The use of Unix in embedded computer systems such as networking equipment, mobile phones, media players, set-top boxes, etc.

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17
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3answers
206 views

Can I achieve functionality similar to interrupts in Linux userspace?

One of functionalities I miss the most from "small embedded" in Embedded Linux is the interrupts. A signal appears on a specific pin, or other interrupt source is triggered and whatever was done ...
13
votes
4answers
469 views

Corruption-proof SD card filesystem for embedded Linux?

Recently we had a rather unpleasant situation with our customer - Raspberry Pi based "kiosk" used to display remote sensing data (nothing more fancy than a kiosk mode browser displaying a ...
3
votes
1answer
896 views

Which TCP congestion control algorithm is best for low speed radio modems?

On my project we have remote Linux nodes that communicate over the Internet via very low speed CDMA cell modems. The bandwidth on these modems is about 2kbyte/second and the RTT back to the server is ...
3
votes
1answer
115 views

Why doesn't 'ar' work like the manpage says?

I'm trying to use 'ar' included in Debian Wheezy armel version of binutils and it doesn't seem to operate like on other systems I've encountered. Some sample output from the command-line: $ ar ...
3
votes
1answer
313 views

Booting using initramfs instead of uramdisk

I am working on Zynq Microzed board. It is booting perfectly with uramdisk.image.gz but I trying to boot it with initramfs.cpio. In this regard I have made following changes in header files of ...
2
votes
1answer
126 views

Most reliable way to check for connected client?

I have an embedded Linux OS developed from scratch using Yocto. This talks to a Windows XP/7 client. The embedded OS runs a DHCP server and gives an address to the client. The problem is that the ...
0
votes
0answers
64 views

How can I make a configuration web page for a linux appliances? Any pre made solutions available?

I am putting together a bunch of embeded linux appliances that we will be installing at a few locations. Built the whole thing from scratch using Raspbian (debian based) and Raspberry Pis. There are ...
1
vote
0answers
60 views

Removed USB storage device is still mounted

I'm working on a embedded linux system based on busybox. Sometimes a USB device which is physically removed from the post is still displayed in mount, df or /proc/mounts. If I reattach the device, it ...
1
vote
1answer
126 views

How to get log from u-boot without com-port

U-boot is configured to print its logs into com-port by default. There is a device I can't receive this information (without uart/com). Can I configure u-boot to store its log strings into some place ...
1
vote
1answer
326 views

Conntrack TCP Timeout for state stablished not working

Im using a private IP address and I want to keep alive SNAT entries in my Router (Gateway) for at least two hours (some windows apps of my network are using TCP keepalive set to 2 hours). Gateway is a ...
0
votes
0answers
198 views

using sf probe to make u-boot faster

My uboot was running slow on a ARM cortex A9 processor based Xilinx zynq chip. Xilinx forum referred me to the following to solve this issue: +From 0a212cfc2dd4e4d1595de2ca2dde3f642e5707e7 Mon ...
0
votes
1answer
165 views

How can I boot with a compressed rootfs?

My problem is: I cannot use compressed rootfs (the kernel crashes during boot) but uncompressed ones work fine. What I did: I'm using Buildroot 2013.11 to generate Images for my embedded Linux ...
1
vote
2answers
154 views

Could not mount UBIFS on SD card

I guess this is not a big problem, still I can't see what's the matter. I'm building Images for an Embedded Linux (2.6.39) ARM9 System with Buildroot 2013.11, which is booting from an SD card. I was ...
4
votes
1answer
143 views

What does this dd command do exactly?

I have the an embedded device with this SD card: [root@(none) ~]# busybox fdisk -l Disk /dev/mmcblk0: 3965 MB, 3965190144 bytes 4 heads, 16 sectors/track, 121008 cylinders Units = cylinders of 64 * ...
1
vote
1answer
81 views

WARNING: at kernel/irq/handle.c - after changing rootfs, but why?

today I changed from an image with initramfs to an image with separate kernel and rootfs. Theses images are used for an Embedded System (ARM9 SAM9G25), that is runnging with an Linux 2.6.39. During ...
0
votes
2answers
86 views

GPIO User Space App

GPIO User Space App describes user space application to test the GPIO. Another related link is Linux GPIO Driver. This would be running on a xilinx zynq board having an ARM Cortex A 9 processor. I ...
1
vote
0answers
224 views

How to cross compile linux kernel for ARM using GNU ARM toolchain? [closed]

I'm trying to cross compile latest Linux kernel 3.14 for ARM architecture. When I executed - make ARCH=arm CROSS_COMPILE=/usr/bin/arm-linux-gnueabi- The terminal gave me an error that: make: *** ...
1
vote
1answer
56 views

Uninstall Linux on an embedded board

I am using an embedded board, a FOX G20 V with an ATMEL AT91SAM9G20 processor. I would like to know first of all, which specific linux version I am using on this board, but also, how to remove it. ...
1
vote
0answers
140 views

Replacing default initramfs with my own

I followed this article to develop my own sample intramfs.cpio Now I have to put this in my kernel and compile. The procedure that I follw for petlinux is that I first run petalinux-config (and ...
0
votes
0answers
316 views

No filesystem could mount root, tried: jffs2

CPU: ARM Cortex A-9 This is the kernel command line that I appears in configuration menu root=mtd:jffs2 rw rootfstype=jffs2 console=ttyps0,115200 I have put three files in flash: BOOT.BIN in mtd0 ...
3
votes
1answer
591 views

While trying to open /dev/mtd2 for read/write access: Permission denied

Looks like my MTD2,and MTD3 partitions are write protected. The OS is booting from SD card on a ARM Cortex A 9 processor. root@Xilinx-ZC702-2013_3:~# mount /dev/mmcblk0p1 /mnt/ ...
0
votes
1answer
729 views

Debian and Systemd: breaking ordering cycle error

I'm a new embedded developer I'm trying to make systemd 37 work with freescale vybrid board (A5 and M4) running on linux-3.0 After boot with some breaking ordering cycle error, I check with ps ...
1
vote
0answers
92 views

tty not resizing properly

I'm running an embedded poky linux (linux-yocto v3.13) on a beagleboard. However, I'm having trouble when logging in over a serial using PuTTY: the terminal does not resize at all. Usually, the ...
1
vote
0answers
87 views

Interfacing ds1337 RTC on LPC17xx

I am a newbie and I am trying to understand how to interface DS1337(RTC) on LPC17xx Board. This board uses uclinux 2.6.33. .CONFIG: CONFIG_RTC_LIB=y CONFIG_RTC_CLASS=y CONFIG_RTC_HCTOSYS=y ...
1
vote
0answers
150 views

Arch Linux iMX6 capacitive touch LCD panel

I want to create an embedded system with a 7 inch capacitive touch screen and am planning on using Arch Linux on a Varscite made Freescale iMX6 quad based SOM development kit for this purpose. What I ...
2
votes
1answer
78 views

What are the two values in < > in a device tree .dts file ?

Following is the code snippet in a device tree file: flash@0 { compatible = "n25q128"; reg = <0x0>; spi-max-frequency = <50000000>; ...
4
votes
2answers
253 views

File system that never breaks (data loss acceptable)

There're several existing topics revolving around this issue, but what I seek is slightly different. I have an sd card on an embedded Linux and it suffers from power loss. I might be able to modify ...
1
vote
0answers
86 views

Why is my embedded Linux unable to detect the sd device?

I have this ARM9 SAM9G25 embedded System, running a Linux 2.6.39 Kernel and a Busybox. I put the Images (of the bootloaders, and the linux+initramfs) on a SD so that in the end the system is booting ...
3
votes
1answer
69 views

How to determine how many bytes / hr are being written to my SD card

I have a Debian embedded Linux system that uses an SD card as the RFS. What is a reliable way to determine how many bytes / hr are being written to the SD card?
5
votes
1answer
276 views

How to set the CPU freq. in Linux?

I'm using this ARM9 SAM9G25 embedded system, that when switched on, is only online for a few seconds and because I want to speed up the whole process, I'd like to check the CPU frequency, and set it ...
0
votes
1answer
122 views

supported 2014 distro with 2.6.x kernel

I'm cutting my teeth at putting together a Linux install for a PC104 board that supports <= kernel 2.6.x with a Disk-On-Chip. I've read up on Embedded.org and Yocto, but before I try compiling ...
1
vote
1answer
36 views

Embedded Linux Power Failure Issues

Many routers run a Linux OS and abrupt power failure can happen. Considering this - how do they handle the possibility of file system corruption caused by a power failure? If they make the system read ...
1
vote
1answer
333 views

High RX packet error count with modem - how to analyze?

I'm testing a CDMA modem on my Debian embedded Linux system. I'm doing some wgets of large files and am seeing the connection drop now and then. Looking at the ifconfig output for the PPP interface ...
2
votes
1answer
53 views

catch http requests from another process

Suppose a process, among other things, is posting https requests, for example with curl. Assuming I have root privileges, is there a way to intercept such requests and respond with an http error ...
0
votes
1answer
542 views

How to change hard disk spin-down time on my WD MyBook Live?

I have a 2TB Western Digital MyBook Live. It works quite well and provides a web-based administration interface. There is an option to either enable or disable power saving mode, which spins down the ...
1
vote
1answer
78 views

flash_erase & nandwrite seem to work, but uname -a shows the same kernel version

I've seen this question: How can I flash_erase mtd0? I have a similar problem with my mini2440. When I use flash_erase /dev/mtd2 0 0 and then nandwrite -p -N /dev/mtd2 uImage-mini2440 ...
1
vote
3answers
317 views

Why does boot from SD card with my custom kernel result in “VFS: Cannot open root device”?

I'm using an embedded board ARM9 SAM9G25. I want to boot from SD card. When I build a linux kernel with a built-in rootfs (initramfs) then it boots. I want to separate the kernel from rootfs and I ...
1
vote
1answer
341 views

Basic script in Angstrom Linux running on a Beaglebone Black

On my embedded system, I can toggle a user led with: echo > 1 sys/class/leds/beaglebone:green:usr2/value. Similarly, I can find the value of a GPIO (gpio60) (set to input), with more ...
0
votes
1answer
140 views

Having difficulties mounting a rootfs for an embedded Linux

I want my Kernel to start a squashfs rootfs for an embedded Linux. The squashfs file is on a sdcard, therefor i put these parameters on it's command line: console=ttyS0,115200 root=/dev/sdb1 rw ...
3
votes
1answer
2k views

How to extract files from uImage?

Buildroot is generating Images for an embedded device where they should run on. This is working very well. In those Images the rootfs is included. Due to some research I'd like to look into that ...
2
votes
2answers
674 views

Setup ntp client with embedded device

I need to run an NTP client on a very limited embedded device. ntpd is available but I do not see anything like rc.conf, or ntp.conf, or xntp.conf? Can someone advise on how to setup NTP? I ran ...
3
votes
1answer
84 views

Embedded Linux: Which machine directory to pick in /arch/arm?

I am just starting out with embedded Android drivers, so any help would be great. I haven't found a lot of resources online. At the moment, I am working through a tutorial on porting a driver, and ...
0
votes
3answers
67 views

How can I add a script to embedded Linux

I have a script (let's say Hello World), that I want to include to my embedded Linux. I'm using Buildroot and want to start the script in Busybox. But because I'm cross-compiling for the target I'm ...
0
votes
1answer
144 views

Change the root filesystem on an embedded system

I'm using Buildroot to generate an embedded Linux with a kernel v. 2.6.39, which in the end starts busybox. Everything works fine when building with Initramfs as "rootfs". But Initramfs isn't the best ...
2
votes
1answer
1k views

upgrade Python to 2.7.2

I have an embedded system running on Python 2.6.5 and i want it to upgrade to 2.7.2 (I have a running system with different kernel that runs 2.7.2). I have copied the binary but then it told me: ...
2
votes
1answer
577 views

Transparent Ethernet over GRE not forwarding traffic

I am running on Linux 2.6.30.9 and have been trying to setup a transparent ethernet over GRE tunnel. The network topology used is as follows: I want to bridge PC1 and PC2 using Transparent Ethernet ...
2
votes
1answer
167 views

How to build a basic embedded linux on a Qualcomm router?

Not knowing the first thing on how to build a minimal linux system on an embedded device, I'd like to get some pointers in the right direction. Generally speaking, I'd like to know what are the ...
1
vote
1answer
166 views

How to make a USB storage device undetectable in u-boot?

I need to do a test in an embedded system where I plug in the USB storage device and do "usb start" but the USB storage device is not detected. I have a working pendrive. How to make it undetectable ...
1
vote
0answers
163 views

Log files corrupted with NUL characters and text from other processes

I am running Wind River Linux 4.3 on an embedded Freescale single board computer (SBC). Output from uname -a: Linux ge101 2.6.34.10-myname-grsec-WR4.3.0.0_cgl #1 SMP PREEMPT Mon Aug 26 01:35:35 PDT ...
0
votes
2answers
604 views

GRE supported in kernel but iproute2 cant create GRE tunnel

Im trying to create IP over GRE tunnel but i get No such device: ip tunnel add gre0 mode gre remote 192.168.152.22 local 192.168.152.21 ttl 255 ioctl: No such device I have compiled GRE support in ...