[PATCH v10 1/3] ipmi: ssif_bmc: Add SSIF BMC driver

[Graeme Gregory <quic_ggregory@quicinc.com>]

On Mon, Oct 10, 2022 at 12:08:24PM +0100, Graeme Gregory wrote:
> 
> On 10/10/2022 02:28, Quan Nguyen wrote:
> > 
> > 
> > On 07/10/2022 20:26, Graeme Gregory wrote:
> > >
> > > On 04/10/2022 10:31, Quan Nguyen wrote:
> > > > The SMBus system interface (SSIF) IPMI BMC driver can be used to
> > > > perform
> > > > in-band IPMI communication with their host in management (BMC) side.
> > > >
> > > > Thanks Dan for the copy_from_user() fix in the link below.
> > > >
> > > > Link: https://lore.kernel.org/linux-arm-kernel/20220310114119.13736-4-quan at os.amperecomputing.com/
> > > > Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
> > >
> > > I have been testing this on our hardware and I don't seem to be able
> > > to get this driver working. I was using an older version.
> > >
> > > I have hacked ssifbridged to deal with the change in len from u8 to
> > > unsigned int.
> > >
> > > It works as long as I only ever send SSIF commands, any attempt to
> > > read a response crashes the state machine and the driver never
> > > recovers. No further SSIF comms is possible! (slave doesnt even ACK
> > > writes).
> > >
> > > A couple of comments below on possible state machine errors.
> > >
> > > Its possible I am doing something wrong!
> > >
> >
> > Thanks Graeme for the test and the comments.
> >
> > What's your testing hardware?
> >
> > This was tested with Aspeed ast2500 and ast2600 with the patch series
> > [1] below applied.
> >
> > If you use the same hw, could you pick the series and see if any thing
> > improve ?
> >
> > [1] https://lore.kernel.org/all/20210616031046.2317-1-quan at os.amperecomputing.com/
> >
> Thanks, that patch series does stop the state machine crashing.
>
> I am testing on AST2600EVB with A1 rev, but we also have our own DC-SCM with
> A3 chip.
>
> Responses are still not working for me, but I think that may be an error in
> my ssifbridged hacks.
>
> Oct 10 10:54:55 qcom-evb-proto-ccf37d18ea0c ssifbridged[335]: Read ssif
> request message with len=13 netfn=44 lun=0 cmd=2
>
> Oct 10 10:54:55 qcom-evb-proto-ccf37d18ea0c ipmid[312]: BootCode:
> 000000000000000000
>
> Oct 10 10:54:55 qcom-evb-proto-ccf37d18ea0c ssifbridged[335]: Send ssif
> respond message with len=4 netfn=45 lun=0 cmd=2 cc=0
>
> Oct 10 10:54:55 qcom-evb-proto-ccf37d18ea0c kernel: ipmi-ssif-host 0-0010:
> Warn: on_read_requested_event unexpected READ REQUESTED in state=SSIF_READY
>
> Oct 10 10:54:55 qcom-evb-proto-ccf37d18ea0c kernel: ipmi-ssif-host 0-0010:
> Warn: on_stop_event unexpected SLAVE STOP in state=SSIF_ABORTING
>
Just to close the loop on this, I have now fully tested this driver on
our setup internally.

Final hitch turned out to be an aardvark not issuing STOP events between
reads/writes.

Thanks for the work.

Graeme