[U-Boot] [RFC PATCH 2/3] sunxi: board.c: refactor SPL header checks

[Andre Przywara]

So far we have two users which want to look at the SPL header. We will
get more in the future.
Refactor the existing SPL header checks into a common function, to
simplify reusing the code.
Now that this is easy, add proper version checks to the DT name parsing.

Signed-off-by: Andre Przywara <andre.przywara at arm.com>
---
 board/sunxi/board.c | 41 ++++++++++++++++++++++++++++++-----------
 1 file changed, 30 insertions(+), 11 deletions(-)

diff --git a/board/sunxi/board.c b/board/sunxi/board.c
index a105d0a5ab..0bb7b023ed 100644
--- a/board/sunxi/board.c
+++ b/board/sunxi/board.c
@@ -253,6 +253,30 @@ int board_init(void)
 	return soft_i2c_board_init();
 }
 
+/*
+ * On older SoCs the SPL is actually at address zero, so using NULL as
+ * an error value does not work.
+ */
+#define INVALID_SPL_HEADER ((void *)~0UL)
+
+static struct boot_file_head * get_spl_header(uint8_t req_version)
+{
+	struct boot_file_head *spl = (void *)(ulong)SPL_ADDR;
+	uint8_t spl_header_version = spl->spl_signature[3];
+
+	/* Is there really the SPL header (still) there? */
+	if (memcmp(spl->spl_signature, SPL_SIGNATURE, 3) != 0)
+		return INVALID_SPL_HEADER;
+
+	if (spl_header_version < req_version) {
+		printf("sunxi SPL version mismatch: expected %u, got %u\n",
+		       req_version, spl_header_version);
+		return INVALID_SPL_HEADER;
+	}
+
+	return spl;
+}
+
 int dram_init(void)
 {
 	gd->ram_size = get_ram_size((long *)PHYS_SDRAM_0, PHYS_SDRAM_0_SIZE);
@@ -626,16 +650,11 @@ void get_board_serial(struct tag_serialnr *serialnr)
  */
 static void parse_spl_header(const uint32_t spl_addr)
 {
-	struct boot_file_head *spl = (void *)(ulong)spl_addr;
-	if (memcmp(spl->spl_signature, SPL_SIGNATURE, 3) != 0)
-		return; /* signature mismatch, no usable header */
+	struct boot_file_head *spl = get_spl_header(SPL_ENV_HEADER_VERSION);
 
-	uint8_t spl_header_version = spl->spl_signature[3];
-	if (spl_header_version < SPL_ENV_HEADER_VERSION) {
-		printf("sunxi SPL version mismatch: expected %u, got %u\n",
-		       SPL_ENV_HEADER_VERSION, spl_header_version);
+	if (spl == INVALID_SPL_HEADER)
 		return;
-	}
+
 	if (!spl->fel_script_address)
 		return;
 
@@ -777,11 +796,11 @@ int ft_board_setup(void *blob, bd_t *bd)
 #ifdef CONFIG_SPL_LOAD_FIT
 int board_fit_config_name_match(const char *name)
 {
-	struct boot_file_head *spl = (void *)(ulong)SPL_ADDR;
-	const char *cmp_str = (void *)(ulong)SPL_ADDR;
+	struct boot_file_head *spl = get_spl_header(SPL_DT_HEADER_VERSION);
+	const char *cmp_str = (const char *)spl;
 
 	/* Check if there is a DT name stored in the SPL header and use that. */
-	if (spl->dt_name_offset) {
+	if (spl != INVALID_SPL_HEADER && spl->dt_name_offset) {
 		cmp_str += spl->dt_name_offset;
 	} else {
 #ifdef CONFIG_DEFAULT_DEVICE_TREE
-- 
2.14.1