mtd: add support for switching old SST chips into QRY mode

SST 39VF160x/39VF320x and some old SST chips need a special command
sequence to enter CFI QueRY mode [1].
This patch adds the relevant sequence to cfi_qry_mode_on().
Tested with 39VF3201.

Signed-off-by: Guillaume LECERF <glecerf@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --git a/drivers/mtd/chips/cfi_util.c b/drivers/mtd/chips/cfi_util.c
index c5a84fd..ca584d0 100755 (executable)
--- a/drivers/mtd/chips/cfi_util.c
+++ b/drivers/mtd/chips/cfi_util.c
@@ -71,6 +71,13 @@ int __xipram cfi_qry_mode_on(uint32_t base, struct map_info *map,
        cfi_send_gen_cmd(0x98, 0x555, base, map, cfi, cfi->device_type, NULL);
        if (cfi_qry_present(map, base, cfi))
                return 1;
+       /* some old SST chips, e.g. 39VF160x/39VF320x */
+       cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
+       cfi_send_gen_cmd(0xAA, 0x5555, base, map, cfi, cfi->device_type, NULL);
+       cfi_send_gen_cmd(0x55, 0x2AAA, base, map, cfi, cfi->device_type, NULL);
+       cfi_send_gen_cmd(0x98, 0x5555, base, map, cfi, cfi->device_type, NULL);
+       if (cfi_qry_present(map, base, cfi))
+               return 1;
        /* QRY not found */
        return 0;
 }