host Controller
ehci-platform 1c1c000.usb: new USB bus registered, assigned bus number 6
ehci-platform 1c1c000.usb: irq 30, io mem 0x01c1c000
ehci-platform 1c1c000.usb: USB 2.0 started, EHCI 1.00
usb usb6: New USB device found, idVendor=1d6b, idProduct=0002, bcdDevice= 5.04
usb usb6: New USB device strings: Mfr=3, Product=2, SerialNumber=1
usb usb6: Product: EHCI Host Controller
usb usb6: Manufacturer: Linux 5.4.65-g018b9c0bc2d5-dirty ehci_hcd
usb usb6: SerialNumber: 1c1c000.usb
hub 6-0:1.0: USB hub found
hub 6-0:1.0: 6 ports detected
ehci-platform 1c1d000.usb: EHCI Host Controller
ehci-platform 1c1d000.usb: new USB bus registered, assigned bus number 7
ehci-platform 1c1d000.usb: irq 32, io mem 0x01c1d000
ehci-platform 1c1d000.usb: USB 2.0 started, EHCI 1.00
usb usb7: New USB device found, idVendor=1d6b, idProduct=0002, bcdDevice= 5.04
usb usb7: New USB device strings: Mfr=3, Product=2, SerialNumber=1
usb usb7: Product: EHCI Host Controller
usb usb7: Manufacturer: Linux 5.4.65-g018b9c0bc2d5-dirty ehci_hcd
usb usb7: SerialNumber: 1c1d000.usb
hub 7-0:1.0: USB hub found
hub 7-0:1.0: 6 ports detected
ohci-platform 1c1b400.usb: Generic Platform OHCI controller
ohci-platform 1c1b400.usb: new USB bus registered, assigned bus number 8
ohci-platform 1c1b400.usb: irq 29, io mem 0x01c1b400
usb usb8: New USB device found, idVendor=1d6b, idProduct=0001, bcdDevice= 5.04
usb usb8: New USB device strings: Mfr=3, Product=2, SerialNumber=1
usb usb8: Product: Generic Platform OHCI controller
usb usb8: Manufacturer: Linux 5.4.65-g018b9c0bc2d5-dirty ohci_hcd
usb usb8: SerialNumber: 1c1b400.usb
hub 8-0:1.0: USB hub found
hub 8-0:1.0: 3 ports detected
ohci-platform 1c1c400.usb: Generic Platform OHCI controller
ohci-platform 1c1c400.usb: new USB bus registered, assigned bus number 9
ohci-platform 1c1c400.usb: irq 31, io mem 0x01c1c400
usb usb9: New USB device found, idVendor=1d6b, idProduct=0001, bcdDevice= 5.04
usb usb9: New USB device strings: Mfr=3, Product=2, SerialNumber=1
usb usb9: Product: Generic Platform OHCI controller
usb usb9: Manufacturer: Linux 5.4.65-g018b9c0bc2d5-dirty ohci_hcd
usb usb9: SerialNumber: 1c1c400.usb
hub 9-0:1.0: USB hub found
hub 9-0:1.0: 3 ports detected
ohci-platform 1c1d400.usb: Generic Platform OHCI controller
ohci-platform 1c1d400.usb: new USB bus registered, assigned bus number 10
ohci-platform 1c1d400.usb: irq 33, io mem 0x01c1d400
usb usb10: New USB device found, idVendor=1d6b, idProduct=0001, bcdDevice= 5.04
usb usb10: New USB device strings: Mfr=3, Product=2, SerialNumber=1
usb usb10: Product: Generic Platform OHCI controller
usb usb10: Manufacturer: Linux 5.4.65-g018b9c0bc2d5-dirty ohci_hcd
usb usb10: SerialNumber: 1c1d400.usb
hub 10-0:1.0: USB hub found
hub 10-0:1.0: 3 ports detected
usb_phy_generic usb_phy_generic.0.auto: usb_phy_generic.0.auto supply vcc not
found, using dummy regulator
musb-hdrc musb-hdrc.1.auto: MUSB HDRC host driver
musb-hdrc musb-hdrc.1.auto: new USB bus registered, assigned bus number 11
usb usb11: New USB device found, idVendor=1d6b, idProduct=0002, bcdDevice= 5.04
usb usb11: New USB device strings: Mfr=3, Product=2, SerialNumber=1
usb usb11: Product: MUSB HDRC host driver
usb usb11: Manufacturer: Linux 5.4.65-g018b9c0bc2d5-dirty musb-hcd
usb usb11: SerialNumber: musb-hdrc.1.auto
hub 11-0:1.0: USB hub found
hub 11-0:1.0: 1 port detected
...
EXT4-fs (ram0): mounted filesystem with ordered data mode. Opts: (null)
VFS: Mounted root (ext4 filesystem) readonly on device 1:0.
devtmpfs: mounted
Freeing unused kernel memory: 2048K
Run /sbin/init as init process
EXT4-fs (ram0): re-mounted. Opts: (null)
Starting syslogd: OK
Starting klogd: OK
Running sysctl: OK
random: seedrng: uninitialized urandom read (256 bytes read)
Saving 2048 bits of non-creditable seed for next boot
Starting rpcbind: OK
Starting network: dwmac-sun8i 1c30000.ethernet eth0: PHY driver [Generic
PHY]
dwmac-sun8i 1c30000.ethernet eth0: No Safety Features support found
dwmac-sun8i 1c30000.ethernet eth0: No MAC Management Counters available
dwmac-sun8i 1c30000.ethernet eth0: PTP not supported by HW
dwmac-sun8i 1c30000.ethernet eth0: configuring for phy/mii link mode
dwmac-sun8i 1c30000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx
udhcpc: started, v1.36.1
udhcpc: broadcasting discover
udhcpc: broadcasting select for 10.0.2.15, server 10.0.2.2
udhcpc: lease of 10.0.2.15 obtained from 10.0.2.2, lease time 86400
deleting routers
adding dns 10.0.2.3
OK
Starting NFS statd: OK
Starting NFS services: OK
Starting NFS daemon: NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state
recovery directory
NFSD: unable to find recovery directory /var/lib/nfs/v4recovery
NFSD: Unable to initialize client recovery tracking! (-2)
NFSD: starting 90-second grace period (net f0000049)
OK
Starting NFS mountd: OK
Welcome to Buildroot for the Orange Pi PC By Red
OrangePi_PC login: random: fast init done
# uname -a
Linux OrangePi_PC 5.4.65-g018b9c0bc2d5-dirty #6 SMP Sun Sep 10 20:28:01 CST 2023
armv7l GNU/Linux
手动修改 serial.c 文件如下：
diff --git a/drivers/usb/gadget/legacy/serial.c
b/drivers/usb/gadget/legacy/serial.c
index de30d7628eef..bf7a75670c42 100644
--- a/drivers/usb/gadget/legacy/serial.c
+++ b/drivers/usb/gadget/legacy/serial.c
@@ -21,7 +21,7 @@
#define GS_VERSION_STR "v2.4"
#define GS_VERSION_NUM 0x2400
-#define GS_LONG_NAME "Gadget Serial"
+#define GS_LONG_NAME "Gadget Serial Wow"
#define GS_VERSION_NAME GS_LONG_NAME " " GS_VERSION_STR
/*-------------------------------------------------------------------------*/
@@ -42,7 +42,7 @@ USB_GADGET_COMPOSITE_OPTIONS();
#define STRING_DESCRIPTION_IDX USB_GADGET_FIRST_AVAIL_IDX
static struct usb_string strings_dev[] = {
- .s = "",
+ .s = "Red Inc",
.s = GS_VERSION_NAME,
.s = "",
.s = NULL /* updated; f(use_acm) */,
进一步测试加载驱动的打印如下：
# insmod g_serial.ko
udc usbip-vudc.0: registering UDC driver
g_serial gadget: adding 'acm'/776f8dd4 to config 'CDC ACM config'/a5c02f92
g_serial gadget: acm ttyGS0: dual speed IN/ep1in OUT/ep1out NOTIFY/ep2in
g_serial gadget: Gadget Serial Wow v2.4
g_serial gadget: g_serial ready
至此可以看出使用 qemu 调试 usbgadget 驱动成为可能（备注：qemu 模拟的 origanpi-PC 和 PC 机测试使用
的 tftp 服务传输文件）。
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