sunxi_nand_spl: Be smarter about where to look for backup u-boot.bin

We know when u-boot is written to its own partition, in this case the
layout always is:

eb 0 spl
eb 1 spl-backup
eb 2 u-boot
eb 3 u-boot-backup

eb: erase-block

So if we cannot load u-boot from its primary offset we know exactly where
to look for it.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>

diff --git a/drivers/mtd/nand/sunxi_nand_spl.c b/drivers/mtd/nand/sunxi_nand_spl.c
index 5985534e5f1546073baff720db1d99b1ec0e1bcc..b0e07aa2d088a27977ddbb380d263b4a10e4a2be 100644 (file)
--- a/drivers/mtd/nand/sunxi_nand_spl.c
+++ b/drivers/mtd/nand/sunxi_nand_spl.c
@@ -356,18 +356,32 @@ static int nand_read_buffer(uint32_t offs, unsigned int size, void *dest,
 
 int nand_spl_load_image(uint32_t offs, unsigned int size, void *dest)
 {
+#if CONFIG_SYS_NAND_U_BOOT_OFFS == CONFIG_SPL_PAD_TO
+       /*
+        * u-boot-dtb.bin appended to SPL, use syndrome (like the BROM does)
+        * and try different erase block sizes to find the backup.
+        */
        const uint32_t boot_offsets[] = {
                0 * 1024 * 1024 + CONFIG_SYS_NAND_U_BOOT_OFFS,
                1 * 1024 * 1024 + CONFIG_SYS_NAND_U_BOOT_OFFS,
                2 * 1024 * 1024 + CONFIG_SYS_NAND_U_BOOT_OFFS,
                4 * 1024 * 1024 + CONFIG_SYS_NAND_U_BOOT_OFFS,
        };
-       int i, syndrome;
-
-       if (CONFIG_SYS_NAND_U_BOOT_OFFS == CONFIG_SPL_PAD_TO)
-               syndrome = 1; /* u-boot-dtb.bin appended to SPL */
-       else
-               syndrome = 0; /* u-boot-dtb.bin on its own partition */
+       const int syndrome = 1;
+#else
+       /*
+        * u-boot-dtb.bin on its own partition, do not use syndrome, u-boot
+        * partition sits after 2 eraseblocks (spl, spl-backup), look for
+        * backup u-boot 1 erase block further.
+        */
+       const uint32_t eraseblock_size = CONFIG_SYS_NAND_U_BOOT_OFFS / 2;
+       const uint32_t boot_offsets[] = {
+               CONFIG_SYS_NAND_U_BOOT_OFFS,
+               CONFIG_SYS_NAND_U_BOOT_OFFS + eraseblock_size,
+       };
+       const int syndrome = 0;
+#endif
+       int i;
 
        if (offs == CONFIG_SYS_NAND_U_BOOT_OFFS) {
                for (i = 0; i < ARRAY_SIZE(boot_offsets); i++) {