6lowpan: add debugfs support

This patch will introduce a 6lowpan entry into the debugfs if enabled.
Inside this 6lowpan directory we create a subdirectories of all 6lowpan
interfaces to offer a per interface debugfs support.

Reviewed-by: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

5 files changed, 117 insertions, 1 deletions

diff --git a/net/6lowpan/6lowpan_i.h b/net/6lowpan/6lowpan_i.h
new file mode 100644
index 000000000000..d16bb4b14aa1
--- /dev/null
+++ b/net/6lowpan/6lowpan_i.h
@@ -0,0 +1,28 @@
+#ifndef __6LOWPAN_I_H
+#define __6LOWPAN_I_H
+
+#include <linux/netdevice.h>
+
+#ifdef CONFIG_6LOWPAN_DEBUGFS
+int lowpan_dev_debugfs_init(struct net_device *dev);
+void lowpan_dev_debugfs_exit(struct net_device *dev);
+
+int __init lowpan_debugfs_init(void);
+void lowpan_debugfs_exit(void);
+#else
+static inline int lowpan_dev_debugfs_init(struct net_device *dev)
+{
+        return 0;
+}
+
+static inline void lowpan_dev_debugfs_exit(struct net_device *dev) { }
+
+static inline int __init lowpan_debugfs_init(void)
+{
+        return 0;
+}
+
+static inline void lowpan_debugfs_exit(void) { }
+#endif /* CONFIG_6LOWPAN_DEBUGFS */
+
+#endif /* __6LOWPAN_I_H */
diff --git a/net/6lowpan/Kconfig b/net/6lowpan/Kconfig
index bcb9d8a21fc0..9c051512d14f 100644
--- a/net/6lowpan/Kconfig
+++ b/net/6lowpan/Kconfig
@@ -5,6 +5,14 @@ menuconfig 6LOWPAN
           This enables IPv6 over Low power Wireless Personal Area Network -
           "6LoWPAN" which is supported by IEEE 802.15.4 or Bluetooth stacks.
 
+config 6LOWPAN_DEBUGFS
+        bool "6LoWPAN debugfs support"
+        depends on 6LOWPAN
+        depends on DEBUG_FS
+        ---help---
+          This enables 6LoWPAN debugfs support. For example to manipulate
+          IPHC context information at runtime.
+
 menuconfig 6LOWPAN_NHC
         tristate "Next Header and Generic Header Compression Support"
         depends on 6LOWPAN
diff --git a/net/6lowpan/Makefile b/net/6lowpan/Makefile
index 9e35a5d7b92d..e44f3bf2dd42 100644
--- a/net/6lowpan/Makefile
+++ b/net/6lowpan/Makefile
@@ -1,6 +1,7 @@
 obj-$(CONFIG_6LOWPAN) += 6lowpan.o
 
 6lowpan-y := core.o iphc.o nhc.o
+6lowpan-$(CONFIG_6LOWPAN_DEBUGFS) += debugfs.o
 
 #rfc6282 nhcs
 obj-$(CONFIG_6LOWPAN_NHC_DEST) += nhc_dest.o
diff --git a/net/6lowpan/core.c b/net/6lowpan/core.c
index 80fc50987cf3..c7f06f5c0121 100644
--- a/net/6lowpan/core.c
+++ b/net/6lowpan/core.c
@@ -15,9 +15,13 @@
 
 #include <net/6lowpan.h>
 
+#include "6lowpan_i.h"
+
 int lowpan_register_netdevice(struct net_device *dev,
                               enum lowpan_lltypes lltype)
 {
+        int ret;
+
         dev->addr_len = EUI64_ADDR_LEN;
         dev->type = ARPHRD_6LOWPAN;
         dev->mtu = IPV6_MIN_MTU;
@@ -25,7 +29,15 @@ int lowpan_register_netdevice(struct net_device *dev,
 
         lowpan_priv(dev)->lltype = lltype;
 
-        return register_netdevice(dev);
+        ret = lowpan_dev_debugfs_init(dev);
+        if (ret < 0)
+                return ret;
+
+        ret = register_netdevice(dev);
+        if (ret < 0)
+                lowpan_dev_debugfs_exit(dev);
+
+        return ret;
 }
 EXPORT_SYMBOL(lowpan_register_netdevice);
 
@@ -44,6 +56,7 @@ EXPORT_SYMBOL(lowpan_register_netdev);
 void lowpan_unregister_netdevice(struct net_device *dev)
 {
         unregister_netdevice(dev);
+        lowpan_dev_debugfs_exit(dev);
 }
 EXPORT_SYMBOL(lowpan_unregister_netdevice);
 
@@ -57,6 +70,12 @@ EXPORT_SYMBOL(lowpan_unregister_netdev);
 
 static int __init lowpan_module_init(void)
 {
+        int ret;
+
+        ret = lowpan_debugfs_init();
+        if (ret < 0)
+                return ret;
+
         request_module_nowait("ipv6");
 
         request_module_nowait("nhc_dest");
@@ -69,6 +88,13 @@ static int __init lowpan_module_init(void)
 
         return 0;
 }
+
+static void __exit lowpan_module_exit(void)
+{
+        lowpan_debugfs_exit();
+}
+
 module_init(lowpan_module_init);
+module_exit(lowpan_module_exit);
 
 MODULE_LICENSE("GPL");
diff --git a/net/6lowpan/debugfs.c b/net/6lowpan/debugfs.c
new file mode 100644
index 000000000000..88eef84df0fc
--- /dev/null
+++ b/net/6lowpan/debugfs.c
@@ -0,0 +1,53 @@
+/* This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Authors:
+ * (C) 2015 Pengutronix, Alexander Aring <aar@pengutronix.de>
+ * Copyright (c)  2015 Nordic Semiconductor. All Rights Reserved.
+ */
+
+#include <net/6lowpan.h>
+
+#include "6lowpan_i.h"
+
+static struct dentry *lowpan_debugfs;
+
+int lowpan_dev_debugfs_init(struct net_device *dev)
+{
+        struct lowpan_priv *lpriv = lowpan_priv(dev);
+
+        /* creating the root */
+        lpriv->iface_debugfs = debugfs_create_dir(dev->name, lowpan_debugfs);
+        if (!lpriv->iface_debugfs)
+                goto fail;
+
+        return 0;
+
+fail:
+        return -EINVAL;
+}
+
+void lowpan_dev_debugfs_exit(struct net_device *dev)
+{
+        debugfs_remove_recursive(lowpan_priv(dev)->iface_debugfs);
+}
+
+int __init lowpan_debugfs_init(void)
+{
+        lowpan_debugfs = debugfs_create_dir("6lowpan", NULL);
+        if (!lowpan_debugfs)
+                return -EINVAL;
+
+        return 0;
+}
+
+void lowpan_debugfs_exit(void)
+{
+        debugfs_remove_recursive(lowpan_debugfs);
+}