net/dsa/tag_xrs700x.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * XRS700x tag format handling
   4  * Copyright (c) 2008-2009 Marvell Semiconductor
   5  * Copyright (c) 2020 NovaTech LLC
   6  */
   7
   8 #include <linux/bitops.h>
   9
  10 #include "tag.h"
  11
  12 #define XRS700X_NAME "xrs700x"
  13
  14 static struct sk_buff *xrs700x_xmit(struct sk_buff *skb, struct net_device *dev)
  15 {
  16         struct dsa_port *partner, *dp = dsa_user_to_port(dev);
  17         u8 *trailer;
  18
  19         trailer = skb_put(skb, 1);
  20         trailer[0] = BIT(dp->index);
  21
  22         if (dp->hsr_dev)
  23                 dsa_hsr_foreach_port(partner, dp->ds, dp->hsr_dev)
  24                         if (partner != dp)
  25                                 trailer[0] |= BIT(partner->index);
  26
  27         return skb;
  28 }
  29
  30 static struct sk_buff *xrs700x_rcv(struct sk_buff *skb, struct net_device *dev)
  31 {
  32         int source_port;
  33         u8 *trailer;
  34
  35         trailer = skb_tail_pointer(skb) - 1;
  36
  37         source_port = ffs((int)trailer[0]) - 1;
  38
  39         if (source_port < 0)
  40                 return NULL;
  41
  42         skb->dev = dsa_conduit_find_user(dev, 0, source_port);
  43         if (!skb->dev)
  44                 return NULL;
  45
  46         if (pskb_trim_rcsum(skb, skb->len - 1))
  47                 return NULL;
  48
  49         /* Frame is forwarded by hardware, don't forward in software. */
  50         dsa_default_offload_fwd_mark(skb);
  51
  52         return skb;
  53 }
  54
  55 static const struct dsa_device_ops xrs700x_netdev_ops = {
  56         .name   = XRS700X_NAME,
  57         .proto  = DSA_TAG_PROTO_XRS700X,
  58         .xmit   = xrs700x_xmit,
  59         .rcv    = xrs700x_rcv,
  60         .needed_tailroom = 1,
  61 };
  62
  63 MODULE_DESCRIPTION("DSA tag driver for XRS700x switches");
  64 MODULE_LICENSE("GPL");
  65 MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_XRS700X, XRS700X_NAME);
  66
  67 module_dsa_tag_driver(xrs700x_netdev_ops);