ACPI: CPPC: Add emtpy stubs of functions for CONFIG_ACPI_CPPC_LIB unset

For convenience, add empty stubs of library functions defined in
cppc_acpi.c for the CONFIG_ACPI_CPPC_LIB unset case.

Because one of them needs to return CPUFREQ_ETERNAL, include
linux/cpufreq.h into the CPPC library header file and drop the
direct inclusion of it from cppc_acpi.c.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>

drivers/acpi/cppc_acpi.c

@@ -33,7 +33,6 @@
 
 #define pr_fmt(fmt)	"ACPI CPPC: " fmt
 
-#include <linux/cpufreq.h>
 #include <linux/delay.h>
 #include <linux/iopoll.h>
 #include <linux/ktime.h>

include/acpi/cppc_acpi.h

@@ -11,6 +11,7 @@
 #define _CPPC_ACPI_H
 
 #include <linux/acpi.h>
+#include <linux/cpufreq.h>
 #include <linux/types.h>
 
 #include <acpi/pcc.h>
@@ -132,6 +133,7 @@ struct cppc_cpudata {
 	cpumask_var_t shared_cpu_map;
 };
 
+#ifdef CONFIG_ACPI_CPPC_LIB
 extern int cppc_get_desired_perf(int cpunum, u64 *desired_perf);
 extern int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs);
 extern int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
@@ -142,5 +144,43 @@ extern unsigned int cppc_get_transition_latency(int cpu);
 extern bool cpc_ffh_supported(void);
 extern int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val);
 extern int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val);
+#else /* !CONFIG_ACPI_CPPC_LIB */
+static inline int cppc_get_desired_perf(int cpunum, u64 *desired_perf)
+{
+	return -ENOTSUPP;
+}
+static inline int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
+{
+	return -ENOTSUPP;
+}
+static inline int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
+{
+	return -ENOTSUPP;
+}
+static inline int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps)
+{
+	return -ENOTSUPP;
+}
+static inline bool acpi_cpc_valid(void)
+{
+	return false;
+}
+static inline unsigned int cppc_get_transition_latency(int cpu)
+{
+	return CPUFREQ_ETERNAL;
+}
+static inline bool cpc_ffh_supported(void)
+{
+	return false;
+}
+static inline int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val)
+{
+	return -ENOTSUPP;
+}
+static inline int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val)
+{
+	return -ENOTSUPP;
+}
+#endif /* !CONFIG_ACPI_CPPC_LIB */
 
 #endif /* _CPPC_ACPI_H*/