spl: net: Add FIT image support over network boot

FIT support in the net boot case is much like the RAM boot case in that
we load our image to "load_addr" and pass a dummy read function into
"spl_load_simple_fit()". As the load address is no longer hard-coded to
the final execution address, legacy image loading will require load_addr
to be set correctly in the image header.

Signed-off-by: Andrew F. Davis <afd@ti.com>

common/spl/spl_net.c

@@ -11,19 +11,29 @@
 #include <errno.h>
 #include <spl.h>
 #include <net.h>
+#include <libfdt.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
 #if defined(CONFIG_SPL_ETH_SUPPORT) || defined(CONFIG_SPL_USBETH_SUPPORT)
+static ulong spl_net_load_read(struct spl_load_info *load, ulong sector,
+			       ulong count, void *buf)
+{
+	debug("%s: sector %lx, count %lx, buf %lx\n",
+	      __func__, sector, count, (ulong)buf);
+	memcpy(buf, (void *)(load_addr + sector), count);
+	return count;
+}
+
 static int spl_net_load_image(struct spl_image_info *spl_image,
 			      struct spl_boot_device *bootdev)
 {
+	struct image_header *header = (struct image_header *)load_addr;
 	int rv;
 
 	env_init();
 	env_relocate();
 	setenv("autoload", "yes");
-	load_addr = CONFIG_SYS_TEXT_BASE - sizeof(struct image_header);
 	rv = eth_initialize();
 	if (rv == 0) {
 		printf("No Ethernet devices found\n");
@@ -36,8 +46,26 @@ static int spl_net_load_image(struct spl_image_info *spl_image,
 		printf("Problem booting with BOOTP\n");
 		return rv;
 	}
-	return spl_parse_image_header(spl_image,
-				      (struct image_header *)load_addr);
+
+	if (IS_ENABLED(CONFIG_SPL_LOAD_FIT) &&
+	    image_get_magic(header) == FDT_MAGIC) {
+		struct spl_load_info load;
+
+		debug("Found FIT\n");
+		load.bl_len = 1;
+		load.read = spl_net_load_read;
+		rv = spl_load_simple_fit(spl_image, &load, 0, header);
+	} else {
+		debug("Legacy image\n");
+
+		rv = spl_parse_image_header(spl_image, header);
+		if (rv)
+			return rv;
+
+		memcpy((void *)spl_image->load_addr, header, spl_image->size);
+	}
+
+	return rv;
 }
 #endif