[PATCH 1/2] dt-bindings: mtd: document Broadcom's BCM47xx partitions
From: Rafał Miłecki <hidden>
Date: 2018-01-12 09:33:53
Subsystem:
memory technology devices (mtd), open firmware and flattened device tree bindings, the rest · Maintainers:
Miquel Raynal, Richard Weinberger, Vignesh Raghavendra, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds
From: Rafał Miłecki <redacted> Broadcom based home router devices use partitions which have to be discovered in a specific non-standard way. As there is no partition table this commit adds and describes a new custom binding. Signed-off-by: Rafał Miłecki <redacted> --- .../devicetree/bindings/mtd/partition.txt | 46 +++++++++++++++++++++- 1 file changed, 44 insertions(+), 2 deletions(-)
diff --git a/Documentation/devicetree/bindings/mtd/partition.txt b/Documentation/devicetree/bindings/mtd/partition.txt
index 36f3b769a626..b201d497b618 100644
--- a/Documentation/devicetree/bindings/mtd/partition.txt
+++ b/Documentation/devicetree/bindings/mtd/partition.txt@@ -14,8 +14,6 @@ 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. - Fixed Partitions ================
@@ -109,3 +107,47 @@ flash@2 { }; }; }; + + +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"; + }; +};
--
2.11.0
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at http://vger.kernel.org/majordomo-info.html