mailbox: pcc: Add PCC request and free channel declarations

Exports pcc_mbox_request_channel() and pcc_mbox_free_channel()
declarations into a pcc.h header file.

Looks-good-to: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Hoan Tran <hotran@apm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

include/acpi/cppc_acpi.h

@@ -15,10 +15,9 @@
 #define _CPPC_ACPI_H
 
 #include <linux/acpi.h>
-#include <linux/mailbox_controller.h>
-#include <linux/mailbox_client.h>
 #include <linux/types.h>
 
+#include <acpi/pcc.h>
 #include <acpi/processor.h>
 
 /* Only support CPPCv2 for now. */
@@ -130,8 +129,4 @@ extern int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
 extern int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps);
 extern int acpi_get_psd_map(struct cpudata **);
 
-/* Methods to interact with the PCC mailbox controller. */
-extern struct mbox_chan *
-	pcc_mbox_request_channel(struct mbox_client *, unsigned int);
-
 #endif /* _CPPC_ACPI_H*/

include/acpi/pcc.h

+/*
+ * PCC (Platform Communications Channel) methods
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+
+#ifndef _PCC_H
+#define _PCC_H
+
+#include <linux/mailbox_controller.h>
+#include <linux/mailbox_client.h>
+
+#ifdef CONFIG_PCC
+extern struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
+						  int subspace_id);
+extern void pcc_mbox_free_channel(struct mbox_chan *chan);
+#else
+static inline struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
+							 int subspace_id)
+{
+	return NULL;
+}
+static inline void pcc_mbox_free_channel(struct mbox_chan *chan) { }
+#endif
+
+#endif /* _PCC_H */