target/linux/ipq40xx/patches-6.1/701-net-dsa-add-out-of-band-tagging-protocol.patch

   1 From a32e16b3c2fc1954ad6e09737439f60e5890278e Mon Sep 17 00:00:00 2001
   2 From: Maxime Chevallier <maxime.chevallier@bootlin.com>
   3 Date: Fri, 4 Nov 2022 18:41:49 +0100
   4 Subject: [PATCH] net: dsa: add out-of-band tagging protocol
   5
   6 This tagging protocol is designed for the situation where the link
   7 between the MAC and the Switch is designed such that the Destination
   8 Port, which is usually embedded in some part of the Ethernet Header, is
   9 sent out-of-band, and isn't present at all in the Ethernet frame.
  10
  11 This can happen when the MAC and Switch are tightly integrated on an
  12 SoC, as is the case with the Qualcomm IPQ4019 for example, where the DSA
  13 tag is inserted directly into the DMA descriptors. In that case,
  14 the MAC driver is responsible for sending the tag to the switch using
  15 the out-of-band medium. To do so, the MAC driver needs to have the
  16 information of the destination port for that skb.
  17
  18 Add a new tagging protocol based on SKB extensions to convey the
  19 information about the destination port to the MAC driver
  20
  21 Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
  22 ---
  23  Documentation/networking/dsa/dsa.rst | 13 +++++++-
  24  MAINTAINERS                          |  1 +
  25  include/linux/dsa/oob.h              | 16 +++++++++
  26  include/linux/skbuff.h               |  3 ++
  27  include/net/dsa.h                    |  2 ++
  28  net/core/skbuff.c                    | 10 ++++++
  29  net/dsa/Kconfig                      |  9 +++++
  30  net/dsa/Makefile                     |  1 +
  31  net/dsa/tag_oob.c                    | 49 ++++++++++++++++++++++++++++
  32  9 files changed, 103 insertions(+), 1 deletion(-)
  33  create mode 100644 include/linux/dsa/oob.h
  34  create mode 100644 net/dsa/tag_oob.c
  35
  36 --- a/Documentation/networking/dsa/dsa.rst
  37 +++ b/Documentation/networking/dsa/dsa.rst
  38 @@ -66,7 +66,8 @@ Switch tagging protocols
  39  ------------------------
  40
  41  DSA supports many vendor-specific tagging protocols, one software-defined
  42 -tagging protocol, and a tag-less mode as well (``DSA_TAG_PROTO_NONE``).
  43 +tagging protocol, a tag-less mode as well (``DSA_TAG_PROTO_NONE``) and an
  44 +out-of-band tagging protocol (``DSA_TAG_PROTO_OOB``).
  45
  46  The exact format of the tag protocol is vendor specific, but in general, they
  47  all contain something which:
  48 @@ -217,6 +218,16 @@ receive all frames regardless of the val
  49  setting the ``promisc_on_master`` property of the ``struct dsa_device_ops``.
  50  Note that this assumes a DSA-unaware master driver, which is the norm.
  51
  52 +Some SoCs have a tight integration between the conduit network interface and the
  53 +embedded switch, such that the DSA tag isn't transmitted in the packet data,
  54 +but through another media, using so-called out-of-band tagging. In that case,
  55 +the host MAC driver is in charge of transmitting the tag to the switch.
  56 +An example is the IPQ4019 SoC, that transmits the tag between the ipqess
  57 +ethernet controller and the qca8k switch using the DMA descriptor. In that
  58 +configuration, tag-chaining is permitted, but the OOB tag will always be the
  59 +top-most switch in the tree. The tagger (``DSA_TAG_PROTO_OOB``) uses skb
  60 +extensions to transmit the tag to and from the MAC driver.
  61 +
  62  Master network devices
  63  ----------------------
  64
  65 --- a/MAINTAINERS
  66 +++ b/MAINTAINERS
  67 @@ -17070,6 +17070,7 @@ L:      netdev@vger.kernel.org
  68  S:     Maintained
  69  F:     Documentation/devicetree/bindings/net/qcom,ipq4019-ess-edma.yaml
  70  F:     drivers/net/ethernet/qualcomm/ipqess/
  71 +F:     net/dsa/tag_oob.c
  72
  73  QUALCOMM ETHQOS ETHERNET DRIVER
  74  M:     Vinod Koul <vkoul@kernel.org>
  75 --- /dev/null
  76 +++ b/include/linux/dsa/oob.h
  77 @@ -0,0 +1,16 @@
  78 +/* SPDX-License-Identifier: GPL-2.0-only
  79 + * Copyright (C) 2022 Maxime Chevallier <maxime.chevallier@bootlin.com>
  80 + */
  81 +
  82 +#ifndef _NET_DSA_OOB_H
  83 +#define _NET_DSA_OOB_H
  84 +
  85 +#include <linux/skbuff.h>
  86 +
  87 +struct dsa_oob_tag_info {
  88 +       u16 port;
  89 +};
  90 +
  91 +int dsa_oob_tag_push(struct sk_buff *skb, struct dsa_oob_tag_info *ti);
  92 +int dsa_oob_tag_pop(struct sk_buff *skb, struct dsa_oob_tag_info *ti);
  93 +#endif
  94 --- a/include/linux/skbuff.h
  95 +++ b/include/linux/skbuff.h
  96 @@ -4588,6 +4588,9 @@ enum skb_ext_id {
  97  #if IS_ENABLED(CONFIG_MCTP_FLOWS)
  98         SKB_EXT_MCTP,
  99  #endif
 100 +#if IS_ENABLED(CONFIG_NET_DSA_TAG_OOB)
 101 +       SKB_EXT_DSA_OOB,
 102 +#endif
 103         SKB_EXT_NUM, /* must be last */
 104  };
 105
 106 --- a/include/net/dsa.h
 107 +++ b/include/net/dsa.h
 108 @@ -55,6 +55,7 @@ struct phylink_link_state;
 109  #define DSA_TAG_PROTO_RTL8_4T_VALUE            25
 110  #define DSA_TAG_PROTO_RZN1_A5PSW_VALUE         26
 111  #define DSA_TAG_PROTO_LAN937X_VALUE            27
 112 +#define DSA_TAG_PROTO_OOB_VALUE                        28
 113
 114  enum dsa_tag_protocol {
 115         DSA_TAG_PROTO_NONE              = DSA_TAG_PROTO_NONE_VALUE,
 116 @@ -85,6 +86,7 @@ enum dsa_tag_protocol {
 117         DSA_TAG_PROTO_RTL8_4T           = DSA_TAG_PROTO_RTL8_4T_VALUE,
 118         DSA_TAG_PROTO_RZN1_A5PSW        = DSA_TAG_PROTO_RZN1_A5PSW_VALUE,
 119         DSA_TAG_PROTO_LAN937X           = DSA_TAG_PROTO_LAN937X_VALUE,
 120 +       DSA_TAG_PROTO_OOB               = DSA_TAG_PROTO_OOB_VALUE,
 121  };
 122
 123  struct dsa_switch;
 124 --- a/net/core/skbuff.c
 125 +++ b/net/core/skbuff.c
 126 @@ -62,8 +62,12 @@
 127  #include <linux/mpls.h>
 128  #include <linux/kcov.h>
 129  #include <linux/if.h>
 130 +#ifdef CONFIG_NET_DSA_TAG_OOB
 131 +#include <linux/dsa/oob.h>
 132 +#endif
 133
 134  #include <net/protocol.h>
 135 +#include <net/dsa.h>
 136  #include <net/dst.h>
 137  #include <net/sock.h>
 138  #include <net/checksum.h>
 139 @@ -4516,6 +4520,9 @@ static const u8 skb_ext_type_len[] = {
 140  #if IS_ENABLED(CONFIG_MCTP_FLOWS)
 141         [SKB_EXT_MCTP] = SKB_EXT_CHUNKSIZEOF(struct mctp_flow),
 142  #endif
 143 +#if IS_ENABLED(CONFIG_NET_DSA_TAG_OOB)
 144 +       [SKB_EXT_DSA_OOB] = SKB_EXT_CHUNKSIZEOF(struct dsa_oob_tag_info),
 145 +#endif
 146  };
 147
 148  static __always_inline unsigned int skb_ext_total_length(void)
 149 @@ -4536,6 +4543,9 @@ static __always_inline unsigned int skb_
 150  #if IS_ENABLED(CONFIG_MCTP_FLOWS)
 151                 skb_ext_type_len[SKB_EXT_MCTP] +
 152  #endif
 153 +#if IS_ENABLED(CONFIG_NET_DSA_TAG_OOB)
 154 +               skb_ext_type_len[SKB_EXT_DSA_OOB] +
 155 +#endif
 156                 0;
 157  }
 158
 159 --- a/net/dsa/Kconfig
 160 +++ b/net/dsa/Kconfig
 161 @@ -113,6 +113,15 @@ config NET_DSA_TAG_OCELOT_8021Q
 162           this mode, less TCAM resources (VCAP IS1, IS2, ES0) are available for
 163           use with tc-flower.
 164
 165 +config NET_DSA_TAG_OOB
 166 +       select SKB_EXTENSIONS
 167 +       tristate "Tag driver for Out-of-band tagging drivers"
 168 +       help
 169 +         Say Y or M if you want to enable support for pairs of embedded
 170 +         switches and host MAC drivers which perform demultiplexing and
 171 +         packet steering to ports using out of band metadata processed
 172 +         by the DSA master, rather than tags present in the packets.
 173 +
 174  config NET_DSA_TAG_QCA
 175         tristate "Tag driver for Qualcomm Atheros QCA8K switches"
 176         help
 177 --- a/net/dsa/Makefile
 178 +++ b/net/dsa/Makefile
 179 @@ -22,6 +22,7 @@ obj-$(CONFIG_NET_DSA_TAG_LAN9303) += tag
 180  obj-$(CONFIG_NET_DSA_TAG_MTK) += tag_mtk.o
 181  obj-$(CONFIG_NET_DSA_TAG_OCELOT) += tag_ocelot.o
 182  obj-$(CONFIG_NET_DSA_TAG_OCELOT_8021Q) += tag_ocelot_8021q.o
 183 +obj-$(CONFIG_NET_DSA_TAG_OOB) += tag_oob.o
 184  obj-$(CONFIG_NET_DSA_TAG_QCA) += tag_qca.o
 185  obj-$(CONFIG_NET_DSA_TAG_RTL4_A) += tag_rtl4_a.o
 186  obj-$(CONFIG_NET_DSA_TAG_RTL8_4) += tag_rtl8_4.o
 187 --- /dev/null
 188 +++ b/net/dsa/tag_oob.c
 189 @@ -0,0 +1,49 @@
 190 +// SPDX-License-Identifier: GPL-2.0-only
 191 +
 192 +/* Copyright (c) 2022, Maxime Chevallier <maxime.chevallier@bootlin.com> */
 193 +
 194 +#include <linux/bitfield.h>
 195 +#include <linux/dsa/oob.h>
 196 +#include <linux/skbuff.h>
 197 +
 198 +#include "dsa_priv.h"
 199 +
 200 +static struct sk_buff *oob_tag_xmit(struct sk_buff *skb,
 201 +                                   struct net_device *dev)
 202 +{
 203 +       struct dsa_oob_tag_info *tag_info = skb_ext_add(skb, SKB_EXT_DSA_OOB);
 204 +       struct dsa_port *dp = dsa_slave_to_port(dev);
 205 +
 206 +       tag_info->port = dp->index;
 207 +
 208 +       return skb;
 209 +}
 210 +
 211 +static struct sk_buff *oob_tag_rcv(struct sk_buff *skb,
 212 +                                  struct net_device *dev)
 213 +{
 214 +       struct dsa_oob_tag_info *tag_info = skb_ext_find(skb, SKB_EXT_DSA_OOB);
 215 +
 216 +       if (!tag_info)
 217 +               return NULL;
 218 +
 219 +       skb->dev = dsa_master_find_slave(dev, 0, tag_info->port);
 220 +       if (!skb->dev)
 221 +               return NULL;
 222 +
 223 +       return skb;
 224 +}
 225 +
 226 +static const struct dsa_device_ops oob_tag_dsa_ops = {
 227 +       .name   = "oob",
 228 +       .proto  = DSA_TAG_PROTO_OOB,
 229 +       .xmit   = oob_tag_xmit,
 230 +       .rcv    = oob_tag_rcv,
 231 +};
 232 +
 233 +MODULE_LICENSE("GPL");
 234 +MODULE_DESCRIPTION("DSA tag driver for out-of-band tagging");
 235 +MODULE_AUTHOR("Maxime Chevallier <maxime.chevallier@bootlin.com>");
 236 +MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_OOB);
 237 +
 238 +module_dsa_tag_driver(oob_tag_dsa_ops);