Hi Rob,
On 2/25/20 8:57 PM, Rob Herring wrote:
On Fri, Feb 21, 2020 at 1:48 PM Lukasz Luba lukasz.luba@arm.com wrote:
Add device to the Energy Model framework. It will create a dedicated and unified data structures used i.e. in the thermal framework. The power model used in dev_pm_opp subsystem is simplified and created based on DT 'dynamic-power-coefficient', volatage and frequency. It is
typo.
I'll fix it.
similar to the CPU model used in Energy Aware Scheduler.
Signed-off-by: Lukasz Luba lukasz.luba@arm.com
drivers/gpu/drm/panfrost/panfrost_devfreq.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/panfrost/panfrost_devfreq.c b/drivers/gpu/drm/panfrost/panfrost_devfreq.c index 413987038fbf..d527a5113950 100644 --- a/drivers/gpu/drm/panfrost/panfrost_devfreq.c +++ b/drivers/gpu/drm/panfrost/panfrost_devfreq.c @@ -105,6 +105,8 @@ int panfrost_devfreq_init(struct panfrost_device *pfdev) } pfdev->devfreq.devfreq = devfreq;
dev_pm_opp_of_register_em(dev, NULL);Can't fail?
Yes, it can fail but the function does not return anything. It can easily fail, it's looking for "dynamic-power-coefficient" in the device node. The DT binding for the devfreq devices would also be good to add..
I would have to probably change it into returning 'int' and modify all old cpufreq drivers.
cooling = of_devfreq_cooling_register(dev->of_node, devfreq); if (IS_ERR(cooling)) DRM_DEV_INFO(dev, "Failed to register cooling device\n");@@ -118,6 +120,7 @@ void panfrost_devfreq_fini(struct panfrost_device *pfdev) { if (pfdev->devfreq.cooling) devfreq_cooling_unregister(pfdev->devfreq.cooling);
dev_pm_opp_of_unregister_em(&pfdev->pdev->dev); dev_pm_opp_of_remove_table(&pfdev->pdev->dev);Does it make sense to keep this (and the registration side) as separate calls? Perhaps there's some ordering requirement with everything between dev_pm_opp_of_add_table() and dev_pm_opp_of_register_em()?
Yes, dev_pm_opp_of_register_em() uses em_data_callback which operates on OPPs to calculate power values and costs, so the the OPP table should be already there.
While you're just adding 2 lines, it seems there's a lot of complexity exposed to the driver just to initialize devfreq/opp.
It depends, for example devfreq devices like buses would likely never use the energy model. Potential clients would be GPUs, DSPs, ISPs.
Could you help me with defining a DT binding for this "dynamic-power-coefficient" entry? It could be used in different types of devices. Should it be placed in each of these devices documentation file, or in some one common file?
Thank you for your comments.
Regards, Lukasz