The learning of Linux device drivers is a huge project. Readers must first master the following basics.1. writing Linux device drivers requires engineers to have a good hardware foundation, understand the reading and writing metho
buffers help to separate the delivery and reception of data from the system call write and read, thereby improving the overall performance of the system
A good buffering mechanism requires interrupt-driven I/O
To properly interrupt-driven data transfer, the hardware should be able to generate interrupts according to the following semantics
For input, the device interrupts the processor when new data has arrived and the proc
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Linux Kernel Lecture Hall (1) cornerstone Driver Model for device drivers (6)
In the previous section, we roughly analyzed how driver_register works. Some details are not in p
Relationship between Linux device drivers and the entire hardware system 1. Device Classification and features the hardware of a computer system consists of CPU, memory, and peripherals. With the development of the IC (Integrated circuit) manufacturing process, the integration of chips is getting higher and higher, and
and the typical user-space malloc.(Simple heap-based memory allocation technology)The kernel uses special page-based allocation techniques to optimally utilize system RAM.Linux handles memory allocations by creating a series of memory object pools in which the size of the memory blocks in each pool is consistent. SecretariatWhen a request is assigned, a whole block is passed directly to the requestor in a pool that contains a sufficiently large chunk of memory.The kernel can allocate only a few
in the queue, and returns null if none. Do not delete this request after processing struct Sbull_dev *dev = Req->rq_disk->private_data ; if (! blk_fs_request (req)) {//Determine if a file system request is not a block device request PRINTK (kern_notice "Skip non-fs request.\ n "); end_request (req, 0); continue; } The//sbull_transfer () function is a real processing block device request function Sbull
contiguous and the corresponding data block on disk is also adjacent, then the general block layer can be merged with them, this way to produce a larger memory area is the physical segment.Common block Layer:1. The common block layer is a kernel component that handles requests from all block devices in the systemI\O Scheduler:1. Block device drivers can transmit one sector at a time, but the block i\o laye
encounter is part-time, and take her to the non-inflow of the guest house,It is advisable to first falsify the name, birthday and occupation information,So that JJ rounds can be disguised as lovers.Similarly, if the actual physical block device driver is to be implemented,It is probably not so random to return the physical structure of the device.For block device drive
Transferred from: http://blog.chinaunix.net/uid-15724196-id-128140.html2nd Chapter+---------------------------------------------------+| Write a block device driver |+---------------------------------------------------+| Zhao Lei || Email[email protected]|+---------------------------------------------------+| The copyright of the article belongs to the original author. || You are free to reprint this article, but the original copyright information mus
based on the Sbull program in the Linux device driver book to Linux Block device driver summary analysis.Start by understanding the core data structures in this block device:struct Sbull_dev {int size; /* Device Size in sectors */U8 *data; /* The data array */Short users; /*
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 kernel space:User space:Included software: application (softw
Porting real-time device drivers to embedded Linux-general Linux technology-Linux programming and kernel information. The following is a detailed description. Linux has occupied the embedded system market like a storm. According t
undefined macro. they are found in inux/capability. h and sched. h. in the two files. add # include in c
# Include
After the correction, make and press enter to display the output.
Make-C/lib/modules/2.6.22.1-41. fc7/build M =/home/hide1713/Desktop/kernel/examples/scull LDDINC =/home/hide1713/Desktop/kernel/examples/scull /.. /include modules
Make [1]: Entering directory '/usr/src/kernels/2.6.22.1-41. fc7-i686'
CC [M]/home/hide1713/Desktop/kernel/examples/scull/access. o
LD [M
This blog updates the latest developments in Linux device driver development (version 3rd) in real time.
At present, Chapter 4-9 has been initially completed on April 30, 2nd. Compared with version, these chapters are mainly changed.
[F] indicates correction or upgrade; [N] indicates new knowledge points; [D] indicates deleted content.Chapter 4
Assuming that the transfer data between the hardware and the driver management is delayed for some reason, the driver author should implement buffering
Data buffers help to separate the delivery and reception of data from the system call write and read, thereby improving the overall performance of the system
A good buffering mechanism requires interrupt-driven I/O
To properly interrupt-driven transmission data, the hardware should be able to generate interrupts acco
Linux Network DriverI would like to use this article to commemorate the past yearsI. PrefaceIn Linux, the network driver is also a big head, how to understand the network drive is as a Linux driver engineers must have the skills. But the same equipment, in different people's hands will have different effects, the reason is that the driver is good or not.Two.
Brief Introduction to interrupt handling for Linux Device Drivers
The first step related to interrupt handling in Linux device drivers is to apply for and release IRQ APIs: request_irq () and free_irq ().
The prototype of request_
: devices and drivers.
Devices includes all devices in the system that belong to the bus.
Drivers contains all drivers of the bus in the system.
Class: classifies devices in the system by function.
Devices: This Directory provides the device topology in the system.
Dev: View of the registered
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