[PATCH v7 00/22] Generic DT bindings for PCI IOMMUs and ARM SMMU

[Auger Eric]

Hi,
On 14/09/2016 12:35, Robin Murphy wrote:
> On 14/09/16 09:41, Auger Eric wrote:
>> Hi,
>>
>> On 12/09/2016 18:13, Robin Murphy wrote:
>>> Hi all,
>>>
>>> To any more confusing fixups and crazily numbered extra patches, here's
>>> a quick v7 with everything rebased into the right order. The significant
>>> change this time is to implement iommu_fwspec properly from the start,
>>> which ends up being far simpler and more robust than faffing about
>>> introducing it somewhere 'less intrusive' to move toward core code later.
>>>
>>> New branch in the logical place:
>>>
>>> git://linux-arm.org/linux-rm iommu/generic-v7
>>
>> For information, as discussed privately with Robin I experience some
>> regressions with the former and now deprecated dt description.
>>
>> on my AMD Overdrive board and my old dt description I now only see a
>> single group:
>>
>> /sys/kernel/iommu_groups/
>> /sys/kernel/iommu_groups/0
>> /sys/kernel/iommu_groups/0/devices
>> /sys/kernel/iommu_groups/0/devices/e0700000.xgmac
>>
>> whereas I formerly see
>>
>> /sys/kernel/iommu_groups/
>> /sys/kernel/iommu_groups/3
>> /sys/kernel/iommu_groups/3/devices
>> /sys/kernel/iommu_groups/3/devices/0000:00:00.0
>> /sys/kernel/iommu_groups/1
>> /sys/kernel/iommu_groups/1/devices
>> /sys/kernel/iommu_groups/1/devices/e0700000.xgmac
>> /sys/kernel/iommu_groups/4
>> /sys/kernel/iommu_groups/4/devices
>> /sys/kernel/iommu_groups/4/devices/0000:00:02.2
>> /sys/kernel/iommu_groups/4/devices/0000:01:00.1
>> /sys/kernel/iommu_groups/4/devices/0000:00:02.0
>> /sys/kernel/iommu_groups/4/devices/0000:01:00.0
>> /sys/kernel/iommu_groups/2
>> /sys/kernel/iommu_groups/2/devices
>> /sys/kernel/iommu_groups/2/devices/e0900000.xgmac
>> /sys/kernel/iommu_groups/0
>> /sys/kernel/iommu_groups/0/devices
>> /sys/kernel/iommu_groups/0/devices/f0000000.pcie
>>
>> This is the group topology without ACS override. Applying the non
>> upstreamed "pci: Enable overrides for missing ACS capabilities" I used
>> to see separate groups for each PCIe components. Now I don't see any
>> difference with and without ACS override.
> 
> OK, having reproduced on my Juno, the problem looks to be that
> of_for_each_phandle() leaves err set to -ENOENT after successfully
> walking a phandle list, which makes __find_legacy_master_phandle()
> always bail out after the first SMMU.
> 
> Can you confirm that the following diff fixes things for you?

Well it improves but there are still differences in the group topology.
The PFs now are in group 0.

root at trusty:~# lspci -nk
00:00.0 0600: 1022:1a00
        Subsystem: 1022:1a00
00:02.0 0600: 1022:1a01
00:02.2 0604: 1022:1a02
        Kernel driver in use: pcieport
01:00.0 0200: 8086:1521 (rev 01)
        Subsystem: 8086:0002
        Kernel driver in use: igb
01:00.1 0200: 8086:1521 (rev 01)
        Subsystem: 8086:0002
        Kernel driver in use: igb


with your series + fix:
/sys/kernel/iommu_groups/
/sys/kernel/iommu_groups/3
/sys/kernel/iommu_groups/3/devices
/sys/kernel/iommu_groups/3/devices/0000:00:00.0
/sys/kernel/iommu_groups/1
/sys/kernel/iommu_groups/1/devices
/sys/kernel/iommu_groups/1/devices/e0700000.xgmac
/sys/kernel/iommu_groups/4
/sys/kernel/iommu_groups/4/devices
/sys/kernel/iommu_groups/4/devices/0000:00:02.2
/sys/kernel/iommu_groups/4/devices/0000:00:02.0
/sys/kernel/iommu_groups/2
/sys/kernel/iommu_groups/2/devices
/sys/kernel/iommu_groups/2/devices/e0900000.xgmac
/sys/kernel/iommu_groups/0
/sys/kernel/iommu_groups/0/devices
/sys/kernel/iommu_groups/0/devices/0000:01:00.1
/sys/kernel/iommu_groups/0/devices/f0000000.pcie
/sys/kernel/iommu_groups/0/devices/0000:01:00.0

Before (4.8-rc5):

/sys/kernel/iommu_groups/
/sys/kernel/iommu_groups/3
/sys/kernel/iommu_groups/3/devices
/sys/kernel/iommu_groups/3/devices/0000:00:00.0
/sys/kernel/iommu_groups/1
/sys/kernel/iommu_groups/1/devices
/sys/kernel/iommu_groups/1/devices/e0700000.xgmac
/sys/kernel/iommu_groups/4
/sys/kernel/iommu_groups/4/devices
/sys/kernel/iommu_groups/4/devices/0000:00:02.2
/sys/kernel/iommu_groups/4/devices/0000:01:00.1
/sys/kernel/iommu_groups/4/devices/0000:00:02.0
/sys/kernel/iommu_groups/4/devices/0000:01:00.0
/sys/kernel/iommu_groups/2
/sys/kernel/iommu_groups/2/devices
/sys/kernel/iommu_groups/2/devices/e0900000.xgmac
/sys/kernel/iommu_groups/0
/sys/kernel/iommu_groups/0/devices
/sys/kernel/iommu_groups/0/devices/f0000000.pcie

Thanks

Eric

> 
> Robin
> 
> --->8---
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index fa892d25004d..ac4aab97c93a 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -477,7 +477,7 @@ static int __find_legacy_master_phandle(struct
> device *dev, void *data)
>  			return 1;
>  		}
>  	it->node = np;
> -	return err;
> +	return err == -ENOENT ? 0 : err;
>  }
> 
>  static struct platform_driver arm_smmu_driver;
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>