diff options
Diffstat (limited to 'tools/binman/README')
| -rw-r--r-- | tools/binman/README | 41 |
1 files changed, 39 insertions, 2 deletions
diff --git a/tools/binman/README b/tools/binman/README index 196dda1fb4..5ef1246f29 100644 --- a/tools/binman/README +++ b/tools/binman/README @@ -392,6 +392,45 @@ either by using a unit number suffix (u-boot@0, u-boot@1) or by using a different name for each and specifying the type with the 'type' attribute. +Sections and hiearchical images +------------------------------- + +Sometimes it is convenient to split an image into several pieces, each of which +contains its own set of binaries. An example is a flash device where part of +the image is read-only and part is read-write. We can set up sections for each +of these, and place binaries in them independently. The image is still produced +as a single output file. + +This feature provides a way of creating hierarchical images. For example here +is an example with two copies of U-Boot. One is read-only (ro), intended to be +written only in the factory. Another is read-write (rw), so that it can be +upgraded in the field. The sizes are fixed so that the ro/rw boundary is known +and can be programmed: + + binman { + section@0 { + read-only; + size = <0x100000>; + u-boot { + }; + }; + section@1 { + size = <0x100000>; + u-boot { + }; + }; + }; + +This image could be placed into a SPI flash chip, with the protection boundary +set at 1MB. + +A few special properties are provided for sections: + +read-only: + Indicates that this section is read-only. This has no impact on binman's + operation, but his property can be read at run time. + + Special properties ------------------ @@ -586,8 +625,6 @@ Some ideas: - Allow easy building of images by specifying just the board name - Produce a full Python binding for libfdt (for upstream) - Add an option to decode an image into the constituent binaries -- Suppoort hierarchical images (packing of binaries into another binary - which is then placed in the image) - Support building an image for a board (-b) more completely, with a configurable build directory - Consider making binman work with buildman, although if it is used in the |