Re: [PATCH v2] cpufreq: arm_big_little: remove compile-time dependency on BIG_LITTLE

["Rafael J. Wysocki" <rjw@rjwysocki.net>]

On Wednesday, May 13, 2015 06:30:23 PM Viresh Kumar wrote:
> On 13 May 2015 at 18:05, Sudeep Holla <sudeep.holla@arm.com> wrote:
> > With the addition of switcher code, there's compile-time dependency on
> > BIG_LITTLE to get arm_big_little driver compiling on ARM64. Since ARM64
> > will never add support for bL switcher, it's better to remove the
> > dependency so that the driver can be reused on ARM64 platforms.
> >
> > This patch adds stubs to remove BIG_LITTLE dependency in the driver.
> >
> > Cc: Viresh Kumar <viresh.kumar@linaro.org>
> > Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> > ---
> >  drivers/cpufreq/Kconfig.arm      |  2 +-
> >  drivers/cpufreq/arm_big_little.c | 27 ++++++++++++++++++++++-----
> >  2 files changed, 23 insertions(+), 6 deletions(-)
> >
> > Changes v1->v2: replaced BL_SWITCHER with BIG_LITTLE in the title and
> >                 commit log as suggested by Viresh
> >
> > Hi Viresh,
> >
> > As replied in the thread, I have retained one change which you suspected
> > as not necessary, in order to fix the warning we get.
> >
> > Regards,
> > Sudeep
> >
> >
> > diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> > index 4f3dbc8cf729..611cb09239eb 100644
> > --- a/drivers/cpufreq/Kconfig.arm
> > +++ b/drivers/cpufreq/Kconfig.arm
> > @@ -5,7 +5,7 @@
> >  # big LITTLE core layer and glue drivers
> >  config ARM_BIG_LITTLE_CPUFREQ
> >         tristate "Generic ARM big LITTLE CPUfreq driver"
> > -       depends on ARM && BIG_LITTLE && ARM_CPU_TOPOLOGY && HAVE_CLK
> > +       depends on (ARM_CPU_TOPOLOGY || ARM64) && HAVE_CLK
> >         select PM_OPP
> >         help
> >           This enables the Generic CPUfreq driver for ARM big.LITTLE platforms.
> > diff --git a/drivers/cpufreq/arm_big_little.c b/drivers/cpufreq/arm_big_little.c
> > index e4d75ca9f3b0..f1e42f8ce0fc 100644
> > --- a/drivers/cpufreq/arm_big_little.c
> > +++ b/drivers/cpufreq/arm_big_little.c
> > @@ -31,7 +31,6 @@
> >  #include <linux/slab.h>
> >  #include <linux/topology.h>
> >  #include <linux/types.h>
> > -#include <asm/bL_switcher.h>
> >
> >  #include "arm_big_little.h"
> >
> > @@ -41,12 +40,16 @@
> >  #define MAX_CLUSTERS   2
> >
> >  #ifdef CONFIG_BL_SWITCHER
> > +#include <asm/bL_switcher.h>
> >  static bool bL_switching_enabled;
> >  #define is_bL_switching_enabled()      bL_switching_enabled
> >  #define set_switching_enabled(x)       (bL_switching_enabled = (x))
> >  #else
> >  #define is_bL_switching_enabled()      false
> >  #define set_switching_enabled(x)       do { } while (0)
> > +#define bL_switch_request(...)         do { } while (0)
> > +#define bL_switcher_put_enabled()      do { } while (0)
> > +#define bL_switcher_get_enabled()      do { } while (0)
> >  #endif
> >
> >  #define ACTUAL_FREQ(cluster, freq)  ((cluster == A7_CLUSTER) ? freq << 1 : freq)
> > @@ -513,6 +516,7 @@ static struct cpufreq_driver bL_cpufreq_driver = {
> >         .attr                   = cpufreq_generic_attr,
> >  };
> >
> > +#ifdef CONFIG_BL_SWITCHER
> >  static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb,
> >                                         unsigned long action, void *_arg)
> >  {
> > @@ -545,6 +549,20 @@ static struct notifier_block bL_switcher_notifier = {
> >         .notifier_call = bL_cpufreq_switcher_notifier,
> >  };
> >
> > +static int __bLs_register_notifier(void)
> > +{
> > +       return bL_switcher_register_notifier(&bL_switcher_notifier);
> > +}
> > +
> > +static int __bLs_unregister_notifier(void)
> > +{
> > +       return bL_switcher_unregister_notifier(&bL_switcher_notifier);
> > +}
> > +#else
> > +static int __bLs_register_notifier(void) { return 0; }
> > +static int __bLs_unregister_notifier(void) { return 0; }
> > +#endif
> > +
> >  int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
> >  {
> >         int ret, i;
> > @@ -562,8 +580,7 @@ int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
> >
> >         arm_bL_ops = ops;
> >
> > -       ret = bL_switcher_get_enabled();
> > -       set_switching_enabled(ret);
> > +       set_switching_enabled(bL_switcher_get_enabled());
> >
> >         for (i = 0; i < MAX_CLUSTERS; i++)
> >                 mutex_init(&cluster_lock[i]);
> > @@ -574,7 +591,7 @@ int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
> >                                 __func__, ops->name, ret);
> >                 arm_bL_ops = NULL;
> >         } else {
> > -               ret = bL_switcher_register_notifier(&bL_switcher_notifier);
> > +               ret = __bLs_register_notifier();
> >                 if (ret) {
> >                         cpufreq_unregister_driver(&bL_cpufreq_driver);
> >                         arm_bL_ops = NULL;
> > @@ -598,7 +615,7 @@ void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops)
> >         }
> >
> >         bL_switcher_get_enabled();
> > -       bL_switcher_unregister_notifier(&bL_switcher_notifier);
> > +       __bLs_unregister_notifier();
> >         cpufreq_unregister_driver(&bL_cpufreq_driver);
> >         bL_switcher_put_enabled();
> >         pr_info("%s: Un-registered platform driver: %s\n", __func__,
> 
> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

Queued up for 4.2, thanks!


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.