kconfig: Document the 'symbol' struct
Visibility and choices in particular might be a bit tricky to figure
out.
Also fix existing comment to point out that P_MENU is also used for
menus.
Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/scripts/kconfig/expr.h b/scripts/kconfig/expr.h
index ae7583c..e7d7a5e 100644
--- a/scripts/kconfig/expr.h
+++ b/scripts/kconfig/expr.h
@@ -74,17 +74,60 @@ enum {
S_DEF_COUNT
};
+/*
+ * Represents a configuration symbol.
+ *
+ * Choices are represented as a special kind of symbol and have the
+ * SYMBOL_CHOICE bit set in 'flags'.
+ */
struct symbol {
+ /* The next symbol in the same bucket in the symbol hash table */
struct symbol *next;
+
+ /* The name of the symbol, e.g. "FOO" for 'config FOO' */
char *name;
+
+ /* S_BOOLEAN, S_TRISTATE, ... */
enum symbol_type type;
+
+ /*
+ * The calculated value of the symbol. The SYMBOL_VALID bit is set in
+ * 'flags' when this is up to date. Note that this value might differ
+ * from the user value set in e.g. a .config file, due to visibility.
+ */
struct symbol_value curr;
+
+ /*
+ * Values for the symbol provided from outside. def[S_DEF_USER] holds
+ * the .config value.
+ */
struct symbol_value def[S_DEF_COUNT];
+
+ /*
+ * An upper bound on the tristate value the user can set for the symbol
+ * if it is a boolean or tristate. Calculated from prompt dependencies,
+ * which also inherit dependencies from enclosing menus, choices, and
+ * ifs. If 'n', the user value will be ignored.
+ *
+ * Symbols lacking prompts always have visibility 'n'.
+ */
tristate visible;
+
+ /* SYMBOL_* flags */
int flags;
+
+ /* List of properties. See prop_type. */
struct property *prop;
+
+ /* Dependencies from enclosing menus, choices, and ifs */
struct expr_value dir_dep;
+
+ /* Reverse dependencies through being selected by other symbols */
struct expr_value rev_dep;
+
+ /*
+ * "Weak" reverse dependencies through being implied by other symbols
+ */
struct expr_value implied;
};
@@ -133,7 +176,7 @@ enum prop_type {
P_UNKNOWN,
P_PROMPT, /* prompt "foo prompt" or "BAZ Value" */
P_COMMENT, /* text associated with a comment */
- P_MENU, /* prompt associated with a menuconfig option */
+ P_MENU, /* prompt associated with a menu or menuconfig symbol */
P_DEFAULT, /* default y */
P_CHOICE, /* choice value */
P_SELECT, /* select BAR */