On Fri, Feb 2, 2024 at 4:53 AM Bjorn Andersson <andersson@xxxxxxxxxx> wrote:
>
[snip]
> > +
> > +static int pci_pwrctl_notify(struct notifier_block *nb, unsigned long action,
> > + void *data)
> > +{
> > + struct pci_pwrctl *pwrctl = container_of(nb, struct pci_pwrctl, nb);
> > + struct device *dev = data;
> > +
> > + if (dev_fwnode(dev) != dev_fwnode(pwrctl->dev))
> > + return NOTIFY_DONE;
> > +
> > + switch (action) {
> > + case BUS_NOTIFY_ADD_DEVICE:
> > + device_set_of_node_from_dev(dev, pwrctl->dev);
>
> What happens if the bootloader left the power on, and the
> of_platform_populate() got probe deferred because the pwrseq wasn't
> ready, so this happens after pci_set_of_node() has been called?
>
> (I think dev->of_node will be put, then get and then node_reused
> assigned...but I'm not entirely sure)
That's exactly what will happen and the end result will be the same.
>
> > + break;
> > + case BUS_NOTIFY_BOUND_DRIVER:
> > + pwrctl->link = device_link_add(dev, pwrctl->dev,
> > + DL_FLAG_AUTOREMOVE_CONSUMER);
> > + if (!pwrctl->link)
> > + dev_err(pwrctl->dev, "Failed to add device link\n");
> > + break;
> > + case BUS_NOTIFY_UNBOUND_DRIVER:
> > + device_link_del(pwrctl->link);
>
> This might however become a NULL-pointer dereference, if dev was bound
> to its driver before the pci_pwrctl_notify() was registered for the
> pwrctl and then the PCI device is unbound.
>
> This would also happen if device_link_add() failed when the PCI device
> was bound...
>
Yes, I'll address it.
> > + break;
> > + }
> > +
> > + return NOTIFY_DONE;
> > +}
> > +
> > +int pci_pwrctl_device_enable(struct pci_pwrctl *pwrctl)
>
> This function doesn't really "enable the device", looking at the example
> driver it's rather "device_enabled" than "device_enable"...
>
I was also thinking about pci_pwrctl_device_ready() or
pci_pwrctl_device_prepared().
Bart
[snip!]
