On Fri, 2026-01-23 at 14:44 +0000, Matt Coster wrote:
> 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.
> 
> Signed-off-by: Matt Coster <[email protected]>

Reviewed-by: Alessio Belle <[email protected]>

Thanks,
Alessio

> ---
> We've had this patch kicking around internally for a while; it's been
> held up by discussions as to whether we actually need the dependencies
> between domains for the hardware to behave currectly. As it turns out,
> the answer is yes.
> 
> Geert sent a similar patch[1] yesterday which didn't retain the
> inter-domain links and suggested we just send this one instead of
> reworking his. Thank you for the kick up the backside to progress this
> one! :)
> 
> [1]: 
> https://lore.kernel.org/r/194465eda54d1f852a9226cf691ddc5aa208e0a3.1769097977.git.geert+rene...@glider.be/
> ---
>  drivers/gpu/drm/imagination/pvr_device.h | 10 ++--
>  drivers/gpu/drm/imagination/pvr_power.c  | 80 
> ++++++++++++--------------------
>  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 cfda215e7428e..d51c57cf93323 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 b9f801c63260c..a0834c550a852 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 @@ int pvr_power_domains_init(struct pvr_device *pvr_dev)
>       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 };
>  }
> 
> ---
> base-commit: 15bd2f5d52de890f745ac0c60a44cd27d095bb0d
> change-id: 20251201-pm-domain-attach-list-ef4ec12a9271
> 

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