Messages in this thread | | | Date | Tue, 09 Dec 2014 12:12:55 +0000 | From | Marc Zyngier <> | Subject | Re: [PATCH 2/6] PCI/MSI: add hooks to populate the msi_domain field |
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Yijing,
On 09/12/14 11:57, Yijing Wang wrote: >>>> +void __weak pcibios_set_phb_msi_domain(struct pci_bus *bus) >>>> +{ >>>> +} >>>> + >>>> +static void pci_set_bus_msi_domain(struct pci_bus *bus) >>>> +{ >>>> + struct pci_dev *bridge = bus->self; >>>> + >>>> + if (!bridge) >>>> + pcibios_set_phb_msi_domain(bus); >>>> + else >>>> + dev_set_msi_domain(&bus->dev, dev_get_msi_domain(&bridge->dev)); >>>> +} >>> >>> >>> Hi Marc, we can not assume pci devices under same phb share the same msi irq domain, >>> now in x86, pci devices under the same phb may associate different msi irq domain. > > Hi Marc, > >> >> Well, this is not supposed to be a perfect solution yet, but instead a >> basis for discussion. What I'd like to find out is: >> >> - What is the minimum granularity for associating a device with its MSI >> domain in existing platforms? > > PCI device, after Gerry's msi irq domain patchset which now in linux-next, > in x86, we will find msi irq domain by pci_dev.
Are you *really* associating the MSI domain on a per pci-device basis? That is, you have devices on the same PCI bus talking to different MSI hw?
> I generally agree your first patch which associate basic device with msi irq domain. > >> - What topology data structures do you use to find out what MSI >> controller a device should be matched with? > > Now only arm and arm64 use msi controller to setup/teardown msi irqs, > in arm, now msi controller saved in pci_sys_data, and for arm64, it seems > to be saved in pci_bus. For a more common method to find msi controller/irq domain, > I prefer pci_dev/device.
Forget about msi_controller, the whole goal of this series is to make it obsolete. On your x86 platform, what how do you identify which MSI domain should be associated with a given PCI device? Surely you must have a set of data structures or ACPI tables which give you that information.
>> - What in-tree platform already has this requirements? > > As mentioned above, x86 does.
Let me rephrase that in a non-ambiguous manner: can you point me to a file implementing this in mainline?
Thanks,
M. -- Jazz is not dead. It just smells funny...
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