doc: man-page for cp

Add a man-page for the cp command.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

doc/usage/cmd/cp.rst

@@ -0,0 +1,83 @@
+.. SPDX-License-Identifier: GPL-2.0+:
+
+cp command
+==========
+
+Synopsis
+--------
+
+::
+
+    cp source target count
+    cp.b source target count
+    cp.w source target count
+    cp.l source target count
+    cp.q source target count
+
+Description
+-----------
+
+The cp command is used to copy *count* chunks of memory from the *source*
+address to the *target* address. If the *target* address points to NOR flash,
+the flash is programmed.
+
+The number bytes in one chunk is defined by the suffix defaulting to 4 bytes:
+
+====== ==========
+suffix chunk size
+====== ==========
+.b     1 byte
+.w     2 bytes
+.l     4 bytes
+.q     8 bytes
+<none> 4 bytes
+====== ==========
+
+source
+        source address, hexadecimal
+
+target
+        target address, hexadecimal
+
+count
+        number of words to be copied, hexadecimal
+
+Examples
+--------
+
+The example device has a NOR flash where the lower part of the flash is
+protected. We first copy to RAM, then to unprotected flash. Last we try to
+write to protectd flash.
+
+::
+
+    => mtd list
+    List of MTD devices:
+    * nor0
+      - device: flash@0
+      - parent: root_driver
+      - driver: cfi_flash
+      - path: /flash@0
+      - type: NOR flash
+      - block size: 0x20000 bytes
+      - min I/O: 0x1 bytes
+      - 0x000000000000-0x000002000000 : "nor0"
+    => cp.b 4020000 5000000 200000
+    => cp.b 4020000 1e00000 20000
+    Copy to Flash... done
+    => cp.b 4020000 0 20000
+    Copy to Flash... Can't write to protected Flash sectors
+    =>
+
+Configuration
+-------------
+
+The cp command is available if CONFIG_CMD_MEMORY=y. Support for 64 bit words
+(cp.q) depends on CONFIG_MEM_SUPPORT_64BIT_DATA=y. Copying to flash depends on
+CONFIG_MTD_NOR_FLASH=y.
+
+Return value
+------------
+
+The return value $? is set to 0 (true) if the command was successfully,
+1 (false) otherwise.

doc/usage/index.rst

@@ -41,6 +41,7 @@ Shell commands
    cmd/cmp
    cmd/coninfo
    cmd/conitrace
+   cmd/cp
    cmd/cyclic
    cmd/dm
    cmd/ebtupdate