Messages in this thread | | | Date | Mon, 25 Jul 2022 11:16:38 +0800 | Subject | Re: [PATCH 1/2] LoongArch: Remove clock setting during cpu hotplug stage | From | maobibo <> |
| |
在 2022/7/22 16:10, WANG Xuerui 写道: > On 2022/7/20 15:21, Bibo Mao wrote: >> On physical machine we can save power by disabling clock of hot removed cpu. >> However there will be problem, since different platforms have different clock >> setting methods, the code is platform relative. Also it can be in firmware/pmu >> compoments or cpu regulator driver, rather than general loongarch cpu booting >> flow. >> >> Also on qemu virt machine, device clock/freq setting is not >> emulated, there is no such registers. >> >> This patch removes hard-coded register accessing in generic >> loongarch cpu boot flow. > > Improving a little on the wording (mostly fixing eyesore Chinglish): > > "On physical machine we can save power by disabling clock of hot removed cpu. However as different platforms require different methods to configure clocks, the code is platform-specific, and probably belongs to firmware/pmu or cpu regulator, rather than generic arch/loongarch code. > > Also, there is no such register on QEMU virt machine since the clock/frequency regulation is not emulated. > > This patch removes the hard-coded clock register accesses in generic loongarch cpu hotplug flow." > Xuerui,
Thanks for reviewing my patch, I will modify the issue in next patch.
regards bibo, mao
>> >> Signed-off-by: Bibo Mao <maobibo@loongson.cn> >> --- >> arch/loongarch/kernel/smp.c | 29 ----------------------------- >> include/linux/cpuhotplug.h | 1 - >> 2 files changed, 30 deletions(-) >> >> diff --git a/arch/loongarch/kernel/smp.c b/arch/loongarch/kernel/smp.c >> index 73cec62504fb..98b3e059d344 100644 >> --- a/arch/loongarch/kernel/smp.c >> +++ b/arch/loongarch/kernel/smp.c >> @@ -359,35 +359,6 @@ void play_dead(void) >> play_dead_uncached(state_addr); >> } >> -static int loongson3_enable_clock(unsigned int cpu) >> -{ >> - uint64_t core_id = cpu_data[cpu].core; >> - uint64_t package_id = cpu_data[cpu].package; >> - >> - LOONGSON_FREQCTRL(package_id) |= 1 << (core_id * 4 + 3); >> - >> - return 0; >> -} >> - >> -static int loongson3_disable_clock(unsigned int cpu) >> -{ >> - uint64_t core_id = cpu_data[cpu].core; >> - uint64_t package_id = cpu_data[cpu].package; >> - >> - LOONGSON_FREQCTRL(package_id) &= ~(1 << (core_id * 4 + 3)); >> - >> - return 0; >> -} >> - >> -static int register_loongson3_notifier(void) >> -{ >> - return cpuhp_setup_state_nocalls(CPUHP_LOONGARCH_SOC_PREPARE, >> - "loongarch/loongson:prepare", >> - loongson3_enable_clock, >> - loongson3_disable_clock); >> -} >> -early_initcall(register_loongson3_notifier); >> - >> #endif >> /* >> diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h >> index 19f0dbfdd7fe..b66c5f389159 100644 >> --- a/include/linux/cpuhotplug.h >> +++ b/include/linux/cpuhotplug.h >> @@ -130,7 +130,6 @@ enum cpuhp_state { >> CPUHP_ZCOMP_PREPARE, >> CPUHP_TIMERS_PREPARE, >> CPUHP_MIPS_SOC_PREPARE, >> - CPUHP_LOONGARCH_SOC_PREPARE, >> CPUHP_BP_PREPARE_DYN, >> CPUHP_BP_PREPARE_DYN_END = CPUHP_BP_PREPARE_DYN + 20, >> CPUHP_BRINGUP_CPU, > > Seems good. I should have noticed earlier the fact the clock control registers are, in every regard, model-specific, thus not appropriate for arch/loongarch. Proper drivers should be added afterwards, though I assume you must internally have something like that already. > > Reviewed-by: WANG Xuerui <git@xen0n.name>
| |