Kconfig: Create Kconfig symbol for NVVAR

nvvar support not only needs globalvar, but also persistent
environment storage. Add a separate default-y option which
depends on ENV_HANDLING for this case. Make the option visible
to let the user decide whether he wants to have this option
and add a help text to make this decision easier.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

3 files changed, 32 insertions, 3 deletions

diff --git a/commands/Kconfig b/commands/Kconfig
index 56b95425c0..0aab6effea 100644
--- a/commands/Kconfig
+++ b/commands/Kconfig
@@ -715,7 +715,7 @@ endmenu
 menu "Environment"
 
 config CMD_NV
-	select GLOBALVAR
+	depends on NVVAR
 	tristate
 	prompt "nv"
 	help
diff --git a/common/Kconfig b/common/Kconfig
index a37141e3c7..fdf2f0da13 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -161,6 +161,21 @@ config GLOBALVAR
 	  variables are used to control several aspects of the system behaviour.
 	  If unsure, say yes here.
 
+config NVVAR
+	bool "Non volatile global environment variables support"
+	default y if !SHELL_NONE
+	depends on GLOBALVAR
+	depends on ENV_HANDLING
+	help
+	  Non volatile environment variables begin with "nv.". They behave like
+	  global variables above, but their values are saved in the environment
+	  storage with 'saveenv' and thus are persistent over restarts. nv variables
+	  are coupled with global variables of the same name. Setting "nv.foo" results
+	  in "global.foo" changed also (but not the other way round: setting "global.foo"
+	  leaves "nv.foo" untouched). The idea is that nv variables can store defaults
+	  while global variables can be changed during runtime without changing the
+	  default.
+
 menu "memory layout"
 
 source "pbl/Kconfig"
diff --git a/common/globalvar.c b/common/globalvar.c
index 9a793ac4a9..a777c14283 100644
--- a/common/globalvar.c
+++ b/common/globalvar.c
@@ -90,6 +90,9 @@ int nvvar_add(const char *name, const char *value)
 	struct param_d *p, *gp;
 	int ret;
 
+	if (!IS_ENABLED(CONFIG_NVVAR))
+		return -ENOSYS;
+
 	gp = get_param_by_name(&nv_device, name);
 	if (gp) {
 		ret = dev_set_param(&global_device, name, value);
@@ -131,6 +134,9 @@ int nvvar_remove(const char *name)
 	struct param_d *p;
 	char *fname;
 
+	if (!IS_ENABLED(CONFIG_NVVAR))
+		return -ENOSYS;
+
 	p = get_param_by_name(&nv_device, name);
 	if (!p)
 		return -ENOENT;
@@ -153,6 +159,9 @@ int nvvar_load(void)
 	DIR *dir;
 	struct dirent *d;
 
+	if (!IS_ENABLED(CONFIG_NVVAR))
+		return -ENOSYS;
+
 	dir = opendir("/env/nv");
 	if (!dir)
 		return -ENOENT;
@@ -185,7 +194,7 @@ static void device_param_print(struct device_d *dev)
 		const char *p = dev_get_param(dev, param->name);
 		const char *nv = NULL;
 
-		if (dev != &nv_device)
+		if (IS_ENABLED(CONFIG_NVVAR) && dev != &nv_device)
 			nv = dev_get_param(&nv_device, param->name);
 
 		printf("%s%s: %s\n", nv ? "* " : "  ", param->name, p);
@@ -194,6 +203,9 @@ static void device_param_print(struct device_d *dev)
 
 void nvvar_print(void)
 {
+	if (!IS_ENABLED(CONFIG_NVVAR))
+		return;
+
 	device_param_print(&nv_device);
 }
 
@@ -264,7 +276,9 @@ int globalvar_add_simple(const char *name, const char *value)
 static int globalvar_init(void)
 {
 	register_device(&global_device);
-	register_device(&nv_device);
+
+	if (IS_ENABLED(CONFIG_NVVAR))
+		register_device(&nv_device);
 
 	globalvar_add_simple("version", UTS_RELEASE);