linux-toradex.git/drivers/net/phy/phy.c, branch v5.0

net: phy: fix potential race in the phylib state machine

2019-02-14T17:04:55+00:00

Russell reported the following race in the phylib state machine
(quoting from his mail):

if (phy_polling_mode(phydev) && phy_is_started(phydev))
	phy_queue_state_machine(phydev, PHY_STATE_TIME);

state = PHY_UP
thread 0			thread 1
				phy_disconnect()
				+-phy_is_started()
phy_is_started()                |
				`-phy_stop()
				  +-phydev->state = PHY_HALTED
				  `-phy_stop_machine()
				    `-cancel_delayed_work_sync()
phy_queue_state_machine()
`-mod_delayed_work()

At this point, the phydev->state_queue() has been added back onto the
system workqueue despite phy_stop_machine() having been called and
cancel_delayed_work_sync() called on it.

Fix this by protecting the complete operation in thread 0.

Fixes: 2b3e88ea6528 ("net: phy: improve phy state checking")
Reported-by: Russell King - ARM Linux admin 
Signed-off-by: Heiner Kallweit 
Reviewed-by: Florian Fainelli 
Signed-off-by: David S. Miller

net: phy: don't use locking in phy_is_started

2019-02-14T17:04:55+00:00

Russell suggested to remove the locking from phy_is_started() because
the read is atomic anyway and actually the locking may be more
misleading.

Fixes: 2b3e88ea6528 ("net: phy: improve phy state checking")
Suggested-by: Russell King - ARM Linux admin 
Signed-off-by: Heiner Kallweit 
Reviewed-by: Florian Fainelli 
Signed-off-by: David S. Miller

net: phy: fix interrupt handling in non-started states

2019-02-14T04:44:12+00:00

phylib enables interrupts before phy_start() has been called, and if
we receive an interrupt in a non-started state, the interrupt handler
returns IRQ_NONE. This causes problems with at least one Marvell chip
as reported by Andrew.
Fix this by handling interrupts the same as in phy_mac_interrupt(),
basically always running the phylib state machine. It knows when it
has to do something and when not.
This change allows to handle interrupts gracefully even if they
occur in a non-started state.

Fixes: 2b3e88ea6528 ("net: phy: improve phy state checking")
Reported-by: Andrew Lunn 
Signed-off-by: Heiner Kallweit 
Reviewed-by: Andrew Lunn 
Reviewed-by: Florian Fainelli 
Signed-off-by: David S. Miller

net: phy: fix too strict check in phy_start_aneg

2019-01-15T21:33:44+00:00

When adding checks to detect wrong usage of the phylib API we added
a check to phy_start_aneg() which is too strict. If the phylib
state machine is in state PHY_HALTED we should allow reconfiguring
and restarting aneg, and just don't touch the state.

Fixes: 2b3e88ea6528 ("net: phy: improve phy state checking")
Reported-by: Chris Wilson 
Signed-off-by: Heiner Kallweit 
Tested-by: Chris Wilson 
Reviewed-by: Florian Fainelli 
Signed-off-by: David S. Miller

net: phy: print stack trace in phy_error

2018-12-18T23:11:46+00:00

So far phy_error() silently stops the PHY state machine. If the network
driver doesn't inform about a  MDIO error then the user may wonder why
his network is down. Let's print the stack trace to facilitate search
for the root cause of the error.

Signed-off-by: Heiner Kallweit 
Signed-off-by: David S. Miller

net: phy: improve phy state checking

2018-12-18T23:11:07+00:00

Add helpers phy_is_started() and __phy_is_started() to avoid open-coded
checks whether PHY has been started. To make the check easier move
PHY_HALTED before PHY_UP in enum phy_state. Further improvements:

phy_start_aneg():
Return -EBUSY and print warning if function is called from a non-started
state (DOWN, READY, HALTED). Better check because function is exported
and drivers may use it incorrectly.

phy_interrupt():
Return IRQ_NONE also if state is DOWN or READY. We should never receive
an interrupt in one of these states, but better play safe.

phy_stop():
Just return and print a warning if PHY is in a non-started state.
This warning should help to identify drivers with unbalanced calls to
phy_start() / phy_stop().

phy_state_machine():
Schedule state machine run only if PHY is in a started state.
E.g. if state is READY we don't need the state machine, it will be
started by phy_start().

v2:
- don't use __func__ within phy_warn_state
v3:
- use WARN() instead of printing error message to facilitate debugging

Signed-off-by: Heiner Kallweit 
Reviewed-by: Florian Fainelli 
Signed-off-by: David S. Miller

net: phy: Fix ioctl handler when modifing MII_ADVERTISE

2018-12-06T00:26:16+00:00

When the MII_ADVERTISE register is modified by the IOCTL handler,
phydev->advertising needs recalculating. Use the _mod_ variant of
mii_adv_to_linkmode_adv_t so that bits outside of the advertise
registers are not cleared.

Fixes: c0ec3c273677 ("net: phy: Convert u32 phydev->lp_advertising to linkmode")
Reported-by: Heiner Kallweit 
Signed-off-by: Andrew Lunn 
Signed-off-by: David S. Miller

net: phy: improve generic EEE ethtool functions

2018-12-03T23:13:25+00:00

So far the two functions consider neither member eee_enabled nor
eee_active. Therefore network drivers have to do this in some kind
of glue code. I think this can be avoided.

Getting EEE parameters:
When not advertising any EEE mode, we can't consider EEE to be enabled.
Therefore interpret "EEE enabled" as "we advertise at least one EEE
mode". It's similar with "EEE active": interpret it as "EEE modes
advertised by both link partner have at least one mode in common".

Setting EEE parameters:
If eee_enabled isn't set, don't advertise any EEE mode and restart
aneg if needed to switch off EEE. If eee_enabled is set and
data->advertised is empty (e.g. because EEE was disabled), advertise
everything we support as default. This way EEE can easily switched
on/off by doing ethtool --set-eee  eee on/off, w/o any additional
parameters.

The changes to both functions shouldn't break any existing user.
Once the changes have been applied, at least some users can be
simplified.

Signed-off-by: Heiner Kallweit 
Signed-off-by: David S. Miller

net: phy: check if advertising is zero using linkmode_empty

2018-11-13T00:26:21+00:00

A recent change modified variable advertising from a u32 to a link mode
array and left the u32 zero comparison, so essential we now have an array
being compared to null which is not the intention. Fix this by using the
call to linkmode_empty to check if advertising is all zero.

Detected by CoverityScan, CID#1475424 ("Array compared against 0")

Fixes: 3c1bcc8614db ("net: ethernet: Convert phydev advertize and supported from u32 to link mode")
Signed-off-by: Colin Ian King 
Reviewed-by: Andrew Lunn 
Signed-off-by: David S. Miller

net: phy: Convert u32 phydev->lp_advertising to linkmode

2018-11-11T18:10:01+00:00

Convert phy drivers to report the link partner advertised modes using
a linkmode bitmap. This allows them to report the higher speeds which
don't fit in a u32.

Signed-off-by: Andrew Lunn 
Signed-off-by: David S. Miller