sys: Simplify enabling EARLY_PRINTF uarts
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Authored by andrew on Jan 8 2024, 5:26 PM.

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imp
manu

Group Reviewers

ARM
arm64

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rG202890922e31: sys: Simplify enabling EARLY_PRINTF uarts

Summary

Support selecting the early uart with "options EARLY_PRINTF=foo" in
the kernel configuration file. This allows us to not have to change
source files when enabling EARLY_PRINTF, simplifying enabling it.

New uart drivers can be enabled by defining a new early_printf_foo
value to be unique, then using "#if CHECK_EARLY_PRINTF(foo)" to decide
when to enable the uart.

While here add pl011 early printf support.

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rG FreeBSD src repository

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Buildable 55320
Build 52209: arc lint + arc unit

Event Timeline

andrew requested review of this revision.Jan 8 2024, 5:26 PM

andrew created this revision.

Harbormaster completed remote builds in B55291: Diff 132436.Jan 8 2024, 5:26 PM

andrew added a parent revision: D43359: arm: Clean up socdev_va.Jan 8 2024, 5:26 PM

andrew added a child revision: D43361: dev/uart: Use a linker set to find uart classes.

What do existing kernel configs do with the new system? Looks like a compile error from the pre-processor when early_printf_ isn't defined.
If so, that's fine. there's half a dozen ways to do this, and this one is more straight forward to diagnose problems with and to understand the code and if the old config file is the only issue, people using this option have the skills to debug the change. An UPDATING entry wouldn't be bad though to document the change.

sys/dev/uart/uart_dev_ns8250.c
88	Do you need quotes around the error message? We're about 50/50 in the kernel. I think they are only required syntactically when there's weird quotes etc. style(9) is silent on the issue and the #errors in the kernel are a mixed bag: 342 / 675 have quotes.

This revision is now accepted and ready to land.Jan 8 2024, 6:14 PM

manu accepted this revision.Jan 8 2024, 6:20 PM

Check for "options EARLY_PRINTF" and report why the build failed

This revision now requires review to proceed.Jan 9 2024, 11:54 AM

Harbormaster completed remote builds in B55320: Diff 132486.Jan 9 2024, 11:55 AM

It checks for early_printf_1. I've added a check for this with a #error to tell the user what the issue is.