doc: man-page for blkcache
Provide a man-page for the blkcache command.
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/usage/cmd/blkcache.rst b/doc/usage/cmd/blkcache.rst
new file mode 100644
index 0000000..d3b2254
--- /dev/null
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@@ -0,0 +1,74 @@
+.. SPDX-License-Identifier: GPL-2.0+
+.. Copyright 2023, Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
+
+blkcache command
+================
+
+Synopsis
+--------
+
+::
+
+ blkcache show
+ blkcache configure <blocks> <entries>
+
+Description
+-----------
+
+The *blkcache* command is used to control the size of the block cache and to
+display statistics.
+
+The block cache buffers data read from block devices. This speeds up the access
+to file-systems.
+
+show
+ show and reset statistics
+
+configure
+ set the maximum number of cache entries and the maximum number of blocks per
+ entry
+
+blocks
+ maximum number of blocks per cache entry. The block size is device specific.
+ The initial value is 8.
+
+entries
+ maximum number of entries in the cche. The initial value is 32.
+
+Example
+-------
+
+.. code-block::
+
+ => blkcache show
+ hits: 296
+ misses: 149
+ entries: 7
+ max blocks/entry: 8
+ max cache entries: 32
+ => blkcache show
+ hits: 0
+ misses: 0
+ entries: 7
+ max blocks/entry: 8
+ max cache entries: 32
+ => blkcache configure 16 64
+ changed to max of 64 entries of 16 blocks each
+ => blkcache show
+ hits: 0
+ misses: 0
+ entries: 0
+ max blocks/entry: 16
+ max cache entries: 64
+ =>
+
+Configuration
+-------------
+
+The blkcache command is only available if CONFIG_CMD_BLOCK_CACHE=y.
+
+Return code
+-----------
+
+If the command succeeds, the return code $? is set 0 (true). In case of an
+error the return code is set to 1 (false).
diff --git a/doc/usage/index.rst b/doc/usage/index.rst
index 53e4aee..9284d15 100644
--- a/doc/usage/index.rst
+++ b/doc/usage/index.rst
@@ -23,6 +23,7 @@
cmd/addrmap
cmd/askenv
cmd/base
+ cmd/blkcache
cmd/bootd
cmd/bootdev
cmd/bootefi