Re: [PATCH v5 4/6] drm/panfrost: Add support for AARCH64_4K page table format

[Ariel D'Alessandro <ariel.dalessandro@collabora.com>]

Hi Steven,

On 3/31/25 8:15 AM, Steven Price wrote:
> On 24/03/2025 18:57, Ariel D'Alessandro wrote:
>> Currently, Panfrost only supports MMU configuration in "LEGACY" (as
>> Bifrost calls it) mode, a (modified) version of LPAE "Large Physical
>> Address Extension", which in Linux we've called "mali_lpae".
>>
>> This commit adds support for conditionally enabling AARCH64_4K page
>> table format. To achieve that, a "GPU optional quirks" field was added
>> to `struct panfrost_features` with the related flag.
>>
>> Note that, in order to enable AARCH64_4K mode, the GPU variant must have
>> the HW_FEATURE_AARCH64_MMU feature flag present.
>>
>> Signed-off-by: Ariel D'Alessandro <ariel.dalessandro@collabora.com>
>> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
>> Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
>> Reviewed-by: Adrián Larumbe <adrian.larumbe@collabora.com>
> 
> Reviewed-by: Steven Price <steven.price@arm.com>
> 
> (one very minor nit below)
> 
>> ---
>>   drivers/gpu/drm/panfrost/panfrost_device.h |  16 +++
>>   drivers/gpu/drm/panfrost/panfrost_mmu.c    | 140 +++++++++++++++++++--
>>   drivers/gpu/drm/panfrost/panfrost_regs.h   |  34 +++++
>>   3 files changed, 183 insertions(+), 7 deletions(-)
>>
> 
> [...]
> 
>> diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c
>> index 294f86b3c25e..ccf51fd5f9c0 100644
>> --- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
>> +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
> [...]
>> +
>> +static int panfrost_mmu_cfg_init(struct panfrost_mmu *mmu,
>> +				  enum io_pgtable_fmt fmt)
> 
> NIT: It's always hard to see in the diff, but the alignment of the
> second line is wrong. But I'll fix this up when merging.

Indeed, you're right. Thanks for the nitpick!

Happy to see this hitting drm-misc-next soon :)

-- 
Ariel D'Alessandro
Software Engineer

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