Add a helper function to check if a PRM handler/module is present.

This can be used during init time by code that depends on a particular
handler. If the handler is not present, then the code does not need to
be loaded.

Acked-by: "Rafael J. Wysocki (Intel)" <rafael@kernel.org>
Reviewed-by: "Mario Limonciello (AMD)" <superm1@kernel.org>
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
---
 drivers/acpi/prmt.c  | 6 ++++++
 include/linux/prmt.h | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/drivers/acpi/prmt.c b/drivers/acpi/prmt.c
index 6792d4385eee..7b8b5d2015ec 100644
--- a/drivers/acpi/prmt.c
+++ b/drivers/acpi/prmt.c
@@ -244,6 +244,12 @@ static struct prm_handler_info *find_prm_handler(const guid_t *guid)
 	return (struct prm_handler_info *) find_guid_info(guid, GET_HANDLER);
 }
 
+bool acpi_prm_handler_available(const guid_t *guid)
+{
+	return find_prm_handler(guid) && find_prm_module(guid);
+}
+EXPORT_SYMBOL_GPL(acpi_prm_handler_available);
+
 /* In-coming PRM commands */
 
 #define PRM_CMD_RUN_SERVICE		0
diff --git a/include/linux/prmt.h b/include/linux/prmt.h
index c53ab287e932..8cdc987de963 100644
--- a/include/linux/prmt.h
+++ b/include/linux/prmt.h
@@ -4,9 +4,11 @@
 
 #ifdef CONFIG_ACPI_PRMT
 void init_prmt(void);
+bool acpi_prm_handler_available(const guid_t *handler_guid);
 int acpi_call_prm_handler(guid_t handler_guid, void *param_buffer);
 #else
 static inline void init_prmt(void) { }
+static inline bool acpi_prm_handler_available(const guid_t *handler_guid) { return false; }
 static inline int acpi_call_prm_handler(guid_t handler_guid, void *param_buffer)
 {
 	return -EOPNOTSUPP;

-- 
2.51.0