cmd: bootm: add a stage pre-load

Add a stage pre-load to the command bootm.
Right now, this stage may be used to read a
header and check the signature of the full
image.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>
diff --git a/boot/bootm.c b/boot/bootm.c
index 00c00ae..714406a 100644
--- a/boot/bootm.c
+++ b/boot/bootm.c
@@ -87,6 +87,33 @@
 	return 0;
 }
 
+static ulong bootm_data_addr(int argc, char *const argv[])
+{
+	ulong addr;
+
+	if (argc > 0)
+		addr = simple_strtoul(argv[0], NULL, 16);
+	else
+		addr = image_load_addr;
+
+	return addr;
+}
+
+static int bootm_pre_load(struct cmd_tbl *cmdtp, int flag, int argc,
+			  char *const argv[])
+{
+	ulong data_addr = bootm_data_addr(argc, argv);
+	int ret = 0;
+
+	if (CONFIG_IS_ENABLED(CMD_BOOTM_PRE_LOAD))
+		ret = image_pre_load(data_addr);
+
+	if (ret)
+		ret = CMD_RET_FAILURE;
+
+	return ret;
+}
+
 static int bootm_find_os(struct cmd_tbl *cmdtp, int flag, int argc,
 			 char *const argv[])
 {
@@ -677,6 +704,9 @@
 	if (states & BOOTM_STATE_START)
 		ret = bootm_start(cmdtp, flag, argc, argv);
 
+	if (!ret && (states & BOOTM_STATE_PRE_LOAD))
+		ret = bootm_pre_load(cmdtp, flag, argc, argv);
+
 	if (!ret && (states & BOOTM_STATE_FINDOS))
 		ret = bootm_find_os(cmdtp, flag, argc, argv);
 
@@ -866,6 +896,9 @@
 					      &fit_uname_config,
 					      &fit_uname_kernel);
 
+	if (CONFIG_IS_ENABLED(CMD_BOOTM_PRE_LOAD))
+		img_addr += image_load_offset;
+
 	bootstage_mark(BOOTSTAGE_ID_CHECK_MAGIC);
 
 	/* check image type, for FIT images get FIT kernel node */