Tidy up fdt_decode_alloc_region() to make alloc separate

Move the malloc() out of fdt_decode_alloc_region() and rename it
accordingly. This makes the code somewhat cleaner and allows us
to print a sensible error message.

BUG=chromium-os:17062
TEST=build and boot on Kaen

Change-Id: I8edc8809baa42578e74c5e42cf47494b31b774e7
Reviewed-on: https://gerrit.chromium.org/gerrit/11878
Commit-Ready: Simon Glass <sjg@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>

3 files changed, 28 insertions, 16 deletions

diff --git a/common/fdt_decode.c b/common/fdt_decode.c
index b6beebda69..dab673a02c 100644
--- a/common/fdt_decode.c
+++ b/common/fdt_decode.c
@@ -23,7 +23,6 @@
 
 #include <fdt_decode.h>
 #include <libfdt.h>
-#include <malloc.h>
 #include <serial.h>
 
 /* we need a generic GPIO interface here */
@@ -703,22 +702,19 @@ int fdt_decode_nand(const void *blob, int node, struct fdt_nand *config)
 	return fdt_decode_gpio(blob, node, "wp-gpio", &config->wp_gpio);
 }
 
-void *fdt_decode_alloc_region(const void *blob, int node,
-		const char *prop_name, size_t *size)
+int fdt_decode_region(const void *blob, int node,
+		const char *prop_name, void **ptrp, size_t *size)
 {
 	const addr_t *cell;
-	void *ptr;
 	int len;
 
 	debug("%s: %s\n", __func__, prop_name);
 	cell = fdt_getprop(blob, node, prop_name, &len);
 	if (!cell || (len != sizeof(addr_t) * 2))
-		return NULL;
+		return -1;
 
-	ptr = (void *)addr_to_cpu(*cell);
+	*ptrp = (void *)addr_to_cpu(*cell);
 	*size = size_to_cpu(cell[1]);
 	debug("%s: size=%zx\n", __func__, *size);
-	if (!ptr)
-		ptr = malloc(*size);
-	return ptr;
+	return 0;
 }
diff --git a/include/fdt_decode.h b/include/fdt_decode.h
index e787b902bf..6087c21861 100644
--- a/include/fdt_decode.h
+++ b/include/fdt_decode.h
@@ -600,8 +600,7 @@ int fdt_decode_nand(const void *blob, int node, struct fdt_nand *config);
 
 /**
  * Look up a property in a node which contains a memory region address and
- * size. Then return a pointer to this address. if the address is zero, it is
- * allocated with malloc() instead.
+ * size. Then return a pointer to this address.
  *
  * The property must hold one address with a length. This is only tested on
  * 32-bit machines.
@@ -609,8 +608,9 @@ int fdt_decode_nand(const void *blob, int node, struct fdt_nand *config);
  * @param blob		FDT blob
  * @param node		node to examine
  * @param prop_name	name of property to find
+ * @param ptrp		returns pointer to region, or NULL if no address
  * @param size		returns size of region
- * @return pointer to region, or NULL if property not found/malloc failed
+ * @return 0 if ok, -1 on error (propery not found)
  */
-void *fdt_decode_alloc_region(const void *blob, int node,
-		const char *prop_name, size_t *size);
+int fdt_decode_region(const void *blob, int node,
+		const char *prop_name, void **ptrp, size_t *size);
diff --git a/lib/chromeos/fdt_decode.c b/lib/chromeos/fdt_decode.c
index fbc44a320e..3be76643d2 100644
--- a/lib/chromeos/fdt_decode.c
+++ b/lib/chromeos/fdt_decode.c
@@ -15,6 +15,7 @@
 #include <chromeos/fmap.h>
 #include <fdt_decode.h>
 #include <linux/string.h>
+#include <malloc.h>
 
 #define PREFIX "chromeos/fdt_decode: "
 
@@ -161,9 +162,24 @@ void *fdt_decode_chromeos_alloc_region(const void *blob,
 		const char *prop_name, size_t *size)
 {
 	int node = fdt_path_offset(blob, "/chromeos-config");
+	void *ptr;
 
-	if (node < 0)
+	if (node < 0) {
+		VBDEBUG(PREFIX "failed to find /chromeos-config in fdt'\n");
 		return NULL;
+	}
 
-	return fdt_decode_alloc_region(blob, node, prop_name, size);
+	if (fdt_decode_region(blob, node, prop_name, &ptr, size)) {
+		VBDEBUG(PREFIX "failed to find %s in /chromeos-config'\n",
+			prop_name);
+		return NULL;
+	}
+
+	if (!ptr)
+		ptr = malloc(*size);
+	if (!ptr) {
+		VBDEBUG(PREFIX "failed to alloc %d bytes for %s'\n",
+			*size, prop_name);
+	}
+	return ptr;
 }