Kernel version 3.12.30-AM335x-PD15.1.1 by PHYTEC. If I use the /sys/class/gpio way, I can see that the button input pin (gpio103 of AM3359) value changes from 0 to 1. Following the this exercise http://elinux.org/EBC_Exercise_11b_gpio_via_mmap and executing the below command for reading gpio pins usig /dev/me…
Tag: arm
Segmentation fault caused by strb w1, [x22,x23] when x23 reaches a certain value
Encountered an interesting segmentation fault on strb w1, [x22,x23] instruction in ARMv8 Assembly code when x23 reaches a certain value (which is 635), when I’m not using bl write function. However, if I use bl instruction to call write function, the segmentation fault does not occur; but the program fi…
How to run Linux on a QEMU ARM Versatile machine?
I’m trying to run linux on qemu, especially the versatile version. I downloaded qemu and linux from github. (qemu : https://github.com/qemu/qemu.git, linux : https://github.com/torvalds/linux.git) I think these two repositorys are the main project of them. Anyway, I compiled linux with 2 steps. make ARC…
Running qt creator via remote desktop
We are developing a software using QT creator. The software is meant to run on windows and on an ARM mini-computer running Debian. To test the software on the mini-computer, we logged in on the mini computer using ssh and an exported display. Some programs like Inkscape run fine, but we can’t get to run…
libelf corrupts ARM elf binaries
I’m trying to manipulate ARM elf binaries on linux using the libelf library without success. Even a minimal test-case corrupts my binaries, and I don’t know why. Here is my minimal test-code which reads an elf-file and then simply writes it back: If I run this code on a ELF 64-bit x86-64 executabl…
Specific reasons to use |= instead of =
I am currently looking over some code in the Linux kernel (thermal management). In some places there is a return value used to signal errors, which is set to 0 at the beginning of the function. Then when calling a function which may fail it is set to the new value using |= instead of =. Here is an example:
Build is happening by default with g++ instead of arm compiler?
I am encountering a very strange issue. I am building my source for ARM with ARM compilers. I modified CXX field in makefile to build using arm-linux-gnueabihf-g++ instead of g++ but while building its still taking g++. Can someone please help me here? MY makefile has the following entry I modified it to look…
How to understand the ARM registers dumped by kernel panic?
After Linux kernel oops on ARM platform, registers are dumped to console. But I got confused with analyzing these registers. For example, Questions: What does the 0xc0705970 stands for in SP: 0xc0705970:? Code address or data address? Where to find it? Why sp : c07059f0 is not at the beginning or end of SP re…
ARM: Disabling MMU and updating PC
In short, I would like to shut down all MMU (and cache) operations in a Linux context (from inside the Kernel), for debug purposes, just to run some tests. To be perfectly clear, I don’t intend that my system still be functional after that. About my setup: I’m currently fiddling with a Freescale V…
can’t get tslib to work with FT5x06
I have a arm based board with embedded linux on it and I believe it has a FT5x06 touch screen controller but seems like tslib has some problems with multitouch capacitive touch screen controllers. I cross compiled tslib with arm-linux-gcc4.5.1 and when after copying necessary files and setting necassary envir…