coreboot: common stage cache

Many chipsets were using a stage cache for reference code
or when using a relocatable ramstage. Provide a common
API for the chipsets to use while reducing code duplication.

Change-Id: Ia36efa169fe6bd8a3dbe07bf57a9729c7edbdd46
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/8625
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>
diff --git a/src/include/stage_cache.h b/src/include/stage_cache.h
new file mode 100644
index 0000000..bde5330
--- /dev/null
+++ b/src/include/stage_cache.h
@@ -0,0 +1,49 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2015 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc.
+ */
+
+#ifndef _STAGE_CACHE_H_
+#define _STAGE_CACHE_H_
+
+#include <stddef.h>
+#include <stdint.h>
+#include <program_loading.h>
+
+enum {
+	STAGE_RAMSTAGE,
+	STAGE_REFCODE,
+};
+
+/* Create an empty stage cache. */
+void stage_cache_create_empty(void);
+/* Recover existing stage cache. */
+void stage_cache_recover(void);
+/* Cache the loaded stage provided according to the parameters. */
+void stage_cache_add(int stage_id, struct prog *stage);
+/* Load the cached stage at given location returning the stage entry point. */
+void stage_cache_load_stage(int stage_id, struct prog *stage);
+/* Fill in parameters for the external stage cache, if utilized. */
+void stage_cache_external_region(void **base, size_t *size);
+
+/* Metadata associated with each stage. */
+struct stage_cache {
+	uint64_t load_addr;
+	uint64_t entry_addr;
+};
+
+#endif /* _STAGE_CACHE_H_ */