[Skiboot] [PATCH] hw/port80: Squash No SYNC error

[Andrew Jeffery]

On Fri, 18 Oct 2019, at 15:00, Oliver O'Halloran wrote:
> On Aspeed BMCs can be configured to route LPC IO address 0x80 to a GPIO
> port. Some systems use this to implement a boot progress indicator, but
> not all of them.
> 
> There's no easy way to tell if this has been setup or not and if it
> hasn't we get an LPC SYNC no-response error from out LPC master. When we
> reach Linux and enable interrupts this results in this spurious error
> being printed:
> 
>     LPC[000]: Got SYNC no-response error. Error address reg: 0xd0010082
> 
> lpc_probe_write() is intended to catch situations where the peripherial
> being written to might not be configured, so use that instead of
> lpc_outb() to squash the error.
> 
> Cc: Ranga <stewart at flamingspork.com>
> Cc: Andrew Jeffery <andrew at aj.id.au>
> Signed-off-by: Oliver O'Halloran <oohall at gmail.com>
> ---
> Stewart, do you know what systems actually implment this feature?
> Seem like you added op_display_lpc() to add the BMC systems, but
> I'm guessing only a few of them actually support it.

At least the Raptor systems as far as I'm aware, they needed some way
to observe boot progress.

Anyway, patch seems reasonable to me.

Acked-by: Andrew Jeffery <andrew at aj.id.au>