[U-Boot] [PATCH v3 03/15] linux/kconfig.h: add CPP macros useful for per-image config options

Masahiro Yamada
2015-08-11T22:31:43Z

The previous commit introduced a useful macro used in makefiles,
in order to reference to different variables (CONFIG_... or
CONFIG_SPL_...) depending on the build context.

Per-image config option control is a PITA in C sources, too.
Here are some macros useful in C/CPP expressions.

CONFIG_IS_ENABLED(FOO) can be used as a shorthand for

(!defined(CONFIG_SPL_BUILD) && defined(CONFIG_FOO)) || \
(defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_FOO))

For example, it is useful to describe C code as follows,

#if CONFIG_IS_ENABLED(OF_CONTROL)
(device tree code)
#else
(board file code)
#endif

The ifdef conditional above is switched by CONFIG_OF_CONTROL during
the U-Boot proper building (CONFIG_SPL_BUILD is not defined), and by
CONFIG_SPL_OF_CONTROL during SPL building (CONFIG_SPL_BUILD is
defined).

The macro can be used in C context as well, so you can also write the
equivalent code as follows:

if (CONFIG_IS_ENABLED(OF_CONTROL)) {
(device tree code)
} else {
(board file code)
}

Another useful macro is CONFIG_VALUE().
CONFIG_VALUE(FOO) is expanded into CONFIG_FOO if CONFIG_SPL_BUILD is
undefined, and into CONFIG_SPL_FOO if CONFIG_SPL_BUILD is defined.

You can write as follows:

text_base = CONFIG_VALUE(TEXT_BASE);

instead of:

#ifdef CONFIG_SPL_BUILD
text_base = CONFIG_SPL_TEXT_BASE;
#else
text_base = CONFIG_TEXT_BASE;
#endif

This commit also adds slight hacking on fixdep so that it can
output a correct list of fixed dependencies.

If the fixdep finds CONFIG_IS_ENABLED(FOO) in a source file,
we want
$(wildcard include/config/foo.h)
in the U-boot proper building context, while we want
$(wildcard include/config/spl/foo.h)
in the SPL build context.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
---

Changes in v3: None
Changes in v2: None

include/linux/kconfig.h | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
scripts/basic/fixdep.c | 26 ++++++++++++++++++++++++++
2 files changed, 74 insertions(+)

diff --git a/include/linux/kconfig.h b/include/linux/kconfig.h
index be342b9..486fb94 100644
--- a/include/linux/kconfig.h
+++ b/include/linux/kconfig.h
@@ -43,4 +43,52 @@
*/
#define IS_MODULE(option) config_enabled(option##_MODULE)

+/*
+ * U-Boot add-on: Helper macros to reference to different macros
+ * (CONFIG_ or CONFIG_SPL_ prefixed), depending on the build context.
+ */
+#ifdef CONFIG_SPL_BUILD
+#define _IS_SPL 1
+#endif
+
+#define config_val(cfg) _config_val(_IS_SPL, cfg)
+#define _config_val(x, cfg) __config_val(x, cfg)
+#define __config_val(x, cfg) ___config_val(__ARG_PLACEHOLDER_##x, cfg)
+#define ___config_val(arg1_or_junk, cfg) \
+ ____config_val(arg1_or_junk CONFIG_SPL_##cfg, CONFIG_##cfg)
+#define ____config_val(__ignored, val, ...) val
+
+/*
+ * CONFIG_VAL(FOO) evaluates to the value of
+ * CONFIG_FOO if CONFIG_SPL_BUILD is undefined,
+ * CONFIG_SPL_FOO if CONFIG_SPL_BUILD is defined.
+ */
+#define CONFIG_VAL(option) config_val(option)
+
+/*
+ * CONFIG_IS_ENABLED(FOO) evaluates to
+ * 1 if CONFIG_SPL_BUILD is undefined and CONFIG_FOO is set to 'y' or 'm',
+ * 1 if CONFIG_SPL_BUILD is defined and CONFIG_SPL_FOO is set to 'y' or 'm',
+ * 0 otherwise.
+ */
+#define CONFIG_IS_ENABLED(option) \
+ (config_enabled(CONFIG_VAL(option)) || \
+ config_enabled(CONFIG_VAL(option##_MODULE)))
+
+/*
+ * CONFIG_IS_BUILTIN(FOO) evaluates to
+ * 1 if CONFIG_SPL_BUILD is undefined and CONFIG_FOO is set to 'y',
+ * 1 if CONFIG_SPL_BUILD is defined and CONFIG_SPL_FOO is set to 'y',
+ * 0 otherwise.
+ */
+#define CONFIG_IS_BUILTIN(option) config_enabled(CONFIG_VAL(option))
+
+/*
+ * CONFIG_IS_MODULE(FOO) evaluates to
+ * 1 if CONFIG_SPL_BUILD is undefined and CONFIG_FOO is set to 'm',
+ * 1 if CONFIG_SPL_BUILD is defined and CONFIG_SPL_FOO is set to 'm',
+ * 0 otherwise.
+ */
+#define CONFIG_IS_MODULE(option) config_enabled(CONFIG_VAL(option##_MODULE))
+
#endif /* __LINUX_KCONFIG_H */
diff --git a/scripts/basic/fixdep.c b/scripts/basic/fixdep.c
index 46cc1b3..20fed03 100644
--- a/scripts/basic/fixdep.c
+++ b/scripts/basic/fixdep.c
@@ -123,6 +123,7 @@
char *target;
char *depfile;
char *cmdline;
+int is_spl_build = 0; /* hack for U-boot */

static void usage(void)
{
@@ -239,6 +240,7 @@ static void parse_config_file(const char *map, size_t len)
/* start at +1, so that p can never be < map */
const int *m = (const int *) map + 1;
const char *p, *q;
+ char tmp_buf[256] = "SPL_"; /* hack for U-Boot */

for (; m < end; m++) {
if (*m == INT_CONF) { p = (char *) m ; goto conf; }
@@ -263,6 +265,26 @@ static void parse_config_file(const char *map, size_t len)
q -= 7;
if (q - p < 0)
continue;
+
+ /* U-Boot also handles CONFIG_IS_{ENABLED/BUILTIN/MODULE} */
+ if ((q - p == 10 && !memcmp(p, "IS_ENABLED(", 11)) ||
+ (q - p == 10 && !memcmp(p, "IS_BUILTIN(", 11)) ||
+ (q - p == 9 && !memcmp(p, "IS_MODULE(", 10))) {
+ p = q + 1;
+ for (q = p; q < map + len; q++)
+ if (*q == ')')
+ goto found2;
+ continue;
+
+ found2:
+ if (is_spl_build) {
+ memcpy(tmp_buf + 4, p, q - p);
+ q = tmp_buf + 4 + (q - p);
+ p = tmp_buf;
+ }
+ }
+ /* end U-Boot hack */
+
use_config(p, q - p);
}
}
@@ -456,6 +478,10 @@ int main(int argc, char *argv[])
target = argv[2];
cmdline = argv[3];

+ /* hack for U-boot */
+ if (!strncmp(target, "spl/", 4) || !strncmp(target, "tpl/", 4))
+ is_spl_build = 1;
+
print_cmdline();
print_deps();

--
1.9.1