sbefifo userspace api

[Jeremy Kerr]

Hi Brad,

> Looking to start a discussion around possible user space and kernel
> APIs for the POWER9 sbefifo driver.
> 
> There exists today an “alternate" sbefifo driver :-) that provides a
> single submit ioctl.  Applications submit a request and get a reply in
> single system call.
> 
> Is something like that the best approach for an upstream driver?  Or
> should we try something more "pipe like" with read/write interfaces?

It probably depends on the functionality there; ioctl() is useful in
that (as you say) we can handle request and response in a single
syscall, read() / write() may be more appropriate if ordering can be
handled in userspace.

Can you add a little description about the functionality we're exposing?
That may suggest a particular API.

> Would the in-kernel API be the same as the user space API?

Probably not :)

Cheers,


Jeremy