This now better describes what the UBoot device tree generator actually does.
In particular:
1) Nodes have a label derived from the device name, and a node name
derived from the device type.
2) Usage of compound nodes (representing more than one device in the same IP)
which actually works. This requires having a valid compatible node, and all
the other things that a bus normally has. I've chosen 'xlnx,compound' as the
bus name to describe these compound nodes.
3) Uartlite requires a port-number property for the console to work.
In addition, I've clarified some of the language relating to how mhs
nodes should be represent in the device tree.
---
Documentation/powerpc/booting-without-of.txt | 61 +++++++++++++++-----------
1 files changed, 36 insertions(+), 25 deletions(-)
diff --git a/Documentation/powerpc/booting-without-of.txt
b/Documentation/powerpc/booting-without-of.txt
index e9a3cb1..5e2b85a 100644
--- a/Documentation/powerpc/booting-without-of.txt
+++ b/Documentation/powerpc/booting-without-of.txt
@@ -2276,7 +2276,7 @@ platforms are moved over to use the flattened-device-tree
model.
properties of the device node. In general, device nodes for IP-cores
will take the following form:
- (name)@(base-address) {
+ (name): (ip-core-name)@(base-address) {
compatible = "xlnx,(ip-core-name)-(HW_VER)"
[, (list of compatible devices), ...];
reg = <(baseaddr) (size)>;
@@ -2294,9 +2294,9 @@ platforms are moved over to use the flattened-device-tree
model.
dropped from the parameter name, the name is converted
to lowercase and all underscore '_' characters are
converted to dashes '-'.
- (baseaddr): the C_BASEADDR parameter.
+ (baseaddr): the baseaddr parameter value (often named C_BASEADDR).
(HW_VER): from the HW_VER parameter.
- (size): equals C_HIGHADDR - C_BASEADDR + 1
+ (size): the address range size (often C_HIGHADDR - C_BASEADDR +
1).
Typically, the compatible list will include the exact IP core version
followed by an older IP core version which implements the same
@@ -2326,12 +2326,13 @@ platforms are moved over to use the
flattened-device-tree model.
becomes the following device tree node:
- [EMAIL PROTECTED] {
+ opb_uartlite_0: [EMAIL PROTECTED] {
device_type = "serial";
compatible = "xlnx,opb-uartlite-1.00.b";
reg = <ec100000 10000>;
- interrupt-parent = <&opb-intc>;
+ interrupt-parent = <&opb_intc_0>;
interrupts = <1 0>; // got this from the opb_intc parameters
+ port-number = <0>;
current-speed = <d#115200>; // standard serial device prop
clock-frequency = <d#50000000>; // standard serial device prop
xlnx,data-bits = <8>;
@@ -2339,16 +2340,19 @@ platforms are moved over to use the
flattened-device-tree model.
xlnx,use-parity = <0>;
};
- Some IP cores actually implement 2 or more logical devices. In this case,
- the device should still describe the whole IP core with a single node
- and add a child node for each logical device. The ranges property can
- be used to translate from parent IP-core to the registers of each device.
- (Note: this makes the assumption that both logical devices have the same
- bus binding. If this is not true, then separate nodes should be used for
- each logical device). The 'cell-index' property can be used to enumerate
- logical devices within an IP core. For example, the following is the
- system.mhs entry for the dual ps2 controller found on the ml403 reference
- design.
+ Some IP cores actually implement 2 or more logical devices. In
+ this case, the device should still describe the whole IP core with
+ a single node and add a child node for each logical device. The
+ ranges property can be used to translate from parent IP-core to the
+ registers of each device. In addition, the parent node should be
+ compatible with the bus type 'xlnx,compound', and should contain
+ #address-cells and #size-cells, as with any other bus. (Note: this
+ makes the assumption that both logical devices have the same bus
+ binding. If this is not true, then separate nodes should be used
+ for each logical device). The 'cell-index' property can be used to
+ enumerate logical devices within an IP core. For example, the
+ following is the system.mhs entry for the dual ps2 controller found
+ on the ml403 reference design.
BEGIN opb_ps2_dual_ref
PARAMETER INSTANCE = opb_ps2_dual_ref_0
@@ -2370,21 +2374,24 @@ platforms are moved over to use the
flattened-device-tree model.
It would result in the following device tree nodes:
- [EMAIL PROTECTED] {
+ opb_ps2_dual_ref_0: [EMAIL PROTECTED] {
+ #address-cells = <1>;
+ #size-cells = <1>;
+ compatible = "xlnx,compound";
ranges = <0 a9000000 2000>;
// If this device had extra parameters, then they would
// go here.
- [EMAIL PROTECTED] {
+ [EMAIL PROTECTED] {
compatible = "xlnx,opb-ps2-dual-ref-1.00.a";
reg = <0 40>;
- interrupt-parent = <&opb-intc>;
+ interrupt-parent = <&opb_intc_0>;
interrupts = <3 0>;
cell-index = <0>;
};
- [EMAIL PROTECTED] {
+ [EMAIL PROTECTED] {
compatible = "xlnx,opb-ps2-dual-ref-1.00.a";
reg = <1000 40>;
- interrupt-parent = <&opb-intc>;
+ interrupt-parent = <&opb_intc_0>;
interrupts = <3 0>;
cell-index = <0>;
};
@@ -2447,17 +2454,18 @@ platforms are moved over to use the
flattened-device-tree model.
Gives this device tree (some properties removed for clarity):
- plb-v34-0 {
+ plb_v34 {
#address-cells = <1>;
#size-cells = <1>;
+ compatible = "xlnx,plb-v34-1.02.a";
device_type = "ibm,plb";
ranges; // 1:1 translation
- [EMAIL PROTECTED] {
+ plb_bram_if_cntrl_0: [EMAIL PROTECTED] {
reg = <ffff0000 10000>;
}
- opb-v20-0 {
+ opb_v20 {
#address-cells = <1>;
#size-cells = <1>;
ranges = <20000000 20000000 20000000
@@ -2465,11 +2473,11 @@ platforms are moved over to use the
flattened-device-tree model.
80000000 80000000 40000000
c0000000 c0000000 20000000>;
- [EMAIL PROTECTED] {
+ opb_uart16550_0: [EMAIL PROTECTED] {
reg = <a00000000 2000>;
};
- [EMAIL PROTECTED] {
+ opb_intc_0: [EMAIL PROTECTED] {
reg = <d1000fc0 20>;
};
};
@@ -2513,6 +2521,9 @@ platforms are moved over to use the flattened-device-tree
model.
Requred properties:
- current-speed : Baud rate of uartlite
+ Optional properties:
+ - port-number : unique ordinal index of the device. This
+ property is required for a console on uartlite.
More devices will be defined as this spec matures.
--
1.5.3.4
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