cfi_flash: Enable PPB protection for all AMD cmdset flash chips

Not only Spansion supports the Persistent Protection Bits (PPB) locking.
Other devices like the Micron JS28F512M29EWx also support this type
of locking/unlocking. Detection of support is done in the same way as
done for the Spansion chips - via the 0x49 CFI word.

This patch enables this PPB protection mechanism for all AMD type
(AMD commandset) chips.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Anatolij Gustschin <agust@denx.de>
Cc: Holger Brunck <holger.brunck@keymile.com>
Tested-by: Holger Brunck <holger.brunck@keymile.com>

drivers/mtd/cfi_flash.c

@@ -1511,7 +1511,7 @@ int flash_real_protect (flash_info_t * info, long sector, int prot)
 							0, ATM_CMD_UNLOCK_SECT);
 				}
 			}
-			if (manufact_match(info, AMD_MANUFACT)) {
+			if (info->legacy_unlock) {
 				int flag = disable_interrupts();
 				int lock_flag;
 
@@ -1742,12 +1742,9 @@ static int cmdset_amd_init(flash_info_t *info, struct cfi_qry *qry)
 	flash_write_cmd(info, 0, info->cfi_offset, FLASH_CMD_CFI);
 
 #ifdef CONFIG_SYS_FLASH_PROTECTION
-	if (info->ext_addr && manufact_match(info, AMD_MANUFACT)) {
-		ushort spus;
-
-		/* read sector protect/unprotect scheme */
-		spus = flash_read_uchar(info, info->ext_addr + 9);
-		if (spus == 0x8)
+	if (info->ext_addr) {
+		/* read sector protect/unprotect scheme (at 0x49) */
+		if (flash_read_uchar(info, info->ext_addr + 9) == 0x8)
 			info->legacy_unlock = 1;
 	}
 #endif
@@ -2185,7 +2182,7 @@ ulong flash_get_size (phys_addr_t base, int banknum)
 					break;
 				case CFI_CMDSET_AMD_EXTENDED:
 				case CFI_CMDSET_AMD_STANDARD:
-					if (!manufact_match(info, AMD_MANUFACT)) {
+					if (!info->legacy_unlock) {
 						/* default: not protected */
 						info->protect[sect_cnt] = 0;
 						break;