diff mbox

[V3,11/21] pci, acpi: Move ACPI host bridge device companion assignment to core code.

Message ID 569F8E38.5030101@semihalf.com (mailing list archive)
State New, archived
Delegated to: Bjorn Helgaas
Headers show

Commit Message

Tomasz Nowicki Jan. 20, 2016, 1:40 p.m. UTC
On 20.01.2016 13:38, Lorenzo Pieralisi wrote:
> On Wed, Jan 20, 2016 at 12:20:07PM +0100, Tomasz Nowicki wrote:
>> On 19.01.2016 17:02, Lorenzo Pieralisi wrote:
>>> On Wed, Jan 13, 2016 at 02:20:57PM +0100, Tomasz Nowicki wrote:
>> [...]
>>>> device via pci_create_root_bus parameter (as the ACPI device type)
>>>
>>> I do not understand what you mean by "as the ACPI device type".
>>
>> See below.
>>
>>>
>>>> and using ACPI_COMPANION_SET in core code for ACPI boot method.
>>>> ACPI_COMPANION_SET is safe to run for all cases DT, ACPI and DT&ACPI.
>>>>
>>>> Suggested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
>>>> Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
>>>> ---
>>>>   drivers/acpi/pci_root.c | 5 ++++-
>>>>   drivers/pci/probe.c     | 2 ++
>>>>   2 files changed, 6 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
>>>> index ae3fe4e..a65c8c2 100644
>>>> --- a/drivers/acpi/pci_root.c
>>>> +++ b/drivers/acpi/pci_root.c
>>>> @@ -846,7 +846,10 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
>>>>
>>>>   	pci_acpi_root_add_resources(info);
>>>>   	pci_add_resource(&info->resources, &root->secondary);
>>>> -	bus = pci_create_root_bus(NULL, busnum, ops->pci_ops,
>>>> +
>>>> +	/* Root bridge device needs to be sure of parent ACPI type */
>>>> +	ACPI_COMPANION_SET(&device->dev, device);
>>>
>>> I do not understand why the code above is needed, can you elaborate
>>> please ?
>>>
>>
>> This makes sure that device->dev can be identified as ACPI device,
>> so we can use to_acpi_device_node() and assign companion safely
>> below.
>
> I do not follow. If you refer to the fwnode handle type, that is
> already set by ACPI core code (before acpi_pci_root_add() is called,
> in acpi_init_device_object()).

acpi_init_device_object() sets ACPI fwnode handle type only for 
"device", but not for "device->dev" which is what is passed as an 
argument to pci_create_root_bus().

Without ACPI_COMPANION_SET(&device->dev, device) here, no one can be 
sure if we have ACPI device in pci_create_root_bus().

>
> Did you add the code above to solve a real issue you encountered ?
Yes. You can try to run series with this patch:


Thanks,
Tomasz
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Comments

Lorenzo Pieralisi Jan. 20, 2016, 2:22 p.m. UTC | #1
On Wed, Jan 20, 2016 at 02:40:08PM +0100, Tomasz Nowicki wrote:

[...]

> >>>>+	/* Root bridge device needs to be sure of parent ACPI type */
> >>>>+	ACPI_COMPANION_SET(&device->dev, device);
> >>>
> >>>I do not understand why the code above is needed, can you elaborate
> >>>please ?
> >>>
> >>
> >>This makes sure that device->dev can be identified as ACPI device,
> >>so we can use to_acpi_device_node() and assign companion safely
> >>below.
> >
> >I do not follow. If you refer to the fwnode handle type, that is
> >already set by ACPI core code (before acpi_pci_root_add() is called,
> >in acpi_init_device_object()).
> 
> acpi_init_device_object() sets ACPI fwnode handle type only for
> "device", but not for "device->dev" which is what is passed as an
> argument to pci_create_root_bus().
> 
> Without ACPI_COMPANION_SET(&device->dev, device) here, no one can be
> sure if we have ACPI device in pci_create_root_bus().

Ok, got it. The question is whether this should be done in ACPI
core instead (is there a reason why it should *not* be done ?), but I
now understand your point.

Thanks,
Lorenzo
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Tomasz Nowicki Jan. 20, 2016, 2:41 p.m. UTC | #2
On 20.01.2016 15:22, Lorenzo Pieralisi wrote:
> On Wed, Jan 20, 2016 at 02:40:08PM +0100, Tomasz Nowicki wrote:
>
> [...]
>
>>>>>> +	/* Root bridge device needs to be sure of parent ACPI type */
>>>>>> +	ACPI_COMPANION_SET(&device->dev, device);
>>>>>
>>>>> I do not understand why the code above is needed, can you elaborate
>>>>> please ?
>>>>>
>>>>
>>>> This makes sure that device->dev can be identified as ACPI device,
>>>> so we can use to_acpi_device_node() and assign companion safely
>>>> below.
>>>
>>> I do not follow. If you refer to the fwnode handle type, that is
>>> already set by ACPI core code (before acpi_pci_root_add() is called,
>>> in acpi_init_device_object()).
>>
>> acpi_init_device_object() sets ACPI fwnode handle type only for
>> "device", but not for "device->dev" which is what is passed as an
>> argument to pci_create_root_bus().
>>
>> Without ACPI_COMPANION_SET(&device->dev, device) here, no one can be
>> sure if we have ACPI device in pci_create_root_bus().
>
> Ok, got it. The question is whether this should be done in ACPI
> core instead (is there a reason why it should *not* be done ?), but I
> now understand your point.
>

I am not able to answer that question, but I see lots of changes in this 
area made by Rafael.

Rafael, can you please shed some light on this?

Thanks,
Tomasz
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Lorenzo Pieralisi Jan. 27, 2016, 5:42 p.m. UTC | #3
On Wed, Jan 20, 2016 at 03:41:56PM +0100, Tomasz Nowicki wrote:
> On 20.01.2016 15:22, Lorenzo Pieralisi wrote:
> >On Wed, Jan 20, 2016 at 02:40:08PM +0100, Tomasz Nowicki wrote:
> >
> >[...]
> >
> >>>>>>+	/* Root bridge device needs to be sure of parent ACPI type */
> >>>>>>+	ACPI_COMPANION_SET(&device->dev, device);
> >>>>>
> >>>>>I do not understand why the code above is needed, can you elaborate
> >>>>>please ?
> >>>>>
> >>>>
> >>>>This makes sure that device->dev can be identified as ACPI device,
> >>>>so we can use to_acpi_device_node() and assign companion safely
> >>>>below.
> >>>
> >>>I do not follow. If you refer to the fwnode handle type, that is
> >>>already set by ACPI core code (before acpi_pci_root_add() is called,
> >>>in acpi_init_device_object()).
> >>
> >>acpi_init_device_object() sets ACPI fwnode handle type only for
> >>"device", but not for "device->dev" which is what is passed as an
> >>argument to pci_create_root_bus().
> >>
> >>Without ACPI_COMPANION_SET(&device->dev, device) here, no one can be
> >>sure if we have ACPI device in pci_create_root_bus().
> >
> >Ok, got it. The question is whether this should be done in ACPI
> >core instead (is there a reason why it should *not* be done ?), but I
> >now understand your point.
> >
> 
> I am not able to answer that question, but I see lots of changes in
> this area made by Rafael.

I had a further look and I am not sure why the fwnode_handle* in the
dev member of the acpi_device is not made to point at the fwnode member
of the acpi_device by *default* (acpi_init_device_object() ?), probably
because it is never used as such but certainly Rafael knows, so I would
ask him to clarify please it is unclear to me.

I do not see anything wrong in what you are doing in this patch.

Rafael, any comments ?

Thanks,
Lorenzo
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diff mbox

Patch

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 88c9d20..1b74bf6 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -967,7 +967,11 @@  struct pci_bus *acpi_pci_root_create(struct 
acpi_pci_root *root,
         pci_add_resource(&info->resources, &root->secondary);

-        /* Root bridge device needs to be sure of parent ACPI type */
-       ACPI_COMPANION_SET(&device->dev, device);
+       if (to_acpi_device_node(device->dev.fwnode) == NULL)
+               pr_err("NON-ACPI TYPE\n");
+       else
+               pr_err("ACPI TYPE\n");
+
         bus = pci_create_root_bus(&device->dev, busnum, ops->pci_ops,
                                   sysdata, &info->resources);