<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/drivers/net/phy, branch v5.15-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Revert "net: phy: Uniform PHY driver access"</title>
<updated>2021-09-15T22:06:46+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2021-09-14T14:05:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=301de697d869be6564aebeb5ab811c84c0a7abed'/>
<id>301de697d869be6564aebeb5ab811c84c0a7abed</id>
<content type='text'>
This reverts commit 3ac8eed62596387214869319379c1fcba264d8c6, which did
more than it said on the box, and not only it replaced to_phy_driver
with phydev-&gt;drv, but it also removed the "!drv" check, without actually
explaining why that is fine.

That patch in fact breaks suspend/resume on any system which has PHY
devices with no drivers bound.

The stack trace is:

Unable to handle kernel NULL pointer dereference at virtual address 00000000000000e8
pc : mdio_bus_phy_suspend+0xd8/0xec
lr : dpm_run_callback+0x38/0x90
Call trace:
 mdio_bus_phy_suspend+0xd8/0xec
 dpm_run_callback+0x38/0x90
 __device_suspend+0x108/0x3cc
 dpm_suspend+0x140/0x210
 dpm_suspend_start+0x7c/0xa0
 suspend_devices_and_enter+0x13c/0x540
 pm_suspend+0x2a4/0x330

Examples why that assumption is not fine:

- There is an MDIO bus with a PHY device that doesn't have a specific
  PHY driver loaded, because mdiobus_register() automatically creates a
  PHY device for it but there is no specific PHY driver in the system.
  Normally under those circumstances, the generic PHY driver will be
  bound lazily to it (at phy_attach_direct time). But some Ethernet
  drivers attach to their PHY at .ndo_open time. Until then it, the
  to-be-driven-by-genphy PHY device will not have a driver. The blamed
  patch amounts to saying "you need to open all net devices before the
  system can suspend, to avoid the NULL pointer dereference".

- There is any raw MDIO device which has 'plausible' values in the PHY
  ID registers 2 and 3, which is located on an MDIO bus whose driver
  does not set bus-&gt;phy_mask = ~0 (which prevents auto-scanning of PHY
  devices). An example could be a MAC's internal MDIO bus with PCS
  devices on it, for serial links such as SGMII. PHY devices will get
  created for those PCSes too, due to that MDIO bus auto-scanning, and
  although those PHY devices are not used, they do not bother anybody
  either. PCS devices are usually managed in Linux as raw MDIO devices.
  Nonetheless, they do not have a PHY driver, nor does anybody attempt
  to connect to them (because they are not a PHY), and therefore this
  patch breaks that.

The goal itself of the patch is questionable, so I am going for a
straight revert. to_phy_driver does not seem to have a need to be
replaced by phydev-&gt;drv, in fact that might even trigger code paths
which were not given too deep of a thought.

For instance:

phy_probe populates phydev-&gt;drv at the beginning, but does not clean it
up on any error (including EPROBE_DEFER). So if the phydev driver
requests probe deferral, phydev-&gt;drv will remain populated despite there
being no driver bound.

If a system suspend starts in between the initial probe deferral request
and the subsequent probe retry, we will be calling the phydev-&gt;drv-&gt;suspend
method, but _before_ any phydev-&gt;drv-&gt;probe call has succeeded.

That is to say, if the phydev-&gt;drv is allocating any driver-private data
structure in -&gt;probe, it pretty much expects that data structure to be
available in -&gt;suspend. But it may not. That is a pretty insane
environment to present to PHY drivers.

In the code structure before the blamed patch, mdio_bus_phy_may_suspend
would just say "no, don't suspend" to any PHY device which does not have
a driver pointer _in_the_device_structure_ (not the phydev-&gt;drv). That
would essentially ensure that -&gt;suspend will never get called for a
device that has not yet successfully completed probe. This is the code
structure the patch is returning to, via the revert.

Fixes: 3ac8eed62596 ("net: phy: Uniform PHY driver access")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Acked-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Link: https://lore.kernel.org/r/20210914140515.2311548-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This reverts commit 3ac8eed62596387214869319379c1fcba264d8c6, which did
more than it said on the box, and not only it replaced to_phy_driver
with phydev-&gt;drv, but it also removed the "!drv" check, without actually
explaining why that is fine.

That patch in fact breaks suspend/resume on any system which has PHY
devices with no drivers bound.

The stack trace is:

Unable to handle kernel NULL pointer dereference at virtual address 00000000000000e8
pc : mdio_bus_phy_suspend+0xd8/0xec
lr : dpm_run_callback+0x38/0x90
Call trace:
 mdio_bus_phy_suspend+0xd8/0xec
 dpm_run_callback+0x38/0x90
 __device_suspend+0x108/0x3cc
 dpm_suspend+0x140/0x210
 dpm_suspend_start+0x7c/0xa0
 suspend_devices_and_enter+0x13c/0x540
 pm_suspend+0x2a4/0x330

Examples why that assumption is not fine:

- There is an MDIO bus with a PHY device that doesn't have a specific
  PHY driver loaded, because mdiobus_register() automatically creates a
  PHY device for it but there is no specific PHY driver in the system.
  Normally under those circumstances, the generic PHY driver will be
  bound lazily to it (at phy_attach_direct time). But some Ethernet
  drivers attach to their PHY at .ndo_open time. Until then it, the
  to-be-driven-by-genphy PHY device will not have a driver. The blamed
  patch amounts to saying "you need to open all net devices before the
  system can suspend, to avoid the NULL pointer dereference".

- There is any raw MDIO device which has 'plausible' values in the PHY
  ID registers 2 and 3, which is located on an MDIO bus whose driver
  does not set bus-&gt;phy_mask = ~0 (which prevents auto-scanning of PHY
  devices). An example could be a MAC's internal MDIO bus with PCS
  devices on it, for serial links such as SGMII. PHY devices will get
  created for those PCSes too, due to that MDIO bus auto-scanning, and
  although those PHY devices are not used, they do not bother anybody
  either. PCS devices are usually managed in Linux as raw MDIO devices.
  Nonetheless, they do not have a PHY driver, nor does anybody attempt
  to connect to them (because they are not a PHY), and therefore this
  patch breaks that.

The goal itself of the patch is questionable, so I am going for a
straight revert. to_phy_driver does not seem to have a need to be
replaced by phydev-&gt;drv, in fact that might even trigger code paths
which were not given too deep of a thought.

For instance:

phy_probe populates phydev-&gt;drv at the beginning, but does not clean it
up on any error (including EPROBE_DEFER). So if the phydev driver
requests probe deferral, phydev-&gt;drv will remain populated despite there
being no driver bound.

If a system suspend starts in between the initial probe deferral request
and the subsequent probe retry, we will be calling the phydev-&gt;drv-&gt;suspend
method, but _before_ any phydev-&gt;drv-&gt;probe call has succeeded.

That is to say, if the phydev-&gt;drv is allocating any driver-private data
structure in -&gt;probe, it pretty much expects that data structure to be
available in -&gt;suspend. But it may not. That is a pretty insane
environment to present to PHY drivers.

In the code structure before the blamed patch, mdio_bus_phy_may_suspend
would just say "no, don't suspend" to any PHY device which does not have
a driver pointer _in_the_device_structure_ (not the phydev-&gt;drv). That
would essentially ensure that -&gt;suspend will never get called for a
device that has not yet successfully completed probe. This is the code
structure the patch is returning to, via the revert.

Fixes: 3ac8eed62596 ("net: phy: Uniform PHY driver access")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Acked-by: Florian Fainelli &lt;f.fainelli@gmail.com&gt;
Link: https://lore.kernel.org/r/20210914140515.2311548-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ptp: dp83640: don't define PAGE0</title>
<updated>2021-09-15T03:03:24+00:00</updated>
<author>
<name>Randy Dunlap</name>
<email>rdunlap@infradead.org</email>
</author>
<published>2021-09-13T22:06:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7366c23ff492ad260776a3ee1aaabba9fc773a8b'/>
<id>7366c23ff492ad260776a3ee1aaabba9fc773a8b</id>
<content type='text'>
Building dp83640.c on arch/parisc/ produces a build warning for
PAGE0 being redefined. Since the macro is not used in the dp83640
driver, just make it a comment for documentation purposes.

In file included from ../drivers/net/phy/dp83640.c:23:
../drivers/net/phy/dp83640_reg.h:8: warning: "PAGE0" redefined
    8 | #define PAGE0                     0x0000
                 from ../drivers/net/phy/dp83640.c:11:
../arch/parisc/include/asm/page.h:187: note: this is the location of the previous definition
  187 | #define PAGE0   ((struct zeropage *)__PAGE_OFFSET)

Fixes: cb646e2b02b2 ("ptp: Added a clock driver for the National Semiconductor PHYTER.")
Signed-off-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Reported-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Richard Cochran &lt;richard.cochran@omicron.at&gt;
Cc: John Stultz &lt;john.stultz@linaro.org&gt;
Cc: Heiner Kallweit &lt;hkallweit1@gmail.com&gt;
Cc: Russell King &lt;linux@armlinux.org.uk&gt;
Reviewed-by: Andrew Lunn &lt;andrew@lunn.ch&gt;
Link: https://lore.kernel.org/r/20210913220605.19682-1-rdunlap@infradead.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Building dp83640.c on arch/parisc/ produces a build warning for
PAGE0 being redefined. Since the macro is not used in the dp83640
driver, just make it a comment for documentation purposes.

In file included from ../drivers/net/phy/dp83640.c:23:
../drivers/net/phy/dp83640_reg.h:8: warning: "PAGE0" redefined
    8 | #define PAGE0                     0x0000
                 from ../drivers/net/phy/dp83640.c:11:
../arch/parisc/include/asm/page.h:187: note: this is the location of the previous definition
  187 | #define PAGE0   ((struct zeropage *)__PAGE_OFFSET)

Fixes: cb646e2b02b2 ("ptp: Added a clock driver for the National Semiconductor PHYTER.")
Signed-off-by: Randy Dunlap &lt;rdunlap@infradead.org&gt;
Reported-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Richard Cochran &lt;richard.cochran@omicron.at&gt;
Cc: John Stultz &lt;john.stultz@linaro.org&gt;
Cc: Heiner Kallweit &lt;hkallweit1@gmail.com&gt;
Cc: Russell King &lt;linux@armlinux.org.uk&gt;
Reviewed-by: Andrew Lunn &lt;andrew@lunn.ch&gt;
Link: https://lore.kernel.org/r/20210913220605.19682-1-rdunlap@infradead.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: phylink: Update SFP selected interface on advertising changes</title>
<updated>2021-09-08T11:02:19+00:00</updated>
<author>
<name>Nathan Rossi</name>
<email>nathan.rossi@digi.com</email>
</author>
<published>2021-09-02T05:14:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ea269a6f720782ed94171fb962b14ce07c372138'/>
<id>ea269a6f720782ed94171fb962b14ce07c372138</id>
<content type='text'>
Currently changes to the advertising state via ethtool do not cause any
reselection of the configured interface mode after the SFP is already
inserted and initially configured.

While it is not typical to change the advertised link modes for an
interface using an SFP in certain use cases it is desirable. In the case
of a SFP port that is capable of handling both SFP and SFP+ modules it
will automatically select between 1G and 10G modes depending on the
supported mode of the SFP. However if the SFP module is capable of
working in multiple modes (e.g. a SFP+ DAC that can operate at 1G or
10G), one end of the cable may be attached to a SFP 1000base-x port thus
the SFP+ end must be manually configured to the 1000base-x mode in order
for the link to be established.

This change causes the ethtool setting of advertised mode changes to
reselect the interface mode so that the link can be established.
Additionally when a module is inserted the advertising mode is reset to
match the supported modes of the module.

Signed-off-by: Nathan Rossi &lt;nathan.rossi@digi.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently changes to the advertising state via ethtool do not cause any
reselection of the configured interface mode after the SFP is already
inserted and initially configured.

While it is not typical to change the advertised link modes for an
interface using an SFP in certain use cases it is desirable. In the case
of a SFP port that is capable of handling both SFP and SFP+ modules it
will automatically select between 1G and 10G modes depending on the
supported mode of the SFP. However if the SFP module is capable of
working in multiple modes (e.g. a SFP+ DAC that can operate at 1G or
10G), one end of the cable may be attached to a SFP 1000base-x port thus
the SFP+ end must be manually configured to the 1000base-x mode in order
for the link to be established.

This change causes the ethtool setting of advertised mode changes to
reselect the interface mode so that the link can be established.
Additionally when a module is inserted the advertising mode is reset to
match the supported modes of the module.

Signed-off-by: Nathan Rossi &lt;nathan.rossi@digi.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: phylink: add suspend/resume support</title>
<updated>2021-09-07T13:04:59+00:00</updated>
<author>
<name>Russell King (Oracle)</name>
<email>rmk+kernel@armlinux.org.uk</email>
</author>
<published>2021-09-07T10:56:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f97493657c6372eeefe70faadd214bf31488c44e'/>
<id>f97493657c6372eeefe70faadd214bf31488c44e</id>
<content type='text'>
Joakim Zhang reports that Wake-on-Lan with the stmmac ethernet driver broke
when moving the incorrect handling of mac link state out of mac_config().
This reason this breaks is because the stmmac's WoL is handled by the MAC
rather than the PHY, and phylink doesn't cater for that scenario.

This patch adds the necessary phylink code to handle suspend/resume events
according to whether the MAC still needs a valid link or not. This is the
barest minimum for this support.

Reported-by: Joakim Zhang &lt;qiangqing.zhang@nxp.com&gt;
Tested-by: Joakim Zhang &lt;qiangqing.zhang@nxp.com&gt;
Signed-off-by: Russell King (Oracle) &lt;rmk+kernel@armlinux.org.uk&gt;
Signed-off-by: Joakim Zhang &lt;qiangqing.zhang@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Joakim Zhang reports that Wake-on-Lan with the stmmac ethernet driver broke
when moving the incorrect handling of mac link state out of mac_config().
This reason this breaks is because the stmmac's WoL is handled by the MAC
rather than the PHY, and phylink doesn't cater for that scenario.

This patch adds the necessary phylink code to handle suspend/resume events
according to whether the MAC still needs a valid link or not. This is the
barest minimum for this support.

Reported-by: Joakim Zhang &lt;qiangqing.zhang@nxp.com&gt;
Tested-by: Joakim Zhang &lt;qiangqing.zhang@nxp.com&gt;
Signed-off-by: Russell King (Oracle) &lt;rmk+kernel@armlinux.org.uk&gt;
Signed-off-by: Joakim Zhang &lt;qiangqing.zhang@nxp.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net</title>
<updated>2021-08-31T16:06:04+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2021-08-31T16:06:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=29ce8f9701072fc221d9c38ad952de1a9578f95c'/>
<id>29ce8f9701072fc221d9c38ad952de1a9578f95c</id>
<content type='text'>
include/linux/netdevice.h
net/socket.c

  d0efb16294d1 ("net: don't unconditionally copy_from_user a struct ifreq for socket ioctls")

  876f0bf9d0d5 ("net: socket: simplify dev_ifconf handling")
  29c4964822aa ("net: socket: rework compat_ifreq_ioctl()")

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
include/linux/netdevice.h
net/socket.c

  d0efb16294d1 ("net: don't unconditionally copy_from_user a struct ifreq for socket ioctls")

  876f0bf9d0d5 ("net: socket: simplify dev_ifconf handling")
  29c4964822aa ("net: socket: rework compat_ifreq_ioctl()")

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: phy: marvell10g: fix broken PHY interrupts for anyone after us in the driver probe list</title>
<updated>2021-08-28T00:27:42+00:00</updated>
<author>
<name>Vladimir Oltean</name>
<email>vladimir.oltean@nxp.com</email>
</author>
<published>2021-08-27T13:25:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=0d55649d2ad7296acfda9127e1d05518d025734a'/>
<id>0d55649d2ad7296acfda9127e1d05518d025734a</id>
<content type='text'>
Enabling interrupts via device tree for the internal PHYs on the
mv88e6390 DSA switch does not work. The driver insists to use poll mode.

Stage one debugging shows that the fwnode_mdiobus_phy_device_register
function calls fwnode_irq_get properly, and phy-&gt;irq is set to a valid
interrupt line initially.

But it is then cleared.

Stage two debugging shows that it is cleared here:

phy_probe:

  /* Disable the interrupt if the PHY doesn't support it
   * but the interrupt is still a valid one
   */
  if (!phy_drv_supports_irq(phydrv) &amp;&amp; phy_interrupt_is_valid(phydev))
	phydev-&gt;irq = PHY_POLL;

Okay, so does the "Marvell 88E6390 Family" PHY driver not have the
.config_intr and .handle_interrupt function pointers? Yes it does.

Stage three debugging shows that the PHY device does not attempt a probe
against the "Marvell 88E6390 Family" driver, but against the "mv88x3310"
driver.

Okay, so why does the "mv88x3310" driver match on a mv88x6390 internal
PHY? The PHY IDs (MARVELL_PHY_ID_88E6390_FAMILY vs
MARVELL_PHY_ID_88X3310) are way different.

Stage four debugging has us looking through:

phy_device_register
-&gt; device_add
   -&gt; bus_probe_device
      -&gt; device_initial_probe
         -&gt; __device_attach
            -&gt; bus_for_each_drv
               -&gt; driver_match_device
                  -&gt; drv-&gt;bus-&gt;match
                     -&gt; phy_bus_match

Okay, so as we said, the MII_PHYSID1 of mv88e6390 does not match the
mv88x3310 driver's PHY mask &amp; ID, so why would phy_bus_match return...

Ahh, phy_bus_match calls a shortcircuit method,
phydrv-&gt;match_phy_device, and does not even bother to compare the PHY ID
if that is implemented.

So of course, we go inside the marvell10g.c driver and sure enough, it
implements .match_phy_device and does not bother to check the PHY ID.

What's interesting though is that at the end of the device_add() from
phy_device_register(), the driver for the internal PHYs _is_ the proper
"Marvell 88E6390 Family". This is because "mv88x3310" ends up failing to
probe after all, and __device_attach_driver(), to quote:

  /*
   * Ignore errors returned by -&gt;probe so that the next driver can try
   * its luck.
   */

The next (and only other) driver that matches is the 6390 driver. For
this one, phy_probe doesn't fail, and everything expects to work as
normal, EXCEPT phydev-&gt;irq has already been cleared by the previous
unsuccessful probe of a driver which did not implement PHY interrupts,
and therefore cleared that IRQ.

Okay, so it is not just Marvell 6390 that has PHY interrupts broken.
Stuff like Atheros, Aquantia, Broadcom, Qualcomm work because they are
lexicographically before Marvell, and stuff like NXP, Realtek, Vitesse
are broken.

This goes to show how fragile it is to reset phydev-&gt;irq = PHY_POLL from
the actual beginning of phy_probe itself. That seems like an actual bug
of its own too, since phy_probe has side effects which are not restored
on probe failure, but the line of thought probably was, the same driver
will attempt probe again, so it doesn't matter. Well, looks like it
does.

Maybe it would make more sense to move the phydev-&gt;irq clearing after
the actual device_add() in phy_device_register() completes, and the
bound driver is the actual final one.

(also, a bit frightening that drivers are permitted to bypass the MDIO
bus matching in such a trivial way and perform PHY reads and writes from
the .match_phy_device method, on devices that do not even belong to
them. In the general case it might not be guaranteed that the MDIO
accesses one driver needs to make to figure out whether to match on a
device is safe for all other PHY devices)

Fixes: a5de4be0aaaa ("net: phy: marvell10g: fix differentiation of 88X3310 from 88X3340")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Tested-by: Marek Behún &lt;kabel@kernel.org&gt;
Signed-off-by: Marek Behún &lt;kabel@kernel.org&gt;
Reviewed-by: Andrew Lunn &lt;andrew@lunn.ch&gt;
Link: https://lore.kernel.org/r/20210827132541.28953-1-kabel@kernel.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Enabling interrupts via device tree for the internal PHYs on the
mv88e6390 DSA switch does not work. The driver insists to use poll mode.

Stage one debugging shows that the fwnode_mdiobus_phy_device_register
function calls fwnode_irq_get properly, and phy-&gt;irq is set to a valid
interrupt line initially.

But it is then cleared.

Stage two debugging shows that it is cleared here:

phy_probe:

  /* Disable the interrupt if the PHY doesn't support it
   * but the interrupt is still a valid one
   */
  if (!phy_drv_supports_irq(phydrv) &amp;&amp; phy_interrupt_is_valid(phydev))
	phydev-&gt;irq = PHY_POLL;

Okay, so does the "Marvell 88E6390 Family" PHY driver not have the
.config_intr and .handle_interrupt function pointers? Yes it does.

Stage three debugging shows that the PHY device does not attempt a probe
against the "Marvell 88E6390 Family" driver, but against the "mv88x3310"
driver.

Okay, so why does the "mv88x3310" driver match on a mv88x6390 internal
PHY? The PHY IDs (MARVELL_PHY_ID_88E6390_FAMILY vs
MARVELL_PHY_ID_88X3310) are way different.

Stage four debugging has us looking through:

phy_device_register
-&gt; device_add
   -&gt; bus_probe_device
      -&gt; device_initial_probe
         -&gt; __device_attach
            -&gt; bus_for_each_drv
               -&gt; driver_match_device
                  -&gt; drv-&gt;bus-&gt;match
                     -&gt; phy_bus_match

Okay, so as we said, the MII_PHYSID1 of mv88e6390 does not match the
mv88x3310 driver's PHY mask &amp; ID, so why would phy_bus_match return...

Ahh, phy_bus_match calls a shortcircuit method,
phydrv-&gt;match_phy_device, and does not even bother to compare the PHY ID
if that is implemented.

So of course, we go inside the marvell10g.c driver and sure enough, it
implements .match_phy_device and does not bother to check the PHY ID.

What's interesting though is that at the end of the device_add() from
phy_device_register(), the driver for the internal PHYs _is_ the proper
"Marvell 88E6390 Family". This is because "mv88x3310" ends up failing to
probe after all, and __device_attach_driver(), to quote:

  /*
   * Ignore errors returned by -&gt;probe so that the next driver can try
   * its luck.
   */

The next (and only other) driver that matches is the 6390 driver. For
this one, phy_probe doesn't fail, and everything expects to work as
normal, EXCEPT phydev-&gt;irq has already been cleared by the previous
unsuccessful probe of a driver which did not implement PHY interrupts,
and therefore cleared that IRQ.

Okay, so it is not just Marvell 6390 that has PHY interrupts broken.
Stuff like Atheros, Aquantia, Broadcom, Qualcomm work because they are
lexicographically before Marvell, and stuff like NXP, Realtek, Vitesse
are broken.

This goes to show how fragile it is to reset phydev-&gt;irq = PHY_POLL from
the actual beginning of phy_probe itself. That seems like an actual bug
of its own too, since phy_probe has side effects which are not restored
on probe failure, but the line of thought probably was, the same driver
will attempt probe again, so it doesn't matter. Well, looks like it
does.

Maybe it would make more sense to move the phydev-&gt;irq clearing after
the actual device_add() in phy_device_register() completes, and the
bound driver is the actual final one.

(also, a bit frightening that drivers are permitted to bypass the MDIO
bus matching in such a trivial way and perform PHY reads and writes from
the .match_phy_device method, on devices that do not even belong to
them. In the general case it might not be guaranteed that the MDIO
accesses one driver needs to make to figure out whether to match on a
device is safe for all other PHY devices)

Fixes: a5de4be0aaaa ("net: phy: marvell10g: fix differentiation of 88X3310 from 88X3340")
Signed-off-by: Vladimir Oltean &lt;vladimir.oltean@nxp.com&gt;
Tested-by: Marek Behún &lt;kabel@kernel.org&gt;
Signed-off-by: Marek Behún &lt;kabel@kernel.org&gt;
Reviewed-by: Andrew Lunn &lt;andrew@lunn.ch&gt;
Link: https://lore.kernel.org/r/20210827132541.28953-1-kabel@kernel.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net</title>
<updated>2021-08-27T00:57:57+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2021-08-26T20:45:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=97c78d0af55fff206947a5f2b85b690b5acf28ce'/>
<id>97c78d0af55fff206947a5f2b85b690b5acf28ce</id>
<content type='text'>
drivers/net/wwan/mhi_wwan_mbim.c - drop the extra arg.

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
drivers/net/wwan/mhi_wwan_mbim.c - drop the extra arg.

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: phy: mediatek: add the missing suspend/resume callbacks</title>
<updated>2021-08-24T23:52:43+00:00</updated>
<author>
<name>DENG Qingfang</name>
<email>dqfext@gmail.com</email>
</author>
<published>2021-08-23T04:44:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=93100d6817b05a60f3e1d354932a4fe792f14d08'/>
<id>93100d6817b05a60f3e1d354932a4fe792f14d08</id>
<content type='text'>
Without suspend/resume callbacks, the PHY cannot be powered down/up
administratively.

Fixes: e40d2cca0189 ("net: phy: add MediaTek Gigabit Ethernet PHY driver")
Signed-off-by: DENG Qingfang &lt;dqfext@gmail.com&gt;
Reviewed-by: Andrew Lunn &lt;andrew@lunn.ch&gt;
Link: https://lore.kernel.org/r/20210823044422.164184-1-dqfext@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Without suspend/resume callbacks, the PHY cannot be powered down/up
administratively.

Fixes: e40d2cca0189 ("net: phy: add MediaTek Gigabit Ethernet PHY driver")
Signed-off-by: DENG Qingfang &lt;dqfext@gmail.com&gt;
Reviewed-by: Andrew Lunn &lt;andrew@lunn.ch&gt;
Link: https://lore.kernel.org/r/20210823044422.164184-1-dqfext@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: phy: gmii2rgmii: Support PHY loopback</title>
<updated>2021-08-20T13:31:46+00:00</updated>
<author>
<name>Gerhard Engleder</name>
<email>gerhard@engleder-embedded.com</email>
</author>
<published>2021-08-19T13:11:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ceaeaafc8b6278930d9994e29d6826ee893cea65'/>
<id>ceaeaafc8b6278930d9994e29d6826ee893cea65</id>
<content type='text'>
Configure speed if loopback is used. read_status is not called for
loopback.

Signed-off-by: Gerhard Engleder &lt;gerhard@engleder-embedded.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Configure speed if loopback is used. read_status is not called for
loopback.

Signed-off-by: Gerhard Engleder &lt;gerhard@engleder-embedded.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: phy: Uniform PHY driver access</title>
<updated>2021-08-20T13:31:46+00:00</updated>
<author>
<name>Gerhard Engleder</name>
<email>gerhard@engleder-embedded.com</email>
</author>
<published>2021-08-19T13:11:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3ac8eed62596387214869319379c1fcba264d8c6'/>
<id>3ac8eed62596387214869319379c1fcba264d8c6</id>
<content type='text'>
struct phy_device contains a pointer to the PHY driver and nearly
everywhere this pointer is used to access the PHY driver. Only
mdio_bus_phy_may_suspend() is still using to_phy_driver() instead of the
PHY driver pointer. Uniform PHY driver access by eliminating
to_phy_driver() use in mdio_bus_phy_may_suspend().

Only phy_bus_match() and phy_probe() are still using to_phy_driver(),
because PHY driver pointer is not available there.

Signed-off-by: Gerhard Engleder &lt;gerhard@engleder-embedded.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
struct phy_device contains a pointer to the PHY driver and nearly
everywhere this pointer is used to access the PHY driver. Only
mdio_bus_phy_may_suspend() is still using to_phy_driver() instead of the
PHY driver pointer. Uniform PHY driver access by eliminating
to_phy_driver() use in mdio_bus_phy_may_suspend().

Only phy_bus_match() and phy_probe() are still using to_phy_driver(),
because PHY driver pointer is not available there.

Signed-off-by: Gerhard Engleder &lt;gerhard@engleder-embedded.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
</feed>
