On Wed, Sep 21, 2016 at 10:02:47AM -0400, Tom Rini wrote:
On Wed, Sep 21, 2016 at 03:46:08PM +0200, Enric Balletbo Serra wrote:
2016-09-21 14:51 GMT+02:00 Tom Rini trini@konsulko.com:
On Wed, Sep 21, 2016 at 01:46:51PM +0200, Enric Balletbo Serra wrote:
Hi,
2016-09-21 11:39 GMT+02:00 Ladislav Michl ladis@linux-mips.org:
On Tue, Sep 20, 2016 at 08:26:36PM -0400, Tom Rini wrote:
On Wed, Sep 21, 2016 at 01:52:21AM +0200, Ladislav Michl wrote: > On Tue, Sep 20, 2016 at 07:45:14PM -0400, Tom Rini wrote:
[snip]
> > But why do we even need to set MACH_TYPE these days? > > That's only needed for non-device tree kernel boot. These boards run mostly > vendor provided kernels based on TI 2.6.32 or 2.6.37 kernel tree with > daughter boards specific patches on top of it. Enric is concerned not > to break that support, so I'm trying to keep it.
OK, if you're still supporting stuff that old then yes, it makes sense. And we can't get this right at run time?
I asked several times, if there's a way to differentiate those boards (0020, 0030 and 0032) at runtime, but never get an answer. Of course I'd like to see one U-Boot binary to rule them all, but I'm out of clue there. Few people added to Cc...
There is no way to differentiate those boards at runtime, those boards are completely different platforms that share same processor, like BeagleBoard or OMAP3 Overos . For me what you're trying to do is join different platforms with the same processor, so why not join BeagleBone, Overos, and IGEPs and all other OMAP3 based platforms?
Note that the different beagleboard used GPIOs to tell which platform is which :)
Yes, but if I'm not mistaken you have different GPIOs for different hardware revisions of Beagleboard. For IGEPv2 this is also true, you have different GPIOs for different hardware revisions of IGEPv2. But we're talking about join two completely different boards, i.e join IGEPv2 (IGEP0020) with IGEP COM PROTON (IGEP0032) would be similar to join Beagleboard with OMAP3 OVERO COM.
Well, on igep platform MACH_TYPE is currently used for: - mux configuration (with IGEP COM PROTON strangely left out) - status LED configuration I wouldn't say these are completely different boards, at lest from software perspective.
OTOH I think the Ladis work trying to join the IGEP boards is really interesting, just want to look deeper :)
Right. To play the thought exercise out a bit farther, if all of the detection methods for Beagleboard would _not_ cause an OVERO COM to be identified as a Beagle, we could move on to trying to see what rev overo we're on, or just assume it's that if all else fails. Is anything like that possible with these IGEP boards?
I certainly didn't mean any board detection method hardware designer had in mind while drawing schemantics, but more likely something like this: IGEPv2 is using GPIO_94 to drive WIFI_PD_n and there's 100K pullup, so setting this pin as input and reading its value could give some clue. Now question is if there's such a combination of gpios used over this board family, which provides reliable detection method. Unfortunately, I have only IGEPv2 and public schemantics is available only for this board.
Another approach might be to configure U-Boot using FDT and translate that information into MACH_TYPE and kernel command line to support non-device tree enabled kernels.
And to be clear over on this part, if we can tell at run time (or normal build time even, without directly passing MACH_TYPE=..) we should set that then instead of SYS_EXTRA_OPTIONS.
ladis