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

Kory Maincent
2024-06-25T12:34:03Z

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;
+ }
+ 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