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OPP: Use _set_opp_level() for single genpd case

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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: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
This commit is contained in:
Viresh Kumar 2023-10-12 15:45:21 +05:30
parent 073d3d2ca7
commit 6d366d0e54
2 changed files with 32 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/opp/core.c
View File

@ -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;

31
drivers/opp/of.c
View File

@ -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;
}