43 lines
1.6 KiB
Plaintext
43 lines
1.6 KiB
Plaintext
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Broadcom BCM47xx Partitions
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===========================
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Broadcom is one of hardware manufacturers providing SoCs (BCM47xx) used in
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home routers. Their BCM947xx boards using CFE bootloader have several partitions
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without any on-flash partition table. On some devices their sizes and/or
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meanings can also vary so fixed partitioning can't be used.
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Discovering partitions on these devices is possible thanks to having a special
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header and/or magic signature at the beginning of each of them. They are also
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block aligned which is important for determinig a size.
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Most of partitions use ASCII text based magic for determining a type. More
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complex partitions (like TRX with its HDR0 magic) may include extra header
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containing some details, including a length.
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A list of supported partitions includes:
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1) Bootloader with Broadcom's CFE (Common Firmware Environment)
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2) NVRAM with configuration/calibration data
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3) Device manufacturer's data with some default values (e.g. SSIDs)
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4) TRX firmware container which can hold up to 4 subpartitions
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5) Backup TRX firmware used after failed upgrade
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As mentioned earlier, role of some partitions may depend on extra configuration.
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For example both: main firmware and backup firmware use the same TRX format with
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the same header. To distinguish currently used firmware a CFE's environment
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variable "bootpartition" is used.
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Devices using Broadcom partitions described above should should have flash node
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with a subnode named "partitions" using following properties:
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Required properties:
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- compatible : (required) must be "brcm,bcm947xx-cfe-partitions"
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Example:
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flash@0 {
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partitions {
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compatible = "brcm,bcm947xx-cfe-partitions";
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};
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};
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