Kernel initialisation parameters on ARM Linux--------------------------------------------- The following document describes the kernel initialisation parameterstructure, otherwise known as 'struct param_struct' which is usedfor most ARM Linux architectures. This structure is used to pass initialisation parameters from thekernel loader to the Linux kernel proper, and may be short livedthrough the kernel initialisation process.  As a general rule, itshould not be referenced outside of arch/arm/kernel/setup.c:setup_arch(). There are a lot of parameters listed in there, and they are describedbelow:  page_size    This parameter must be set to the page size of the machine, and   will be checked by the kernel.  nr_pages    This is the total number of pages of memory in the system.  If   the memory is banked, then this should contain the total number   of pages in the system.    If the system contains separate VRAM, this value should not   include this information.  ramdisk_size    This is now obsolete, and should not be used.  flags    Various kernel flags, including:    bit 0 - 1 = mount root read only    bit 1 - unused    bit 2 - 0 = load ramdisk    bit 3 - 0 = prompt for ramdisk  rootdev    major/minor number pair of device to mount as the root filesystem.  video_num_cols video_num_rows    These two together describe the character size of the dummy console,   or VGA console character size.  They should not be used for any other   purpose.    It's generally a good idea to set these to be either standard VGA, or   the equivalent character size of your fbcon display.  This then allows   all the bootup messages to be displayed correctly.  video_x video_y    This describes the character position of cursor on VGA console, and   is otherwise unused. (should not be used for other console types, and   should not be used for other purposes).  memc_control_reg    MEMC chip control register for Acorn Archimedes and Acorn A5000   based machines.  May be used differently by different architectures.  sounddefault    Default sound setting on Acorn machines.  May be used differently by   different architectures.  adfsdrives    Number of ADFS/MFM disks.  May be used differently by different   architectures.  bytes_per_char_h bytes_per_char_v    These are now obsolete, and should not be used.  pages_in_bank[4]    Number of pages in each bank of the systems memory (used for RiscPC).   This is intended to be used on systems where the physical memory   is non-contiguous from the processors point of view.  pages_in_vram    Number of pages in VRAM (used on Acorn RiscPC).  This value may also   be used by loaders if the size of the video RAM can't be obtained   from the hardware.  initrd_start initrd_size    This describes the kernel virtual start address and size of the   initial ramdisk.  rd_start    Start address in sectors of the ramdisk image on a floppy disk.  system_rev    system revision number.  system_serial_low system_serial_high    system 64-bit serial number  mem_fclk_21285    The speed of the external oscillator to the 21285 (footbridge),   which control's the speed of the memory bus, timer & serial port.   Depending upon the speed of the cpu its value can be between   0-66 MHz. If no params are passed or a value of zero is passed,   then a value of 50 Mhz is the default on 21285 architectures.  paths[8][128]    These are now obsolete, and should not be used.  commandline    Kernel command line parameters.  Details can be found elsewhere.