kconfig: environment symbol support

Add the possibility to import a value from the environment into kconfig
via the option syntax. Beside flexibility this has the advantage
providing proper dependencies.
Documented the options syntax.

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

8 files changed, 108 insertions, 35 deletions

diff --git a/scripts/kconfig/expr.h b/scripts/kconfig/expr.h
index b6f922c77e0b..9d4cba1c001d 100644
--- a/scripts/kconfig/expr.h
+++ b/scripts/kconfig/expr.h
@@ -106,7 +106,8 @@ struct symbol {
 #define SYMBOL_HASHMASK         0xff
 
 enum prop_type {
-        P_UNKNOWN, P_PROMPT, P_COMMENT, P_MENU, P_DEFAULT, P_CHOICE, P_SELECT, P_RANGE
+        P_UNKNOWN, P_PROMPT, P_COMMENT, P_MENU, P_DEFAULT, P_CHOICE,
+        P_SELECT, P_RANGE, P_ENV
 };
 
 struct property {
diff --git a/scripts/kconfig/lkc.h b/scripts/kconfig/lkc.h
index 8a07ee4f6bd4..4bc68f20a73c 100644
--- a/scripts/kconfig/lkc.h
+++ b/scripts/kconfig/lkc.h
@@ -44,6 +44,7 @@ extern "C" {
 
 #define T_OPT_MODULES           1
 #define T_OPT_DEFCONFIG_LIST    2
+#define T_OPT_ENV               3
 
 struct kconf_id {
         int name;
@@ -74,6 +75,7 @@ void kconfig_load(void);
 
 /* menu.c */
 void menu_init(void);
+void menu_warn(struct menu *menu, const char *fmt, ...);
 struct menu *menu_add_menu(void);
 void menu_end_menu(void);
 void menu_add_entry(struct symbol *sym);
@@ -103,6 +105,8 @@ void str_printf(struct gstr *gs, const char *fmt, ...);
 const char *str_get(struct gstr *gs);
 
 /* symbol.c */
+extern struct expr *sym_env_list;
+
 void sym_init(void);
 void sym_clear_all_valid(void);
 void sym_set_all_changed(void);
@@ -110,6 +114,7 @@ void sym_set_changed(struct symbol *sym);
 struct symbol *sym_check_deps(struct symbol *sym);
 struct property *prop_alloc(enum prop_type type, struct symbol *sym);
 struct symbol *prop_get_symbol(struct property *prop);
+struct property *sym_get_env_prop(struct symbol *sym);
 
 static inline tristate sym_get_tristate_value(struct symbol *sym)
 {
diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
index 3637d1057e13..e6ef171e5b14 100644
--- a/scripts/kconfig/menu.c
+++ b/scripts/kconfig/menu.c
@@ -15,7 +15,7 @@ static struct menu **last_entry_ptr;
 struct file *file_list;
 struct file *current_file;
 
-static void menu_warn(struct menu *menu, const char *fmt, ...)
+void menu_warn(struct menu *menu, const char *fmt, ...)
 {
         va_list ap;
         va_start(ap, fmt);
@@ -172,6 +172,9 @@ void menu_add_option(int token, char *arg)
                 else if (sym_defconfig_list != current_entry->sym)
                         zconf_error("trying to redefine defconfig symbol");
                 break;
+        case T_OPT_ENV:
+                prop_add_env(arg);
+                break;
         }
 }
 
diff --git a/scripts/kconfig/qconf.cc b/scripts/kconfig/qconf.cc
index 9fe27ca8a192..5d0fd38b089b 100644
--- a/scripts/kconfig/qconf.cc
+++ b/scripts/kconfig/qconf.cc
@@ -1088,7 +1088,11 @@ QString ConfigInfoView::debug_info(struct symbol *sym)
                         debug += "</a><br>";
                         break;
                 case P_DEFAULT:
-                        debug += "default: ";
+                case P_SELECT:
+                case P_RANGE:
+                case P_ENV:
+                        debug += prop_get_type_name(prop->type);
+                        debug += ": ";
                         expr_print(prop->expr, expr_print_help, &debug, E_NONE);
                         debug += "<br>";
                         break;
@@ -1099,16 +1103,6 @@ QString ConfigInfoView::debug_info(struct symbol *sym)
                                 debug += "<br>";
                         }
                         break;
-                case P_SELECT:
-                        debug += "select: ";
-                        expr_print(prop->expr, expr_print_help, &debug, E_NONE);
-                        debug += "<br>";
-                        break;
-                case P_RANGE:
-                        debug += "range: ";
-                        expr_print(prop->expr, expr_print_help, &debug, E_NONE);
-                        debug += "<br>";
-                        break;
                 default:
                         debug += "unknown property: ";
                         debug += prop_get_type_name(prop->type);
diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c
index a7dfc82fc858..99e3d02d1cfc 100644
--- a/scripts/kconfig/symbol.c
+++ b/scripts/kconfig/symbol.c
@@ -34,6 +34,8 @@ struct symbol *sym_defconfig_list;
 struct symbol *modules_sym;
 tristate modules_val;
 
+struct expr *sym_env_list;
+
 void sym_add_default(struct symbol *sym, const char *def)
 {
         struct property *prop = prop_alloc(P_DEFAULT, sym);
@@ -117,6 +119,15 @@ struct property *sym_get_choice_prop(struct symbol *sym)
         return NULL;
 }
 
+struct property *sym_get_env_prop(struct symbol *sym)
+{
+        struct property *prop;
+
+        for_all_properties(sym, prop, P_ENV)
+                return prop;
+        return NULL;
+}
+
 struct property *sym_get_default_prop(struct symbol *sym)
 {
         struct property *prop;
@@ -346,6 +357,9 @@ void sym_calc_value(struct symbol *sym)
                 ;
         }
 
+        if (sym->flags & SYMBOL_AUTO)
+                sym->flags &= ~SYMBOL_WRITE;
+
         sym->curr = newval;
         if (sym_is_choice(sym) && newval.tri == yes)
                 sym->curr.val = sym_calc_choice(sym);
@@ -860,6 +874,8 @@ const char *prop_get_type_name(enum prop_type type)
         switch (type) {
         case P_PROMPT:
                 return "prompt";
+        case P_ENV:
+                return "env";
         case P_COMMENT:
                 return "comment";
         case P_MENU:
@@ -877,3 +893,32 @@ const char *prop_get_type_name(enum prop_type type)
         }
         return "unknown";
 }
+
+void prop_add_env(const char *env)
+{
+        struct symbol *sym, *sym2;