Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 5178b99c authored by Rafał Miłecki's avatar Rafał Miłecki Committed by Boris Brezillon
Browse files

dt-bindings: mtd: document Broadcom's BCM47xx partitions 



Broadcom based home router devices use partitions which have to be
discovered in a specific way. They are not fixed and there is not any
standard partition table. This commit adds and describes a new custom
binding for such devices.

Signed-off-by: default avatarRafał Miłecki <rafal@milecki.pl>
Reviewed-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@bootlin.com>
parent ea092fb3

Documentation/devicetree/bindings/mtd/partition.txt

+1 −1
Original line number Diff line number Diff line
@@ -14,7 +14,7 @@ method is used for a given flash device. To describe the method there should be 
a subnode of the flash device that is named 'partitions'. It must have a

'compatible' property, which is used to identify the method to use.



We currently only document a binding for fixed layouts.

Available bindings are listed in the "partitions" subdirectory.





Fixed Partitions

Documentation/devicetree/bindings/mtd/partitions/brcm,bcm947xx-cfe-partitions.txt

0 → 100644
+42 −0
Original line number Diff line number Diff line 
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";

	};

};