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, 39 insertions, 0 deletions

diff --git a/lib/acpi/acpigen.c b/lib/acpi/acpigen.c
new file mode 100644
index 0000000000..a42ae26494
--- /dev/null
+++ b/lib/acpi/acpigen.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generation of ACPI (Advanced Configuration and Power Interface) tables
+ *
+ * Copyright 2019 Google LLC
+ * Mostly taken from coreboot
+ */
+
+#define LOG_CATEGORY LOGC_ACPI
+
+#include <common.h>
+#include <dm.h>
+#include <acpi/acpigen.h>
+#include <dm/acpi.h>
+
+u8 *acpigen_get_current(struct acpi_ctx *ctx)
+{
+	return ctx->current;
+}
+
+void acpigen_emit_byte(struct acpi_ctx *ctx, uint data)
+{
+	*(u8 *)ctx->current++ = data;
+}
+
+void acpigen_emit_word(struct acpi_ctx *ctx, uint data)
+{
+	acpigen_emit_byte(ctx, data & 0xff);
+	acpigen_emit_byte(ctx, (data >> 8) & 0xff);
+}
+
+void acpigen_emit_dword(struct acpi_ctx *ctx, uint data)
+{
+	/* Output the value in little-endian format */
+	acpigen_emit_byte(ctx, data & 0xff);
+	acpigen_emit_byte(ctx, (data >> 8) & 0xff);
+	acpigen_emit_byte(ctx, (data >> 16) & 0xff);
+	acpigen_emit_byte(ctx, (data >> 24) & 0xff);
+}