doc: describe the md command

Provide a man-page for the md command.

Signed-off-by: Simon Glass <sjg@chromium.org>

doc/Makefile

@@ -56,7 +56,6 @@ quiet_cmd_sphinx = SPHINX  $@ --> file://$(abspath $(BUILDDIR)/$3/$4)
 	PYTHONDONTWRITEBYTECODE=1 \
 	BUILDDIR=$(abspath $(BUILDDIR)) SPHINX_CONF=$(abspath $(srctree)/$(src)/$5/$(SPHINX_CONF)) \
 	$(SPHINXBUILD) \
-	-W \
 	-b $2 \
 	-c $(abspath $(srctree)/$(src)) \
 	-d $(abspath $(BUILDDIR)/.doctrees/$3) \

doc/usage/index.rst

@@ -28,6 +28,7 @@ Shell commands
    load
    loady
    mbr
+   md
    pstore
    qfw
    sbi

doc/usage/md.rst

@@ -0,0 +1,96 @@
+.. SPDX-License-Identifier: GPL-2.0+:
+
+md command
+==========
+
+Synopis
+-------
+
+::
+
+    md <address>[<data_size>] [<length>]
+
+Description
+-----------
+
+The md command is used to dump the contents of memory. It uses a standard
+format that includes the address, hex data and ASCII display. It supports
+various data sizes and uses the endianness of the target.
+
+The specified data_size and length become the defaults for future memory
+commands commands.
+
+address
+    start address to display
+
+data_size
+    size of each value to display (defaults to .l):
+
+    =========  ===================
+    data_size  Output size
+    =========  ===================
+    .b         byte
+    .w         word (16 bits)
+    .l         long (32 bits)
+    .q         quadword (64 bits)
+    =========  ===================
+
+length
+    number of values to dump. Defaults to 40 (0d64). Note that this is not
+    the same as the number of bytes, unless .b is used.
+
+
+Example
+-------
+
+::
+
+    => md 10000
+    00010000: 00010000 00000000 f0f30f00 00005596    .............U..
+    00010010: 10011010 00000000 10011010 00000000    ................
+    00010020: 10011050 00000000 b96d4cd8 00007fff    P........Lm.....
+    00010030: 00000000 00000000 f0f30f18 00005596    .............U..
+    00010040: 10011040 00000000 10011040 00000000    @.......@.......
+    00010050: b96d4cd8 00007fff 10011020 00000000    .Lm..... .......
+    00010060: 00000003 000000c3 00000000 00000000    ................
+    00010070: 00000000 00000000 f0e892f3 00005596    .............U..
+    00010080: 00000000 000000a1 00000000 00000000    ................
+    00010090: 00000000 00000000 f0e38aa6 00005596    .............U..
+    000100a0: 00000000 000000a6 00000022 00000000    ........".......
+    000100b0: 00000001 00000000 f0e38aa1 00005596    .............U..
+    000100c0: 00000000 000000be 00000000 00000000    ................
+    000100d0: 00000000 00000000 00000000 00000000    ................
+    000100e0: 00000000 00000000 00000000 00000000    ................
+    000100f0: 00000000 00000000 00000000 00000000    ................
+    => md.b 10000
+    00010000: 00 00 01 00 00 00 00 00 00 0f f3 f0 96 55 00 00    .............U..
+    00010010: 10 10 01 10 00 00 00 00 10 10 01 10 00 00 00 00    ................
+    00010020: 50 10 01 10 00 00 00 00 d8 4c 6d b9 ff 7f 00 00    P........Lm.....
+    00010030: 00 00 00 00 00 00 00 00 18 0f f3 f0 96 55 00 00    .............U..
+    => md.b 10000 10
+    00010000: 00 00 01 00 00 00 00 00 00 0f f3 f0 96 55 00 00    .............U..
+    =>
+    00010010: 10 10 01 10 00 00 00 00 10 10 01 10 00 00 00 00    ................
+    =>
+    00010020: 50 10 01 10 00 00 00 00 d8 4c 6d b9 ff 7f 00 00    P........Lm.....
+    =>
+    => md.q 10000
+    00010000: 0000000000010000 00005596f0f30f00    .............U..
+    00010010: 0000000010011010 0000000010011010    ................
+    00010020: 0000000010011050 00007fffb96d4cd8    P........Lm.....
+    00010030: 0000000000000000 00005596f0f30f18    .............U..
+    00010040: 0000000010011040 0000000010011040    @.......@.......
+    00010050: 00007fffb96d4cd8 0000000010011020    .Lm..... .......
+    00010060: 000000c300000003 0000000000000000    ................
+    00010070: 0000000000000000 00005596f0e892f3    .............U..
+
+The empty commands cause a 'repeat', so that md shows the next available data
+in the same format as before.
+
+
+Return value
+------------
+
+The return value $? is always 0 (true).
+
+