drm/imagination: Use dev_pm_domain_attach_list()

This helper handles the attaching and linking of the entire list of power
domains. Besides making pvr_power_domains_init() simpler, this also lays
the groundwork to simplify supporting the varied power domain names used in
Volcanic GPU cores.

Note that we still need to create the links between power domains to ensure
they're brought up in a valid sequence.

Reviewed-by: Alessio Belle <alessio.belle@imgtec.com>
Link: https://patch.msgid.link/20260123-pm-domain-attach-list-v1-1-d51dd7e43253@imgtec.com
Signed-off-by: Matt Coster <matt.coster@imgtec.com>

2 files changed, 33 insertions, 57 deletions

diff --git a/drivers/gpu/drm/imagination/pvr_device.h b/drivers/gpu/drm/imagination/pvr_device.h
index cfda215e7428..d51c57cf9332 100644
--- a/drivers/gpu/drm/imagination/pvr_device.h
+++ b/drivers/gpu/drm/imagination/pvr_device.h
@@ -152,15 +152,13 @@ struct pvr_device {
 	 * @power: Optional power domain devices.
 	 *
 	 * On platforms with more than one power domain for the GPU, they are
-	 * stored here in @domain_devs, along with links between them in
-	 * @domain_links. The size of @domain_devs is given by @domain_count,
-	 * while the size of @domain_links is (2 * @domain_count) - 1.
+	 * stored here in @domains, along with links between them in
+	 * @domain_links. The size of @domain_links is one less than
+	 * struct dev_pm_domain_list->num_pds in @domains.
 	 */
 	struct pvr_device_power {
-		struct device **domain_devs;
+		struct dev_pm_domain_list *domains;
 		struct device_link **domain_links;
-
-		u32 domain_count;
 	} power;
 
 	/**
diff --git a/drivers/gpu/drm/imagination/pvr_power.c b/drivers/gpu/drm/imagination/pvr_power.c
index b9f801c63260..a0834c550a85 100644
--- a/drivers/gpu/drm/imagination/pvr_power.c
+++ b/drivers/gpu/drm/imagination/pvr_power.c
@@ -593,14 +593,16 @@ pvr_watchdog_fini(struct pvr_device *pvr_dev)
 
 int pvr_power_domains_init(struct pvr_device *pvr_dev)
 {
-	struct device *dev = from_pvr_device(pvr_dev)->dev;
+	static const char *const ROGUE_PD_NAMES[] = { "a", "b", "c", "d", "e" };
+
+	struct drm_device *drm_dev = from_pvr_device(pvr_dev);
+	struct device *dev = drm_dev->dev;
 
 	struct device_link **domain_links __free(kfree) = NULL;
-	struct device **domain_devs __free(kfree) = NULL;
+	struct dev_pm_domain_list *domains = NULL;
 	int domain_count;
 	int link_count;
 
-	char dev_name[2] = "a";
 	int err;
 	int i;
 
@@ -612,46 +614,33 @@ int pvr_power_domains_init(struct pvr_device *pvr_dev)
 	if (domain_count <= 1)
 		return 0;
 
-	link_count = domain_count + (domain_count - 1);
+	if (domain_count > ARRAY_SIZE(ROGUE_PD_NAMES)) {
+		drm_err(drm_dev, "%s() only supports %zu domains on Rogue",
+			__func__, ARRAY_SIZE(ROGUE_PD_NAMES));
+		return -EOPNOTSUPP;
+	}
 
-	domain_devs = kcalloc(domain_count, sizeof(*domain_devs), GFP_KERNEL);
-	if (!domain_devs)
-		return -ENOMEM;
+	link_count = domain_count - 1;
 
 	domain_links = kcalloc(link_count, sizeof(*domain_links), GFP_KERNEL);
 	if (!domain_links)
 		return -ENOMEM;
 
-	for (i = 0; i < domain_count; i++) {
-		struct device *domain_dev;
-
-		dev_name[0] = 'a' + i;
-		domain_dev = dev_pm_domain_attach_by_name(dev, dev_name);
-		if (IS_ERR_OR_NULL(domain_dev)) {
-			err = domain_dev ? PTR_ERR(domain_dev) : -ENODEV;
-			goto err_detach;
-		}
-
-		domain_devs[i] = domain_dev;
-	}
-
-	for (i = 0; i < domain_count; i++) {
-		struct device_link *link;
-
-		link = device_link_add(dev, domain_devs[i], DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME);
-		if (!link) {
-			err = -ENODEV;
-			goto err_unlink;
-		}
+	const struct dev_pm_domain_attach_data pd_attach_data = {
+		.pd_names = ROGUE_PD_NAMES,
+		.num_pd_names = domain_count,
+		.pd_flags = 0,
+	};
 
-		domain_links[i] = link;
-	}
+	err = dev_pm_domain_attach_list(dev, &pd_attach_data, &domains);
+	if (err < 0)
+		return err;
 
-	for (i = domain_count; i < link_count; i++) {
+	for (i = 0; i < link_count; i++) {
 		struct device_link *link;
 
-		link = device_link_add(domain_devs[i - domain_count + 1],
-				       domain_devs[i - domain_count],
+		link = device_link_add(domains->pd_devs[i + 1],
+				       domains->pd_devs[i],
 				       DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME);
 		if (!link) {
 			err = -ENODEV;
@@ -662,9 +651,8 @@ int pvr_power_domains_init(struct pvr_device *pvr_dev)
 	}
 
 	pvr_dev->power = (struct pvr_device_power){
-		.domain_devs = no_free_ptr(domain_devs),
+		.domains = domains,
 		.domain_links = no_free_ptr(domain_links),
-		.domain_count = domain_count,
 	};
 
 	return 0;
@@ -673,31 +661,21 @@ err_unlink:
 	while (--i >= 0)
 		device_link_del(domain_links[i]);
 
-	i = domain_count;
-
-err_detach:
-	while (--i >= 0)
-		dev_pm_domain_detach(domain_devs[i], true);
-
 	return err;
 }
 
 void pvr_power_domains_fini(struct pvr_device *pvr_dev)
 {
-	const int domain_count = pvr_dev->power.domain_count;
+	struct pvr_device_power *pvr_power = &pvr_dev->power;
 
-	int i = domain_count + (domain_count - 1);
+	int i = (int)pvr_power->domains->num_pds - 1;
 
 	while (--i >= 0)
-		device_link_del(pvr_dev->power.domain_links[i]);
-
-	i = domain_count;
+		device_link_del(pvr_power->domain_links[i]);
 
-	while (--i >= 0)
-		dev_pm_domain_detach(pvr_dev->power.domain_devs[i], true);
+	dev_pm_domain_detach_list(pvr_power->domains);
 
-	kfree(pvr_dev->power.domain_links);
-	kfree(pvr_dev->power.domain_devs);
+	kfree(pvr_power->domain_links);
 
-	pvr_dev->power = (struct pvr_device_power){ 0 };
+	*pvr_power = (struct pvr_device_power){ 0 };
 }