diff options
author | Vladimir Oltean <vladimir.oltean@nxp.com> | 2023-03-15 19:38:43 +0300 |
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committer | Jakub Kicinski <kuba@kernel.org> | 2023-03-18 08:31:42 +0300 |
commit | b1a2de9ccfe63b50e493ebb57b85beb5785200c7 (patch) | |
tree | 5d06bc0e80eb92a38a7758f14acb1d3c4dd77604 /drivers/net/dsa/mv88e6xxx/global2.c | |
parent | 4dd2744fae6dc705c5d2298fe0f0812d34f5b64e (diff) | |
download | linux-b1a2de9ccfe63b50e493ebb57b85beb5785200c7.tar.xz |
net: dsa: mv88e6xxx: don't dispose of Global2 IRQ mappings from mdiobus code
irq_find_mapping() does not need irq_dispose_mapping(), only
irq_create_mapping() does.
Calling irq_dispose_mapping() from mv88e6xxx_g2_irq_mdio_free() and from
the error path of mv88e6xxx_g2_irq_mdio_setup() effectively means that
the mdiobus logic (for internal PHY interrupts) is disposing of a
hwirq->virq mapping which it is not responsible of (but instead, the
function pair mv88e6xxx_g2_irq_setup() + mv88e6xxx_g2_irq_free() is).
With the current code structure, this isn't such a huge problem, because
mv88e6xxx_g2_irq_mdio_free() is called relatively close to the real
owner of the IRQ mappings:
mv88e6xxx_remove()
-> mv88e6xxx_unregister_switch()
-> mv88e6xxx_mdios_unregister()
-> mv88e6xxx_g2_irq_mdio_free()
-> mv88e6xxx_g2_irq_free()
and the switch isn't 'live' in any way such that it would be able of
generating interrupts at this point (mv88e6xxx_unregister_switch() has
been called).
However, there is a desire to split mv88e6xxx_mdios_unregister() and
mv88e6xxx_g2_irq_free() such that mv88e6xxx_mdios_unregister() only gets
called from mv88e6xxx_teardown(). This is much more problematic, as can
be seen below.
In a cross-chip scenario (say 3 switches d0032004.mdio-mii:10,
d0032004.mdio-mii:11 and d0032004.mdio-mii:12 which form a single DSA
tree), it is possible to unbind the device driver from a single switch
(say d0032004.mdio-mii:10).
When that happens, mv88e6xxx_remove() will be called for just that one
switch, and this will call mv88e6xxx_unregister_switch() which will tear
down the entire tree (calling mv88e6xxx_teardown() for all 3 switches).
Assuming mv88e6xxx_mdios_unregister() was moved to mv88e6xxx_teardown(),
at this stage, all 3 switches will have called irq_dispose_mapping() on
their mdiobus virqs.
When we bind again the device driver to d0032004.mdio-mii:10,
mv88e6xxx_probe() is called for it, which calls dsa_register_switch().
The DSA tree is now complete again, and mv88e6xxx_setup() is called for
all 3 switches.
Also assuming that mv88e6xxx_mdios_register() is moved to
mv88e6xxx_setup() (the 2 assumptions go together), at this point,
d0032004.mdio-mii:11 and d0032004.mdio-mii:12 don't have an IRQ mapping
for the internal PHYs anymore, as they've disposed of it in
mv88e6xxx_teardown(). Whereas switch d0032004.mdio-mii:10 has re-created
it, because its code path comes from mv88e6xxx_probe().
Simply put, this change prepares the driver to handle the movement of
mv88e6xxx_mdios_register() to mv88e6xxx_setup() for cross-chip DSA trees.
Also, the code being deleted was partially wrong anyway (in a way which
may have hidden this other issue). mv88e6xxx_g2_irq_mdio_setup()
populates bus->irq[] starting with offset chip->info->phy_base_addr, but
the teardown path doesn't apply that offset too. So it disposes of virq
0 for phy = [ 0, phy_base_addr ).
All switch families have phy_base_addr = 0, except for MV88E6141 and
MV88E6341 which have it as 0x10. I guess those families would have
happened to work by mistake in cross-chip scenarios too.
I'm deleting the body of mv88e6xxx_g2_irq_mdio_free() but leaving its
call sites and prototype in place. This is because, if we ever need to
add back some teardown procedure in the future, it will be perhaps
error-prone to deduce the proper call sites again. Whereas like this,
no extra code should get generated, it shouldn't bother anybody.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Klaus Kudielka <klaus.kudielka@gmail.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers/net/dsa/mv88e6xxx/global2.c')
-rw-r--r-- | drivers/net/dsa/mv88e6xxx/global2.c | 20 |
1 files changed, 4 insertions, 16 deletions
diff --git a/drivers/net/dsa/mv88e6xxx/global2.c b/drivers/net/dsa/mv88e6xxx/global2.c index ed3b2f88e783..a26546d3d7b5 100644 --- a/drivers/net/dsa/mv88e6xxx/global2.c +++ b/drivers/net/dsa/mv88e6xxx/global2.c @@ -1176,31 +1176,19 @@ out: int mv88e6xxx_g2_irq_mdio_setup(struct mv88e6xxx_chip *chip, struct mii_bus *bus) { - int phy, irq, err, err_phy; + int phy, irq; for (phy = 0; phy < chip->info->num_internal_phys; phy++) { irq = irq_find_mapping(chip->g2_irq.domain, phy); - if (irq < 0) { - err = irq; - goto out; - } + if (irq < 0) + return irq; + bus->irq[chip->info->phy_base_addr + phy] = irq; } return 0; -out: - err_phy = phy; - - for (phy = 0; phy < err_phy; phy++) - irq_dispose_mapping(bus->irq[phy]); - - return err; } void mv88e6xxx_g2_irq_mdio_free(struct mv88e6xxx_chip *chip, struct mii_bus *bus) { - int phy; - - for (phy = 0; phy < chip->info->num_internal_phys; phy++) - irq_dispose_mapping(bus->irq[phy]); } |