Re: [PATCH net-next v7 04/13] net: pse-pd: Add support for PSE power domains

[Oleksij Rempel <o.rempel@pengutronix.de>]

Hi Kory,

here are some points

On Tue, Apr 08, 2025 at 04:32:13PM +0200, Kory Maincent wrote:
> From: Kory Maincent (Dent Project) <kory.maincent@bootlin.com>
> 
> Introduce PSE power domain support as groundwork for upcoming port
> priority features. Multiple PSE PIs can now be grouped under a single
> PSE power domain, enabling future enhancements like defining available
> power budgets, port priority modes, and disconnection policies. This
> setup will allow the system to assess whether activating a port would
> exceed the available power budget, preventing over-budget states
> proactively.
> 
> Signed-off-by: Kory Maincent (Dent Project) <kory.maincent@bootlin.com>
> ---
> Changes in v7:
> - Add reference count and mutex lock for PSE power domain in case of PSE
>   from different controllers want to register the same PSE power domain.
> 
> Changes in v6:
> - nitpick change.
> 
> Changes in v4:
> - Add kdoc.
> - Fix null dereference in pse_flush_pw_ds function.
> 
> Changes in v3:
> - Remove pw_budget variable.
> 
> Changes in v2:
> - new patch.
> ---
>  drivers/net/pse-pd/pse_core.c | 138 ++++++++++++++++++++++++++++++++++++++++++
>  include/linux/pse-pd/pse.h    |   2 +
>  2 files changed, 140 insertions(+)
> 
> diff --git a/drivers/net/pse-pd/pse_core.c b/drivers/net/pse-pd/pse_core.c
> index 8755c2e00b6a..d26045e6ca85 100644
> --- a/drivers/net/pse-pd/pse_core.c
> +++ b/drivers/net/pse-pd/pse_core.c
> @@ -13,8 +13,12 @@
>  #include <linux/regulator/driver.h>
>  #include <linux/regulator/machine.h>
>  
> +#define PSE_PW_D_LIMIT INT_MAX
> +
>  static DEFINE_MUTEX(pse_list_mutex);
>  static LIST_HEAD(pse_controller_list);
> +static DEFINE_XARRAY_ALLOC(pse_pw_d_map);
> +static DEFINE_MUTEX(pse_pw_d_mutex);
>  
>  /**
>   * struct pse_control - a PSE control
> @@ -35,6 +39,18 @@ struct pse_control {
>  	struct phy_device *attached_phydev;
>  };
>  
> +/**
> + * struct pse_power_domain - a PSE power domain
> + * @id: ID of the power domain
> + * @supply: Power supply the Power Domain
> + * @refcnt: Number of gets of this pse_power_domain
> + */
> +struct pse_power_domain {
> +	int id;
> +	struct regulator *supply;
> +	struct kref refcnt;
> +};
> +
>  static int of_load_single_pse_pi_pairset(struct device_node *node,
>  					 struct pse_pi *pi,
>  					 int pairset_num)
> @@ -440,6 +456,123 @@ devm_pse_pi_regulator_register(struct pse_controller_dev *pcdev,
>  	return 0;
>  }
>  
> +static void __pse_pw_d_release(struct kref *kref)
> +{
> +	struct pse_power_domain *pw_d = container_of(kref,
> +						     struct pse_power_domain,
> +						     refcnt);
> +
> +	regulator_put(pw_d->supply);
> +	xa_erase(&pse_pw_d_map, pw_d->id);
> +}
> +
> +/**
> + * pse_flush_pw_ds - flush all PSE power domains of a PSE
> + * @pcdev: a pointer to the initialized PSE controller device
> + */
> +static void pse_flush_pw_ds(struct pse_controller_dev *pcdev)
> +{
> +	struct pse_power_domain *pw_d;
> +	int i;
> +
> +	for (i = 0; i < pcdev->nr_lines; i++) {
> +		if (!pcdev->pi[i].pw_d)
> +			continue;
> +
> +		pw_d = xa_load(&pse_pw_d_map, pcdev->pi[i].pw_d->id);
> +		if (!pw_d)
> +			continue;
> +
> +		kref_put_mutex(&pw_d->refcnt, __pse_pw_d_release,
> +			       &pse_pw_d_mutex);
> +	}
> +}
> +
> +/**
> + * devm_pse_alloc_pw_d - allocate a new PSE power domain for a device
> + * @dev: device that is registering this PSE power domain
> + *
> + * Return: Pointer to the newly allocated PSE power domain or error pointers
> + */
> +static struct pse_power_domain *devm_pse_alloc_pw_d(struct device *dev)
> +{
> +	struct pse_power_domain *pw_d;
> +	int index, ret;
> +
> +	pw_d = devm_kzalloc(dev, sizeof(*pw_d), GFP_KERNEL);
> +	if (!pw_d)
> +		return ERR_PTR(-ENOMEM);
> +
> +	ret = xa_alloc(&pse_pw_d_map, &index, pw_d, XA_LIMIT(1, PSE_PW_D_LIMIT),
> +		       GFP_KERNEL);
> +	if (ret)
> +		return ERR_PTR(ret);

Missing "kref_init(&pw_d->refcnt);" ?

> +	pw_d->id = index;
> +	return pw_d;
> +}
> +
> +/**
> + * pse_register_pw_ds - register the PSE power domains for a PSE
> + * @pcdev: a pointer to the PSE controller device
> + *
> + * Return: 0 on success and failure value on error
> + */
> +static int pse_register_pw_ds(struct pse_controller_dev *pcdev)
> +{
> +	int i, ret = 0;
> +
> +	mutex_lock(&pse_pw_d_mutex);
> +	for (i = 0; i < pcdev->nr_lines; i++) {
> +		struct regulator_dev *rdev = pcdev->pi[i].rdev;
> +		struct pse_power_domain *pw_d;
> +		struct regulator *supply;
> +		bool present = false;
> +		unsigned long index;
> +
> +		/* No regulator or regulator parent supply registered.
> +		 * We need a regulator parent to register a PSE power domain
> +		 */
> +		if (!rdev || !rdev->supply)
> +			continue;
> +
> +		xa_for_each(&pse_pw_d_map, index, pw_d) {
> +			/* Power supply already registered as a PSE power
> +			 * domain.
> +			 */
> +			if (regulator_is_equal(pw_d->supply, rdev->supply)) {
> +				present = true;
> +				pcdev->pi[i].pw_d = pw_d;
> +				break;
> +			}
> +		}
> +		if (present) {
> +			kref_get(&pw_d->refcnt);
> +			continue;
> +		}
> +
> +		pw_d = devm_pse_alloc_pw_d(pcdev->dev);
> +		if (IS_ERR_OR_NULL(pw_d)) {

s/IS_ERR_OR_NULL/IS_ERR

devm_pse_alloc_pw_d() is not returning NULL.

> +			ret = PTR_ERR(pw_d);
> +			goto out;
> +		}
> +
> +		supply = regulator_get(&rdev->dev, rdev->supply_name);
> +		if (IS_ERR(supply)) {
> +			xa_erase(&pse_pw_d_map, pw_d->id);
> +			ret = PTR_ERR(supply);

Here:
Either we need to ensure pse_flush_pw_ds() handles incomplete setups
or immediately clean up earlier entries in the loop when an error
occurs.

> +			goto out;
> +		}
> +
> +		pw_d->supply = supply;
> +		pcdev->pi[i].pw_d = pw_d;
> +	}
> +
> +out:
> +	mutex_unlock(&pse_pw_d_mutex);
> +	return ret;
> +}
 

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