On 13/01/15 12:34, Yijing Wang wrote:
>> static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
>> struct pci_dev *bridge, int busnr)
>> {
>> @@ -713,6 +727,7 @@ static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
>> bridge->subordinate = child;
>>
>> add_dev:
>> + pci_set_bus_msi_domain(child);
>> ret = device_register(&child->dev);
>> WARN_ON(ret < 0);
>>
>> @@ -1507,6 +1522,17 @@ static void pci_init_capabilities(struct pci_dev *dev)
>> pci_enable_acs(dev);
>> }
>>
>> +static void pci_set_msi_domain(struct pci_dev *dev)
>> +{
>> + /*
>> + * If no domain has been set through the pcibios callback,
>> + * inherit the default from the bus device.
>> + */
>> + if (!dev_get_msi_domain(&dev->dev))
>> + dev_set_msi_domain(&dev->dev,
>> + dev_get_msi_domain(&dev->bus->dev));
>> +}
>
> Hi Marc, now we have two ways to associate the pci_dev and msi_domain, right ?
>
> 1. associate pci_dev and msi_domain in pcibios_add_device() like x86.
>
> 2. Inherit msi_domain from pci_dev->bus.
>
> My question is if all pci devices inherit msi_domain from the pci_bus,
> so all pci devices under same pci host bridge have the same msi_domain assigned by
> weak pcibios_set_phb_msi_domain(). So why not save the pci host bridge specific
> msi_domain in pci_host_bridge. Then pci devices could inherit the msi_domain from
> its pci host bridge directly, no need to involve pci bus in the assignment.
But then, you would end-up maintaining another msi_domain field inside
the pci_host bridge structure. What do you gain by doing so?
With this series, msi_domain has the nice property of always being tied
to a device (and struct pci_bus always has a device). We always have
phb->bus->dev.msi_domain within reach, and architecture code can decide
to override it on a per-device basis.
What else do you need? What am I missing from your proposal?
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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