[linux-block.git] / net / dsa / tag_lan9303.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2017 Pengutronix, Juergen Borleis <jbe@pengutronix.de>
 */
#include <linux/dsa/lan9303.h>
#include <linux/etherdevice.h>
#include <linux/list.h>
#include <linux/slab.h>

#include "dsa_priv.h"

/* To define the outgoing port and to discover the incoming port a regular
 * VLAN tag is used by the LAN9303. But its VID meaning is 'special':
 *
 *       Dest MAC       Src MAC        TAG    Type
 * ...| 1 2 3 4 5 6 | 1 2 3 4 5 6 | 1 2 3 4 | 1 2 |...
 *                                |<------->|
 * TAG:
 *    |<------------->|
 *    |  1  2 | 3  4  |
 *      TPID    VID
 *     0x8100
 *
 * VID bit 3 indicates a request for an ALR lookup.
 *
 * If VID bit 3 is zero, then bits 0 and 1 specify the destination port
 * (0, 1, 2) or broadcast (3) or the source port (1, 2).
 *
 * VID bit 4 is used to specify if the STP port state should be overridden.
 * Required when no forwarding between the external ports should happen.
 */

#define LAN9303_TAG_LEN 4
# define LAN9303_TAG_TX_USE_ALR BIT(3)
# define LAN9303_TAG_TX_STP_OVERRIDE BIT(4)
# define LAN9303_TAG_RX_IGMP BIT(3)
# define LAN9303_TAG_RX_STP BIT(4)
# define LAN9303_TAG_RX_TRAPPED_TO_CPU (LAN9303_TAG_RX_IGMP | \
					LAN9303_TAG_RX_STP)

/* Decide whether to transmit using ALR lookup, or transmit directly to
 * port using tag. ALR learning is performed only when using ALR lookup.
 * If the two external ports are bridged and the frame is unicast,
 * then use ALR lookup to allow ALR learning on CPU port.
 * Otherwise transmit directly to port with STP state override.
 * See also: lan9303_separate_ports() and lan9303.pdf 6.4.10.1
 */
static int lan9303_xmit_use_arl(struct dsa_port *dp, u8 *dest_addr)
{
	struct lan9303 *chip = dp->ds->priv;

	return chip->is_bridged && !is_multicast_ether_addr(dest_addr);
}

static struct sk_buff *lan9303_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct dsa_port *dp = dsa_slave_to_port(dev);
	__be16 *lan9303_tag;
	u16 tag;

	/* provide 'LAN9303_TAG_LEN' bytes additional space */
	skb_push(skb, LAN9303_TAG_LEN);

	/* make room between MACs and Ether-Type */
	memmove(skb->data, skb->data + LAN9303_TAG_LEN, 2 * ETH_ALEN);

	lan9303_tag = (__be16 *)(skb->data + 2 * ETH_ALEN);
	tag = lan9303_xmit_use_arl(dp, skb->data) ?
		LAN9303_TAG_TX_USE_ALR :
		dp->index | LAN9303_TAG_TX_STP_OVERRIDE;
	lan9303_tag[0] = htons(ETH_P_8021Q);
	lan9303_tag[1] = htons(tag);

	return skb;
}

static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev,
				   struct packet_type *pt)
{
	__be16 *lan9303_tag;
	u16 lan9303_tag1;
	unsigned int source_port;

	if (unlikely(!pskb_may_pull(skb, LAN9303_TAG_LEN))) {
		dev_warn_ratelimited(&dev->dev,
				     "Dropping packet, cannot pull\n");
		return NULL;
	}

	/* '->data' points into the middle of our special VLAN tag information:
	 *
	 * ~ MAC src   | 0x81 | 0x00 | 0xyy | 0xzz | ether type
	 *                           ^
	 *                        ->data
	 */
	lan9303_tag = (__be16 *)(skb->data - 2);

	if (lan9303_tag[0] != htons(ETH_P_8021Q)) {
		dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid VLAN marker\n");
		return NULL;
	}

	lan9303_tag1 = ntohs(lan9303_tag[1]);
	source_port = lan9303_tag1 & 0x3;

	skb->dev = dsa_master_find_slave(dev, 0, source_port);
	if (!skb->dev) {
		dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid source port\n");
		return NULL;
	}

	/* remove the special VLAN tag between the MAC addresses
	 * and the current ethertype field.
	 */
	skb_pull_rcsum(skb, 2 + 2);
	memmove(skb->data - ETH_HLEN, skb->data - (ETH_HLEN + LAN9303_TAG_LEN),
		2 * ETH_ALEN);
	skb->offload_fwd_mark = !(lan9303_tag1 & LAN9303_TAG_RX_TRAPPED_TO_CPU);

	return skb;
}

static const struct dsa_device_ops lan9303_netdev_ops = {
	.name = "lan9303",
	.proto	= DSA_TAG_PROTO_LAN9303,
	.xmit = lan9303_xmit,
	.rcv = lan9303_rcv,
	.overhead = LAN9303_TAG_LEN,
};

MODULE_LICENSE("GPL");
MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_LAN9303);

module_dsa_tag_driver(lan9303_netdev_ops);
Commit	Line	Data
dfedd3b6	1	// SPDX-License-Identifier: GPL-2.0
e8fe177a JB	2	/*
e8fe177a JB	3	* Copyright (C) 2017 Pengutronix, Juergen Borleis <jbe@pengutronix.de>
e8fe177a	4	*/
535f010d	5	#include <linux/dsa/lan9303.h>
e8fe177a JB	6	#include <linux/etherdevice.h>
	7	#include <linux/list.h>
	8	#include <linux/slab.h>
ea5dd34b	9
e8fe177a JB	10	#include "dsa_priv.h"
	11
	12	/* To define the outgoing port and to discover the incoming port a regular
	13	* VLAN tag is used by the LAN9303. But its VID meaning is 'special':
	14	*
	15	* Dest MAC Src MAC TAG Type
	16	* ...\| 1 2 3 4 5 6 \| 1 2 3 4 5 6 \| 1 2 3 4 \| 1 2 \|...
	17	* \|<------->\|
	18	* TAG:
	19	* \|<------------->\|
	20	* \| 1 2 \| 3 4 \|
	21	* TPID VID
	22	* 0x8100
	23	*
	24	* VID bit 3 indicates a request for an ALR lookup.
	25	*
	26	* If VID bit 3 is zero, then bits 0 and 1 specify the destination port
	27	* (0, 1, 2) or broadcast (3) or the source port (1, 2).
	28	*
	29	* VID bit 4 is used to specify if the STP port state should be overridden.
	30	* Required when no forwarding between the external ports should happen.
	31	*/
	32
	33	#define LAN9303_TAG_LEN 4
535f010d EH	34	# define LAN9303_TAG_TX_USE_ALR BIT(3)
535f010d EH	35	# define LAN9303_TAG_TX_STP_OVERRIDE BIT(4)
1a48fbd9 EH	36	# define LAN9303_TAG_RX_IGMP BIT(3)
	37	# define LAN9303_TAG_RX_STP BIT(4)
	38	# define LAN9303_TAG_RX_TRAPPED_TO_CPU (LAN9303_TAG_RX_IGMP \| \
	39	LAN9303_TAG_RX_STP)
535f010d EH	40
	41	/* Decide whether to transmit using ALR lookup, or transmit directly to
	42	* port using tag. ALR learning is performed only when using ALR lookup.
909fb9ae	43	* If the two external ports are bridged and the frame is unicast,
535f010d EH	44	* then use ALR lookup to allow ALR learning on CPU port.
	45	* Otherwise transmit directly to port with STP state override.
	46	* See also: lan9303_separate_ports() and lan9303.pdf 6.4.10.1
	47	*/
	48	static int lan9303_xmit_use_arl(struct dsa_port dp, u8 dest_addr)
	49	{
	50	struct lan9303 *chip = dp->ds->priv;
	51
909fb9ae	52	return chip->is_bridged && !is_multicast_ether_addr(dest_addr);
535f010d	53	}
e8fe177a JB	54
	55	static struct sk_buff lan9303_xmit(struct sk_buff skb, struct net_device *dev)
	56	{
d945097b	57	struct dsa_port *dp = dsa_slave_to_port(dev);
802734ad AL	58	__be16 *lan9303_tag;
802734ad AL	59	u16 tag;
e8fe177a	60
e8fe177a JB	61	/* provide 'LAN9303_TAG_LEN' bytes additional space */
	62	skb_push(skb, LAN9303_TAG_LEN);
	63
	64	/* make room between MACs and Ether-Type */
	65	memmove(skb->data, skb->data + LAN9303_TAG_LEN, 2 * ETH_ALEN);
	66
802734ad AL	67	lan9303_tag = (__be16 )(skb->data + 2 ETH_ALEN);
	68	tag = lan9303_xmit_use_arl(dp, skb->data) ?
	69	LAN9303_TAG_TX_USE_ALR :
	70	dp->index \| LAN9303_TAG_TX_STP_OVERRIDE;
e8fe177a	71	lan9303_tag[0] = htons(ETH_P_8021Q);
802734ad	72	lan9303_tag[1] = htons(tag);
e8fe177a JB	73
e8fe177a JB	74	return skb;
e8fe177a JB	75	}
	76
	77	static struct sk_buff lan9303_rcv(struct sk_buff skb, struct net_device *dev,
92f25caf	78	struct packet_type *pt)
e8fe177a	79	{
802734ad	80	__be16 *lan9303_tag;
1a48fbd9	81	u16 lan9303_tag1;
e8fe177a JB	82	unsigned int source_port;
e8fe177a JB	83
e8fe177a JB	84	if (unlikely(!pskb_may_pull(skb, LAN9303_TAG_LEN))) {
	85	dev_warn_ratelimited(&dev->dev,
	86	"Dropping packet, cannot pull\n");
	87	return NULL;
	88	}
	89
	90	/* '->data' points into the middle of our special VLAN tag information:
	91	*
	92	* ~ MAC src \| 0x81 \| 0x00 \| 0xyy \| 0xzz \| ether type
	93	* ^
	94	* ->data
	95	*/
802734ad	96	lan9303_tag = (__be16 *)(skb->data - 2);
e8fe177a JB	97
	98	if (lan9303_tag[0] != htons(ETH_P_8021Q)) {
	99	dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid VLAN marker\n");
	100	return NULL;
	101	}
	102
1a48fbd9 EH	103	lan9303_tag1 = ntohs(lan9303_tag[1]);
1a48fbd9 EH	104	source_port = lan9303_tag1 & 0x3;
e8fe177a	105
2231c43b	106	skb->dev = dsa_master_find_slave(dev, 0, source_port);
3775b1b7	107	if (!skb->dev) {
e8fe177a JB	108	dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid source port\n");
	109	return NULL;
	110	}
	111
e8fe177a JB	112	/* remove the special VLAN tag between the MAC addresses
	113	* and the current ethertype field.
	114	*/
	115	skb_pull_rcsum(skb, 2 + 2);
	116	memmove(skb->data - ETH_HLEN, skb->data - (ETH_HLEN + LAN9303_TAG_LEN),
	117	2 * ETH_ALEN);
1a48fbd9	118	skb->offload_fwd_mark = !(lan9303_tag1 & LAN9303_TAG_RX_TRAPPED_TO_CPU);
4672cd36	119
e8fe177a JB	120	return skb;
	121	}
	122
f81a43e8	123	static const struct dsa_device_ops lan9303_netdev_ops = {
875138f8	124	.name = "lan9303",
056eed2f	125	.proto = DSA_TAG_PROTO_LAN9303,
e8fe177a JB	126	.xmit = lan9303_xmit,
e8fe177a JB	127	.rcv = lan9303_rcv,
a5dd3087	128	.overhead = LAN9303_TAG_LEN,
e8fe177a	129	};
0b42f033	130
f18bba50	131	MODULE_LICENSE("GPL");
0b42f033	132	MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_LAN9303);
d3b8c049 AL	133
d3b8c049 AL	134	module_dsa_tag_driver(lan9303_netdev_ops);