c5a88dd90c
Add binding for mtd nodes with multiple reg tuples. Multiple reg tuples are used when the flash region covers multiple devices of the same type, but not necessarily the same size. Signed-off-by: Stefan Roese <sr@denx.de> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
80 lines
2.7 KiB
Text
80 lines
2.7 KiB
Text
CFI or JEDEC memory-mapped NOR flash
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Flash chips (Memory Technology Devices) are often used for solid state
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file systems on embedded devices.
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- compatible : should contain the specific model of flash chip(s)
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used, if known, followed by either "cfi-flash" or "jedec-flash"
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- reg : Address range(s) of the flash chip(s)
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It's possible to (optionally) define multiple "reg" tuples so that
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non-identical NOR chips can be described in one flash node.
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- bank-width : Width (in bytes) of the flash bank. Equal to the
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device width times the number of interleaved chips.
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- device-width : (optional) Width of a single flash chip. If
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omitted, assumed to be equal to 'bank-width'.
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- #address-cells, #size-cells : Must be present if the flash has
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sub-nodes representing partitions (see below). In this case
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both #address-cells and #size-cells must be equal to 1.
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For JEDEC compatible devices, the following additional properties
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are defined:
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- vendor-id : Contains the flash chip's vendor id (1 byte).
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- device-id : Contains the flash chip's device id (1 byte).
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In addition to the information on the flash bank itself, the
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device tree may optionally contain additional information
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describing partitions of the flash address space. This can be
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used on platforms which have strong conventions about which
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portions of the flash are used for what purposes, but which don't
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use an on-flash partition table such as RedBoot.
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Each partition is represented as a sub-node of the flash device.
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Each node's name represents the name of the corresponding
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partition of the flash device.
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Flash partitions
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- reg : The partition's offset and size within the flash bank.
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- label : (optional) The label / name for this flash partition.
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If omitted, the label is taken from the node name (excluding
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the unit address).
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- read-only : (optional) This parameter, if present, is a hint to
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Linux that this flash partition should only be mounted
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read-only. This is usually used for flash partitions
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containing early-boot firmware images or data which should not
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be clobbered.
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Example:
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flash@ff000000 {
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compatible = "amd,am29lv128ml", "cfi-flash";
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reg = <ff000000 01000000>;
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bank-width = <4>;
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device-width = <1>;
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#address-cells = <1>;
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#size-cells = <1>;
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fs@0 {
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label = "fs";
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reg = <0 f80000>;
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};
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firmware@f80000 {
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label ="firmware";
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reg = <f80000 80000>;
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read-only;
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};
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};
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Here an example with multiple "reg" tuples:
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flash@f0000000,0 {
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#address-cells = <1>;
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#size-cells = <1>;
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compatible = "intel,PC48F4400P0VB", "cfi-flash";
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reg = <0 0x00000000 0x02000000
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0 0x02000000 0x02000000>;
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bank-width = <2>;
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partition@0 {
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label = "test-part1";
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reg = <0 0x04000000>;
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};
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};
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