spl: fit: add SPL_FIT_IMAGE_TINY config to reduce code-size

A minor code-size increase from the changes for tracking the os-type
of FIT images and from infrastructure for recording the loadables into
the the loaded FDT, broke the builds for sun50i and some OMAP2+ devices.

This change adds a new config option (enabled by default for
MACH_SUN50I, MACH_SUN50I_H5 and ARCH_OMAP2PLUS) that does skips these
processing steps (bringing code size down to below the limit
again). The os-type is not evaluated, but assumed to be IH_OS_UBOOT
(i.e. taking the code-paths intended for backward-compatibility).

Note that enabling this config option precludes any useful downstream
processing, such as utilising a special calling convention for ATF or
OPTEE, based on the os-type of the loadables.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

common/spl/Kconfig

@@ -228,6 +228,22 @@ config SPL_SHA256_SUPPORT
 	  SHA256 variant is supported: SHA512 and others are not currently
 	  supported in U-Boot.
 
+config SPL_FIT_IMAGE_TINY
+	bool "Remove functionality from SPL FIT loading to reduce size"
+	depends on SPL_FIT
+	default y if MACH_SUN50I || MACH_SUN50I_H5
+	default y if ARCH_OMAP2PLUS
+	help
+	  Enable this to reduce the size of the FIT image loading code
+	  in SPL, if space for the SPL binary is very tight.
+
+	  This removes the detection of image types (which forces the
+	  first image to be treated as having a U-Boot style calling
+	  convention) and skips the recording of each loaded payload
+	  (i.e. loadable) into the FDT (modifying the loaded FDT to
+	  ensure this information is available to the next image
+	  invoked).
+
 config SPL_CPU_SUPPORT
 	bool "Support CPU drivers"
 	help

common/spl/spl_fit.c

@@ -275,8 +275,10 @@ static int spl_fit_append_fdt(struct spl_image_info *spl_image,
 
 	/* Make the load-address of the FDT available for the SPL framework */
 	spl_image->fdt_addr = (void *)image_info.load_addr;
+#if !CONFIG_IS_ENABLED(FIT_IMAGE_TINY)
 	/* Try to make space, so we can inject details on the loadables */
 	ret = fdt_shrink_to_minimum(spl_image->fdt_addr, 8192);
+#endif
 
 	return ret;
 }
@@ -284,8 +286,10 @@ static int spl_fit_append_fdt(struct spl_image_info *spl_image,
 static int spl_fit_record_loadable(const void *fit, int images, int index,
 				   void *blob, struct spl_image_info *image)
 {
+	int ret = 0;
+#if !CONFIG_IS_ENABLED(FIT_IMAGE_TINY)
 	char *name;
-	int node, ret;
+	int node;
 
 	ret = spl_fit_get_image_name(fit, images, "loadables",
 				     index, &name);
@@ -298,9 +302,19 @@ static int spl_fit_record_loadable(const void *fit, int images, int index,
 				  image->size, image->entry_point,
 				  fdt_getprop(fit, node, "type", NULL),
 				  fdt_getprop(fit, node, "os", NULL));
+#endif
 	return ret;
 }
 
+static int spl_fit_image_get_os(const void *fit, int noffset, uint8_t *os)
+{
+#if CONFIG_IS_ENABLED(FIT_IMAGE_TINY)
+	return -ENOTSUPP;
+#else
+	return fit_image_get_os(fit, noffset, os);
+#endif
+}
+
 int spl_load_simple_fit(struct spl_image_info *spl_image,
 			struct spl_load_info *info, ulong sector, void *fit)
 {
@@ -392,7 +406,7 @@ int spl_load_simple_fit(struct spl_image_info *spl_image,
 	 * For backward compatibility, we treat the first node that is
 	 * as a U-Boot image, if no OS-type has been declared.
 	 */
-	if (!fit_image_get_os(fit, node, &spl_image->os))
+	if (!spl_fit_image_get_os(fit, node, &spl_image->os))
 		debug("Image OS is %s\n", genimg_get_os_name(spl_image->os));
 #if !defined(CONFIG_SPL_OS_BOOT)
 	else
@@ -420,7 +434,7 @@ int spl_load_simple_fit(struct spl_image_info *spl_image,
 		if (ret < 0)
 			continue;
 
-		if (!fit_image_get_os(fit, node, &os_type))
+		if (!spl_fit_image_get_os(fit, node, &os_type))
 			debug("Loadable is %s\n", genimg_get_os_name(os_type));
 
 		if (os_type == IH_OS_U_BOOT) {

include/fdt_support.h

@@ -133,7 +133,6 @@ void fdt_fixup_crypto_node(void *blob, int sec_rev);
 static inline void fdt_fixup_crypto_node(void *blob, int sec_rev) {}
 #endif
 
-#if CONFIG_IS_ENABLED(LOAD_FIT)
 /**
  * Record information about a processed loadable in /fit-images (creating
  * /fit-images if necessary).
@@ -151,7 +150,6 @@ static inline void fdt_fixup_crypto_node(void *blob, int sec_rev) {}
 int fdt_record_loadable(void *blob, u32 index, const char *name,
 			uintptr_t load_addr, u32 size, uintptr_t entry_point,
 			const char *type, const char *os);
-#endif
 
 #ifdef CONFIG_PCI
 #include <pci.h>