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Commit dce12391 authored by Gregory Fong's avatar Gregory Fong Committed by Jonathan Corbet
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Documentation: arm: Update for DT-only platforms 



The documentation specified that a machine type is mandatory and made
that assumption in a few places.  However, for DT-only platforms, the
current advice is that no machine type should be registered, so update
accordingly.

Signed-off-by: default avatarGregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent c517d838

Documentation/arm/Booting

+7 −2
Original line number Diff line number Diff line
@@ -58,13 +58,18 @@ serial format options as described in 
--------------------------



Existing boot loaders:		OPTIONAL

New boot loaders:		MANDATORY

New boot loaders:		MANDATORY except for DT-only platforms



The boot loader should detect the machine type its running on by some

method.  Whether this is a hard coded value or some algorithm that

looks at the connected hardware is beyond the scope of this document.

The boot loader must ultimately be able to provide a MACH_TYPE_xxx

value to the kernel. (see linux/arch/arm/tools/mach-types).

value to the kernel. (see linux/arch/arm/tools/mach-types).  This

should be passed to the kernel in register r1.



For DT-only platforms, the machine type will be determined by device

tree.  set the machine type to all ones (~0).  This is not strictly

necessary, but assures that it will not match any existing types.



4. Setup boot data

------------------

Documentation/arm/README

+11 −4
Original line number Diff line number Diff line
@@ -185,13 +185,20 @@ Kernel entry (head.S) 
  board devices are used, or the device is setup, and provides that

  machine specific "personality."



  This fine-grained machine specific selection is controlled by the machine

  type ID, which acts both as a run-time and a compile-time code selection

  method.

  For platforms that support device tree (DT), the machine selection is

  controlled at runtime by passing the device tree blob to the kernel.  At

  compile-time, support for the machine type must be selected.  This allows for

  a single multiplatform kernel build to be used for several machine types.



  You can register a new machine via the web site at:

  For platforms that do not use device tree, this machine selection is

  controlled by the machine type ID, which acts both as a run-time and a

  compile-time code selection method.  You can register a new machine via the

  web site at:



    <http://www.arm.linux.org.uk/developer/machines/>



  Note: Please do not register a machine type for DT-only platforms.  If your

  platform is DT-only, you do not need a registered machine type.



---

Russell King (15/03/2004)