On 1/8/25 11:21, Dikshita Agarwal wrote: > > > 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. Odd, perhaps a 64 vs 32 bit issue? > Correct value would be GENMASK(31,30) + GENMASK(28,0) to set the exact bits > to get the desired value i.e 0xe0000000 -1 Honestly, in this case I would prefer to just go with the actual hex value 0xdfffffff together with an explanatory comment. Regards, Hans >> Regards, >> >> Hans >> >>> Please let me know which would be better? >>> >>> Thanks, >>> Dikshita >>> >>>> >>>> Regards, >>>> >>>> Hans >>>> >>>>> >>>>> Thanks, >>>>> Dikshita >>>>>> Nicolas >>>>>> >>>>>>> >>>>>>> Thanks, >>>>>>> Dikshita >>>>>>>> Thanks, >>>>>>>> Mauro >>>>>> >>>> >>>> >>
