cfi-flash: Add CFG_FLASH_AUTOPROTECT_LIST

This patch adds a configurable flash auto protection list that can be used
to make U-Boot protect flash regions in flash_init().

The idea has been discussed on the u-boot mailing list starting
on Nov 18th, 2007.

Even this patch brings a new feature it is used as a bugfix for 4xx
platforms where flash_init() does not completely protect the
monitor's flash range in all situations.

U-Boot protects the flash range from CFG_MONITOR_BASE to
(CFG_MONITOR_BASE + monitor_flash_len  - 1) by default. This does not
include the reset vector at 0xfffffffc.

Example:
#define CFG_FLASH_AUTOPROTECT_LIST {{0xfff80000, 0x80000}}

This config option will auto protect the last 512k of flash that
contains the bootloader on board like APC405 and PMC405.

Signed-off-by: Matthias Fuchs <matthias.fuchs@esd-electronics.com>

drivers/mtd/cfi_flash.c

@@ -1873,6 +1873,12 @@ unsigned long flash_init (void)
 {
 	unsigned long size = 0;
 	int i;
+#if defined(CFG_FLASH_AUTOPROTECT_LIST)
+	struct apl_s {
+		ulong start;
+		ulong size;
+	} apl[] = CFG_FLASH_AUTOPROTECT_LIST;
+#endif
 
 #ifdef CFG_FLASH_PROTECTION
 	char *s = getenv("unlock");
@@ -1966,6 +1972,17 @@ unsigned long flash_init (void)
 		       CFG_ENV_ADDR_REDUND + CFG_ENV_SIZE_REDUND - 1,
 		       flash_get_info(CFG_ENV_ADDR_REDUND));
 #endif
+
+#if defined(CFG_FLASH_AUTOPROTECT_LIST)
+	for (i = 0; i < (sizeof(apl) / sizeof(struct apl_s)); i++) {
+		debug("autoprotecting from %08x to %08x\n",
+		      apl[i].start, apl[i].start + apl[i].size - 1);
+		flash_protect (FLAG_PROTECT_SET,
+			       apl[i].start,
+			       apl[i].start + apl[i].size - 1,
+			       flash_get_info(apl[i].start));
+	}
+#endif
 	return (size);
 }