From: Álvaro Fernández Rojas Date: Sat, 14 Jun 2025 07:59:48 +0000 (+0200) Subject: net: dsa: tag_brcm: add support for legacy FCS tags X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ef07df397a621707903ef0d294a7df11f80cf206;p=thirdparty%2Flinux.git net: dsa: tag_brcm: add support for legacy FCS tags Add support for legacy Broadcom FCS tags, which are similar to DSA_TAG_PROTO_BRCM_LEGACY. BCM5325 and BCM5365 switches require including the original FCS value and length, as opposed to BCM63xx switches. Adding the original FCS value and length to DSA_TAG_PROTO_BRCM_LEGACY would impact performance of BCM63xx switches, so it's better to create a new tag. Signed-off-by: Álvaro Fernández Rojas Reviewed-by: Florian Fainelli Link: https://patch.msgid.link/20250614080000.1884236-3-noltari@gmail.com Signed-off-by: Jakub Kicinski --- diff --git a/include/net/dsa.h b/include/net/dsa.h index 55e2d97f247eb..d73ea08800660 100644 --- a/include/net/dsa.h +++ b/include/net/dsa.h @@ -54,11 +54,13 @@ struct tc_action; #define DSA_TAG_PROTO_RZN1_A5PSW_VALUE 26 #define DSA_TAG_PROTO_LAN937X_VALUE 27 #define DSA_TAG_PROTO_VSC73XX_8021Q_VALUE 28 +#define DSA_TAG_PROTO_BRCM_LEGACY_FCS_VALUE 29 enum dsa_tag_protocol { DSA_TAG_PROTO_NONE = DSA_TAG_PROTO_NONE_VALUE, DSA_TAG_PROTO_BRCM = DSA_TAG_PROTO_BRCM_VALUE, DSA_TAG_PROTO_BRCM_LEGACY = DSA_TAG_PROTO_BRCM_LEGACY_VALUE, + DSA_TAG_PROTO_BRCM_LEGACY_FCS = DSA_TAG_PROTO_BRCM_LEGACY_FCS_VALUE, DSA_TAG_PROTO_BRCM_PREPEND = DSA_TAG_PROTO_BRCM_PREPEND_VALUE, DSA_TAG_PROTO_DSA = DSA_TAG_PROTO_DSA_VALUE, DSA_TAG_PROTO_EDSA = DSA_TAG_PROTO_EDSA_VALUE, diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig index 2dfe9063613fe..869cbe57162f9 100644 --- a/net/dsa/Kconfig +++ b/net/dsa/Kconfig @@ -42,12 +42,24 @@ config NET_DSA_TAG_BRCM Broadcom switches which place the tag after the MAC source address. config NET_DSA_TAG_BRCM_LEGACY - tristate "Tag driver for Broadcom legacy switches using in-frame headers" + tristate "Tag driver for BCM63xx legacy switches using in-frame headers" select NET_DSA_TAG_BRCM_COMMON help Say Y if you want to enable support for tagging frames for the - Broadcom legacy switches which place the tag after the MAC source + BCM63xx legacy switches which place the tag after the MAC source address. + This tag is used in BCM63xx legacy switches which work without the + original FCS and length before the tag insertion. + +config NET_DSA_TAG_BRCM_LEGACY_FCS + tristate "Tag driver for BCM53xx legacy switches using in-frame headers" + select NET_DSA_TAG_BRCM_COMMON + help + Say Y if you want to enable support for tagging frames for the + BCM53xx legacy switches which place the tag after the MAC source + address. + This tag is used in BCM53xx legacy switches which expect original + FCS and length before the tag insertion to be present. config NET_DSA_TAG_BRCM_PREPEND tristate "Tag driver for Broadcom switches using prepended headers" diff --git a/net/dsa/tag_brcm.c b/net/dsa/tag_brcm.c index 9f4b0bcd95cde..26bb657ceac36 100644 --- a/net/dsa/tag_brcm.c +++ b/net/dsa/tag_brcm.c @@ -15,6 +15,7 @@ #define BRCM_NAME "brcm" #define BRCM_LEGACY_NAME "brcm-legacy" +#define BRCM_LEGACY_FCS_NAME "brcm-legacy-fcs" #define BRCM_PREPEND_NAME "brcm-prepend" /* Legacy Broadcom tag (6 bytes) */ @@ -32,6 +33,10 @@ #define BRCM_LEG_MULTICAST (1 << 5) #define BRCM_LEG_EGRESS (2 << 5) #define BRCM_LEG_INGRESS (3 << 5) +#define BRCM_LEG_LEN_HI(x) (((x) >> 8) & 0x7) + +/* 4th byte in the tag */ +#define BRCM_LEG_LEN_LO(x) ((x) & 0xff) /* 6th byte in the tag */ #define BRCM_LEG_PORT_ID (0xf) @@ -212,7 +217,8 @@ DSA_TAG_DRIVER(brcm_netdev_ops); MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM, BRCM_NAME); #endif -#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY) +#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY) || \ + IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY_FCS) static struct sk_buff *brcm_leg_tag_rcv(struct sk_buff *skb, struct net_device *dev) { @@ -244,7 +250,9 @@ static struct sk_buff *brcm_leg_tag_rcv(struct sk_buff *skb, return skb; } +#endif /* CONFIG_NET_DSA_TAG_BRCM_LEGACY || CONFIG_NET_DSA_TAG_BRCM_LEGACY_FCS */ +#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY) static struct sk_buff *brcm_leg_tag_xmit(struct sk_buff *skb, struct net_device *dev) { @@ -294,6 +302,66 @@ DSA_TAG_DRIVER(brcm_legacy_netdev_ops); MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_LEGACY, BRCM_LEGACY_NAME); #endif /* CONFIG_NET_DSA_TAG_BRCM_LEGACY */ +#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY_FCS) +static struct sk_buff *brcm_leg_fcs_tag_xmit(struct sk_buff *skb, + struct net_device *dev) +{ + struct dsa_port *dp = dsa_user_to_port(dev); + unsigned int fcs_len; + __le32 fcs_val; + u8 *brcm_tag; + + /* The Ethernet switch we are interfaced with needs packets to be at + * least 64 bytes (including FCS) otherwise they will be discarded when + * they enter the switch port logic. When Broadcom tags are enabled, we + * need to make sure that packets are at least 70 bytes (including FCS + * and tag) because the length verification is done after the Broadcom + * tag is stripped off the ingress packet. + * + * Let dsa_user_xmit() free the SKB. + */ + if (__skb_put_padto(skb, ETH_ZLEN + BRCM_LEG_TAG_LEN, false)) + return NULL; + + fcs_len = skb->len; + fcs_val = cpu_to_le32(crc32_le(~0, skb->data, fcs_len) ^ ~0); + + skb_push(skb, BRCM_LEG_TAG_LEN); + + dsa_alloc_etype_header(skb, BRCM_LEG_TAG_LEN); + + brcm_tag = skb->data + 2 * ETH_ALEN; + + /* Broadcom tag type */ + brcm_tag[0] = BRCM_LEG_TYPE_HI; + brcm_tag[1] = BRCM_LEG_TYPE_LO; + + /* Broadcom tag value */ + brcm_tag[2] = BRCM_LEG_EGRESS | BRCM_LEG_LEN_HI(fcs_len); + brcm_tag[3] = BRCM_LEG_LEN_LO(fcs_len); + brcm_tag[4] = 0; + brcm_tag[5] = dp->index & BRCM_LEG_PORT_ID; + + /* Original FCS value */ + if (__skb_pad(skb, ETH_FCS_LEN, false)) + return NULL; + skb_put_data(skb, &fcs_val, ETH_FCS_LEN); + + return skb; +} + +static const struct dsa_device_ops brcm_legacy_fcs_netdev_ops = { + .name = BRCM_LEGACY_FCS_NAME, + .proto = DSA_TAG_PROTO_BRCM_LEGACY_FCS, + .xmit = brcm_leg_fcs_tag_xmit, + .rcv = brcm_leg_tag_rcv, + .needed_headroom = BRCM_LEG_TAG_LEN, +}; + +DSA_TAG_DRIVER(brcm_legacy_fcs_netdev_ops); +MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM_LEGACY_FCS, BRCM_LEGACY_FCS_NAME); +#endif /* CONFIG_NET_DSA_TAG_BRCM_LEGACY_FCS */ + #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND) static struct sk_buff *brcm_tag_xmit_prepend(struct sk_buff *skb, struct net_device *dev) @@ -328,6 +396,9 @@ static struct dsa_tag_driver *dsa_tag_driver_array[] = { #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY) &DSA_TAG_DRIVER_NAME(brcm_legacy_netdev_ops), #endif +#if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_LEGACY_FCS) + &DSA_TAG_DRIVER_NAME(brcm_legacy_fcs_netdev_ops), +#endif #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM_PREPEND) &DSA_TAG_DRIVER_NAME(brcm_prepend_netdev_ops), #endif