cfi_flash: Fix problems with status/id read mode

This patch adds some calls to set the flash chip in the read-status-
register- or read-id-mode before the corresponding register is
read back. This problem was detected while porting the common CFI
driver to support the Xilinx DS617 flash chips.

Signed-off-by: Stefan Roese <sr@denx.de>

drivers/mtd/cfi_flash.c

diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c
index 39c235e..643cd87 100644
--- a/drivers/mtd/cfi_flash.c
+++ b/drivers/mtd/cfi_flash.c
@@ -1426,6 +1426,11 @@
 #endif
 	};
 
+	/*
+	 * Flash needs to be in status register read mode for
+	 * flash_full_status_check() to work correctly
+	 */
+	flash_write_cmd(info, sector, 0, FLASH_CMD_READ_STATUS);
 	if ((retcode =
 	     flash_full_status_check (info, sector, info->erase_blk_tout,
 				      prot ? "protect" : "unprotect")) == 0) {
@@ -1975,6 +1980,13 @@
 				case CFI_CMDSET_INTEL_PROG_REGIONS:
 				case CFI_CMDSET_INTEL_EXTENDED:
 				case CFI_CMDSET_INTEL_STANDARD:
+					/*
+					 * Set flash to read-id mode. Otherwise
+					 * reading protected status is not
+					 * guaranteed.
+					 */
+					flash_write_cmd(info, sect_cnt, 0,
+							FLASH_CMD_READ_ID);
 					info->protect[sect_cnt] =
 						flash_isset (info, sect_cnt,
 							     FLASH_OFFSET_PROTECT,