docs: networking: convert 6lowpan.txt to ReST

- add SPDX header;
- use document title markup;
- mark code blocks and literals as such;
- adjust identation, whitespaces and blank lines;
- add to networking/index.rst.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Stefan Schmidt <stefan@datenfreihafen.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 53 insertions, 0 deletions

diff --git a/Documentation/networking/6lowpan.rst b/Documentation/networking/6lowpan.rst
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index 000000000000..e70a6520cc33
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+++ b/Documentation/networking/6lowpan.rst
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+.. SPDX-License-Identifier: GPL-2.0
+
+==============================================
+Netdev private dataroom for 6lowpan interfaces
+==============================================
+
+All 6lowpan able net devices, means all interfaces with ARPHRD_6LOWPAN,
+must have "struct lowpan_priv" placed at beginning of netdev_priv.
+
+The priv_size of each interface should be calculate by::
+
+ dev->priv_size = LOWPAN_PRIV_SIZE(LL_6LOWPAN_PRIV_DATA);
+
+Where LL_PRIV_6LOWPAN_DATA is sizeof linklayer 6lowpan private data struct.
+To access the LL_PRIV_6LOWPAN_DATA structure you can cast::
+
+ lowpan_priv(dev)-priv;
+
+to your LL_6LOWPAN_PRIV_DATA structure.
+
+Before registering the lowpan netdev interface you must run::
+
+ lowpan_netdev_setup(dev, LOWPAN_LLTYPE_FOOBAR);
+
+wheres LOWPAN_LLTYPE_FOOBAR is a define for your 6LoWPAN linklayer type of
+enum lowpan_lltypes.
+
+Example to evaluate the private usually you can do::
+
+ static inline struct lowpan_priv_foobar *
+ lowpan_foobar_priv(struct net_device *dev)
+ {
+	return (struct lowpan_priv_foobar *)lowpan_priv(dev)->priv;
+ }
+
+ switch (dev->type) {
+ case ARPHRD_6LOWPAN:
+	lowpan_priv = lowpan_priv(dev);
+	/* do great stuff which is ARPHRD_6LOWPAN related */
+	switch (lowpan_priv->lltype) {
+	case LOWPAN_LLTYPE_FOOBAR:
+		/* do 802.15.4 6LoWPAN handling here */
+		lowpan_foobar_priv(dev)->bar = foo;
+		break;
+	...
+	}
+	break;
+ ...
+ }
+
+In case of generic 6lowpan branch ("net/6lowpan") you can remove the check
+on ARPHRD_6LOWPAN, because you can be sure that these function are called
+by ARPHRD_6LOWPAN interfaces.