[PATCH] iommu/arm-smmu-v2: Add support for 16 bit VMID

[Tirumalesh Chalamarla]

On 02/19/2016 09:13 AM, Will Deacon wrote:
> On Thu, Feb 18, 2016 at 10:23:37AM -0800, tchalamarla at caviumnetworks.com wrote:
>> From: Tirumalesh Chalamarla <tchalamarla at caviumnetworks.com>
>>
>> ARM-SMMUv2 supports upto 16 bit VMID. This patch enables
>> 16 bit VMID when requested from device-tree.
>>
>> Signed-off-by: Tirumalesh Chalamarla <tchalamarla at caviumnetworks.com>
>> ---
>>   .../devicetree/bindings/iommu/arm,smmu.txt          |  2 ++
>>   drivers/iommu/arm-smmu.c                            | 21 ++++++++++++++++++++-
>>   2 files changed, 22 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.txt b/Documentation/devicetree/bindings/iommu/arm,smmu.txt
>> index 7180745..bb7e569 100644
>> --- a/Documentation/devicetree/bindings/iommu/arm,smmu.txt
>> +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.txt
>> @@ -55,6 +55,8 @@ conditions.
>>                     aliases of secure registers have to be used during
>>                     SMMU configuration.
>>
>> +- smmu-enable-vmid16 : Enable 16 bit VMID, if allowed.
>
> Why do we need a new property for this, given that we can detect it
> from the ID registers? I can't think of a reason why we wouldn't use
> 16-bit VMIDs if they were available to us.
Done.
>
> Will
>