cpufreq,arm,arm64: restructure definitions of arch_set_freq_scale()

Compared to other arch_* functions, arch_set_freq_scale() has an atypical
weak definition that can be replaced by a strong architecture specific
implementation.

The more typical support for architectural functions involves defining
an empty stub in a header file if the symbol is not already defined in
architecture code. Some examples involve:
- #define arch_scale_freq_capacity topology_get_freq_scale
- #define arch_scale_freq_invariant topology_scale_freq_invariant
- #define arch_scale_cpu_capacity topology_get_cpu_scale
- #define arch_update_cpu_topology topology_update_cpu_topology
- #define arch_scale_thermal_pressure topology_get_thermal_pressure
- #define arch_set_thermal_pressure topology_set_thermal_pressure

Bring arch_set_freq_scale() in line with these functions by renaming it to
topology_set_freq_scale() in the arch topology driver, and by defining the
arch_set_freq_scale symbol to point to the new function for arm and arm64.

While there are other users of the arch_topology driver, this patch defines
arch_set_freq_scale for arm and arm64 only, due to their existing
definitions of arch_scale_freq_capacity. This is the getter function of the
frequency invariance scale factor and without a getter function, the
setter function - arch_set_freq_scale() has not purpose.

Signed-off-by: Ionela Voinescu <[e-mail]>
Acked-by: Viresh Kumar <[e-mail]>
Acked-by: Catalin Marinas <[e-mail]>
Acked-by: Sudeep Holla <[e-mail]> (BL_SWITCHER and topology parts)
Signed-off-by: Rafael J. Wysocki <[e-mail]>

arch/arm/include/asm/topology.h

···
 #include <linux/arch_topology.h>
 
 /* Replace task scheduler's default frequency-invariant accounting */
+#define arch_set_freq_scale topology_set_freq_scale
 #define arch_scale_freq_capacity topology_get_freq_scale
 #define arch_scale_freq_invariant topology_scale_freq_invariant
 

arch/arm64/include/asm/topology.h

···
 #endif /* CONFIG_ARM64_AMU_EXTN */
 
 /* Replace task scheduler's default frequency-invariant accounting */
+#define arch_set_freq_scale topology_set_freq_scale
 #define arch_scale_freq_capacity topology_get_freq_scale
 #define arch_scale_freq_invariant topology_scale_freq_invariant
 

drivers/base/arch_topology.c

···
 }
 DEFINE_PER_CPU(unsigned long, freq_scale) = SCHED_CAPACITY_SCALE;
 
-void arch_set_freq_scale(const struct cpumask *cpus, unsigned long cur_freq,
-			 unsigned long max_freq)
+void topology_set_freq_scale(const struct cpumask *cpus, unsigned long cur_freq,
+			     unsigned long max_freq)
 {
 	unsigned long scale;
 	int i;

drivers/cpufreq/cpufreq.c

···
 }
 EXPORT_SYMBOL_GPL(get_cpu_idle_time);
 
-__weak void arch_set_freq_scale(const struct cpumask *cpus,
-				unsigned long cur_freq,
-				unsigned long max_freq)
-{
-}
-EXPORT_SYMBOL_GPL(arch_set_freq_scale);
-
 /*
  * This is a generic cpufreq init() routine which can be used by cpufreq
  * drivers of SMP systems. It will do following:

include/linux/arch_topology.h

···
 	return per_cpu(freq_scale, cpu);
 }
 
+void topology_set_freq_scale(const struct cpumask *cpus, unsigned long cur_freq,
+			     unsigned long max_freq);
 bool topology_scale_freq_invariant(void);
 
 bool arch_freq_counters_available(const struct cpumask *cpus);

include/linux/cpufreq.h

···
 extern void arch_freq_prepare_all(void);
 extern unsigned int arch_freq_get_on_cpu(int cpu);
 
-extern void arch_set_freq_scale(const struct cpumask *cpus,
-				unsigned long cur_freq,
-				unsigned long max_freq);
+#ifndef arch_set_freq_scale
+static __always_inline
+void arch_set_freq_scale(const struct cpumask *cpus,
+			 unsigned long cur_freq,
+			 unsigned long max_freq)
+{
+}
+#endif
 
 /* the following are really really optional */
 extern struct freq_attr cpufreq_freq_attr_scaling_available_freqs;