arm32 support for UFIs

[185264646]

All of them already have arm64 support in mainline. But for the following reasons, it might be appropriate to add arm32 aupport:

1. arm64 is only supoorted with an updated tz. It's quite dangerous to flash tz, and it will break the downstream Android system.
2. arm64 consumes more RAM than arm32, which can not be ignored due to only 512 MiB of RAM (only ~320MiB available) for these devices.

So add arm32 support for them, even when arm64 is available.

Not tested yet.

[stephan-gh]

Would appreciate if you send this upstream after testing.

[stephan-gh]

ARM32 dts commit style is ARM: dts: qcom: ...

[185264646]

Would appreciate if you send this upstream after testing.

Sure.

ARM32 dts commit style is ARM: dts: qcom: ...

Will fix later.

[ttimasdf]

I own a ufi001c device which could help testing this patch, but before hands on it I have some concerns,

1. Are there any documentations or basic explanations about the differences of tz firmwares? I'm currently running a community-packaged arm64 Debian image (OpenStick) but the maintainer didn't provide any information on this. This device ships with an 32bit arm Android image, so I assume that reflash the stock tz firmware should be enough?
   
2. How much memory could this device benefit from a 32bit system comparing to the original one?

[185264646]

I own a ufi001c device which could help testing this patch, but before hands on it I have some concerns,

1. Are there any documentations or basic explanations about the differences of tz firmwares? I'm currently running a community-packaged arm64 Debian image (OpenStick) but the maintainer didn't provide any information on this. This device ships with an 32bit arm Android image, so I assume that reflash the stock tz firmware should be enough?

Read the relevant pmos wiki page pls. https://wiki.postmarketos.org/wiki/Zhihe_series_LTE_dongles_(generic-zhihe)
I think you can keep new tz as-is. It's compatible with both 64/32 bits OS.

2. How much memory could this device benefit from a 32bit system comparing to the original one?

I have no idea actually. I've never booted a 32bit kernel and userspace yet. But most RAM are reserved for modem so you can try disable the modem if you don't need a cellular network. It'll free up ~80MB of RAM.