On 2/11/19 10:01 AM, Florian Fainelli wrote:
> On 2/11/19 9:51 AM, Rodolfo Giometti wrote:
>> On 11/02/2019 18:28, Florian Fainelli wrote:
>>> On 2/10/19 3:45 AM, Rodolfo Giometti wrote:
>>>> On 09/02/2019 20:34, Andrew Lunn wrote:
>>>>>> So we I see two possible solutions:
>>>>>>
>>>>>> 1) having both ds->slave_mii_bus and ds->ops->phy_read already
>>>>>> defined is an
>>>>>> error, then it must be signaled to the calling code, or
>>>>>
>>>>> I don't think we can do that. mv88e6xxx optionally instantiates the
>>>>> MDIO busses, depending on what is in device tree. If there is no mdio
>>>>> property, we need the DSA core to create an MDIO bus.
>>>>
>>>> OK, but using the following check to know if DSA did such allocation is
>>>> not correct because DSA drivers can allocate it by their own:
>>>>
>>>> static void dsa_switch_teardown(struct dsa_switch *ds)
>>>> {
>>>> if (ds->slave_mii_bus && ds->ops->phy_read)
>>>> mdiobus_unregister(ds->slave_mii_bus);
>>>>
>>>> Maybe can we add a flag to register ds->slave_mii_bus allocation by DSA?
>>>
>>> If drivers allocate the slave_mii_bus, or use it as a pointer to their
>>> bus, then they should not be providing a ds->ops->phy_read() callback
>>> since we assume they would have mii_bus::read and mii_bus::write set to
>>> their driver internal version.
>>
>> I see, so having ds->slave_mii_bus and ds->ops->phy_read both not NULL
>> into dsa_switch_setup() is a potential bug, I suppose... If so why not
>> adding a BUG_ON() call to signal it instead of doing nothing? :-o
>
> If you have both non NULL, then your driver did allocate
> ds->slave_mii_bus on its own, and also assigned a valid
> ds->ops->phy_read() then things will work, except that
> ds->ops->phy_read() will not be used. And yes, that is going to be
> blowing away when the whole DSA tree gets teardowned.
>
> If you want to add a check for that condition, that would be a good
> thing, just not a BUG_ON(), propagate an error back to the caller and
> abort the tree/switch probing.
Does that work:
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index a1917025e155..54cf6a5c865d 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -368,6 +368,9 @@ static int dsa_switch_setup(struct dsa_switch *ds)
if (err)
return err;
+ if (ds->slave_mii_bus && (ds->ops->phy_read || ds->ops->phy_write))
+ return -EINVAL;
+
if (!ds->slave_mii_bus && ds->ops->phy_read) {
ds->slave_mii_bus = devm_mdiobus_alloc(ds->dev);
if (!ds->slave_mii_bus)
diff --git a/net/dsa/legacy.c b/net/dsa/legacy.c
index cb42939db776..0796c6213be6 100644
--- a/net/dsa/legacy.c
+++ b/net/dsa/legacy.c
@@ -176,6 +176,9 @@ static int dsa_switch_setup_one(struct dsa_switch *ds,
if (ret)
return ret;
+ if (ds->slave_mii_bus && (ops->phy_read || ops->phy_write))
+ return -EINVAL;
+
if (!ds->slave_mii_bus && ops->phy_read) {
ds->slave_mii_bus = devm_mdiobus_alloc(ds->dev);
if (!ds->slave_mii_bus)
>
--
Florian
