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[net-next,1/3] net: dsa: vsc73xx: implement transmit via control interface

Message ID 20241020205452.2660042-1-paweldembicki@gmail.com (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
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Series [net-next,1/3] net: dsa: vsc73xx: implement transmit via control interface | expand

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Commit Message

Pawel Dembicki Oct. 20, 2024, 8:54 p.m. UTC
Some types of packets can be forwarded only to and from the PI/SI
interface. For more information, see Chapter 2.7.1 (CPU Forwarding) in
the datasheet.

This patch implements the routines required for link-local transmission.
This kind of traffic can't be transferred through the RGMII interface in
vsc73xx.

It uses a method similar to the sja1005 driver, where the DSA tagger
checks if the packet is link-local and uses a special deferred transmit
route for that kind of packet.

The vsc73xx uses an "Internal Frame Header" (IFH) in communication via the
PI/SI interface. Every packet must be prefixed with an IFH. The hardware
fixes the checksums, so there's no need to calculate the FCS in the
driver.

Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>
---
 drivers/net/dsa/vitesse-vsc73xx-core.c | 172 +++++++++++++++++++++++++
 drivers/net/dsa/vitesse-vsc73xx.h      |   1 +
 include/linux/dsa/vsc73xx.h            |  20 +++
 net/dsa/tag_vsc73xx_8021q.c            |  73 +++++++++++
 4 files changed, 266 insertions(+)
 create mode 100644 include/linux/dsa/vsc73xx.h

Comments

Vladimir Oltean Oct. 21, 2024, 12:07 p.m. UTC | #1
On Sun, Oct 20, 2024 at 10:54:50PM +0200, Pawel Dembicki wrote:
> Some types of packets can be forwarded only to and from the PI/SI
> interface. For more information, see Chapter 2.7.1 (CPU Forwarding) in
> the datasheet.
> 
> This patch implements the routines required for link-local transmission.
> This kind of traffic can't be transferred through the RGMII interface in
> vsc73xx.
> 
> It uses a method similar to the sja1005 driver, where the DSA tagger
> checks if the packet is link-local and uses a special deferred transmit
> route for that kind of packet.
> 
> The vsc73xx uses an "Internal Frame Header" (IFH) in communication via the
> PI/SI interface. Every packet must be prefixed with an IFH. The hardware
> fixes the checksums, so there's no need to calculate the FCS in the
> driver.
> 
> Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>
> ---
>  drivers/net/dsa/vitesse-vsc73xx-core.c | 172 +++++++++++++++++++++++++
>  drivers/net/dsa/vitesse-vsc73xx.h      |   1 +
>  include/linux/dsa/vsc73xx.h            |  20 +++
>  net/dsa/tag_vsc73xx_8021q.c            |  73 +++++++++++
>  4 files changed, 266 insertions(+)
>  create mode 100644 include/linux/dsa/vsc73xx.h
> 
> diff --git a/drivers/net/dsa/vitesse-vsc73xx-core.c b/drivers/net/dsa/vitesse-vsc73xx-core.c
> index f18aa321053d..21ab3f214490 100644
> --- a/drivers/net/dsa/vitesse-vsc73xx-core.c
> +++ b/drivers/net/dsa/vitesse-vsc73xx-core.c
> @@ -73,6 +73,9 @@
>  #define VSC73XX_CAT_PR_USR_PRIO	0x75
>  #define VSC73XX_CAT_VLAN_MISC	0x79
>  #define VSC73XX_CAT_PORT_VLAN	0x7a
> +#define VSC73XX_CPUTXDAT	0xc0
> +#define VSC73XX_MISCFIFO	0xc4
> +#define VSC73XX_MISCSTAT	0xc8
>  #define VSC73XX_Q_MISC_CONF	0xdf
>  
>  /* MAC_CFG register bits */
> @@ -166,6 +169,14 @@
>  #define VSC73XX_CAT_PORT_VLAN_VLAN_USR_PRIO GENMASK(14, 12)
>  #define VSC73XX_CAT_PORT_VLAN_VLAN_VID GENMASK(11, 0)
>  
> +/* MISCFIFO Miscellaneous Control Register */
> +#define VSC73XX_MISCFIFO_REWIND_CPU_TX	BIT(1)
> +#define VSC73XX_MISCFIFO_CPU_TX		BIT(0)
> +
> +/* MISCSTAT Miscellaneous Status */
> +#define VSC73XX_MISCSTAT_CPU_TX_DATA_PENDING	BIT(8)
> +#define VSC73XX_MISCSTAT_CPU_TX_DATA_OVERFLOW	BIT(7)
> +
>  /* Frame analyzer block 2 registers */
>  #define VSC73XX_STORMLIMIT	0x02
>  #define VSC73XX_ADVLEARN	0x03
> @@ -363,6 +374,9 @@
>  #define VSC73XX_MDIO_POLL_SLEEP_US	5
>  #define VSC73XX_POLL_TIMEOUT_US		10000
>  
> +#define VSC73XX_IFH_MAGIC		0x52
> +#define VSC73XX_IFH_SIZE		8
> +
>  struct vsc73xx_counter {
>  	u8 counter;
>  	const char *name;
> @@ -375,6 +389,31 @@ struct vsc73xx_fdb {
>  	bool valid;
>  };
>  
> +/* Internal frame header structure */
> +struct vsc73xx_ifh {
> +	union {
> +		u32 datah;
> +		struct {
> +		u32 wt:1, /* Frame was tagged but tag has removed from frame */
> +		    : 1,
> +		    frame_length:14, /* Frame Length including CRC */
> +		    : 11,
> +		    port:5; /* SRC port of switch */

Please indent the struct field members.

> +		};
> +	};
> +	union {
> +		u32 datal;

Is the union with datah/datal actually useful in any way? Just a comment
about high word/low word should suffice?

Is there any field that crosses the word boundary? Or is the IFH nicely
arranged?

Does CPU endianness affect the correct bit layout?

> +		struct {
> +		u32 vid:16, /* VLAN ID */
> +		    : 3,
> +		    magic:9, /* IFH magic field */
> +		    lpa:1, /* SMAC is subject of learning */
> +		    : 1,
> +		    priority:2; /* Switch categorizer assigned priority */
> +		};
> +	};
> +};

__packed

> +
>  /* Counters are named according to the MIB standards where applicable.
>   * Some counters are custom, non-standard. The standard counters are
>   * named in accordance with RFC2819, RFC2021 and IEEE Std 802.3-2002 Annex
> @@ -683,6 +722,133 @@ static int vsc73xx_phy_write(struct dsa_switch *ds, int phy, int regnum,
>  	return 0;
>  }
>  
> +static int vsc73xx_tx_fifo_busy_check(struct vsc73xx *vsc, int port)
> +{
> +	int ret, err;
> +	u32 val;
> +
> +	ret = read_poll_timeout(vsc73xx_read, err,
> +				err < 0 ||
> +				!(val & VSC73XX_MISCSTAT_CPU_TX_DATA_PENDING),
> +				VSC73XX_POLL_SLEEP_US,
> +				VSC73XX_POLL_TIMEOUT_US, false, vsc,
> +				VSC73XX_BLOCK_MAC, port, VSC73XX_MISCSTAT,
> +				&val);
> +	if (ret)
> +		return ret;
> +	return err;
> +}
> +
> +static int
> +vsc73xx_write_tx_fifo(struct vsc73xx *vsc, int port, u32 data0, u32 data1)
> +{
> +	vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_CPUTXDAT, data0);
> +	vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_CPUTXDAT, data1);
> +
> +	return vsc73xx_tx_fifo_busy_check(vsc, port);
> +}
> +
> +static int
> +vsc73xx_inject_frame(struct vsc73xx *vsc, int port, struct sk_buff *skb)
> +{
> +	struct vsc73xx_ifh *ifh;
> +	u32 length, i, count;
> +	u32 *buf;
> +	int ret;
> +
> +	if (skb->len + VSC73XX_IFH_SIZE < 64)
> +		length = 64;
> +	else
> +		length = skb->len + VSC73XX_IFH_SIZE;

length = min_t(u32, 64, skb->len + VSC73XX_IFH_SIZE)?
Also, what does 64 represent? ETH_ZLEN + ?

> +
> +	count = DIV_ROUND_UP(length, 8);
> +	buf = kzalloc(count * 8, GFP_KERNEL);

this can return NULL

> +	memset(buf, 0, sizeof(buf));
> +
> +	ifh = (struct vsc73xx_ifh *)buf;
> +	ifh->frame_length = skb->len;
> +	ifh->magic = VSC73XX_IFH_MAGIC;
> +
> +	skb_copy_and_csum_dev(skb, (u8 *)(buf + 2));

Do you really _have_ to allocate dynamically a buffer and copy the skb
to it? Can't you write_tx_fifo() based on a pointer from skb->data, and
allocate the IFH as a separate on-stack structure?

For the checksum calculation, you could add the same logic as ocelot_defer_xmit():

	if (skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_help(skb))
		return NULL;

> +
> +	for (i = 0; i < count; i++) {
> +		ret = vsc73xx_write_tx_fifo(vsc, port, buf[2 * i],
> +					    buf[2 * i + 1]);
> +		if (ret) {
> +			/* Clear buffer after error */
> +			vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port,
> +					    VSC73XX_MISCFIFO,
> +					    VSC73XX_MISCFIFO_REWIND_CPU_TX,
> +					    VSC73XX_MISCFIFO_REWIND_CPU_TX);
> +			goto err;
> +		}
> +	}
> +
> +	vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_MISCFIFO,
> +		      VSC73XX_MISCFIFO_CPU_TX);
> +
> +	skb_tx_timestamp(skb);

When is the packet transmission actually started? At VSC73XX_MISCFIFO_CPU_TX
time? skb_tx_timestamp() should be done prior to that. PHY TX
timestamping is also hooked into this call, and will be completely
broken if it is racing with the packet transmission.

> +
> +	skb->dev->stats.tx_packets++;
> +	skb->dev->stats.tx_bytes += skb->len;
> +err:
> +	kfree(buf);
> +	return ret;
> +}
> +
> +#define work_to_xmit_work(w) \
> +		container_of((w), struct vsc73xx_deferred_xmit_work, work)
> +
> +static void vsc73xx_deferred_xmit(struct kthread_work *work)
> +{
> +	struct vsc73xx_deferred_xmit_work *xmit_work = work_to_xmit_work(work);
> +	struct dsa_switch *ds = xmit_work->dp->ds;
> +	struct sk_buff *skb = xmit_work->skb;
> +	int port = xmit_work->dp->index;
> +	struct vsc73xx *vsc = ds->priv;
> +	int ret;
> +
> +	if (vsc73xx_tx_fifo_busy_check(vsc, port)) {
> +		dev_err(vsc->dev, "port %d failed to inject skb\n",
> +			port);
> +
> +		/* Clear buffer after error */
> +		vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port,
> +				    VSC73XX_MISCFIFO,
> +				    VSC73XX_MISCFIFO_REWIND_CPU_TX,
> +				    VSC73XX_MISCFIFO_REWIND_CPU_TX);
> +
> +		kfree_skb(skb);
> +		return;
> +	}
> +
> +	ret = vsc73xx_inject_frame(vsc, port, skb);
> +

extraneous blank line

> +	if (ret) {
> +		dev_err(vsc->dev, "port %d failed to inject skb\n",

dev_err_ratelimited(... %pe, ERR_PTR(ret))?

> +			port);
> +		return;
> +	}

Is this hardware procedure completely reentrant (can it simultaneously
inject packets towards multiple ports) or should there be a spinlock
serializing the access?

> +
> +	consume_skb(skb);
> +	kfree(xmit_work);
> +}
Vadim Fedorenko Oct. 21, 2024, 9:41 p.m. UTC | #2
On 20/10/2024 21:54, Pawel Dembicki wrote:
> Some types of packets can be forwarded only to and from the PI/SI
> interface. For more information, see Chapter 2.7.1 (CPU Forwarding) in
> the datasheet.
> 
> This patch implements the routines required for link-local transmission.
> This kind of traffic can't be transferred through the RGMII interface in
> vsc73xx.
> 
> It uses a method similar to the sja1005 driver, where the DSA tagger
> checks if the packet is link-local and uses a special deferred transmit
> route for that kind of packet.
> 
> The vsc73xx uses an "Internal Frame Header" (IFH) in communication via the
> PI/SI interface. Every packet must be prefixed with an IFH. The hardware
> fixes the checksums, so there's no need to calculate the FCS in the
> driver.
> 
> Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>
> ---
>   drivers/net/dsa/vitesse-vsc73xx-core.c | 172 +++++++++++++++++++++++++
>   drivers/net/dsa/vitesse-vsc73xx.h      |   1 +
>   include/linux/dsa/vsc73xx.h            |  20 +++
>   net/dsa/tag_vsc73xx_8021q.c            |  73 +++++++++++
>   4 files changed, 266 insertions(+)
>   create mode 100644 include/linux/dsa/vsc73xx.h
> 
> diff --git a/drivers/net/dsa/vitesse-vsc73xx-core.c b/drivers/net/dsa/vitesse-vsc73xx-core.c
> index f18aa321053d..21ab3f214490 100644
> --- a/drivers/net/dsa/vitesse-vsc73xx-core.c
> +++ b/drivers/net/dsa/vitesse-vsc73xx-core.c
> @@ -73,6 +73,9 @@
>   #define VSC73XX_CAT_PR_USR_PRIO	0x75
>   #define VSC73XX_CAT_VLAN_MISC	0x79
>   #define VSC73XX_CAT_PORT_VLAN	0x7a
> +#define VSC73XX_CPUTXDAT	0xc0
> +#define VSC73XX_MISCFIFO	0xc4
> +#define VSC73XX_MISCSTAT	0xc8
>   #define VSC73XX_Q_MISC_CONF	0xdf
>   
>   /* MAC_CFG register bits */
> @@ -166,6 +169,14 @@
>   #define VSC73XX_CAT_PORT_VLAN_VLAN_USR_PRIO GENMASK(14, 12)
>   #define VSC73XX_CAT_PORT_VLAN_VLAN_VID GENMASK(11, 0)
>   
> +/* MISCFIFO Miscellaneous Control Register */
> +#define VSC73XX_MISCFIFO_REWIND_CPU_TX	BIT(1)
> +#define VSC73XX_MISCFIFO_CPU_TX		BIT(0)
> +
> +/* MISCSTAT Miscellaneous Status */
> +#define VSC73XX_MISCSTAT_CPU_TX_DATA_PENDING	BIT(8)
> +#define VSC73XX_MISCSTAT_CPU_TX_DATA_OVERFLOW	BIT(7)
> +
>   /* Frame analyzer block 2 registers */
>   #define VSC73XX_STORMLIMIT	0x02
>   #define VSC73XX_ADVLEARN	0x03
> @@ -363,6 +374,9 @@
>   #define VSC73XX_MDIO_POLL_SLEEP_US	5
>   #define VSC73XX_POLL_TIMEOUT_US		10000
>   
> +#define VSC73XX_IFH_MAGIC		0x52
> +#define VSC73XX_IFH_SIZE		8
> +
>   struct vsc73xx_counter {
>   	u8 counter;
>   	const char *name;
> @@ -375,6 +389,31 @@ struct vsc73xx_fdb {
>   	bool valid;
>   };
>   
> +/* Internal frame header structure */
> +struct vsc73xx_ifh {
> +	union {
> +		u32 datah;
> +		struct {
> +		u32 wt:1, /* Frame was tagged but tag has removed from frame */
> +		    : 1,
> +		    frame_length:14, /* Frame Length including CRC */
> +		    : 11,
> +		    port:5; /* SRC port of switch */
> +		};
> +	};
> +	union {
> +		u32 datal;
> +		struct {
> +		u32 vid:16, /* VLAN ID */
> +		    : 3,
> +		    magic:9, /* IFH magic field */
> +		    lpa:1, /* SMAC is subject of learning */
> +		    : 1,
> +		    priority:2; /* Switch categorizer assigned priority */
> +		};
> +	};
> +};
> +
>   /* Counters are named according to the MIB standards where applicable.
>    * Some counters are custom, non-standard. The standard counters are
>    * named in accordance with RFC2819, RFC2021 and IEEE Std 802.3-2002 Annex
> @@ -683,6 +722,133 @@ static int vsc73xx_phy_write(struct dsa_switch *ds, int phy, int regnum,
>   	return 0;
>   }
>   
> +static int vsc73xx_tx_fifo_busy_check(struct vsc73xx *vsc, int port)
> +{
> +	int ret, err;
> +	u32 val;
> +
> +	ret = read_poll_timeout(vsc73xx_read, err,
> +				err < 0 ||
> +				!(val & VSC73XX_MISCSTAT_CPU_TX_DATA_PENDING),
> +				VSC73XX_POLL_SLEEP_US,
> +				VSC73XX_POLL_TIMEOUT_US, false, vsc,
> +				VSC73XX_BLOCK_MAC, port, VSC73XX_MISCSTAT,
> +				&val);
> +	if (ret)
> +		return ret;
> +	return err;
> +}
> +
> +static int
> +vsc73xx_write_tx_fifo(struct vsc73xx *vsc, int port, u32 data0, u32 data1)
> +{
> +	vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_CPUTXDAT, data0);
> +	vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_CPUTXDAT, data1);
> +
> +	return vsc73xx_tx_fifo_busy_check(vsc, port);
> +}
> +
> +static int
> +vsc73xx_inject_frame(struct vsc73xx *vsc, int port, struct sk_buff *skb)
> +{
> +	struct vsc73xx_ifh *ifh;
> +	u32 length, i, count;
> +	u32 *buf;
> +	int ret;
> +
> +	if (skb->len + VSC73XX_IFH_SIZE < 64)
> +		length = 64;
> +	else
> +		length = skb->len + VSC73XX_IFH_SIZE;

This looks like open-coded length = max(64, skb->len + VSC73XX_IFH_SIZE)

> +
> +	count = DIV_ROUND_UP(length, 8);
> +	buf = kzalloc(count * 8, GFP_KERNEL);
> +	memset(buf, 0, sizeof(buf));

no need to memset, kzalloc initializes memory to zero

> +
> +	ifh = (struct vsc73xx_ifh *)buf;
> +	ifh->frame_length = skb->len;
> +	ifh->magic = VSC73XX_IFH_MAGIC;
> +
> +	skb_copy_and_csum_dev(skb, (u8 *)(buf + 2));
> +
> +	for (i = 0; i < count; i++) {
> +		ret = vsc73xx_write_tx_fifo(vsc, port, buf[2 * i],
> +					    buf[2 * i + 1]);
> +		if (ret) {
> +			/* Clear buffer after error */
> +			vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port,
> +					    VSC73XX_MISCFIFO,
> +					    VSC73XX_MISCFIFO_REWIND_CPU_TX,
> +					    VSC73XX_MISCFIFO_REWIND_CPU_TX);
> +			goto err;
> +		}
> +	}
> +
> +	vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_MISCFIFO,
> +		      VSC73XX_MISCFIFO_CPU_TX);
> +
> +	skb_tx_timestamp(skb);
> +
> +	skb->dev->stats.tx_packets++;
> +	skb->dev->stats.tx_bytes += skb->len;
> +err:
> +	kfree(buf);
> +	return ret;
> +}
> +
> +#define work_to_xmit_work(w) \
> +		container_of((w), struct vsc73xx_deferred_xmit_work, work)
> +
> +static void vsc73xx_deferred_xmit(struct kthread_work *work)
> +{
> +	struct vsc73xx_deferred_xmit_work *xmit_work = work_to_xmit_work(work);
> +	struct dsa_switch *ds = xmit_work->dp->ds;
> +	struct sk_buff *skb = xmit_work->skb;
> +	int port = xmit_work->dp->index;
> +	struct vsc73xx *vsc = ds->priv;
> +	int ret;
> +
> +	if (vsc73xx_tx_fifo_busy_check(vsc, port)) {
> +		dev_err(vsc->dev, "port %d failed to inject skb\n",
> +			port);
> +
> +		/* Clear buffer after error */
> +		vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port,
> +				    VSC73XX_MISCFIFO,
> +				    VSC73XX_MISCFIFO_REWIND_CPU_TX,
> +				    VSC73XX_MISCFIFO_REWIND_CPU_TX);
> +
> +		kfree_skb(skb);
> +		return;
> +	}
> +
> +	ret = vsc73xx_inject_frame(vsc, port, skb);
> +
> +	if (ret) {
> +		dev_err(vsc->dev, "port %d failed to inject skb\n",
> +			port);
> +		return;
> +	}
> +
> +	consume_skb(skb);
> +	kfree(xmit_work);
> +}
> +
> +static int
> +vsc73xx_connect_tag_protocol(struct dsa_switch *ds, enum dsa_tag_protocol proto)
> +{
> +	struct vsc73xx_8021q_tagger_data *tagger_data;
> +
> +	switch (proto) {
> +	case DSA_TAG_PROTO_VSC73XX_8021Q:
> +		tagger_data = ds->tagger_data;
> +		tagger_data->xmit_work_fn = vsc73xx_deferred_xmit;
> +		return 0;
> +	default:
> +		return -EPROTONOSUPPORT;
> +	}
> +}
> +
>   static enum dsa_tag_protocol vsc73xx_get_tag_protocol(struct dsa_switch *ds,
>   						      int port,
>   						      enum dsa_tag_protocol mp)
> @@ -1026,6 +1192,11 @@ static void vsc73xx_init_port(struct vsc73xx *vsc, int port)
>   		      VSC73XX_CAT_DROP,
>   		      VSC73XX_CAT_DROP_FWD_PAUSE_ENA);
>   
> +	/* Allow switch to recalculate CRC of CPU packets */
> +	vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_TXUPDCFG,
> +			    VSC73XX_TXUPDCFG_TX_UPDATE_CRC_CPU_ENA,
> +			    VSC73XX_TXUPDCFG_TX_UPDATE_CRC_CPU_ENA);
> +
>   	/* Clear all counters */
>   	vsc73xx_write(vsc, VSC73XX_BLOCK_MAC,
>   		      port, VSC73XX_C_RX0, 0);
> @@ -2217,6 +2388,7 @@ static const struct phylink_mac_ops vsc73xx_phylink_mac_ops = {
>   
>   static const struct dsa_switch_ops vsc73xx_ds_ops = {
>   	.get_tag_protocol = vsc73xx_get_tag_protocol,
> +	.connect_tag_protocol = vsc73xx_connect_tag_protocol,
>   	.setup = vsc73xx_setup,
>   	.teardown = vsc73xx_teardown,
>   	.phy_read = vsc73xx_phy_read,
> diff --git a/drivers/net/dsa/vitesse-vsc73xx.h b/drivers/net/dsa/vitesse-vsc73xx.h
> index 3c30e143c14f..bf55a20f07f3 100644
> --- a/drivers/net/dsa/vitesse-vsc73xx.h
> +++ b/drivers/net/dsa/vitesse-vsc73xx.h
> @@ -2,6 +2,7 @@
>   #include <linux/device.h>
>   #include <linux/etherdevice.h>
>   #include <linux/gpio/driver.h>
> +#include <linux/dsa/vsc73xx.h>
>   
>   /* The VSC7395 switch chips have 5+1 ports which means 5 ordinary ports and
>    * a sixth CPU port facing the processor with an RGMII interface. These ports
> diff --git a/include/linux/dsa/vsc73xx.h b/include/linux/dsa/vsc73xx.h
> new file mode 100644
> index 000000000000..901eeb1da120
> --- /dev/null
> +++ b/include/linux/dsa/vsc73xx.h
> @@ -0,0 +1,20 @@
> +/* SPDX-License-Identifier: GPL-2.0
> + * Copyright (c) 2024, Pawel Dembicki <paweldembicki@gmail.com>
> + */
> +
> +/* Included by drivers/net/dsa/vitesse-vsc73xx.h and net/dsa/tag_vsc73xx_8021q.c */
> +
> +#ifndef _NET_DSA_VSC73XX_H
> +#define _NET_DSA_VSC73XX_H
> +
> +struct vsc73xx_deferred_xmit_work {
> +	struct dsa_port *dp;
> +	struct sk_buff *skb;
> +	struct kthread_work work;
> +};
> +
> +struct vsc73xx_8021q_tagger_data {
> +	void (*xmit_work_fn)(struct kthread_work *work);
> +};
> +
> +#endif /* _NET_DSA_VSC73XX_H */
> diff --git a/net/dsa/tag_vsc73xx_8021q.c b/net/dsa/tag_vsc73xx_8021q.c
> index af121a9aff7f..d1d7a860a76e 100644
> --- a/net/dsa/tag_vsc73xx_8021q.c
> +++ b/net/dsa/tag_vsc73xx_8021q.c
> @@ -2,20 +2,61 @@
>   /* Copyright (C) 2024 Pawel Dembicki <paweldembicki@gmail.com>
>    */
>   #include <linux/dsa/8021q.h>
> +#include <linux/dsa/vsc73xx.h>
>   
>   #include "tag.h"
>   #include "tag_8021q.h"
>   
>   #define VSC73XX_8021Q_NAME "vsc73xx-8021q"
>   
> +struct vsc73xx_8021q_tagger_private {
> +	struct vsc73xx_8021q_tagger_data data; /* Must be first */
> +	struct kthread_worker *xmit_worker;
> +};
> +
> +static struct sk_buff *vsc73xx_defer_xmit(struct dsa_port *dp, struct sk_buff *skb)
> +{
> +	struct vsc73xx_8021q_tagger_private *priv = dp->ds->tagger_data;
> +	struct vsc73xx_8021q_tagger_data *data = &priv->data;
> +	void (*xmit_work_fn)(struct kthread_work *work);
> +	struct vsc73xx_deferred_xmit_work *xmit_work;
> +	struct kthread_worker *xmit_worker;
> +
> +	xmit_work_fn = data->xmit_work_fn;
> +	xmit_worker = priv->xmit_worker;
> +
> +	if (!xmit_work_fn || !xmit_worker)
> +		return NULL;
> +
> +	xmit_work = kzalloc(sizeof(*xmit_work), GFP_ATOMIC);
> +	if (!xmit_work)
> +		return NULL;
> +
> +	/* Calls vsc73xx_port_deferred_xmit in vitesse-vsc73xx-core.c */
> +	kthread_init_work(&xmit_work->work, xmit_work_fn);
> +	/* Increase refcount so the kfree_skb in dsa_slave_xmit
> +	 * won't really free the packet.
> +	 */
> +	xmit_work->dp = dp;
> +	xmit_work->skb = skb_get(skb);
> +
> +	kthread_queue_work(xmit_worker, &xmit_work->work);
> +
> +	return NULL;
> +}
> +
>   static struct sk_buff *
>   vsc73xx_xmit(struct sk_buff *skb, struct net_device *netdev)
>   {
>   	struct dsa_port *dp = dsa_user_to_port(netdev);
>   	u16 queue_mapping = skb_get_queue_mapping(skb);
>   	u16 tx_vid = dsa_tag_8021q_standalone_vid(dp);
> +	struct ethhdr *hdr = eth_hdr(skb);
>   	u8 pcp;
>   
> +	if (is_link_local_ether_addr(hdr->h_dest))
> +		return vsc73xx_defer_xmit(dp, skb);
> +
>   	if (skb->offload_fwd_mark) {
>   		unsigned int bridge_num = dsa_port_bridge_num_get(dp);
>   		struct net_device *br = dsa_port_bridge_dev_get(dp);
> @@ -52,11 +93,43 @@ vsc73xx_rcv(struct sk_buff *skb, struct net_device *netdev)
>   	return skb;
>   }
>   
> +static void vsc73xx_disconnect(struct dsa_switch *ds)
> +{
> +	struct vsc73xx_8021q_tagger_private *priv = ds->tagger_data;
> +
> +	kthread_destroy_worker(priv->xmit_worker);
> +	kfree(priv);
> +	ds->tagger_data = NULL;
> +}
> +
> +static int vsc73xx_connect(struct dsa_switch *ds)
> +{
> +	struct vsc73xx_8021q_tagger_private *priv;
> +	int err;
> +
> +	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->xmit_worker = kthread_create_worker(0, "vsc73xx_xmit");
> +	if (IS_ERR(priv->xmit_worker)) {
> +		err = PTR_ERR(priv->xmit_worker);
> +		kfree(priv);
> +		return err;
> +	}
> +
> +	ds->tagger_data = priv;
> +
> +	return 0;
> +}
> +
>   static const struct dsa_device_ops vsc73xx_8021q_netdev_ops = {
>   	.name			= VSC73XX_8021Q_NAME,
>   	.proto			= DSA_TAG_PROTO_VSC73XX_8021Q,
>   	.xmit			= vsc73xx_xmit,
>   	.rcv			= vsc73xx_rcv,
> +	.connect		= vsc73xx_connect,
> +	.disconnect		= vsc73xx_disconnect,
>   	.needed_headroom	= VLAN_HLEN,
>   	.promisc_on_conduit	= true,
>   };
kernel test robot Oct. 22, 2024, 12:46 a.m. UTC | #3
Hi Pawel,

kernel test robot noticed the following build warnings:

[auto build test WARNING on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Pawel-Dembicki/net-dsa-vsc73xx-implement-packet-reception-via-control-interface/20241021-050041
base:   net-next/main
patch link:    https://lore.kernel.org/r/20241020205452.2660042-1-paweldembicki%40gmail.com
patch subject: [PATCH net-next 1/3] net: dsa: vsc73xx: implement transmit via control interface
config: m68k-allmodconfig (https://download.01.org/0day-ci/archive/20241022/202410220836.TtUmbpFx-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 14.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241022/202410220836.TtUmbpFx-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410220836.TtUmbpFx-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from include/linux/string.h:64,
                    from include/linux/bitmap.h:13,
                    from include/linux/cpumask.h:12,
                    from include/linux/smp.h:13,
                    from include/linux/lockdep.h:14,
                    from include/linux/spinlock.h:63,
                    from include/linux/mmzone.h:8,
                    from include/linux/gfp.h:7,
                    from include/linux/umh.h:4,
                    from include/linux/kmod.h:9,
                    from include/linux/module.h:17,
                    from drivers/net/dsa/vitesse-vsc73xx-core.c:18:
   drivers/net/dsa/vitesse-vsc73xx-core.c: In function 'vsc73xx_inject_frame':
>> drivers/net/dsa/vitesse-vsc73xx-core.c:766:30: warning: argument to 'sizeof' in '__builtin_memset' call is the same expression as the destination; did you mean to dereference it? [-Wsizeof-pointer-memaccess]
     766 |         memset(buf, 0, sizeof(buf));
         |                              ^
   arch/m68k/include/asm/string.h:49:48: note: in definition of macro 'memset'
      49 | #define memset(d, c, n) __builtin_memset(d, c, n)
         |                                                ^

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for GET_FREE_REGION
   Depends on [n]: SPARSEMEM [=n]
   Selected by [m]:
   - RESOURCE_KUNIT_TEST [=m] && RUNTIME_TESTING_MENU [=y] && KUNIT [=m]


vim +766 drivers/net/dsa/vitesse-vsc73xx-core.c

   750	
   751	static int
   752	vsc73xx_inject_frame(struct vsc73xx *vsc, int port, struct sk_buff *skb)
   753	{
   754		struct vsc73xx_ifh *ifh;
   755		u32 length, i, count;
   756		u32 *buf;
   757		int ret;
   758	
   759		if (skb->len + VSC73XX_IFH_SIZE < 64)
   760			length = 64;
   761		else
   762			length = skb->len + VSC73XX_IFH_SIZE;
   763	
   764		count = DIV_ROUND_UP(length, 8);
   765		buf = kzalloc(count * 8, GFP_KERNEL);
 > 766		memset(buf, 0, sizeof(buf));
   767	
   768		ifh = (struct vsc73xx_ifh *)buf;
   769		ifh->frame_length = skb->len;
   770		ifh->magic = VSC73XX_IFH_MAGIC;
   771	
   772		skb_copy_and_csum_dev(skb, (u8 *)(buf + 2));
   773	
   774		for (i = 0; i < count; i++) {
   775			ret = vsc73xx_write_tx_fifo(vsc, port, buf[2 * i],
   776						    buf[2 * i + 1]);
   777			if (ret) {
   778				/* Clear buffer after error */
   779				vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port,
   780						    VSC73XX_MISCFIFO,
   781						    VSC73XX_MISCFIFO_REWIND_CPU_TX,
   782						    VSC73XX_MISCFIFO_REWIND_CPU_TX);
   783				goto err;
   784			}
   785		}
   786	
   787		vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_MISCFIFO,
   788			      VSC73XX_MISCFIFO_CPU_TX);
   789	
   790		skb_tx_timestamp(skb);
   791	
   792		skb->dev->stats.tx_packets++;
   793		skb->dev->stats.tx_bytes += skb->len;
   794	err:
   795		kfree(buf);
   796		return ret;
   797	}
   798
kernel test robot Oct. 22, 2024, 3:11 a.m. UTC | #4
Hi Pawel,

kernel test robot noticed the following build warnings:

[auto build test WARNING on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Pawel-Dembicki/net-dsa-vsc73xx-implement-packet-reception-via-control-interface/20241021-050041
base:   net-next/main
patch link:    https://lore.kernel.org/r/20241020205452.2660042-1-paweldembicki%40gmail.com
patch subject: [PATCH net-next 1/3] net: dsa: vsc73xx: implement transmit via control interface
config: openrisc-allyesconfig (https://download.01.org/0day-ci/archive/20241022/202410221001.KrzTEU3A-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 14.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241022/202410221001.KrzTEU3A-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410221001.KrzTEU3A-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/net/dsa/vitesse-vsc73xx-core.c: In function 'vsc73xx_inject_frame':
>> drivers/net/dsa/vitesse-vsc73xx-core.c:766:30: warning: argument to 'sizeof' in 'memset' call is the same expression as the destination; did you mean to dereference it? [-Wsizeof-pointer-memaccess]
     766 |         memset(buf, 0, sizeof(buf));
         |                              ^

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for GET_FREE_REGION
   Depends on [n]: SPARSEMEM [=n]
   Selected by [y]:
   - RESOURCE_KUNIT_TEST [=y] && RUNTIME_TESTING_MENU [=y] && KUNIT [=y]


vim +766 drivers/net/dsa/vitesse-vsc73xx-core.c

   750	
   751	static int
   752	vsc73xx_inject_frame(struct vsc73xx *vsc, int port, struct sk_buff *skb)
   753	{
   754		struct vsc73xx_ifh *ifh;
   755		u32 length, i, count;
   756		u32 *buf;
   757		int ret;
   758	
   759		if (skb->len + VSC73XX_IFH_SIZE < 64)
   760			length = 64;
   761		else
   762			length = skb->len + VSC73XX_IFH_SIZE;
   763	
   764		count = DIV_ROUND_UP(length, 8);
   765		buf = kzalloc(count * 8, GFP_KERNEL);
 > 766		memset(buf, 0, sizeof(buf));
   767	
   768		ifh = (struct vsc73xx_ifh *)buf;
   769		ifh->frame_length = skb->len;
   770		ifh->magic = VSC73XX_IFH_MAGIC;
   771	
   772		skb_copy_and_csum_dev(skb, (u8 *)(buf + 2));
   773	
   774		for (i = 0; i < count; i++) {
   775			ret = vsc73xx_write_tx_fifo(vsc, port, buf[2 * i],
   776						    buf[2 * i + 1]);
   777			if (ret) {
   778				/* Clear buffer after error */
   779				vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port,
   780						    VSC73XX_MISCFIFO,
   781						    VSC73XX_MISCFIFO_REWIND_CPU_TX,
   782						    VSC73XX_MISCFIFO_REWIND_CPU_TX);
   783				goto err;
   784			}
   785		}
   786	
   787		vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_MISCFIFO,
   788			      VSC73XX_MISCFIFO_CPU_TX);
   789	
   790		skb_tx_timestamp(skb);
   791	
   792		skb->dev->stats.tx_packets++;
   793		skb->dev->stats.tx_bytes += skb->len;
   794	err:
   795		kfree(buf);
   796		return ret;
   797	}
   798
diff mbox series

Patch

diff --git a/drivers/net/dsa/vitesse-vsc73xx-core.c b/drivers/net/dsa/vitesse-vsc73xx-core.c
index f18aa321053d..21ab3f214490 100644
--- a/drivers/net/dsa/vitesse-vsc73xx-core.c
+++ b/drivers/net/dsa/vitesse-vsc73xx-core.c
@@ -73,6 +73,9 @@ 
 #define VSC73XX_CAT_PR_USR_PRIO	0x75
 #define VSC73XX_CAT_VLAN_MISC	0x79
 #define VSC73XX_CAT_PORT_VLAN	0x7a
+#define VSC73XX_CPUTXDAT	0xc0
+#define VSC73XX_MISCFIFO	0xc4
+#define VSC73XX_MISCSTAT	0xc8
 #define VSC73XX_Q_MISC_CONF	0xdf
 
 /* MAC_CFG register bits */
@@ -166,6 +169,14 @@ 
 #define VSC73XX_CAT_PORT_VLAN_VLAN_USR_PRIO GENMASK(14, 12)
 #define VSC73XX_CAT_PORT_VLAN_VLAN_VID GENMASK(11, 0)
 
+/* MISCFIFO Miscellaneous Control Register */
+#define VSC73XX_MISCFIFO_REWIND_CPU_TX	BIT(1)
+#define VSC73XX_MISCFIFO_CPU_TX		BIT(0)
+
+/* MISCSTAT Miscellaneous Status */
+#define VSC73XX_MISCSTAT_CPU_TX_DATA_PENDING	BIT(8)
+#define VSC73XX_MISCSTAT_CPU_TX_DATA_OVERFLOW	BIT(7)
+
 /* Frame analyzer block 2 registers */
 #define VSC73XX_STORMLIMIT	0x02
 #define VSC73XX_ADVLEARN	0x03
@@ -363,6 +374,9 @@ 
 #define VSC73XX_MDIO_POLL_SLEEP_US	5
 #define VSC73XX_POLL_TIMEOUT_US		10000
 
+#define VSC73XX_IFH_MAGIC		0x52
+#define VSC73XX_IFH_SIZE		8
+
 struct vsc73xx_counter {
 	u8 counter;
 	const char *name;
@@ -375,6 +389,31 @@  struct vsc73xx_fdb {
 	bool valid;
 };
 
+/* Internal frame header structure */
+struct vsc73xx_ifh {
+	union {
+		u32 datah;
+		struct {
+		u32 wt:1, /* Frame was tagged but tag has removed from frame */
+		    : 1,
+		    frame_length:14, /* Frame Length including CRC */
+		    : 11,
+		    port:5; /* SRC port of switch */
+		};
+	};
+	union {
+		u32 datal;
+		struct {
+		u32 vid:16, /* VLAN ID */
+		    : 3,
+		    magic:9, /* IFH magic field */
+		    lpa:1, /* SMAC is subject of learning */
+		    : 1,
+		    priority:2; /* Switch categorizer assigned priority */
+		};
+	};
+};
+
 /* Counters are named according to the MIB standards where applicable.
  * Some counters are custom, non-standard. The standard counters are
  * named in accordance with RFC2819, RFC2021 and IEEE Std 802.3-2002 Annex
@@ -683,6 +722,133 @@  static int vsc73xx_phy_write(struct dsa_switch *ds, int phy, int regnum,
 	return 0;
 }
 
+static int vsc73xx_tx_fifo_busy_check(struct vsc73xx *vsc, int port)
+{
+	int ret, err;
+	u32 val;
+
+	ret = read_poll_timeout(vsc73xx_read, err,
+				err < 0 ||
+				!(val & VSC73XX_MISCSTAT_CPU_TX_DATA_PENDING),
+				VSC73XX_POLL_SLEEP_US,
+				VSC73XX_POLL_TIMEOUT_US, false, vsc,
+				VSC73XX_BLOCK_MAC, port, VSC73XX_MISCSTAT,
+				&val);
+	if (ret)
+		return ret;
+	return err;
+}
+
+static int
+vsc73xx_write_tx_fifo(struct vsc73xx *vsc, int port, u32 data0, u32 data1)
+{
+	vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_CPUTXDAT, data0);
+	vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_CPUTXDAT, data1);
+
+	return vsc73xx_tx_fifo_busy_check(vsc, port);
+}
+
+static int
+vsc73xx_inject_frame(struct vsc73xx *vsc, int port, struct sk_buff *skb)
+{
+	struct vsc73xx_ifh *ifh;
+	u32 length, i, count;
+	u32 *buf;
+	int ret;
+
+	if (skb->len + VSC73XX_IFH_SIZE < 64)
+		length = 64;
+	else
+		length = skb->len + VSC73XX_IFH_SIZE;
+
+	count = DIV_ROUND_UP(length, 8);
+	buf = kzalloc(count * 8, GFP_KERNEL);
+	memset(buf, 0, sizeof(buf));
+
+	ifh = (struct vsc73xx_ifh *)buf;
+	ifh->frame_length = skb->len;
+	ifh->magic = VSC73XX_IFH_MAGIC;
+
+	skb_copy_and_csum_dev(skb, (u8 *)(buf + 2));
+
+	for (i = 0; i < count; i++) {
+		ret = vsc73xx_write_tx_fifo(vsc, port, buf[2 * i],
+					    buf[2 * i + 1]);
+		if (ret) {
+			/* Clear buffer after error */
+			vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port,
+					    VSC73XX_MISCFIFO,
+					    VSC73XX_MISCFIFO_REWIND_CPU_TX,
+					    VSC73XX_MISCFIFO_REWIND_CPU_TX);
+			goto err;
+		}
+	}
+
+	vsc73xx_write(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_MISCFIFO,
+		      VSC73XX_MISCFIFO_CPU_TX);
+
+	skb_tx_timestamp(skb);
+
+	skb->dev->stats.tx_packets++;
+	skb->dev->stats.tx_bytes += skb->len;
+err:
+	kfree(buf);
+	return ret;
+}
+
+#define work_to_xmit_work(w) \
+		container_of((w), struct vsc73xx_deferred_xmit_work, work)
+
+static void vsc73xx_deferred_xmit(struct kthread_work *work)
+{
+	struct vsc73xx_deferred_xmit_work *xmit_work = work_to_xmit_work(work);
+	struct dsa_switch *ds = xmit_work->dp->ds;
+	struct sk_buff *skb = xmit_work->skb;
+	int port = xmit_work->dp->index;
+	struct vsc73xx *vsc = ds->priv;
+	int ret;
+
+	if (vsc73xx_tx_fifo_busy_check(vsc, port)) {
+		dev_err(vsc->dev, "port %d failed to inject skb\n",
+			port);
+
+		/* Clear buffer after error */
+		vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port,
+				    VSC73XX_MISCFIFO,
+				    VSC73XX_MISCFIFO_REWIND_CPU_TX,
+				    VSC73XX_MISCFIFO_REWIND_CPU_TX);
+
+		kfree_skb(skb);
+		return;
+	}
+
+	ret = vsc73xx_inject_frame(vsc, port, skb);
+
+	if (ret) {
+		dev_err(vsc->dev, "port %d failed to inject skb\n",
+			port);
+		return;
+	}
+
+	consume_skb(skb);
+	kfree(xmit_work);
+}
+
+static int
+vsc73xx_connect_tag_protocol(struct dsa_switch *ds, enum dsa_tag_protocol proto)
+{
+	struct vsc73xx_8021q_tagger_data *tagger_data;
+
+	switch (proto) {
+	case DSA_TAG_PROTO_VSC73XX_8021Q:
+		tagger_data = ds->tagger_data;
+		tagger_data->xmit_work_fn = vsc73xx_deferred_xmit;
+		return 0;
+	default:
+		return -EPROTONOSUPPORT;
+	}
+}
+
 static enum dsa_tag_protocol vsc73xx_get_tag_protocol(struct dsa_switch *ds,
 						      int port,
 						      enum dsa_tag_protocol mp)
@@ -1026,6 +1192,11 @@  static void vsc73xx_init_port(struct vsc73xx *vsc, int port)
 		      VSC73XX_CAT_DROP,
 		      VSC73XX_CAT_DROP_FWD_PAUSE_ENA);
 
+	/* Allow switch to recalculate CRC of CPU packets */
+	vsc73xx_update_bits(vsc, VSC73XX_BLOCK_MAC, port, VSC73XX_TXUPDCFG,
+			    VSC73XX_TXUPDCFG_TX_UPDATE_CRC_CPU_ENA,
+			    VSC73XX_TXUPDCFG_TX_UPDATE_CRC_CPU_ENA);
+
 	/* Clear all counters */
 	vsc73xx_write(vsc, VSC73XX_BLOCK_MAC,
 		      port, VSC73XX_C_RX0, 0);
@@ -2217,6 +2388,7 @@  static const struct phylink_mac_ops vsc73xx_phylink_mac_ops = {
 
 static const struct dsa_switch_ops vsc73xx_ds_ops = {
 	.get_tag_protocol = vsc73xx_get_tag_protocol,
+	.connect_tag_protocol = vsc73xx_connect_tag_protocol,
 	.setup = vsc73xx_setup,
 	.teardown = vsc73xx_teardown,
 	.phy_read = vsc73xx_phy_read,
diff --git a/drivers/net/dsa/vitesse-vsc73xx.h b/drivers/net/dsa/vitesse-vsc73xx.h
index 3c30e143c14f..bf55a20f07f3 100644
--- a/drivers/net/dsa/vitesse-vsc73xx.h
+++ b/drivers/net/dsa/vitesse-vsc73xx.h
@@ -2,6 +2,7 @@ 
 #include <linux/device.h>
 #include <linux/etherdevice.h>
 #include <linux/gpio/driver.h>
+#include <linux/dsa/vsc73xx.h>
 
 /* The VSC7395 switch chips have 5+1 ports which means 5 ordinary ports and
  * a sixth CPU port facing the processor with an RGMII interface. These ports
diff --git a/include/linux/dsa/vsc73xx.h b/include/linux/dsa/vsc73xx.h
new file mode 100644
index 000000000000..901eeb1da120
--- /dev/null
+++ b/include/linux/dsa/vsc73xx.h
@@ -0,0 +1,20 @@ 
+/* SPDX-License-Identifier: GPL-2.0
+ * Copyright (c) 2024, Pawel Dembicki <paweldembicki@gmail.com>
+ */
+
+/* Included by drivers/net/dsa/vitesse-vsc73xx.h and net/dsa/tag_vsc73xx_8021q.c */
+
+#ifndef _NET_DSA_VSC73XX_H
+#define _NET_DSA_VSC73XX_H
+
+struct vsc73xx_deferred_xmit_work {
+	struct dsa_port *dp;
+	struct sk_buff *skb;
+	struct kthread_work work;
+};
+
+struct vsc73xx_8021q_tagger_data {
+	void (*xmit_work_fn)(struct kthread_work *work);
+};
+
+#endif /* _NET_DSA_VSC73XX_H */
diff --git a/net/dsa/tag_vsc73xx_8021q.c b/net/dsa/tag_vsc73xx_8021q.c
index af121a9aff7f..d1d7a860a76e 100644
--- a/net/dsa/tag_vsc73xx_8021q.c
+++ b/net/dsa/tag_vsc73xx_8021q.c
@@ -2,20 +2,61 @@ 
 /* Copyright (C) 2024 Pawel Dembicki <paweldembicki@gmail.com>
  */
 #include <linux/dsa/8021q.h>
+#include <linux/dsa/vsc73xx.h>
 
 #include "tag.h"
 #include "tag_8021q.h"
 
 #define VSC73XX_8021Q_NAME "vsc73xx-8021q"
 
+struct vsc73xx_8021q_tagger_private {
+	struct vsc73xx_8021q_tagger_data data; /* Must be first */
+	struct kthread_worker *xmit_worker;
+};
+
+static struct sk_buff *vsc73xx_defer_xmit(struct dsa_port *dp, struct sk_buff *skb)
+{
+	struct vsc73xx_8021q_tagger_private *priv = dp->ds->tagger_data;
+	struct vsc73xx_8021q_tagger_data *data = &priv->data;
+	void (*xmit_work_fn)(struct kthread_work *work);
+	struct vsc73xx_deferred_xmit_work *xmit_work;
+	struct kthread_worker *xmit_worker;
+
+	xmit_work_fn = data->xmit_work_fn;
+	xmit_worker = priv->xmit_worker;
+
+	if (!xmit_work_fn || !xmit_worker)
+		return NULL;
+
+	xmit_work = kzalloc(sizeof(*xmit_work), GFP_ATOMIC);
+	if (!xmit_work)
+		return NULL;
+
+	/* Calls vsc73xx_port_deferred_xmit in vitesse-vsc73xx-core.c */
+	kthread_init_work(&xmit_work->work, xmit_work_fn);
+	/* Increase refcount so the kfree_skb in dsa_slave_xmit
+	 * won't really free the packet.
+	 */
+	xmit_work->dp = dp;
+	xmit_work->skb = skb_get(skb);
+
+	kthread_queue_work(xmit_worker, &xmit_work->work);
+
+	return NULL;
+}
+
 static struct sk_buff *
 vsc73xx_xmit(struct sk_buff *skb, struct net_device *netdev)
 {
 	struct dsa_port *dp = dsa_user_to_port(netdev);
 	u16 queue_mapping = skb_get_queue_mapping(skb);
 	u16 tx_vid = dsa_tag_8021q_standalone_vid(dp);
+	struct ethhdr *hdr = eth_hdr(skb);
 	u8 pcp;
 
+	if (is_link_local_ether_addr(hdr->h_dest))
+		return vsc73xx_defer_xmit(dp, skb);
+
 	if (skb->offload_fwd_mark) {
 		unsigned int bridge_num = dsa_port_bridge_num_get(dp);
 		struct net_device *br = dsa_port_bridge_dev_get(dp);
@@ -52,11 +93,43 @@  vsc73xx_rcv(struct sk_buff *skb, struct net_device *netdev)
 	return skb;
 }
 
+static void vsc73xx_disconnect(struct dsa_switch *ds)
+{
+	struct vsc73xx_8021q_tagger_private *priv = ds->tagger_data;
+
+	kthread_destroy_worker(priv->xmit_worker);
+	kfree(priv);
+	ds->tagger_data = NULL;
+}
+
+static int vsc73xx_connect(struct dsa_switch *ds)
+{
+	struct vsc73xx_8021q_tagger_private *priv;
+	int err;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->xmit_worker = kthread_create_worker(0, "vsc73xx_xmit");
+	if (IS_ERR(priv->xmit_worker)) {
+		err = PTR_ERR(priv->xmit_worker);
+		kfree(priv);
+		return err;
+	}
+
+	ds->tagger_data = priv;
+
+	return 0;
+}
+
 static const struct dsa_device_ops vsc73xx_8021q_netdev_ops = {
 	.name			= VSC73XX_8021Q_NAME,
 	.proto			= DSA_TAG_PROTO_VSC73XX_8021Q,
 	.xmit			= vsc73xx_xmit,
 	.rcv			= vsc73xx_rcv,
+	.connect		= vsc73xx_connect,
+	.disconnect		= vsc73xx_disconnect,
 	.needed_headroom	= VLAN_HLEN,
 	.promisc_on_conduit	= true,
 };