0. Overview

This project aims to port Linux OS to the HP Prime calculator. It is based on the Buildroot distribution. Long term goal is providing an alternative OS on Prime that is more capable than the original OS (PPL support, or better RPN support, native binary code execution for sure, and so on).

Please be aware this project is still in its early stages. It is not useful for general use as a calculator OS yet.

WARNING: THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

WARNING: The software is not fully tested. Installing it might brick your calculator (unable to boot) or you may lose the ability to install the original (stock) HP Prime OS back. Use it at your own risk.

WARNING: None of the software/ documentation/ guide provided shall be used for cheating in the exam. Linux OS shall not be used when using the calculator in the exam or any other cases that doing so would cause academic integrity violations.

If you have any questions, feel free to contact me (zephray at outlook dot com). All scripts are released to public domain (if applicable).

1. Status

Linux OS:

• [x] DDR initialization
• [x] U-boot Boot loader
• [x] Basic Linux OS
• [x] LCD controller SPI driver
• [x] LCD fbdev driver
• [x] PWM backlight driver
• [x] Touchscreen driver
• [x] PMIC driver
• [x] keypad driver
• [x] NAND flash driver
• [ ] Standby

Application:

• [ ] Launcher UI
• [ ] System settings UI

More applications T.B.D.

#安装编译依赖
sudo apt-get install cmake git libgtk2.0-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev
sudo apt-get install python-dev python-numpy libtbb2 libtbb-dev libjpeg-dev libpng-dev libtiff-dev libjasper-dev libdc1394-22-dev

#新版本 Ubuntu 的源中没有 libjasper-dev 手动添加源
sudo add-apt-repository "deb http://security.ubuntu.com/ubuntu xenial-security main"
sudo apt update
sudo apt install libjasper1 libjasper-dev

#创建编译目录：
mkdir opencv-build

#下载 OpenCV 源代码：
git clone https://github.com/Itseez/opencv.git

mkdir build
cd build

#创建 cmake 编译信息：
cmake -DENABLE_VFPV3=ON -DENABLE_VFPV4=ON -DENABLE_NEON=ON -DCMAKE_TOOLCHAIN_FILE=../opencv/platforms/linux/arm-gnueabi.toolchain.cmake ../opencv

#编译：
make -j4
make install

东西都在 ./install 目录下了。

编译自己的应用时注意 opencv2 头文件都是在 opencv4 文件夹下的。 编译参数：

OPENCV_INCLUDE=$(LIBPREFIX)/include/opencv4
-I$(OPENCV_INCLUDE)
-lopencv_core -lopencv_imgproc -lopencv_highgui -lopencv_ml -lopencv_video -lopencv_features2d -lopencv_calib3d -lopencv_objdetect -lopencv_flann

只是做一下记录。由于uboot的兼容性问题，仍然选用gcc5。以下主要记录命令，基本可以直接复制使用。因目标平台为Cortex-A7，选择gnueabihf工具链。全文基本复读https://ntzyz.io/post/arm-v7-a-cross-compile-notes，zyz真是太强啦！

环境：Ubuntu 16.04 LTS + bash 执行用户需要具有root权限

BusyBox本体：

#建立保存下载文件的临时文件夹
mkdir temp && cd temp

#下载linaro工具链
wget http://releases.linaro.org/components/toolchain/binaries/5.5-2017.10/arm-linux-gnueabihf/gcc-linaro-5.5.0-2017.10-x86_64_arm-linux-gnueabihf.tar.xz

#解压至/opt
xz -d gcc-linaro-5.5.0-2017.10-x86_64_arm-linux-gnueabihf.tar.xz
sudo tar xvf gcc-linaro-5.5.0-2017.10-x86_64_arm-linux-gnueabihf.tar -C /opt/

#准备目标文件系统，放置于/opt/basefiles中
sudo mkdir /opt/basefiles

#为当前session设置环境变量
export PATH=/opt/gcc-linaro-5.5.0-2017.10-x86_64_arm-linux-gnueabihf/bin:$PATH
export ARCH=arm
export CROSS_COMPILE=arm-linux-gnueabihf-

#下载并编译BusyBox
wget https://busybox.net/downloads/busybox-1.28.3.tar.bz2
tar xjvf busybox-1.28.3.tar.bz2
cd busybox-1.28.3
make defconfig
sudo ARCH=arm CROSS_COMPILE=/opt/gcc-linaro-5.5.0-2017.10-x86_64_arm-linux-gnueabihf/bin/arm-linux-gnueabihf- make -j4 install CONFIG_PREFIX=/opt/basefiles
cd ..

这次做了一些使用GD32单片机的制作。虽然说GD32是和STM32寄存器级兼容的，确实可以直接使用ST提供的工具和代码，但是这么做明显是违反了ST的协议的（当然使用CMSIS是不违反协议的）。一个方案是使用GD提供的工具和源码库，但是这样如果在未来想要迁移回ST的话则又是给自己找麻烦，所以干脆使用开源的解决方案libopencm3，就没有问题了。顺便调试方案也选择OpenOCD吧，不然用SEGGER的二进制总觉得不太清真。

本文就简单记录下过程，方便以后参考。环境：Arch Linux。

安装必要的依赖

从官方源安装以下包：

# pacman -S arm-none-eabi-gcc arm-none-eabi-newlib

从AUR安装以下包：

• openocd

创建一个项目

这里基本参考libopencm3提供的例子进行：

$ mkdir project
$ cd project
$ git init .
$ git submodule add https://github.com/libopencm3/libopencm3
$ make -C libopencm3 -j5
$ wget -O libopencm3.rules.mk https://raw.githubusercontent.com/libopencm3/libopencm3-examples/master/examples/rules.mk
$ wget -O libopencm3.target.mk https://raw.githubusercontent.com/libopencm3/libopencm3-examples/master/examples/stm32/l1/Makefile.include
$ cp libopencm3/lib/stm32/f1/stm32f103x8.ld .

修改libopencm3.target.mk的最后一行为：

include ../libopencm3.rules.mk

随后建立一个新的src文件夹，随便从libopencm3-examples里面复制个例子过来（.c和Makefile），如下修改Makefile文件：

OPENCM3_DIR = ../libopencm3
LDSCRIPT = ../stm32f103x8.ld

include ../libopencm3.target.mk

直接make hex或者make bin应该就能生成二进制了

使用OpenOCD下载

这里使用SWD方式下载，需要稍微编辑下配置文件

$ cd /usr/share/openocd/scripts/interface
$ cp jlink.cfg jlink-swd.cfg

在里面加入一行 transport select swd 即可。

随后启动OpenOCD并进行烧录：

openocd -f interface/jlink-swd.cfg -f target/stm32f1x.cfg
telnet localhost 4444
reset halt
flash write_image erase project.hex
reset