On 08/01/2025 09:51, Dikshita Agarwal wrote: > > > On 1/8/2025 1:17 PM, Hans Verkuil wrote: >> On 08/01/2025 08:43, Dikshita Agarwal wrote: >>> >>> >>> On 1/7/2025 7:27 PM, Nicolas Dufresne wrote: >>>> Le lundi 23 décembre 2024 à 16:21 +0530, Dikshita Agarwal a écrit : >>>>> >>>>> On 12/23/2024 4:00 PM, Mauro Carvalho Chehab wrote: >>>>>> Em Thu, 12 Dec 2024 17:21:49 +0530 >>>>>> Dikshita Agarwal <quic_dikshita@xxxxxxxxxxx> escreveu: >>>>>> >>>>>>> + .dma_mask = GENMASK(31, 29) - 1, >>>>>> >>>>>> Setting a mask to GENMASK() - 1 sounds weird. Is it really what you want? >>>>>> I so, why? >>>>>> >>>>> Hi Mauro, >>>>> >>>>> the value of this dma mask should be 0xe0000000 -1. >>>>> >>>>> The background for the same is, 0xe0000000 onward memory space is allocated >>>>> for IO register space so we are restricting the driver buffer allocations >>>>> to 0xe0000000 - 1. >>>>> >>>>> Based on the comments received in the past, we are using GENMASK to >>>>> generate 0xe0000000. >>>>> >>>>> Does this answer your query or I missed something? >>>> >>>> I'm not sure it will do what you want. (0xe0000000 -1) matches ~BIT(29). Perhaps >>>> you wanted to use ~0xe0000000. >>>> >>> value of dma mask is coming as expected with GENMASK(31, 29) - 1 >>> >>> qcom-iris aa00000.video-codec: dma_mask DFFFFFFF (0xe0000000 -1) >> >> Isn't this just the equivalent of GENMASK(28, 0)? Can't you use that? Too early in the morning, this suggestion was clearly wrong. >> >> It's much easier to understand than GENMASK()-1. > > Sure, I can use either ~GENMASK(29, 29) or ~BIT(29), ~BIT(29). It's really weird to just disable a single bit, so I think some comments explaining why this mask is needed would be good (if there aren't comments already). Regards, Hans > Please let me know which would be better? > > Thanks, > Dikshita > >> >> Regards, >> >> Hans >> >>> >>> Thanks, >>> Dikshita >>>> Nicolas >>>> >>>>> >>>>> Thanks, >>>>> Dikshita >>>>>> Thanks, >>>>>> Mauro >>>> >> >>
