expo: cedit: Support reading settings from environment vars

Add a command to read cedit settings from environment variables so that
they can be restored as part of the environment.

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

boot/cedit.c

@@ -439,3 +439,48 @@ int cedit_write_settings_env(struct expo *exp, bool verbose)
 
 	return 0;
 }
+
+static int h_read_settings_env(struct scene_obj *obj, void *vpriv)
+{
+	struct cedit_iter_priv *priv = vpriv;
+	struct scene_obj_menu *menu;
+	char var[60];
+	int val, ret;
+
+	if (obj->type != SCENEOBJT_MENU)
+		return 0;
+
+	menu = (struct scene_obj_menu *)obj;
+	val = menu->cur_item_id;
+	snprintf(var, sizeof(var), "c.%s", obj->name);
+
+	val = env_get_ulong(var, 10, 0);
+	if (priv->verbose)
+		printf("%s=%d\n", var, val);
+	if (!val)
+		return log_msg_ret("get", -ENOENT);
+
+	/*
+	 * note that no validation is done here, to make sure the ID is valid
+	 * and actually points to a menu item
+	 */
+	menu->cur_item_id = val;
+
+	return 0;
+}
+
+int cedit_read_settings_env(struct expo *exp, bool verbose)
+{
+	struct cedit_iter_priv priv;
+	int ret;
+
+	/* write out the items */
+	priv.verbose = verbose;
+	ret = expo_iter_scene_objs(exp, h_read_settings_env, &priv);
+	if (ret) {
+		log_debug("Failed to read settings from env (err=%d)\n", ret);
+		return log_msg_ret("set", ret);
+	}
+
+	return 0;
+}

cmd/cedit.c

@@ -156,6 +156,26 @@ static int do_cedit_write_env(struct cmd_tbl *cmdtp, int flag, int argc,
 	return 0;
 }
 
+static int do_cedit_read_env(struct cmd_tbl *cmdtp, int flag, int argc,
+			     char *const argv[])
+{
+	bool verbose;
+	int ret;
+
+	if (check_cur_expo())
+		return CMD_RET_FAILURE;
+
+	verbose = argc > 1 && !strcmp(argv[1], "-v");
+
+	ret = cedit_read_settings_env(cur_exp, verbose);
+	if (ret) {
+		printf("Failed to read settings from environment: %dE\n", ret);
+		return CMD_RET_FAILURE;
+	}
+
+	return 0;
+}
+
 static int do_cedit_run(struct cmd_tbl *cmdtp, int flag, int argc,
 			char *const argv[])
 {
@@ -187,6 +207,7 @@ static char cedit_help_text[] =
 	"load <interface> <dev[:part]> <filename>   - load config editor\n"
 	"cedit read_fdt <i/f> <dev[:part]> <filename>     - read settings\n"
 	"cedit write_fdt <i/f> <dev[:part]> <filename>    - write settings\n"
+	"cedit read_env [-v]                              - read settings from env vars\n"
 	"cedit write_env [-v]                             - write settings to env vars\n"
 	"cedit run                                        - run config editor";
 #endif /* CONFIG_SYS_LONGHELP */
@@ -195,6 +216,7 @@ U_BOOT_CMD_WITH_SUBCMDS(cedit, "Configuration editor", cedit_help_text,
 	U_BOOT_SUBCMD_MKENT(load, 5, 1, do_cedit_load),
 	U_BOOT_SUBCMD_MKENT(read_fdt, 5, 1, do_cedit_read_fdt),
 	U_BOOT_SUBCMD_MKENT(write_fdt, 5, 1, do_cedit_write_fdt),
+	U_BOOT_SUBCMD_MKENT(read_env, 2, 1, do_cedit_read_env),
 	U_BOOT_SUBCMD_MKENT(write_env, 2, 1, do_cedit_write_env),
 	U_BOOT_SUBCMD_MKENT(run, 1, 1, do_cedit_run),
 );

doc/usage/cmd/cedit.rst

@@ -13,6 +13,7 @@ Synopis
     cedit write_fdt <dev[:part]> <filename>
     cedit read_fdt <dev[:part]> <filename>
     cedit write_env [-v]
+    cedit read_env [-v]
 
 Description
 -----------
@@ -53,6 +54,16 @@ cedit read_fdt
 Reads the user settings from a devicetree file and updates the cedit with those
 settings.
 
+cedit read_env
+~~~~~~~~~~~~~~
+
+Reads the settings from the environment variables. For each menu item `<name>`,
+cedit looks for a variable called `c.<name>` with the ID of the selected menu
+item.
+
+The `-v` flag enables verbose mode, where each variable is printed after it is
+read.
+
 cedit write_env
 ~~~~~~~~~~~~~~~
 
@@ -91,6 +102,10 @@ That results in::
 This shows settings being stored in the environment::
 
     => cedit write_env -v
+    c.cpu-speed=7
+    c.cpu-speed-str=2.5 GHz
+    c.power-loss=12
+    c.power-loss-str=Memory
     => print
     ...
     c.cpu-speed=6
@@ -98,3 +113,7 @@ This shows settings being stored in the environment::
     c.power-loss=10
     c.power-loss-str=Always Off
     ...
+
+    => cedit read_env -v
+    c.cpu-speed=7
+    c.power-loss=12

include/cedit.h

@@ -89,4 +89,12 @@ int cedit_read_settings(struct expo *exp, oftree tree);
  */
 int cedit_write_settings_env(struct expo *exp, bool verbose);
 
+/*
+ * cedit_read_settings_env() - Read settings from the environment
+ *
+ * @exp: Expo to read settings into
+ * @verbose: true to print each var before it is read
+ */
+int cedit_read_settings_env(struct expo *exp, bool verbose);
+
 #endif /* __CEDIT_H */

test/boot/cedit.c

@@ -114,7 +114,7 @@ static int cedit_fdt(struct unit_test_state *uts)
 }
 BOOTSTD_TEST(cedit_fdt, 0);
 
-/* Check the cedit write_env command */
+/* Check the cedit write_env and read_env commands */
 static int cedit_env(struct unit_test_state *uts)
 {
 	struct video_priv *vid_priv;
@@ -142,6 +142,16 @@ static int cedit_env(struct unit_test_state *uts)
 	ut_asserteq(7, env_get_ulong("c.cpu-speed", 10, 0));
 	ut_asserteq_str("2.5 GHz", env_get("c.cpu-speed-str"));
 
+	/* reset the expo */
+	menu->cur_item_id = ID_CPU_SPEED_1;
+
+	ut_assertok(run_command("cedit read_env -v", 0));
+	ut_assert_nextlinen("c.cpu-speed=7");
+	ut_assert_nextlinen("c.power-loss=10");
+	ut_assert_console_end();
+
+	ut_asserteq(ID_CPU_SPEED_2, menu->cur_item_id);
+
 	return 0;
 }
 BOOTSTD_TEST(cedit_env, 0);