Messages in this thread Patch in this message | | | From | Amit Kucheria <> | Date | Mon, 8 Aug 2016 23:32:22 +0530 | Subject | Re: [PATCH] clk: Hi6220: enable stub clock driver for ARCH_HISI |
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On Mon, Aug 8, 2016 at 9:23 PM, Daniel Thompson <daniel.thompson@linaro.org> wrote: > On 08/08/16 15:42, Amit Kucheria wrote: >> >> On Mon, Aug 8, 2016 at 12:12 PM, Leo Yan <leo.yan@linaro.org> wrote: >>> >>> Hi Amit, >>> >>> On Mon, Aug 08, 2016 at 11:23:31AM +0530, Amit Kucheria wrote: >>>> >>>> On Mon, Aug 8, 2016 at 9:07 AM, Leo Yan <leo.yan@linaro.org> wrote: >>>>> >>>>> In current kernel config 'CONFIG_STUB_CLK_HI6220' is disabled by >>>>> default, as result stub clock driver has not been registered and >>>>> CPUFreq driver cannot work. >>>> >>>> >>>> I have a related patch that has been pending for a while: >>>> https://lkml.org/lkml/2016/6/20/375 but it was tied only to the >>>> thermal driver. >>> >>> >>> I also have concern this patch may duplicate with yours. >>> >>>> Is the stub mandatory for the architecture? Will other SoCs in the >>>> family will use the same stub? >>> >>> >>> I don't think stub driver is mandartory for archtitecture and it's >>> only used by Hi6220 on Hikey. AFAIK, currently stub driver is only used >>> by CPU frequency change. >>> >>> The logic is: >>> Thermal cooling device driver >>> `-> CPUFreq DT driver >>> `-> Stub clock driver >>> >>> ARM is working on Hikey for EAS profiling, so usually the use case is >>> to enable CPUFreq driver and stub clock driver. Sometimes it only >>> need enable this driver without thermal driver; so this is why we >>> cannot rely on thermal driver to enable stub clock driver. >>> >>> I'm open-minded if you have better idea to enable it. >>> >>>>> This patch is to enable stub clock driver in config for ARCH_HISI. >>>>> >>>>> Reported-by: Dietmar Eggemann <dietmar.eggemann@arm.com> >>>>> Signed-off-by: Leo Yan <leo.yan@linaro.org> >>>>> --- >>>>> drivers/clk/hisilicon/Kconfig | 1 + >>>>> 1 file changed, 1 insertion(+) >>>>> >>>>> diff --git a/drivers/clk/hisilicon/Kconfig >>>>> b/drivers/clk/hisilicon/Kconfig >>>>> index 3f537a0..9e0a95e 100644 >>>>> --- a/drivers/clk/hisilicon/Kconfig >>>>> +++ b/drivers/clk/hisilicon/Kconfig >>>>> @@ -23,5 +23,6 @@ config RESET_HISI >>>>> config STUB_CLK_HI6220 >>>>> bool "Hi6220 Stub Clock Driver" >>>>> depends on COMMON_CLK_HI6220 && MAILBOX >>>>> + default ARCH_HISI >> >> >> Instead of forcing this up on the entire arch, why not restrict it to >> just the cpufreq driver? ARM_HISI_ACPU_CPUFREQ? > > > I'm struggling to understand the concern here. default doesn't force this > option on anything, it just sets the default. > > Personally I might prefer 'default y' because it is simpler and involves > less thinking. However the other drivers in this directory use 'default > ARCH_HISI' (i.e. they do not default on for a COMPILE_TEST) so copying their > approach is quite reasonable.
No concern actually - on the contrary, this dependency needs to be fixed urgently. Just trying to figure out if there is a way to manage the dependency chain in one place and including the root config option into defconfig.
(Thermal driver) ---- dep ---> (cpufreq driver) ----- dep ---> (hi2660 clock stub driver) ---- dep -----> (common hi6220 clock driver)
My earlier patch focused on enabling the stub driver in the case the thermal driver was enabled (and subsequently turning on HISI_THERMAL in defconfig). The EAS profiling usecase to prevent thermal-throttling from kicking in is a bad default to have in the kernel, IMO - it can be easily achieved by just changing the thermal thresholds.
Something like the following, with HISI_THERMAL added to defconfig would give a "stable" kernel on Hikey.
diff --git i/drivers/thermal/Kconfig w/drivers/thermal/Kconfig index 2d702ca..77597a5 100644 --- i/drivers/thermal/Kconfig +++ w/drivers/thermal/Kconfig @@ -177,8 +177,11 @@ config THERMAL_EMULATION
config HISI_THERMAL tristate "Hisilicon thermal driver" - depends on (ARCH_HISI && CPU_THERMAL && OF) || COMPILE_TEST + depends on (ARCH_HISI && OF) || COMPILE_TEST depends on HAS_IOMEM + select CPU_THERMAL + select CPUFREQ_DT + select STUB_CLK_HI6220 help Enable this to plug hisilicon's thermal sensor driver into the Linux thermal framework. cpufreq is used as the cooling device to throttle
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