On Monday 11 February 2013, Samuel Ortiz wrote: > On Mon, Feb 11, 2013 at 11:52:42AM +0000, Arnd Bergmann wrote: > > On Thursday 07 February 2013, Samuel Ortiz wrote: > > > On Thu, Feb 07, 2013 at 10:34:44PM +0000, Arnd Bergmann wrote: > > > > On Thursday 07 February 2013, Tomas Winkler wrote: > > > > > + > > > > > +struct mei_bus_ops { > > > > > + int (*send)(struct mei_bus_client *client, u8 *buf, size_t > > > > > length); > > > > > + int (*recv)(struct mei_bus_client *client, u8 *buf, size_t > > > > > length); > > > > > +}; > > > > > + > > > > > > > > Can you have more than one set of mei_bus_ops in a driver? > > > You can have at most one mei_bus_ops per mei_bus_client. > > > > > > > If not, how about adding the callbacks to the mei_bus_driver structure > > > > directly as a simplification? > > > I can add the ops directly to the mei_bus_client structure, yes. > > > > I looked at the new version, and it's not what I assumed it would be. > > I thought the operations were specific to a client driver and should > > be part of the /mei_bus_driver/ structure, not the /mei_bus_client/. > The ops should be part of mei_bus_client as they're specific to the MEI > protocol for a given IP block on the ME. You need to have MEI and HECI > knowledge to implement those ops and drivers (defining their mei_bus_driver > structure) should not have that kind of knowledge but rather focus on the > technology they're driving. > If we take the NFC example again, the drivers/nfc/ code will send NFC payloads > to the bus I/O routines and this is where the mei_bus_client ops will add the > ME specific protocol (command and request id for the NFC block) on top of it. > In practice, this is an additional header which handles a transport layer > that's > specific not only to the ME but to the NFC block of it. So each ME block can > have its own protocol to send and receive technology specific payloads, that's > what those ops implement. > That's why I think that those ops should not be defined by the drivers/nfc/ > code > and in fact should be opaque to it.
I think I'm still confused. What I read in your description is that unlike other subsystems that have a common bus implementation that is hooked into by two kinds of drivers (bus drivers that provide devices like a USB host controller, and device drivers that use those devices), you have three components that can be mixed independently: the bus (based on which PCI device you have), the transport and the endpoint device. Is that correct? If so, how do you know which transport to use? Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/