arm64: csdlock at early boot due to slow serial (?)
Leo Yan
leo.yan at arm.com
Thu Jul 3 04:45:57 PDT 2025
On Thu, Jul 03, 2025 at 03:02:39AM -0700, Breno Leitao wrote:
[...]
> > In some cases, if normal world and secure world share the same UART
> > port, it can cause the UART state machine malfunction and long wait.
>
> I don't know how to check it for sure, but, looking at the serial
> console output, I don't see anything else using the UART. The only
> output I see on the console at that time is coming from linux kernel.
>
> Would you recommend any additional check?
I have no experience in the driver, I should avoid any noise. But two
things in my head for quick trying.
- First, you could try earlycon mode, e.g., add option in kernel
command line:
earlycon=pl011,mmio32,0xc280000
earlycon=pl011,0xc280000
This would be possible to give more printing logs. If earlycon works
well, then the issue might be caused by later init code (clock, or
UART driver itself).
- Try another UART port if this is possible.
Just curious, you mentioned you are working on the mainline kernel. If
you can confirm a workable kernel version, then this info can help to
rule out hardware issue and we can review the delta changes.
Thanks,
Leo
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