diff options
| -rw-r--r-- | drivers/net/phy/dp83tg720.c | 78 | ||||
| -rw-r--r-- | drivers/net/phy/phy.c | 21 | ||||
| -rw-r--r-- | include/linux/phy.h | 13 |
3 files changed, 111 insertions, 1 deletions
diff --git a/drivers/net/phy/dp83tg720.c b/drivers/net/phy/dp83tg720.c index 050f4537d140..7e76323409c4 100644 --- a/drivers/net/phy/dp83tg720.c +++ b/drivers/net/phy/dp83tg720.c @@ -4,12 +4,31 @@ */ #include <linux/bitfield.h> #include <linux/ethtool_netlink.h> +#include <linux/jiffies.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/phy.h> +#include <linux/random.h> #include "open_alliance_helpers.h" +/* + * DP83TG720S_POLL_ACTIVE_LINK - Polling interval in milliseconds when the link + * is active. + * DP83TG720S_POLL_NO_LINK_MIN - Minimum polling interval in milliseconds when + * the link is down. + * DP83TG720S_POLL_NO_LINK_MAX - Maximum polling interval in milliseconds when + * the link is down. + * + * These values are not documented or officially recommended by the vendor but + * were determined through empirical testing. They achieve a good balance in + * minimizing the number of reset retries while ensuring reliable link recovery + * within a reasonable timeframe. + */ +#define DP83TG720S_POLL_ACTIVE_LINK 1000 +#define DP83TG720S_POLL_NO_LINK_MIN 100 +#define DP83TG720S_POLL_NO_LINK_MAX 1000 + #define DP83TG720S_PHY_ID 0x2000a284 /* MDIO_MMD_VEND2 registers */ @@ -371,6 +390,13 @@ static int dp83tg720_read_status(struct phy_device *phydev) if (ret) return ret; + /* Sleep 600ms for PHY stabilization post-reset. + * Empirically chosen value (not documented). + * Helps reduce reset bounces with link partners having similar + * issues. + */ + msleep(600); + /* After HW reset we need to restore master/slave configuration. * genphy_c45_pma_baset1_read_master_slave() call will be done * by the dp83tg720_config_aneg() function. @@ -498,6 +524,57 @@ static int dp83tg720_probe(struct phy_device *phydev) return 0; } +/** + * dp83tg720_get_next_update_time - Determine the next update time for PHY + * state + * @phydev: Pointer to the phy_device structure + * + * This function addresses a limitation of the DP83TG720 PHY, which cannot + * reliably detect or report a stable link state. To recover from such + * scenarios, the PHY must be periodically reset when the link is down. However, + * if the link partner also runs Linux with the same driver, synchronized reset + * intervals can lead to a deadlock where the link never establishes due to + * simultaneous resets on both sides. + * + * To avoid this, the function implements randomized polling intervals when the + * link is down. It ensures that reset intervals are desynchronized by + * introducing a random delay between a configured minimum and maximum range. + * When the link is up, a fixed polling interval is used to minimize overhead. + * + * This mechanism guarantees that the link will reestablish within 10 seconds + * in the worst-case scenario. + * + * Return: Time (in jiffies) until the next update event for the PHY state + * machine. + */ +static unsigned int dp83tg720_get_next_update_time(struct phy_device *phydev) +{ + unsigned int next_time_jiffies; + + if (phydev->link) { + /* When the link is up, use a fixed 1000ms interval + * (in jiffies) + */ + next_time_jiffies = + msecs_to_jiffies(DP83TG720S_POLL_ACTIVE_LINK); + } else { + unsigned int min_jiffies, max_jiffies, rand_jiffies; + + /* When the link is down, randomize interval between min/max + * (in jiffies) + */ + min_jiffies = msecs_to_jiffies(DP83TG720S_POLL_NO_LINK_MIN); + max_jiffies = msecs_to_jiffies(DP83TG720S_POLL_NO_LINK_MAX); + + rand_jiffies = min_jiffies + + get_random_u32_below(max_jiffies - min_jiffies + 1); + next_time_jiffies = rand_jiffies; + } + + /* Ensure the polling time is at least one jiffy */ + return max(next_time_jiffies, 1U); +} + static struct phy_driver dp83tg720_driver[] = { { PHY_ID_MATCH_MODEL(DP83TG720S_PHY_ID), @@ -516,6 +593,7 @@ static struct phy_driver dp83tg720_driver[] = { .get_link_stats = dp83tg720_get_link_stats, .get_phy_stats = dp83tg720_get_phy_stats, .update_stats = dp83tg720_update_stats, + .get_next_update_time = dp83tg720_get_next_update_time, .suspend = genphy_suspend, .resume = genphy_resume, diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c index d0c1718e2b16..347ad1b64497 100644 --- a/drivers/net/phy/phy.c +++ b/drivers/net/phy/phy.c @@ -1501,6 +1501,24 @@ void phy_free_interrupt(struct phy_device *phydev) } EXPORT_SYMBOL(phy_free_interrupt); +/** + * phy_get_next_update_time - Determine the next PHY update time + * @phydev: Pointer to the phy_device structure + * + * This function queries the PHY driver to get the time for the next polling + * event. If the driver does not implement the callback, a default value is + * used. + * + * Return: The time for the next polling event in jiffies + */ +static unsigned int phy_get_next_update_time(struct phy_device *phydev) +{ + if (phydev->drv && phydev->drv->get_next_update_time) + return phydev->drv->get_next_update_time(phydev); + + return PHY_STATE_TIME; +} + enum phy_state_work { PHY_STATE_WORK_NONE, PHY_STATE_WORK_ANEG, @@ -1580,7 +1598,8 @@ static enum phy_state_work _phy_state_machine(struct phy_device *phydev) * called from phy_disconnect() synchronously. */ if (phy_polling_mode(phydev) && phy_is_started(phydev)) - phy_queue_state_machine(phydev, PHY_STATE_TIME); + phy_queue_state_machine(phydev, + phy_get_next_update_time(phydev)); return state_work; } diff --git a/include/linux/phy.h b/include/linux/phy.h index 83994b394d8e..64982eba71d1 100644 --- a/include/linux/phy.h +++ b/include/linux/phy.h @@ -1270,6 +1270,19 @@ struct phy_driver { */ int (*led_polarity_set)(struct phy_device *dev, int index, unsigned long modes); + + /** + * @get_next_update_time: Get the time until the next update event + * @dev: PHY device + * + * Callback to determine the time (in jiffies) until the next + * update event for the PHY state machine. Allows PHY drivers to + * dynamically adjust polling intervals based on link state or other + * conditions. + * + * Returns the time in jiffies until the next update event. + */ + unsigned int (*get_next_update_time)(struct phy_device *dev); }; #define to_phy_driver(d) container_of_const(to_mdio_common_driver(d), \ struct phy_driver, mdiodrv) |