Hi Stuart,
On 15/01/15 20:35, Stuart Yoder wrote:
> On Thu, Jan 8, 2015 at 11:06 AM, Marc Zyngier <marc.zyngier@xxxxxxx> 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@xxxxxxx>
>> ---
>> 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.
The question is: can we define a generic msi_desc? If yes, then your
first proposal make sense. If not, then it is the second one.
My hunch is that we'll have to move to a model that would look like this:
struct mybus_msi_desc {
struct msi_desc desc;
struct mybus_stuff stuff;
};
and move the PCI-specific stuff out of msi_desc.
Thoughts?
M.
--
Jazz is not dead. It just smells funny...
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