PM: domains: Support required OPPs in dev_pm_domain_attach_list()

JIRA: https://issues.redhat.com/browse/RHEL-81536

commit 98d277a
Author: Ulf Hansson <ulf.hansson@linaro.org>
Date: Thu, 10 Oct 2024 14:13:49 +0000

In the multiple PM domain case we need platform code to specify the index
of the corresponding required OPP in DT for a device, which is what
*_opp_attach_genpd() is there to help us with.

However, attaching a device to its PM domains is in general better done
with dev_pm_domain_attach_list(). To avoid having two different ways to
manage this and to prepare for the removal of *_opp_attach_genpd(), let's
extend dev_pm_domain_attach|detach_list() to manage the required OPPs too.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20241002122232.194245-5-ulf.hansson@linaro.org
Signed-off-by: Mark Langsdorf <mlangsdo@redhat.com>

Author: mlangsdorf

drivers/base/power/common.c

@@ -11,6 +11,7 @@
 #include <linux/pm_clock.h>
 #include <linux/acpi.h>
 #include <linux/pm_domain.h>
+#include <linux/pm_opp.h>
 
 #include "power.h"
 
@@ -222,13 +223,15 @@ int dev_pm_domain_attach_list(struct device *dev,
 	if (!pds)
 		return -ENOMEM;
 
-	size = sizeof(*pds->pd_devs) + sizeof(*pds->pd_links);
+	size = sizeof(*pds->pd_devs) + sizeof(*pds->pd_links) +
+	       sizeof(*pds->opp_tokens);
 	pds->pd_devs = kcalloc(num_pds, size, GFP_KERNEL);
 	if (!pds->pd_devs) {
 		ret = -ENOMEM;
 		goto free_pds;
 	}
 	pds->pd_links = (void *)(pds->pd_devs + num_pds);
+	pds->opp_tokens = (void *)(pds->pd_links + num_pds);
 
 	if (link_flags && pd_flags & PD_FLAG_DEV_LINK_ON)
 		link_flags |= DL_FLAG_RPM_ACTIVE;
@@ -244,6 +247,19 @@ int dev_pm_domain_attach_list(struct device *dev,
 			goto err_attach;
 		}
 
+		if (pd_flags & PD_FLAG_REQUIRED_OPP) {
+			struct dev_pm_opp_config config = {
+				.required_dev = pd_dev,
+				.required_dev_index = i,
+			};
+
+			ret = dev_pm_opp_set_config(dev, &config);
+			if (ret < 0)
+				goto err_link;
+
+			pds->opp_tokens[i] = ret;
+		}
+
 		if (link_flags) {
 			struct device_link *link;
 
@@ -264,9 +280,11 @@ int dev_pm_domain_attach_list(struct device *dev,
 	return num_pds;
 
 err_link:
+	dev_pm_opp_clear_config(pds->opp_tokens[i]);
 	dev_pm_domain_detach(pd_dev, true);
 err_attach:
 	while (--i >= 0) {
+		dev_pm_opp_clear_config(pds->opp_tokens[i]);
 		if (pds->pd_links[i])
 			device_link_del(pds->pd_links[i]);
 		dev_pm_domain_detach(pds->pd_devs[i], true);
@@ -361,6 +379,7 @@ void dev_pm_domain_detach_list(struct dev_pm_domain_list *list)
 		return;
 
 	for (i = 0; i < list->num_pds; i++) {
+		dev_pm_opp_clear_config(list->opp_tokens[i]);
 		if (list->pd_links[i])
 			device_link_del(list->pd_links[i]);
 		dev_pm_domain_detach(list->pd_devs[i], true);

include/linux/pm_domain.h

@@ -30,9 +30,16 @@
  *				supplier and its PM domain when creating the
  *				device-links.
  *
+ * PD_FLAG_REQUIRED_OPP:	Assign required_devs for the required OPPs. The
+ *				index of the required OPP must correspond to the
+ *				index in the array of the pd_names. If pd_names
+ *				isn't specified, the index just follows the
+ *				index for the attached PM domain.
+ *
  */
 #define PD_FLAG_NO_DEV_LINK		BIT(0)
 #define PD_FLAG_DEV_LINK_ON		BIT(1)
+#define PD_FLAG_REQUIRED_OPP		BIT(2)
 
 struct dev_pm_domain_attach_data {
 	const char * const *pd_names;
@@ -43,6 +50,7 @@ struct dev_pm_domain_attach_data {
 struct dev_pm_domain_list {
 	struct device **pd_devs;
 	struct device_link **pd_links;
+	u32 *opp_tokens;
 	u32 num_pds;
 };