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Diffstat (limited to 'Documentation/devicetree/bindings/mtd/partitions')
-rw-r--r-- | Documentation/devicetree/bindings/mtd/partitions/brcm,bcm947xx-cfe-partitions.txt | 42 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/mtd/partitions/brcm,trx.txt | 37 |
2 files changed, 79 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/mtd/partitions/brcm,bcm947xx-cfe-partitions.txt b/Documentation/devicetree/bindings/mtd/partitions/brcm,bcm947xx-cfe-partitions.txt new file mode 100644 index 000000000..1d61a0293 --- /dev/null +++ b/Documentation/devicetree/bindings/mtd/partitions/brcm,bcm947xx-cfe-partitions.txt @@ -0,0 +1,42 @@ +Broadcom BCM47xx Partitions +=========================== + +Broadcom is one of hardware manufacturers providing SoCs (BCM47xx) used in +home routers. Their BCM947xx boards using CFE bootloader have several partitions +without any on-flash partition table. On some devices their sizes and/or +meanings can also vary so fixed partitioning can't be used. + +Discovering partitions on these devices is possible thanks to having a special +header and/or magic signature at the beginning of each of them. They are also +block aligned which is important for determinig a size. + +Most of partitions use ASCII text based magic for determining a type. More +complex partitions (like TRX with its HDR0 magic) may include extra header +containing some details, including a length. + +A list of supported partitions includes: +1) Bootloader with Broadcom's CFE (Common Firmware Environment) +2) NVRAM with configuration/calibration data +3) Device manufacturer's data with some default values (e.g. SSIDs) +4) TRX firmware container which can hold up to 4 subpartitions +5) Backup TRX firmware used after failed upgrade + +As mentioned earlier, role of some partitions may depend on extra configuration. +For example both: main firmware and backup firmware use the same TRX format with +the same header. To distinguish currently used firmware a CFE's environment +variable "bootpartition" is used. + + +Devices using Broadcom partitions described above should should have flash node +with a subnode named "partitions" using following properties: + +Required properties: +- compatible : (required) must be "brcm,bcm947xx-cfe-partitions" + +Example: + +flash@0 { + partitions { + compatible = "brcm,bcm947xx-cfe-partitions"; + }; +}; diff --git a/Documentation/devicetree/bindings/mtd/partitions/brcm,trx.txt b/Documentation/devicetree/bindings/mtd/partitions/brcm,trx.txt new file mode 100644 index 000000000..b677147ca --- /dev/null +++ b/Documentation/devicetree/bindings/mtd/partitions/brcm,trx.txt @@ -0,0 +1,37 @@ +Broadcom TRX Container Partition +================================ + +TRX is Broadcom's official firmware format for the BCM947xx boards. It's used by +most of the vendors building devices based on Broadcom's BCM47xx SoCs and is +supported by the CFE bootloader. + +Design of the TRX format is very minimalistic. Its header contains +identification fields, CRC32 checksum and the locations of embedded partitions. +Its purpose is to store a few partitions in a format that can be distributed as +a standalone file and written in a flash memory. + +Container can hold up to 4 partitions. The first partition has to contain a +device executable binary (e.g. a kernel) as it's what the CFE bootloader starts +executing. Other partitions can be used for operating system purposes. This is +useful for systems that keep kernel and rootfs separated. + +TRX doesn't enforce any strict partition boundaries or size limits. All +partitions have to be less than the 4GiB max size limit. + +There are two existing/known TRX variants: +1) v1 which contains 3 partitions +2) v2 which contains 4 partitions + +There aren't separated compatible bindings for them as version can be trivialy +detected by a software parsing TRX header. + +Required properties: +- compatible : (required) must be "brcm,trx" + +Example: + +flash@0 { + partitions { + compatible = "brcm,trx"; + }; +}; |