Web5 okt. 2024 · IOCTL is referred to as Input and Output Control, which is used to talk to device drivers. This system call is available in most driver categories. The major use of … Web21 jul. 2014 · a GET_FOO ioctl would be _IOR, although the kernel would actually write data to user space. The first argument to _IO, _IOW, _IOR, or _IOWR is an identifying letter or number from the table below. Because of the large number of drivers,many drivers share a partial letter with other drivers.
Documentation/ioctl/ioctl-number.txt_zjgsu_linux的博客-CSDN博客
Web本文已参与「新人创作礼」活动,一起开启掘金创作之路。 如何创建一个字符设备以及open、close、write、read等函数的使用以及file_operations结构体注释请看Linux驱动之创建字符驱动——学习笔记(3)。. 这篇文章单独说明一下ioctl的配置及使用。 WebDecoding an IOCTL Magic Number — The Linux Kernel documentation Decoding an IOCTL Magic Number ¶ To decode a hex IOCTL code: Most architectures use this generic format, but check include/ARCH/ioctl.h for specifics, e.g. powerpc uses 3 bits to encode read/write and 13 bits for size. inz 1178 application form
Linux Kernel Documentation :: ioctl : ioctl-number.txt - mjmwired
Web21 sep. 2024 · 设备类型 序列号 方向 数据尺寸 8位 8位 2位 13/14位 1、设备类型字段(8位) 命令码的设备类型字段为一个“幻数”,可以是0 ~ 0xff的值,内核中的ioctl-number.txt给 … Web5 aug. 2024 · ioctl-number.txt文件记录了内核中已经使用的ioctl命令,我们在构建自己的ioctl命令时尽量不要和内核已经使用的命令冲突; (1)Code:命令中的设备类型字段; (2)Seq:命令中的序列号字段; (3)Include File:这些命令被哪个文件占用; (4)Comments:命令的说明,比如conflict就说明这个命令和其他的文件的定义冲突了; … WebAn ioctl call has two parameters in addition to the file descriptor that the ioctl acts on: the ioctl number cmd, and an argument arg. The argument can be an immediate value or a pointer to a buffer. Here, if the driver writer is following the convention, arg should be a pointer to a 24-byte buffer in the application memory space. on screen image