add eMMC installer workflow

[katiaTsaruk]

Summary:

Added documentation for the eMMC installer workflow: flashing the image, booting Linux from eMMC and default login credentials.

Note:

The image is served compressed (.gz) as a temporary workaround for a suspected race condition in the SC598 MMC kernel driver that causes a crash under memory pressure when streaming the raw 7.6 GB image. This will be reverted once the driver bug is fixed.

Type

• Documentation
• Bug fix
• New feature
• Continuous integration

Checklist

• I have performed a self-review of changes
• I have followed the guidelines:
  • https://analogdevicesinc.github.io/documentation/contributing/docs_guidelines.html
  • https://analogdevicesinc.github.io/doctools/docs_guidelines/index.html
  • https://analogdevicesinc.github.io/documentation/contributing/creating_new_pages.html#documentation-structure
• I have used the appropriate roles and directives:
  • https://analogdevicesinc.github.io/doctools/docs_guidelines/roles.html
  • https://analogdevicesinc.github.io/doctools/docs_guidelines/directives.html
• I ensured that binary data was committed to git lfs:
  • https://analogdevicesinc.github.io/documentation/contributing/creating_new_pages.html#adding-images-and-other-binary-files
• I have built the pages I edited or created, using either make html or adoc serve:
  • https://analogdevicesinc.github.io/doctools/cli.html#serve
• I have signed-off my commits and believe my contribution improves the repository.

[ozan956]

This may be slightly outside the scope of this PR, but the current flow confused me a bit.

As far as I understand it, the new bootstrap flow now depends on an emmc.img.gz artifact produced by the debug image build:

• SPI flash gets the U-Boot SPL and U-Boot binaries from the bootstrap image.
• eMMC gets the U-Boot SPL, U-Boot, device tree, kernel, and root filesystem from the debug/full image.

After that, the script asks the user to switch to SPI boot mode, so the expected flow appears to be:

• boot U-Boot from SPI NOR
• boot Linux from eMMC

If this is the intended bootstrap flow, then the current approach makes sense. However, I want to clarify the design direction because genimage.cfg also defines a SPI flash image that contains all. So in principle, we could support a few different installation flows such as SPI-NOR-only, eMMC-only, hybrid, etc.

The current script seems to enforce the hybrid flow by always requiring SPI programming first and always asking the user to switch to SPI boot mode afterward.

Is that the only flow we want to support for bootstrap installation, or should the installer allow the user to choose between bootstrap modes?

[gastmaier]

@pamolloy anything missing here?

[ozan956]

We normally can solve this by adding those keywords to:
.github/styles/config/vocabularies/Base/accept.txt

but im not sure whether thats the only solution

[pamolloy]

There are a couple examples of this already in the file. We'll need to fix them all at once later 😄