On 15.06.2023 02:49, Stephen Boyd wrote: > Quoting Konrad Dybcio (2023-06-14 11:04:19) >> This series reshuffles things around, moving the management of SMD RPM >> bus clocks to the interconnect framework where they belong. This helps >> us solve a couple of issues: >> >> 1. We can work towards unused clk cleanup of RPMCC without worrying >> about it killing some NoC bus, resulting in the SoC dying. >> Deasserting actually unused RPM clocks (among other things) will >> let us achieve "true SoC-wide power collapse states", also known as >> VDD_LOW and VDD_MIN. >> >> 2. We no longer have to keep tons of quirky bus clock ifs in the icc >> driver. You either have a RPM clock and call "rpm set rate" or you >> have a single non-RPM clock (like AHB_CLK_SRC) or you don't have any. >> >> 3. There's less overhead - instead of going through layers and layers of >> the CCF, ratesetting comes down to calling max() and sending a single >> RPM message. ICC is very very dynamic so that's a big plus. >> >> The clocks still need to be vaguely described in the clk-smd-rpm driver, >> as it gives them an initial kickoff, before actually telling RPM to >> enable DVFS scaling. After RPM receives that command, all clocks that >> have not been assigned a rate are considered unused and are shut down >> in hardware, leading to the same issue as described in point 1. > > Why can't we move the enable of DVFS scaling call to the interconnect > driver as well? We want the clk driver to not reference the interconnect > resources at all. That would result in no rpmcc ratesetting on platforms without a functional interconnect driver. The DVFS call concerns both bus and !bus clocks. Konrad
