embedded-linux

问题 I am running Linux kernel 3.3 on Xilinx's Microblaze with full MMU. the task that I am doing requires me to know the following: I need to create a text file (buffer) and locate the physical address of this buffer and I don't want the kernel to write this file into discontinuous regions of memory. the reason I need this because I have a DMA engine that streams data from a preset physical memory address, so I need to force Linux to create the buffer file at that exact memory location, so that

问题 In Yocto-based Embedded Linux distributions, I am really interested in finding the complete list of packages/recipes/kernel modules from each dependent layers that will be built and installed to an image file before executing the image building recipe such as: bitbake my-image-minimal Is there a way to achieve this? Any guidance in this regard is appreciated. Thanks in advance. 回答1: Yes, like this On old Bitbake versions: bitbake -g <image> && cat pn-depends.dot | grep -v -e '-native' \ |

问题 I have just made my first driver module, the hello world module following LDD3. However unfortunately encountered this error: insmod: error inserting './hello.ko': -1 Invalid module format. I am doing this on Ubuntu 11.04, and my environment: $ uname -r 2.6.38-8-generic I get the kernel source like this: sudo apt-cache search linux-source linux-source - Linux kernel source with Ubuntu patches linux-source-2.6.38 - Linux kernel source for version 2.6.38 with Ubuntu patches $sudo apt-get

问题 What are irq domains, i read kernel documentation (https://www.kernel.org/doc/Documentation/IRQ-domain.txt) they say: The number of interrupt controllers registered as unique irqchips show a rising tendency: for example subdrivers of different kinds such as GPIO controllers avoid reimplementing identical callback mechanisms as the IRQ core system by modeling their interrupt handlers as irqchips, i.e. in effect cascading interrupt controllers. How GPIO controller can be called as interrupt

问题 I have successfully compiled Linux kernel for android: root@ubuntu:~/common# ARCH=arm CROSS_COMPILE=~/mydroid/prebuilt/linux-x86/toolchain/arm-eabi-4.4.0/bin/arm-eabi- make CHK include/linux/version.h make[1]: `include/asm-arm/mach-types.h' is up to date. CHK include/linux/utsrelease.h . . . SYMLINK include/asm -> include/asm-arm CALL scripts/checksyscalls.sh <stdin>:1097:2: warning: #warning syscall fadvise64 not implemented <stdin>:1265:2: warning: #warning syscall migrate_pages not

问题 This question already has an answer here : Cross-compiling mono for proprietary ARM device (1 answer) Closed 5 years ago . For the last three days I've been trying to cross-compile Mono 2.11.4 for the TechNexion Blizzard board (running an unknown version of Angstrom) using a virtual Ubuntu (12.04) on my Win7 32 bit machine and CodeSourcery Sourcery G++ ARM toolchain, but with little/no success. I've followed every tutorial on the web but it just doesn't work. CodeSourcery Sourcery G++

问题 This question already has an answer here : Cross-compiling mono for proprietary ARM device (1 answer) Closed 5 years ago . For the last three days I've been trying to cross-compile Mono 2.11.4 for the TechNexion Blizzard board (running an unknown version of Angstrom) using a virtual Ubuntu (12.04) on my Win7 32 bit machine and CodeSourcery Sourcery G++ ARM toolchain, but with little/no success. I've followed every tutorial on the web but it just doesn't work. CodeSourcery Sourcery G++

问题 I am looking to write a PWM driver. I know that there are two ways we can control a hardware driver: User space driver. Kernel space driver If in general (do not consider a PWM driver case) we have to make a decision whether to go for user space or kernel space driver. Then what factors we have to take into consideration apart from these? User space driver can directly mmap() /dev/mem memory to their virtual address space and need no context switching. Userspace driver cannot have interrupt

问题 While building the kernel I am giving LOADADDR as "0x80008000": make uImage LOADADDR=0x80008000 Can you please help to understand what is the use of this? Can I change the LOADADDR, is there any restriction on the length of the LOADADDR? 回答1: (I'm assuming that you're using ARM based on the mention of U-Boot and the value of LOADADDR.) Can you please help to understand what is the use of this? LOADADDR specifies the address where the kernel image will be located by the linker. (This is true

问题 On my x86_64 board, there is i2c-bus coming out of a MFD device. There are devices on to this i2c-bus. I am able to detect these devices using i2cdetect program. # i2cdetect -y 0 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- 4c -- -- -- 50: -- -- -- -- -- -- -- 57 -- -- -