diff options
| author | Simon Glass <sjg@chromium.org> | 2021-12-16 20:59:35 -0700 |
|---|---|---|
| committer | Tom Rini <trini@konsulko.com> | 2021-12-23 10:24:40 -0500 |
| commit | 275b4832f6bf91ca723430efe93be06e4f07430d (patch) | |
| tree | 5e06b1267d68dbcbff15bea3cde1e2458340ee03 /README | |
| parent | ff66e7bb73233a4decfcdb66b7a858399dbccf50 (diff) | |
fdt: Add a Kconfig for boards with a prior stage
When U-Boot is started from another firmware program, not just a prior
phase of U-Boot, special behaviour is typically used. In particular, the
device tree may come from that prior stage.
At present this is sort-of indicated by OF_BOARD, although the
correlation is not 1:1, since that option simply means that the board has
a custom mechanism for obtaining the device tree. For example, sandbox
defines OF_BOARD. Also the board_fdt_blob_setup() function can in fact
make use of the devicetree in U-Boot if it wishes, as used by
dragonboard410c until very recently.
Add an explicit Kconfig for this situation. Update the OF_BOARD option to
more-accurately reflect what it is doing, e.g. for sandbox.
Drop the docs in the README as it is out of date.
Signed-off-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'README')
| -rw-r--r-- | README | 29 |
1 files changed, 0 insertions, 29 deletions
@@ -646,35 +646,6 @@ The following options need to be configured: which adds regex support to some commands, as for example "env grep" and "setexpr". -- Device tree: - CONFIG_OF_CONTROL - If this variable is defined, U-Boot will use a device tree - to configure its devices, instead of relying on statically - compiled #defines in the board file. This option is - experimental and only available on a few boards. The device - tree is available in the global data as gd->fdt_blob. - - U-Boot needs to get its device tree from somewhere. This can - be done using one of the three options below: - - CONFIG_OF_SEPARATE - If this variable is defined, U-Boot will build a device tree - binary. It will be called u-boot.dtb. Architecture-specific - code will locate it at run-time. Generally this works by: - - cat u-boot.bin u-boot.dtb >image.bin - - and in fact, U-Boot does this for you, creating a file called - u-boot-dtb.bin which is useful in the common case. You can - still use the individual files if you need something more - exotic. - - CONFIG_OF_BOARD - If this variable is defined, U-Boot will use the device tree - provided by the board at runtime instead of embedding one with - the image. Only boards defining board_fdt_blob_setup() support - this option (see include/fdtdec.h file). - - Watchdog: CONFIG_WATCHDOG If this variable is defined, it enables watchdog |