Now that the PHY reset logic includes a role-specific asymmetric delay
to avoid synchronized reset deadlocks, the previously used randomized
polling intervals are no longer necessary.
This patch removes the get_random_u32_below()-based logic and introduces
an adaptive polling strategy:
- Fast polling for a short time after link-down
- Slow polling if the link remains down
- Slower polling when the link is up
This balances CPU usage and responsiveness while avoiding reset
collisions. Additionally, the driver still relies on polling for
all link state changes, as interrupt support is not implemented,
and link-up events are not reliably signaled by the PHY.
The polling parameters are now documented in the updated top-of-file
comment.
Co-developed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: David Jander <david@protonic.nl>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250612104157.2262058-4-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Now that dp83tg720_soft_reset() introduces role-specific delays to avoid
reset synchronization deadlocks, the fixed 600ms post-reset delay in
dp83tg720_read_status() is no longer needed.
The new logic provides both the required MDC timing and link stabilization,
making the old empirical delay redundant and unnecessarily long.
Co-developed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: David Jander <david@protonic.nl>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250612104157.2262058-3-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add a .soft_reset callback for the DP83TG720 PHY that issues a hardware
reset followed by an asymmetric post-reset delay. The delay differs
based on the PHY's master/slave role to avoid synchronized reset
deadlocks, which are known to occur when both link partners use
identical reset intervals.
The delay includes:
- a fixed 1ms wait to satisfy MDC access timing per datasheet, and
- an empirically chosen extra delay (97ms for master, 149ms for slave).
Co-developed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: David Jander <david@protonic.nl>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250612104157.2262058-2-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Address the limitations of the DP83TG720 PHY, which cannot reliably
detect or report a stable link state. To handle this, the PHY must be
periodically reset when the link is down. However, synchronized reset
intervals between the PHY and its link partner can result in a deadlock,
preventing the link from re-establishing.
This change introduces a randomized polling interval when the link is
down to desynchronize resets between link partners.
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250210082358.200751-3-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
'struct mdio_device_id' is not modified in these drivers.
Constifying these structures moves some data to a read-only section, so
increase overall security.
On a x86_64, with allmodconfig, as an example:
Before:
======
text data bss dec hex filename
27014 12792 0 39806 9b7e drivers/net/phy/broadcom.o
After:
=====
text data bss dec hex filename
27206 12600 0 39806 9b7e drivers/net/phy/broadcom.o
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/403c381b7d9156b67ad68ffc44b8eee70c5e86a9.1736691226.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add support for reporting PHY statistics in the DP83TG720 driver. This
includes cumulative tracking of link loss events, transmit/receive
packet counts, and error counts. Implemented functions to update and
provide statistics via ethtool, with optional polling support enabled
through `PHY_POLL_STATS`.
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Introduce cable testing support for the DP83TG720 PHY. This implementation
is based on the "DP83TG720S-Q1: Configuring for Open Alliance Specification
Compliance (Rev. B)" application note.
The feature has been tested with cables of various lengths:
- No cable: 1m till open reported.
- 5 meter cable: reported properly.
- 20 meter cable: reported as 19m.
- 40 meter cable: reported as cable ok.
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://patch.msgid.link/20240812073046.1728288-3-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Get master/slave configuration for initial system start with the link in
down state. This ensures ethtool shows current configuration. Also
fixes link reconfiguration with ethtool while in down state, preventing
ethtool from displaying outdated configuration.
Even though dp83tg720_config_init() is executed periodically as long as
the link is in admin up state but no carrier is detected, this is not
sufficient for the link in admin down state where
dp83tg720_read_status() is not periodically executed. To cover this
case, we need an extra read role configuration in
dp83tg720_config_aneg().
Fixes: cb80ee2f9b ("net: phy: Add support for the DP83TG720S Ethernet PHY")
Cc: stable@vger.kernel.org
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20240614094516.1481231-2-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The DP83TG720S-Q1 device is an IEEE 802.3bp and Open Alliance compliant
automotive Ethernet physical layer transceiver.
This driver was tested with i.MX8MP EQOS (stmmac) on the MAC side and
same TI PHY on other side.
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/20231212054144.87527-3-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
