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>

src/vendorcode/google/chromeos/chromeos.c

@@ -82,7 +82,9 @@ int recovery_mode_enabled(void)
 }
 
 #if CONFIG_VBOOT_VERIFY_FIRMWARE
-void *vboot_get_payload(size_t *len)
+#include <payload_loader.h>
+
+static void *vboot_get_payload(size_t *len)
 {
 	struct vboot_handoff *vboot_handoff;
 	struct firmware_component *fwc;
@@ -109,6 +111,27 @@ void *vboot_get_payload(size_t *len)
 	return (void *)fwc->address;
 }
 
+static int vboot_locate_payload(struct payload *payload)
+{
+	void *buffer;
+	size_t size;
+
+	buffer = vboot_get_payload(&size);
+
+	if (buffer == NULL)
+		return -1;
+
+	payload->backing_store.data = buffer;
+	payload->backing_store.size = size;
+
+	return 0;
+}
+
+const struct payload_loader_ops vboot_payload_loader = {
+	.name = "VBOOT",
+	.locate = vboot_locate_payload,
+};
+
 int vboot_get_handoff_info(void **addr, uint32_t *size)
 {
 	struct vboot_handoff *vboot_handoff;

src/vendorcode/google/chromeos/chromeos.h

@@ -47,7 +47,6 @@ int recovery_mode_enabled(void);
 void init_chromeos(int bootmode);
 
 #if CONFIG_VBOOT_VERIFY_FIRMWARE
-void *vboot_get_payload(size_t *len);
 /* Returns 0 on success < 0 on error. */
 int vboot_get_handoff_info(void **addr, uint32_t *size);
 #endif