On Wed, May 11, 2016 at 11:16 AM, Jon Hunter <jonathanh@xxxxxxxxxx> wrote: > > On 11/05/16 17:08, Jon Hunter wrote: >> Hi Rob, >> >> On 11/05/16 16:51, Rob Herring wrote: >>> On Sat, May 7, 2016 at 9:10 AM, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote: >>>> Hi Jon, >>>> >>>> On Fri, May 6, 2016 at 10:32 AM, Jon Hunter <jonathanh@xxxxxxxxxx> wrote: >>>>>> The "nvidia,tegra210-agic" string can be taken as describing any >>>>>> Tegra-210 specific integration quirks, though I agree that's also not >>>>>> fantastic for extending PM support beyond Tegra 210 and variants >>>>>> thereof. >>>>>> >>>>>> So maybe the best approach is bailing out in the presence of clocks >>>>>> and/or power domains after all, on the assumption that nothing today has >>>>>> those properties, though I fear we may have problems with that later >>>>>> down the line if/when people describe those for the root GIC to describe >>>>>> those must be hogged, even if not explicitly managed. >>>>> >>>>> On further testing, by bailing out in the presence of clocks and/or >>>>> power-domains, the problem I now see is that although the primary gic-400 >>>>> has been registered, we still try to probe it again later as it matches >>>>> the platform driver. One way to avoid this would be ... >>>>> >>>>> diff --git a/drivers/of/irq.c b/drivers/of/irq.c >>>>> index e7bfc175b8e1..631da7ad0dbf 100644 >>>>> --- a/drivers/of/irq.c >>>>> +++ b/drivers/of/irq.c >>>>> @@ -556,6 +556,8 @@ void __init of_irq_init(const struct of_device_id *matches) >>>>> * its children can get processed in a subsequent pass. >>>>> */ >>>>> list_add_tail(&desc->list, &intc_parent_list); >>>>> + >>>>> + of_node_set_flag(desc->dev, OF_POPULATED); >>>>> } >>>> >>>> That sounds like the right thing to do to me... >>> >>> Seems fine to me, but it would be a problem since this is a global >>> decision if you wanted to have some hand-off from an "early driver" to >>> a platform driver. I guess setting the flag could move to drivers that >>> need it although I don't think drivers should be touching the flags. >> >> Isn't this the other way around? Setting this flag means that I have >> been populated and so don't bother creating a platform device for this >> device as it isn't needed. A by-product if this, is that if we did >> happen to have a platform driver for the irqchip that also has an early >> driver, then the hand-off would never happen if the early init was >> successful. >> >> The driver would still have to decide whether to hand-off and to do that >> it would need to return an error from the early driver [0]. >> >>>>> If this is not appropriate then I guess I will just need to use >>>>> "tegra210-agic" for the compatibility flag. >>>> >>>> As I want this for plain gic-400, I'd be unhappy ;-) >>> >>> IMO, the plain gic-400 should not have these dependencies and you >>> should use SoC specific compatible strings should you need to deal >>> with this problem. >> >> It is fine for my case, but it does mean I cannot say ... >> >> compatible = "tegra210-agic", "gic-400"; >> >> ... because this will always match the early driver (unless we do >> something like I have suggested above). So I would have ... > > Sorry this is wrong. The above will always match the early driver. > > The problem with the above compatibility string is that, if the platform > driver matches "gic-400" then it will try to probe all gic-400s even if > they have been initialised early and this is definitely not what we > want. This could be solved by setting the OF_POPULATED flag. A platform driver for just gic-400 is wrong IMO until we have platform drivers for all interrupt controllers. Another reason to set OF_POPULATED flag is we are needlessly creating platform devices for irq controllers that will never have platform drivers. So I'd go with that approach. Rob -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
