I want to pass a custom parameter to the kernel at boot time, which my new code will use. This parameter is a number.
I know how to pass value to kernel module using ker
If you know how to pass a value to a kernel module, you know enough :)
insmod my_module param=value
If your module is built-in in the kernel, you can add your parameter to the kernel parameters
vmlinux ... my_module.param=value ...
Here a reference: kernel-parameters.txt