bmips: backport b53 legacy tags support

These patches have been accepted upstream for linux 5.13.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

3 files changed, 216 insertions, 88 deletions

diff --git a/target/linux/bmips/patches-5.10/010-v5.11-net-dsa-implement-a-central-TX-reallocation-procedur.patch b/target/linux/bmips/patches-5.10/010-v5.11-net-dsa-implement-a-central-TX-reallocation-procedur.patch
new file mode 100644
index 0000000000..4171a69d1d
--- /dev/null
+++ b/target/linux/bmips/patches-5.10/010-v5.11-net-dsa-implement-a-central-TX-reallocation-procedur.patch
@@ -0,0 +1,104 @@
+From a3b0b6479700a5b0af2c631cb2ec0fb7a0d978f2 Mon Sep 17 00:00:00 2001
+From: Vladimir Oltean <vladimir.oltean@nxp.com>
+Date: Sun, 1 Nov 2020 21:16:09 +0200
+Subject: [PATCH] net: dsa: implement a central TX reallocation procedure
+
+At the moment, taggers are left with the task of ensuring that the skb
+headers are writable (which they aren't, if the frames were cloned for
+TX timestamping, for flooding by the bridge, etc), and that there is
+enough space in the skb data area for the DSA tag to be pushed.
+
+Moreover, the life of tail taggers is even harder, because they need to
+ensure that short frames have enough padding, a problem that normal
+taggers don't have.
+
+The principle of the DSA framework is that everything except for the
+most intimate hardware specifics (like in this case, the actual packing
+of the DSA tag bits) should be done inside the core, to avoid having
+code paths that are very rarely tested.
+
+So provide a TX reallocation procedure that should cover the known needs
+of DSA today.
+
+Note that this patch also gives the network stack a good hint about the
+headroom/tailroom it's going to need. Up till now it wasn't doing that.
+So the reallocation procedure should really be there only for the
+exceptional cases, and for cloned packets which need to be unshared.
+
+Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
+Tested-by: Christian Eggers <ceggers@arri.de> # For tail taggers only
+Tested-by: Kurt Kanzenbach <kurt@linutronix.de>
+Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
+Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+---
+ net/dsa/slave.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 45 insertions(+)
+
+--- a/net/dsa/slave.c
++++ b/net/dsa/slave.c
+@@ -548,6 +548,30 @@ netdev_tx_t dsa_enqueue_skb(struct sk_bu
+ }
+ EXPORT_SYMBOL_GPL(dsa_enqueue_skb);
+ 
++static int dsa_realloc_skb(struct sk_buff *skb, struct net_device *dev)
++{
++	int needed_headroom = dev->needed_headroom;
++	int needed_tailroom = dev->needed_tailroom;
++
++	/* For tail taggers, we need to pad short frames ourselves, to ensure
++	 * that the tail tag does not fail at its role of being at the end of
++	 * the packet, once the master interface pads the frame. Account for
++	 * that pad length here, and pad later.
++	 */
++	if (unlikely(needed_tailroom && skb->len < ETH_ZLEN))
++		needed_tailroom += ETH_ZLEN - skb->len;
++	/* skb_headroom() returns unsigned int... */
++	needed_headroom = max_t(int, needed_headroom - skb_headroom(skb), 0);
++	needed_tailroom = max_t(int, needed_tailroom - skb_tailroom(skb), 0);
++
++	if (likely(!needed_headroom && !needed_tailroom && !skb_cloned(skb)))
++		/* No reallocation needed, yay! */
++		return 0;
++
++	return pskb_expand_head(skb, needed_headroom, needed_tailroom,
++				GFP_ATOMIC);
++}
++
+ static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev)
+ {
+ 	struct dsa_slave_priv *p = netdev_priv(dev);
+@@ -567,6 +591,17 @@ static netdev_tx_t dsa_slave_xmit(struct
+ 	 */
+ 	dsa_skb_tx_timestamp(p, skb);
+ 
++	if (dsa_realloc_skb(skb, dev)) {
++		dev_kfree_skb_any(skb);
++		return NETDEV_TX_OK;
++	}
++
++	/* needed_tailroom should still be 'warm' in the cache line from
++	 * dsa_realloc_skb(), which has also ensured that padding is safe.
++	 */
++	if (dev->needed_tailroom)
++		eth_skb_pad(skb);
++
+ 	/* Transmit function may have to reallocate the original SKB,
+ 	 * in which case it must have freed it. Only free it here on error.
+ 	 */
+@@ -1825,6 +1860,16 @@ int dsa_slave_create(struct dsa_port *po
+ 	slave_dev->netdev_ops = &dsa_slave_netdev_ops;
+ 	if (ds->ops->port_max_mtu)
+ 		slave_dev->max_mtu = ds->ops->port_max_mtu(ds, port->index);
++	if (cpu_dp->tag_ops->tail_tag)
++		slave_dev->needed_tailroom = cpu_dp->tag_ops->overhead;
++	else
++		slave_dev->needed_headroom = cpu_dp->tag_ops->overhead;
++	/* Try to save one extra realloc later in the TX path (in the master)
++	 * by also inheriting the master's needed headroom and tailroom.
++	 * The 8021q driver also does this.
++	 */
++	slave_dev->needed_headroom += master->needed_headroom;
++	slave_dev->needed_tailroom += master->needed_tailroom;
+ 	SET_NETDEV_DEVTYPE(slave_dev, &dsa_type);
+ 
+ 	netdev_for_each_tx_queue(slave_dev, dsa_slave_set_lockdep_class_one,
diff --git a/target/linux/bmips/patches-5.10/502-net-dsa-b53-support-tags-for-legacy-switches.patch b/target/linux/bmips/patches-5.10/049-v5.13-net-dsa-tag_brcm-add-support-for-legacy-tags.patch
index b8aa8b844d..a9b689ca9c 100644
--- a/target/linux/bmips/patches-5.10/502-net-dsa-b53-support-tags-for-legacy-switches.patch
+++ b/target/linux/bmips/patches-5.10/049-v5.13-net-dsa-tag_brcm-add-support-for-legacy-tags.patch
@@ -1,59 +1,22 @@
-From 3bc3d79efdff6e29b80bf35f7a56baaa36e4d8fe Mon Sep 17 00:00:00 2001
+From 964dbf186eaa84d409c359ddf09c827a3fbe8228 Mon Sep 17 00:00:00 2001
 From: =?UTF-8?q?=C3=81lvaro=20Fern=C3=A1ndez=20Rojas?= <noltari@gmail.com>
-Date: Fri, 12 Mar 2021 12:35:39 +0100
-Subject: [PATCH] net: dsa: b53: support tags for legacy switches
+Date: Wed, 17 Mar 2021 11:29:26 +0100
+Subject: [PATCH 1/2] net: dsa: tag_brcm: add support for legacy tags
 MIME-Version: 1.0
 Content-Type: text/plain; charset=UTF-8
 Content-Transfer-Encoding: 8bit
 
+Add support for legacy Broadcom tags, which are similar to DSA_TAG_PROTO_BRCM.
+These tags are used on BCM5325, BCM5365 and BCM63xx switches.
+
 Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
 ---
- drivers/net/dsa/b53/Kconfig      |  1 +
- drivers/net/dsa/b53/b53_common.c |  6 +++
- include/net/dsa.h                |  2 +
- net/dsa/Kconfig                  |  7 +++
- net/dsa/tag_brcm.c               | 93 ++++++++++++++++++++++++++++++++
- 5 files changed, 109 insertions(+)
+ include/net/dsa.h  |   2 +
+ net/dsa/Kconfig    |   7 +++
+ net/dsa/tag_brcm.c | 107 +++++++++++++++++++++++++++++++++++++++++++--
+ 3 files changed, 113 insertions(+), 3 deletions(-)
 
---- a/drivers/net/dsa/b53/Kconfig
-+++ b/drivers/net/dsa/b53/Kconfig
-@@ -3,6 +3,7 @@ menuconfig B53
- 	tristate "Broadcom BCM53xx managed switch support"
- 	depends on NET_DSA
- 	select NET_DSA_TAG_BRCM
-+	select NET_DSA_TAG_BRCM_LEGACY
- 	select NET_DSA_TAG_BRCM_PREPEND
- 	help
- 	  This driver adds support for Broadcom managed switch chips. It supports
---- a/drivers/net/dsa/b53/b53_common.c
-+++ b/drivers/net/dsa/b53/b53_common.c
-@@ -1992,6 +1992,7 @@ static bool b53_can_enable_brcm_tags(str
- 
- 	switch (tag_protocol) {
- 	case DSA_TAG_PROTO_BRCM:
-+	case DSA_TAG_PROTO_BRCM_LEGACY:
- 	case DSA_TAG_PROTO_BRCM_PREPEND:
- 		dev_warn(ds->dev,
- 			 "Port %d is stacked to Broadcom tag switch\n", port);
-@@ -2013,12 +2014,16 @@ enum dsa_tag_protocol b53_get_tag_protoc
- 	/* Older models (5325, 5365) support a different tag format that we do
- 	 * not support in net/dsa/tag_brcm.c yet.
- 	 */
--	if (is5325(dev) || is5365(dev) ||
--	    !b53_can_enable_brcm_tags(ds, port, mprot)) {
-+	if (!b53_can_enable_brcm_tags(ds, port, mprot)) {
- 		dev->tag_protocol = DSA_TAG_PROTO_NONE;
- 		goto out;
- 	}
- 
-+	if (is5325(dev) || is5365(dev) || is63xx(dev)) {
-+		dev->tag_protocol = DSA_TAG_PROTO_BRCM_LEGACY;
-+		goto out;
-+	}
-+
- 	/* Broadcom BCM58xx chips have a flow accelerator on Port 8
- 	 * which requires us to use the prepended Broadcom tag type
- 	 */
 --- a/include/net/dsa.h
 +++ b/include/net/dsa.h
 @@ -45,10 +45,12 @@ struct phylink_link_state;
@@ -87,31 +50,37 @@ Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
  	tristate "Tag driver for Broadcom switches using prepended headers"
 --- a/net/dsa/tag_brcm.c
 +++ b/net/dsa/tag_brcm.c
-@@ -8,9 +8,23 @@
- #include <linux/etherdevice.h>
- #include <linux/list.h>
- #include <linux/slab.h>
-+#include <linux/types.h>
+@@ -11,9 +11,26 @@
  
  #include "dsa_priv.h"
  
-+struct bcm_legacy_tag {
-+	uint16_t type;
-+#define BRCM_LEG_TYPE	0x8874
-+
-+	uint32_t tag;
-+#define BRCM_LEG_TAG_PORT_ID	(0xf)
-+#define BRCM_LEG_TAG_MULTICAST	(1 << 29)
-+#define BRCM_LEG_TAG_EGRESS	(2 << 29)
-+#define BRCM_LEG_TAG_INGRESS	(3 << 29)
-+} __attribute__((packed));
-+
-+#define BRCM_LEG_TAG_LEN	sizeof(struct bcm_legacy_tag)
-+
- /* This tag length is 4 bytes, older ones were 6 bytes, we do not
-  * handle them
-  */
-@@ -197,6 +211,85 @@ DSA_TAG_DRIVER(brcm_netdev_ops);
+-/* This tag length is 4 bytes, older ones were 6 bytes, we do not
+- * handle them
+- */
++/* Legacy Broadcom tag (6 bytes) */
++#define BRCM_LEG_TAG_LEN	6
++
++/* Type fields */
++/* 1st byte in the tag */
++#define BRCM_LEG_TYPE_HI	0x88
++/* 2nd byte in the tag */
++#define BRCM_LEG_TYPE_LO	0x74
++
++/* Tag fields */
++/* 3rd byte in the tag */
++#define BRCM_LEG_UNICAST	(0 << 5)
++#define BRCM_LEG_MULTICAST	(1 << 5)
++#define BRCM_LEG_EGRESS		(2 << 5)
++#define BRCM_LEG_INGRESS	(3 << 5)
++
++/* 6th byte in the tag */
++#define BRCM_LEG_PORT_ID	(0xf)
++
++/* Newer Broadcom tag (4 bytes) */
+ #define BRCM_TAG_LEN	4
+ 
+ /* Tag is constructed and desconstructed using byte by byte access
+@@ -197,6 +214,87 @@ DSA_TAG_DRIVER(brcm_netdev_ops);
  MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_BRCM);
  #endif
  
@@ -120,10 +89,7 @@ Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
 +					 struct net_device *dev)
 +{
 +	struct dsa_port *dp = dsa_slave_to_port(dev);
-+	struct bcm_legacy_tag *brcm_tag;
-+
-+	if (skb_cow_head(skb, BRCM_LEG_TAG_LEN) < 0)
-+		return NULL;
++	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
@@ -141,29 +107,34 @@ Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
 +
 +	memmove(skb->data, skb->data + BRCM_LEG_TAG_LEN, 2 * ETH_ALEN);
 +
-+	brcm_tag = (struct bcm_legacy_tag *) (skb->data + 2 * ETH_ALEN);
++	brcm_tag = skb->data + 2 * ETH_ALEN;
 +
-+	brcm_tag->type = BRCM_LEG_TYPE;
-+	brcm_tag->tag = BRCM_LEG_TAG_EGRESS;
-+	brcm_tag->tag |= dp->index & BRCM_LEG_TAG_PORT_ID;
++	/* 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_tag[3] = 0;
++	brcm_tag[4] = 0;
++	brcm_tag[5] = dp->index & BRCM_LEG_PORT_ID;
 +
 +	return skb;
 +}
 +
-+
 +static struct sk_buff *brcm_leg_tag_rcv(struct sk_buff *skb,
 +					struct net_device *dev,
 +					struct packet_type *pt)
 +{
 +	int source_port;
-+	struct bcm_legacy_tag *brcm_tag;
++	u8 *brcm_tag;
 +
-+	if (unlikely(!pskb_may_pull(skb, BRCM_LEG_TAG_LEN)))
++	if (unlikely(!pskb_may_pull(skb, BRCM_LEG_PORT_ID)))
 +		return NULL;
 +
-+	brcm_tag = (struct bcm_legacy_tag *) (skb->data - 2);
++	brcm_tag = skb->data - 2;
 +
-+	source_port = brcm_tag->tag & BRCM_LEG_TAG_PORT_ID;
++	source_port = brcm_tag[5] & BRCM_LEG_PORT_ID;
 +
 +	skb->dev = dsa_master_find_slave(dev, 0, source_port);
 +	if (!skb->dev)
@@ -183,10 +154,10 @@ Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
 +}
 +
 +static const struct dsa_device_ops brcm_legacy_netdev_ops = {
-+	.name	= "brcm-legacy",
-+	.proto	= DSA_TAG_PROTO_BRCM_LEGACY,
-+	.xmit	= brcm_leg_tag_xmit,
-+	.rcv	= brcm_leg_tag_rcv,
++	.name = "brcm-legacy",
++	.proto = DSA_TAG_PROTO_BRCM_LEGACY,
++	.xmit = brcm_leg_tag_xmit,
++	.rcv = brcm_leg_tag_rcv,
 +	.overhead = BRCM_LEG_TAG_LEN,
 +};
 +
@@ -197,7 +168,7 @@ Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
  #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)
-@@ -229,6 +322,9 @@ static struct dsa_tag_driver *dsa_tag_dr
+@@ -229,6 +327,9 @@ static struct dsa_tag_driver *dsa_tag_dr
  #if IS_ENABLED(CONFIG_NET_DSA_TAG_BRCM)
  	&DSA_TAG_DRIVER_NAME(brcm_netdev_ops),
  #endif
diff --git a/target/linux/bmips/patches-5.10/050-v5.13-net-dsa-b53-support-legacy-tags.patch b/target/linux/bmips/patches-5.10/050-v5.13-net-dsa-b53-support-legacy-tags.patch
new file mode 100644
index 0000000000..59a7217663
--- /dev/null
+++ b/target/linux/bmips/patches-5.10/050-v5.13-net-dsa-b53-support-legacy-tags.patch
@@ -0,0 +1,53 @@
+From 46c5176c586c81306bf9e7024c13b95da775490f Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?=C3=81lvaro=20Fern=C3=A1ndez=20Rojas?= <noltari@gmail.com>
+Date: Wed, 17 Mar 2021 11:29:27 +0100
+Subject: [PATCH 2/2] net: dsa: b53: support legacy tags
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+These tags are used on BCM5325, BCM5365 and BCM63xx switches.
+
+Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
+Acked-by: Florian Fainelli <f.fainelli@gmail.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ drivers/net/dsa/b53/Kconfig      |  1 +
+ drivers/net/dsa/b53/b53_common.c | 12 +++++++-----
+ 2 files changed, 8 insertions(+), 5 deletions(-)
+
+--- a/drivers/net/dsa/b53/Kconfig
++++ b/drivers/net/dsa/b53/Kconfig
+@@ -3,6 +3,7 @@ menuconfig B53
+ 	tristate "Broadcom BCM53xx managed switch support"
+ 	depends on NET_DSA
+ 	select NET_DSA_TAG_BRCM
++	select NET_DSA_TAG_BRCM_LEGACY
+ 	select NET_DSA_TAG_BRCM_PREPEND
+ 	help
+ 	  This driver adds support for Broadcom managed switch chips. It supports
+--- a/drivers/net/dsa/b53/b53_common.c
++++ b/drivers/net/dsa/b53/b53_common.c
+@@ -2010,15 +2010,17 @@ enum dsa_tag_protocol b53_get_tag_protoc
+ {
+ 	struct b53_device *dev = ds->priv;
+ 
+-	/* Older models (5325, 5365) support a different tag format that we do
+-	 * not support in net/dsa/tag_brcm.c yet.
+-	 */
+-	if (is5325(dev) || is5365(dev) ||
+-	    !b53_can_enable_brcm_tags(ds, port, mprot)) {
++	if (!b53_can_enable_brcm_tags(ds, port, mprot)) {
+ 		dev->tag_protocol = DSA_TAG_PROTO_NONE;
+ 		goto out;
+ 	}
+ 
++	/* Older models require a different 6 byte tag */
++	if (is5325(dev) || is5365(dev) || is63xx(dev)) {
++		dev->tag_protocol = DSA_TAG_PROTO_BRCM_LEGACY;
++		goto out;
++	}
++
+ 	/* Broadcom BCM58xx chips have a flow accelerator on Port 8
+ 	 * which requires us to use the prepended Broadcom tag type
+ 	 */