Embedded Systems on ankit_kdev

Understanding Forward Declarations in C

Sun, 17 May 2026 17:00:31 +0530

One of the best ways to learn systems programming is by reading real-world code. Recently, while reading the Linux kernel source, I noticed something interesting inside drivers/pinctrl/core.h:

#include <linux/kref.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/radix-tree.h>
#include <linux/types.h>

#include <linux/pinctrl/machine.h>

struct dentry;
struct device;
struct device_node;
struct module;

At first glance, these lines seem incomplete. We see declarations like struct device; but no actual definition. Where is the complete structure with all its members? Why didn’t file defining this structure isn’t included?

Configure U-boot For Beaglebone Black

Wed, 22 Apr 2026 15:02:44 +0530

Overview

U-Boot (Universal Boot Loader) is the go-to bootloader for embedded Linux systems. If you’re working with the BeagleBone Black (BBB), building U-Boot from source gives you full control over the boot process, from initializing hardware to loading your kernel. This guide walks you through cross-compiling and installing U-Boot on the BBB from scratch.

This blog will explain how to compile and install U-Boot, and then either manually boot from the U-Boot prompt or use uEnv.txt to autoboot the kernel. You can also use extlinux/extlinux.conf to boot the kernel.

Build and Install Linux Kernel For Beaglebone Black

Wed, 08 Apr 2026 22:31:16 +0530

Overview

The BeagleBone Black (BBB) uses an ARM Cortex-A8 32 bit processor, so the kernel must be cross-compiled on an x86 machine and then deployed to the board. This blog will assume that you already have a os[debian/ubuntu] installed on your sd card.

We’ll:

set up toolchain
fetch kernel source
configure for BBB
build kernel + modules
deploy to SD card / board

1. Prerequisites

Make sure you have:

Ubuntu (or any Linux host)
Cross compiler for ARM (arm)

Install required tools: