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Diffstat (limited to 'Documentation/devicetree/booting-without-of.txt')
| -rw-r--r-- | Documentation/devicetree/booting-without-of.txt | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/Documentation/devicetree/booting-without-of.txt b/Documentation/devicetree/booting-without-of.txt index 28b1c9d3d35..55fd2623445 100644 --- a/Documentation/devicetree/booting-without-of.txt +++ b/Documentation/devicetree/booting-without-of.txt @@ -13,6 +13,7 @@ Table of Contents I - Introduction 1) Entry point for arch/powerpc + 2) Entry point for arch/x86 II - The DT block format 1) Header @@ -225,6 +226,25 @@ it with special cases. cannot support both configurations with Book E and configurations with classic Powerpc architectures. +2) Entry point for arch/x86 +------------------------------- + + There is one single 32bit entry point to the kernel at code32_start, + the decompressor (the real mode entry point goes to the same 32bit + entry point once it switched into protected mode). That entry point + supports one calling convention which is documented in + Documentation/x86/boot.txt + The physical pointer to the device-tree block (defined in chapter II) + is passed via setup_data which requires at least boot protocol 2.09. + The type filed is defined as + + #define SETUP_DTB 2 + + This device-tree is used as an extension to the "boot page". As such it + does not parse / consider data which is already covered by the boot + page. This includes memory size, reserved ranges, command line arguments + or initrd address. It simply holds information which can not be retrieved + otherwise like interrupt routing or a list of devices behind an I2C bus. II - The DT block format ======================== |