acpi: Support generation of ACPI code

Add a new file to handle generating ACPI code programatically. This is
used when information must be dynamically added to the tables, e.g. the
SSDT.

Initial support is just for writing simple values. Also add a 'base' value
so that the table can be freed. This likely doesn't happen in normal code,
but is nice to do in tests.

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>

1 files changed, 49 insertions, 0 deletions

diff --git a/include/acpi/acpigen.h b/include/acpi/acpigen.h
new file mode 100644
index 00000000000..8809cdb4e12
--- /dev/null
+++ b/include/acpi/acpigen.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Core ACPI (Advanced Configuration and Power Interface) support
+ *
+ * Copyright 2019 Google LLC
+ *
+ * Modified from coreboot file acpigen.h
+ */
+
+#ifndef __ACPI_ACPIGEN_H
+#define __ACPI_ACPIGEN_H
+
+#include <linux/types.h>
+
+struct acpi_ctx;
+
+/**
+ * acpigen_get_current() - Get the current ACPI code output pointer
+ *
+ * @ctx: ACPI context pointer
+ * @return output pointer
+ */
+u8 *acpigen_get_current(struct acpi_ctx *ctx);
+
+/**
+ * acpigen_emit_byte() - Emit a byte to the ACPI code
+ *
+ * @ctx: ACPI context pointer
+ * @data: Value to output
+ */
+void acpigen_emit_byte(struct acpi_ctx *ctx, uint data);
+
+/**
+ * acpigen_emit_word() - Emit a 16-bit word to the ACPI code
+ *
+ * @ctx: ACPI context pointer
+ * @data: Value to output
+ */
+void acpigen_emit_word(struct acpi_ctx *ctx, uint data);
+
+/**
+ * acpigen_emit_dword() - Emit a 32-bit 'double word' to the ACPI code
+ *
+ * @ctx: ACPI context pointer
+ * @data: Value to output
+ */
+void acpigen_emit_dword(struct acpi_ctx *ctx, uint data);
+
+#endif