Merge branch 'for-next/nvdevvars'

4 files changed, 154 insertions, 24 deletions

diff --git a/Documentation/user/variables.rst b/Documentation/user/variables.rst
index 0abc25d98a..89aadf58fd 100644
--- a/Documentation/user/variables.rst
+++ b/Documentation/user/variables.rst
@@ -66,6 +66,24 @@ examples:
     model: myboard
   barebox@yourboard:/
 
+Non volatile device variables
+-----------------------------
+
+Non volatile device variables are used to make device parameters persistent. They
+are regular nv variables but are linked with other devices instead of the global
+device. Every nv variable in the form nv.dev.<devname>.<paramname> will be mirrored
+to the corresponding <devname>.<paramname> variable.
+
+This example changes the partitioning of the nand0 device:
+
+.. code-block:: sh
+  barebox@Phytec phyCARD-i.MX27:/ nv dev.nand0.partitions: 4M(barebox),1M(barebox-environment),-(root)
+  barebox@Phytec phyCARD-i.MX27:/ devinfo nand0
+    Parameters:
+    [...]
+    partitions: 4M(barebox),1M(barebox-environment),8M(kernel),1011M(root)
+    [...]
+
 .. _magicvars:
 
 Magic variables
diff --git a/common/globalvar.c b/common/globalvar.c
index 75e4d43afb..c0958e11ea 100644
--- a/common/globalvar.c
+++ b/common/globalvar.c
@@ -68,22 +68,115 @@ static int nv_save(const char *name, const char *val)
 	return 0;
 }
 
+/**
+ * dev_param_init_from_nv - initialize a device parameter from nv variable
+ * @dev: The device
+ * @name: The parameter name
+ *
+ * This function initializes a newly created device parameter from the corresponding
+ * nv.dev.<devname>.<paramname> variable.
+ */
+void dev_param_init_from_nv(struct device_d *dev, const char *name)
+{
+	char *nvname;
+	const char *val;
+	int ret = 0;
+
+	if (dev == &nv_device)
+		return;
+	if (dev == &global_device)
+		return;
+
+	nvname = basprintf("dev.%s.%s", dev_name(dev), name);
+	val = dev_get_param(&nv_device, nvname);
+	if (val) {
+		ret = dev_set_param(dev, name, val);
+		if (ret)
+			pr_err("Cannot init param from nv: %s.%s=%s: %s\n",
+				dev_name(dev), name, val, strerror(-ret));
+	}
+
+	free(nvname);
+}
+
+/**
+ * nvvar_device_dispatch - dispatch dev.<dev>.<param> name into device and parameter name
+ * @name: The incoming name in the form dev.<dev>.<param>
+ * @dev: The returned device_d * belonging to <dev>
+ * @pname: the parameter name
+ *
+ * Given a dev.<dev>.<param> string this function finds the device_d * belonging to
+ * <dev> and the parameter name from <param>.
+ *
+ * Return: When incoming string does not belong to the device namespace (does not begin
+ * with "dev." this function returns 0. A value > 0 is returned when the incoming string
+ * is in the device namespace and the string can be dispatched into a device_d * and a
+ * parameter name. A negative error code is returned when the incoming string belongs to
+ * the device namespace, but cannot be dispatched.
+ */
+static int nvvar_device_dispatch(const char *name, struct device_d **dev,
+				 const char **pname)
+{
+	char *devname;
+	const char *dot;
+	int dotpos;
+
+	*dev = NULL;
+
+	if (strncmp(name, "dev.", 4))
+		return 0;
+
+	name += 4;
+
+	dot = strchr(name, '.');
+	if (!dot)
+		return -EINVAL;
+
+	dotpos = dot - name;
+
+	devname = xstrndup(name, dotpos);
+	*dev = get_device_by_name(devname);
+	free(devname);
+
+	if (*dev == &nv_device || *dev == &global_device)
+		return -EINVAL;
+
+	*pname = dot + 1;
+
+	return 1;
+}
+
 static int nv_set(struct device_d *dev, struct param_d *p, const char *val)
 {
-	struct param_d *gp;
 	int ret;
+	int devspace;
+	struct device_d *rdev;
+	const char *pname;
 
 	if (!val)
 		val = "";
 
-	gp = get_param_by_name(&global_device, p->name);
-	if (!gp)
-		return -EINVAL;
-
-	ret = gp->set(&global_device, gp, val);
-	if (ret)
+	ret = nvvar_device_dispatch(p->name, &rdev, &pname);
+	if (ret < 0)
 		return ret;
 
+	devspace = ret;
+
+	if (devspace) {
+		if (rdev) {
+			ret = dev_set_param(rdev, pname, val);
+			if (ret) {
+				pr_err("Cannot init param from nv: %s.%s=%s: %s\n",
+					dev_name(rdev), pname, val, strerror(-ret));
+				return ret;
+			}
+		}
+	} else {
+		ret = dev_set_param(&global_device, p->name, val);
+		if (ret)
+			return ret;
+	}
+
 	free(p->value);
 	p->value = xstrdup(val);
 
@@ -99,15 +192,26 @@ int nvvar_add(const char *name, const char *value)
 {
 	struct param_d *p, *gp;
 	int ret;
+	int devspace;
+	struct device_d *dev;
+	const char *pname;
 
 	if (!IS_ENABLED(CONFIG_NVVAR))
 		return -ENOSYS;
 
+	ret = nvvar_device_dispatch(name, &dev, &pname);
+	if (ret < 0)
+		return ret;
+
+	devspace = ret;
+
 	gp = get_param_by_name(&nv_device, name);
 	if (gp) {
-		ret = dev_set_param(&global_device, name, value);
-		if (ret)
-			return ret;
+		if (!devspace) {
+			ret = dev_set_param(&global_device, name, value);
+			if (ret)
+				return ret;
+		}
 
 		ret = dev_set_param(&nv_device, name, value);
 		if (ret)
@@ -116,27 +220,26 @@ int nvvar_add(const char *name, const char *value)
 		return 0;
 	}
 
-	ret = globalvar_add_simple(name, value);
-	if (ret && ret != -EEXIST)
-		return ret;
+	if (!devspace) {
+		ret = globalvar_add_simple(name, value);
+		if (ret && ret != -EEXIST)
+			return ret;
+	}
 
 	p = dev_add_param(&nv_device, name, nv_set, nv_get, 0);
 	if (IS_ERR(p))
 		return PTR_ERR(p);
 
-	if (value) {
-		ret = dev_set_param(&global_device, name, value);
-		if (ret)
-			return ret;
-	} else {
-		value = dev_get_param(&global_device, name);
-		if (!value)
-			value = "";
+	if (!value) {
+		if (devspace) {
+			if (dev)
+				value = dev_get_param(dev, pname);
+		} else {
+			value = dev_get_param(&global_device, name);
+		}
 	}
 
-	p->value = xstrdup(value);
-
-	return nv_save(p->name, value);
+	return nv_set(&nv_device, p, value);
 }
 
 int nvvar_remove(const char *name)
diff --git a/include/globalvar.h b/include/globalvar.h
index 5dfa371409..67b97de486 100644
--- a/include/globalvar.h
+++ b/include/globalvar.h
@@ -94,6 +94,8 @@ int nvvar_add(const char *name, const char *value);
 int nvvar_remove(const char *name);
 void globalvar_print(void);
 
+void dev_param_init_from_nv(struct device_d *dev, const char *name);
+
 #else
 static inline int globalvar_add_simple(const char *name, const char *value)
 {
@@ -165,6 +167,10 @@ static inline int nvvar_remove(const char *name)
 	return 0;
 }
 
+static inline void dev_param_init_from_nv(struct device_d *dev, const char *name)
+{
+}
+
 #endif
 
 #endif /* __GLOBALVAR_H */
diff --git a/lib/parameter.c b/lib/parameter.c
index 3d356fb972..656a6037c6 100644
--- a/lib/parameter.c
+++ b/lib/parameter.c
@@ -28,6 +28,7 @@
 #include <malloc.h>
 #include <driver.h>
 #include <string.h>
+#include <globalvar.h>
 #include <linux/err.h>
 
 struct param_d *get_param_by_name(struct device_d *dev, const char *name)
@@ -156,6 +157,8 @@ static int __dev_add_param(struct param_d *param, struct device_d *dev, const ch
 	param->dev = dev;
 	list_add_sort(&param->list, &dev->parameters, compare);
 
+	dev_param_init_from_nv(dev, name);
+
 	return 0;
 }