petalinux预留内存

最近在开发过程中，希望能保留一段内存不被系统使用，这样这段内存里面的数据就不会被系统程序修改。我使用的是xilinx zynqMP Soc系列的开发板，按照xilinx wiki 预留内存教程试了下。

步骤

1. 使用petalinux创建一个project

2. 修改设备树文件system-user.dtsi, 添加预留内存的设备树节点
   (project-spec/meta-user/recipes-bsp/device-tree/files/system-user.dtsi)

3. petalinux-build

适用于 64-bit Cortex-A53 MPSoC的节点信息

reserved-memory {
   #address-cells = <2>;
   #size-cells = <2>;
   ranges;
 
   reserved: buffer@0 {
      no-map;
      reg = <0x0 0x40000000 0x0 0x10000000>;
   };
};
 
reserved-driver@0 {
   compatible = "xlnx,reserved-memory";
   memory-region = <&reserved>;
};

适用于32-bit Cortex-A9 Zynq的节点信息

reserved-memory {
   #address-cells = <1>;
   #size-cells = <1>;
   ranges;
  
   reserved: buffer@0x38000000 {
      no-map;
      reg = <0x38000000 0x08000000>;
   };
};
  
reserved-driver@0 {
   compatible = "xlnx,reserved-memory";
   memory-region = <&reserved>;
};