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

From: [email-masked] (Jiang Liu)
Date: Wed, 21 Jan 2015 09:34:27 +0800

On 2015/1/21 1:17, Stuart Yoder wrote:
> 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)?
Hi Stuart,
	Currently I'm trying to go the former way as below.
Regards,
Gerry
-----------------------------------------------------------------------
struct msi_desc {
        struct list_head                list;
        unsigned int                    irq;
        unsigned int                    nvec_used;      /* number of
messages */
        struct device *                 dev;
        struct msi_msg                  msg;            /* Last set MSI
message */

#ifdef CONFIG_PCI_MSI
        union {
                struct {                                /* For PCI
MSI/MSI-X */
                        u32 masked;                     /* mask bits */
                        struct {
                                __u8    is_msix : 1;
                                __u8    multiple: 3;    /* log2 num of
messages allocated */
                                __u8    multi_cap : 3;  /* log2 num of
messages supported */
                                __u8    maskbit : 1;    /* mask-pending
bit supported ? */
                                __u8    is_64   : 1;    /* Address size:
0=32bit 1=64bit */
                                __u16   entry_nr;       /* specific
enabled entry */
                                unsigned default_irq;   /* default
pre-assigned irq */
                        } msi_attrib;
                        union {
                                u8      mask_pos;
                                void __iomem *mask_base;
                        };
                };
        };
#endif /* CONFIG_PCI_MSI */
};

> 
> Thanks,
> Stuart
> 
> On Sun, Jan 18, 2015 at 8:10 PM, Jiang Liu <[email-masked]> wrote:
>>
>>
>> On 2015/1/16 4:35, Stuart Yoder wrote:
>>> On Thu, Jan 8, 2015 at 11:06 AM, Marc Zyngier <[email-masked]> 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 <[email-masked]>
>>>> ---
>>>>  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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