Re: [PATCH v5 09/14] ACPI: platform: setup MSI domain for ACPI based platform device

[Rafael J. Wysocki]

On Sat, Dec 24, 2016 at 8:34 AM, Hanjun Guo <guohanjun@xxxxxxxxxx> wrote:
> Hi Rafael,
>
> Thank you for your comments, when I was demoing your suggestion,
> I got a little bit confusions, please see my comments below.
>

[cut]

>>> +
>>> +/**
>>>   * acpi_create_platform_device - Create platform device for ACPI device node
>>>   * @adev: ACPI device node to create a platform device for.
>>>   * @properties: Optional collection of build-in properties.
>>> @@ -109,6 +119,7 @@ struct platform_device *acpi_create_platform_device(struct acpi_device *adev,
>>>         pdevinfo.num_res = count;
>>>         pdevinfo.fwnode = acpi_fwnode_handle(adev);
>>>         pdevinfo.properties = properties;
>>> +       pdevinfo.pre_add_cb = acpi_platform_pre_add_cb;
>> Why don't you point that directly to acpi_configure_pmsi_domain()?  It
>> doesn't look like the wrapper is necessary at all.
>
> I was thinking that we can add something more in the future
> if we need to extend the function of the callback, I can just
> use acpi_configure_pmsi_domain() here.

So you can add the wrapper in the future just fine as well.  At this
point it is just redundant.

>>
>> And I'm not sure why the new callback is necessary ->
>
> I was demoing your suggestion but...
>
>>
>>>         if (acpi_dma_supported(adev))
>>>                 pdevinfo.dma_mask = DMA_BIT_MASK(32);
>>> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
>>> index bc68d93..6b72fcb 100644
>>> --- a/drivers/acpi/arm64/iort.c
>>> +++ b/drivers/acpi/arm64/iort.c
>>> @@ -527,6 +527,49 @@ struct irq_domain *iort_get_device_domain(struct device *dev, u32 req_id)
>>>         return irq_find_matching_fwnode(handle, DOMAIN_BUS_PCI_MSI);
>>>  }
>>>
>>> +/**
>>> + * iort_get_platform_device_domain() - Find MSI domain related to a
>>> + * platform device
>>> + * @dev: the dev pointer associated with the platform device
>>> + *
>>> + * Returns: the MSI domain for this device, NULL otherwise
>>> + */
>>> +static struct irq_domain *iort_get_platform_device_domain(struct device *dev)
>>> +{
>>> +       struct acpi_iort_node *node, *msi_parent;
>>> +       struct fwnode_handle *iort_fwnode;
>>> +       struct acpi_iort_its_group *its;
>>> +
>>> +       /* find its associated iort node */
>>> +       node = iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT,
>>> +                             iort_match_node_callback, dev);
>>> +       if (!node)
>>> +               return NULL;
>>> +
>>> +       /* then find its msi parent node */
>>> +       msi_parent = iort_node_get_id(node, NULL, IORT_MSI_TYPE, 0);
>>> +       if (!msi_parent)
>>> +               return NULL;
>>> +
>>> +       /* Move to ITS specific data */
>>> +       its = (struct acpi_iort_its_group *)msi_parent->node_data;
>>> +
>>> +       iort_fwnode = iort_find_domain_token(its->identifiers[0]);
>>> +       if (!iort_fwnode)
>>> +               return NULL;
>>> +
>>> +       return irq_find_matching_fwnode(iort_fwnode, DOMAIN_BUS_PLATFORM_MSI);
>>> +}
>>> +
>>> +void acpi_configure_pmsi_domain(struct device *dev)
>>> +{
>>> +       struct irq_domain *msi_domain;
>>> +
>>> +       msi_domain = iort_get_platform_device_domain(dev);
>>> +       if (msi_domain)
>>> +               dev_set_msi_domain(dev, msi_domain);
>>> +}
>>> +
>>>  static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data)
>>>  {
>>>         u32 *rid = data;
>>> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
>>> index c4af003..3e68f31 100644
>>> --- a/drivers/base/platform.c
>>> +++ b/drivers/base/platform.c
>>> @@ -537,6 +537,9 @@ struct platform_device *platform_device_register_full(
>>>                         goto err;
>>>         }
>>>
>>> +       if (pdevinfo->pre_add_cb)
>>> +               pdevinfo->pre_add_cb(&pdev->dev);
>>> +
>> -> because it looks like this might be done in acpi_platform_notify()
>> for platform devices.
>
> It works and I just simply add the code below:
>
> diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
> index f8d6564..e0cd649 100644
> --- a/drivers/acpi/glue.c
> +++ b/drivers/acpi/glue.c
> @@ -13,6 +13,7 @@
>  #include <linux/slab.h>
>  #include <linux/rwsem.h>
>  #include <linux/acpi.h>
> +#include <linux/acpi_iort.h>
>  #include <linux/dma-mapping.h>
>
>  #include "internal.h"
> @@ -315,6 +316,8 @@ static int acpi_platform_notify(struct device *dev)
>         if (!adev)
>                 goto out;
>
> + acpi_configure_pmsi_domain(dev);
> +

But that should apply to platform devices only I suppose?

>         if (type && type->setup)
>                 type->setup(dev);
>         else if (adev->handler && adev->handler->bind)
>
> Do you suggesting to configure the msi domain in this way?
> or add the function in the type->setup() callback (which needs
> to introduce a new acpi bus type)?

A type->setup() would be somewhat cleaner I think, but then it's more
code.  Whichever works better I guess. :-)

Thanks,
Rafael