Quoting Jorge Ramirez (2019-01-17 02:46:21) > On 1/17/19 11:08, Viresh Kumar wrote: > > On 17-01-19, 09:38, Jorge Ramirez wrote: > >> COMMON_CLK_DISABLED_UNUSED relies on the enable_count reference counter > >> to disable the clocks that were enabled by the firwmare and not by the > >> drivers. > >> > >> the cpufreq driver does not enable the cpu clock. > >> > >> so when clk_change_rate is called, the enable_count counter is not > >> incremented and therefore it just remains null since this was enabled by > >> the firmware. > >> > >> I tried doing: > >> > >> diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c > >> index e58bfcb..5a9f83e 100644 > >> --- a/drivers/cpufreq/cpufreq-dt.c > >> +++ b/drivers/cpufreq/cpufreq-dt.c > >> @@ -124,6 +124,10 @@ static int resources_available(void) > >> return ret; > >> } > >> > >> + ret = clk_prepare_enable(cpu_clk); > >> + if (ret) > >> + return ret; > >> + > >> clk_put(cpu_clk); > >> > >> name = find_supply_name(cpu_dev); > >> > >> > >> and that removed the need for CLK_IGNORE_UNUSED. But I am not sure of > >> the system wide consequences of that change to cpufreq. > > > > If the cpufreq driver enables it then it should disable it on exit as > > well, right ? And in that case if you unload your driver's module, you > > will hang the system as the clock will get disabled :) > > ah, of course, sorry was over-thinking this thing :) > > > > > Every other platform must either be marking it with CLK_IGNORE_UNUSED > > or they must be doing clk_enable from somewhere, maybe the CPU online > > path, not sure though. > > > > since this clock is enabled by the firmware, it seems to me that using > CLK_IGNORE_UNUSED remains the best option. > What do you do about CPUs being offlined? Presumably when the CPU is gone the system doesn't need to keep the clk enabled anymore.
