UBI: power cut emulation for testing

Emulate random power cuts by switching device to ro after a number of
writes to allow simple power cut testing with nand-sim.

Maximum and minimum number of successful writes before power cut and
what kind of writes (EC header, VID header or none) to interrupt
configurable via debugfs.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Signed-off-by: Richard Weinberger <richard@nod.at>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index ed0bcb35472f..5bbd1f094f4e 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -859,6 +859,9 @@ int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
         if (err)
                 return err;
 
+        if (ubi_dbg_power_cut(ubi, POWER_CUT_EC_WRITE))
+                return -EROFS;
+
         err = ubi_io_write(ubi, ec_hdr, pnum, 0, ubi->ec_hdr_alsize);
         return err;
 }
@@ -1106,6 +1109,9 @@ int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
         if (err)
                 return err;
 
+        if (ubi_dbg_power_cut(ubi, POWER_CUT_VID_WRITE))
+                return -EROFS;
+
         p = (char *)vid_hdr - ubi->vid_hdr_shift;
         err = ubi_io_write(ubi, p, pnum, ubi->vid_hdr_aloffset,
                            ubi->vid_hdr_alsize);