Subject: Re: [PATCH 2/2] powerpc/powernc: revert part of commit d905c5df(PPC: POWERNV: move iommu_add_device earlier)

From: Wei Yang <[email-masked]>
Date: Mon, 21 Apr 2014 14:11:37 +0800

On Mon, Apr 21, 2014 at 01:22:13PM +0800, Wei Yang wrote:
>On Mon, Apr 21, 2014 at 01:37:32PM +1000, Benjamin Herrenschmidt wrote:
>>On Mon, 2014-04-21 at 10:25 +0800, Wei Yang wrote:
>>> Here is a draft call flow:
>>> 
>>> pci_device_add
>>>    pcibios_add_device
>>>       pci_dma_dev_setup
>>>          pnv_pci_dma_dev_setup
>>>             pnv_pci_ioda_dma_dev_setup
>>>                set_iommu_table_base_and_group <--- here
>>> device_add
>>> 
>>> When set_iommu_table_base_and_group() is invoked int
>>> pnv_pci_ioda_dma_dev_setup(), the dev->kobj->sd is not initialized. The
>>> dev->kobj->sd is initialized in device_add().
>>> 
>>> After applying this patch, the error
>>>     iommu_tce: 0003:05:00.0 has not been added, ret=-14
>>> is cleared.
>>> 
>>> This patch revert the change for pnv_pci_ioda_dma_dev_setup() from commit
>>> d905c5df(PPC: POWERNV: move iommu_add_device earlier).
>>
>>But in that case, is the group still set ?
>
>I think so.
>
>iommu_add_device() will be invoked when device_add() notify the pci bus.
>

Did a quick test, after applying this patch, the logic would be the same for
VF and PF hotplug, the iommu_group is created with corresponding device.