Messages in this thread Patch in this message | | | From | Vladimir Oltean <> | Date | Fri, 13 Mar 2020 00:07:37 +0200 | Subject | Re: [PATCH 1/2] net: dsa: felix: allow the device to be disabled |
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On Thu, 12 Mar 2020 at 23:45, Florian Fainelli <f.fainelli@gmail.com> wrote: > > On 3/12/20 2:35 PM, Vladimir Oltean wrote: > > On Thu, 12 Mar 2020 at 18:44, Michael Walle <michael@walle.cc> wrote: > >> > >> If there is no specific configuration of the felix switch in the device > >> tree, but only the default configuration (ie. given by the SoCs dtsi > >> file), the probe fails because no CPU port has been set. On the other > >> hand you cannot set a default CPU port because that depends on the > >> actual board using the switch. > >> > >> [ 2.701300] DSA: tree 0 has no CPU port > >> [ 2.705167] mscc_felix 0000:00:00.5: Failed to register DSA switch: -22 > >> [ 2.711844] mscc_felix: probe of 0000:00:00.5 failed with error -22 > >> > >> Thus let the device tree disable this device entirely, like it is also > >> done with the enetc driver of the same SoC. > >> > >> Signed-off-by: Michael Walle <michael@walle.cc> > >> --- > >> drivers/net/dsa/ocelot/felix.c | 5 +++++ > >> 1 file changed, 5 insertions(+) > >> > >> diff --git a/drivers/net/dsa/ocelot/felix.c b/drivers/net/dsa/ocelot/felix.c > >> index 69546383a382..531c7710063f 100644 > >> --- a/drivers/net/dsa/ocelot/felix.c > >> +++ b/drivers/net/dsa/ocelot/felix.c > >> @@ -699,6 +699,11 @@ static int felix_pci_probe(struct pci_dev *pdev, > >> struct felix *felix; > >> int err; > >> > >> + if (pdev->dev.of_node && !of_device_is_available(pdev->dev.of_node)) { > >> + dev_info(&pdev->dev, "device is disabled, skipping\n"); > >> + return -ENODEV; > >> + } > >> + > > > > IMHO since DSA is already dependent on device tree for PHY bindings, > > it would make more sense to move this there: > > Michael's solution makes more sense, as this is a driver specific > problem whereby you have a pci_dev instance that is created and does not > honor the status property provided in Device Tree. If you were to look > for a proper solution it would likely be within the PCI core actually. > > No other DSA switch has that problem because they use the > I2C/SPI/platform_device/GPIO/whatever entry points into the driver model.
True, my problem with doing it in the PCI core is that "the book" [0] doesn't actually say anything about the "status" property, so this patch might get some pushback from the PCI maintainers (but I don't actually know):
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 512cb4312ddd..50c2b3da134a 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -2281,6 +2281,12 @@ static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn)
pci_set_of_node(dev);
+ if (dev->dev.of_node && !of_device_is_available(dev->dev.of_node)) { + pci_bus_put(dev->bus); + kfree(dev); + return NULL; + } + if (pci_setup_device(dev)) { pci_bus_put(dev->bus); kfree(dev); OF bindings are completely optional with PCI, as you probably already know. But there's nothing "driver" specific in disabling (i.e. not probing) a device.
> -- >
[0] https://www.openfirmware.info/data/docs/bus.pci.pdf
Thanks, -Vladimir
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