68 lines
2.0 KiB
Plaintext
68 lines
2.0 KiB
Plaintext
|
* Memory binding
|
||
|
|
|
||
|
|
The memory binding for U-Boot is as in the ePAPR with the following additions:
|
||
|
|
|
||
|
|
Optional subnodes can be used defining the memory layout for different board
|
||
|
|
ID masks. To match a set of board ids, a board-id node may define match-mask
|
||
|
|
and match-value ints to define a mask to apply to the board id, and the value
|
||
|
|
that the result should have for the match to be considered valid. The mask
|
||
|
|
defaults to -1, meaning that the value must fully match the board id.
|
||
|
|
|
||
|
|
If subnodes are present, then the /memory node must define these properties:
|
||
|
|
|
||
|
|
- #address-cells: should be 1.
|
||
|
|
- #size-cells: should be 0.
|
||
|
|
|
||
|
|
Each subnode must define
|
||
|
|
|
||
|
|
reg - board ID or mask for this subnode
|
||
|
|
memory-banks - list of memory banks in the same format as normal
|
||
|
|
|
||
|
|
Each subnode may optionally define:
|
||
|
|
|
||
|
|
match-mask - A mask to apply to the board id. This must be accompanied by
|
||
|
|
match-value.
|
||
|
|
match-value - The required resulting value of the board id mask for the given
|
||
|
|
node to be considered a match.
|
||
|
|
auto-size - Indicates that the value given for a bank is the maximum size,
|
||
|
|
each bank is probed to determine its actual size, which may be
|
||
|
|
smaller
|
||
|
|
|
||
|
|
|
||
|
|
The board id determination is up to the vendor and is not defined by this
|
||
|
|
binding.
|
||
|
|
|
||
|
|
Example:
|
||
|
|
|
||
|
|
memory {
|
||
|
|
#address-cells = <1>;
|
||
|
|
#size-cells = <1>;
|
||
|
|
reg = <0x20000000 0x20000000
|
||
|
|
0x40000000 0x20000000
|
||
|
|
0x60000000 0x20000000
|
||
|
|
0x80000000 0x20000000>;
|
||
|
|
auto-size;
|
||
|
|
board-id@0 {
|
||
|
|
match-value = <17>;
|
||
|
|
reg = <0x20000000 0x20000000
|
||
|
|
0x40000000 0x20000000>;
|
||
|
|
};
|
||
|
|
board-id@1 {
|
||
|
|
match-mask = <2>;
|
||
|
|
match-value = <2>;
|
||
|
|
reg = <0x20000000 0x20000000
|
||
|
|
0x40000000 0x20000000
|
||
|
|
0x60000000 0x20000000
|
||
|
|
0x80000000 0x20000000
|
||
|
|
0xa0000000 0x20000000
|
||
|
|
0xc0000000 0x20000000
|
||
|
|
0xe0000000 0x20000000>;
|
||
|
|
};
|
||
|
|
};
|
||
|
|
|
||
|
|
|
||
|
|
This shows a system with the following properties:
|
||
|
|
* Default of 2GB of memory, auto-sized, so could be smaller
|
||
|
|
* 3.5GB of memory (with no auto-size) if (board id & 2) is 2
|
||
|
|
* 1GB of memory (with no auto-size) if board id is 17.
|