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

[Viresh Kumar]

On 13 May 2015 at 18:05, Sudeep Holla <sudeep.holla@xxxxxxx> 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@xxxxxxxxxx>
> Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
> Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
> ---
>  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@xxxxxxxxxx>
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