Add mdio compat string for ASP 2.0 ethernet driver.

Signed-off-by: Justin Chen <justin.chen@broadcom.com>
Acked-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Up until now we have managed not to have the mdio-bcm-unimac manage its
clock except during probe and suspend/resume. This works most of the
time, except where it does not.

With a fully modular build, we can get into a situation whereby the
GENET driver is fully registered, and so is the mdio-bcm-unimac driver,
however the Ethernet PHY driver is not yet, because it depends on a
resource that is not yet available (e.g.: GPIO provider). In that state,
the network device is not usable yet, and so to conserve power, the
GENET driver will have turned off its "main" clock which feeds its MDIO
controller.

When the PHY driver finally probes however, we make an access to the PHY
registers to e.g.: disable interrupts, and this causes a bus error
within the MDIO controller space because the MDIO controller clock(s)
are turned off.

To remedy that, we manage the clock around all of the I/O accesses to
the hardware which are done exclusively during read, write and clock
divider configuration.

This ensures that the register space is accessible, and this also
ensures that there are not unnecessarily elevated reference counts
keeping the clocks active when the network device is administratively
turned off. It would be the case with the previous way of managing the
clock.

Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add support for scanning PHY in PHY package nodes. PHY packages nodes
are just container for actual PHY on the MDIO bus.

Their PHY address defined in the PHY package node are absolute and
reflect the address on the MDIO bus.

mdio_bus.c and of_mdio.c is updated to now support and parse also
PHY package subnode by checking if the node name match
"ethernet-phy-package".

As PHY package reg is mandatory and each PHY in the PHY package must
have a reg, every invalid PHY Package node is ignored and will be
skipped by the autoscan fallback.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

The IPQ4019 MDIO internally divide the clock feed by AHB based on the
MDIO_MODE reg. On reset or power up, the default value for the
divider is 0xff that reflect the divider set to /256.

This makes the MDC run at a very low rate, that is, considering AHB is
always fixed to 100Mhz, a value of 390KHz.

This hasn't have been a problem as MDIO wasn't used for time sensitive
operation, it is now that on IPQ807x is usually mounted with PHY that
requires MDIO to load their firmware (example Aquantia PHY).

To handle this problem and permit to set the correct designed MDC
frequency for the SoC add support for the standard "clock-frequency"
property for the MDIO node.

The divider supports value from /1 to /256 and the common value are to
set it to /16 to reflect 6.25Mhz or to /8 on newer platform to reflect
12.5Mhz.

To scan if the requested rate is supported by the divider, loop with
each supported divider and stop when the requested rate match the final
rate with the current divider. An error is returned if the rate doesn't
match any value.

On MDIO reset, the divider is restored to the requested value to prevent
any kind of downclocking caused by the divider reverting to a default
value.

To follow 802.3 spec of 2.5MHz of default value, if divider is set at
/256 and "clock-frequency" is not set in DT, assume nobody set the
divider and try to find the closest MDC rate to 2.5MHz. (in the case of
AHB set to 100MHz, it's 1.5625MHz)

While at is also document other bits of the MDIO_MODE reg to have a
clear idea of what is actually applied there.

Documentation of some BITs is skipped as they are marked as reserved and
their usage is not clear (RES 11:9 GENPHY 16:13 RES1 19:17)

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

Instead of open coding, use IS_ALIGNED() and ALIGN_DOWN() when dealing
with alignment. Replace also literals with SZ_4K.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Acked-by: Ray Jui <ray.jui@broadcom.com>
Link: https://lore.kernel.org/r/20231229145232.6163-1-ilpo.jarvinen@linux.intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This reverts commit cff9c565e65f3622e8dc1dcc21c1520a083dff35.

Revert based on feedback from Russell.

Link: https://lore.kernel.org/all/ZZPtUIRerqTI2%2Fyh@shell.armlinux.org.uk/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

The __of_mdiobus_register() function was storing the device node in
dev.of_node without increasing its reference count. It implicitly relied
on the caller to maintain the allocated node until the mdiobus was
unregistered.

Now, __of_mdiobus_register() will acquire the node before assigning it,
and of_mdiobus_unregister_callback() will be called at the end of
mdio_unregister().

Drivers can now release the node immediately after MDIO registration.
Some of them are already doing that even before this patch.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

After the mii_bus API conversion to a split read() / read_c45(), there
might be MDIO parent buses which only populate the read_c45() and
write_c45() function pointers but not the C22 variants.

We haven't seen these in the wild paired with MDIO multiplexers, but
Andrew points out we should treat the corner case.

Link: https://lore.kernel.org/netdev/4ccd7dc9-b611-48aa-865f-68d3a1327ce8@lunn.ch/
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20231213152712.320842-3-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Showing the precise error symbols can help debugging probe issues, such
as the recent -EIO error in of_mdiobus_register() caused by the lack of
bus->read_c45() and bus->write_c45() methods.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20231213152712.320842-2-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Simplify the code by using read_poll_timeout().

Signed-off-by: Justin Chen <justin.chen@broadcom.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20231213222744.2891184-3-justin.chen@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>