path: root/Documentation
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authorRich Felker <>2016-01-23 00:45:41 +0000
committerRich Felker <>2016-03-17 19:46:11 +0000
commit7480e0aabd5f9e6c3e3b72ed206e89284e90f11f (patch)
treeafcdb346dbec13ea4be79f062e9f849caedceaae /Documentation
parent45624ac38926c8c2f1a63b4a39e7b1997743e1b3 (diff)
sh: add device tree support and generic board using device tree
Add a new pseudo-board, within the existing SH boards/machine-vectors framework, which does not represent any actual hardware but instead requires all hardware to be described by the device tree blob provided by the boot loader. Changes made are thus non-invasive and do not risk breaking support for legacy boards. New hardware, including the open-hardware J2 and associated SoC devices, will use device free from the outset. Legacy SH boards can transition to device tree once all their hardware has device tree bindings, driver support for device tree, and a dts file for the board. It is intented that, once all boards are supported in the new framework, the existing machine-vectors framework should be removed and the new device tree setup code integrated directly. Signed-off-by: Rich Felker <>
Diffstat (limited to 'Documentation')
1 files changed, 13 insertions, 0 deletions
diff --git a/Documentation/devicetree/booting-without-of.txt b/Documentation/devicetree/booting-without-of.txt
index 04d34f6a58f3..3f1437fbca6b 100644
--- a/Documentation/devicetree/booting-without-of.txt
+++ b/Documentation/devicetree/booting-without-of.txt
@@ -16,6 +16,7 @@ Table of Contents
2) Entry point for arch/powerpc
3) Entry point for arch/x86
4) Entry point for arch/mips/bmips
+ 5) Entry point for arch/sh
II - The DT block format
1) Header
@@ -316,6 +317,18 @@ it with special cases.
This convention is defined for 32-bit systems only, as there are not
currently any 64-bit BMIPS implementations.
+5) Entry point for arch/sh
+ Device-tree-compatible SH bootloaders are expected to provide the physical
+ address of the device tree blob in r4. Since legacy bootloaders did not
+ guarantee any particular initial register state, kernels built to
+ inter-operate with old bootloaders must either use a builtin DTB or
+ select a legacy board option (something other than CONFIG_SH_DEVICE_TREE)
+ that does not use device tree. Support for the latter is being phased out
+ in favor of device tree.
II - The DT block format