On Thu, Nov 17, 2022 at 06:08:41PM +0530, Manivannan Sadhasivam wrote: [...] > > AFAIK, OPP framework needs to know the current frequency of the device it is > dealing with for setting the device's OPP. So it uses clk_get_rate() of the > first clock of the device. If the clock is not available, then it uses the > frequency in the first entry of the OPP table (since it is going to be the > minimum freq of the device). > It has been a while since I followed OPP. Thanks for all the info, helped me get updated without looking at the code in detail. > As you can see, the clk_get_rate() is eminent for switching the OPPs and since > OPP framework doesn't know what device it is dealing with, it cannot use > cpufreq_get(). > Agreed. I had assumed the qcom-cpufreq-hw as setting cpufreq directly pocking the hardware but now I see it is using opp library to set some additional policy. > Is SCMI node itself has the OPP tables? Or the consumer nodes of the SCMI? > No, OPPs are read from the f/w and we just use OPP APIs to register them. But we don't use OPP library to set the performance. > TLDR; If you tell OPP framework to set a new OPP for a device, it needs to the > know the current frequency of the device. And it is not manadatory now, but in > the future maybe. > Hmm, good to know. I prefer it is not coupled with clocks and have some alternative mechanism that is suitable for performance domains and don't enforce the use of clock bindings and clk framework unnecessarily. -- Regards, Sudeep`
