Re: [Patch v5 4/6] soc: qcom: Extend RPMh power controller driver to register warming devices.

[Thara Gopinath <thara.gopinath@xxxxxxxxxx>]

On 3/27/20 6:53 PM, Bjorn Andersson wrote:
> On Thu 19 Mar 18:41 PDT 2020, Thara Gopinath wrote:
>
> > RPMh power control hosts power domains that can be used as
> > thermal warming devices. Register these power domains
> > with the generic power domain warming device thermal framework.
> >
> > Reviewed-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> > Signed-off-by: Thara Gopinath <thara.gopinath@xxxxxxxxxx>
> > ---
> >
> > v3->v4:
> > 	- Introduce a boolean value is_warming_dev in rpmhpd structure to
> > 	  indicate if a generic power domain can be used as a warming
> > 	  device or not.With this change, device tree no longer has to
> > 	  specify which power domain inside the rpmh power domain provider
> > 	  is a warming device.
> > 	- Move registering of warming devices into a late initcall to
> > 	  ensure that warming devices are registered after thermal
> > 	  framework is initialized.
>
> This information is lost when we merge patches, as such I would like
> such design decisions to be described in the commit message itself.
> But...
>
> >   drivers/soc/qcom/rpmhpd.c | 37 ++++++++++++++++++++++++++++++++++++-
> >   1 file changed, 36 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/soc/qcom/rpmhpd.c b/drivers/soc/qcom/rpmhpd.c
> > index 7142409a3b77..4e9c0bbb8826 100644
> > --- a/drivers/soc/qcom/rpmhpd.c
> > +++ b/drivers/soc/qcom/rpmhpd.c
> > @@ -11,6 +11,7 @@
> >   #include <linux/of_device.h>
> >   #include <linux/platform_device.h>
> >   #include <linux/pm_opp.h>
> > +#include <linux/pd_warming.h>
> >   #include <soc/qcom/cmd-db.h>
> >   #include <soc/qcom/rpmh.h>
> >   #include <dt-bindings/power/qcom-rpmpd.h>
> > @@ -48,6 +49,7 @@ struct rpmhpd {
> >   	bool		enabled;
> >   	const char	*res_name;
> >   	u32		addr;
> > +	bool		is_warming_dev;
> >   };
> >   
> >   struct rpmhpd_desc {
> > @@ -55,6 +57,8 @@ struct rpmhpd_desc {
> >   	size_t num_pds;
> >   };
> >   
> > +const struct rpmhpd_desc *global_desc;
> > +
> >   static DEFINE_MUTEX(rpmhpd_lock);
> >   
> >   /* SDM845 RPMH powerdomains */
> > @@ -89,6 +93,7 @@ static struct rpmhpd sdm845_mx = {
> >   	.pd = { .name = "mx", },
> >   	.peer = &sdm845_mx_ao,
> >   	.res_name = "mx.lvl",
> > +	.is_warming_dev = true,
> >   };
> >   
> >   static struct rpmhpd sdm845_mx_ao = {
> > @@ -452,7 +457,14 @@ static int rpmhpd_probe(struct platform_device *pdev)
> >   					       &rpmhpds[i]->pd);
> >   	}
> >   
> > -	return of_genpd_add_provider_onecell(pdev->dev.of_node, data);
> > +	ret = of_genpd_add_provider_onecell(pdev->dev.of_node, data);
> > +
> > +	if (ret)
> > +		return ret;
> > +
> > +	global_desc = desc;
> > +
> > +	return 0;
> >   }
> >   
> >   static struct platform_driver rpmhpd_driver = {
> > @@ -469,3 +481,26 @@ static int __init rpmhpd_init(void)
> >   	return platform_driver_register(&rpmhpd_driver);
> >   }
> >   core_initcall(rpmhpd_init);
> > +
> > +static int __init rpmhpd_init_warming_device(void)
> > +{
> > +	size_t num_pds;
> > +	struct rpmhpd **rpmhpds;
> > +	int i;
> > +
> > +	if (!global_desc)
> > +		return -EINVAL;
> > +
> > +	rpmhpds = global_desc->rpmhpds;
> > +	num_pds = global_desc->num_pds;
> > +
> > +	if (!of_find_property(rpmhpds[0]->dev->of_node, "#cooling-cells", NULL))
> > +		return 0;
> > +
> > +	for (i = 0; i < num_pds; i++)
> > +		if (rpmhpds[i]->is_warming_dev)
> > +			of_pd_warming_register(rpmhpds[i]->dev, i);
> > +
> > +	return 0;
> > +}
> > +late_initcall(rpmhpd_init_warming_device);
>
> ...why can't this be done in rpmhpd_probe()?
>
> In particular with the recent patches from John Stultz to allow rpmhpd
> to be built as a module I don't think there's any guarantees that
> rpmh_probe() will have succeeded before rpmhpd_init_warming_device()
> executes.

It is to take care of boot order.
So this has to happen after the thermal framework is initialized. 
Thermal framework is initialized with core_initcall. Can I move the 
rpmhpd init as a postcore_initcall ? Then I can get rid of this separate 
function and keep it as part of probe.

> Regards,
> Bjorn

--
Warm Regards
Thara