X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=Documentation%2Fdevicetree%2Fbooting-without-of.txt;h=50619a0720a8fd070b5f83cb1fc9ced9ff79a858;hp=28b1c9d3d3514b9afdc27c92bd585b9982ecb6db;hb=18770c7c3a0ccd60017ac76b5d2e7d1f71376b94;hpb=ce24f58a1187ca3058d72c3f897e3b574209ab20 diff --git a/Documentation/devicetree/booting-without-of.txt b/Documentation/devicetree/booting-without-of.txt index 28b1c9d3d351..50619a0720a8 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 @@ -137,7 +138,7 @@ and properties to be present. This will be described in detail in section III, but, for example, the kernel does not require you to create a node for every PCI device in the system. It is a requirement to have a node for PCI host bridges in order to provide interrupt -routing informations and memory/IO ranges, among others. It is also +routing information and memory/IO ranges, among others. It is also recommended to define nodes for on chip devices and other buses that don't specifically fit in an existing OF specification. This creates a great flexibility in the way the kernel can then probe those and match @@ -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 ======================== @@ -365,7 +385,7 @@ struct boot_param_header { among others, by kexec. If you are on an SMP system, this value should match the content of the "reg" property of the CPU node in the device-tree corresponding to the CPU calling the kernel entry - point (see further chapters for more informations on the required + point (see further chapters for more information on the required device-tree contents) - size_dt_strings @@ -533,7 +553,7 @@ looks like in practice. This tree is almost a minimal tree. It pretty much contains the minimal set of required nodes and properties to boot a linux kernel; -that is, some basic model informations at the root, the CPUs, and the +that is, some basic model information at the root, the CPUs, and the physical memory layout. It also includes misc information passed through /chosen, like in this example, the platform type (mandatory) and the kernel command line arguments (optional).