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, 25 insertions, 0 deletions

diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 3d58c749f9f1..c998212fc680 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -151,6 +151,17 @@ enum {
         UBI_BAD_FASTMAP,
 };
 
+/*
+ * Flags for emulate_power_cut in ubi_debug_info
+ *
+ * POWER_CUT_EC_WRITE: Emulate a power cut when writing an EC header
+ * POWER_CUT_VID_WRITE: Emulate a power cut when writing a VID header
+ */
+enum {
+        POWER_CUT_EC_WRITE = 0x01,
+        POWER_CUT_VID_WRITE = 0x02,
+};
+
 /**
  * struct ubi_wl_entry - wear-leveling entry.
  * @u.rb: link in the corresponding (free/used) RB-tree
@@ -360,6 +371,10 @@ struct ubi_wl_entry;
  * @disable_bgt: disable the background task for testing purposes
  * @emulate_bitflips: emulate bit-flips for testing purposes
  * @emulate_io_failures: emulate write/erase failures for testing purposes
+ * @emulate_power_cut: emulate power cut for testing purposes
+ * @power_cut_counter: count down for writes left until emulated power cut
+ * @power_cut_min: minimum number of writes before emulating a power cut
+ * @power_cut_max: maximum number of writes until emulating a power cut
  * @dfs_dir_name: name of debugfs directory containing files of this UBI device
  * @dfs_dir: direntry object of the UBI device debugfs directory
  * @dfs_chk_gen: debugfs knob to enable UBI general extra checks
@@ -368,6 +383,9 @@ struct ubi_wl_entry;
  * @dfs_disable_bgt: debugfs knob to disable the background task
  * @dfs_emulate_bitflips: debugfs knob to emulate bit-flips
  * @dfs_emulate_io_failures: debugfs knob to emulate write/erase failures
+ * @dfs_emulate_power_cut: debugfs knob to emulate power cuts
+ * @dfs_power_cut_min: debugfs knob for minimum writes before power cut
+ * @dfs_power_cut_max: debugfs knob for maximum writes until power cut
  */
 struct ubi_debug_info {
         unsigned int chk_gen:1;
@@ -376,6 +394,10 @@ struct ubi_debug_info {
         unsigned int disable_bgt:1;
         unsigned int emulate_bitflips:1;
         unsigned int emulate_io_failures:1;
+        unsigned int emulate_power_cut:2;
+        unsigned int power_cut_counter;
+        unsigned int power_cut_min;
+        unsigned int power_cut_max;
         char dfs_dir_name[UBI_DFS_DIR_LEN + 1];
         struct dentry *dfs_dir;
         struct dentry *dfs_chk_gen;
@@ -384,6 +406,9 @@ struct ubi_debug_info {
         struct dentry *dfs_disable_bgt;
         struct dentry *dfs_emulate_bitflips;
         struct dentry *dfs_emulate_io_failures;
+        struct dentry *dfs_emulate_power_cut;
+        struct dentry *dfs_power_cut_min;
+        struct dentry *dfs_power_cut_max;
 };
 
 /**