Re: [PATCH 3/3] iommu/ipmmu-vmsa: Hook up r8a7796 DT matching code

[Magnus Damm]

Hi Laurent,

On Wed, Jun 8, 2016 at 9:18 AM, Laurent Pinchart
<laurent.pinchart@xxxxxxxxxxxxxxxx> wrote:
> Hi Magnus,
>
> Thank you for the patch.
>
> On Tuesday 07 Jun 2016 12:39:45 Magnus Damm wrote:
>> From: Magnus Damm <damm+renesas@xxxxxxxxxxxxx>
>>
>> Support the r8a7796 IPMMU by sharing feature flags between
>> r8a7795 and r8a7796. Also update IOMMU_OF_DECLARE to hook
>> up the updated compat string.
>>
>> Signed-off-by: Magnus Damm <damm+renesas@xxxxxxxxxxxxx>
>> ---
>>
>>  drivers/iommu/ipmmu-vmsa.c |    9 +++++++--
>>  1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> --- 0031/drivers/iommu/ipmmu-vmsa.c
>> +++ work/drivers/iommu/ipmmu-vmsa.c   2016-06-06 11:19:40.210607110 +0900
>> @@ -1074,7 +1074,7 @@ static const struct ipmmu_features ipmmu
>>       .twobit_imttbcr_sl0 = false,
>>  };
>>
>> -static const struct ipmmu_features ipmmu_features_r8a7795 = {
>> +static const struct ipmmu_features ipmmu_features_rcar_gen3 = {
>>       .use_ns_alias_offset = false,
>>       .has_cache_leaf_nodes = true,
>>       .has_eight_ctx = true,
>> @@ -1088,7 +1088,10 @@ static const struct of_device_id ipmmu_o
>>               .data = &ipmmu_features_default,
>>       }, {
>>               .compatible = "renesas,ipmmu-r8a7795",
>> -             .data = &ipmmu_features_r8a7795,
>> +             .data = &ipmmu_features_rcar_gen3,
>> +     }, {
>> +             .compatible = "renesas,ipmmu-r8a7796",
>> +             .data = &ipmmu_features_rcar_gen3,
>>       }, {
>>               /* Terminator */
>>       },
>> @@ -1268,6 +1271,8 @@ IOMMU_OF_DECLARE(ipmmu_vmsa_iommu_of, "r
>>                ipmmu_vmsa_iommu_of_setup);
>>  IOMMU_OF_DECLARE(ipmmu_r8a7795_iommu_of, "renesas,ipmmu-r8a7795",
>>                ipmmu_vmsa_iommu_of_setup);
>> +IOMMU_OF_DECLARE(ipmmu_r8a7796_iommu_of, "renesas,ipmmu-r8a7796",
>> +              ipmmu_vmsa_iommu_of_setup);
>
> How about a Gen3 generic compatible string in addition to the SoC-specific
> ones ?

As you probably know, neither R-Car Gen2 nor R-Car Gen3 families are
finished evolving. Because of that I find speculating with DT compat
strings just potentially confusing with no apparent upside. Just going
with what we know (ie the part number) is more than good enough IMO.

Thanks,

/ magnus