acpi: Support generation of a scope

Add a function to write a scope to the generated ACPI code.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
[bmeng: Fix build failures on Sandbox]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/include/acpi/acpigen.h b/include/acpi/acpigen.h
index c6644bc..4a60612 100644
--- a/include/acpi/acpigen.h
+++ b/include/acpi/acpigen.h
@@ -31,6 +31,7 @@
 	DWORD_PREFIX		= 0x0c,
 	STRING_PREFIX		= 0x0d,
 	QWORD_PREFIX		= 0x0e,
+	SCOPE_OP		= 0x10,
 	BUFFER_OP		= 0x11,
 	PACKAGE_OP		= 0x12,
 	METHOD_OP		= 0x14,
@@ -262,6 +263,14 @@
 void acpigen_write_name(struct acpi_ctx *ctx, const char *namepath);
 
 /**
+ * acpigen_write_scope() - Write a scope
+ *
+ * @ctx: ACPI context pointer
+ * @scope: Scope to write (e.g. "\\_SB.ABCD")
+ */
+void acpigen_write_scope(struct acpi_ctx *ctx, const char *scope);
+
+/**
  * acpigen_write_uuid() - Write a UUID
  *
  * This writes out a UUID in the format used by ACPI, with a BUFFER_OP prefix.
diff --git a/lib/acpi/acpigen.c b/lib/acpi/acpigen.c
index 45216c1..1e0a489 100644
--- a/lib/acpi/acpigen.c
+++ b/lib/acpi/acpigen.c
@@ -258,6 +258,13 @@
 	acpigen_emit_namestring(ctx, namepath);
 }
 
+void acpigen_write_scope(struct acpi_ctx *ctx, const char *scope)
+{
+	acpigen_emit_byte(ctx, SCOPE_OP);
+	acpigen_write_len_f(ctx);
+	acpigen_emit_namestring(ctx, scope);
+}
+
 static void acpigen_write_method_internal(struct acpi_ctx *ctx,
 					  const char *name, uint flags)
 {
diff --git a/test/dm/acpi.c b/test/dm/acpi.c
index 7768f95..b94c4ba 100644
--- a/test/dm/acpi.c
+++ b/test/dm/acpi.c
@@ -20,9 +20,8 @@
 #include <dm/acpi.h>
 #include <dm/test.h>
 #include <test/ut.h>
+#include "acpi.h"
 
-#define ACPI_TEST_DEV_NAME	"ABCD"
-#define ACPI_TEST_CHILD_NAME	"EFGH"
 #define BUF_SIZE		4096
 
 /**
diff --git a/test/dm/acpi.h b/test/dm/acpi.h
index 885dff8..535db56 100644
--- a/test/dm/acpi.h
+++ b/test/dm/acpi.h
@@ -9,6 +9,9 @@
 #ifndef __TEST_DM_ACPI_H
 #define __TEST_DM_ACPI_H
 
+#define ACPI_TEST_DEV_NAME	"ABCD"
+#define ACPI_TEST_CHILD_NAME	"EFGH"
+
 /**
  * acpi_test_alloc_context_size() - Allocate an ACPI context of a given size
  *
diff --git a/test/dm/acpigen.c b/test/dm/acpigen.c
index f25be93..46792d8 100644
--- a/test/dm/acpigen.c
+++ b/test/dm/acpigen.c
@@ -916,3 +916,34 @@
 	return 0;
 }
 DM_TEST(dm_test_acpi_write_values, 0);
+
+/* Test writing a scope */
+static int dm_test_acpi_scope(struct unit_test_state *uts)
+{
+	char buf[ACPI_PATH_MAX];
+	struct acpi_ctx *ctx;
+	struct udevice *dev;
+	u8 *ptr;
+
+	ut_assertok(alloc_context(&ctx));
+	ptr = acpigen_get_current(ctx);
+
+	ut_assertok(uclass_first_device_err(UCLASS_TEST_ACPI, &dev));
+	ut_assertok(acpi_device_path(dev, buf, sizeof(buf)));
+	acpigen_write_scope(ctx, buf);
+	acpigen_pop_len(ctx);
+
+	ut_asserteq(SCOPE_OP, *ptr++);
+	ut_asserteq(13, acpi_test_get_length(ptr));
+	ptr += 3;
+	ut_asserteq(ROOT_PREFIX, *ptr++);
+	ut_asserteq(DUAL_NAME_PREFIX, *ptr++);
+	ut_asserteq_strn("_SB_" ACPI_TEST_DEV_NAME, (char *)ptr);
+	ptr += 8;
+	ut_asserteq_ptr(ptr, ctx->current);
+
+	free_context(&ctx);
+
+	return 0;
+}
+DM_TEST(dm_test_acpi_scope, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);