[U-Boot] Update and Cut down mach types

Reinhard Meyer
2011-04-26T21:38:36Z

On 26.04.2011 23:32, Wolfgang Denk wrote:
> Dear Albert ARIBAUD,
>
> In message<4DB72D4A.5070102@aribaud.net> you wrote:
>>
>> Well, as you stated yourself recently, why would/should we maintain
>> mach-types that are apparently not going to be used? Do machine types
>> have other uses than for Linux? No code in U-Boot should worry about the
>> mach-id if not for Linux.
>
> Well, in principle you are of course right.
>
> But I am well aware that there is a ton of Linux BSPs out there which
> have never been pushed upstream into mainline by their respective
> creators for some reason or another. Also I see a chance that other
> uses of the mach-ids might exist - the Linux ARM folks have, fro a
> very long time, always explained what a clever idea this is to
> describe hardware features.
>
> I hesitate to cut off all these exitisting or even potential users
> lightly, when there is a solution that works reasonably well for them
> and, at the same time, brings only minimal maintenance burdon for us.
>
>> Also, if we still decide to maintain our own list of mach-types, we will
>> need some rule to decide when to remove mach-types from this special
>> list eventually. Otherwise, it'll become asymptotically identical to the
>> full lits that is also availabe, and then, what would be the point of
>> maintaining our own?
>
> That rule can be simple: we will only allow to add the now existing
> (in U-Boot mainline code) mach-ids, so this list should not grow
> further after the initial creation. OK, ther eis a slight chance that
> any newly added boards (to U-Boot) will get removed from the Linux
> master file later, but I consider this a small risk - especially as I
> expect to see more and ore device-tree based ARM ports quickly, so the
> whole mach-id thing becomes less and less of a pain.
>
>> So IMO, if we have mach-types in U-Boot for supporting Linux, then we
>> should keep using a (reasonably) up-to-date Linux machine ID list just
>> like we do now -- mach-types that disappear from the list mean Linux
>> support has become useless for that machine in U-Boot. And if we have
>> our own mach-type policy, different from "has linux support", then we
>> need to specify what this policy is and how it is implemented.
>
> I think we should be gentle to users of existing code and avoid
> breaking it. From now on, we could establish a policy that a mach-id
> can only be referenced when and as long mainline Linux support for
> this board exists.
>
> I'm open for suggestions.

Hi Wolfgang, Albert,

why don't we just create the #define MACH_xxx lines directly from the
"http://www.arm.linux.org.uk/developer/machines/download.php". We don't
need all the *_is_* macros in u-boot anyway. Then we would have just a few 1000
lines of #define MACH_*

Reinhard