[Sound-open-firmware] Generic panic handling

[Liam Girdwood]

On Mon, 2019-12-16 at 12:05 +0000, Paul Olaru (OSS) wrote:
> Hello, I would like panics on our DSP to actually be properly
> reported to the kernel.
> 
> Currently on the Intel platforms for panic there is custom code for
> each platform to
> e.g. read from the shim area and check with the panic magic mask
> whether there
> is a panic.
> 
> My suggestion is to instead craft a specific message type and a very
> short message
> (possibly only that one word with the panic mask, which will not be
> confused with
> a regular DSP request header) which is then handled in a generic
> fashion within
> snd_sof_ipc_msgs_rx.

Ok, so you mean have a global IPC type for panic and send as regular
IPC ?

> 
> I am aware that such a change will affect several platforms so I'm
> currently just
> raising the issue as I want to know if it's a good idea before
> starting work on it.
> 

We do have partial support for this on Intel platforms but we also have
the side channel of using other shared IO areas for panic information.

> Also, does this qualify as a minor ABI bump?

Yes.

I would also go further here and invoke a polling GDB stuff (Kconfig
option - with all IRQs OFF) after the panic IPC. This way the user
could connect GDB for further debug.

Liam
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