Verison 1.0.3 Release

Based on Buildbotics 0.4.14

docs/cross_compile_rpi_kernel_module.md

@@ -0,0 +1,68 @@
+# Install the cross compiler
+
+    sudo apt-get update
+    sudo apt-get install -y gcc-arm-linux-gnueabihf
+
+# Determine the correct kernel version on the target pi
+
+    dpkg-query -l raspberrypi-kernel
+
+# Get the kernel source for the correct kernel version
+
+    wget https://github.com/raspberrypi/linux/archive/raspberrypi-kernel_1.20171029-1.tar.gz
+    tar xf raspberrypi-kernel_1.20171029-1.tar.gz
+    cd linux-raspberrypi-kernel_1.20171029-1
+
+# Prep the kernel source
+
+    KERNEL=kernel7
+    make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- bcm2709_defconfig
+    make -j 8 ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- modules_prepare
+
+# Create hello.c module
+
+    #include <linux/init.h>
+    #include <linux/module.h>
+
+    MODULE_LICENSE("GPL");
+
+    static int hello_init(void) {
+      printk(KERN_ALERT "Hello world!\n");
+      return 0;
+    }
+
+    static void hello_exit(void) {
+      printk(KERN_ALERT "Goodbye cruel world!\n");
+    }
+
+    module_init(hello_init);
+    module_exit(hello_exit);
+
+# Create a Makefile
+
+    CROSS := arm-linux-gnueabihf-
+    DIR:=$(shell dirname $(realpath $(lastword $(MAKEFILE_LIST))))
+    obj-m := hello.o
+
+    all:
+        $(MAKE) ARCH=arm CROSS_COMPILE=$(CROSS) -C kernel M=$(DIR) modules
+
+    clean:
+        $(MAKE) ARCH=arm CROSS_COMPILE=$(CROSS) -C kernel M=$(DIR) clean
+
+# Compile the module
+
+    ln -sf path/to/rpi-kernel kernel
+    make
+
+# Copy module to rpi
+
+    scp hello.ko pi.local:
+
+# Load it on the pi
+
+    sudo insmod hello.ko
+
+# Look for message in syslog
+
+    tail /var/log/syslog