diff options
Diffstat (limited to 'drivers/net/realtek-dsa/tag_rtl4_a.c')
| -rw-r--r-- | drivers/net/realtek-dsa/tag_rtl4_a.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/drivers/net/realtek-dsa/tag_rtl4_a.c b/drivers/net/realtek-dsa/tag_rtl4_a.c new file mode 100644 index 0000000000..30c6a712d9 --- /dev/null +++ b/drivers/net/realtek-dsa/tag_rtl4_a.c @@ -0,0 +1,104 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Handler for Realtek 4 byte DSA switch tags + * Currently only supports protocol "A" found in RTL8366RB + * Copyright (c) 2020 Linus Walleij <linus.walleij@linaro.org> + * + * This "proprietary tag" header looks like so: + * + * ------------------------------------------------- + * | MAC DA | MAC SA | 0x8899 | 2 bytes tag | Type | + * ------------------------------------------------- + * + * The 2 bytes tag form a 16 bit big endian word. The exact + * meaning has been guessed from packet dumps from ingress + * frames. + */ + +#include <net.h> +#include <linux/printk.h> + +#include "realtek.h" +#include "dsa_priv.h" + +#define RTL4_A_HDR_LEN 4 +#define RTL4_A_ETHERTYPE 0x8899 +#define RTL4_A_PROTOCOL_SHIFT 12 +/* + * 0x1 = Realtek Remote Control protocol (RRCP) + * 0x2/0x3 seems to be used for loopback testing + * 0x9 = RTL8306 DSA protocol + * 0xa = RTL8366RB DSA protocol + */ +#define RTL4_A_PROTOCOL_RTL8366RB 0xa + +static int rtl4a_tag_xmit(struct dsa_port *dp, int port, void *packet, int length) +{ + struct device *dev = dp->ds->dev; + __be16 *p; + u8 *tag; + u16 out; + + /* DSA core already pads out to at least 60 bytes */ + + dev_dbg(dev, "add realtek tag to package to port %d\n", port); + + dsa_alloc_etype_header(packet, RTL4_A_HDR_LEN); + tag = dsa_etype_header_pos(packet); + + /* Set Ethertype */ + p = (__be16 *)tag; + *p = htons(RTL4_A_ETHERTYPE); + + out = (RTL4_A_PROTOCOL_RTL8366RB << RTL4_A_PROTOCOL_SHIFT); + /* The lower bits indicate the port number */ + out |= BIT(port); + + p = (__be16 *)(tag + 2); + *p = htons(out); + + return 0; +} + +static int rtl4a_tag_rcv(struct dsa_switch *ds, int *port, void *packet, int length) +{ + struct device *dev = ds->dev; + u16 protport; + __be16 *p; + u16 etype; + u8 *tag; + u8 prot; + + tag = packet + 2 * ETH_ALEN; + p = (__be16 *)tag; + etype = ntohs(*p); + if (etype != RTL4_A_ETHERTYPE) { + /* Not custom, just pass through */ + dev_dbg(dev, "non-realtek ethertype 0x%04x\n", etype); + return -EINVAL; + } + p = (__be16 *)(tag + 2); + protport = ntohs(*p); + /* The 4 upper bits are the protocol */ + prot = (protport >> RTL4_A_PROTOCOL_SHIFT) & 0x0f; + if (prot != RTL4_A_PROTOCOL_RTL8366RB) { + dev_err(dev, "unknown realtek protocol 0x%01x\n", prot); + return -EPROTO; + } + *port = protport & 0xff; + + dsa_strip_etype_header(packet, RTL4_A_HDR_LEN); + + return 0; +} + +const struct dsa_device_ops rtl4a_netdev_ops = { + .name = "rtl4a", + .proto = DSA_TAG_PROTO_RTL4_A, + .xmit = rtl4a_tag_xmit, + .rcv = rtl4a_tag_rcv, + .needed_headroom = RTL4_A_HDR_LEN, +}; + +MODULE_LICENSE("GPL"); +MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_RTL4_A); |