Commit 6d366d0e authored by Viresh Kumar's avatar Viresh Kumar
Browse files

OPP: Use _set_opp_level() for single genpd case 



There are two genpd (as required-opp) cases that we need to handle,
devices with a single genpd and ones with multiple genpds.

The multiple genpds case is clear, where the OPP core calls
dev_pm_domain_attach_by_name() for them and uses the virtual devices
returned by this helper to call dev_pm_domain_set_performance_state()
later to change the performance state.

The single genpd case however requires special handling as we need to
use the same `dev` structure (instead of a virtual one provided by genpd
core) for setting the performance state via
dev_pm_domain_set_performance_state().

As we move towards more generic code to take care of the required OPPs,
where we will recursively call dev_pm_opp_set_opp() for all the required
OPPs, the above special case becomes a problem.

It doesn't make sense for a device's DT entry to have both "opp-level"
and single "required-opps" entry pointing to a genpd's OPP, as that
would make the OPP core call dev_pm_domain_set_performance_state() for
two different values for the same device structure. And so we can reuse
the 'opp->level" field in such a case and call _set_opp_level() for the
device.

Reviewed-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Tested-by: default avatarStephan Gerhold <stephan.gerhold@kernkonzept.com>
Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
parent 073d3d2c

drivers/opp/core.c

+4 −2
Original line number Diff line number Diff line
@@ -1088,10 +1088,12 @@ static int _opp_set_required_opps_generic(struct device *dev, 
static int _opp_set_required_opps_genpd(struct device *dev,

	struct opp_table *opp_table, struct dev_pm_opp *opp, bool scaling_down)

{

	struct device **genpd_virt_devs =

		opp_table->genpd_virt_devs ? opp_table->genpd_virt_devs : &dev;

	struct device **genpd_virt_devs = opp_table->genpd_virt_devs;

	int index, target, delta, ret;



	if (!genpd_virt_devs)

		return 0;



	/* Scaling up? Set required OPPs in normal order, else reverse */

	if (!scaling_down) {

		index = 0;

drivers/opp/of.c

+28 −3
Original line number Diff line number Diff line
@@ -296,7 +296,7 @@ void _of_clear_opp(struct opp_table *opp_table, struct dev_pm_opp *opp) 
	of_node_put(opp->np);

}



static int _link_required_opps(struct dev_pm_opp *opp,

static int _link_required_opps(struct dev_pm_opp *opp, struct opp_table *opp_table,

			       struct opp_table *required_table, int index)

{

	struct device_node *np;
@@ -314,6 +314,31 @@ static int _link_required_opps(struct dev_pm_opp *opp, 
		return -ENODEV;

	}



	/*

	 * There are two genpd (as required-opp) cases that we need to handle,

	 * devices with a single genpd and ones with multiple genpds.

	 *

	 * The single genpd case requires special handling as we need to use the

	 * same `dev` structure (instead of a virtual one provided by genpd

	 * core) for setting the performance state.

	 *

	 * It doesn't make sense for a device's DT entry to have both

	 * "opp-level" and single "required-opps" entry pointing to a genpd's

	 * OPP, as that would make the OPP core call

	 * dev_pm_domain_set_performance_state() for two different values for

	 * the same device structure. Lets treat single genpd configuration as a

	 * case where the OPP's level is directly available without required-opp

	 * link in the DT.

	 *

	 * Just update the `level` with the right value, which

	 * dev_pm_opp_set_opp() will take care of in the normal path itself.

	 */

	if (required_table->is_genpd && opp_table->required_opp_count == 1 &&

	    !opp_table->genpd_virt_devs) {

		if (!WARN_ON(opp->level != OPP_LEVEL_UNSET))

			opp->level = opp->required_opps[0]->level;

	}



	return 0;

}
@@ -338,7 +363,7 @@ static int _of_opp_alloc_required_opps(struct opp_table *opp_table, 
		if (IS_ERR_OR_NULL(required_table))

			continue;



		ret = _link_required_opps(opp, required_table, i);

		ret = _link_required_opps(opp, opp_table, required_table, i);

		if (ret)

			goto free_required_opps;

	}
@@ -359,7 +384,7 @@ static int lazy_link_required_opps(struct opp_table *opp_table, 
	int ret;



	list_for_each_entry(opp, &opp_table->opp_list, node) {

		ret = _link_required_opps(opp, new_table, index);

		ret = _link_required_opps(opp, opp_table, new_table, index);

		if (ret)

			return ret;

	}