cli: Add a command to show cmdline history

There is a function for this but it is never used. Showing the history is
a useful feature, so add a new 'history' command.

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

cmd/Kconfig

@@ -176,6 +176,13 @@ config CMD_FWU_METADATA
 	help
 	  Command to read the metadata and dump it's contents
 
+config CMD_HISTORY
+	bool "history"
+	depends on CMDLINE_EDITING
+	help
+	  Show the command-line history, i.e. a list of commands that are in
+	  the history buffer.
+
 config CMD_LICENSE
 	bool "license"
 	select BUILD_BIN2C

cmd/Makefile

@@ -91,6 +91,7 @@ obj-$(CONFIG_CMD_FUSE) += fuse.o
 obj-$(CONFIG_CMD_FWU_METADATA) += fwu_mdata.o
 obj-$(CONFIG_CMD_GETTIME) += gettime.o
 obj-$(CONFIG_CMD_GPIO) += gpio.o
+obj-$(CONFIG_CMD_HISTORY) += history.o
 obj-$(CONFIG_CMD_HVC) += smccc.o
 obj-$(CONFIG_CMD_I2C) += i2c.o
 obj-$(CONFIG_CMD_IOTRACE) += iotrace.o

cmd/history.c

@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2023 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <common.h>
+#include <command.h>
+#include <cli.h>
+
+static int do_history(struct cmd_tbl *cmdtp, int flag, int argc,
+		      char *const argv[])
+{
+	cread_print_hist_list();
+
+	return 0;
+}
+
+U_BOOT_CMD(
+	history,	CONFIG_SYS_MAXARGS,	1,	do_history,
+	"print command history",
+	""
+);

common/cli_readline.c

@@ -160,8 +160,7 @@ static char *hist_next(void)
 	return ret;
 }
 
-#ifndef CONFIG_CMDLINE_EDITING
-static void cread_print_hist_list(void)
+void cread_print_hist_list(void)
 {
 	int i;
 	unsigned long n;
@@ -179,7 +178,6 @@ static void cread_print_hist_list(void)
 		i++;
 	}
 }
-#endif /* CONFIG_CMDLINE_EDITING */
 
 #define BEGINNING_OF_LINE() {			\
 	while (num) {				\

doc/usage/cmd/history.rst

@@ -0,0 +1,67 @@
+.. SPDX-License-Identifier: GPL-2.0+:
+
+history command
+===============
+
+Synopis
+-------
+
+::
+
+    history
+
+Description
+-----------
+
+The *history* command shows a list of previously entered commands on the
+command line. When U-Boot starts, this it is initially empty. Each new command
+entered is added to the list.
+
+Normally these commands can be accessed by pressing the `up arrow` and
+`down arrow` keys, which cycle through the list. The `history` command provides
+a simple way to view the list.
+
+Example
+-------
+
+This example shows entering three commands, then `history`. Note that `history`
+itself is added to the list.
+
+::
+
+    => bootflow scan -l
+    Scanning for bootflows in all bootdevs
+    Seq  Method       State   Uclass    Part  Name                      Filename
+    ---  -----------  ------  --------  ----  ------------------------  ----------------
+    Scanning global bootmeth 'firmware0':
+    Hunting with: simple_bus
+    Found 2 extension board(s).
+    Scanning bootdev 'mmc2.bootdev':
+    Scanning bootdev 'mmc1.bootdev':
+      0  extlinux     ready   mmc          1  mmc1.bootdev.part_1       /extlinux/extlinux.conf
+    No more bootdevs
+    ---  -----------  ------  --------  ----  ------------------------  ----------------
+    (1 bootflow, 1 valid)
+    => bootflow select 0
+    => bootflow info
+    Name:      mmc1.bootdev.part_1
+    Device:    mmc1.bootdev
+    Block dev: mmc1.blk
+    Method:    extlinux
+    State:     ready
+    Partition: 1
+    Subdir:    (none)
+    Filename:  /extlinux/extlinux.conf
+    Buffer:    aebdea0
+    Size:      253 (595 bytes)
+    OS:        Fedora-Workstation-armhfp-31-1.9 (5.3.7-301.fc31.armv7hl)
+    Cmdline:   (none)
+    Logo:      (none)
+    FDT:       <NULL>
+    Error:     0
+    => history
+    bootflow scan -l
+    bootflow select 0
+    bootflow info
+    history
+    =>

doc/usage/index.rst

@@ -67,6 +67,7 @@ Shell commands
    cmd/fwu_mdata
    cmd/gpio
    cmd/gpt
+   cmd/history
    cmd/host
    cmd/imxtract
    cmd/load

include/cli.h

@@ -229,4 +229,7 @@ void cli_ch_init(struct cli_ch_state *cch);
  */
 int cli_ch_process(struct cli_ch_state *cch, int ichar);
 
+/** cread_print_hist_list() - Print the command-line history list */
+void cread_print_hist_list(void);
+
 #endif

test/cmd/Makefile

@@ -14,6 +14,7 @@ obj-$(CONFIG_CMD_ADDRMAP) += addrmap.o
 obj-$(CONFIG_CMD_BDI) += bdinfo.o
 obj-$(CONFIG_CMD_FDT) += fdt.o
 obj-$(CONFIG_CONSOLE_TRUETYPE) += font.o
+obj-$(CONFIG_CMD_HISTORY) += history.o
 obj-$(CONFIG_CMD_LOADM) += loadm.o
 obj-$(CONFIG_CMD_MEM_SEARCH) += mem_search.o
 ifdef CONFIG_CMD_PCI

test/cmd/history.c

@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Tests for history command
+ *
+ * Copyright 2023 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <common.h>
+#include <cli.h>
+#include <command.h>
+#include <test/lib.h>
+#include <test/test.h>
+#include <test/ut.h>
+
+static int lib_test_history(struct unit_test_state *uts)
+{
+	static const char cmd1[] = "setenv fred hello";
+	static const char cmd2[] = "print fred";
+
+	/* running commands directly does not add to history */
+	ut_assertok(run_command(cmd1, 0));
+	ut_assert_console_end();
+	ut_assertok(run_command("history", 0));
+	ut_assert_console_end();
+
+	/* enter commands via the console */
+	console_in_puts(cmd1);
+	console_in_puts("\n");
+	ut_asserteq(strlen(cmd1), cli_readline(""));
+	ut_assert_nextline(cmd1);
+
+	console_in_puts(cmd2);
+	console_in_puts("\n");
+	ut_asserteq(strlen(cmd2), cli_readline(""));
+	ut_assert_nextline(cmd2);
+
+	ut_assertok(run_command("print fred", 0));
+	ut_assert_nextline("fred=hello");
+	ut_assert_console_end();
+
+	ut_assertok(run_command("history", 0));
+	ut_assert_nextline(cmd1);
+	ut_assert_nextline(cmd2);
+	ut_assert_console_end();
+
+	return 0;
+}
+LIB_TEST(lib_test_history, UT_TESTF_CONSOLE_REC);