[POWERPC] Document the global utilities node define and example

[linux-2.6] / Documentation / powerpc / booting-without-of.txt

diff --git a/Documentation/powerpc/booting-without-of.txt b/Documentation/powerpc/booting-without-of.txt
index b49ce169a63aa27d75271a45948b0c1ed8d15ecd..06141cb200fa0734df549ebed4f6536aeba4409f 100644 (file)
--- a/Documentation/powerpc/booting-without-of.txt
+++ b/Documentation/powerpc/booting-without-of.txt
@@ -1,7 +1,6 @@
            Booting the Linux/ppc kernel without Open Firmware
            --------------------------------------------------
 
-
 (c) 2005 Benjamin Herrenschmidt <benh at kernel.crashing.org>,
     IBM Corp.
 (c) 2005 Becky Bruce <becky.bruce at freescale.com>,
@@ -9,6 +8,63 @@
 (c) 2006 MontaVista Software, Inc.
     Flash chip node definition
 
+Table of Contents
+=================
+
+  I - Introduction
+    1) Entry point for arch/powerpc
+    2) Board support
+
+  II - The DT block format
+    1) Header
+    2) Device tree generalities
+    3) Device tree "structure" block
+    4) Device tree "strings" block
+
+  III - Required content of the device tree
+    1) Note about cells and address representation
+    2) Note about "compatible" properties
+    3) Note about "name" properties
+    4) Note about node and property names and character set
+    5) Required nodes and properties
+      a) The root node
+      b) The /cpus node
+      c) The /cpus/* nodes
+      d) the /memory node(s)
+      e) The /chosen node
+      f) the /soc<SOCname> node
+
+  IV - "dtc", the device tree compiler
+
+  V - Recommendations for a bootloader
+
+  VI - System-on-a-chip devices and nodes
+    1) Defining child nodes of an SOC
+    2) Representing devices without a current OF specification
+      a) MDIO IO device
+      c) PHY nodes
+      b) Gianfar-compatible ethernet nodes
+      d) Interrupt controllers
+      e) I2C
+      f) Freescale SOC USB controllers
+      g) Freescale SOC SEC Security Engines
+      h) Board Control and Status (BCSR)
+      i) Freescale QUICC Engine module (QE)
+      g) Flash chip nodes
+      k) Global Utilities Block
+
+  VII - Specifying interrupt information for devices
+    1) interrupts property
+    2) interrupt-parent property
+    3) OpenPIC Interrupt Controllers
+    4) ISA Interrupt Controllers
+
+  Appendix A - Sample SOC node for MPC8540
+
+
+Revision Information
+====================
+
    May 18, 2005: Rev 0.1 - Initial draft, no chapter III yet.
 
    May 19, 2005: Rev 0.2 - Add chapter III and bits & pieces here or
@@ -571,6 +627,14 @@ So the node content can be summarized as a start token, a full path,
 a list of properties, a list of child nodes, and an end token. Every
 child node is a full node structure itself as defined above.
 
+NOTE: The above definition requires that all property definitions for
+a particular node MUST precede any subnode definitions for that node.
+Although the structure would not be ambiguous if properties and
+subnodes were intermingled, the kernel parser requires that the
+properties come first (up until at least 2.6.22).  Any tools
+manipulating a flattened tree must take care to preserve this
+constraint.
+
 4) Device tree "strings" block
 
 In order to save space, property names, which are generally redundant,
@@ -1687,7 +1751,7 @@ platforms are moved over to use the flattened-device-tree model.
                };
        };
 
-    g) Flash chip nodes
+    j) Flash chip nodes
 
     Flash chips (Memory Technology Devices) are often used for solid state
     file systems on embedded devices.
@@ -1727,6 +1791,33 @@ platforms are moved over to use the flattened-device-tree model.
                partition-names = "fs\0firmware";
        };
 
+   k) Global Utilities Block
+
+   The global utilities block controls power management, I/O device
+   enabling, power-on-reset configuration monitoring, general-purpose
+   I/O signal configuration, alternate function selection for multiplexed
+   signals, and clock control.
+
+   Required properties:
+
+    - compatible : Should define the compatible device type for
+      global-utilities.
+    - reg : Offset and length of the register set for the device.
+
+  Recommended properties:
+
+    - fsl,has-rstcr : Indicates that the global utilities register set
+      contains a functioning "reset control register" (i.e. the board
+      is wired to reset upon setting the HRESET_REQ bit in this register).
+
+    Example:
+
+       global-utilities@e0000 {        /* global utilities block */
+               compatible = "fsl,mpc8548-guts";
+               reg = <e0000 1000>;
+               fsl,has-rstcr;
+       };
+
    More devices will be defined as this spec matures.
 
 VII - Specifying interrupt information for devices