[PATCH v2 1/2] powerpc/mpic: Add Open-PIC global timer document
Scott Wood
scottwood at freescale.com
Wed Aug 15 07:18:40 EST 2012
On 08/13/2012 09:40 PM, Wang Dongsheng-B40534 wrote:
>>>> +Example 2:
>>>>> +
>>>>> + timer: timer at 010f0 {
>>>>> + compatible = "open-pic,global-timer";
>>>>> + device_type = "open-pic";
>>>>> + reg = <0x010f0 4 0x01100 0x100>;
>>>>> + interrupts = <0 0 3 0
>>>>> + 1 0 3 0
>>>>> + 2 0 3 0
>>>>> + 3 0 3 0>;
>>>>> + };
>>>>
>>>> 4-cell interrupt specifiers are specific to Freescale MPICs. This
>>>> means there's no way to describe the timer interrupt on a non-
>> Freescale openpic.
>>>> Again, I suggest we not bother with this in the absence of an actual
>>>> need to support the timer on non-Freescale openpic in partitioned
>> scenarios.
>>>> The existing openpic node is sufficient to describe the
>>>> hardware in the absence of partitioning. We could have an
>>>> "openpic-no-timer" property to indicate that we're describing it
>>>> separately, so that the absence of a timer node isn't ambiguous as to
>>>> whether it's an old tree or a partitioned scenario. An fsl,mpic
>>>> compatible would imply openpic-no-timer.
>>>>
>>>> Note that I believe many of the non-Freescale openpic nodes are going
>>>> to be found on systems with real Open Firmware, so we can't go
>>>> changing the device tree for them.
>>> [Wang Dongsheng] In the Open-PIC specification, there are four timer.
>>> interrupts = <0 0 3 0
>>> 1 0 3 0
>>> 2 0 3 0
>>> 3 0 3 0>;
>>>
>>> The "interrupts" just let user know there are four timers. Usage based
>> "interrupts"
>>> binding to change dts.
>>
>> I can't understand the above or how it's a response to what I wrote.
>>
> [Wang Dongsheng] I mean this just to tell how many timers to support in Open-PIC
> specification. If someone needs to write "interrupts" into dts, this must comply
> with the specification of the interrupt to write. this is based on the pic driver
> should be changed in different platforms.
My point (beyond that examples provided should be valid for *some*
system) is there is no valid thing to put in the interrupts property
here when the interrupt controller is not "fsl,mpic", so this doesn't work.
-Scott
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