From dce12391d70d24d428def2f5fc600a3b1f791ca6 Mon Sep 17 00:00:00 2001 From: Gregory Fong Date: Tue, 3 Feb 2015 18:49:26 -0800 Subject: 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 Signed-off-by: Jonathan Corbet --- Documentation/arm/Booting | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'Documentation/arm/Booting') 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 ------------------ -- cgit v1.2.3