sconfig: Ensure at least one `device` node below each `chip`

Even though `device` entries are children of `chip` entries in the
devicetree source format, the chips in the translated C structures
are only hooked up to device nodes. Hence, any chip with all its
settings will be silently dropped by sconfig if there is no device
node below it.

Let's adapt the parser to ensure that there is at least one `device`
entry. The intermediate `chipchildren_dev` rule applies until the
first `device` entry is found, then everything continues as before
with the `chipchildren` rule.

Change-Id: I54830bc1fc7d00a0605f3fe4d36a83ef57ef3312
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/51119
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

3 files changed, 160 insertions, 147 deletions

diff --git a/util/sconfig/sconfig.tab.c_shipped b/util/sconfig/sconfig.tab.c_shipped
index 6155dc0ea343..b07adcb25e43 100644
--- a/util/sconfig/sconfig.tab.c_shipped
+++ b/util/sconfig/sconfig.tab.c_shipped
@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 3.7.5.  */
+/* A Bison parser, made by GNU Bison 3.7.6.  */
 
 /* Bison implementation for Yacc-like parsers in C
 
@@ -16,7 +16,7 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
 
 /* As a special exception, you may create a larger work that contains
    part or all of the Bison parser skeleton and distribute that work
@@ -46,10 +46,10 @@
    USER NAME SPACE" below.  */
 
 /* Identify Bison output, and Bison version.  */
-#define YYBISON 30705
+#define YYBISON 30706
 
 /* Bison version string.  */
-#define YYBISON_VERSION "3.7.5"
+#define YYBISON_VERSION "3.7.6"
 
 /* Skeleton name.  */
 #define YYSKELETON_NAME "yacc.c"
@@ -157,32 +157,35 @@ enum yysymbol_kind_t
   YYSYMBOL_PIPE = 44,                      /* PIPE  */
   YYSYMBOL_YYACCEPT = 45,                  /* $accept  */
   YYSYMBOL_devtree = 46,                   /* devtree  */
-  YYSYMBOL_chipchildren = 47,              /* chipchildren  */
-  YYSYMBOL_devicechildren = 48,            /* devicechildren  */
-  YYSYMBOL_chip = 49,                      /* chip  */
-  YYSYMBOL_50_1 = 50,                      /* @1  */
-  YYSYMBOL_device = 51,                    /* device  */
-  YYSYMBOL_52_2 = 52,                      /* @2  */
-  YYSYMBOL_53_3 = 53,                      /* @3  */
-  YYSYMBOL_alias = 54,                     /* alias  */
-  YYSYMBOL_status = 55,                    /* status  */
-  YYSYMBOL_resource = 56,                  /* resource  */
-  YYSYMBOL_reference = 57,                 /* reference  */
-  YYSYMBOL_registers = 58,                 /* registers  */
-  YYSYMBOL_subsystemid = 59,               /* subsystemid  */
-  YYSYMBOL_ioapic_irq = 60,                /* ioapic_irq  */
-  YYSYMBOL_smbios_slot_desc = 61,          /* smbios_slot_desc  */
-  YYSYMBOL_fw_config_table = 62,           /* fw_config_table  */
-  YYSYMBOL_fw_config_table_children = 63,  /* fw_config_table_children  */
-  YYSYMBOL_fw_config_field_children = 64,  /* fw_config_field_children  */
-  YYSYMBOL_fw_config_field_bits = 65,      /* fw_config_field_bits  */
-  YYSYMBOL_fw_config_field_bits_repeating = 66, /* fw_config_field_bits_repeating  */
-  YYSYMBOL_fw_config_field = 67,           /* fw_config_field  */
-  YYSYMBOL_68_4 = 68,                      /* $@4  */
-  YYSYMBOL_69_5 = 69,                      /* $@5  */
-  YYSYMBOL_70_6 = 70,                      /* $@6  */
-  YYSYMBOL_fw_config_option = 71,          /* fw_config_option  */
-  YYSYMBOL_fw_config_probe = 72            /* fw_config_probe  */
+  YYSYMBOL_chipchild_nondev = 47,          /* chipchild_nondev  */
+  YYSYMBOL_chipchild = 48,                 /* chipchild  */
+  YYSYMBOL_chipchildren = 49,              /* chipchildren  */
+  YYSYMBOL_chipchildren_dev = 50,          /* chipchildren_dev  */
+  YYSYMBOL_devicechildren = 51,            /* devicechildren  */
+  YYSYMBOL_chip = 52,                      /* chip  */
+  YYSYMBOL_53_1 = 53,                      /* @1  */
+  YYSYMBOL_device = 54,                    /* device  */
+  YYSYMBOL_55_2 = 55,                      /* @2  */
+  YYSYMBOL_56_3 = 56,                      /* @3  */
+  YYSYMBOL_alias = 57,                     /* alias  */
+  YYSYMBOL_status = 58,                    /* status  */
+  YYSYMBOL_resource = 59,                  /* resource  */
+  YYSYMBOL_reference = 60,                 /* reference  */
+  YYSYMBOL_registers = 61,                 /* registers  */
+  YYSYMBOL_subsystemid = 62,               /* subsystemid  */
+  YYSYMBOL_ioapic_irq = 63,                /* ioapic_irq  */
+  YYSYMBOL_smbios_slot_desc = 64,          /* smbios_slot_desc  */
+  YYSYMBOL_fw_config_table = 65,           /* fw_config_table  */
+  YYSYMBOL_fw_config_table_children = 66,  /* fw_config_table_children  */
+  YYSYMBOL_fw_config_field_children = 67,  /* fw_config_field_children  */
+  YYSYMBOL_fw_config_field_bits = 68,      /* fw_config_field_bits  */
+  YYSYMBOL_fw_config_field_bits_repeating = 69, /* fw_config_field_bits_repeating  */
+  YYSYMBOL_fw_config_field = 70,           /* fw_config_field  */
+  YYSYMBOL_71_4 = 71,                      /* $@4  */
+  YYSYMBOL_72_5 = 72,                      /* $@5  */
+  YYSYMBOL_73_6 = 73,                      /* $@6  */
+  YYSYMBOL_fw_config_option = 74,          /* fw_config_option  */
+  YYSYMBOL_fw_config_probe = 75            /* fw_config_probe  */
 };
 typedef enum yysymbol_kind_t yysymbol_kind_t;
 
@@ -504,16 +507,16 @@ union yyalloc
 /* YYFINAL -- State number of the termination state.  */
 #define YYFINAL  2
 /* YYLAST -- Last index in YYTABLE.  */
-#define YYLAST   97
+#define YYLAST   90
 
 /* YYNTOKENS -- Number of terminals.  */
 #define YYNTOKENS  45
 /* YYNNTS -- Number of nonterminals.  */
-#define YYNNTS  28
+#define YYNNTS  31
 /* YYNRULES -- Number of rules.  */
-#define YYNRULES  53
+#define YYNRULES  57
 /* YYNSTATES -- Number of states.  */
-#define YYNSTATES  95
+#define YYNSTATES  101
 
 /* YYMAXUTOK -- Last valid token kind.  */
 #define YYMAXUTOK   299
@@ -566,12 +569,12 @@ static const yytype_int8 yytranslate[] =
   /* YYRLINE[YYN] -- Source line where rule number YYN was defined.  */
 static const yytype_uint8 yyrline[] =
 {
-       0,    26,    26,    26,    26,    28,    28,    28,    28,    28,
-      30,    30,    30,    30,    30,    30,    30,    30,    30,    32,
-      32,    41,    41,    49,    49,    57,    59,    63,    63,    65,
-      68,    71,    74,    77,    80,    83,    86,    89,    93,    96,
-      96,    99,    99,   102,   108,   108,   111,   110,   115,   115,
-     123,   123,   129,   133
+       0,    26,    26,    26,    26,    29,    29,    29,    30,    30,
+      31,    31,    32,    32,    34,    34,    34,    34,    34,    34,
+      34,    34,    34,    36,    36,    45,    45,    53,    53,    61,
+      63,    67,    67,    69,    72,    75,    78,    81,    84,    87,
+      90,    93,    97,   100,   100,   103,   103,   106,   112,   112,
+     115,   114,   119,   119,   127,   127,   133,   137
 };
 #endif
 
@@ -594,9 +597,10 @@ static const char *const yytname[] =
   "SLOT_DESC", "IO", "NUMBER", "SUBSYSTEMID", "INHERIT", "IOAPIC_IRQ",
   "IOAPIC", "PCIINT", "GENERIC", "SPI", "USB", "MMIO", "GPIO",
   "FW_CONFIG_TABLE", "FW_CONFIG_FIELD", "FW_CONFIG_OPTION",
-  "FW_CONFIG_PROBE", "PIPE", "$accept", "devtree", "chipchildren",
-  "devicechildren", "chip", "@1", "device", "@2", "@3", "alias", "status",
-  "resource", "reference", "registers", "subsystemid", "ioapic_irq",
+  "FW_CONFIG_PROBE", "PIPE", "$accept", "devtree", "chipchild_nondev",
+  "chipchild", "chipchildren", "chipchildren_dev", "devicechildren",
+  "chip", "@1", "device", "@2", "@3", "alias", "status", "resource",
+  "reference", "registers", "subsystemid", "ioapic_irq",
   "smbios_slot_desc", "fw_config_table", "fw_config_table_children",
   "fw_config_field_children", "fw_config_field_bits",
   "fw_config_field_bits_repeating", "fw_config_field", "$@4", "$@5", "$@6",
@@ -623,7 +627,7 @@ static const yytype_int16 yytoknum[] =
 };
 #endif
 
-#define YYPACT_NINF (-27)
+#define YYPACT_NINF (-61)
 
 #define yypact_value_is_default(Yyn) \
   ((Yyn) == YYPACT_NINF)
@@ -637,16 +641,17 @@ static const yytype_int16 yytoknum[] =
      STATE-NUM.  */
 static const yytype_int8 yypact[] =
 {
-     -27,     9,   -27,     2,   -27,   -27,   -27,   -27,   -11,   -27,
-     -27,     4,   -27,    43,   -13,    10,    20,    21,   -27,   -27,
-     -27,   -27,   -27,    13,   -26,   -27,    22,    14,    30,    44,
-     -27,   -27,    24,   -27,    -7,    16,    45,    37,    38,    -6,
-      13,   -26,   -27,   -27,    39,   -27,   -27,   -27,   -27,    41,
-      16,   -27,   -27,   -27,   -27,    -1,    31,   -27,   -27,   -27,
-     -27,   -27,    -3,   -27,    32,   -27,    42,    33,    34,    47,
-     -27,   -27,   -27,   -27,   -27,   -27,   -27,   -27,     1,    50,
-      49,    40,    36,    51,   -27,    46,    54,    48,    52,   -27,
-     -27,    55,   -27,   -27,   -27
+     -61,    12,   -61,    -7,   -61,   -61,   -61,   -61,   -12,    46,
+     -61,     8,   -61,    14,    11,    18,    46,    23,   -61,   -61,
+     -61,   -61,    16,    24,    17,    25,    34,   -61,   -61,    46,
+      26,    10,   -61,    13,    51,    41,    42,   -61,   -61,   -61,
+     -61,   -61,    31,   -61,    -3,   -61,   -61,   -61,    44,    13,
+     -61,   -61,     2,    26,    10,   -61,   -61,    45,   -61,   -61,
+     -61,   -61,   -61,   -61,     6,    35,     0,   -61,   -61,   -61,
+      37,   -61,    50,    39,    40,    53,   -61,   -61,   -61,   -61,
+     -61,   -61,   -61,   -61,     4,    48,    54,    43,    47,    56,
+     -61,    49,    57,    55,    58,   -61,   -61,    59,   -61,   -61,
+     -61
 };
 
   /* YYDEFACT[STATE-NUM] -- Default reduction number in state STATE-NUM.
@@ -654,32 +659,35 @@ static const yytype_int8 yypact[] =
      means the default is an error.  */
 static const yytype_int8 yydefact[] =
 {
-       2,     0,     1,     0,    40,     3,     4,    19,     0,     9,
-      38,     0,    39,     0,    50,     0,     0,     0,    20,     6,
-       5,     8,     7,    48,    45,    42,     0,     0,     0,     0,
-      43,    42,     0,    46,     0,     0,    25,     0,     0,     0,
-       0,    45,    42,    51,     0,    41,    27,    28,    23,     0,
-       0,    31,    30,    49,    44,     0,     0,    18,    26,    21,
-      47,    52,     0,    18,     0,    24,     0,     0,     0,     0,
-      11,    10,    12,    16,    13,    14,    15,    17,     0,     0,
-       0,     0,     0,     0,    22,     0,    37,    32,     0,    53,
-      29,    36,    33,    34,    35
+       2,     0,     1,     0,    44,     3,     4,    23,     0,     0,
+      42,     0,    43,     0,     0,     0,     0,     0,     5,    11,
+       7,     6,    54,     0,     0,     0,     0,    13,    24,    12,
+      52,    49,    46,     0,    29,     0,     0,     9,    10,     8,
+      47,    46,     0,    50,     0,    31,    32,    27,     0,     0,
+      35,    34,     0,     0,    49,    46,    55,     0,    45,    22,
+      30,    25,    53,    48,     0,     0,     0,    22,    51,    56,
+       0,    28,     0,     0,     0,     0,    15,    14,    16,    20,
+      17,    18,    19,    21,     0,     0,     0,     0,     0,     0,
+      26,     0,    41,    36,     0,    57,    33,    40,    37,    38,
+      39
 };
 
   /* YYPGOTO[NTERM-NUM].  */
 static const yytype_int8 yypgoto[] =
 {
-     -27,   -27,   -27,    11,    19,   -27,    60,   -27,   -27,   -27,
-      17,   -27,   -27,    63,   -27,   -27,   -27,   -27,   -27,    -8,
-      53,    56,   -27,   -27,   -27,   -27,   -27,   -27
+     -61,   -61,    60,   -61,   -61,    61,    15,    -1,   -61,   -28,
+     -61,   -61,   -61,    30,   -61,   -61,   -60,   -61,   -61,   -61,
+     -61,   -61,   -22,    33,    36,   -61,   -61,   -61,   -61,   -61,
+     -61
 };
 
   /* YYDEFGOTO[NTERM-NUM].  */
 static const yytype_int8 yydefgoto[] =
 {
-       0,     1,    13,    62,    70,     9,    71,    63,    57,    50,
-      48,    72,    21,    73,    74,    75,    76,     6,     8,    34,
-      24,    33,    12,    42,    31,    25,    45,    77
+       0,     1,    16,    38,    29,    17,    66,    18,     9,    19,
+      67,    59,    49,    47,    78,    20,    21,    80,    81,    82,
+       6,     8,    44,    31,    43,    12,    55,    41,    32,    58,
+      83
 };
 
   /* YYTABLE[YYPACT[STATE-NUM]] -- What to do in state STATE-NUM.  If
@@ -687,68 +695,69 @@ static const yytype_int8 yydefgoto[] =
      number is the opposite.  If YYTABLE_NINF, syntax error.  */
 static const yytype_int8 yytable[] =
 {
-       3,    15,    16,    10,     3,    15,    16,    43,    53,     2,
-      64,    65,     3,    60,    64,    84,    23,    26,    32,     7,
-       5,    14,    27,    39,    66,    46,    47,    67,    66,    68,
-      11,    67,    19,    68,    55,    44,    44,    28,    29,    35,
-      69,    44,    30,    36,    69,    37,     3,    15,    16,     4,
-      17,    49,    38,    40,    51,    52,    56,    18,    58,    80,
-      61,    79,    81,    82,    83,    85,    86,    59,    89,    87,
-      88,    91,    94,    20,    78,    90,    22,     0,     0,    92,
-       0,    93,     0,     0,     0,    41,     0,     0,     0,     0,
-       0,     0,     0,     0,     0,     0,     0,    54
+       5,    39,    10,     3,    13,    14,    79,     3,    13,    14,
+       7,    56,     2,    70,    71,     3,    62,    70,    90,    52,
+      68,    23,    45,    46,    79,    22,    24,    72,    25,    11,
+      73,    72,    74,    64,    73,    26,    74,    28,    77,    57,
+      35,    33,    36,    75,    57,    30,    34,    75,    57,     3,
+      13,    14,     4,    15,    42,    40,    77,    48,    50,    51,
+      53,    60,    65,    91,    69,    76,    85,    86,    87,    88,
+      89,    92,    93,    95,    97,    54,   100,    27,    96,    61,
+       0,    94,    84,    76,     0,     0,    98,    99,     0,    37,
+      63
 };
 
 static const yytype_int8 yycheck[] =
 {
-       3,     4,     5,    14,     3,     4,     5,    14,    14,     0,
-      13,    14,     3,    14,    13,    14,    29,     7,    44,    17,
-       1,    17,    12,    31,    27,     9,    10,    30,    27,    32,
-      41,    30,    13,    32,    42,    42,    42,    17,    17,    17,
-      43,    42,    29,    29,    43,    15,     3,     4,     5,    40,
-       7,     6,     8,    29,    17,    17,    17,    14,    17,    17,
-      29,    29,    29,    29,    17,    15,    17,    50,    17,    29,
-      34,    17,    17,    13,    63,    29,    13,    -1,    -1,    31,
-      -1,    29,    -1,    -1,    -1,    32,    -1,    -1,    -1,    -1,
-      -1,    -1,    -1,    -1,    -1,    -1,    -1,    41
+       1,    29,    14,     3,     4,     5,    66,     3,     4,     5,
+      17,    14,     0,    13,    14,     3,    14,    13,    14,    41,
+      14,     7,     9,    10,    84,    17,    12,    27,    17,    41,
+      30,    27,    32,    55,    30,    17,    32,    14,    66,    42,
+      15,    17,     8,    43,    42,    29,    29,    43,    42,     3,
+       4,     5,    40,     7,    44,    29,    84,     6,    17,    17,
+      29,    17,    17,    15,    29,    66,    29,    17,    29,    29,
+      17,    17,    29,    17,    17,    42,    17,    16,    29,    49,
+      -1,    34,    67,    84,    -1,    -1,    31,    29,    -1,    29,
+      54
 };
 
   /* YYSTOS[STATE-NUM] -- The (internal number of the) accessing
      symbol of state STATE-NUM.  */
 static const yytype_int8 yystos[] =
 {
-       0,    46,     0,     3,    40,    49,    62,    17,    63,    50,
-      14,    41,    67,    47,    17,     4,     5,     7,    14,    49,
-      51,    57,    58,    29,    65,    70,     7,    12,    17,    17,
-      29,    69,    44,    66,    64,    17,    29,    15,     8,    64,
-      29,    65,    68,    14,    42,    71,     9,    10,    55,     6,
-      54,    17,    17,    14,    66,    64,    17,    53,    17,    55,
-      14,    29,    48,    52,    13,    14,    27,    30,    32,    43,
-      49,    51,    56,    58,    59,    60,    61,    72,    48,    29,
-      17,    29,    29,    17,    14,    15,    17,    29,    34,    17,
-      29,    17,    31,    29,    17
+       0,    46,     0,     3,    40,    52,    65,    17,    66,    53,
+      14,    41,    70,     4,     5,     7,    47,    50,    52,    54,
+      60,    61,    17,     7,    12,    17,    17,    50,    14,    49,
+      29,    68,    73,    17,    29,    15,     8,    47,    48,    54,
+      29,    72,    44,    69,    67,     9,    10,    58,     6,    57,
+      17,    17,    67,    29,    68,    71,    14,    42,    74,    56,
+      17,    58,    14,    69,    67,    17,    51,    55,    14,    29,
+      13,    14,    27,    30,    32,    43,    52,    54,    59,    61,
+      62,    63,    64,    75,    51,    29,    17,    29,    29,    17,
+      14,    15,    17,    29,    34,    17,    29,    17,    31,    29,
+      17
 };
 
   /* YYR1[YYN] -- Symbol number of symbol that rule YYN derives.  */
 static const yytype_int8 yyr1[] =
 {
-       0,    45,    46,    46,    46,    47,    47,    47,    47,    47,
-      48,    48,    48,    48,    48,    48,    48,    48,    48,    50,
-      49,    52,    51,    53,    51,    54,    54,    55,    55,    56,
-      57,    58,    59,    59,    60,    61,    61,    61,    62,    63,
-      63,    64,    64,    65,    66,    66,    68,    67,    69,    67,
-      70,    67,    71,    72
+       0,    45,    46,    46,    46,    47,    47,    47,    48,    48,
+      49,    49,    50,    50,    51,    51,    51,    51,    51,    51,
+      51,    51,    51,    53,    52,    55,    54,    56,    54,    57,
+      57,    58,    58,    59,    60,    61,    62,    62,    63,    64,
+      64,    64,    65,    66,    66,    67,    67,    68,    69,    69,
+      71,    70,    72,    70,    73,    70,    74,    75
 };
 
   /* YYR2[YYN] -- Number of symbols on the right hand side of rule YYN.  */
 static const yytype_int8 yyr2[] =
 {
-       0,     2,     0,     2,     2,     2,     2,     2,     2,     0,
-       2,     2,     2,     2,     2,     2,     2,     2,     0,     0,
-       5,     0,     8,     0,     7,     0,     2,     1,     1,     4,
-       4,     4,     3,     4,     4,     5,     4,     3,     3,     2,
-       0,     2,     0,     2,     3,     0,     0,     7,     0,     6,
-       0,     5,     3,     3
+       0,     2,     0,     2,     2,     1,     1,     1,     1,     1,
+       2,     0,     2,     2,     2,     2,     2,     2,     2,     2,
+       2,     2,     0,     0,     5,     0,     8,     0,     7,     0,
+       2,     1,     1,     4,     4,     4,     3,     4,     4,     5,
+       4,     3,     3,     2,     0,     2,     0,     2,     3,     0,
+       0,     7,     0,     6,     0,     5,     3,     3
 };
 
 
@@ -1219,7 +1228,7 @@ yyreduce:
          { cur_parent = root_parent; }
     break;
 
-  case 19: /* @1: %empty  */
+  case 23: /* @1: %empty  */
                                 {
 	(yyval.chip_instance) = new_chip_instance((yyvsp[0].string));
 	chip_enqueue_tail(cur_chip_instance);
@@ -1227,105 +1236,105 @@ yyreduce:
 }
     break;
 
-  case 20: /* chip: CHIP STRING @1 chipchildren END  */
-                         {
+  case 24: /* chip: CHIP STRING @1 chipchildren_dev END  */
+                             {
 	cur_chip_instance = chip_dequeue_tail();
 }
     break;
 
-  case 21: /* @2: %empty  */
+  case 25: /* @2: %empty  */
                                                        {
 	(yyval.dev) = new_device_raw(cur_parent, cur_chip_instance, (yyvsp[-3].number), (yyvsp[-2].string), (yyvsp[-1].string), (yyvsp[0].number));
 	cur_parent = (yyval.dev)->last_bus;
 }
     break;
 
-  case 22: /* device: DEVICE BUS NUMBER alias status @2 devicechildren END  */
+  case 26: /* device: DEVICE BUS NUMBER alias status @2 devicechildren END  */
                            {
 	cur_parent = (yyvsp[-2].dev)->parent;
 }
     break;
 
-  case 23: /* @3: %empty  */
+  case 27: /* @3: %empty  */
                                        {
 	(yyval.dev) = new_device_reference(cur_parent, cur_chip_instance, (yyvsp[-1].string), (yyvsp[0].number));
 	cur_parent = (yyval.dev)->last_bus;
 }
     break;
 
-  case 24: /* device: DEVICE REFERENCE STRING status @3 devicechildren END  */
+  case 28: /* device: DEVICE REFERENCE STRING status @3 devicechildren END  */
                            {
 	cur_parent = (yyvsp[-2].dev)->parent;
 }
     break;
 
-  case 25: /* alias: %empty  */
+  case 29: /* alias: %empty  */
                    {
 	(yyval.string) = NULL;
 }
     break;
 
-  case 26: /* alias: ALIAS STRING  */
+  case 30: /* alias: ALIAS STRING  */
                  {
 	(yyval.string) = (yyvsp[0].string);
 }
     break;
 
-  case 29: /* resource: RESOURCE NUMBER EQUALS NUMBER  */
+  case 33: /* resource: RESOURCE NUMBER EQUALS NUMBER  */
         { add_resource(cur_parent, (yyvsp[-3].number), strtol((yyvsp[-2].string), NULL, 0), strtol((yyvsp[0].string), NULL, 0)); }
     break;
 
-  case 30: /* reference: REFERENCE STRING ASSOCIATION STRING  */
+  case 34: /* reference: REFERENCE STRING ASSOCIATION STRING  */
         { add_reference(cur_chip_instance, (yyvsp[0].string), (yyvsp[-2].string)); }
     break;
 
-  case 31: /* registers: REGISTER STRING EQUALS STRING  */
+  case 35: /* registers: REGISTER STRING EQUALS STRING  */
         { add_register(cur_chip_instance, (yyvsp[-2].string), (yyvsp[0].string)); }
     break;
 
-  case 32: /* subsystemid: SUBSYSTEMID NUMBER NUMBER  */
+  case 36: /* subsystemid: SUBSYSTEMID NUMBER NUMBER  */
         { add_pci_subsystem_ids(cur_parent, strtol((yyvsp[-1].string), NULL, 16), strtol((yyvsp[0].string), NULL, 16), 0); }
     break;
 
-  case 33: /* subsystemid: SUBSYSTEMID NUMBER NUMBER INHERIT  */
+  case 37: /* subsystemid: SUBSYSTEMID NUMBER NUMBER INHERIT  */
         { add_pci_subsystem_ids(cur_parent, strtol((yyvsp[-2].string), NULL, 16), strtol((yyvsp[-1].string), NULL, 16), 1); }
     break;
 
-  case 34: /* ioapic_irq: IOAPIC_IRQ NUMBER PCIINT NUMBER  */
+  case 38: /* ioapic_irq: IOAPIC_IRQ NUMBER PCIINT NUMBER  */
         { add_ioapic_info(cur_parent, strtol((yyvsp[-2].string), NULL, 16), (yyvsp[-1].string), strtol((yyvsp[0].string), NULL, 16)); }
     break;
 
-  case 35: /* smbios_slot_desc: SLOT_DESC STRING STRING STRING STRING  */
+  case 39: /* smbios_slot_desc: SLOT_DESC STRING STRING STRING STRING  */
         { add_slot_desc(cur_parent, (yyvsp[-3].string), (yyvsp[-2].string), (yyvsp[-1].string), (yyvsp[0].string)); }
     break;
 
-  case 36: /* smbios_slot_desc: SLOT_DESC STRING STRING STRING  */
+  case 40: /* smbios_slot_desc: SLOT_DESC STRING STRING STRING  */
         { add_slot_desc(cur_parent, (yyvsp[-2].string), (yyvsp[-1].string), (yyvsp[0].string), NULL); }
     break;
 
-  case 37: /* smbios_slot_desc: SLOT_DESC STRING STRING  */
+  case 41: /* smbios_slot_desc: SLOT_DESC STRING STRING  */
         { add_slot_desc(cur_parent, (yyvsp[-1].string), (yyvsp[0].string), NULL, NULL); }
     break;
 
-  case 38: /* fw_config_table: FW_CONFIG_TABLE fw_config_table_children END  */
+  case 42: /* fw_config_table: FW_CONFIG_TABLE fw_config_table_children END  */
                                                               { }
     break;
 
-  case 43: /* fw_config_field_bits: NUMBER NUMBER  */
+  case 47: /* fw_config_field_bits: NUMBER NUMBER  */
 {
 	append_fw_config_bits(&cur_bits, strtoul((yyvsp[-1].string), NULL, 0), strtoul((yyvsp[0].string), NULL, 0));
 }
     break;
 
-  case 46: /* $@4: %empty  */
+  case 50: /* $@4: %empty  */
         { cur_field = new_fw_config_field((yyvsp[-2].string), cur_bits); }
     break;
 
-  case 47: /* fw_config_field: FW_CONFIG_FIELD STRING fw_config_field_bits fw_config_field_bits_repeating $@4 fw_config_field_children END  */
+  case 51: /* fw_config_field: FW_CONFIG_FIELD STRING fw_config_field_bits fw_config_field_bits_repeating $@4 fw_config_field_children END  */
                                      { cur_bits = NULL; }
     break;
 
-  case 48: /* $@5: %empty  */
+  case 52: /* $@5: %empty  */
                                                             {
 	cur_bits = NULL;
 	append_fw_config_bits(&cur_bits, strtoul((yyvsp[0].string), NULL, 0), strtoul((yyvsp[0].string), NULL, 0));
@@ -1333,25 +1342,25 @@ yyreduce:
 }
     break;
 
-  case 49: /* fw_config_field: FW_CONFIG_FIELD STRING NUMBER $@5 fw_config_field_children END  */
+  case 53: /* fw_config_field: FW_CONFIG_FIELD STRING NUMBER $@5 fw_config_field_children END  */
                                      { cur_bits = NULL; }
     break;
 
-  case 50: /* $@6: %empty  */
+  case 54: /* $@6: %empty  */
                                         {
 	cur_field = get_fw_config_field((yyvsp[0].string));
 }
     break;
 
-  case 51: /* fw_config_field: FW_CONFIG_FIELD STRING $@6 fw_config_field_children END  */
+  case 55: /* fw_config_field: FW_CONFIG_FIELD STRING $@6 fw_config_field_children END  */
                                      { cur_bits = NULL; }
     break;
 
-  case 52: /* fw_config_option: FW_CONFIG_OPTION STRING NUMBER  */
+  case 56: /* fw_config_option: FW_CONFIG_OPTION STRING NUMBER  */
         { add_fw_config_option(cur_field, (yyvsp[-1].string), strtoull((yyvsp[0].string), NULL, 0)); }
     break;
 
-  case 53: /* fw_config_probe: FW_CONFIG_PROBE STRING STRING  */
+  case 57: /* fw_config_probe: FW_CONFIG_PROBE STRING STRING  */
         { add_fw_config_probe(cur_parent, (yyvsp[-1].string), (yyvsp[0].string)); }
     break;
 
diff --git a/util/sconfig/sconfig.tab.h_shipped b/util/sconfig/sconfig.tab.h_shipped
index 2179499f9058..1d96a35ab66c 100644
--- a/util/sconfig/sconfig.tab.h_shipped
+++ b/util/sconfig/sconfig.tab.h_shipped
@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 3.7.5.  */
+/* A Bison parser, made by GNU Bison 3.7.6.  */
 
 /* Bison interface for Yacc-like parsers in C
 
@@ -16,7 +16,7 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
 
 /* As a special exception, you may create a larger work that contains
    part or all of the Bison parser skeleton and distribute that work
@@ -35,8 +35,8 @@
    especially those whose name start with YY_ or yy_.  They are
    private implementation details that can be changed or removed.  */
 
-#ifndef YY_YY_WORK_GIT_COREBOOT_UTIL_SCONFIG_SCONFIG_TAB_H_SHIPPED_INCLUDED
-# define YY_YY_WORK_GIT_COREBOOT_UTIL_SCONFIG_SCONFIG_TAB_H_SHIPPED_INCLUDED
+#ifndef YY_YY_HOME_ICON_COREBOOT_UTIL_SCONFIG_SCONFIG_TAB_H_SHIPPED_INCLUDED
+# define YY_YY_HOME_ICON_COREBOOT_UTIL_SCONFIG_SCONFIG_TAB_H_SHIPPED_INCLUDED
 /* Debug traces.  */
 #ifndef YYDEBUG
 # define YYDEBUG 0
@@ -122,4 +122,4 @@ extern YYSTYPE yylval;
 
 int yyparse (void);
 
-#endif /* !YY_YY_WORK_GIT_COREBOOT_UTIL_SCONFIG_SCONFIG_TAB_H_SHIPPED_INCLUDED  */
+#endif /* !YY_YY_HOME_ICON_COREBOOT_UTIL_SCONFIG_SCONFIG_TAB_H_SHIPPED_INCLUDED  */
diff --git a/util/sconfig/sconfig.y b/util/sconfig/sconfig.y
index 40c1295595b9..da6d97b1a62b 100755
--- a/util/sconfig/sconfig.y
+++ b/util/sconfig/sconfig.y
@@ -25,7 +25,11 @@ static struct fw_config_field_bits *cur_bits;
 %%
 devtree: { cur_parent = root_parent; } | devtree chip | devtree fw_config_table;
 
-chipchildren: chipchildren device | chipchildren chip | chipchildren registers | chipchildren reference | /* empty */ ;
+/* Ensure at least one `device` below each `chip`. */
+chipchild_nondev: chip | registers | reference;
+chipchild: device | chipchild_nondev;
+chipchildren: chipchildren chipchild | /* empty */ ;
+chipchildren_dev: device chipchildren | chipchild_nondev chipchildren_dev;
 
 devicechildren: devicechildren device | devicechildren chip | devicechildren resource | devicechildren subsystemid | devicechildren ioapic_irq | devicechildren smbios_slot_desc | devicechildren registers | devicechildren fw_config_probe | /* empty */ ;
 
@@ -34,7 +38,7 @@ chip: CHIP STRING /* == path */ {
 	chip_enqueue_tail(cur_chip_instance);
 	cur_chip_instance = $<chip_instance>$;
 }
-	chipchildren END {
+	chipchildren_dev END {
 	cur_chip_instance = chip_dequeue_tail();
 };