Re: Is the ppc440 "bamboo" board in QEMU still of any use?

[Thomas Huth <thuth@redhat.com>]

On 14/10/2021 17.26, Philippe Mathieu-Daudé wrote:
> On 10/14/21 13:29, Cédric Le Goater wrote:
>> On 10/14/21 12:34, Christophe Leroy wrote:
> 
>>> I have the following change in QEMU to be able to run the bamboo,
>>> found it some time ago via google (can't remember where):
>>>
>>> diff --git a/hw/ppc/ppc4xx_pci.c b/hw/ppc/ppc4xx_pci.c
>>> index 8147ba6f94..600e89e791 100644
>>> --- a/hw/ppc/ppc4xx_pci.c
>>> +++ b/hw/ppc/ppc4xx_pci.c
>>> @@ -246,7 +246,7 @@ static int ppc4xx_pci_map_irq(PCIDevice *pci_dev,
>>> int irq_num)
>>>
>>>        trace_ppc4xx_pci_map_irq(pci_dev->devfn, irq_num, slot);
>>>
>>> -    return slot - 1;
>>> +    return slot ? slot - 1 : slot;
>>>    }
>>>
>>>    static void ppc4xx_pci_set_irq(void *opaque, int irq_num, int level)
>>
>> could you try to use :
>>
>> static inline int ppce500_pci_map_irq_slot(int devno, int irq_num)
>> {
>>      return (devno + irq_num) % 4;
>> }
> 
> Is this pci_swizzle()?

It's pci_swizzle, but I don't think that we should take irq_num into account 
here. The comment right in front of the function says:

  On Bamboo, all pins from each slot are tied to a single board IRQ

Similar comment in pc-bios/bamboo.dts:

  Bamboo has all 4 IRQ pins tied together per slot

So the return value should only depend on the slot number.

Not sure how to properly fix this yet, though.

  Thomas


PS: Found a working pre-compiled kernel for bamboo:
http://landley.net/aboriginal/downloads/binaries/system-image-powerpc-440fp.tar.gz