> -----Original Message----- > From: Alexander Graf [mailto:ag...@suse.de] > Sent: Friday, September 19, 2014 3:33 PM > To: Phillips Kim-R1AAHA; Yoder Stuart-B08248 > Cc: Rivera Jose-B46482; <gre...@linuxfoundation.org>; <a...@arndb.de>; > <linux-kernel@vger.kernel.org>; Wood > Scott-B07421; <linuxppc-rele...@linux.freescale.net> > Subject: Re: [PATCH 1/4] drivers/bus: Added Freescale Management Complex APIs > > > > On 19.09.14 22:24, Kim Phillips wrote: > > On Fri, 19 Sep 2014 14:06:32 -0500 > > Yoder Stuart-B08248 <stuart.yo...@freescale.com> wrote: > > > >>>>>>>>> +/** > >>>>>>>>> + * @brief Management Complex firmware version information > >>>>>>>>> + */ > >>>>>>>>> +#define MC_VER_MAJOR 2 > >>>>>>>>> +#define MC_VER_MINOR 0 > >>>>>>>> > >>>>>>>> code should be adjusted to run on all *compatible* versions of h/w, > >>>>>>>> not strictly the one set in these defines. > >>>>>>> This comment is not precise enough be actionable. > >>>>>>> What exactly you want to be changed here? > >>>>>> > >>>>>> I think the easy thing to do is to convert the exact version check > >>>>>> into a ranged version check: have > >>> minimum and maximum versions you support. Or a list of exact versions you > >>> support. Or not check for the > >>> version at all - or only for the major version and guarantee that the > >>> major version indicates backwards > >>> compatibility. > >>>>> > >>>>> yes, this was my point: elsewhere I noticed the code denies to run > >>>>> iff those defines are not matched exactly: that code should change > >>>>> to run as Alex describes. > >>>>> > >>>> As I mentioned in the reply to Alex, I will remove the minor version > >>>> check. > >>> > >>> the code should be able to run on all subsequent versions of the > >>> h/w, even in the major version case. > >> > >> You're right, in the future if there are future major versions we would > >> want this > >> same driver to function on multiple versions of the hardware. But at this > >> point in time we don't know what future evolutions there will be and we > >> need the check to error out for now. > > > > why? We have to make the standard assumption that newer versions > > will be backward compatible, in which case the driver should be left > > to run. > > How much is the interface set in stone?
It is set in stone, in that a particular version has an specific set of commands. > Can we indicate to the MC that > we want version x of the protocol? Then the MC can tell us whether it's > compatible or not. No, it's not that clever. For the DPRC object there is a set of commands with a binary interface. The major/minor version number tell us what version of the hw object we are dealing with...what commands are there, what version of the binary interface is there. Stuart -- 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/
