[PATCH v2 2/2] env/sf.c: honour CONFIG_SPL_SAVEENV

Rasmus Villemoes rasmus.villemoes at prevas.dk
Fri Mar 27 00:02:00 CET 2020

Deciding whether to compile the env_sf_save() function based solely on
CONFIG_SPL_BUILD is wrong: For U-Boot proper, it leads to a build
warning in case CONFIG_CMD_SAVEENV=n (because the initialization of
the .save member is guarded by CONFIG_CMD_SAVEENV, while the
env_sf_save() function is built if !CONFIG_SPL_BUILD - and even
without the CONFIG_CMD_SAVEENV guard, the env_save_ptr() macro would
just expand to NULL, with no reference to env_sf_save visible to the
compiler). And for SPL, when one selects CONFIG_SPL_SAVEENV, one
obviously expects to actually be able to save the environment.

The compiler warning can be fixed by using a "<something> ?
env_sf_save : NULL" construction instead of a macro that just eats its
argument and expands to NULL. That way, if <something> is false,
env_sf_save gets eliminated as dead code, but the compiler still sees
the reference to it.

For <something>, we can use CONFIG_IS_ENABLED(SAVEENV), which is true

- For U-Boot proper, when CONFIG_CMD_SAVEENV is set (because
  CONFIG_SAVEENV is a hidden config symbol that gets set if and only
  if CONFIG_CMD_SAVEENV is set).
- For SPL, when CONFIG_SPL_SAVEENV is set.

As a bonus, this also removes quite a few preprocessor conditionals.

This has been run-time tested on a mpc8309-derived board to verify
that saving the environment does indeed work in SPL with these patches

Signed-off-by: Rasmus Villemoes <rasmus.villemoes at prevas.dk>
v2: Use 'CONFIG_IS_ENABLED(SAVEENV) ? env_sf_save : NULL' directly
instead of the dropped ENV_SAVE_PTR macro and expand commit message a

 env/sf.c | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/env/sf.c b/env/sf.c
index 5ef4055219..f41a846294 100644
--- a/env/sf.c
+++ b/env/sf.c
@@ -21,16 +21,12 @@
 #include <u-boot/crc.h>
-#define CMD_SAVEENV
 #define INITENV
 static ulong env_offset		= CONFIG_ENV_OFFSET;
 static ulong env_new_offset	= CONFIG_ENV_OFFSET_REDUND;
@@ -69,7 +65,6 @@ static int setup_flash_device(void)
 static int env_sf_save(void)
 	env_t	env_new;
@@ -148,7 +143,6 @@ static int env_sf_save(void)
 	return ret;
-#endif /* CMD_SAVEENV */
 static int env_sf_load(void)
@@ -187,7 +181,6 @@ out:
 	return ret;
 static int env_sf_save(void)
 	u32	saved_size, saved_offset, sector;
@@ -247,7 +240,6 @@ static int env_sf_save(void)
 	return ret;
-#endif /* CMD_SAVEENV */
 static int env_sf_load(void)
@@ -313,9 +305,7 @@ U_BOOT_ENV_LOCATION(sf) = {
 	.location	= ENVL_SPI_FLASH,
 	ENV_NAME("SPI Flash")
 	.load		= env_sf_load,
-	.save		= env_save_ptr(env_sf_save),
+	.save		= CONFIG_IS_ENABLED(SAVEENV) ? env_sf_save : NULL,
 #if defined(INITENV) && (CONFIG_ENV_ADDR != 0x0)
 	.init		= env_sf_init,

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