[U-Boot] [RFC PATCH 04/11] SPL: FIT: allow loading multiple images

[Andre Przywara]

So far we were not using the FIT image format to its full potential:
The SPL FIT loader was just loading the first image from the /images
node plus one of the listed DTBs.
Now with the refactored loader code it's easy to load an arbitrary
number of images in addition to the two mentioned above.
As described in the FIT image source file format description, iterate
over all images listed at the "loadables" property in the configuration
node and load every image at its desired location.
This allows to load any kind of images:
- firmware images to execute before U-Boot proper (for instance
  ARM Trusted Firmware (ATF))
- firmware images for management processors (SCP, arisc, ...)
- firmware images for devices like WiFi controllers
- bit files for FPGAs
- additional configuration data
- kernels and/or ramdisks
The actual usage of this feature would be platform and/or board specific.

Signed-off-by: Andre Przywara <andre.przywara at arm.com>
---
 common/spl/spl_fit.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/common/spl/spl_fit.c b/common/spl/spl_fit.c
index d4149c5..18269f7 100644
--- a/common/spl/spl_fit.c
+++ b/common/spl/spl_fit.c
@@ -190,6 +190,7 @@ int spl_load_simple_fit(struct spl_image_info *spl_image,
 	struct spl_image_info image_info;
 	int node, images;
 	int base_offset, align_len = ARCH_DMA_MINALIGN - 1;
+	int index = 0;
 
 	/*
 	 * Figure out where the external images start. This is the base for the
@@ -234,6 +235,11 @@ int spl_load_simple_fit(struct spl_image_info *spl_image,
 	if (node < 0) {
 		debug("could not find firmware image, trying loadables...\n");
 		node = spl_fit_get_image_node(fit, images, "loadables", 0);
+		/*
+		 * If we pick the U-Boot image from "loadables", start at
+		 * the second image when later loading additional images.
+		 */
+		index = 1;
 	}
 	if (node < 0) {
 		debug("%s: Cannot find u-boot image node: %d\n",
@@ -259,5 +265,26 @@ int spl_load_simple_fit(struct spl_image_info *spl_image,
 	image_info.load_addr = spl_image->load_addr + spl_image->size;
 	spl_load_fit_image(info, sector, fit, base_offset, node, &image_info);
 
+	/* Now check if there are more images for us to load */
+	for (; ; index++) {
+		node = spl_fit_get_image_node(fit, images, "loadables", index);
+		if (node < 0)
+			break;
+
+		spl_load_fit_image(info, sector, fit, base_offset, node,
+				   &image_info);
+
+		/*
+		 * If the "firmware" image did not provide an entry point,
+		 * use the first valid entry point from the loadables.
+		 */
+		if (spl_image->entry_point == -1U &&
+		    image_info.entry_point != -1U)
+			spl_image->entry_point = image_info.entry_point;
+	}
+
+	if (spl_image->entry_point == -1U || spl_image->entry_point == 0)
+		spl_image->entry_point = spl_image->load_addr;
+
 	return 0;
 }
-- 
2.8.2