EDK2 Overview

最近在移BL到UEFI, 来大概看下基础。UEFI(Unified Extensible Firmware Interface)是Intel提出的一种规范(specification),由PC BIOS而来,如下图(阿桑的wikipedia打不开?画个txt pic),介于OS和FW之间,QCOM Android BL似乎用它来代替LK。UEFI is based on ...阅读全文

devfreq governor代码分析

参考内核5.x,代码路径是在drivers/devfreq/,devfreq的代码定义是:Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework for Non-CPU Devices。而CPU动态调频是drivers/cpufreq,devfreq是基于cpufreq而来。第一次引入这个特性描述: ...阅读全文

How to build mkfs.erofs for ARM64

mkfs.erofs is a user-space tool to create erofs filesystem images.erofs是华为为了增强安卓性能提出的自研文件系统,其内核文档提到用户态工具:The following git tree provides the file system user-spacetools under development ...阅读全文