RE: [PATCH net-next v4 4/7] net: pse-pd: Add new power limit get and set c33 features

Sai Krishna Gajula
2024-06-25T18:49:48Z

> -----Original Message-----
> From: Kory Maincent <kory.maincent@bootlin.com>
> Sent: Tuesday, June 25, 2024 6:04 PM
> To: David S. Miller <davem@davemloft.net>; Eric Dumazet
> <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo Abeni
> <pabeni@redhat.com>; Donald Hunter <donald.hunter@gmail.com>; Oleksij
> Rempel <o.rempel@pengutronix.de>; Jonathan Corbet <corbet@lwn.net>
> Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>; linux-
> kernel@vger.kernel.org; netdev@vger.kernel.org; Dent Project
> <dentproject@linuxfoundation.org>; kernel@pengutronix.de; linux-
> doc@vger.kernel.org; Kory Maincent <kory.maincent@bootlin.com>
> Subject: [PATCH net-next v4 4/7] net: pse-pd: Add new power
> limit get and set c33 features
>
> From: Kory Maincent (Dent Project) <kory. maincent@ bootlin. com> This
> patch add a way to get and set the power limit of a PSE PI. For that it uses
> regulator API callbacks wrapper like get_voltage() and get/set_current_limit()
> as power
> From: Kory Maincent (Dent Project) <kory.maincent@bootlin.com>
>
> This patch add a way to get and set the power limit of a PSE PI.
> For that it uses regulator API callbacks wrapper like get_voltage() and
> get/set_current_limit() as power is simply V * I.
> We used mW unit as defined by the IEEE 802.3-2022 standards.
>
> set_current_limit() uses the voltage return by get_voltage() and the desired
> power limit to calculate the current limit. get_voltage() callback is then
> mandatory to set the power limit.
>
> get_current_limit() callback is by default looking at a driver callback and
> fallback to extracting the current limit from _pse_ethtool_get_status() if the
> driver does not set its callback. We prefer let the user the choice because
> ethtool_get_status return much more information than the current limit.
>
> expand pse status with c33_pw_limit_ranges to return the ranges available to
> configure the power limit.
>
> Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
> ---
>
> Change in v2:
> - Use uA and uV instead of mA and mV to have more precision in the power
> calculation. Need to use 64bit variables for the calculation.
>
> Change in v4:
> - Rename the power limit value to c33_avail_pw_limit.
> - Add support for c33_pw_limit_ranges
> ---
> drivers/net/pse-pd/pse_core.c | 172
> +++++++++++++++++++++++++++++++++++++++---
> include/linux/pse-pd/pse.h | 43 +++++++++++
> 2 files changed, 204 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/net/pse-pd/pse_core.c b/drivers/net/pse-pd/pse_core.c
> index 795ab264eaf2..c592ed0469f5 100644
> --- a/drivers/net/pse-pd/pse_core.c
> +++ b/drivers/net/pse-pd/pse_core.c
> @@ -265,10 +265,113 @@ static int pse_pi_disable(struct regulator_dev
> *rdev)
> return ret;
> }
>
> +static int _pse_pi_get_voltage(struct regulator_dev *rdev) {
> + struct pse_controller_dev *pcdev = rdev_get_drvdata(rdev);
> + const struct pse_controller_ops *ops;
> + int id;
> +
> + ops = pcdev->ops;
> + if (!ops->pi_get_voltage)
> + return -EOPNOTSUPP;
> +
> + id = rdev_get_id(rdev);
> + return ops->pi_get_voltage(pcdev, id); }
> +
> +static int pse_pi_get_voltage(struct regulator_dev *rdev) {
> + struct pse_controller_dev *pcdev = rdev_get_drvdata(rdev);
> + int ret;
> +
> + mutex_lock(&pcdev->lock);
> + ret = _pse_pi_get_voltage(rdev);
> + mutex_unlock(&pcdev->lock);
> +
> + return ret;
> +}
> +
> +static int _pse_ethtool_get_status(struct pse_controller_dev *pcdev,
> + int id,
> + struct netlink_ext_ack *extack,
> + struct pse_control_status *status);
> +
> +static int pse_pi_get_current_limit(struct regulator_dev *rdev) {
> + struct pse_controller_dev *pcdev = rdev_get_drvdata(rdev);
> + const struct pse_controller_ops *ops;
> + struct netlink_ext_ack extack = {};
> + struct pse_control_status st = {};
> + int id, uV, ret;
> + s64 tmp_64;
> +
> + ops = pcdev->ops;
> + id = rdev_get_id(rdev);
> + mutex_lock(&pcdev->lock);
> + if (ops->pi_get_current_limit) {
> + ret = ops->pi_get_current_limit(pcdev, id);
> + goto out;
> + }
> +
> + /* If pi_get_current_limit() callback not populated get voltage
> + * from pi_get_voltage() and power limit from ethtool_get_status()
> + * to calculate current limit.
> + */
> + ret = _pse_pi_get_voltage(rdev);
> + if (!ret) {
> + dev_err(pcdev->dev, "Voltage null\n");
> + ret = -ERANGE;
> + goto out;
> + }
> + if (ret < 0)
> + goto out;
> + uV = ret;
> +
> + ret = _pse_ethtool_get_status(pcdev, id, &extack, &st);
> + if (ret)
> + goto out;
> +
> + if (!st.c33_avail_pw_limit) {
> + ret = -ENODATA;
> + goto out;
> + }
> +
> + tmp_64 = st.c33_avail_pw_limit;
> + tmp_64 *= 1000000000ull;
> + /* uA = mW * 1000000000 / uV */
> + ret = DIV_ROUND_CLOSEST_ULL(tmp_64, uV);
> +
> +out:
> + mutex_unlock(&pcdev->lock);
> + return ret;
> +}
> +
> +static int pse_pi_set_current_limit(struct regulator_dev *rdev, int min_uA,
> + int max_uA)
> +{
> + struct pse_controller_dev *pcdev = rdev_get_drvdata(rdev);
> + const struct pse_controller_ops *ops;
> + int id, ret;
> +
> + ops = pcdev->ops;
> + if (!ops->pi_set_current_limit)
> + return -EOPNOTSUPP;
> +
> + id = rdev_get_id(rdev);
> + mutex_lock(&pcdev->lock);
> + ret = ops->pi_set_current_limit(pcdev, id, max_uA);
> + mutex_unlock(&pcdev->lock);
> +
> + return ret;
> +}
> +
> static const struct regulator_ops pse_pi_ops = {
> .is_enabled = pse_pi_is_enabled,
> .enable = pse_pi_enable,
> .disable = pse_pi_disable,
> + .get_voltage = pse_pi_get_voltage,
> + .get_current_limit = pse_pi_get_current_limit,
> + .set_current_limit = pse_pi_set_current_limit,
> };
>
> static int
> @@ -298,7 +401,9 @@ devm_pse_pi_regulator_register(struct
> pse_controller_dev *pcdev,
> rdesc->ops = &pse_pi_ops;
> rdesc->owner = pcdev->owner;
>
> - rinit_data->constraints.valid_ops_mask =
> REGULATOR_CHANGE_STATUS;
> + rinit_data->constraints.valid_ops_mask =
> REGULATOR_CHANGE_STATUS |
> +
> REGULATOR_CHANGE_CURRENT;
> + rinit_data->constraints.max_uA = MAX_PI_CURRENT;
> rinit_data->supply_regulator = "vpwr";
>
> rconfig.dev = pcdev->dev;
> @@ -626,6 +731,23 @@ struct pse_control *of_pse_control_get(struct
> device_node *node) } EXPORT_SYMBOL_GPL(of_pse_control_get);
>
> +static int _pse_ethtool_get_status(struct pse_controller_dev *pcdev,
> + int id,
> + struct netlink_ext_ack *extack,
> + struct pse_control_status *status) {
> + const struct pse_controller_ops *ops;
> +
> + ops = pcdev->ops;
> + if (!ops->ethtool_get_status) {
> + NL_SET_ERR_MSG(extack,
> + "PSE driver does not support status report");
> + return -EOPNOTSUPP;
> + }
> +
> + return ops->ethtool_get_status(pcdev, id, extack, status); }
> +
> /**
> * pse_ethtool_get_status - get status of PSE control
> * @psec: PSE control pointer
> @@ -638,19 +760,10 @@ int pse_ethtool_get_status(struct pse_control *psec,
> struct netlink_ext_ack *extack,
> struct pse_control_status *status) {
> - const struct pse_controller_ops *ops;
> int err;
>
> - ops = psec->pcdev->ops;
> -
> - if (!ops->ethtool_get_status) {
> - NL_SET_ERR_MSG(extack,
> - "PSE driver does not support status report");
> - return -EOPNOTSUPP;
> - }
> -
> mutex_lock(&psec->pcdev->lock);
> - err = ops->ethtool_get_status(psec->pcdev, psec->id, extack, status);
> + err = _pse_ethtool_get_status(psec->pcdev, psec->id, extack, status);
> mutex_unlock(&psec->pcdev->lock);
>
> return err;
> @@ -732,6 +845,43 @@ int pse_ethtool_set_config(struct pse_control *psec,
> } EXPORT_SYMBOL_GPL(pse_ethtool_set_config);
>
> +/**
> + * pse_ethtool_set_pw_limit - set PSE control power limit
> + * @psec: PSE control pointer
> + * @extack: extack for reporting useful error messages
> + * @pw_limit: power limit value in mW
> + *
> + * Return: 0 on success and failure value on error */ int
> +pse_ethtool_set_pw_limit(struct pse_control *psec,
> + struct netlink_ext_ack *extack,
> + const unsigned int pw_limit)
> +{
> + int uV, uA, ret;
> + s64 tmp_64;
> +
> + ret = regulator_get_voltage(psec->ps);
> + if (!ret) {
> + NL_SET_ERR_MSG(extack,
> + "Can't read current voltage");
> + return ret;
> + }
> + if (ret < 0) {
> + NL_SET_ERR_MSG(extack,
> + "Error reading current voltage");
> + return ret;
> + }

Is there any significance of checking "ret" value against '0' and '< 0' separately? Just trying to understand, these checks reflect regulator failure etc..?

> + uV = ret;
> +
> + tmp_64 = pw_limit;
> + tmp_64 *= 1000000000ull;
> + /* uA = mW * 1000000000 / uV */
> + uA = DIV_ROUND_CLOSEST_ULL(tmp_64, uV);
> +
> + return regulator_set_current_limit(psec->ps, 0, uA); }
> +EXPORT_SYMBOL_GPL(pse_ethtool_set_pw_limit);
> +
> bool pse_has_podl(struct pse_control *psec) {
> return psec->pcdev->types & ETHTOOL_PSE_PODL; diff --git
> a/include/linux/pse-pd/pse.h b/include/linux/pse-pd/pse.h index
> 38b9308e5e7a..591a53e082e6 100644
> --- a/include/linux/pse-pd/pse.h
> +++ b/include/linux/pse-pd/pse.h
> @@ -9,6 +9,9 @@
> #include <linux/list.h>
> #include <uapi/linux/ethtool.h>
>
> +/* Maximum current in uA according to IEEE 802.3-2022 Table 145-1 */
> +#define MAX_PI_CURRENT 1920000
> +
> struct phy_device;
> struct pse_controller_dev;
>
> @@ -41,6 +44,12 @@ struct pse_control_config {
> * @c33_actual_pw: power currently delivered by the PSE in mW
> * IEEE 802.3-2022 30.9.1.1.23 aPSEActualPower
> * @c33_ext_state_info: extended state information of the PSE
> + * @c33_avail_pw_limit: available power limit of the PSE in mW
> + * IEEE 802.3-2022 145.2.5.4 pse_avail_pwr
> + * @c33_pw_limit_ranges: supported power limit configuration range. The
> driver
> + * is in charge of the memory allocation.
> + * @c33_pw_limit_nb_ranges: number of supported power limit
> configuration
> + * ranges
> */
> struct pse_control_status {
> enum ethtool_podl_pse_admin_state podl_admin_state; @@ -50,6
> +59,9 @@ struct pse_control_status {
> u32 c33_pw_class;
> u32 c33_actual_pw;
> struct ethtool_c33_pse_ext_state_info c33_ext_state_info;
> + u32 c33_avail_pw_limit;
> + struct ethtool_c33_pse_pw_limit_range *c33_pw_limit_ranges;
> + u32 c33_pw_limit_nb_ranges;
> };
>
> /**
> @@ -61,6 +73,14 @@ struct pse_control_status {
> * May also return negative errno.
> * @pi_enable: Configure the PSE PI as enabled.
> * @pi_disable: Configure the PSE PI as disabled.
> + * @pi_get_voltage: Return voltage similarly to get_voltage regulator
> + * callback.
> + * @pi_get_current_limit: Get the configured current limit similarly to
> + * get_current_limit regulator callback.
> + * @pi_set_current_limit: Configure the current limit similarly to
> + * set_current_limit regulator callback.
> + * Should not return an error in case of
> MAX_PI_CURRENT
> + * current value set.
> */
> struct pse_controller_ops {
> int (*ethtool_get_status)(struct pse_controller_dev *pcdev, @@ -70,6
> +90,11 @@ struct pse_controller_ops {
> int (*pi_is_enabled)(struct pse_controller_dev *pcdev, int id);
> int (*pi_enable)(struct pse_controller_dev *pcdev, int id);
> int (*pi_disable)(struct pse_controller_dev *pcdev, int id);
> + int (*pi_get_voltage)(struct pse_controller_dev *pcdev, int id);
> + int (*pi_get_current_limit)(struct pse_controller_dev *pcdev,
> + int id);
> + int (*pi_set_current_limit)(struct pse_controller_dev *pcdev,
> + int id, int max_uA);
> };
>
> struct module;
> @@ -156,6 +181,11 @@ int pse_ethtool_get_status(struct pse_control *psec,
> int pse_ethtool_set_config(struct pse_control *psec,
> struct netlink_ext_ack *extack,
> const struct pse_control_config *config);
> +int pse_ethtool_set_pw_limit(struct pse_control *psec,
> + struct netlink_ext_ack *extack,
> + const unsigned int pw_limit);
> +int pse_ethtool_get_pw_limit(struct pse_control *psec,
> + struct netlink_ext_ack *extack);
>
> bool pse_has_podl(struct pse_control *psec); bool pse_has_c33(struct
> pse_control *psec); @@ -185,6 +215,19 @@ static inline int
> pse_ethtool_set_config(struct pse_control *psec,
> return -EOPNOTSUPP;
> }
>
> +static inline int pse_ethtool_set_pw_limit(struct pse_control *psec,
> + struct netlink_ext_ack *extack,
> + const unsigned int pw_limit)
> +{
> + return -EOPNOTSUPP;
> +}
> +
> +static inline int pse_ethtool_get_pw_limit(struct pse_control *psec,
> + struct netlink_ext_ack *extack) {
> + return -EOPNOTSUPP;
> +}
> +
> static inline bool pse_has_podl(struct pse_control *psec) {
> return false;
>
> --
> 2.34.1
>
Reviewed-by: Sai Krishna <saikrishnag@marvell.com>