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Author Archives: spatlou

About spatlou

Emblogic is a technology design, integration and devices Realization Company, providing out of the box solutions and end to end embedded solutions for product development and deployment. We offers professional design services like hardware and software development, customizable product designs, Systems Engineering and COTS Solutions that improve quality and accelerate time-to-market for a broad range of embedded systems. Through technological innovations, quality and timely deliveries, we work to ensure increased values and optimized throughput for our customers. Our solutions ensure customers sustain their competitive edge and added value and volumes to their business. We aspire to serve the industry through training, development and consulting.

Character Device Driver – Capabilities. Restricted Permissions

Access to a device is controlled by the permissions on the device file(s), and the driver is not normally involved in permissions checking. There are situations, however, where any user is granted read/write permission on the device, but some control … Continue reading

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Character Device Driver – Blocking IO using wait queues

How does a driver respond if it cannot immediately satisfy the request? A call to read may come when no data is available, but more is expected in the future. Or a process could attempt to write, but your device … Continue reading

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Atomic Variables in Device Drivers

Sometimes, a shared resource is a simple integer value. Suppose your driver maintains a shared variable shrd that tells how many device operations are currently outstanding. Normally, even a simple operation such as: sgrd++; would require locking. Some processors might … Continue reading

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Log file for nested structures

RCS file: dist_add.c,v Working file: dist_add.c head: 1.4 branch: locks: strict access list: symbolic names: keyword substitution: kv total revisions: 4; selected revisions: 4 description: This is the base file for adding distances using structures. —————————- revision 1.4 date: 2013/12/12 … Continue reading

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PC16550D UART with FIFO

The PC16550D is an improved version of he original 16450 USRT functionally identical to 16450 on powerup (Character Mode). The PC16550D can be put into an alternative mode, (FIFO mode) to relieve the CPU of  excessive software overhead.

Posted in Serial Port Driver | 1 Comment

Project 04: Client-Server using Threads and Sockets

Threads are “light weight processes” (LWPs). The process has five fundamental parts: code (“text”), data (VM), stack, file I/O, and signal tables. “Heavy-weight processes” (HWPs) have a significant amount of overhead when switching: all the tables have to be flushed … Continue reading

Posted in Project 04: FTP based Client Server using Threads and Sockets | 15 Comments

Project 05: Character Device Driver

Makefile for a basic kernel module

obj-m += hello-1.o

make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules

make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean Continue reading

Posted in Character Driver | Tagged , , , , , | 14 Comments

Writing device drivers in Linux

Pre-requisites In order to develop Linux device drivers, it is necessary to have an understanding of the following: C programming. Some in-depth knowledge of C programming is needed, like pointer usage, bit manipulating functions, etc. Microprocessor programming. It is necessary … Continue reading

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What is Device Drivers

People new to Linux often hear that it has excellent support for all kinds of cards and that the device drivers are stable and fast. Sometimes, though, setting up devices under Linux is often not all plug-and-play. Everything is a … Continue reading

Posted in Device Drivers | Tagged , , | 1 Comment

What is Embedded Linux

Over the last decade, a sea change has occurred in the world of embedded systems, driven by the appearance of sophisticated new products such as PDAs and cell phones and by the continual increase in the amount of resources that … Continue reading

Posted in Embedded Linux | Tagged , , | 1 Comment


All of you are requested to “add category” to your posts. Thank You

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Pseudo driver 2.4 kernel

Starting to write Pseudo Driver using 2.4 kernel ? Any doughts Please let me know


Client Server using fifo

Please give the updates

Posted in Uncategorized | 3 Comments

Client Server using Pipes

Any updates for client server application using pipes

Posted in Uncategorized | 13 Comments