arm/cpu/start.c: Distil some common code in __start().

Both barebox_boarddata and barebox_boot_dtb perform essentially the
same function -- hold a pointer to a chunk of private data. Since only
one variable is ever used at any given time we may as well merge those
two variable into one. This also allows us to share more code between
two boot paths (board data vs. device tree)

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 36 insertions, 24 deletions

diff --git a/arch/arm/cpu/start.c b/arch/arm/cpu/start.c
index 8e5097b560..e6f5e186bd 100644
--- a/arch/arm/cpu/start.c
+++ b/arch/arm/cpu/start.c
@@ -34,23 +34,34 @@
 unsigned long arm_stack_top;
 static void *barebox_boarddata;
 
-u32 barebox_arm_machine(void)
+static bool blob_is_fdt(const void *blob)
 {
-	struct barebox_arm_boarddata *bd;
-
-	if (!barebox_boarddata)
-		return 0;
+	return get_unaligned_be32(blob) == FDT_MAGIC;
+}
 
-	bd = barebox_boarddata;
+static bool blob_is_arm_boarddata(const void *blob)
+{
+	const struct barebox_arm_boarddata *bd = blob;
 
-	return bd->machine;
+	return bd->magic == BAREBOX_ARM_BOARDDATA_MAGIC;
 }
 
-static void *barebox_boot_dtb;
+u32 barebox_arm_machine(void)
+{
+	if (barebox_boarddata && blob_is_arm_boarddata(barebox_boarddata)) {
+		const struct barebox_arm_boarddata *bd = barebox_boarddata;
+		return bd->machine;
+	} else {
+		return 0;
+	}
+}
 
 void *barebox_arm_boot_dtb(void)
 {
-	return barebox_boot_dtb;
+	if (barebox_boarddata && blob_is_fdt(barebox_boarddata))
+		return barebox_boarddata;
+	else
+		return NULL;
 }
 
 static noinline __noreturn void __start(unsigned long membase,
@@ -70,7 +81,6 @@ static noinline __noreturn void __start(unsigned long membase,
 
 	pr_debug("memory at 0x%08lx, size 0x%08lx\n", membase, memsize);
 
-	barebox_boarddata = boarddata;
 	arm_stack_top = endmem;
 	endmem -= STACK_SIZE; /* Stack */
 
@@ -89,21 +99,23 @@ static noinline __noreturn void __start(unsigned long membase,
 	}
 
 	if (boarddata) {
-		if (get_unaligned_be32(boarddata) == FDT_MAGIC) {
-			uint32_t totalsize = get_unaligned_be32(boarddata + 4);
+		uint32_t totalsize = 0;
+		const char *name;
+
+		if (blob_is_fdt(boarddata)) {
+			totalsize = get_unaligned_be32(boarddata + 4);
+			name = "DTB";
+		} else if (blob_is_arm_boarddata(boarddata)) {
+			totalsize = sizeof(struct barebox_arm_boarddata);
+			name = "machine type";
+		}
+
+		if (totalsize) {
 			endmem -= ALIGN(totalsize, 64);
-			barebox_boot_dtb = (void *)endmem;
-			pr_debug("found DTB in boarddata, copying to 0x%p\n",
-					barebox_boot_dtb);
-			memcpy(barebox_boot_dtb, boarddata, totalsize);
-		} else if (((struct barebox_arm_boarddata *)boarddata)->magic ==
-				BAREBOX_ARM_BOARDDATA_MAGIC) {
-			endmem -= ALIGN(sizeof(struct barebox_arm_boarddata), 64);
-			barebox_boarddata = (void *)endmem;
-			pr_debug("found machine type in boarddata, copying to 0x%p\n",
-					barebox_boarddata);
-			memcpy(barebox_boarddata, boarddata,
-					sizeof(struct barebox_arm_boarddata));
+			pr_debug("found %s in boarddata, copying to 0x%lu\n",
+				 name, endmem);
+			barebox_boarddata = memcpy((void *)endmem,
+						      boarddata, totalsize);
 		}
 	}