acpi: Move the table-finding functions into the libary
This is useful for other features. Move the function into library code
so it can be used outside just the 'acpi' command.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/lib/acpi/acpi.c b/lib/acpi/acpi.c
new file mode 100644
index 0000000..14b1575
--- /dev/null
+++ b/lib/acpi/acpi.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Utility functions for ACPI
+ *
+ * Copyright 2023 Google LLC
+ */
+
+#include <common.h>
+#include <mapmem.h>
+#include <acpi/acpi_table.h>
+#include <asm/global_data.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct acpi_table_header *acpi_find_table(const char *sig)
+{
+ struct acpi_rsdp *rsdp;
+ struct acpi_rsdt *rsdt;
+ int len, i, count;
+
+ rsdp = map_sysmem(gd_acpi_start(), 0);
+ if (!rsdp)
+ return NULL;
+ rsdt = map_sysmem(rsdp->rsdt_address, 0);
+ len = rsdt->header.length - sizeof(rsdt->header);
+ count = len / sizeof(u32);
+ for (i = 0; i < count; i++) {
+ struct acpi_table_header *hdr;
+
+ hdr = map_sysmem(rsdt->entry[i], 0);
+ if (!memcmp(hdr->signature, sig, ACPI_NAME_LEN))
+ return hdr;
+ if (!memcmp(hdr->signature, "FACP", ACPI_NAME_LEN)) {
+ struct acpi_fadt *fadt = (struct acpi_fadt *)hdr;
+
+ if (!memcmp(sig, "DSDT", ACPI_NAME_LEN) && fadt->dsdt)
+ return map_sysmem(fadt->dsdt, 0);
+ if (!memcmp(sig, "FACS", ACPI_NAME_LEN) &&
+ fadt->firmware_ctrl)
+ return map_sysmem(fadt->firmware_ctrl, 0);
+ }
+ }
+
+ return NULL;
+}