[PATCH 4/4] Documentation for ubihealthd

[Richard Weinberger]

From: Daniel Walter <dwalter at sigma-star.at>

Add documentation for ubihealthd

Signed-off-by: Daniel Walter <dwalter at sigma-star.at>
Signed-off-by: Richard Weinberger <richard at nod.at>
---
 ubi-utils/README.ubihealthd | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 ubi-utils/README.ubihealthd

diff --git a/ubi-utils/README.ubihealthd b/ubi-utils/README.ubihealthd
new file mode 100644
index 0000000..da4501a
--- /dev/null
+++ b/ubi-utils/README.ubihealthd
@@ -0,0 +1,39 @@
+# ubihealthd
+
+ubihealthd is a small daemon which monitors ubi devices.
+The main purpose of this daemon is to read and scrub
+all PEBs of a given device over a specified amount of time.
+Additionally if a PEBs was read above a given threshold
+the complete PEB will be read to detect and fix read-disturbs.
+
+## Basic Algorithm
+
+ubihealthd currently uses 2 lists to keep track of the PEB
+which should be read/scrubbed periodically.
+Additionally after each statistics update (default: every 60 seconds)
+a PEB read is performed if the number of reads since the last time
+passes a given threshold.
+In order to allow the daemon to operate after a reboot or restart of
+the daemon, the statistics are written to a given file on shutdown or
+as soon as a SIGUSR1 is received.
+
+## Statistics File format
+The statistics file is a binary format and written as follows.
+    * number of PEBs (int64_t)
+    * next scheduled PEB for reads (int64_t)
+    * next scheduled PEB for scrubbing (int64_t)
+    * dump of all PEBs (struct peb_info)
+
+## Usage:
+ubihealthd [OPTIONS]
+
+OPTIONS
+  -h, --help		Show this message
+  -d, --device		Device to be monitored (default: /dev/ubi0)
+  -f, --file		Path to statistics save file
+  -r, --read_complete	Timeframe for reading all PEBs in seconds
+  -s, --scrub_complete	Timeframe for scrubbing all PEBs in seconds
+  -x, --read_threshold	Number of reads between two stats updates
+                      	which will trigger a PEB read
+  -v, --verbosity	Set log level (0-4)
+
-- 
2.5.0