PiKVM - Open and inexpensive DIY IP-KVM on Raspberry Pi

開源項目：https://github.com/pikvm

目的：在 rk3568上實現 pikvm所有功能 ，本篇主要實現 rk3568 usb Gadget （hid，ums）

硬件：

• rk3568 / rk3399 / rk3588
• usb otg接口

開發板既要當USB OTG口既要當鍵盤，又要當鼠標使用。則要生成兩個hid：，一個鍵盤hidg0，一個鼠標hidg1。

1. 功能實現

1.1 kernel 配置

在rockchip_linux_defconfig中添加

CONFIG_USB_CONFIGFS_F_HID = y
CONFIG_USB_CONFIGFS_MASS_STORAGE=y

./build.sh 編譯kernel

./build.sh kernel

確認kernel/drivers/usb/gadget/function/f_hid.c被編譯 f_hid.o

燒錄固件boot.img 切換到loader模式

1.2 使能HID配置

進入系統后執行

echo usb_hid_en > /tmp/.usb_config & /etc/init.d/S50usbdevice restart

USB功能配置成功會有如下log，表明進入USB Ready:

[ 5662.081549] android_work: sent uevent USB_STATE=CONNECTED
[ 5662.085903] configfs-gadget gadget: high-speed config #1: b
[ 5662.086881] android_work: sent uevent USB_STATE=CONFIGURED

查看 ls -l /dev/hid*

如果需要添加兩個hid，分別做keyboard，mouse

diff --git a/external/rkscript/S50usbdevice b/external/rkscript/S50usbdevice
index 1162f296f..0ad102150 100644
--- a/external/rkscript/S50usbdevice
+++ b/external/rkscript/S50usbdevice
@@ -64,6 +64,7 @@ function_init()
    mkdir ${USB_FUNCTIONS_DIR}/mass_storage.0
    mkdir ${USB_FUNCTIONS_DIR}/uvc.gs6
    mkdir ${USB_FUNCTIONS_DIR}/hid.usb0
+   mkdir ${USB_FUNCTIONS_DIR}/hid.usb1
 }
 configfs_init()
@@ -342,11 +343,19 @@ bind_functions()
    test $RNDIS_EN = on && syslink_function rndis.gs0
    if [ $HID_EN = on ]; then
+       # Keyboard
        echo 1 > /sys/kernel/config/usb_gadget/rockchip/functions/hid.usb0/protocol
        echo 1 > /sys/kernel/config/usb_gadget/rockchip/functions/hid.usb0/subclass
        echo 8 > /sys/kernel/config/usb_gadget/rockchip/functions/hid.usb0/report_length
        echo -ne x05x01x09x06xa1x01x05x07x19xe0x29xe7x15x00x25x01x75x01x95x08x81x02x95x01x75x08x81x03x95x05x75x01x05x08x19x01x29x05x91x02x95x01x75x03x91x03x95x06x75x08x15x00x25x65x05x07x19x00x29x65x81x00xc0 > /sys/kernel/config/usb_gadget/rockchip/functions/hid.usb0/report_desc
        syslink_function hid.usb0
+       
+       # Mouse 
+       echo 2 > /sys/kernel/config/usb_gadget/rockchip/functions/hid.usb1/protocol
+       echo 1 > /sys/kernel/config/usb_gadget/rockchip/functions/hid.usb1/subclass
+       echo 3 > /sys/kernel/config/usb_gadget/rockchip/functions/hid.usb1/report_length
+       echo -ne x05x01x09x02xa1x01x09x01xa1x00x05x09x19x01x29x03x15x00x25x01x95x03x75x01x81x02x95x01x75x05x81x03x05x01x09x30x09x31x15x81x25x7fx75x08x95x02x81x06xc0xc0 > /sys/kernel/config/usb_gadget/rockchip/functions/hid.usb1/report_desc
+       syslink_function hid.usb1
    fi
    if [ $UMS_EN = on ];then

改完后需要刪除 buildroot/output/rockchip_rk3568，重新編譯。

驗證功能的話，直接改 buildroot/output/rockchip_rk3568/target/etc/init.d/S50usbdevice

buildroot/output/rockchip_rk3568/target/etc/init.d/.usb_config

usb_adb_en
usb_hid_en
usb_ums_en
ums_block=/dev/block/by-name/userdata
ums_block_auto_mount=on

./build.sh rootfs 燒錄即可看到

2. 測試功能

github倉庫：https://github.com/aagallag/hid_gadget_test

The HID Gadget driver provides emulation of USB Human Interface
Devices (HID). The basic HID handling is done in the kernel,
and HID reports can be sent/received through I/O on the
/dev/hidgX character devices.

復制hid_gadget_test.c 到sdk，執行

rk3568-sdk/prebuilts/gcc/linux-x86/aarch64/gcc-linaro-6.3.1-2017.05-x86_64_aarch64-linux-gnu/bin/aarch64-linux-gnu-gcc hid_gadget_test.c -o hid_gadget_test -static

生成 hid_gadget_test 使用adb push 到開發板

即可開始測試，輸入 g i s t r --left-shift 按下回車將發送數據

3. 開發板介紹

3.1 基本參數

3.2 實物圖

3.3 結構圖