[PATCH] cpufreq: exynos: Broadcast frequency change notifications for all cores

[Viresh Kumar]

On 31 January 2013 20:15, Tomasz Figa <t.figa at samsung.com> wrote:
> On Thursday 31 of January 2013 09:50:37 Viresh Kumar wrote:
>> > +               policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;

>> I couldn't understand the use of this change. Can you please explain ?
>
> All cores on Exynos SoCs share the same clock source, which means that
> they all always run at the same frequency. So setting frequency on one
> core sets the frequency on all cores and so it doesn't matter on which
> core the frequency setting operation is done.

Great, that's like most other platforms and for this you just need to set mask
of all the possible cpus (online or offline) into policy->cpus

> As you can see in include/linux/cpufreq.h:
>
> #define CPUFREQ_SHARED_TYPE_ANY  (3) /* Freq can be set from any dependent
> CPU*/
>
> which basically tells (together with rest of the patch) the cpufreq
> subsystem about what I wrote earlier.

I don't think so. Because i wasn't using it on my system and it was
working well.
Then i grepped it in kernel source

viresh at blr-linut-001:$ git grep shared_type drivers/cpufreq/
drivers/cpufreq/acpi-cpufreq.c: if (policy->shared_type !=
CPUFREQ_SHARED_TYPE_ANY)
drivers/cpufreq/acpi-cpufreq.c: policy->shared_type = perf->shared_type;
drivers/cpufreq/acpi-cpufreq.c: if (policy->shared_type ==
CPUFREQ_SHARED_TYPE_ALL ||
drivers/cpufreq/acpi-cpufreq.c:     policy->shared_type ==
CPUFREQ_SHARED_TYPE_ANY) {
drivers/cpufreq/acpi-cpufreq.c:         policy->shared_type =
CPUFREQ_SHARED_TYPE_ALL;
drivers/cpufreq/acpi-cpufreq.c:         policy->shared_type =
CPUFREQ_SHARED_TYPE_HW;
drivers/cpufreq/cpufreq-cpu0.c: policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
drivers/cpufreq/db8500-cpufreq.c:       policy->shared_type =
CPUFREQ_SHARED_TYPE_ALL;
drivers/cpufreq/omap-cpufreq.c:         policy->shared_type =
CPUFREQ_SHARED_TYPE_ANY;
drivers/cpufreq/speedstep-centrino.c:           if
(policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
drivers/cpufreq/speedstep-centrino.c:           if
(policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)

I couldn't see any core file using this stuff other than acpi-cpufreq.c,
which is for x86 only systems if i am not wrong.

@Rafael: You view on this.. ? Actually i believe it was just used by many
ARM drivers without knowing the real use of it and new drivers have just
followed it.

I can get a patch to fix it at all places if you agree.

BTW, grep in full kernel source gave, which is again acpi only:

viresh at blr-linut-001:$ git grep shared_type

arch/arm/mach-tegra/cpu-tegra.c:        policy->shared_type =
CPUFREQ_SHARED_TYPE_ALL;
drivers/acpi/processor_perflib.c:
pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ALL;
drivers/acpi/processor_perflib.c:
pr->performance->shared_type = CPUFREQ_SHARED_TYPE_HW;
drivers/acpi/processor_perflib.c:
pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ANY;
drivers/acpi/processor_perflib.c:
match_pr->performance->shared_type =
drivers/acpi/processor_perflib.c:
 pr->performance->shared_type;
drivers/acpi/processor_perflib.c:
pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ALL;
drivers/acpi/processor_throttling.c:
pthrottling->shared_type = DOMAIN_COORD_TYPE_SW_ALL;
drivers/acpi/processor_throttling.c:    pthrottling->shared_type =
pdomain->coord_type;
drivers/acpi/processor_throttling.c:
pthrottling->shared_type = DOMAIN_COORD_TYPE_SW_ALL;
drivers/acpi/processor_throttling.c:    if (p_throttling->shared_type
== DOMAIN_COORD_TYPE_SW_ANY) {
drivers/acpi/processor_throttling.c:
pthrottling->shared_type = DOMAIN_COORD_TYPE_SW_ALL;
drivers/cpufreq/acpi-cpufreq.c: if (policy->shared_type !=
CPUFREQ_SHARED_TYPE_ANY)
drivers/cpufreq/acpi-cpufreq.c: policy->shared_type = perf->shared_type;
drivers/cpufreq/acpi-cpufreq.c: if (policy->shared_type ==
CPUFREQ_SHARED_TYPE_ALL ||
drivers/cpufreq/acpi-cpufreq.c:     policy->shared_type ==
CPUFREQ_SHARED_TYPE_ANY) {
drivers/cpufreq/acpi-cpufreq.c:         policy->shared_type =
CPUFREQ_SHARED_TYPE_ALL;
drivers/cpufreq/acpi-cpufreq.c:         policy->shared_type =
CPUFREQ_SHARED_TYPE_HW;
drivers/cpufreq/cpufreq-cpu0.c: policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
drivers/cpufreq/db8500-cpufreq.c:       policy->shared_type =
CPUFREQ_SHARED_TYPE_ALL;
drivers/cpufreq/omap-cpufreq.c:         policy->shared_type =
CPUFREQ_SHARED_TYPE_ANY;
drivers/cpufreq/speedstep-centrino.c:           if
(policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
drivers/cpufreq/speedstep-centrino.c:           if
(policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
drivers/net/wireless/rtlwifi/rtl8192ce/hw.c:
rtlpcipriv->bt_coexist.bt_radio_shared_type =
drivers/net/wireless/rtlwifi/rtl8723ae/hw.c:
pcipriv->bt_coexist.bt_radio_shared_type =
drivers/net/wireless/rtlwifi/rtl8723ae/hw.c:
pcipriv->bt_coexist.bt_radio_shared_type);
drivers/net/wireless/rtlwifi/wifi.h:    u8 bt_radio_shared_type;
drivers/xen/xen-acpi-processor.c:       dst->shared_type =
_pr->performance->shared_type;
drivers/xen/xen-acpi-processor.c:
dst->shared_type = CPUFREQ_SHARED_TYPE_ALL;
drivers/xen/xen-acpi-processor.c:
dst->shared_type = CPUFREQ_SHARED_TYPE_HW;
drivers/xen/xen-acpi-processor.c:
dst->shared_type = CPUFREQ_SHARED_TYPE_ANY;
include/acpi/processor.h:       unsigned int shared_type;
include/acpi/processor.h:       unsigned int shared_type;
include/linux/cpufreq.h:        unsigned int            shared_type;
/* ANY or ALL affected CPUs
include/xen/interface/platform.h:       uint32_t shared_type;     /*
coordination type of this processor */
tools/perf/util/dwarf-aux.c:             tag == DW_TAG_shared_type);