Hi Kevin,
On 05/31/2012 03:42 PM, Kevin Hilman wrote:
> Jon Hunter <[email protected]> writes:
>
>> Hi Kevin, Will,
>>
>> On 05/30/2012 08:29 PM, Will Deacon wrote:
>>> Hi Kevin,
>>>
>>> On Wed, May 30, 2012 at 10:50:01PM +0100, Kevin Hilman wrote:
>>>> Basically, I don't like the result when we have to hack around missing
>>>> runtime PM support for a driver, so IMO, the driver should be updated.
>>>>
>>>> IOW, it looks to me like the armpmu driver should grow runtime PM
>>>> support. The current armpmu_release|reserve should probably be replaced
>>>> with runtime PM get/put, and the functionality in those functions would
>>>> be the runtime PM callbacks instead.
>>>>
>>>> Will, any objections to armpmu growing runtime PM support?
>>>
>>> My plan for the armpmu reservation is to kill the global reservation scheme
>>> that we currently have and push those function pointers into the arm_pmu,
>>> so that fits with what you'd like.
>>>
>>> The only concern I have is that we need the mutual exclusion even when we
>>> don't have support for runtime PM. If we can solve that then I'm fine with
>>> the approach.
>>
>> To add a bit more food for thought, I had implemented a quick patch to
>> add runtime PM support for PMU. You will notice that I have been
>> conservative on where I have placed the pm_runtime_get/put calls,
>> because I am not too familiar with the PMU driver to know exactly
>> where we need to maintain the PMU context. So right now these are just
>> around the reserve_hardware/release_hardware calls. This works on OMAP
>> for some quick testing. However, I would need to make sure this does
>> not break compilation without runtime PM enabled.
>>
>> Let me know your thoughts.
>
> That looks good, but I'm curious what would be done in the new
> plat->runtime_* hooks. Maybe the irq enable/disable stuff in the pmu
> driver needs to be moved into the runtime PM hooks?
For omap4, the plat->runtime_* hooks look like ...
+static int omap4_pmu_runtime_resume(struct device *dev)
+{
+ /* configure CTI0 for PMU IRQ routing */
+ cti_unlock(&omap4_cti[0]);
+ cti_map_trigger(&omap4_cti[0], 1, 6, 2);
+ cti_enable(&omap4_cti[0]);
+
+ /* configure CTI1 for PMU IRQ routing */
+ cti_unlock(&omap4_cti[1]);
+ cti_map_trigger(&omap4_cti[1], 1, 6, 3);
+ cti_enable(&omap4_cti[1]);
+
+ return 0;
+}
+
+static int omap4_pmu_runtime_suspend(struct device *dev)
+{
+ cti_disable(&omap4_cti[0]);
+ cti_disable(&omap4_cti[1]);
+
+ return 0;
+}
This is what I have implemented so far and currently testing. So really
just using the hooks to configure the cross triggering interface.
Is this what you were thinking?
Cheers
Jon
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