coreboot: unify infrastructure for loading payloads

A payload can be loaded either from a vboot region or from cbfs.
Provide a common place for choosing where the payload is loaded
from. Additionally, place the logic in the 'loaders' directory
similarly to the ramstage loader infrastructure.

Change-Id: I6b0034ea5ebd04a3d058151819ac77a126a6bfe2
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/5296
Tested-by: build bot (Jenkins)
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
diff --git a/src/include/payload_loader.h b/src/include/payload_loader.h
new file mode 100644
index 0000000..b8bfc0d
--- /dev/null
+++ b/src/include/payload_loader.h
@@ -0,0 +1,61 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2014 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#ifndef PAYLOAD_LOADER_H
+#define PAYLOAD_LOADER_H
+
+#include <stdint.h>
+#include <stddef.h>
+
+struct payload_backing_store {
+	void *data;
+	size_t size;
+};
+
+struct payload {
+	const char *name;
+	struct payload_backing_store backing_store;
+	void *entry;
+};
+
+/*
+ * Load payload into memory and return pointer to payload structure. Returns
+ * NULL on error.
+ */
+struct payload *payload_load(void);
+
+/* Run the loaded payload. */
+void payload_run(const struct payload *payload);
+
+/* Payload loading operations. */
+struct payload_loader_ops {
+	const char *name;
+	/*
+	 * Fill in payload_backing_store structure.  Return 0 on success, < 0
+	 * on failure.
+	 */
+	int (*locate)(struct payload *payload);
+};
+
+/* Defined in src/lib/selfboot.c */
+struct lb_memory;
+struct cbfs_payload;
+void *selfload(struct lb_memory *mem, struct cbfs_payload *payload);
+void selfboot(void *entry);
+
+#endif  /* PAYLOAD_LOADER_H */