Re: [PATCH 4/5] cpufreq: loongson3: Use global physical CPU ID in get/target callbacks

[Huacai Chen]

Hi, Zhongqiu,

On Thu, Aug 20, 2026 at 8:24 PM Zhongqiu Han
<zhongqiu.han@xxxxxxxxxxxxxxxx> wrote:
>
> On 8/18/2026 8:39 PM, Huacai Chen wrote:
> > Our server productions (e.g. Loongson-3D6000/3E6000) can have discrete
> > global physical CPU IDs while the core ID inside the packages are always
> > continuous. In these cases we should use global physical CPU IDs to get
> > and set frequencies.
> >
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Hongliang Wang <wanghongliang@xxxxxxxxxxx>
> > Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
> > ---
> >   drivers/cpufreq/loongson3_cpufreq.c | 20 +++++++++++---------
> >   1 file changed, 11 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/cpufreq/loongson3_cpufreq.c b/drivers/cpufreq/loongson3_cpufreq.c
> > index e3cd78a5ab18..c75c0e30e881 100644
> > --- a/drivers/cpufreq/loongson3_cpufreq.c
> > +++ b/drivers/cpufreq/loongson3_cpufreq.c
> > @@ -219,38 +219,40 @@ static inline int do_service_request(u32 id, u32 info, u32 cmd, u32 val, u32 ext
> >
> >   static unsigned int loongson3_cpufreq_get(unsigned int cpu)
> >   {
> > -     int ret;
> > +     int ret, core = cpu_logical_map(cpu);
> >
> > -     ret = do_service_request(cpu, FREQ_INFO_TYPE_FREQ, CMD_GET_FREQ_INFO, 0, 0);
> > +     ret = do_service_request(core, FREQ_INFO_TYPE_FREQ, CMD_GET_FREQ_INFO, 0, 0);
>
> As patch 5/5 changelog:
>
> "However, IOCSR read/write can only perform on the current node, while
> sometimes we want to perform on other nodes"
>
> However, patch 4/5 starts passing the global CPU number without updating
> do_service_request(), which is only changed in patch 5/5. Doesn't that
> mean patch 4/5 is broken on its own?
Cross-node accesses need the whole of this series. So:

For single node machines, with or without this patch are both correct.

For multi-nodes machines, this patch cannot solve all problems, but
doesn't make things worse.

>
> >
> >       return ret * KILO;
> >   }
> >
>
> A separate issue， do_service_request() can return errno such as -EPERM,
> it will cause .get() func return a large unsigned integer value.
Yes, we need "return (ret < 0) ? 0 : ret * KILO" here.


Huacai

>
>
> >   static int loongson3_cpufreq_target(struct cpufreq_policy *policy, unsigned int index)
> >   {
> > -     int ret;
> > +     int ret, core = cpu_logical_map(policy->cpu);
> >
> > -     ret = do_service_request(cpu_data[policy->cpu].core,
> > -                              FREQ_INFO_TYPE_LEVEL, CMD_SET_FREQ_INFO, index, 0);
> > +     ret = do_service_request(core, FREQ_INFO_TYPE_LEVEL, CMD_SET_FREQ_INFO,
> > +                              index, 0);
> >
> >       return (ret >= 0) ? 0 : ret;
> >   }
> >
> >   static int configure_freq_table(int cpu)
> >   {
> > -     int i, ret, boost_level, max_level, freq_level;
> > +     int i, ret, core, boost_level, max_level, freq_level;
> >       struct platform_device *pdev = cpufreq_get_driver_data();
> >       struct loongson3_freq_data *data;
> >
> >       if (per_cpu(freq_data, cpu))
> >               return 0;
> >
> > -     ret = do_service_request(cpu, 0, CMD_GET_FREQ_LEVEL_NUM, 0, 0);
> > +     core = cpu_logical_map(cpu);
> > +
> > +     ret = do_service_request(core, 0, CMD_GET_FREQ_LEVEL_NUM, 0, 0);
> >       if (ret < 0)
> >               return ret;
> >       max_level = ret;
> >
> > -     ret = do_service_request(cpu, 0, CMD_GET_FREQ_BOOST_LEVEL, 0, 0);
> > +     ret = do_service_request(core, 0, CMD_GET_FREQ_BOOST_LEVEL, 0, 0);
> >       if (ret < 0)
> >               return ret;
> >       boost_level = ret;
> > @@ -263,7 +265,7 @@ static int configure_freq_table(int cpu)
> >       data->def_freq_level = boost_level - 1;
> >
> >       for (i = 0; i < freq_level; i++) {
> > -             ret = do_service_request(cpu, FREQ_INFO_TYPE_FREQ, CMD_GET_FREQ_LEVEL_INFO, i, 0);
> > +             ret = do_service_request(core, FREQ_INFO_TYPE_FREQ, CMD_GET_FREQ_LEVEL_INFO, i, 0);
> >               if (ret < 0) {
> >                       devm_kfree(&pdev->dev, data);
> >                       return ret;
>
>
> --
> Thx and BRs,
> Zhongqiu Han
>