image: Add FIT image loadable section custom processing

To help automate the loading of custom image types we add the ability
to define custom handlers for the loadable section types. When we find
a compatible type while loading a "loadable" image from a FIT image we
run its associated handlers to perform any additional steps needed for
loading this image.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/image.c b/common/image.c
index 7604494..2aac90d 100644
--- a/common/image.c
+++ b/common/image.c
@@ -1389,6 +1389,23 @@
 }
 #endif
 
+static void fit_loadable_process(uint8_t img_type,
+				 ulong img_data,
+				 ulong img_len)
+{
+	int i;
+	const unsigned int count =
+			ll_entry_count(struct fit_loadable_tbl, fit_loadable);
+	struct fit_loadable_tbl *fit_loadable_handler =
+			ll_entry_start(struct fit_loadable_tbl, fit_loadable);
+	/* For each loadable handler */
+	for (i = 0; i < count; i++, fit_loadable_handler++)
+		/* matching this type */
+		if (fit_loadable_handler->type == img_type)
+			/* call that handler with this image data */
+			fit_loadable_handler->handler(img_data, img_len);
+}
+
 int boot_get_loadable(int argc, char * const argv[], bootm_headers_t *images,
 		uint8_t arch, const ulong *ld_start, ulong * const ld_len)
 {
@@ -1407,6 +1424,7 @@
 	int conf_noffset;
 	int fit_img_result;
 	const char *uname;
+	uint8_t img_type;
 
 	/* Check to see if the images struct has a FIT configuration */
 	if (!genimg_has_config(images)) {
@@ -1447,6 +1465,21 @@
 				/* Something went wrong! */
 				return fit_img_result;
 			}
+
+			fit_img_result = fit_image_get_node(buf, uname);
+			if (fit_img_result < 0) {
+				/* Something went wrong! */
+				return fit_img_result;
+			}
+			fit_img_result = fit_image_get_type(buf,
+							    fit_img_result,
+							    &img_type);
+			if (fit_img_result < 0) {
+				/* Something went wrong! */
+				return fit_img_result;
+			}
+
+			fit_loadable_process(img_type, img_data, img_len);
 		}
 		break;
 	default:
diff --git a/doc/uImage.FIT/source_file_format.txt b/doc/uImage.FIT/source_file_format.txt
index 91aa89a..afff301 100644
--- a/doc/uImage.FIT/source_file_format.txt
+++ b/doc/uImage.FIT/source_file_format.txt
@@ -256,7 +256,9 @@
     (component image node of a "fpga type").
   - loadables : Unit name containing a list of additional binaries to be
     loaded at their given locations.  "loadables" is a comma-separated list
-    of strings. U-Boot will load each binary at its given start-address.
+    of strings. U-Boot will load each binary at its given start-address and
+    may optionaly invoke additional post-processing steps on this binary based
+    on its component image node type.
 
 The FDT blob is required to properly boot FDT based kernel, so the minimal
 configuration for 2.6 FDT kernel is (kernel, fdt) pair.
diff --git a/include/image.h b/include/image.h
index 8131595..b96b8eb 100644
--- a/include/image.h
+++ b/include/image.h
@@ -1271,4 +1271,34 @@
 void board_fit_image_post_process(void **p_image, size_t *p_size);
 #endif /* CONFIG_SPL_FIT_IMAGE_POST_PROCESS */
 
+/**
+ * Mapping of image types to function handlers to be invoked on the associated
+ * loaded images
+ *
+ * @type: Type of image, I.E. IH_TYPE_*
+ * @handler: Function to call on loaded image
+ */
+struct fit_loadable_tbl {
+	int type;
+	/**
+	 * handler() - Process a loaded image
+	 *
+	 * @data: Pointer to start of loaded image data
+	 * @size: Size of loaded image data
+	 */
+	void (*handler)(ulong data, size_t size);
+};
+
+/*
+ * Define a FIT loadable image type handler
+ *
+ * _type is a valid uimage_type ID as defined in the "Image Type" enum above
+ * _handler is the handler function to call after this image type is loaded
+ */
+#define U_BOOT_FIT_LOADABLE_HANDLER(_type, _handler) \
+	ll_entry_declare(struct fit_loadable_tbl, _function, fit_loadable) = { \
+		.type = _type, \
+		.handler = _handler, \
+	}
+
 #endif	/* __IMAGE_H__ */