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 <[email protected]>
---
Documentation/arm/Booting | 9 +++++++--
Documentation/arm/README | 15 +++++++++++----
2 files changed, 18 insertions(+), 6 deletions(-)
diff --git a/Documentation/arm/Booting b/Documentation/arm/Booting
index 371814a..83c1df2 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
------------------
diff --git a/Documentation/arm/README b/Documentation/arm/README
index aea3409..9d1e5b2 100644
--- a/Documentation/arm/README
+++ b/Documentation/arm/README
@@ -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)
--
1.9.1
On Tue, 3 Feb 2015 18:49:26 -0800
Gregory Fong <[email protected]> wrote:
> 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.
It seems nobody has complained about this, so I've just applied it to the
docs tree.
Thanks,
jon