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Message-ID: <CAJuYYwRxCTWxnof1HUqYVX4mbzWCxcab69CJyKxOh13bQbQ_5Q@mail.gmail.com>
Date: Mon, 26 Mar 2012 21:06:28 +0530
From: Thomas Abraham <thomas.abraham@...aro.org>
To: Rob Herring <robherring2@...il.com>
Cc: devicetree-discuss@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
linux-samsung-soc@...r.kernel.org, rob.herring@...xeda.com,
patches@...aro.org
Subject: Re: [PATCH] of/irq: of_irq_init: Call initialization function for all controllers
On 26 March 2012 18:34, Rob Herring <robherring2@...il.com> wrote:
> On 03/25/2012 11:16 AM, Thomas Abraham wrote:
>> On 25 March 2012 20:50, Rob Herring <robherring2@...il.com> wrote:
>>> On 03/25/2012 07:38 AM, Thomas Abraham wrote:
>>>> The of_irq_init function stops processing the interrupt controller hierarchy
>>>> when there are no more interrupt controller parents identified. Though this
>>>> condition suffices most cases, there are cases where a interrupt controller's
>>>> parent controller does not participate in the initialization of the interrupt
>>>> hierarchy. An example of such a case is the use of a interrupt nexus node
>>>> by a interrupt controller node which delivers interrupts to separate interrupt
>>>> parent controllers.
>>>>
>>>> Instead of stopping the processing of interrupt controller hierarchy in such
>>>> a case, the orphan interrupt controller node's descriptor can be identified
>>>> and its 'logical' parent in the descriptor is set as NULL. The processing of
>>>> interrupt hierarchy is then restarted by looking for descriptors which have
>>>> a NULL interrupt parent.
>>>>
>>>> Cc: Rob Herring <rob.herring@...xeda.com>
>>>> Cc: Grant Likely <grant.likely@...retlab.ca>
>>>> Signed-off-by: Thomas Abraham <thomas.abraham@...aro.org>
>>>> ---
>>>
>>> Wouldn't this accomplish the same thing? You just need to add the
>>> wakeup-map node name to your matches list.
>>>
>>>
>>> diff --git a/drivers/of/irq.c b/drivers/of/irq.c
>>> index 9cf0060..deeaf00 100644
>>> --- a/drivers/of/irq.c
>>> +++ b/drivers/of/irq.c
>>> @@ -416,8 +416,6 @@ void __init of_irq_init(const struct of_device_id
>>> *matches)
>>> INIT_LIST_HEAD(&intc_parent_list);
>>>
>>> for_each_matching_node(np, matches) {
>>> - if (!of_find_property(np, "interrupt-controller", NULL))
>>> - continue;
>>> /*
>>> * Here, we allocate and populate an intc_desc with the node
>>> * pointer, interrupt-parent device_node etc.
>>>
>>
>> Hi Rob,
>>
>> I tested with this, but the init function of wakeup controller is not
>> called. The following is the example nodes that I used for testing.
>>
>> gic:interrupt-controller@...90000 {
>> compatible = "arm,cortex-a9-gic";
>> #interrupt-cells = <3>;
>> #address-cells = <0>;
>> #size-cells = <0>;
>> interrupt-controller;
>> cpu-offset = <0x8000>;
>> reg = <0x10490000 0x1000>, <0x10480000 0x100>;
>> };
>>
>> combiner:interrupt-controller@...40000 {
>> compatible = "samsung,exynos4210-combiner";
>> #interrupt-cells = <2>;
>> interrupt-controller;
>> samsung,combiner-nr = <16>;
>> reg = <0x10440000 0x1000>;
>> interrupts = <0 0 0>, <0 1 0>, <0 2 0>, <0 3 0>,
>> <0 4 0>, <0 5 0>, <0 6 0>, <0 7 0>,
>> <0 8 0>, <0 9 0>, <0 10 0>, <0 11 0>,
>> <0 12 0>, <0 13 0>, <0 14 0>, <0 15 0>;
>> };
>>
>> wakeup_eint: interrupt-controller@...00000 {
>> compatible = "samsung,exynos5210-wakeup-eint";
>> reg = <0x11400000 0x1000>;
>> interrupt-controller;
>> #interrupt-cells = <2>;
>> interrupt-parent = <&wakeup_map>;
>> interrupts = <0x0 0>, <0x1 0>, <0x2 0>, <0x3 0>,
>> <0x4 0>, <0x5 0>, <0x6 0>, <0x7 0>,
>> <0x8 0>, <0x9 0>, <0xa 0>, <0xb 0>,
>> <0xc 0>, <0xd 0>, <0xe 0>, <0xf 0>,
>> <0x10 0>;
>>
>> wakeup_map: interrupt-map {
>> compatible = "samsung,exynos5210-wakeup-eint-map";
>> #interrupt-cells = <2>;
>> #address-cells = <0>;
>> #size-cells = <0>;
>> interrupt-map = <0x0 0 &gic 0 16 0>,
>> <0x1 0 &gic 0 17 0>,
>> <0x2 0 &gic 0 18 0>,
>> <0x3 0 &gic 0 19 1>,
>> <0x4 0 &gic 0 20 0>,
>> <0x5 0 &gic 0 21 1>,
>> <0x6 0 &gic 0 22 0>,
>> <0x7 0 &gic 0 23 1>,
>> <0x8 0 &gic 0 24 0>,
>> <0x9 0 &gic 0 25 1>,
>> <0xa 0 &gic 0 26 0>,
>> <0xb 0 &gic 0 27 1>,
>> <0xc 0 &gic 0 28 0>,
>> <0xd 0 &gic 0 29 1>,
>> <0xe 0 &gic 0 30 0>,
>> <0xf 0 &gic 0 31 1>,
>> <0x10 0 &combiner 2 4>;
>> };
>> };
>>
>> And following is the match table used for testing.
>>
>> static const struct of_device_id exynos4_dt_irq_match[] = {
>> { .compatible = "arm,cortex-a9-gic", .data = gic_of_init, },
>> { .compatible = "samsung,exynos4210-combiner",
>> .data = combiner_of_init, },
>> { .compatible = "samsung,exynos4210-wakeup-eint-map",
>
> Looks like you have a mismatch here: 5210 or 4210?
Sorry, that was a typo. I checked the code again. It is 4210.
>
>
>> .data = exynos_init_irq_eint, },
>> {},
>> };
>>
>> The ' interrupt-map' map sub-node of 'interrupt-controller@...00000'
>> node does not have a interrupt-parent property. So it inherits it from
>> its parent node, which is 'interrupt-map' itself. So the parent of
>> wakeup-map is not gic or combiner and hence the initialization
>> function of wakeup controller is not called.
>>
>
> That should be fine. If a node's interrupt-parent is itself, then that's
> treated as a root interrupt controller.
I checked this again and found that of_irq_find_parent() function when
called with pointer to "interrupt-map" node as the parameter, does not
return "interrupt-map" as the parent in the example nodes listed
above. This might be wrong and may be caused due to the check
of_get_property(p, "#interrupt-cells", NULL) == NULL
in the do..while loop in of_irq_find_parent() function. So this
explains why the 'interrupt-map' was not treated as the root interrupt
controller.
>
>> If a interrupt-parent property is added to 'interrupt-map' node (which
>> is probably not the right thing to do), and set the interrupt parent
>> as gic or combiner, there is a possibility that the interrupt-map is
>> initialized before the combiner (which is not correct since
>> interrupt-map uses combiner as one of its parents). But by placing
>> 'wakeup_eint' node ahead of combiner node, this can be overcome but
>> relying on placement of nodes in dts file is not a reliable solution.
>
> Your fix doesn't really guarantee the proper order either. It's still a
> side effect of the implementation. Perhaps a retry mechanism would work.
> Then the init for wakeup_eint can retry if the gic is not yet setup.
Ok. A retry mechanism would be most robust solution for this case.
Thanks,
Thomas.
[...]
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