docs: sh: convert new-machine.txt to ReST

:Author: Paul Mundt

.. toctree::

    :maxdepth: 1

    new-machine

Memory Management

=================

.. SPDX-License-Identifier: GPL-2.0

=============================

Adding a new board to LinuxSH

               ================================

=============================

               Paul Mundt <lethal@linux-sh.org>

companion chip type, and CPU type. Looking at a tree view of this directory

hierarchy looks like the following:

Board-specific code:

Board-specific code::

    .

    |-- arch

	    |

	    .. more boards here ...

Next, for companion chips:

Next, for companion chips::

    .

    `-- arch

	`-- sh

board-specific headers. Thus, include/asm-sh/hd64461 is home to all of the

hd64461-specific headers.

Finally, CPU family support is also abstracted:

Finally, CPU family support is also abstracted::

    .

    |-- arch

    |   `-- sh

explain this, we use some examples for adding an imaginary board. For

setup code, we're required at the very least to provide definitions for

get_system_type() and platform_setup(). For our imaginary board, this

might look something like:

might look something like::

    /*

    * arch/sh/boards/vapor/setup.c - Setup code for imaginary board

   vector.

   Note that these prototypes are generated automatically by setting

   __IO_PREFIX to something sensible. A typical example would be:

   __IO_PREFIX to something sensible. A typical example would be::

	#define __IO_PREFIX vapor

	#include <asm/io_generic.h>

   have a legacy io.h should remove it entirely and switch to the new model.

 - Add machine vector definitions to the board's setup.c. At a bare minimum,

   this must be defined as something like:

   this must be defined as something like::

	struct sh_machine_vector mv_vapor __initmv = {

		.mv_name = "vapor",

require the proper entry here and there in order to get things done.

The first thing to do is to add an entry to arch/sh/Kconfig, under the

"System type" menu:

"System type" menu::

    config SH_VAPOR

	    bool "Vapor"

machdir-y entry in order to be built. This entry needs to be the name of

the board directory as it appears in arch/sh/boards, even if it is in a

sub-directory (in which case, all parent directories below arch/sh/boards/

need to be listed). For our new board, this entry can look like:

need to be listed). For our new board, this entry can look like::

    machdir-$(CONFIG_SH_VAPOR)	+= vapor

list. The method for doing this is self explanatory, and so we won't waste

space restating it here. After this is done, you will be able to use

implicit checks for your board if you need this somewhere throughout the

common code, such as:

common code, such as::

	/* Make sure we're on the FooTech Vaporboard */

	if (!mach_is_vapor())

Looking at the 'make help' output, you should now see something like:

Architecture specific targets (sh):

  zImage                  - Compressed kernel image (arch/sh/boot/zImage)

  adx_defconfig           - Build for adx

  cqreek_defconfig        - Build for cqreek

  dreamcast_defconfig     - Build for dreamcast

  =======================   =============================================

  zImage                    Compressed kernel image (arch/sh/boot/zImage)

  adx_defconfig             Build for adx

  cqreek_defconfig          Build for cqreek

  dreamcast_defconfig       Build for dreamcast

  ...

  vapor_defconfig         - Build for vapor

  vapor_defconfig           Build for vapor

  =======================   =============================================

which then allows you to do:

which then allows you to do::

    $ make ARCH=sh CROSS_COMPILE=sh4-linux- vapor_defconfig vmlinux