The XPCS expects clause 73 (copper backplane) autoneg to follow the
ethtool autoneg bit. It actually did that until the blamed
commit inaptly replaced state->an_enabled (coming from ethtool) with
phylink_autoneg_inband() (coming from the device tree or struct
phylink_config), as part of an unrelated phylink_pcs API conversion.
Russell King suggests that state->an_enabled from the original code was
just a proxy for the ethtool Autoneg bit, and that the correct way of
restoring the functionality is to check for this bit in the advertising
mask.
Fixes: 11059740e6 ("net: pcs: xpcs: convert to phylink_pcs_ops")
Link: https://lore.kernel.org/netdev/ZGNt2MFeRolKGFck@shell.armlinux.org.uk/
Suggested-by: Russell King (Oracle) <linux@armlinux.org.uk>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In synopsys_xpcs_compat[], the DW_XPCS_2500BASEX entry was setting
the number of interfaces using the xpcs_2500basex_features array
rather than xpcs_2500basex_interfaces. This causes us to overflow
the array of interfaces. Fix this.
Fixes: f27abde304 ("net: pcs: add 2500BASEX support for Intel mGbE controller")
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The Autoneg bit in the advertising bitmap and state->an_enabled are
always identical. Thus, we will be removing state->an_enabled.
Use the Autoneg bit in the advertising bitmap to indicate whether
autonegotiation should be used, rather than using the an_enabled
member which will be going away.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The SGMII core found in several MediaTek SoCs is identical to what can
also be found in MediaTek's MT7531 Ethernet switch IC.
As this has not always been clear, both drivers developed different
implementations to deal with the PCS.
Recently Alexander Couzens pointed out this fact which lead to the
development of this shared driver.
Add a dedicated driver, mostly by copying the code now found in the
Ethernet driver. The now redundant code will be removed by a follow-up
commit.
Suggested-by: Alexander Couzens <lynxis@fe80.eu>
Suggested-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Tested-by: Frank Wunderlich <frank-w@public-files.de>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
an_enabled will be going away, and in any case, pcs_get_state() should
not be updating this member. Remove the print.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Steen Hegelund <Steen.Hegelund@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Phylink does not want the current state of the link when reading the
PCS link state - it wants the latched state. Don't double-read the
MII status register. Phylink will re-read as necessary to capture
transient link-down events as of dbae3388ea ("net: phylink: Force
retrigger in case of latched link-fail indicator").
The above referenced commit is a dependency for this change, and thus
this change should not be backported to any kernel that does not
contain the above referenced commit.
Fixes: fcb26bd2b6 ("net: phy: Add Synopsys DesignWare XPCS MDIO module")
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use the phylink_get_link_timer_ns() helper to get the period for the
link timer.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/E1pFyhW-0067jq-Fh@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Convert the PCS-XPCS driver to make use of the C45 MDIO bus API for
modify_change().
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
remove unused register definitions, left from the split with the
altera-tse mac driver.
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When disabling the SGMII mode bit, the PCS defaults to 1000BaseX mode.
In that mode, we don't need to set the speed since it's always 1000Mbps.
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Software resets on the TSE PCS don't clear registers, but rather reset
all internal state machines regarding AN, comma detection and
encoding/decoding. Use read_poll_timeout to wait for the reset to clear
instead of manually polling the register.
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Use mdiodev accessors rather than accessing the bus and address in
the mdio_device structure and using the mdiobus accessors.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The Altera Triple Speed Ethernet has a SGMII/1000BaseC PCS that can be
integrated in several ways. It can either be part of the TSE MAC's
address space, accessed through 32 bits accesses on the mapped mdio
device 0, or through a dedicated 16 bits register set.
This driver allows using the TSE PCS outside of altera TSE's driver,
since it can be used standalone by other MACs.
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While phylink_pcs_ops :: pcs_get_state does return void, xpcs_get_state()
does check for a non-zero return code from xpcs_get_state_c37_sgmii()
and prints that as a message to the kernel log.
However, a non-zero return code from xpcs_read() is translated into
"return false" (i.e. zero as int) and the I/O error is therefore not
printed. Fix that.
Fixes: b97b5331b8 ("net: pcs: add C37 SGMII AN support for intel mGbE controller")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20220720112057.3504398-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
As stated by Russel King, miic_config() can be called as a result of
ethtool setting the configuration while the link is already up. Since
the speed is also set in this function, it could potentially modify
the current speed that is set. This will only happen if there is
no PHY present and we aren't using fixed-link mode.
Handle that by storing the current interface mode in the miic_port
structure and update the speed only if the interface mode is going to
be changed.
Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Link: https://lore.kernel.org/r/20220629122003.189397-1-clement.leger@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
On failure, devm_platform_ioremap_resource() returns a ERR_PTR() value
and not NULL. Fix return value checking by using IS_ERR() and return
PTR_ERR() as error value.
Fixes: 7dc54d3b8d ("net: pcs: add Renesas MII converter driver")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Clément Léger <clement.leger@bootlin.com>
Link: https://lore.kernel.org/r/20220628131259.3109124-1-yangyingliang@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add a PCS driver for the MII converter that is present on the Renesas
RZ/N1 SoC. This MII converter is reponsible for converting MII to
RMII/RGMII or act as a MII pass-trough. Exposing it as a PCS allows to
reuse it in both the switch driver and the stmmac driver. Currently,
this driver only allows the PCS to be used by the dual Cortex-A7
subsystem since the register locking system is not used.
Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Consolidate lynx_pcs_config_1000basex() and lynx_pcs_config_sgmii() into
a single function. The differences between these two are:
- The value that the link timer is set to.
- The value of the IF_MODE register.
Everything else is identical.
This patch depends on "net: phylink: add QSGMII support to
phylink_mii_c22_pcs_encode_advertisement()".
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Tested-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Reviewed-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Use the newly introduced mii_bmcr_encode_fixed() for the xpcs driver.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
For CL37 1000BASE-X AN, DW xPCS does not support C22 method but offers
C45 vendor-specific MII MMD for programming.
We also add the ability to disable Autoneg (through ethtool for certain
network switch that supports 1000BASE-X (1000Mbps and Full-Duplex) but
not Autoneg capability.
v4: Fixes to comment from Russell King. Thanks!
https://patchwork.kernel.org/comment/24894239/
Make xpcs_modify_changed() as private, change to use
mdiodev_modify_changed() for cleaner code.
v3: Fixes to issues spotted by Russell King. Thanks!
https://patchwork.kernel.org/comment/24890210/
Use phylink_mii_c22_pcs_decode_state(), remove unnecessary
interrupt clearing and skip speed & duplex setting if AN
is enabled.
v2: Fixes to issues spotted by Russell King in v1. Thanks!
https://patchwork.kernel.org/comment/24826650/
Use phylink_mii_c22_pcs_encode_advertisement() and implement
C45 MII ADV handling since IP only support C45 access.
Tested-by: Emilio Riva <emilio.riva@ericsson.com>
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
xpcs_config() has 'advertising' input that is required for C37 1000BASE-X
AN in later patch series. So, we prepare xpcs_do_config() for it.
For sja1105, xpcs_do_config() is used for xpcs configuration without
depending on advertising input, so set to NULL.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stop using the helpers to construct a special mdio address which
indicates C45. Instead use the C45 accessors, which will call the
busses C45 specific read/write API.
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
stmmac explicitly calls the xpcs driver to validate the ethtool
linkmodes. This is no longer necessary as phylink now supports
validation through a PCS method. Convert both drivers to use this
new mechanism.
Tested-by: Wong Vee Khee <vee.khee.wong@linux.intel.com> # Intel EHL
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a function to the xpcs driver to retrieve the supported PHY
interface modes, which can be used by drivers to fill in phylink's
supported_interfaces mask.
We validate the interface bit index to ensure that it fits within the
bitmap as xpcs lists PHY_INTERFACE_MODE_MAX in an entry.
Tested-by: Wong Vee Khee <vee.khee.wong@linux.intel.com> # Intel EHL Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
pcs-lynx.c used lynx_pcs and lynx as a variable name within the same file.
This standardizes all internal variables to just "lynx"
Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove references to lynx_pcs structures so drivers like the Felix DSA
can reference alternate PCS drivers.
Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When Energy-Efficient Ethernet(EEE) is disable from the MAC side,
we need to clear the DW_VR_MII_EEE_TRN_LPI bit of DW_VR_MII_EEE_MCTRL1
register.
Fixes: 7617af3d1a ("net: pcs: Introducing support for DWC xpcs Energy Efficient Ethernet")
Cc: Michael Sit Wei Hong <michael.wei.hong.sit@intel.com>
Signed-off-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
According to Synopsys DesignWare Cores Ethernet PCS databook, it is
required to disable Clause 37 auto-negotiation by programming bit-12
(AN_ENABLE) to 0 if it is already enabled, before programming various
fields of VR_MII_AN_CTRL registers.
After all these programming are done, it is then required to enable
Clause 37 auto-negotiation by programming bit-12 (AN_ENABLE) to 1.
Fixes: b97b5331b8 ("net: pcs: add C37 SGMII AN support for intel mGbE controller")
Cc: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
NXP Legal insists that the following are not fine:
- Saying "NXP Semiconductors" instead of "NXP", since the company's
registered name is "NXP"
- Putting a "(c)" sign in the copyright string
- Putting a comma in the copyright string
The only accepted copyright string format is "Copyright <year-range> NXP".
This patch changes the copyright headers in the networking files that
were sent by me, or derived from code sent by me.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
SGMII/2500BaseX supports Pause frame as defined in the IEEE802.3x
Flow Control standardization.
Add this as a supported feature under the xpcs_sgmii_features struct.
Cc: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Drivers such as sja1105 and stmmac that call xpcs_create() expects an
error returned by the pcs-xpcs module, but this was not the case on
failed to allocate memory.
Fixed this by returning an -ENOMEM instead of a NULL pointer.
Fixes: 3ad1d17154 ("net: dsa: sja1105: migrate to xpcs for SGMII")
Signed-off-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20210810085812.1808466-1-vee.khee.wong@linux.intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Currently the check for the u16 variable val being less than zero is
always false because val is unsigned. Fix this by using the int
variable for the assignment and less than zero check.
Addresses-Coverity: ("Unsigned compared against 0")
Fixes: f7380bba42 ("net: pcs: xpcs: add support for NXP SJA1110")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The sja1105 hardware has a quirk in that some changes require a switch
reset, which loses all configuration. When the reset is initiated,
everything needs to be reprogrammed, including the MACs and the PCS.
This is currently done in sja1105_static_config_reload() - we manually
call sja1105_adjust_port_config(), sja1105_sgmii_pcs_config() and
sja1105_sgmii_pcs_force_speed() which are all internal functions.
There is a desire for sja1105 to use the common xpcs driver, and that
means that the equivalents of those functions, xpcs_do_config() and
xpcs_link_up() respectively, will no longer be local functions.
Forcing phylink to retrigger a resolve somehow, say by doing dev_close()
followed by dev_open() is not really an option, because the CPU port
might have a PCS as well, and there is no net device which we can close
and reopen for that. Additionally, the dev_close/dev_open sequence might
force a renegotiation of the copper-side link for SGMII ports connected
to a PHY, and this is undesirable as well, because the switch reset is
much quicker than a PHY autoneg, so we would have a lot more downtime.
The only solution I see is for the sja1105 driver to keep doing what
it's doing, and that means we need to export the equivalents from xpcs
for sja1105_sgmii_pcs_config and sja1105_sgmii_pcs_force_speed, and call
them directly in sja1105_static_config_reload(). This will be done
during the conversion patch.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The NXP SJA1110 switch integrates its own, non-Synopsys PMA, but it
manages it through the register space of the XPCS itself, in a small
register window inside MDIO_MMD_VEND2 from address 0x8030 to 0x806e.
This coincides with where the registers for the default Synopsys PMA
are, but the register definitions are of course not the same.
This situation is an odd hardware quirk, but the simplest way to manage
it is to drive the SJA1110's PMA from within the XPCS driver.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The NXP SJA1105 DSA switch integrates a Synopsys SGMII XPCS on port 4.
The generic code works fine, except there is an integration issue which
needs to be dealt with: in this switch, the XPCS is integrated with a
PMA that has the TX lane polarity inverted by default (PLUS is MINUS,
MINUS is PLUS).
To obtain normal non-inverted behavior, the TX lane polarity must be
inverted in the PCS, via the DIGITAL_CONTROL_2 register.
We introduce a pma_config() method in xpcs_compat which is called by the
phylink_pcs_config() implementation.
Also, the NXP SJA1105 returns all zeroes in the PHY ID registers 2 and 3.
We need to hack up an ad-hoc PHY ID (OUI is zero, device ID is 1) in
order for the XPCS driver to recognize it. This PHY ID is added to the
public include/linux/pcs/pcs-xpcs.h for that reason (for the sja1105
driver to be able to use it in a later patch).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
xpcs_get_id() searches multiple MMDs for a known PHY ID, starting with
MDIO_MMD_PCS (3). However not all integrators might have implemented
that MMD on their MDIO bus. For example, the NXP SJA1105 and SJA1110
switches only implement vendor-specific MMD 1 and 2.
When there is nothing on an MDIO bus at a certain address, traditionally
the bus returns 0xffff, which means that the bus remained in its default
pull-up state for the duration of the MDIO transaction. The 0xffff value
is widely used in drivers/net/phy/phy_device.c (see get_phy_c22_id for
example) to denote a missing device.
So it makes sense for the xpcs to ignore this value as well, and
continue its search, eventually finding the proper PHY ID in the
vendor-specific MMDs.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In fixed-link use cases, the XPCS can disable the clause 37 in-band
autoneg process, disable the "Automatic Speed Mode Change after CL37 AN"
setting, and force operation in a speed dictated by management.
Add support for this operating mode.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Vendors which integrate the Designware XPCS might modify a few things
here and there, and to support those, it's best to create separate C
files in order to not clutter up the main pcs-xpcs.c.
Because the vendor files might want to access the common xpcs registers
too, let's move them in a header file which is local to this driver and
can be included by vendor files as appropriate.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The struct mdio_xpcs_args is reminiscent of when a similarly named
struct mdio_xpcs_ops existed. Now that that is removed, we can shorten
the name to dw_xpcs (dw for DesignWare).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
XPCS IP supports 2500BASEX as PHY interface. It is configured as
autonegotiation disable to cater for PHYs that does not supports 2500BASEX
autonegotiation.
v2: Add supported link speed masking.
v3: Restructure to introduce xpcs_config_2500basex() used to configure the
xpcs for 2.5G speeds. Added 2500BASEX specific information for
configuration.
v4: Fix indentation error
Signed-off-by: Voon Weifeng <weifeng.voon@intel.com>
Signed-off-by: Michael Sit Wei Hong <michael.wei.hong.sit@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since all the remaining members of struct mdio_xpcs_ops have direct
equivalents in struct phylink_pcs_ops, it is about time we remove it
altogether.
Since the phylink ops return void, we need to remove the error
propagation from the various xpcs methods and simply print an error
message where appropriate.
Since xpcs_get_state_c73() detects link faults and attempts to reset the
link on its own by calling xpcs_config(), but xpcs_config() now has a
lot of phylink arguments which are not needed and cannot be simply
fabricated by anybody else except phylink, the actual implementation has
been moved into a smaller xpcs_do_config().
The const struct mdio_xpcs_ops *priv->hw->xpcs has been removed, so we
need to look at the struct mdio_xpcs_args pointer now as an indication
whether the port has an XPCS or not.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Unify the 2 existing PCS drivers (lynx and xpcs) by doing a similar
thing on probe, which is to have a *_create function that takes a
struct mdio_device * given by the caller, and builds a private PCS
structure around that.
This changes stmmac to hold only a pointer to the xpcs, as opposed to
the full structure. This will be used in the next patch when struct
mdio_xpcs_ops is removed. Currently a pointer to struct mdio_xpcs_ops
is used as a shorthand to determine whether the port has an XPCS or not.
We can do the same now with the mdio_xpcs_args pointer.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use the dedicated helper for abstracting away how the clause 45 address
is packed in reg_addr.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Similar to the other recently functions, it is not necessary for
xpcs_probe to be a function pointer, so export it so that it can be
called directly.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is no good reason why we need to go through:
stmmac_xpcs_config_eee
-> stmmac_do_callback
-> mdio_xpcs_ops->config_eee
-> xpcs_config_eee
when we can simply call xpcs_config_eee.
priv->hw->xpcs is of the type "const struct mdio_xpcs_ops *" and is used
as a placeholder/synonym for priv->plat->mdio_bus_data->has_xpcs. It is
done that way because the mdio_bus_data pointer might or might not be
populated in all stmmac instantiations.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>