spl: fit: Load devicetree when a Linux payload is found

When a FIT config specifies a devicetree, we should load it, no
questions asked. In the case of the "simple" FIT loading path, a
difficulty arises in selecting the load address of the FDT.

The default FDT location is right after the "kernel" or "firmware"
image. However, if that is an OP-TEE image, then the FDT may end up in
secure DRAM, and not be accessible to normal world kernels.

Although the best solution is to be more careful about the FDT
address, a viable workaround is to only append the FDT after a u-boot
or Linux image. This is identical to the previous logic, except that
FDT loading is extended to IH_OS_LINUX images.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
diff --git a/common/spl/spl_fit.c b/common/spl/spl_fit.c
index 50670bf..75c8ff0 100644
--- a/common/spl/spl_fit.c
+++ b/common/spl/spl_fit.c
@@ -336,6 +336,18 @@
 	return 0;
 }
 
+static bool os_takes_devicetree(uint8_t os)
+{
+	switch (os) {
+	case IH_OS_U_BOOT:
+		return true;
+	case IH_OS_LINUX:
+		return IS_ENABLED(CONFIG_SPL_OS_BOOT);
+	default:
+		return false;
+	}
+}
+
 static int spl_fit_append_fdt(struct spl_image_info *spl_image,
 			      struct spl_load_info *info, ulong sector,
 			      const struct spl_fit_info *ctx)
@@ -662,9 +674,9 @@
 	 * Booting a next-stage U-Boot may require us to append the FDT.
 	 * We allow this to fail, as the U-Boot image might embed its FDT.
 	 */
-	if (spl_image->os == IH_OS_U_BOOT) {
+	if (os_takes_devicetree(spl_image->os)) {
 		ret = spl_fit_append_fdt(spl_image, info, sector, &ctx);
-		if (!IS_ENABLED(CONFIG_OF_EMBED) && ret < 0)
+		if (ret < 0 && spl_image->os != IH_OS_U_BOOT)
 			return ret;
 	}
 
@@ -695,7 +707,7 @@
 		if (!spl_fit_image_get_os(ctx.fit, node, &os_type))
 			debug("Loadable is %s\n", genimg_get_os_name(os_type));
 
-		if (os_type == IH_OS_U_BOOT) {
+		if (os_takes_devicetree(os_type)) {
 			spl_fit_append_fdt(&image_info, info, sector, &ctx);
 			spl_image->fdt_addr = image_info.fdt_addr;
 		}