QEMU emulates two of the three PCI buses found on real hardware because some clients seem to need both and fail with only one present, but OpenBIOS only handles a single PCI bus and initialises and puts in the device tree only one of these: the second one which is where devices are connected and also marks it bus 0. However, clients getting info from the device tree may not know about this and thinking there is only one PCI bus they erroneously use the address of the first bus to access PCI config registers for devices on the second bus which silently fails as these requests will go to the other empty bus emulated and return invalid values. Devices mapped via MMIO still appear to work but they may not be correctly initialised and some cards are not detected because of this.
Until support for multiple PCI buses is implemented add an empty node in the device tree for the uninitialised bus to let clients know about it. This is still not entirely correct as bus-range property does not match real hardware but this fixes detecting PCI devices (such as USB) under MorphOS and may also fix enabling the bus master bit needed with some network cards and allow the workaround for this to be reverted.
Signed-off-by: BALATON Zoltan balaton@eik.bme.hu --- arch/ppc/qemu/init.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+)
v2: Move to init.c from tree.fs and only add it for mac99 Patches 1 and 2 from original series https://www.coreboot.org/pipermail/openbios/2016-November/009825.html https://www.coreboot.org/pipermail/openbios/2016-November/009824.html are still valid and needed, patch 4 was already applied so only this one (3/4) is resent but 1 and 2 should be applied as well with this.
diff --git a/arch/ppc/qemu/init.c b/arch/ppc/qemu/init.c index ffbf08d..629d71b 100644 --- a/arch/ppc/qemu/init.c +++ b/arch/ppc/qemu/init.c @@ -755,6 +755,44 @@ arch_of_init(void) openbios_init(); modules_init(); setup_timers(); + if (machine_id == ARCH_MAC99) { + /* Add empty node for first pci bus */ + /* Remove this when pci driver is fixed to handle multiple buses */ + activate_device("/"); + fword("new-device"); + push_str("pci"); + fword("device-name"); + push_str("pci"); + fword("device-type"); + PUSH(0xf0000000); + fword("encode-int"); + PUSH(0x02000000); + fword("encode-int"); + fword("encode+"); + push_str("reg"); + fword("property"); + PUSH(3); + fword("encode-int"); + push_str("#address-cells"); + fword("property"); + PUSH(2); + fword("encode-int"); + push_str("#size-cells"); + fword("property"); + PUSH(1); + fword("encode-int"); + push_str("#interrupt-cells"); + fword("property"); + PUSH(0); + fword("encode-int"); + PUSH(0); + fword("encode-int"); + fword("encode+"); + push_str("bus-range"); + fword("property"); + fword("finish-device"); + device_end(); + } #ifdef CONFIG_DRIVER_PCI ob_pci_init(); #endif