Re: [RFC PATCHv2 1/4] drivers/otp: add initial support for OTP memory

Jamie Iles
2011-03-26T02:40:16Z

On Fri, Mar 25, 2011 at 10:16:48PM -0400, Mike Frysinger wrote:
> On Fri, Mar 25, 2011 at 20:21, Jamie Iles wrote:
> > For the actual ioctl() we should assume byte addressing rather than
> > words though and do the conversion in the driver so we can cope with
> > devices that don't have 64-bit words and do the locking on a looping
> > word-by-word basis.
> >
> >        struct otp_lock_req {
> >                __u32   start_addr;
> >                __u32   byte_count;
> >        };
>
> i would add an ABI field here too so if in the future we want to add
> stuff, we can do so without adding new ioctls. like "u16 version; u16
> flags;". then in the ioctl, if version isnt 0, we return ENOTSUP. in
> the future, we can add flags or bump the version.

Sounds like a good idea.

> > Mike, would this be OK with you if we used a different ioctl() to the
> > one bfin-otp is using currently?  I notice that it's using the OTPLOCK
> > ioctl() from MTD but I think it's using the argument in a different way.
>
> i re-used OTPLOCK because it's exactly the name i wanted and it was
> easier than carving out my own namespace, but the args are different.
> i can see how people might find this undesirable.

OK, well seeing as we're making this generic we may as well reserve a
range of ioctls. I'll reserve a few of them and add OTP_LOCK_AREA for
now.

Jamie