[PATCH] powerpc: Add support for changing properties from userspace

Add support to reconfigure the device tree through the existing
proc filesystem interface.  Add "add_property", "remove_property",
and "update_property" commands to the existing interface.

Signed-off-by: Dave Boutcher <sleddog@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 100 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/pseries/reconfig.c b/arch/powerpc/platforms/pseries/reconfig.c
index d8864164dbe8..86cfa6ecdcf3 100644
--- a/arch/powerpc/platforms/pseries/reconfig.c
+++ b/arch/powerpc/platforms/pseries/reconfig.c
@@ -350,6 +350,100 @@ static int do_remove_node(char *buf)
         return rv;
 }
 
+static char *parse_node(char *buf, size_t bufsize, struct device_node **npp)
+{
+        char *handle_str;
+        phandle handle;
+        *npp = NULL;
+
+        handle_str = buf;
+
+        buf = strchr(buf, ' ');
+        if (!buf)
+                return NULL;
+        *buf = '\0';
+        buf++;
+
+        handle = simple_strtoul(handle_str, NULL, 10);
+
+        *npp = of_find_node_by_phandle(handle);
+        return buf;
+}
+
+static int do_add_property(char *buf, size_t bufsize)
+{
+        struct property *prop = NULL;
+        struct device_node *np;
+        unsigned char *value;
+        char *name, *end;
+        int length;
+        end = buf + bufsize;
+        buf = parse_node(buf, bufsize, &np);
+
+        if (!np)
+                return -ENODEV;
+
+        if (parse_next_property(buf, end, &name, &length, &value) == NULL)
+                return -EINVAL;
+
+        prop = new_property(name, length, value, NULL);
+        if (!prop)
+                return -ENOMEM;
+
+        prom_add_property(np, prop);
+
+        return 0;
+}
+
+static int do_remove_property(char *buf, size_t bufsize)
+{
+        struct device_node *np;
+        char *tmp;
+        struct property *prop;
+        buf = parse_node(buf, bufsize, &np);
+
+        if (!np)
+                return -ENODEV;
+
+        tmp = strchr(buf,' ');
+        if (tmp)
+                *tmp = '\0';
+
+        if (strlen(buf) == 0)
+                return -EINVAL;
+
+        prop = of_find_property(np, buf, NULL);
+
+        return prom_remove_property(np, prop);
+}
+
+static int do_update_property(char *buf, size_t bufsize)
+{
+        struct device_node *np;
+        unsigned char *value;
+        char *name, *end;
+        int length;
+        struct property *newprop, *oldprop;
+        buf = parse_node(buf, bufsize, &np);
+        end = buf + bufsize;
+
+        if (!np)
+                return -ENODEV;
+
+        if (parse_next_property(buf, end, &name, &length, &value) == NULL)
+                return -EINVAL;
+
+        newprop = new_property(name, length, value, NULL);
+        if (!newprop)
+                return -ENOMEM;
+
+        oldprop = of_find_property(np, name,NULL);
+        if (!oldprop)
+                return -ENODEV;
+
+        return prom_update_property(np, newprop, oldprop);
+}
+
 /**
  * ofdt_write - perform operations on the Open Firmware device tree
  *
@@ -392,6 +486,12 @@ static ssize_t ofdt_write(struct file *file, const char __user *buf, size_t coun
                 rv = do_add_node(tmp, count - (tmp - kbuf));
         else if (!strcmp(kbuf, "remove_node"))
                 rv = do_remove_node(tmp);
+        else if (!strcmp(kbuf, "add_property"))
+                rv = do_add_property(tmp, count - (tmp - kbuf));
+        else if (!strcmp(kbuf, "remove_property"))
+                rv = do_remove_property(tmp, count - (tmp - kbuf));
+        else if (!strcmp(kbuf, "update_property"))
+                rv = do_update_property(tmp, count - (tmp - kbuf));
         else
                 rv = -EINVAL;
 out: