Support a default memory bank, specified in reg, as well as board-specific memory banks in subtree board-id nodes. This allows memory information to be provided in the device tree, rather than hard-coded in, which will make it simpler to handle similar devices with different memory banks, as the board-id values or masks can be used to match devices. Signed-off-by: Michael Pratt <mpratt@chromium.org> Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>lime2-spi
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* Memory binding |
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The memory binding for U-Boot is as in the ePAPR with the following additions: |
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Optional subnodes can be used defining the memory layout for different board |
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ID masks. To match a set of board ids, a board-id node may define match-mask |
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and match-value ints to define a mask to apply to the board id, and the value |
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that the result should have for the match to be considered valid. The mask |
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defaults to -1, meaning that the value must fully match the board id. |
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If subnodes are present, then the /memory node must define these properties: |
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- #address-cells: should be 1. |
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- #size-cells: should be 0. |
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Each subnode must define |
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reg - board ID or mask for this subnode |
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memory-banks - list of memory banks in the same format as normal |
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Each subnode may optionally define: |
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match-mask - A mask to apply to the board id. This must be accompanied by |
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match-value. |
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match-value - The required resulting value of the board id mask for the given |
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node to be considered a match. |
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auto-size - Indicates that the value given for a bank is the maximum size, |
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each bank is probed to determine its actual size, which may be |
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smaller |
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The board id determination is up to the vendor and is not defined by this |
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binding. |
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Example: |
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memory { |
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#address-cells = <1>; |
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#size-cells = <1>; |
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reg = <0x20000000 0x20000000 |
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0x40000000 0x20000000 |
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0x60000000 0x20000000 |
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0x80000000 0x20000000>; |
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auto-size; |
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board-id@0 { |
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match-value = <17>; |
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reg = <0x20000000 0x20000000 |
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0x40000000 0x20000000>; |
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}; |
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board-id@1 { |
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match-mask = <2>; |
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match-value = <2>; |
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reg = <0x20000000 0x20000000 |
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0x40000000 0x20000000 |
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0x60000000 0x20000000 |
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0x80000000 0x20000000 |
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0xa0000000 0x20000000 |
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0xc0000000 0x20000000 |
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0xe0000000 0x20000000>; |
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}; |
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}; |
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This shows a system with the following properties: |
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* Default of 2GB of memory, auto-sized, so could be smaller |
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* 3.5GB of memory (with no auto-size) if (board id & 2) is 2 |
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* 1GB of memory (with no auto-size) if board id is 17. |
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