As the reset vector is located at 0xfffffffc, all flash sectors from the beginning of the U-Boot binary to 0xffffffff must be protected. On the TQM8548-AG having small sectors at the end of the flash it happened that the last two sector were not protected and an "erase all" left an un-bootable system behind:
Bank # 2: CFI conformant FLASH (32 x 16) Size: 32 MB in 270 Sectors AMD Standard command set, Manufacturer ID: 0xEC, Device ID: 0x257E Erase timeout: 8192 ms, write timeout: 1 ms
FFFA0000 E RO FFFC0000 RO FFFE0000 RO FFFE4000 RO FFFE8000 RO FFFEC000 RO FFFF0000 RO FFFF4000 RO FFFF8000 E FFFFC000
The same bug seems to be in drivers/mtd/cfi_flash.c:flash_init() and many board BSPs as well.
Signed-off-by: Wolfgang Grandegger wg@grandegger.com --- board/tqc/tqm85xx/tqm85xx.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
Index: u-boot/board/tqc/tqm85xx/tqm85xx.c =================================================================== --- u-boot.orig/board/tqc/tqm85xx/tqm85xx.c +++ u-boot/board/tqc/tqm85xx/tqm85xx.c @@ -315,8 +315,7 @@ int misc_init_r (void)
/* Monitor protection ON by default */ flash_protect (FLAG_PROTECT_SET, - CONFIG_SYS_MONITOR_BASE, - CONFIG_SYS_MONITOR_BASE + monitor_flash_len - 1, + CONFIG_SYS_MONITOR_BASE, 0xffffffff, &flash_info[CONFIG_SYS_MAX_FLASH_BANKS - 1]);
/* Environment protection ON by default */