x86: coreboot: Allow building an expo for editing CMOS config

Coreboot provides the CMOS layout in the tables it passes to U-Boot.
Use that to build an editor for the CMOS settings.

Signed-off-by: Simon Glass <[e-mail]>

boot/Makefile

···
 
 obj-$(CONFIG_$(PHASE_)EXPO) += expo.o scene.o expo_build.o
 obj-$(CONFIG_$(PHASE_)EXPO) += scene_menu.o scene_textline.o
+ifdef CONFIG_COREBOOT_SYSINFO
+obj-$(CONFIG_$(SPL_TPL_)EXPO) += expo_build_cb.o
+endif
 
 obj-$(CONFIG_$(PHASE_)BOOTMETH_VBE) += vbe.o
 obj-$(CONFIG_$(PHASE_)BOOTMETH_VBE_REQUEST) += vbe_request.o

boot/expo_build_cb.c

···
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Building an expo from an FDT description
+ *
+ * Copyright 2022 Google LLC
+ * Written by Simon Glass <[e-mail]>
+ */
+
+#define LOG_CATEGORY	LOGC_EXPO
+
+#include <cedit.h>
+#include <ctype.h>
+#include <errno.h>
+#include <expo.h>
+#include <log.h>
+#include <malloc.h>
+#include <vsprintf.h>
+#include <asm/cb_sysinfo.h>
+
+/**
+ * struct build_info - Information to use when building
+ */
+struct build_info {
+	const struct cb_cmos_option_table *tab;
+	struct cedit_priv *priv;
+};
+
+/**
+ * convert_to_title() - Convert text to 'title' format and allocate a string
+ *
+ * Converts "this_is_a_test" to "This is a test" so it looks better
+ *
+ * @text: Text to convert
+ * Return: Allocated string, or NULL if out of memory
+ */
+static char *convert_to_title(const char *text)
+{
+	int len = strlen(text);
+	char *buf, *s;
+
+	buf = malloc(len + 1);
+	if (!buf)
+		return NULL;
+
+	for (s = buf; *text; s++, text++) {
+		if (s == buf)
+			*s = toupper(*text);
+		else if (*text == '_')
+			*s = ' ';
+		else
+			*s = *text;
+	}
+	*s = '\0';
+
+	return buf;
+}
+
+/**
+ * menu_build() - Build a menu and add it to a scene
+ *
+ * See doc/developer/expo.rst for a description of the format
+ *
+ * @info: Build information
+ * @entry: CMOS entry to build a menu for
+ * @scn: Scene to add the menu to
+ * @objp: Returns the object pointer
+ * Returns: 0 if OK, -ENOMEM if out of memory, -EINVAL if there is a format
+ * error, -ENOENT if there is a references to a non-existent string
+ */
+static int menu_build(struct build_info *info,
+		      const struct cb_cmos_entries *entry, struct scene *scn,
+		      struct scene_obj **objp)
+{
+	struct scene_obj_menu *menu;
+	const void *ptr, *end;
+	uint menu_id;
+	char *title;
+	int ret, i;
+
+	ret = scene_menu(scn, entry->name, 0, &menu);
+	if (ret < 0)
+		return log_msg_ret("men", ret);
+	menu_id = ret;
+
+	title = convert_to_title(entry->name);
+	if (!title)
+		return log_msg_ret("con", -ENOMEM);
+
+	/* Set the title */
+	ret = scene_txt_str(scn, "title", 0, 0, title, NULL);
+	if (ret < 0)
+		return log_msg_ret("tit", ret);
+	menu->title_id = ret;
+
+	end = (void *)info->tab + info->tab->size;
+	for (ptr = (void *)info->tab + info->tab->header_length, i = 0;
+	     ptr < end; i++) {
+		const struct cb_cmos_enums *enums = ptr;
+		struct scene_menitem *item;
+		uint label;
+
+		ptr += enums->size;
+		if (enums->tag != CB_TAG_OPTION_ENUM ||
+		    enums->config_id != entry->config_id)
+			continue;
+
+		ret = scene_txt_str(scn, enums->text, 0, 0, enums->text, NULL);
+		if (ret < 0)
+			return log_msg_ret("tit", ret);
+		label = ret;
+
+		ret = scene_menuitem(scn, menu_id, simple_xtoa(i), 0, 0, label,
+				     0, 0, 0, &item);
+		if (ret < 0)
+			return log_msg_ret("mi", ret);
+		item->value = enums->value;
+	}
+	*objp = &menu->obj;
+
+	return 0;
+}
+
+/**
+ * scene_build() - Build a scene and all its objects
+ *
+ * See doc/developer/expo.rst for a description of the format
+ *
+ * @info: Build information
+ * @scn: Scene to add the object to
+ * Returns: 0 if OK, -ENOMEM if out of memory, -EINVAL if there is a format
+ * error, -ENOENT if there is a references to a non-existent string
+ */
+static int scene_build(struct build_info *info, struct expo *exp)
+{
+	struct scene_obj_menu *menu;
+	const void *ptr, *end;
+	struct scene_obj *obj;
+	struct scene *scn;
+	uint label, menu_id;
+	int ret;
+
+	ret = scene_new(exp, "cmos", 0, &scn);
+	if (ret < 0)
+		return log_msg_ret("scn", ret);
+
+	ret = scene_txt_str(scn, "title", 0, 0, "CMOS RAM settings", NULL);
+	if (ret < 0)
+		return log_msg_ret("add", ret);
+	scn->title_id = ret;
+
+	ret = scene_txt_str(scn, "prompt", 0, 0,
+			    "UP and DOWN to choose, ENTER to select", NULL);
+	if (ret < 0)
+		return log_msg_ret("add", ret);
+
+	end = (void *)info->tab + info->tab->size;
+	for (ptr = (void *)info->tab + info->tab->header_length; ptr < end;) {
+		const struct cb_cmos_entries *entry;
+		const struct cb_record *rec = ptr;
+
+		entry = ptr;
+		ptr += rec->size;
+		if (rec->tag != CB_TAG_OPTION)
+			continue;
+		switch (entry->config) {
+		case 'e':
+			ret = menu_build(info, entry, scn, &obj);
+			break;
+		default:
+			continue;
+		}
+		if (ret < 0)
+			return log_msg_ret("add", ret);
+
+		obj->start_bit = entry->bit;
+		obj->bit_length = entry->length;
+	}
+
+	ret = scene_menu(scn, "save", EXPOID_SAVE, &menu);
+	if (ret < 0)
+		return log_msg_ret("men", ret);
+	menu_id = ret;
+
+	ret = scene_txt_str(scn, "save", 0, 0, "Save and exit", NULL);
+	if (ret < 0)
+		return log_msg_ret("sav", ret);
+	label = ret;
+	ret = scene_menuitem(scn, menu_id, "save", 0, 0, label,
+			     0, 0, 0, NULL);
+	if (ret < 0)
+		return log_msg_ret("mi", ret);
+
+	ret = scene_menu(scn, "nosave", EXPOID_DISCARD, &menu);
+	if (ret < 0)
+		return log_msg_ret("men", ret);
+	menu_id = ret;
+
+	ret = scene_txt_str(scn, "nosave", 0, 0, "Exit without saving", NULL);
+	if (ret < 0)
+		return log_msg_ret("nos", ret);
+	label = ret;
+	ret = scene_menuitem(scn, menu_id, "exit", 0, 0, label,
+			     0, 0, 0, NULL);
+	if (ret < 0)
+		return log_msg_ret("mi", ret);
+
+	return 0;
+}
+
+static int build_it(struct build_info *info, struct expo **expp)
+{
+	struct expo *exp;
+	int ret;
+
+	ret = expo_new("coreboot", NULL, &exp);
+	if (ret)
+		return log_msg_ret("exp", ret);
+	expo_set_dynamic_start(exp, EXPOID_BASE_ID);
+
+	ret = scene_build(info, exp);
+	if (ret < 0)
+		return log_msg_ret("scn", ret);
+
+	*expp = exp;
+
+	return 0;
+}
+
+int cb_expo_build(struct expo **expp)
+{
+	struct build_info info;
+	struct expo *exp;
+	int ret;
+
+	info.tab = lib_sysinfo.option_table;
+	if (!info.tab)
+		return log_msg_ret("tab", -ENOENT);
+
+	ret = build_it(&info, &exp);
+	if (ret)
+		return log_msg_ret("bui", ret);
+	*expp = exp;
+
+	return 0;
+}

cmd/cedit.c

···
 	return 0;
 }
 
+#ifdef CONFIG_COREBOOT_SYSINFO
+static int do_cedit_cb_load(struct cmd_tbl *cmdtp, int flag, int argc,
+			    char *const argv[])
+{
+	struct expo *exp;
+	int ret;
+
+	if (argc > 1)
+		return CMD_RET_USAGE;
+
+	ret = cb_expo_build(&exp);
+	if (ret) {
+		printf("Failed to build expo: %dE\n", ret);
+		return CMD_RET_FAILURE;
+	}
+
+	cur_exp = exp;
+
+	return 0;
+}
+#endif /* CONFIG_COREBOOT_SYSINFO */
+
 static int do_cedit_write_fdt(struct cmd_tbl *cmdtp, int flag, int argc,
 			      char *const argv[])
 {
···
 
 U_BOOT_LONGHELP(cedit,
 	"load <interface> <dev[:part]> <filename>   - load config editor\n"
+#ifdef CONFIG_COREBOOT_SYSINFO
+	"cb_load                                          - load coreboot CMOS editor\n"
+#endif
 	"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"
···
 
 U_BOOT_CMD_WITH_SUBCMDS(cedit, "Configuration editor", cedit_help_text,
 	U_BOOT_SUBCMD_MKENT(load, 5, 1, do_cedit_load),
+#ifdef CONFIG_COREBOOT_SYSINFO
+	U_BOOT_SUBCMD_MKENT(cb_load, 5, 1, do_cedit_cb_load),
+#endif
 	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),

doc/board/coreboot/coreboot.rst

···
 boot as a coreboot payload, based on a known-good build of coreboot.
 
 To update the `coreboot.rom` file which is used, see ``tools/Dockerfile``
+
+Editing CMOS RAM settings
+-------------------------
+
+U-Boot supports creating a configuration editor to edit coreboot CMOS-RAM
+settings. See :ref:`cedit_cb_load`.

doc/develop/cedit.rst

···
 
 For now, reading and writing settings is not automatic. See the
 :doc:`../usage/cmd/cedit` for how to do this on the command line or in a
-script.
+script. For x86 devices, see :ref:`cedit_cb_load`.

doc/usage/cmd/cbcmos.rst

···
     Checksum 6600 written
     => cbc check
     =>
+
+See also :ref:`cedit_cb_load` which shows an example that includes the
+configuration editor.

doc/usage/cmd/cedit.rst

···
     cedit write_env [-v]
     cedit read_env [-v]
     cedit write_cmos [-v] [dev]
+    cedit cb_load
 
 Description
 -----------
···
 Normally the first RTC device is used to hold the data. You can specify a
 different device by name using the `dev` parameter.
 
+.. _cedit_cb_load:
+
+cedit cb_load
+~~~~~~~~~~~~~
+
+This is supported only on x86 devices booted from coreboot. It creates a new
+configuration editor which can be used to edit CMOS settings.
 
 Example
 -------
···
 
     => cedit write_cmos rtc@43
     =>
+
+This example shows editing coreboot CMOS-RAM settings. A script could be used
+to automate this::
+
+    => cbsysinfo
+    Coreboot table at 500, size 5c4, records 1d (dec 29), decoded to 000000007dce3f40, forwarded to 000000007ff9a000
+
+    CPU KHz     : 0
+    Serial I/O port: 00000000
+       base        : 00000000
+       pointer     : 000000007ff9a370
+       type        : 1
+       base        : 000003f8
+       baud        : 0d115200
+       regwidth    : 1
+       input_hz    : 0d1843200
+       PCI addr    : 00000010
+    Mem ranges  : 7
+              id: type               ||   base        ||   size
+               0: 10:table    0000000000000000 0000000000001000
+               1: 01:ram      0000000000001000 000000000009f000
+               2: 02:reserved 00000000000a0000 0000000000060000
+               3: 01:ram      0000000000100000 000000007fe6d000
+               4: 10:table    000000007ff6d000 0000000000093000
+               5: 02:reserved 00000000fec00000 0000000000001000
+               6: 02:reserved 00000000ff800000 0000000000800000
+    option_table: 000000007ff9a018
+     Bit  Len  Cfg  ID  Name
+       0  180    r   0  reserved_memory
+     180    1    e   4  boot_option            0:Fallback 1:Normal
+     184    4    h   0  reboot_counter
+     190    8    r   0  reserved_century
+     1b8    8    r   0  reserved_ibm_ps2_century
+     1c0    1    e   1  power_on_after_fail    0:Disable 1:Enable
+     1c4    4    e   6  debug_level            5:Notice 6:Info 7:Debug 8:Spew
+     1d0   80    r   0  vbnv
+     3f0   10    h   0  check_sum
+    CMOS start  : 1c0
+       CMOS end    : 1cf
+       CMOS csum loc: 3f0
+    VBNV start  : ffffffff
+    VBNV size   : ffffffff
+    ...
+    Unimpl.     : 10 37 40
+
+Check that the CMOS RAM checksum is correct, then create a configuration editor
+and load the settings from CMOS RAM::
+
+    => cbcmos check
+    => cedit cb
+    => cedit read_cmos
+
+Now run the cedit. In this case the user selected 'save' so `cedit run` returns
+success::
+
+    => if cedit run; then cedit write_cmos -v; fi
+    Write 2 bytes from offset 30 to 38
+    => echo $?
+    0
+
+Update the checksum in CMOS RAM::
+
+    => cbcmos check
+    Checksum 6100 error: calculated 7100
+    => cbcmos update
+    Checksum 7100 written
+    => cbcmos check
+    =>

include/expo.h

···
  */
 int expo_build(ofnode root, struct expo **expp);
 
+/**
+ * cb_expo_build() - Build an expo for coreboot CMOS RAM
+ *
+ * @expp: Returns the expo created
+ * Return: 0 if OK, -ve on error
+ */
+int cb_expo_build(struct expo **expp);
+
 #endif /*__EXPO_H */

test/cmd/coreboot.c

···
  * Written by Simon Glass <[e-mail]>
  */
 
+#include <cedit.h>
 #include <command.h>
 #include <dm.h>
+#include <expo.h>
 #include <rtc.h>
+#include <test/cedit-test.h>
 #include <test/cmd.h>
 #include <test/test.h>
 #include <test/ut.h>
+#include "../../boot/scene_internal.h"
 
 enum {
 	CSUM_LOC	= 0x3f0 / 8,
···
 	return 0;
 }
 CMD_TEST(test_cmd_cbcmos, UTF_CONSOLE);
+
+/* test 'cedit cb_load' command */
+static int test_cmd_cedit_cb_load(struct unit_test_state *uts)
+{
+	struct scene_obj_menu *menu;
+	struct video_priv *vid_priv;
+	struct scene_obj_txt *txt;
+	struct scene *scn;
+	struct expo *exp;
+	int scn_id;
+
+	ut_assertok(run_command("cedit cb_load", 0));
+	ut_assertok(run_command("cedit read_cmos", 0));
+	ut_assert_console_end();
+
+	exp = cur_exp;
+	scn_id = cedit_prepare(exp, &vid_priv, &scn);
+	ut_assert(scn_id > 0);
+	ut_assertnonnull(scn);
+
+	/* just do a very basic test that the first menu is present */
+	menu = scene_obj_find(scn, scn->highlight_id, SCENEOBJT_NONE);
+	ut_assertnonnull(menu);
+
+	txt = scene_obj_find(scn, menu->title_id, SCENEOBJT_NONE);
+	ut_assertnonnull(txt);
+	ut_asserteq_str("Boot option", expo_get_str(exp, txt->str_id));
+
+	return 0;
+}
+CMD_TEST(test_cmd_cedit_cb_load, UTF_CONSOLE);