[U-Boot] [PATCH v5 04/15] spl: fit: allocate a temporary buffer to load the overlays

[Jean-Jacques Hiblot]

If the node describing an overlay does not specify a load address, it will
be loaded at the address previously used.
Fixing it by allocating a temporary buffer that will be used as a
default load address. By default, the size of the buffer is 64kB which
should be plenty for most use cases.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot at ti.com>

---

Changes in v5:
- Do not allocate the buffer if not needed (no overlay).
- Add a Kconfig option for the buffer size

Changes in v4:
- make sure that the temp buffer is freed in all cases

Changes in v3: None
Changes in v2: None

 Kconfig              |  9 +++++++++
 common/spl/spl_fit.c | 34 +++++++++++++++++++++++++++++-----
 2 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/Kconfig b/Kconfig
index 825f096807..a41d33de13 100644
--- a/Kconfig
+++ b/Kconfig
@@ -437,6 +437,15 @@ config SPL_LOAD_FIT_APPLY_OVERLAY
 	  also load device-tree overlays from the FIT image an apply them
 	  over the device tree.
 
+config SPL_LOAD_FIT_APPLY_OVERLAY_BUF_SZ
+	depends on SPL_LOAD_FIT_APPLY_OVERLAY
+	default 0x10000
+	hex "size of temporary buffer used to load the overlays"
+	help
+	  The size of the area where the overlays will be loaded and
+	  uncompress. Must be at least as large as biggest overlay
+	  (uncompressed)
+
 config SPL_LOAD_FIT_FULL
 	bool "Enable SPL loading U-Boot as a FIT (full fitImage features)"
 	select SPL_FIT
diff --git a/common/spl/spl_fit.c b/common/spl/spl_fit.c
index 95b45aafa2..4fdc10c9e2 100644
--- a/common/spl/spl_fit.c
+++ b/common/spl/spl_fit.c
@@ -9,11 +9,16 @@
 #include <fpga.h>
 #include <gzip.h>
 #include <image.h>
-#include <linux/libfdt.h>
+#include <malloc.h>
 #include <spl.h>
+#include <linux/libfdt.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
+#ifndef CONFIG_SPL_LOAD_FIT_APPLY_OVERLAY_BUF_SZ
+#define CONFIG_SPL_LOAD_FIT_APPLY_OVERLAY_BUF_SZ (64 * 1024)
+#endif
+
 #ifndef CONFIG_SYS_BOOTM_LEN
 #define CONFIG_SYS_BOOTM_LEN	(64 << 20)
 #endif
@@ -314,33 +319,52 @@ static int spl_fit_append_fdt(struct spl_image_info *spl_image,
 	spl_image->fdt_addr = (void *)image_info.load_addr;
 #if !CONFIG_IS_ENABLED(FIT_IMAGE_TINY)
 	if (CONFIG_IS_ENABLED(LOAD_FIT_APPLY_OVERLAY)) {
+		void *tmpbuffer = NULL;
+
 		for (; ; index++) {
 			node = spl_fit_get_image_node(fit, images, FIT_FDT_PROP,
 						      index);
 			if (node < 0) {
 				debug("%s: No additional FDT node\n", __func__);
-				return 0;
+				break;
 			}
 
+			if (!tmpbuffer) {
+				/*
+				 * allocate memory to store the DT overlay
+				 * before it is applied. It may not be used
+				 * depending on how the overlay is stored, so
+				 * don't fail yet if the allocation failed.
+				 */
+				tmpbuffer = malloc(CONFIG_SPL_LOAD_FIT_APPLY_OVERLAY_BUF_SZ);
+				if (!tmpbuffer)
+					debug("%s: unable to allocate space for overlays\n",
+					      __func__);
+			}
+			image_info.load_addr = (ulong)tmpbuffer;
 			ret = spl_load_fit_image(info, sector, fit, base_offset,
 						 node, &image_info);
 			if (ret < 0)
-				return ret;
+				break;
 
 			/* Make room in FDT for changes from the overlay */
 			ret = fdt_increase_size(spl_image->fdt_addr,
 						image_info.size);
 			if (ret < 0)
-				return ret;
+				break;
 
 			ret = fdt_overlay_apply_verbose(spl_image->fdt_addr,
 							(void *)image_info.load_addr);
 			if (ret)
-				return ret;
+				break;
 
 			debug("%s: DT overlay %s applied\n", __func__,
 			      fit_get_name(fit, node, NULL));
 		}
+		if (tmpbuffer)
+			free(tmpbuffer);
+		if (ret)
+			return ret;
 	}
 	/* Try to make space, so we can inject details on the loadables */
 	ret = fdt_shrink_to_minimum(spl_image->fdt_addr, 8192);
-- 
2.17.1