On 09/02/2025 11:11, Viken Dadhaniya wrote: >>>>>> >>>>>> Just one blank line, but anyway, this property should not be in three >>>>>> places. Do you really expect that each of serial engines within one >>>>>> GeniQUP will be configured differently by TZ? >>>>> >>>>> Yes, each SE is configured separately and it's quite frequent when >>>>> different SEs have different DMA configuration. >>>> >>>> Well, I checked at sm8550 and sm8650 and each pair of SE - which shares >>>> resources - has the same DMAs, so I would not call it frequent. Care to >>>> bring an example where same serial engines have different DMAs and >>>> different TZ? We do not talk about single QUP. >>> >>> Well, I don't have access to the latest sm8550 / sm8650 devcfg sources. >>> I checked the RB5 ones. As far as I understand out of 14 enabled SEs >>> only two are configured for the GSI DMA, others should use FIFO / SE >>> DMA. Same applies to the SM8250 MTP devices. Checking the RB1 / RB2 >>> setup also shows 3 out of 6 SEs being set for GSI. >> >> I think selecting GSI DMA is only for devices needs high speed streaming >> to the >> device, like the touch screen, using GSI DMA for random small access is >> a non-sense. >> >> But the thing is, in the TZ world the configuration was static so we had >> no choice >> of using GSI DMA when configured, but now we have the choice so we could >> totally >> reconfigure the SE with the transfer type (FIFO, SE DMA or GSI DMA) as >> runtime and >> drop this attribute. >> >> So instead of hardcoding this, add a way to dynamically select either of >> the 3 >> transfer types when firmware can be loaded from HLOS. >> >> Neil >> > > Yes, GSI DMA mode is required for specific use cases only. > > Dynamically switching from GSI mode to non-GSI mode is neither possible > nor useful. For each SE, the use case is fixed, and based on the use > case, the developer can choose the mode via the device tree property. No, it cannot. Do not describe downstream as something set in stone. Best regards, Krzysztof
