linux device drivers programming at kernel level

Recently read a lot of kernel programming and drive development tutorials, also refer to some of the Development Board examples. The conclusion is not as high as you can imagine. Developing a driver requires a certain understanding of the kernel, not a thorough interpretation. The drivers referred to below are for spe

Sys_select ()------> Do_select ()The final call to the file descriptor fd corresponds to the struct file type variable of the struct file_operations *f_op of the poll function.The function that poll points to returns information that is currently read and written.1) returns read and write information if it is currently readable or writable.2) If it is not currently read/write, block the process and wait for the driver to wake up, call the poll function again, or return the timeout.3, the driver

are larger than one page. They must occupy the physical page of the connection, because the device uses ISA or PCI system Bus data transfer, both of which use physical addresses DIY Assignment The Get_free_pages function can allocate up to a few m bytes of memory, but for a larger number of requests. Even requests that are far less than 128KB generally fail because the system memory is full of memory fragmentation

function defined. The kernel assigns an empty page to it.*/struct page * (*nopage) (struct vm_area_struct *vma, unsigned long address, int *type);/* Before the User space access page. The function agrees that the kernel will pre-load these pages into memory.*/Int (*populate) (struct vm_area_struct *vm, unsigned long address, unsigned long len, pgprot_t prot, unsigned long pgoff, I NT Nonblock);Memory-mappe

100% of the I/O threads in the user space are executed in a timely manner, even if the Linux kernel and real-time scheduling policies can be preemptible.Redesign for Linux driversWrite at least one simple Linux driver to handle the interrupt process at the kernel

the PCI system bus, both of which use physical addresses DIY Assignment The Get_free_pages function can allocate up to a few m bytes of memory, but for a larger number of requests, even requests that are much less than 128KB will typically fail because the system memory is full of memory fragmentation When the kernel cannot return the requested amount of memory or needs more than 128KB of memory, in addition to re

up Linux device driver Development related content: Armlinux working mode.SVC (Management) mode, USR mode;usr mode switches to svc mode. switching through software interrupts;When the code is running in USR mode, the software corresponds to the user space;When the code is running in SVC mode, the software runs in the kernel space. User space and

the operating system API, no longer give application software engineer directly interface.Then we have to ask, with the operating system, the driver becomes complex, then what does the operating system do?First, a complex software system needs to handle multiple concurrent tasks, without operating systems, and it is difficult to accomplish multitasking.Second, the operating system provides us with a memory management mechanism. A typical example is that, for most processors with MMU, Windows,

Learning device driver Programming also has a period of time, also wrote a few drivers, so there are some new understanding and understanding of the device driver, summed up. Learning device-driven programming has also been a whil

I have been learning device-driven programming for some time and have written several drivers. So I have a new understanding and understanding of the device driver. I have been learning device-driven programming for some time and

interaction module, he external to the operating system API, no longer give application software engineer directly interface.Then we have to ask, with the operating system, the driver becomes complex, then what does the operating system do?First, a complex software system needs to handle multiple concurrent tasks, without operating systems, and it is difficult to accomplish multitasking.Second, the operating system provides us with a memory management mechanism. A typical example is that, for m

Learning device driver Programming also has a period of time, also wrote a few drivers, so there are some new understanding and understanding of the device driver, summed up. Learning device driver Programming also has a period of

reached 66MHz or even 133MHz Equipped with a 32-bit data bus, and the specification already includes 64-bit extensions Platform independence as much as possible simplifies the task of adding and removing peripherals to the system PCI device is a jumper-free device that can be configured automatically during the boot phase PCI Addre

of Ethernet is mainly Ethernet II, Ethernet 802.3raw, Ethernet802.3sap, Ethernet802.3snapThe Ethernet controller implements the MAC layer function and must be used in conjunction with the PHY (physical layer transceiver), which is related to the OSI Data link layer, which implements the physical layer functionality. The MII (Media agnostic Interface) is a standard interface for connecting Fast Ethernet Mac and PHY, and the Ethernet device driver comm

The following is an article I recently read when I wrote a pci driver. I hope it will be helpful to you. Hi, I was a beginner in linux.The driver is also difficult, and many people are asked about it shamelessly. I would like to express my gratitude and sorry to these experts, especially unix1998. The level of helplessness is limited. It may be wrong in some places. IfIf you are not reading the original text smoothly, read the original text.Original a

1.1 In object-oriented programming, the device driver core layer and examples can define a base class for a class of similar things, and specific things can inherit the functions in this base class. If the implementation of a function of the inherited object is the same as that of the base class, it can directly inherit the functions of the base class. On the contrary, it can be overloaded. This object-orie

When writing drivers, it is generally necessary to add node information to the device tree, which provides a way to add device information directly to the drive.The drive template for I²c is as follows#include The SPI driver template is as follows#include The SPI and IIC drivers under

Compiling of Linux kernel modules and drivers-general Linux technology-Linux programming and kernel information. For details, refer to the following. The

Http://21cnbao.blog.51cto.com/109393/336263 1.1 Device Driver core layer and examples in the object-oriented programming, you can define a base class for a similar thing, specific things can inherit the functions in this base class. If the implementation of a function of the inherited object is the same as that of the base class, it can directly inherit the functions of the base class. On the contrary, it c

The compiling process of Linux kernel modules and drivers-general Linux technology-Linux programming and kernel information. The following is a detailed description. The