X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=Documentation%2Fpowerpc%2Fbooting-without-of.txt;h=06141cb200fa0734df549ebed4f6536aeba4409f;hb=3b824f85191c9ccc2614474543118e88543d5ba2;hp=d4bfae75c9465edf74328d2348ffa34773955b39;hpb=6ec129c3a2f8b38bc37e42348470ccfcb7460146;p=linux-2.6 diff --git a/Documentation/powerpc/booting-without-of.txt b/Documentation/powerpc/booting-without-of.txt index d4bfae75c9..06141cb200 100644 --- 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 , IBM Corp. (c) 2005 Becky Bruce , @@ -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 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, @@ -1444,7 +1508,7 @@ platforms are moved over to use the flattened-device-tree model. Basically, it is a bus of devices, that could act more or less as a complete entity (UCC, USB etc ). All of them should be siblings on the "root" qe node, using the common properties from there. - The description below applies to the the qe of MPC8360 and + The description below applies to the qe of MPC8360 and more nodes and properties would be extended in the future. i) Root QE device @@ -1633,7 +1697,7 @@ platforms are moved over to use the flattened-device-tree model. - assignment : function number of the pin according to the Pin Assignment tables in User Manual. Each pin can have up to 4 possible functions in QE and two options for CPM. - - has_irq : indicates if the pin is used as source of exteral + - has_irq : indicates if the pin is used as source of external interrupts. Example: @@ -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 = ; + fsl,has-rstcr; + }; + More devices will be defined as this spec matures. VII - Specifying interrupt information for devices