[PATCH net-next v9 0/4] net: dsa: microchip: Add support for KSZ8995XA/KS8995XA

@@ -23,6 +23,7 @@ properties:
       - microchip,ksz8864  # 4-port version of KSZ8895 family switch
       - microchip,ksz8873
       - microchip,ksz8895  # 5-port version of KSZ8895 family switch
+      - microchip,ksz8995xa
       - microchip,ksz9477
       - microchip,ksz9897
       - microchip,ksz9896

@@ -17776,6 +17776,7 @@ F:	Documentation/devicetree/bindings/net/dsa/microchip,lan937x.yaml
 F:	drivers/net/dsa/microchip/*
 F:	include/linux/dsa/ksz_common.h
 F:	include/linux/platform_data/microchip-ksz.h
+F:	net/dsa/tag_ks8995.c
 F:	net/dsa/tag_ksz.c
 
 MICROCHIP LAN743X ETHERNET DRIVER

@@ -61,6 +61,7 @@ struct tc_action;
 #define DSA_TAG_PROTO_NETC_VALUE		33
 #define DSA_TAG_PROTO_KSZ8463_VALUE		34
 #define DSA_TAG_PROTO_MT7628_VALUE		35
+#define DSA_TAG_PROTO_KS8995_VALUE		36
 
 enum dsa_tag_protocol {
 	DSA_TAG_PROTO_NONE		= DSA_TAG_PROTO_NONE_VALUE,

@@ -99,6 +100,7 @@ enum dsa_tag_protocol {
 	DSA_TAG_PROTO_NETC		= DSA_TAG_PROTO_NETC_VALUE,
 	DSA_TAG_PROTO_KSZ8463		= DSA_TAG_PROTO_KSZ8463_VALUE,
 	DSA_TAG_PROTO_MT7628		= DSA_TAG_PROTO_MT7628_VALUE,
+	DSA_TAG_PROTO_KS8995		= DSA_TAG_PROTO_KS8995_VALUE,
 };
 
 struct dsa_switch;

@@ -125,6 +125,12 @@ config NET_DSA_TAG_MXL_GSW1XX
 	  Say Y or M if you want to enable support for tagging frames for
 	  MaxLinear GSW1xx switches.
 
+config NET_DSA_TAG_KS8995
+	tristate "Tag driver for Micrel KS8995 switch"
+	help
+	  Say Y if you want to enable support for tagging frames for the
+	  Micrel KS8995 switch.
+
 config NET_DSA_TAG_KSZ
 	tristate "Tag driver for Microchip 8795/937x/9477/9893 families of switches"
 	help

@@ -25,6 +25,7 @@ obj-$(CONFIG_NET_DSA_TAG_BRCM_COMMON) += tag_brcm.o
 obj-$(CONFIG_NET_DSA_TAG_DSA_COMMON) += tag_dsa.o
 obj-$(CONFIG_NET_DSA_TAG_GSWIP) += tag_gswip.o
 obj-$(CONFIG_NET_DSA_TAG_HELLCREEK) += tag_hellcreek.o
+obj-$(CONFIG_NET_DSA_TAG_KS8995) += tag_ks8995.o
 obj-$(CONFIG_NET_DSA_TAG_KSZ) += tag_ksz.o
 obj-$(CONFIG_NET_DSA_TAG_LAN9303) += tag_lan9303.o
 obj-$(CONFIG_NET_DSA_TAG_MT7628) += tag_mt7628.o

@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2026 Linus Walleij <linusw@kernel.org>
+ */
+#include <linux/etherdevice.h>
+#include <linux/log2.h>
+#include <linux/list.h>
+#include <linux/net.h>
+#include <linux/slab.h>
+
+#include "tag.h"
+
+/* The Micrel KS8995XA / Microchip KSZ8995XA Special Tag Packet ID (STPID)
+ * pushes its tag in a modified VLAN (802.1Q) tag.
+ * -----------------------------------------------------------
+ * | MAC DA | MAC SA | 2 bytes tag | 2 bytes TCI | EtherType |
+ * -----------------------------------------------------------
+ * The tag is: 0x8100 |= BIT(port), ports 0,1,2,3
+ */
+
+#define KS8995_NAME "ks8995"
+
+#define KS8995M_STPID_STD	GENMASK(15, 4)
+#define KS8995M_STPID_PORTMASK	GENMASK(3, 0)
+#define KS8995M_STPID(portmask)	htons(ETH_P_8021Q | FIELD_PREP(KS8995M_STPID_PORTMASK, portmask))
+
+static struct sk_buff *ks8995_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct vlan_ethhdr *hdr;
+	u16 portmask;
+
+	/* Prepare the special KS8995 tags */
+	portmask = dsa_xmit_port_mask(skb, dev);
+
+	/* The switch expects the special tag at offset 12. Move any hardware
+	 * accelerated VLAN tag into the payload so the conduit cannot insert
+	 * it outside the special tag.
+	 */
+	if (unlikely(skb_vlan_tag_present(skb))) {
+		skb = __vlan_hwaccel_push_inside(skb);
+		if (!skb)
+			return NULL;
+	}
+
+	/* Always add a distinct outer tag. The user port removes this field on
+	 * egress, so reusing an existing 802.1Q tag would consume that VLAN tag.
+	 */
+	skb = vlan_insert_tag(skb, KS8995M_STPID(portmask), 0);
+	/* vlan_insert_tag() drops the skb on failure */
+	if (!skb)
+		return NULL;
+	hdr = skb_vlan_eth_hdr(skb);
+	netdev_dbg(dev, "%s: inserted VLAN TAG %04x TCI %04x\n",
+		   __func__, hdr->h_vlan_proto, hdr->h_vlan_TCI);
+
+	return skb;
+}
+
+static struct sk_buff *ks8995_rcv(struct sk_buff *skb, struct net_device *dev)
+{
+	int portmask;
+	u16 etype;
+
+	/* We are expecting all received packets to have a mangled VLAN
+	 * TPID, so drop anything else. Because of the non-standard TPID,
+	 * don't even bother looking for a tag in the hwaccel area.
+	 *
+	 * We have to inspect the ethertype directly because skb->protocol
+	 * will contain garbage.
+	 */
+	etype = ntohs(*(__be16 *)dsa_etype_header_pos_rx(skb));
+	if ((etype & KS8995M_STPID_STD) != ETH_P_8021Q) {
+		netdev_dbg(dev, "%s: dropped ethertype 0x%04x\n",
+			   __func__, etype);
+		kfree_skb(skb);
+		return NULL;
+	}
+	netdev_dbg(dev, "%s: received ethertype %04x\n",
+		   __func__, etype);
+
+	/* Move the custom DSA+VLAN tag into the hwaccel area and strip
+	 * it from the skb head
+	 */
+	skb = skb_vlan_untag(skb);
+	if (!skb) {
+		/* skb_vlan_untag drops the skb on failure */
+		if (net_ratelimit())
+			netdev_err(dev, "%s: unable to untag skb\n", __func__);
+		return NULL;
+	}
+
+	portmask = FIELD_GET(KS8995M_STPID_PORTMASK, etype);
+	netdev_dbg(dev, "%s: etype %04x portmask %04x (%d)\n",
+		   __func__, etype, portmask, ilog2(portmask));
+	skb->dev = dsa_conduit_find_user(dev, 0, ilog2(portmask));
+	if (!skb->dev) {
+		kfree_skb(skb);
+		return NULL;
+	}
+
+	/* skb_vlan_untag() moved the special tag's TCI into the hardware-
+	 * accelerated VLAN metadata. The switch preserves the TCI of tagged
+	 * frames, but inserts the ingress port's default tag for untagged frames.
+	 * Since the driver programs the default tag to 0, a zero TCI identifies
+	 * an originally untagged frame. Preserve every non-zero TCI as an
+	 * 802.1Q tag, including VID 0 frames with PCP or DEI set.
+	 */
+	if (!skb->vlan_tci) {
+		netdev_dbg(dev, "%s: clear VLAN tag from frame\n", __func__);
+		__vlan_hwaccel_clear_tag(skb);
+	} else {
+		skb->vlan_proto = htons(ETH_P_8021Q);
+		netdev_dbg(dev, "%s: vlan_tci = 0x%04x VLAN frame\n",
+			   __func__, skb->vlan_tci);
+	}
+
+	dsa_default_offload_fwd_mark(skb);
+
+	return skb;
+}
+
+static const struct dsa_device_ops ks8995_netdev_ops = {
+	.name = KS8995_NAME,
+	.proto	= DSA_TAG_PROTO_KS8995,
+	.xmit = ks8995_xmit,
+	.rcv = ks8995_rcv,
+	.needed_headroom = VLAN_HLEN,
+};
+
+MODULE_DESCRIPTION("DSA tag driver for Micrel KS8995 family of switches");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_DSA_TAG_DRIVER(DSA_TAG_PROTO_KS8995, KS8995_NAME);
+
+module_dsa_tag_driver(ks8995_netdev_ops);

@@ -110,6 +110,7 @@ config NET_DSA_RZN1_A5PSW
 config NET_DSA_KS8995
 	tristate "Micrel KS8995 family 5-ports 10/100 Ethernet switches"
 	depends on SPI
+	depends on NET_DSA_MICROCHIP_KSZ_SPI = n
 	select NET_DSA_TAG_NONE
 	help
 	  This driver supports the Micrel KS8995 family of 10/100 Mbit ethernet

@@ -2,6 +2,7 @@
 menuconfig NET_DSA_MICROCHIP_KSZ_COMMON
 	tristate "Microchip KSZ8XXX/KSZ9XXX/LAN937X series switch support"
 	depends on NET_DSA
+	select NET_DSA_TAG_KS8995
 	select NET_DSA_TAG_KSZ
 	select NET_DSA_TAG_NONE
 	select NET_IEEE8021Q_HELPERS

@@ -3,6 +3,7 @@
  * Microchip KSZ8XXX series switch driver
  *
  * It supports the following switches:
+ * - KSZ8995XA (the oldest ancestor)
  * - KSZ8463
  * - KSZ8863, KSZ8873 aka KSZ88X3
  * - KSZ8895, KSZ8864 aka KSZ8895 family

@@ -253,7 +254,17 @@ static int ksz8463_reset_switch(struct ksz_device *dev)
 
 static int ksz8_reset_switch(struct ksz_device *dev)
 {
-	if (ksz_is_ksz88x3(dev)) {
+	if (ksz_is_ksz8995xa(dev)) {
+		unsigned int port;
+
+		/* The KSZ8995XA switch itself cannot be reset by software, but
+		 * often boot loaders have fun with ports, so reset them. This
+		 * reset bit is self-clearing.
+		 */
+		for (port = 0; port < dev->info->port_cnt; port++)
+			ksz_port_cfg(dev, port, REG_PORT_STATUS_3,
+				     PORT_PHY_SOFT_RESET, true);
+	} else if (ksz_is_ksz88x3(dev)) {
 		/* reset switch */
 		ksz_cfg(dev, KSZ8863_REG_SW_RESET,
 			KSZ8863_GLOBAL_SOFTWARE_RESET | KSZ8863_PCS_RESET, true);

@@ -269,6 +280,31 @@ static int ksz8_reset_switch(struct ksz_device *dev)
 	return 0;
 }
 
+static int ksz8995xa_change_mtu(struct dsa_switch *ds, int port, int mtu)
+{
+	struct ksz_device *dev = ds->priv;
+	int frame_size;
+	u8 ctrl2 = 0;
+
+	if (!dsa_is_cpu_port(dev->ds, port))
+		return 0;
+
+	frame_size = mtu + VLAN_ETH_HLEN + ETH_FCS_LEN;
+
+	/* The legal packet size bit polarity documented in the KSZ8995XA
+	 * manual appears to be wrong. Practical tests show that the same
+	 * semantics as the other switches are correct; using the documented
+	 * polarity makes the switch hang on big packets.
+	 */
+	if (frame_size <= KSZ8995XA_LEGAL_PACKET_SIZE)
+		ctrl2 |= KSZ8863_LEGAL_PACKET_ENABLE;
+	else if (frame_size > KSZ8863_NORMAL_PACKET_SIZE)
+		ctrl2 |= KSZ8863_HUGE_PACKET_ENABLE;
+
+	return ksz_rmw8(dev, REG_SW_CTRL_2, KSZ8863_LEGAL_PACKET_ENABLE |
+			KSZ8863_HUGE_PACKET_ENABLE, ctrl2);
+}
+
 static int ksz88xx_change_mtu(struct dsa_switch *ds, int port, int mtu)
 {
 	struct ksz_device *dev = ds->priv;

@@ -325,8 +361,8 @@ static int ksz88xx_max_mtu(struct dsa_switch *ds, int port)
 
 static int ksz8_port_queue_split(struct ksz_device *dev, int port, int queues)
 {
-	u8 mask_4q, mask_2q;
-	u8 reg_4q, reg_2q;
+	u8 mask_4q = 0, mask_2q;
+	u8 reg_4q = 0, reg_2q;
 	u8 data_4q = 0;
 	u8 data_2q = 0;
 	int ret;

@@ -352,6 +388,10 @@ static int ksz8_port_queue_split(struct ksz_device *dev, int port, int queues)
 		mask_2q = KSZ8873_PORT_2QUEUE_SPLIT_EN;
 		reg_4q = P1CR1;
 		reg_2q = P1CR1 + 1;
+	} else if (ksz_is_ksz8995xa(dev)) {
+		/* This switch has no 4way split support */
+		mask_2q = KSZ8795_PORT_2QUEUE_SPLIT_EN;
+		reg_2q = REG_PORT_CTRL_0;
 	} else {
 		mask_4q = KSZ8795_PORT_4QUEUE_SPLIT_EN;
 		mask_2q = KSZ8795_PORT_2QUEUE_SPLIT_EN;

@@ -373,9 +413,11 @@ static int ksz8_port_queue_split(struct ksz_device *dev, int port, int queues)
 	else if (queues == 2)
 		data_2q = mask_2q;
 
-	ret = ksz_prmw8(dev, port, reg_4q, mask_4q, data_4q);
-	if (ret)
-		return ret;
+	if (mask_4q) {
+		ret = ksz_prmw8(dev, port, reg_4q, mask_4q, data_4q);
+		if (ret)
+			return ret;
+	}
 
 	return ksz_prmw8(dev, port, reg_2q, mask_2q, data_2q);
 }

@@ -970,6 +1012,10 @@ static int ksz8_r_phy_ctrl(struct ksz_device *dev, int port, u16 *val)
 	if (reg_val & PORT_MDIX_STATUS)
 		*val |= KSZ886X_CTRL_MDIX_STAT;
 
+	/* KSZ8995XA has no fancy features in register 0xA */
+	if (ksz_is_ksz8995xa(dev))
+		return 0;
+
 	ret = ksz_pread8(dev, port, REG_PORT_LINK_MD_CTRL, &reg_val);
 	if (ret < 0)
 		return ret;

@@ -1068,8 +1114,10 @@ static int ksz8_r_phy_bmcr(struct ksz_device *dev, u16 port, u16 *val)
 	if (ctrl & PORT_FORCE_FULL_DUPLEX)
 		*val |= BMCR_FULLDPLX;
 
-	if (speed & PORT_HP_MDIX)
-		*val |= KSZ886X_BMCR_HP_MDIX;
+	if (!ksz_is_ksz8995xa(dev)) {
+		if (speed & PORT_HP_MDIX)
+			*val |= KSZ886X_BMCR_HP_MDIX;
+	}
 
 	if (restart & PORT_FORCE_MDIX)
 		*val |= KSZ886X_BMCR_FORCE_MDI;

@@ -1164,6 +1212,9 @@ static int ksz8_r_phy(struct ksz_device *dev, u16 phy, u16 reg, u16 *val)
 			data |= LPA_LPACK;
 		break;
 	case PHY_REG_LINK_MD:
+		if (ksz_is_ksz8995xa(dev))
+			return -EOPNOTSUPP;
+
 		ret = ksz_pread8(dev, p, REG_PORT_LINK_MD_CTRL, &val1);
 		if (ret)
 			return ret;

@@ -1307,13 +1358,15 @@ static int ksz8_w_phy_bmcr(struct ksz_device *dev, u16 port, u16 val)
 	if (val & BMCR_RESET)
 		return 0;
 
-	speed = 0;
-	if (val & KSZ886X_BMCR_HP_MDIX)
-		speed |= PORT_HP_MDIX;
+	if (!ksz_is_ksz8995xa(dev)) {
+		speed = 0;
+		if (val & KSZ886X_BMCR_HP_MDIX)
+			speed |= PORT_HP_MDIX;
 
-	ret = ksz_prmw8(dev, port, regs[P_SPEED_STATUS], PORT_HP_MDIX, speed);
-	if (ret)
-		return ret;
+		ret = ksz_prmw8(dev, port, regs[P_SPEED_STATUS], PORT_HP_MDIX, speed);
+		if (ret)
+			return ret;
+	}
 
 	ctrl = 0;
 	if (ksz_is_ksz88x3(dev)) {

@@ -1423,11 +1476,17 @@ static int ksz8_w_phy(struct ksz_device *dev, u16 phy, u16 reg, u16 val)
 		}
 		break;
 	case PHY_REG_LINK_MD:
+		if (ksz_is_ksz8995xa(dev))
+			return -EOPNOTSUPP;
+
 		if (val & PHY_START_CABLE_DIAG)
 			ksz_port_cfg(dev, p, REG_PORT_LINK_MD_CTRL, PORT_START_CABLE_DIAG, true);
 		break;
 
 	case PHY_REG_PHY_CTRL:
+		if (ksz_is_ksz8995xa(dev))
+			return -EOPNOTSUPP;
+
 		ret = ksz8_w_phy_ctrl(dev, p, val);
 		if (ret)
 			return ret;

@@ -1672,7 +1731,7 @@ static int ksz8_port_vlan_filtering(struct dsa_switch *ds, int port, bool flag,
 {
 	struct ksz_device *dev = ds->priv;
 
-	if (ksz_is_ksz88x3(dev))
+	if (ksz_is_ksz88x3(dev) || ksz_is_ksz8995xa(dev))
 		return -ENOTSUPP;
 
 	/* Discard packets with VID not enabled on the switch */

@@ -2043,12 +2102,14 @@ static void ksz8_port_setup(struct ksz_device *dev, int port, bool cpu_port)
 
 	ksz8_port_queue_split(dev, port, dev->info->num_tx_queues);
 
-	/* replace priority */
-	offset = P_802_1P_CTRL;
-	if (ksz_is_ksz8463(dev))
-		offset = P1CR2;
-	ksz_port_cfg(dev, port, offset,
-		     masks[PORT_802_1P_REMAPPING], false);
+	if (!ksz_is_ksz8995xa(dev)) {
+		/* replace priority */
+		offset = P_802_1P_CTRL;
+		if (ksz_is_ksz8463(dev))
+			offset = P1CR2;
+		ksz_port_cfg(dev, port, offset,
+			     masks[PORT_802_1P_REMAPPING], false);
+	}
 
 	if (cpu_port)
 		member = dsa_user_ports(ds);

@@ -2057,6 +2118,21 @@ static void ksz8_port_setup(struct ksz_device *dev, int port, bool cpu_port)
 
 	ksz8_cfg_port_member(dev, port, member);
 
+	if (ksz_is_ksz8995xa(dev)) {
+		/* Use VID 0 to identify untagged frames in the special tag */
+		ksz_pwrite16(dev, port, REG_PORT_CTRL_VID, 0);
+
+		/* The KSZ8995XA has a special tag format in the front of the frame
+		 * that need to be inserted by the CPU and then removed by each
+		 * port. PORT_REMOVE_TAG simply means "remove tags coming from the
+		 * CPU port" it does not affect ingress packets.
+		 */
+		if (cpu_port)
+			ksz_port_cfg(dev, port, REG_PORT_CTRL_0, PORT_INSERT_TAG, true);
+		else
+			ksz_port_cfg(dev, port, REG_PORT_CTRL_0, PORT_REMOVE_TAG, true);
+	}
+
 	/* Disable all WoL options by default. Otherwise
 	 * ksz_switch_macaddr_get/put logic will not work properly.
 	 * CPU port 4 has no WoL functionality.

@@ -2073,6 +2149,7 @@ static int ksz8_dsa_port_setup(struct dsa_switch *ds, int port)
 		return 0;
 
 	ksz8_port_setup(dev, port, false);
+
 	return ksz_dcb_init_port(dev, port);
 }
 

@@ -2147,7 +2224,9 @@ static void ksz8_config_cpu_port(struct dsa_switch *ds)
 	masks = dev->info->masks;
 	regs = dev->info->regs;
 
-	ksz_cfg(dev, regs[S_TAIL_TAG_CTRL], masks[SW_TAIL_TAG_ENABLE], true);
+	/* KSZ8995XA uses a tag in the header instead of the tail */
+	if (!ksz_is_ksz8995xa(dev))
+		ksz_cfg(dev, regs[S_TAIL_TAG_CTRL], masks[SW_TAIL_TAG_ENABLE], true);
 
 	ksz8_port_setup(dev, dev->cpu_port, true);
 

@@ -2323,6 +2402,10 @@ static int ksz8_enable_stp_addr(struct ksz_device *dev)
 {
 	struct alu_struct alu;
 
+	/* KSZ8995XA lacks STP */
+	if (ksz_is_ksz8995xa(dev))
+		return 0;
+
 	/* Setup STP address for STP operation. */
 	memset(&alu, 0, sizeof(alu));
 	ether_addr_copy(alu.mac, eth_stp_addr);

@@ -2650,13 +2733,17 @@ static int ksz8_setup(struct dsa_switch *ds)
 	struct ksz_port *p;
 	const u16 *regs;
 	int i, ret;
+	u8 val;
 
 	regs = dev->info->regs;
 
-	dev->vlan_cache = devm_kcalloc(dev->dev, sizeof(struct vlan_table),
-				       dev->info->num_vlans, GFP_KERNEL);
-	if (!dev->vlan_cache)
-		return -ENOMEM;
+	/* KSZ8995XA has no SW controlled VLAN handling */
+	if (!ksz_is_ksz8995xa(dev)) {
+		dev->vlan_cache = devm_kcalloc(dev->dev, sizeof(struct vlan_table),
+					       dev->info->num_vlans, GFP_KERNEL);
+		if (!dev->vlan_cache)
+			return -ENOMEM;
+	}
 
 	ret = ksz8_reset_switch(dev);
 	if (ret) {

@@ -2711,9 +2798,10 @@ static int ksz8_setup(struct dsa_switch *ds)
 	 * Make sure unicast VLAN boundary is set as default and
 	 * enable no excessive collision drop.
 	 */
-	ret = ksz_rmw8(dev, REG_SW_CTRL_2,
-		       UNICAST_VLAN_BOUNDARY | NO_EXC_COLLISION_DROP,
-		       UNICAST_VLAN_BOUNDARY | NO_EXC_COLLISION_DROP);
+	val = NO_EXC_COLLISION_DROP;
+	if (!ksz_is_ksz8995xa(dev))
+		val |= UNICAST_VLAN_BOUNDARY;
+	ret = ksz_rmw8(dev, REG_SW_CTRL_2, val, val);
 	if (ret)
 		return ret;
 

@@ -2721,11 +2809,15 @@ static int ksz8_setup(struct dsa_switch *ds)
 
 	ksz_cfg(dev, S_MIRROR_CTRL, SW_MIRROR_RX_TX, false);
 
-	if (!ksz_is_ksz88x3(dev))
+	if (ksz_is_ksz8995xa(dev))
+		ksz_cfg(dev, REG_SW_CTRL_9, SW_SPECIAL_TAG, true);
+	else if (!ksz_is_ksz88x3(dev))
 		ksz_cfg(dev, REG_SW_CTRL_19, SW_INS_TAG_ENABLE, true);
 
-	for (i = 0; i < (dev->info->num_vlans / 4); i++)
-		ksz8_r_vlan_entries(dev, i);
+	if (!ksz_is_ksz8995xa(dev)) {
+		for (i = 0; i < (dev->info->num_vlans / 4); i++)
+			ksz8_r_vlan_entries(dev, i);
+	}
 
 	/* Make sure PME (WoL) is not enabled. If requested, it will
 	 * be enabled by ksz_wol_pre_shutdown(). Otherwise, some PMICs

@@ -2976,6 +3068,13 @@ static int ksz8_switch_init(struct ksz_device *dev)
 	return 0;
 }
 
+static enum dsa_tag_protocol ksz8995xa_get_tag_protocol(struct dsa_switch *ds,
+							int port,
+							enum dsa_tag_protocol mp)
+{
+	return DSA_TAG_PROTO_KS8995;
+}
+
 static enum dsa_tag_protocol ksz8463_get_tag_protocol(struct dsa_switch *ds,
 						      int port,
 						      enum dsa_tag_protocol mp)

@@ -3072,6 +3171,16 @@ const struct phylink_mac_ops ksz8_phylink_mac_ops = {
 	.mac_enable_tx_lpi = ksz_phylink_mac_enable_tx_lpi,
 };
 
+/*
+ * The KS(Z)8995XA has no indirect access, meaning no MIB counters,
+ * no FDB access, and no VLAN handling.
+ */
+const struct ksz_dev_ops ksz8995xa_dev_ops = {
+	.get_port_addr = ksz8_get_port_addr,
+	.cfg_port_member = ksz8_cfg_port_member,
+	.init = ksz8_switch_init,
+};
+
 const struct ksz_dev_ops ksz8463_dev_ops = {
 	.get_port_addr = ksz8463_get_port_addr,
 	.cfg_port_member = ksz8_cfg_port_member,

@@ -3111,6 +3220,38 @@ const struct ksz_dev_ops ksz88xx_dev_ops = {
 	.pme_pwrite8 = ksz8_pme_pwrite8,
 };
 
+/*
+ * Restricted operations for KSZ8995XA, so many things are not supported
+ * by this old switch that we need diet DSA operations.
+ */
+const struct dsa_switch_ops ksz8995xa_switch_ops = {
+	.get_tag_protocol	= ksz8995xa_get_tag_protocol,
+	.setup			= ksz8_setup,
+	.teardown		= ksz_teardown,
+	.phy_read		= ksz8_phy_read16,
+	.phy_write		= ksz8_phy_write16,
+	.phylink_get_caps	= ksz8_phylink_get_caps,
+	.port_setup		= ksz8_dsa_port_setup,
+	.port_bridge_join	= ksz_port_bridge_join,
+	.port_bridge_leave	= ksz_port_bridge_leave,
+	.port_set_mac_address	= ksz_port_set_mac_address,
+	.port_stp_state_set	= ksz_port_stp_state_set,
+	.port_pre_bridge_flags	= ksz_port_pre_bridge_flags,
+	.port_bridge_flags	= ksz_port_bridge_flags,
+	.port_fast_age		= ksz8_flush_dyn_mac_table,
+	.port_mirror_add	= ksz8_port_mirror_add,
+	.port_mirror_del	= ksz8_port_mirror_del,
+	.port_change_mtu	= ksz8995xa_change_mtu,
+	.port_max_mtu		= ksz88xx_max_mtu,
+	.port_get_default_prio	= ksz_port_get_default_prio,
+	.port_set_default_prio	= ksz_port_set_default_prio,
+	.port_get_dscp_prio	= ksz_port_get_dscp_prio,
+	.port_add_dscp_prio	= ksz_port_add_dscp_prio,
+	.port_del_dscp_prio	= ksz_port_del_dscp_prio,
+	.port_get_apptrust	= ksz_port_get_apptrust,
+	.port_set_apptrust	= ksz_port_set_apptrust,
+};
+
 const struct dsa_switch_ops ksz8463_switch_ops = {
 	.get_tag_protocol	= ksz8463_get_tag_protocol,
 	.connect_tag_protocol   = ksz8463_connect_tag_protocol,

@@ -12,11 +12,13 @@
 #include <net/dsa.h>
 #include "ksz_common.h"
 
+extern const struct ksz_dev_ops ksz8995xa_dev_ops;
 extern const struct ksz_dev_ops ksz8463_dev_ops;
 extern const struct ksz_dev_ops ksz87xx_dev_ops;
 extern const struct ksz_dev_ops ksz88xx_dev_ops;
 extern const struct phylink_mac_ops ksz88x3_phylink_mac_ops;
 extern const struct phylink_mac_ops ksz8_phylink_mac_ops;
+extern const struct dsa_switch_ops ksz8995xa_switch_ops;
 extern const struct dsa_switch_ops ksz8463_switch_ops;
 extern const struct dsa_switch_ops ksz87xx_switch_ops;
 extern const struct dsa_switch_ops ksz88xx_switch_ops;

@@ -30,6 +30,11 @@
 #define KSZ88X3_REG_FVID_AND_HOST_MODE  0xC6
 #define KSZ88X3_PORT3_RMII_CLK_INTERNAL BIT(3)
 
+#define REG_SW_ID_0			0x00
+#define REG_SW_ID_1			0x01
+
+#define SW_START_SWITCH			BIT(0)
+
 #define REG_SW_CTRL_0			0x02
 
 #define SW_NEW_BACKOFF			BIT(7)

@@ -95,6 +100,8 @@
 #define SW_LED_LINK_ACT_DUPLEX		2
 #define SW_LED_LINK_DUPLEX		3
 
+#define SW_SPECIAL_TAG			BIT(0) /* KSZ8995XA only */
+
 #define REG_SW_CTRL_10			0x0C
 
 #define SW_PASS_PAUSE			BIT(0)

@@ -446,6 +446,20 @@ static const u8 ksz8895_shifts[] = {
 	[DYNAMIC_MAC_SRC_PORT]		= 24,
 };
 
+static const u16 ksz8995xa_regs[] = {
+	[REG_SW_MAC_ADDR]		= 0x68,
+	[P_FORCE_CTRL]			= 0x0C,
+	[P_LINK_STATUS]			= 0x0E,
+	[P_LOCAL_CTRL]			= 0x0C,
+	[P_NEG_RESTART_CTRL]		= 0x0D,
+	[P_REMOTE_STATUS]		= 0x0E,
+	[P_SPEED_STATUS]		= 0x09,
+	[P_STP_CTRL]			= 0x02,
+	[S_START_CTRL]			= 0x01,
+	[S_BROADCAST_CTRL]		= 0x06,
+	[S_MULTICAST_CTRL]		= 0x04,
+};
+
 static const u16 ksz9477_regs[] = {
 	[REG_SW_MAC_ADDR]		= 0x0302,
 	[P_STP_CTRL]			= 0x0B04,

@@ -1377,6 +1391,21 @@ const struct ksz_chip_data ksz_switch_chips[] = {
 		.internal_phy = {true, true, true, true, false},
 	},
 
+	[KSZ8995XA] = {
+		.chip_id = KSZ8995XA_CHIP_ID, /* Also known as KS8995XA */
+		.dev_name = "KSZ8995XA",
+		.cpu_ports = 0x10,	/* can be configured as cpu port */
+		.port_cnt = 5,		/* total cpu and user ports */
+		.num_tx_queues = 2,	/* low/hi priority queues, no more */
+		.num_ipms = 2,
+		.ops = &ksz8995xa_dev_ops,
+		.switch_ops = &ksz8995xa_switch_ops,
+		.phylink_mac_ops = &ksz88x3_phylink_mac_ops,
+		.regs = ksz8995xa_regs,
+		.supports_mii = {true, true, true, true, true},
+		.internal_phy = {true, true, true, true, false},
+	},
+
 	[KSZ9477] = {
 		.chip_id = KSZ9477_CHIP_ID,
 		.dev_name = "KSZ9477",

@@ -2649,6 +2678,10 @@ void ksz_init_mib_timer(struct ksz_device *dev)
 {
 	int i;
 
+	/* KSZ8995XA lacks MiB features */
+	if (ksz_is_ksz8995xa(dev))
+		return;
+
 	INIT_DELAYED_WORK(&dev->mib_read, ksz_mib_read_work);
 
 	for (i = 0; i < dev->info->port_cnt; i++) {

@@ -2944,11 +2977,15 @@ static int ksz_switch_detect(struct ksz_device *dev)
 			return -ENODEV;
 		break;
 	case KSZ8895_FAMILY_ID:
-		if (id2 == KSZ8895_CHIP_ID_95 ||
-		    id2 == KSZ8895_CHIP_ID_95R)
+		if (id2 == KSZ8895_CHIP_ID_95XA) {
+			dev->chip_id = KSZ8995XA_CHIP_ID;
+			break;
+		} else if (id2 == KSZ8895_CHIP_ID_95 ||
+			   id2 == KSZ8895_CHIP_ID_95R) {
 			dev->chip_id = KSZ8895_CHIP_ID;
-		else
+		} else {
 			return -ENODEV;
+		}
 		ret = ksz_read8(dev, REG_KSZ8864_CHIP_ID, &id4);
 		if (ret)
 			return ret;

@@ -4029,11 +4066,13 @@ int ksz_switch_register(struct ksz_device *dev)
 	if (ret)
 		return ret;
 
-	/* Read MIB counters every 30 seconds to avoid overflow. */
-	dev->mib_read_interval = msecs_to_jiffies(5000);
+	if (!ksz_is_ksz8995xa(dev)) {
+		/* Read MIB counters every 30 seconds to avoid overflow. */
+		dev->mib_read_interval = msecs_to_jiffies(5000);
 
-	/* Start the MIB timer. */
-	schedule_delayed_work(&dev->mib_read, 0);
+		/* Start the MIB timer. */
+		schedule_delayed_work(&dev->mib_read, 0);
+	}
 
 	return ret;
 }

@@ -281,6 +281,7 @@ enum ksz_model {
 	KSZ88X3,
 	KSZ8864,
 	KSZ8895,
+	KSZ8995XA,
 	KSZ9477,
 	KSZ9896,
 	KSZ9897,

@@ -789,7 +790,13 @@ static inline bool ksz_is_ksz88x3(struct ksz_device *dev)
 static inline bool ksz_is_8895_family(struct ksz_device *dev)
 {
 	return dev->chip_id == KSZ8895_CHIP_ID ||
-	       dev->chip_id == KSZ8864_CHIP_ID;
+	       dev->chip_id == KSZ8864_CHIP_ID ||
+	       dev->chip_id == KSZ8995XA_CHIP_ID;
+}
+
+static inline bool ksz_is_ksz8995xa(struct ksz_device *dev)
+{
+	return dev->chip_id == KSZ8995XA_CHIP_ID;
 }
 
 static inline bool is_ksz8(struct ksz_device *dev)

@@ -860,6 +867,7 @@ static inline bool ksz_is_sgmii_port(struct ksz_device *dev, int port)
 #define KSZ87_CHIP_ID_94		0x6
 #define KSZ87_CHIP_ID_95		0x9
 #define KSZ88_CHIP_ID_63		0x3
+#define KSZ8895_CHIP_ID_95XA		0x0
 #define KSZ8895_CHIP_ID_95		0x4
 #define KSZ8895_CHIP_ID_95R		0x6
 

@@ -923,6 +931,7 @@ static inline bool ksz_is_sgmii_port(struct ksz_device *dev, int port)
 #define KSZ8863_HUGE_PACKET_SIZE	1916
 #define KSZ8863_NORMAL_PACKET_SIZE	1536
 #define KSZ8_LEGAL_PACKET_SIZE		1518
+#define KSZ8995XA_LEGAL_PACKET_SIZE	1522
 #define KSZ9477_MAX_FRAME_SIZE		9000
 
 #define KSZ8873_REG_GLOBAL_CTRL_12	0x0e

@@ -20,10 +20,12 @@
 #define KSZ8_PORT_DIFFSERV_ENABLE		BIT(6)
 #define KSZ8_PORT_802_1P_ENABLE			BIT(5)
 #define KSZ8_PORT_BASED_PRIO_M			GENMASK(4, 3)
+#define KSZ8995XA_PORT_BASED_PRIO		BIT(4)
 
 #define KSZ8463_REG_TOS_DSCP_CTRL		0x16
 #define KSZ88X3_REG_TOS_DSCP_CTRL		0x60
 #define KSZ8765_REG_TOS_DSCP_CTRL		0x90
+#define KSZ8995XA_REG_TOS_DSCP_CTRL_7		0x67
 
 #define KSZ9477_REG_SW_MAC_TOS_CTRL		0x033e
 #define KSZ9477_SW_TOS_DSCP_REMAP		BIT(0)

@@ -98,8 +100,11 @@ static void ksz_get_default_port_prio_reg(struct ksz_device *dev, int *reg,
 {
 	if (is_ksz8(dev)) {
 		*reg = KSZ8_REG_PORT_1_CTRL_0;
-		*mask = KSZ8_PORT_BASED_PRIO_M;
-		*shift = __bf_shf(KSZ8_PORT_BASED_PRIO_M);
+		if (ksz_is_ksz8995xa(dev))
+			*mask = KSZ8995XA_PORT_BASED_PRIO;
+		else
+			*mask = KSZ8_PORT_BASED_PRIO_M;
+		*shift = __bf_shf(*mask);
 		if (ksz_is_ksz8463(dev))
 			*reg = KSZ8463_REG_PORT_1_CTRL_0;
 	} else {

@@ -112,31 +117,45 @@ static void ksz_get_default_port_prio_reg(struct ksz_device *dev, int *reg,
 /**
  * ksz_get_dscp_prio_reg - Retrieves the DSCP-to-priority-mapping register
  * @dev: Pointer to the KSZ switch device structure
+ * @dscp: DSCP value for which to retrieve the register
  * @reg: Pointer to the register address to be set
- * @per_reg: Pointer to the number of DSCP values per register
  * @mask: Pointer to the mask to be set
+ * @shift: Pointer to the bit shift to be set
  *
- * This function retrieves the DSCP to priority mapping register, the number of
- * DSCP values per register, and the mask to be set.
+ * This function retrieves the register, mask and shift for a DSCP to priority
+ * mapping entry.
  */
-static void ksz_get_dscp_prio_reg(struct ksz_device *dev, int *reg,
-				  int *per_reg, u8 *mask)
+static void ksz_get_dscp_prio_reg(struct ksz_device *dev, u8 dscp, int *reg,
+				  u8 *mask, int *shift)
 {
+	int per_reg;
+
+	if (ksz_is_ksz8995xa(dev)) {
+		/* KSZ8995XA stores DSCP groups in descending register order. */
+		*reg = KSZ8995XA_REG_TOS_DSCP_CTRL_7 - dscp / 8;
+		*mask = BIT(0);
+		*shift = dscp % 8;
+		return;
+	}
+
 	if (ksz_is_ksz87xx(dev) || ksz_is_8895_family(dev)) {
 		*reg = KSZ8765_REG_TOS_DSCP_CTRL;
-		*per_reg = 4;
+		per_reg = 4;
 		*mask = GENMASK(1, 0);
 	} else if (ksz_is_ksz88x3(dev) || ksz_is_ksz8463(dev)) {
 		*reg = KSZ88X3_REG_TOS_DSCP_CTRL;
-		*per_reg = 4;
+		per_reg = 4;
 		*mask = GENMASK(1, 0);
 		if (ksz_is_ksz8463(dev))
 			*reg = KSZ8463_REG_TOS_DSCP_CTRL;
 	} else {
 		*reg = KSZ9477_REG_DIFFSERV_PRIO_MAP;
-		*per_reg = 2;
+		per_reg = 2;
 		*mask = GENMASK(2, 0);
 	}
+
+	*reg += dscp / per_reg;
+	*shift = (dscp % per_reg) * (8 / per_reg);
 }
 
 /**

@@ -236,10 +255,10 @@ int ksz_port_set_default_prio(struct dsa_switch *ds, int port, u8 prio)
 int ksz_port_get_dscp_prio(struct dsa_switch *ds, int port, u8 dscp)
 {
 	struct ksz_device *dev = ds->priv;
-	int reg, per_reg, ret, shift;
+	int reg, ret, shift;
 	u8 data, mask;
 
-	ksz_get_dscp_prio_reg(dev, &reg, &per_reg, &mask);
+	ksz_get_dscp_prio_reg(dev, dscp, &reg, &mask, &shift);
 
 	/* If DSCP remapping is disabled, DSCP bits 3-5 are used as Internal
 	 * Priority Map (IPM)

@@ -260,13 +279,10 @@ int ksz_port_get_dscp_prio(struct dsa_switch *ds, int port, u8 dscp)
 	/* In case DSCP remapping is enabled, we need to write the DSCP to
 	 * priority mapping table.
 	 */
-	reg += dscp / per_reg;
 	ret = ksz_read8(dev, reg, &data);
 	if (ret)
 		return ret;
 
-	shift = (dscp % per_reg) * (8 / per_reg);
-
 	return (data >> shift) & mask;
 }
 

@@ -283,15 +299,12 @@ int ksz_port_get_dscp_prio(struct dsa_switch *ds, int port, u8 dscp)
  */
 static int ksz_set_global_dscp_entry(struct ksz_device *dev, u8 dscp, u8 ipm)
 {
-	int reg, per_reg, shift;
+	int reg, shift;
 	u8 mask;
 
-	ksz_get_dscp_prio_reg(dev, &reg, &per_reg, &mask);
-
-	shift = (dscp % per_reg) * (8 / per_reg);
+	ksz_get_dscp_prio_reg(dev, dscp, &reg, &mask, &shift);
 
-	return ksz_rmw8(dev, reg + (dscp / per_reg), mask << shift,
-			ipm << shift);
+	return ksz_rmw8(dev, reg, mask << shift, ipm << shift);
 }
 
 /**

@@ -161,7 +161,8 @@ static int ksz_spi_probe(struct spi_device *spi)
 		 chip->chip_id == KSZ8794_CHIP_ID ||
 		 chip->chip_id == KSZ8765_CHIP_ID)
 		regmap_config = ksz8795_regmap_config;
-	else if (chip->chip_id == KSZ8895_CHIP_ID ||
+	else if (chip->chip_id == KSZ8995XA_CHIP_ID ||
+		 chip->chip_id == KSZ8895_CHIP_ID ||
 		 chip->chip_id == KSZ8864_CHIP_ID)
 		regmap_config = ksz8863_regmap_config;
 	else

@@ -185,7 +186,10 @@ static int ksz_spi_probe(struct spi_device *spi)
 		dev->pdata = spi->dev.platform_data;
 
 	/* setup spi */
-	spi->mode = SPI_MODE_3;
+	if (chip->chip_id == KSZ8995XA_CHIP_ID)
+		spi->mode = SPI_MODE_0;
+	else
+		spi->mode = SPI_MODE_3;
 	ret = spi_setup(spi);
 	if (ret)
 		return ret;

@@ -224,6 +228,25 @@ static void ksz_spi_shutdown(struct spi_device *spi)
 }
 
 static const struct of_device_id ksz_dt_ids[] = {
+	/*
+	 * Legacy Micrel bindings. In 2015 Microchip acquired
+	 * Micrel which is the originator of the KSZ series, and
+	 * devices branded for Micrel already existed, as well as
+	 * some device tree bindings. These two products are identical
+	 * to the same Microchip products.
+	 */
+	{
+		.compatible = "micrel,ksz8864",
+		.data = &ksz_switch_chips[KSZ8864]
+	},
+	{
+		.compatible = "micrel,ksz8795",
+		.data = &ksz_switch_chips[KSZ8795]
+	},
+	{
+		.compatible = "micrel,ks8995",
+		.data = &ksz_switch_chips[KSZ8995XA]
+	},
 	{
 		.compatible = "microchip,ksz8463",
 		.data = &ksz_switch_chips[KSZ8463]

@@ -256,6 +279,10 @@ static const struct of_device_id ksz_dt_ids[] = {
 		.compatible = "microchip,ksz8895",
 		.data = &ksz_switch_chips[KSZ8895]
 	},
+	{
+		.compatible = "microchip,ksz8995xa",
+		.data = &ksz_switch_chips[KSZ8995XA]
+	},
 	{
 		.compatible = "microchip,ksz9477",
 		.data = &ksz_switch_chips[KSZ9477]

@@ -317,6 +344,7 @@ static const struct of_device_id ksz_dt_ids[] = {
 MODULE_DEVICE_TABLE(of, ksz_dt_ids);
 
 static const struct spi_device_id ksz_spi_ids[] = {
+	{ "ks8995" },
 	{ "ksz8463" },
 	{ "ksz8765" },
 	{ "ksz8794" },

@@ -325,6 +353,7 @@ static const struct spi_device_id ksz_spi_ids[] = {
 	{ "ksz8864" },
 	{ "ksz8873" },
 	{ "ksz8895" },
+	{ "ksz8995" },
 	{ "ksz9477" },
 	{ "ksz9896" },
 	{ "ksz9897" },