Remember when I said many months ago that something with PCI was fishy? That PCI devices were in the device tree twice and init functions were called multiple times? Turns out I was right and the bug is totally nasty. I finally tracked it down after tracing function calls for 6 hours in qemu.
pci_scan_bus(bus, ...) is not called with the expected bus type. Instead, it is called with a domain type from pci_domain_scan_bus(). pci_scan_bus(bus, ...) looks at bus->children and expects it to be a PCI device. Of course the children of the domain are the buses and bus->children is a PCI bus. That causes all lookups in the device tree to fail horribly.
This patch fixes the dts lookup, BUT it introduces new undesired behaviour:
- Only the first bus of a PCI domain is scanned. That's fixable in an obvious way.
- For dynamic PCI devices on qemu, have_resources is now always 0. The reason can be seen in this error message: "read_resources: bus_0(PCI_BUS: 0000) missing phase4_read_resources" Basically, we have phase4_read_resources defined for the PCI domain, but not for PCI bus 0. We can either inherit phase4_read_resources from the domain or we define phase4_read_resources for each PCI bus. I prefer the latter.
Signed-off-by: Carl-Daniel Hailfinger c-d.hailfinger.devel.2006@gmx.net
Index: corebootv3-pci_scan_bus/device/pci_device.c =================================================================== --- corebootv3-pci_scan_bus/device/pci_device.c (Revision 842) +++ corebootv3-pci_scan_bus/device/pci_device.c (Arbeitskopie) @@ -636,6 +636,8 @@ vendor = mainboard_pci_subsystem_vendor; if (!device) device = mainboard_pci_subsystem_device; + } else { + printk(BIOS_DEBUG, "%s: Device not on_mainboard\n", dev_path(dev)); } #endif /* Set the subsystem vendor and device ID for mainboard devices. */ @@ -1098,6 +1100,10 @@
printk(BIOS_DEBUG, "%s start bus %p, bus->dev %p\n", __func__, bus, bus->dev); + if (bus->dev->path.type != DEVICE_PATH_PCI_BUS) + printk(BIOS_ERR, "ERROR: pci_scan_bus called with incorrect " + "bus->dev->path.type, path is %s\n", dev_path(bus->dev)); + #if PCI_BUS_SEGN_BITS printk(BIOS_DEBUG, "PCI: pci_scan_bus for bus %04x:%02x\n", bus->secondary >> 8, bus->secondary & 0xff); @@ -1139,6 +1145,8 @@ if ((PCI_FUNC(devfn) == 0x00) && (!dev || (dev->enabled && ((dev->hdr_type & 0x80) != 0x80)))) { + printk(BIOS_SPEW, "Not a multi function device, or the " + "device is not present. Skip to next device.\n"); devfn += 0x07; } } @@ -1186,8 +1194,9 @@ */ unsigned int pci_domain_scan_bus(struct device *dev, unsigned int max) { + printk(BIOS_SPEW, "pci_domain_scan_bus: calling pci_scan_bus\n"); /* There is only one link on this device, and it is always link 0. */ - return pci_scan_bus(&dev->link[0], PCI_DEVFN(0, 0), 0xff, max); + return pci_scan_bus(&dev->link[0].children->link[0], PCI_DEVFN(0, 0), 0xff, max); }
/** @@ -1277,6 +1286,7 @@ */ unsigned int pci_scan_bridge(struct device *dev, unsigned int max) { + printk(BIOS_SPEW, "pci_scan_bridge: calling pci_scan_bus\n"); return do_pci_scan_bridge(dev, max, pci_scan_bus); }