On Thu, Dec 28, 2023 at 07:47:25PM +0000, Simon Glass wrote:
Standard passage provides for a bloblist to be passed from one firmware phase to the next. That can be used to pass the devicetree along as well. Add an option to support this.
Tests for this will be added as part of the Universal Payload work.
Signed-off-by: Simon Glass sjg@chromium.org
[snip]
diff --git a/dts/Kconfig b/dts/Kconfig index 00c0aeff893..ae451b9caf7 100644 --- a/dts/Kconfig +++ b/dts/Kconfig @@ -105,6 +105,19 @@ config OF_EMBED
endchoice
+config OF_BLOBLIST
- bool "Provided by a bloblist at runtime"
- depends on BLOBLIST && OF_SEPARATE
This is now even more confusing, frankly. The help for OF_SEPARATE says: If this option is enabled, the device tree will be built and placed as a separate u-boot.dtb file alongside the U-Boot image.
So why would you enable that to then have a device tree passed via bloblist instead?
We should probably start by fixing all of this confusing naming / logic and then correct things such that: - OF_EMBED wins if set. This is the override-has-been-set we-must-use-it switch. First choice, not last choice. If binman needs tweaks so that it will still generate images for platforms in this case, that needs to happen. - If we have a bloblist, we scan the bloblist for DT and if found, use it. - If it looks like we've been booted as a fake Linux kernel, and we can start with just aarch64 and let riscv come in as a follow up, so what's documented within https://www.kernel.org/doc/html/latest/arch/arm64/booting.html#call-the-kern... then we use that device tree. - This _may_ just end up having to be "Does x0 (or similar) point to a valid DT?" as I don't know how correct everything using this method today is too what the spec above lists. - If we have a dtb appended to use by what we call today OF_SEPARATE but should really stop calling it that we use that.
At that point, we can probably have zero "totally board specific kludge for device tree location", and kill off OF_HAS_PRIOR_STAGE too (since that's really just bloblist or fake-linux-kernel). We'll also be able to support migration from fake-linux-kernel to bloblist