On 1/8/2025 2:25 PM, Hans Verkuil wrote: > 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). > I tested this some more, and seems ~BIT(29) doesn't work, as its still conflicting with the register space. Correct value would be GENMASK(31,30) + GENMASK(28,0) to set the exact bits to get the desired value i.e 0xe0000000 -1 > Regards, > > Hans > >> Please let me know which would be better? >> >> Thanks, >> Dikshita >> >>> >>> Regards, >>> >>> Hans >>> >>>> >>>> Thanks, >>>> Dikshita >>>>> Nicolas >>>>> >>>>>> >>>>>> Thanks, >>>>>> Dikshita >>>>>>> Thanks, >>>>>>> Mauro >>>>> >>> >>> >
