[Skiboot] [PATCH V2] Add OPAL_CONSOLE_FLUSH to the OPAL API

[Stewart Smith]

Russell Currey <ruscur at russell.cc> writes:

> uart consoles only flush output when polled.  The Linux kernel calls
> these pollers frequently, except when in a panic state.  As such, panic
> messages are not fully printed unless the system is configured to reboot
> after panic.
>
> This patch adds a new call to the OPAL API to flush the buffer.  If the
> system has a uart console (i.e. BMC machines), it will incrementally
> flush the buffer, returning if there is more to be flushed or not.  If
> the system has a different console, the function will have no effect.
> This will allow the Linux kernel to ensure that panic message have been
> fully printed out.
>
> The existing synchronous flushing mechanism used in OPAL's shutdown and
> reboot routines has been refactored into a helper that repeatedly calls
> the new partial flush function.
>
> Signed-off-by: Russell Currey <ruscur at russell.cc>
> ---
> Changes since V1:
>  - Refactored into a partial flush instead of a full synchronous flush
>  - Added different return values based on the status
>  - Change the synchronous flushing function to use the new call
>
> This patch is dependent on being merged before the PCI hotplug patches,
> which also add a new OPAL API call, incrementing OPAL_LAST.
>
> This should eventually head towards stable, maybe only after the kernel
> patch that uses it gets merged?

Thanks!

Merged to stable as of f2efc65 and master as of 0890821.

Note that we still need the kernel patch to match this.


-- 
Stewart Smith
OPAL Architect, IBM.