PCI: Don't allow unbinding host controllers that aren't prepared
Many PCI host controller drivers aren't prepared to have their devices
unbound from them forcefully (e.g., through /sys/.../<driver>/unbind), as
they don't provide any driver .remove callback, where they'd detach the
root bus, release resources, etc. Keeping the driver built in (i.e., not a
loadable module) is not enough; and providing no .remove callback just
means we don't do any teardown.
To rule out the possibility of unbinding a device via sysfs, we need to set
the ".suppress_bind_attrs" field.
I found the suspect drivers via the following search:
git grep -l platform_driver $(git grep -L -e '\.remove' -e suppress_bind_attrs drivers/pci/)
Then I inspected them to ensure that
(a) they set up a PCI bus in their probe() and
(b) they don't have a remove() callback for undoing the setup
Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/drivers/pci/dwc/pci-imx6.c b/drivers/pci/dwc/pci-imx6.c
index 129717a..a98cba5 100644
--- a/drivers/pci/dwc/pci-imx6.c
+++ b/drivers/pci/dwc/pci-imx6.c
@@ -804,6 +804,7 @@ static struct platform_driver imx6_pcie_driver = {
.driver = {
.name = "imx6q-pcie",
.of_match_table = imx6_pcie_of_match,
+ .suppress_bind_attrs = true,
},
.probe = imx6_pcie_probe,
.shutdown = imx6_pcie_shutdown,