Users of SBE FIFO kernel driver

[Alistair Popple]

On Thu, 2 Feb 2017 01:59:08 PM Joel Stanley wrote:
> Hi Chris,
> 
> On Thu, Feb 2, 2017 at 5:58 AM, Christopher Bostic
> <cbostic at linux.vnet.ibm.com> wrote:
> > I've not seen this discussed in the group but if this has already been
> > determined than any pointers to the latest documentation would be
> > appreciated.
> >
> > Who are all the potential users of the OpenBMC SBE FIFO device driver?   I
> > understand it will need to export its general submit interface to other
> > kernel drivers.  Only one I know of for sure would be the OCC driver Eddie
> > James is working on.
> 
> In addition to Eddie's driver, in userspace we will have the code that
> performs the power on sequence.
> 
> > Any others?
> > What about user space access of the SBE FIFO engine?  What apps would
> > require it?  Cronus I assume will need some means to directly access it.
> 
> We want userspace API and an in-kernel API.

Yep. For example as Ben mentioned the chip-ops also use the SBE FIFO. However 
we certainly don't want to put chip-ops directly in the kernel. It makes more 
sense to use a userspace SBE FIFO API to do the chips-ops, power on sequence 
etc. from userspace.
 
> The driver you design will need to take into account that there will
> be multiple users from each of these APIs. For instance, there will be
> Eddie's OCC hwmon driver and the userspace code that kicks off the
> boot sequence.
> 
> Cheers,
> 
> Joel