dm: pci: Support bridge device configuration correctly

Commit aec241d "dm: pci: Use the correct hose when configuring devices"
was an attempt to fix pci bridge device configuration, but unfortunately
that does not work 100%. In pciauto_config_devices(), the fix tried to
call pciauto_config_device() with a ctlr_hose which is supposed to be
the root controller hose, however when walking through a pci topology
with 2 or more pci bridges this logic simply fails.

The call chain is: pciauto_config_devices()->pciauto_config_device()
->dm_pci_hose_probe_bus(). Here the call to dm_pci_hose_probe_bus()
does not make any sense as the given hose is not the bridge device's
hose, instead it is either the root controller's hose (case#1: if it
is the 2nd pci bridge), or the bridge's parent bridge's hose (case#2:
if it is the 3rd pci bridge). In both cases the logic is wrong.

For example, for failing case#1 if the bridge device to config has the
same devfn as one of the devices under the root controller, the call
to pci_bus_find_devfn() will return the udevice of that pci device
under the root controller as the bus, but this is wrong as the udevice
is not a bus which does not contain all the necessary bits associated
with the udevice which causes further failures.

To correctly support pci bridge device configuration, we should still
call pciauto_config_device() with the pci bridge's hose directly.
In order to access valid pci region information, we need to refer to
the root controller simply by a call to pci_bus_to_hose(0) and get the
region information there in the pciauto_prescan_setup_bridge(),
pciauto_postscan_setup_bridge() and pciauto_config_device().

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>

1 files changed, 1 insertions, 5 deletions

diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c
index bc0be1e9e4..c7d93f92d6 100644
--- a/drivers/pci/pci-uclass.c
+++ b/drivers/pci/pci-uclass.c
@@ -301,14 +301,10 @@ int pci_auto_config_devices(struct udevice *bus)
 	for (ret = device_find_first_child(bus, &dev);
 	     !ret && dev;
 	     ret = device_find_next_child(&dev)) {
-		struct pci_controller *ctlr_hose;
 		unsigned int max_bus;
 
 		debug("%s: device %s\n", __func__, dev->name);
-
-		/* The root controller has the region information */
-		ctlr_hose = hose->ctlr->uclass_priv;
-		max_bus = pciauto_config_device(ctlr_hose, pci_get_bdf(dev));
+		max_bus = pciauto_config_device(hose, pci_get_bdf(dev));
 		sub_bus = max(sub_bus, max_bus);
 	}
 	debug("%s: done\n", __func__);