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Diffstat (limited to 'Documentation/powerpc/dts-bindings/mtd-physmap.txt')
| -rw-r--r-- | Documentation/powerpc/dts-bindings/mtd-physmap.txt | 42 |
1 files changed, 26 insertions, 16 deletions
diff --git a/Documentation/powerpc/dts-bindings/mtd-physmap.txt b/Documentation/powerpc/dts-bindings/mtd-physmap.txt index 667c9bd..80152cb 100644 --- a/Documentation/powerpc/dts-bindings/mtd-physmap.txt +++ b/Documentation/powerpc/dts-bindings/mtd-physmap.txt @@ -1,18 +1,19 @@ -CFI or JEDEC memory-mapped NOR flash +CFI or JEDEC memory-mapped NOR flash, MTD-RAM (NVRAM...) Flash chips (Memory Technology Devices) are often used for solid state file systems on embedded devices. - - compatible : should contain the specific model of flash chip(s) - used, if known, followed by either "cfi-flash" or "jedec-flash" - - reg : Address range(s) of the flash chip(s) + - compatible : should contain the specific model of mtd chip(s) + used, if known, followed by either "cfi-flash", "jedec-flash" + or "mtd-ram". + - reg : Address range(s) of the mtd chip(s) It's possible to (optionally) define multiple "reg" tuples so that - non-identical NOR chips can be described in one flash node. - - bank-width : Width (in bytes) of the flash bank. Equal to the + non-identical chips can be described in one node. + - bank-width : Width (in bytes) of the bank. Equal to the device width times the number of interleaved chips. - - device-width : (optional) Width of a single flash chip. If + - device-width : (optional) Width of a single mtd chip. If omitted, assumed to be equal to 'bank-width'. - - #address-cells, #size-cells : Must be present if the flash has + - #address-cells, #size-cells : Must be present if the device has sub-nodes representing partitions (see below). In this case both #address-cells and #size-cells must be equal to 1. @@ -22,24 +23,24 @@ are defined: - vendor-id : Contains the flash chip's vendor id (1 byte). - device-id : Contains the flash chip's device id (1 byte). -In addition to the information on the flash bank itself, the +In addition to the information on the mtd bank itself, the device tree may optionally contain additional information -describing partitions of the flash address space. This can be +describing partitions of the address space. This can be used on platforms which have strong conventions about which -portions of the flash are used for what purposes, but which don't +portions of a flash are used for what purposes, but which don't use an on-flash partition table such as RedBoot. -Each partition is represented as a sub-node of the flash device. +Each partition is represented as a sub-node of the mtd device. Each node's name represents the name of the corresponding -partition of the flash device. +partition of the mtd device. Flash partitions - - reg : The partition's offset and size within the flash bank. - - label : (optional) The label / name for this flash partition. + - reg : The partition's offset and size within the mtd bank. + - label : (optional) The label / name for this partition. If omitted, the label is taken from the node name (excluding the unit address). - read-only : (optional) This parameter, if present, is a hint to - Linux that this flash partition should only be mounted + Linux that this partition should only be mounted read-only. This is usually used for flash partitions containing early-boot firmware images or data which should not be clobbered. @@ -78,3 +79,12 @@ Here an example with multiple "reg" tuples: reg = <0 0x04000000>; }; }; + +An example using SRAM: + + sram@2,0 { + compatible = "samsung,k6f1616u6a", "mtd-ram"; + reg = <2 0 0x00200000>; + bank-width = <2>; + }; + |