Re: [PATCH v2 1/8] device core: Introduce per-device MSI domain pointer

[Stuart Yoder <b08248@gmail.com>]

Gerry,

So which direction did you take in your patch set--  a) common,
generic msi_desc, or b)  bus-specific msi_desc like Marc showed
(mybus_msi_desc)?

Thanks,
Stuart

On Sun, Jan 18, 2015 at 8:10 PM, Jiang Liu <jiang.liu@linux.intel.com> wrote:
>
>
> On 2015/1/16 4:35, Stuart Yoder wrote:
>> On Thu, Jan 8, 2015 at 11:06 AM, Marc Zyngier <marc.zyngier@arm.com> wrote:
>>> As MSI-type features are creeping into non-PCI devices, it is
>>> starting to make sense to give our struct device some form of
>>> support for this, by allowing a pointer to an MSI irq domain to
>>> be set/retrieved.
>>>
>>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>>> ---
>>>  include/linux/device.h | 20 ++++++++++++++++++++
>>>  1 file changed, 20 insertions(+)
>>>
>>> diff --git a/include/linux/device.h b/include/linux/device.h
>>> index fb50673..ec4cee5 100644
>>> --- a/include/linux/device.h
>>> +++ b/include/linux/device.h
>>> @@ -690,6 +690,7 @@ struct acpi_dev_node {
>>>   *             along with subsystem-level and driver-level callbacks.
>>>   * @pins:      For device pin management.
>>>   *             See Documentation/pinctrl.txt for details.
>>> + * @msi_domain: The generic MSI domain this device is using.
>>>   * @numa_node: NUMA node this device is close to.
>>>   * @dma_mask:  Dma mask (if dma'ble device).
>>>   * @coherent_dma_mask: Like dma_mask, but for alloc_coherent mapping as not all
>>> @@ -750,6 +751,9 @@ struct device {
>>>         struct dev_pm_info      power;
>>>         struct dev_pm_domain    *pm_domain;
>>>
>>> +#ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
>>> +       struct irq_domain       *msi_domain; /* MSI domain device uses */
>>> +#endif
>>
>> This is not a comment on this patch specifically, but a question about other
>> MSI specific fields that might be needed in struct device.
>>
>> Currently the generic MSI domain handling has hardcoded assumptions
>> that devices are PCI-- see the for_each_msi_entry() iterator in msi.h:
>>
>>   #define dev_to_msi_list(dev)            (&to_pci_dev((dev))->msi_list)
>>
>>   #define for_each_msi_entry(desc, dev)   \
>>         list_for_each_entry((desc), dev_to_msi_list((dev)), list)
>>
>> One approach would be to move the msi_list out of pci_dev and put
>> it in struct device, so all devices can have an msi_list.
>>
>> The other approach would be to keep msi_list in a bus specific
>> device struct, and then dev_to_msi_list() would need to be
>> implemented as a bus specific callback of some kind.
>>
>> The above hardcoded PCI assumption isn't going to work.   Wanted to
>> see if there is any advice in which direction to go.
> Hi Stuart,
>         I already have some a patch set to go that direction waiting
> send out for review:)
> Thanks!
> Gerry
>
>>
>> Thanks,
>> Stuart Yoder
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