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(80.71.142.18.ipv4.parknet.dk. [80.71.142.18]) by smtp.gmail.com with ESMTPSA id jt24sm4735792ejb.59.2021.10.15.10.10.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 Oct 2021 10:10:59 -0700 (PDT) From: =?utf-8?q?Alvin_=C5=A0ipraga?= To: Linus Walleij , Andrew Lunn , Vivien Didelot , Florian Fainelli , Vladimir Oltean , "David S. Miller" , Jakub Kicinski , Rob Herring , Heiner Kallweit , Russell King Cc: =?utf-8?q?Alvin_=C5=A0ipraga?= , netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 net-next 5/7] net: dsa: tag_rtl8_4: add realtek 8 byte protocol 4 tag Date: Fri, 15 Oct 2021 19:10:26 +0200 Message-Id: <20211015171030.2713493-6-alvin@pqrs.dk> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20211015171030.2713493-1-alvin@pqrs.dk> References: <20211015171030.2713493-1-alvin@pqrs.dk> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: Alvin Šipraga This commit implements a basic version of the 8 byte tag protocol used in the Realtek RTL8365MB-VC unmanaged switch, which carries with it a protocol version of 0x04. The implementation itself only handles the parsing of the EtherType value and Realtek protocol version, together with the source or destination port fields. The rest is left unimplemented for now. The tag format is described in a confidential document provided to my company by Realtek Semiconductor Corp. Permission has been granted by the vendor to publish this driver based on that material, together with an extract from the document describing the tag format and its fields. It is hoped that this will help future implementors who do not have access to the material but who wish to extend the functionality of drivers for chips which use this protocol. In addition, two possible values of the REASON field are specified, based on experiments on my end. Realtek does not specify what value this field can take. Signed-off-by: Alvin Šipraga Reviewed-by: Vladimir Oltean Reviewed-by: Linus Walleij Reviewed-by: Florian Fainelli --- v2 -> v3: - add bitfield.h include - collect Reviewed-by from Florian v1 -> v2: - collect Reviewed-by from Vladimir and Linus - don't set default fwd_offload_mark if packet is trapped to CPU - use #defines and FIELD_* macros to make Linus happy RFC -> v1: - minor changes to the big comment at the top, including some empirical information about the REASON code - use dev_*_ratelimited() instead of netdev_*() for logging - use warning instead of debug messages - use ETH_P_REALTEK from if_ether.h - set LEARN_DIS on xmit - remove superfluous variables/expressions and use __b16 for tag variable - use new helper functions to insert/remove CPU tag - set offload_fwd_mark properly using helper function include/net/dsa.h | 2 + net/dsa/Kconfig | 6 ++ net/dsa/Makefile | 1 + net/dsa/tag_rtl8_4.c | 185 +++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 194 insertions(+) create mode 100644 net/dsa/tag_rtl8_4.c diff --git a/include/net/dsa.h b/include/net/dsa.h index 8fefd58ced8f..05ebdd8d5321 100644 --- a/include/net/dsa.h +++ b/include/net/dsa.h @@ -51,6 +51,7 @@ struct phylink_link_state; #define DSA_TAG_PROTO_SEVILLE_VALUE 21 #define DSA_TAG_PROTO_BRCM_LEGACY_VALUE 22 #define DSA_TAG_PROTO_SJA1110_VALUE 23 +#define DSA_TAG_PROTO_RTL8_4_VALUE 24 enum dsa_tag_protocol { DSA_TAG_PROTO_NONE = DSA_TAG_PROTO_NONE_VALUE, @@ -77,6 +78,7 @@ enum dsa_tag_protocol { DSA_TAG_PROTO_OCELOT_8021Q = DSA_TAG_PROTO_OCELOT_8021Q_VALUE, DSA_TAG_PROTO_SEVILLE = DSA_TAG_PROTO_SEVILLE_VALUE, DSA_TAG_PROTO_SJA1110 = DSA_TAG_PROTO_SJA1110_VALUE, + DSA_TAG_PROTO_RTL8_4 = DSA_TAG_PROTO_RTL8_4_VALUE, }; struct dsa_switch; diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig index 3a09784dae63..8cb87b5067ee 100644 --- a/net/dsa/Kconfig +++ b/net/dsa/Kconfig @@ -126,6 +126,12 @@ config NET_DSA_TAG_RTL4_A Realtek switches with 4 byte protocol A tags, sich as found in the Realtek RTL8366RB. +config NET_DSA_TAG_RTL8_4 + tristate "Tag driver for Realtek 8 byte protocol 4 tags" + help + Say Y or M if you want to enable support for tagging frames for Realtek + switches with 8 byte protocol 4 tags, such as the Realtek RTL8365MB-VC. + config NET_DSA_TAG_LAN9303 tristate "Tag driver for SMSC/Microchip LAN9303 family of switches" help diff --git a/net/dsa/Makefile b/net/dsa/Makefile index f78d537044db..9f75820e7c98 100644 --- a/net/dsa/Makefile +++ b/net/dsa/Makefile @@ -16,6 +16,7 @@ obj-$(CONFIG_NET_DSA_TAG_OCELOT) += tag_ocelot.o obj-$(CONFIG_NET_DSA_TAG_OCELOT_8021Q) += tag_ocelot_8021q.o obj-$(CONFIG_NET_DSA_TAG_QCA) += tag_qca.o obj-$(CONFIG_NET_DSA_TAG_RTL4_A) += tag_rtl4_a.o +obj-$(CONFIG_NET_DSA_TAG_RTL8_4) += tag_rtl8_4.o obj-$(CONFIG_NET_DSA_TAG_SJA1105) += tag_sja1105.o obj-$(CONFIG_NET_DSA_TAG_TRAILER) += tag_trailer.o obj-$(CONFIG_NET_DSA_TAG_XRS700X) += tag_xrs700x.o diff --git a/net/dsa/tag_rtl8_4.c b/net/dsa/tag_rtl8_4.c new file mode 100644 index 000000000000..831adda84610 --- /dev/null +++ b/net/dsa/tag_rtl8_4.c @@ -0,0 +1,185 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Handler for Realtek 8 byte switch tags + * + * Copyright (C) 2021 Alvin Šipraga + * + * NOTE: Currently only supports protocol "4" found in the RTL8365MB, hence + * named tag_rtl8_4. + * + * This tag header has the following format: + * + * ------------------------------------------- + * | MAC DA | MAC SA | 8 byte tag | Type | ... + * ------------------------------------------- + * _______________/ \______________________________________ + * / \ + * 0 7|8 15 + * |-----------------------------------+-----------------------------------|--- + * | (16-bit) | ^ + * | Realtek EtherType [0x8899] | | + * |-----------------------------------+-----------------------------------| 8 + * | (8-bit) | (8-bit) | + * | Protocol [0x04] | REASON | b + * |-----------------------------------+-----------------------------------| y + * | (1) | (1) | (2) | (1) | (3) | (1) | (1) | (1) | (5) | t + * | FID_EN | X | FID | PRI_EN | PRI | KEEP | X | LEARN_DIS | X | e + * |-----------------------------------+-----------------------------------| s + * | (1) | (15-bit) | | + * | ALLOW | TX/RX | v + * |-----------------------------------+-----------------------------------|--- + * + * With the following field descriptions: + * + * field | description + * ------------+------------- + * Realtek | 0x8899: indicates that this is a proprietary Realtek tag; + * EtherType | note that Realtek uses the same EtherType for + * | other incompatible tag formats (e.g. tag_rtl4_a.c) + * Protocol | 0x04: indicates that this tag conforms to this format + * X | reserved + * ------------+------------- + * REASON | reason for forwarding packet to CPU + * | 0: packet was forwarded or flooded to CPU + * | 80: packet was trapped to CPU + * FID_EN | 1: packet has an FID + * | 0: no FID + * FID | FID of packet (if FID_EN=1) + * PRI_EN | 1: force priority of packet + * | 0: don't force priority + * PRI | priority of packet (if PRI_EN=1) + * KEEP | preserve packet VLAN tag format + * LEARN_DIS | don't learn the source MAC address of the packet + * ALLOW | 1: treat TX/RX field as an allowance port mask, meaning the + * | packet may only be forwarded to ports specified in the + * | mask + * | 0: no allowance port mask, TX/RX field is the forwarding + * | port mask + * TX/RX | TX (switch->CPU): port number the packet was received on + * | RX (CPU->switch): forwarding port mask (if ALLOW=0) + * | allowance port mask (if ALLOW=1) + */ + +#include +#include +#include + +#include "dsa_priv.h" + +/* Protocols supported: + * + * 0x04 = RTL8365MB DSA protocol + */ + +#define RTL8_4_TAG_LEN 8 + +#define RTL8_4_PROTOCOL GENMASK(15, 8) +#define RTL8_4_PROTOCOL_RTL8365MB 0x04 +#define RTL8_4_REASON GENMASK(7, 0) +#define RTL8_4_REASON_FORWARD 0 +#define RTL8_4_REASON_TRAP 80 + +#define RTL8_4_LEARN_DIS BIT(5) + +#define RTL8_4_TX GENMASK(3, 0) +#define RTL8_4_RX GENMASK(10, 0) + +static struct sk_buff *rtl8_4_tag_xmit(struct sk_buff *skb, + struct net_device *dev) +{ + struct dsa_port *dp = dsa_slave_to_port(dev); + __be16 *tag; + + /* Pad out so the (stripped) packet is at least 64 bytes long + * (including FCS), otherwise the switch will drop the packet. + * Then we need an additional 8 bytes for the Realtek tag. + */ + if (unlikely(__skb_put_padto(skb, ETH_ZLEN + RTL8_4_TAG_LEN, false))) + return NULL; + + skb_push(skb, RTL8_4_TAG_LEN); + + dsa_alloc_etype_header(skb, RTL8_4_TAG_LEN); + tag = dsa_etype_header_pos_tx(skb); + + /* Set Realtek EtherType */ + tag[0] = htons(ETH_P_REALTEK); + + /* Set Protocol; zero REASON */ + tag[1] = htons(FIELD_PREP(RTL8_4_PROTOCOL, RTL8_4_PROTOCOL_RTL8365MB)); + + /* Zero FID_EN, FID, PRI_EN, PRI, KEEP; set LEARN_DIS */ + tag[2] = htons(FIELD_PREP(RTL8_4_LEARN_DIS, 1)); + + /* Zero ALLOW; set RX (CPU->switch) forwarding port mask */ + tag[3] = htons(FIELD_PREP(RTL8_4_RX, BIT(dp->index))); + + return skb; +} + +static struct sk_buff *rtl8_4_tag_rcv(struct sk_buff *skb, + struct net_device *dev) +{ + __be16 *tag; + u16 etype; + u8 reason; + u8 proto; + u8 port; + + if (unlikely(!pskb_may_pull(skb, RTL8_4_TAG_LEN))) + return NULL; + + tag = dsa_etype_header_pos_rx(skb); + + /* Parse Realtek EtherType */ + etype = ntohs(tag[0]); + if (unlikely(etype != ETH_P_REALTEK)) { + dev_warn_ratelimited(&dev->dev, + "non-realtek ethertype 0x%04x\n", etype); + return NULL; + } + + /* Parse Protocol */ + proto = FIELD_GET(RTL8_4_PROTOCOL, ntohs(tag[1])); + if (unlikely(proto != RTL8_4_PROTOCOL_RTL8365MB)) { + dev_warn_ratelimited(&dev->dev, + "unknown realtek protocol 0x%02x\n", + proto); + return NULL; + } + + /* Parse REASON */ + reason = FIELD_GET(RTL8_4_REASON, ntohs(tag[1])); + + /* Parse TX (switch->CPU) */ + port = FIELD_GET(RTL8_4_TX, ntohs(tag[3])); + skb->dev = dsa_master_find_slave(dev, 0, port); + if (!skb->dev) { + dev_warn_ratelimited(&dev->dev, + "could not find slave for port %d\n", + port); + return NULL; + } + + /* Remove tag and recalculate checksum */ + skb_pull_rcsum(skb, RTL8_4_TAG_LEN); + + dsa_strip_etype_header(skb, RTL8_4_TAG_LEN); + + if (reason != RTL8_4_REASON_TRAP) + dsa_default_offload_fwd_mark(skb); + + return skb; +} + +static const struct dsa_device_ops rtl8_4_netdev_ops = { + .name = "rtl8_4", + .proto = DSA_TAG_PROTO_RTL8_4, + .xmit = rtl8_4_tag_xmit, + .rcv = rtl8_4_tag_rcv, + .needed_headroom = RTL8_4_TAG_LEN, +}; +module_dsa_tag_driver(rtl8_4_netdev_ops); + +MODULE_LICENSE("GPL"); +MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_RTL8_4);