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authorGregory Fong <gregory.0xf0@gmail.com>2015-02-03 18:49:26 -0800
committerJonathan Corbet <corbet@lwn.net>2015-02-27 14:54:55 -0700
commitdce12391d70d24d428def2f5fc600a3b1f791ca6 (patch)
treeb2bf6217ace4b44017982185d0d294e1b78616d8 /Documentation/arm/Booting
parentc517d838eb7d07bbe9507871fab3931deccff539 (diff)
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: Gregory Fong <gregory.0xf0@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/arm/Booting')
-rw-r--r--Documentation/arm/Booting9
1 files changed, 7 insertions, 2 deletions
diff --git a/Documentation/arm/Booting b/Documentation/arm/Booting
index 371814a36719..83c1df2fc758 100644
--- a/Documentation/arm/Booting
+++ b/Documentation/arm/Booting
@@ -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
------------------