1 files changed, 122 insertions, 0 deletions
diff --git a/drivers/acpi/acpica/tbfind.c b/drivers/acpi/acpica/tbfind.c
new file mode 100644
index 000000000..c31a5ddb0
--- /dev/null
+++ b/drivers/acpi/acpica/tbfind.c
@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
+/******************************************************************************
+ *
+ * Module Name: tbfind   - find table
+ *
+ * Copyright (C) 2000 - 2022, Intel Corp.
+ *
+ *****************************************************************************/
+
+#include <acpi/acpi.h>
+#include "accommon.h"
+#include "actables.h"
+
+#define _COMPONENT          ACPI_TABLES
+ACPI_MODULE_NAME("tbfind")
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_tb_find_table
+ *
+ * PARAMETERS:  signature           - String with ACPI table signature
+ *              oem_id              - String with the table OEM ID
+ *              oem_table_id        - String with the OEM Table ID
+ *              table_index         - Where the table index is returned
+ *
+ * RETURN:      Status and table index
+ *
+ * DESCRIPTION: Find an ACPI table (in the RSDT/XSDT) that matches the
+ *              Signature, OEM ID and OEM Table ID. Returns an index that can
+ *              be used to get the table header or entire table.
+ *
+ ******************************************************************************/
+acpi_status
+acpi_tb_find_table(char *signature,
+		   char *oem_id, char *oem_table_id, u32 *table_index)
+{
+	acpi_status status = AE_OK;
+	struct acpi_table_header header;
+	u32 i;
+
+	ACPI_FUNCTION_TRACE(tb_find_table);
+
+	/* Validate the input table signature */
+
+	if (!acpi_ut_valid_nameseg(signature)) {
+		return_ACPI_STATUS(AE_BAD_SIGNATURE);
+	}
+
+	/* Don't allow the OEM strings to be too long */
+
+	if ((strlen(oem_id) > ACPI_OEM_ID_SIZE) ||
+	    (strlen(oem_table_id) > ACPI_OEM_TABLE_ID_SIZE)) {
+		return_ACPI_STATUS(AE_AML_STRING_LIMIT);
+	}
+
+	/* Normalize the input strings */
+
+	memset(&header, 0, sizeof(struct acpi_table_header));
+	ACPI_COPY_NAMESEG(header.signature, signature);
+	strncpy(header.oem_id, oem_id, ACPI_OEM_ID_SIZE);
+	strncpy(header.oem_table_id, oem_table_id, ACPI_OEM_TABLE_ID_SIZE);
+
+	/* Search for the table */
+
+	(void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES);
+	for (i = 0; i < acpi_gbl_root_table_list.current_table_count; ++i) {
+		if (memcmp(&(acpi_gbl_root_table_list.tables[i].signature),
+			   header.signature, ACPI_NAMESEG_SIZE)) {
+
+			/* Not the requested table */
+
+			continue;
+		}
+
+		/* Table with matching signature has been found */
+
+		if (!acpi_gbl_root_table_list.tables[i].pointer) {
+
+			/* Table is not currently mapped, map it */
+
+			status =
+			    acpi_tb_validate_table(&acpi_gbl_root_table_list.
+						   tables[i]);
+			if (ACPI_FAILURE(status)) {
+				goto unlock_and_exit;
+			}
+
+			if (!acpi_gbl_root_table_list.tables[i].pointer) {
+				continue;
+			}
+		}
+
+		/* Check for table match on all IDs */
+
+		if (!memcmp
+		    (acpi_gbl_root_table_list.tables[i].pointer->signature,
+		     header.signature, ACPI_NAMESEG_SIZE) && (!oem_id[0]
+							      ||
+							      !memcmp
+							      (acpi_gbl_root_table_list.
+							       tables[i].
+							       pointer->oem_id,
+							       header.oem_id,
+							       ACPI_OEM_ID_SIZE))
+		    && (!oem_table_id[0]
+			|| !memcmp(acpi_gbl_root_table_list.tables[i].pointer->
+				   oem_table_id, header.oem_table_id,
+				   ACPI_OEM_TABLE_ID_SIZE))) {
+			*table_index = i;
+
+			ACPI_DEBUG_PRINT((ACPI_DB_TABLES,
+					  "Found table [%4.4s]\n",
+					  header.signature));
+			goto unlock_and_exit;
+		}
+	}
+	status = AE_NOT_FOUND;
+
+unlock_and_exit:
+	(void)acpi_ut_release_mutex(ACPI_MTX_TABLES);
+	return_ACPI_STATUS(status);
+}