--- zzzz-none-000/linux-3.10.107/drivers/mtd/ubi/debug.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/drivers/mtd/ubi/debug.c	2021-02-04 17:41:59.000000000 +0000
@@ -43,12 +43,12 @@
 		return;
 	err = mtd_read(ubi->mtd, addr, len, &read, buf);
 	if (err && err != -EUCLEAN) {
-		ubi_err("error %d while reading %d bytes from PEB %d:%d, read %zd bytes",
+		ubi_err(ubi, "err %d while reading %d bytes from PEB %d:%d, read %zd bytes",
 			err, len, pnum, offset, read);
 		goto out;
 	}
 
-	ubi_msg("dumping %d bytes of data from PEB %d, offset %d",
+	ubi_msg(ubi, "dumping %d bytes of data from PEB %d, offset %d",
 		len, pnum, offset);
 	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1, buf, len, 1);
 out:
@@ -236,10 +236,10 @@
 
 	dfs_rootdir = debugfs_create_dir("ubi", NULL);
 	if (IS_ERR_OR_NULL(dfs_rootdir)) {
-		int err = dfs_rootdir ? -ENODEV : PTR_ERR(dfs_rootdir);
+		int err = dfs_rootdir ? PTR_ERR(dfs_rootdir) : -ENODEV;
 
-		ubi_err("cannot create \"ubi\" debugfs directory, error %d\n",
-			err);
+		pr_err("UBI error: cannot create \"ubi\" debugfs directory, error %d\n",
+		       err);
 		return err;
 	}
 
@@ -263,7 +263,7 @@
 	struct dentry *dent = file->f_path.dentry;
 	struct ubi_device *ubi;
 	struct ubi_debug_info *d;
-	char buf[3];
+	char buf[8];
 	int val;
 
 	ubi = ubi_get_device(ubi_num);
@@ -275,12 +275,30 @@
 		val = d->chk_gen;
 	else if (dent == d->dfs_chk_io)
 		val = d->chk_io;
+	else if (dent == d->dfs_chk_fastmap)
+		val = d->chk_fastmap;
 	else if (dent == d->dfs_disable_bgt)
 		val = d->disable_bgt;
 	else if (dent == d->dfs_emulate_bitflips)
 		val = d->emulate_bitflips;
 	else if (dent == d->dfs_emulate_io_failures)
 		val = d->emulate_io_failures;
+	else if (dent == d->dfs_emulate_power_cut) {
+		snprintf(buf, sizeof(buf), "%u\n", d->emulate_power_cut);
+		count = simple_read_from_buffer(user_buf, count, ppos,
+						buf, strlen(buf));
+		goto out;
+	} else if (dent == d->dfs_power_cut_min) {
+		snprintf(buf, sizeof(buf), "%u\n", d->power_cut_min);
+		count = simple_read_from_buffer(user_buf, count, ppos,
+						buf, strlen(buf));
+		goto out;
+	} else if (dent == d->dfs_power_cut_max) {
+		snprintf(buf, sizeof(buf), "%u\n", d->power_cut_max);
+		count = simple_read_from_buffer(user_buf, count, ppos,
+						buf, strlen(buf));
+		goto out;
+	}
 	else {
 		count = -EINVAL;
 		goto out;
@@ -309,7 +327,7 @@
 	struct ubi_device *ubi;
 	struct ubi_debug_info *d;
 	size_t buf_size;
-	char buf[8];
+	char buf[8] = {0};
 	int val;
 
 	ubi = ubi_get_device(ubi_num);
@@ -323,6 +341,21 @@
 		goto out;
 	}
 
+	if (dent == d->dfs_power_cut_min) {
+		if (kstrtouint(buf, 0, &d->power_cut_min) != 0)
+			count = -EINVAL;
+		goto out;
+	} else if (dent == d->dfs_power_cut_max) {
+		if (kstrtouint(buf, 0, &d->power_cut_max) != 0)
+			count = -EINVAL;
+		goto out;
+	} else if (dent == d->dfs_emulate_power_cut) {
+		if (kstrtoint(buf, 0, &val) != 0)
+			count = -EINVAL;
+		d->emulate_power_cut = val;
+		goto out;
+	}
+
 	if (buf[0] == '1')
 		val = 1;
 	else if (buf[0] == '0')
@@ -336,6 +369,8 @@
 		d->chk_gen = val;
 	else if (dent == d->dfs_chk_io)
 		d->chk_io = val;
+	else if (dent == d->dfs_chk_fastmap)
+		d->chk_fastmap = val;
 	else if (dent == d->dfs_disable_bgt)
 		d->disable_bgt = val;
 	else if (dent == d->dfs_emulate_bitflips)
@@ -406,6 +441,13 @@
 		goto out_remove;
 	d->dfs_chk_io = dent;
 
+	fname = "chk_fastmap";
+	dent = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, (void *)ubi_num,
+				   &dfs_fops);
+	if (IS_ERR_OR_NULL(dent))
+		goto out_remove;
+	d->dfs_chk_fastmap = dent;
+
 	fname = "tst_disable_bgt";
 	dent = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, (void *)ubi_num,
 				   &dfs_fops);
@@ -427,13 +469,34 @@
 		goto out_remove;
 	d->dfs_emulate_io_failures = dent;
 
+	fname = "tst_emulate_power_cut";
+	dent = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, (void *)ubi_num,
+				   &dfs_fops);
+	if (IS_ERR_OR_NULL(dent))
+		goto out_remove;
+	d->dfs_emulate_power_cut = dent;
+
+	fname = "tst_emulate_power_cut_min";
+	dent = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, (void *)ubi_num,
+				   &dfs_fops);
+	if (IS_ERR_OR_NULL(dent))
+		goto out_remove;
+	d->dfs_power_cut_min = dent;
+
+	fname = "tst_emulate_power_cut_max";
+	dent = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, (void *)ubi_num,
+				   &dfs_fops);
+	if (IS_ERR_OR_NULL(dent))
+		goto out_remove;
+	d->dfs_power_cut_max = dent;
+
 	return 0;
 
 out_remove:
 	debugfs_remove_recursive(d->dfs_dir);
 out:
 	err = dent ? PTR_ERR(dent) : -ENODEV;
-	ubi_err("cannot create \"%s\" debugfs file or directory, error %d\n",
+	ubi_err(ubi, "cannot create \"%s\" debugfs file or directory, error %d\n",
 		fname, err);
 	return err;
 }
@@ -447,3 +510,36 @@
 	if (IS_ENABLED(CONFIG_DEBUG_FS))
 		debugfs_remove_recursive(ubi->dbg.dfs_dir);
 }
+
+/**
+ * ubi_dbg_power_cut - emulate a power cut if it is time to do so
+ * @ubi: UBI device description object
+ * @caller: Flags set to indicate from where the function is being called
+ *
+ * Returns non-zero if a power cut was emulated, zero if not.
+ */
+int ubi_dbg_power_cut(struct ubi_device *ubi, int caller)
+{
+	unsigned int range;
+
+	if ((ubi->dbg.emulate_power_cut & caller) == 0)
+		return 0;
+
+	if (ubi->dbg.power_cut_counter == 0) {
+		ubi->dbg.power_cut_counter = ubi->dbg.power_cut_min;
+
+		if (ubi->dbg.power_cut_max > ubi->dbg.power_cut_min) {
+			range = ubi->dbg.power_cut_max - ubi->dbg.power_cut_min;
+			ubi->dbg.power_cut_counter += prandom_u32() % range;
+		}
+		return 0;
+	}
+
+	ubi->dbg.power_cut_counter--;
+	if (ubi->dbg.power_cut_counter)
+		return 0;
+
+	ubi_msg(ubi, "XXXXXXXXXXXXXXX emulating a power cut XXXXXXXXXXXXXXXX");
+	ubi_ro_mode(ubi);
+	return 1;
+}