Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

4 files changed, 1028 insertions, 0 deletions

diff --git a/drivers/net/can/slcan/Makefile b/drivers/net/can/slcan/Makefile
new file mode 100644
index 000000000..8a88e484e
--- /dev/null
+++ b/drivers/net/can/slcan/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_CAN_SLCAN) += slcan.o
+
+slcan-objs :=
+slcan-objs += slcan-core.o
+slcan-objs += slcan-ethtool.o
diff --git a/drivers/net/can/slcan/slcan-core.c b/drivers/net/can/slcan/slcan-core.c
new file mode 100644
index 000000000..f4db77007
--- /dev/null
+++ b/drivers/net/can/slcan/slcan-core.c
@@ -0,0 +1,941 @@
+/*
+ * slcan.c - serial line CAN interface driver (using tty line discipline)
+ *
+ * This file is derived from linux/drivers/net/slip/slip.c and got
+ * inspiration from linux/drivers/net/can/can327.c for the rework made
+ * on the line discipline code.
+ *
+ * slip.c Authors  : Laurence Culhane <loz@holmes.demon.co.uk>
+ *                   Fred N. van Kempen <waltje@uwalt.nl.mugnet.org>
+ * slcan.c Author  : Oliver Hartkopp <socketcan@hartkopp.net>
+ * can327.c Author : Max Staudt <max-linux@enpas.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see http://www.gnu.org/licenses/gpl.html
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+
+#include <linux/uaccess.h>
+#include <linux/bitops.h>
+#include <linux/string.h>
+#include <linux/tty.h>
+#include <linux/errno.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/rtnetlink.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/workqueue.h>
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include <linux/can/skb.h>
+
+#include "slcan.h"
+
+MODULE_ALIAS_LDISC(N_SLCAN);
+MODULE_DESCRIPTION("serial line CAN interface");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
+MODULE_AUTHOR("Dario Binacchi <dario.binacchi@amarulasolutions.com>");
+
+/* maximum rx buffer len: extended CAN frame with timestamp */
+#define SLCAN_MTU (sizeof("T1111222281122334455667788EA5F\r") + 1)
+
+#define SLCAN_CMD_LEN 1
+#define SLCAN_SFF_ID_LEN 3
+#define SLCAN_EFF_ID_LEN 8
+#define SLCAN_STATE_LEN 1
+#define SLCAN_STATE_BE_RXCNT_LEN 3
+#define SLCAN_STATE_BE_TXCNT_LEN 3
+#define SLCAN_STATE_FRAME_LEN       (1 + SLCAN_CMD_LEN + \
+				     SLCAN_STATE_BE_RXCNT_LEN + \
+				     SLCAN_STATE_BE_TXCNT_LEN)
+struct slcan {
+	struct can_priv         can;
+
+	/* Various fields. */
+	struct tty_struct	*tty;		/* ptr to TTY structure	     */
+	struct net_device	*dev;		/* easy for intr handling    */
+	spinlock_t		lock;
+	struct work_struct	tx_work;	/* Flushes transmit buffer   */
+
+	/* These are pointers to the malloc()ed frame buffers. */
+	unsigned char		rbuff[SLCAN_MTU];	/* receiver buffer   */
+	int			rcount;         /* received chars counter    */
+	unsigned char		xbuff[SLCAN_MTU];	/* transmitter buffer*/
+	unsigned char		*xhead;         /* pointer to next XMIT byte */
+	int			xleft;          /* bytes left in XMIT queue  */
+
+	unsigned long		flags;		/* Flag values/ mode etc     */
+#define SLF_ERROR		0               /* Parity, etc. error        */
+#define SLF_XCMD		1               /* Command transmission      */
+	unsigned long           cmd_flags;      /* Command flags             */
+#define CF_ERR_RST		0               /* Reset errors on open      */
+	wait_queue_head_t       xcmd_wait;      /* Wait queue for commands   */
+						/* transmission              */
+};
+
+static const u32 slcan_bitrate_const[] = {
+	10000, 20000, 50000, 100000, 125000,
+	250000, 500000, 800000, 1000000
+};
+
+bool slcan_err_rst_on_open(struct net_device *ndev)
+{
+	struct slcan *sl = netdev_priv(ndev);
+
+	return !!test_bit(CF_ERR_RST, &sl->cmd_flags);
+}
+
+int slcan_enable_err_rst_on_open(struct net_device *ndev, bool on)
+{
+	struct slcan *sl = netdev_priv(ndev);
+
+	if (netif_running(ndev))
+		return -EBUSY;
+
+	if (on)
+		set_bit(CF_ERR_RST, &sl->cmd_flags);
+	else
+		clear_bit(CF_ERR_RST, &sl->cmd_flags);
+
+	return 0;
+}
+
+/*************************************************************************
+ *			SLCAN ENCAPSULATION FORMAT			 *
+ *************************************************************************/
+
+/* A CAN frame has a can_id (11 bit standard frame format OR 29 bit extended
+ * frame format) a data length code (len) which can be from 0 to 8
+ * and up to <len> data bytes as payload.
+ * Additionally a CAN frame may become a remote transmission frame if the
+ * RTR-bit is set. This causes another ECU to send a CAN frame with the
+ * given can_id.
+ *
+ * The SLCAN ASCII representation of these different frame types is:
+ * <type> <id> <dlc> <data>*
+ *
+ * Extended frames (29 bit) are defined by capital characters in the type.
+ * RTR frames are defined as 'r' types - normal frames have 't' type:
+ * t => 11 bit data frame
+ * r => 11 bit RTR frame
+ * T => 29 bit data frame
+ * R => 29 bit RTR frame
+ *
+ * The <id> is 3 (standard) or 8 (extended) bytes in ASCII Hex (base64).
+ * The <dlc> is a one byte ASCII number ('0' - '8')
+ * The <data> section has at much ASCII Hex bytes as defined by the <dlc>
+ *
+ * Examples:
+ *
+ * t1230 : can_id 0x123, len 0, no data
+ * t4563112233 : can_id 0x456, len 3, data 0x11 0x22 0x33
+ * T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, len 2, data 0xAA 0x55
+ * r1230 : can_id 0x123, len 0, no data, remote transmission request
+ *
+ */
+
+/*************************************************************************
+ *			STANDARD SLCAN DECAPSULATION			 *
+ *************************************************************************/
+
+/* Send one completely decapsulated can_frame to the network layer */
+static void slcan_bump_frame(struct slcan *sl)
+{
+	struct sk_buff *skb;
+	struct can_frame *cf;
+	int i, tmp;
+	u32 tmpid;
+	char *cmd = sl->rbuff;
+
+	skb = alloc_can_skb(sl->dev, &cf);
+	if (unlikely(!skb)) {
+		sl->dev->stats.rx_dropped++;
+		return;
+	}
+
+	switch (*cmd) {
+	case 'r':
+		cf->can_id = CAN_RTR_FLAG;
+		fallthrough;
+	case 't':
+		/* store dlc ASCII value and terminate SFF CAN ID string */
+		cf->len = sl->rbuff[SLCAN_CMD_LEN + SLCAN_SFF_ID_LEN];
+		sl->rbuff[SLCAN_CMD_LEN + SLCAN_SFF_ID_LEN] = 0;
+		/* point to payload data behind the dlc */
+		cmd += SLCAN_CMD_LEN + SLCAN_SFF_ID_LEN + 1;
+		break;
+	case 'R':
+		cf->can_id = CAN_RTR_FLAG;
+		fallthrough;
+	case 'T':
+		cf->can_id |= CAN_EFF_FLAG;
+		/* store dlc ASCII value and terminate EFF CAN ID string */
+		cf->len = sl->rbuff[SLCAN_CMD_LEN + SLCAN_EFF_ID_LEN];
+		sl->rbuff[SLCAN_CMD_LEN + SLCAN_EFF_ID_LEN] = 0;
+		/* point to payload data behind the dlc */
+		cmd += SLCAN_CMD_LEN + SLCAN_EFF_ID_LEN + 1;
+		break;
+	default:
+		goto decode_failed;
+	}
+
+	if (kstrtou32(sl->rbuff + SLCAN_CMD_LEN, 16, &tmpid))
+		goto decode_failed;
+
+	cf->can_id |= tmpid;
+
+	/* get len from sanitized ASCII value */
+	if (cf->len >= '0' && cf->len < '9')
+		cf->len -= '0';
+	else
+		goto decode_failed;
+
+	/* RTR frames may have a dlc > 0 but they never have any data bytes */
+	if (!(cf->can_id & CAN_RTR_FLAG)) {
+		for (i = 0; i < cf->len; i++) {
+			tmp = hex_to_bin(*cmd++);
+			if (tmp < 0)
+				goto decode_failed;
+
+			cf->data[i] = (tmp << 4);
+			tmp = hex_to_bin(*cmd++);
+			if (tmp < 0)
+				goto decode_failed;
+
+			cf->data[i] |= tmp;
+		}
+	}
+
+	sl->dev->stats.rx_packets++;
+	if (!(cf->can_id & CAN_RTR_FLAG))
+		sl->dev->stats.rx_bytes += cf->len;
+
+	netif_rx(skb);
+	return;
+
+decode_failed:
+	sl->dev->stats.rx_errors++;
+	dev_kfree_skb(skb);
+}
+
+/* A change state frame must contain state info and receive and transmit
+ * error counters.
+ *
+ * Examples:
+ *
+ * sb256256 : state bus-off: rx counter 256, tx counter 256
+ * sa057033 : state active, rx counter 57, tx counter 33
+ */
+static void slcan_bump_state(struct slcan *sl)
+{
+	struct net_device *dev = sl->dev;
+	struct sk_buff *skb;
+	struct can_frame *cf;
+	char *cmd = sl->rbuff;
+	u32 rxerr, txerr;
+	enum can_state state, rx_state, tx_state;
+
+	switch (cmd[1]) {
+	case 'a':
+		state = CAN_STATE_ERROR_ACTIVE;
+		break;
+	case 'w':
+		state = CAN_STATE_ERROR_WARNING;
+		break;
+	case 'p':
+		state = CAN_STATE_ERROR_PASSIVE;
+		break;
+	case 'b':
+		state = CAN_STATE_BUS_OFF;
+		break;
+	default:
+		return;
+	}
+
+	if (state == sl->can.state || sl->rcount < SLCAN_STATE_FRAME_LEN)
+		return;
+
+	cmd += SLCAN_STATE_BE_RXCNT_LEN + SLCAN_CMD_LEN + 1;
+	cmd[SLCAN_STATE_BE_TXCNT_LEN] = 0;
+	if (kstrtou32(cmd, 10, &txerr))
+		return;
+
+	*cmd = 0;
+	cmd -= SLCAN_STATE_BE_RXCNT_LEN;
+	if (kstrtou32(cmd, 10, &rxerr))
+		return;
+
+	skb = alloc_can_err_skb(dev, &cf);
+
+	tx_state = txerr >= rxerr ? state : 0;
+	rx_state = txerr <= rxerr ? state : 0;
+	can_change_state(dev, cf, tx_state, rx_state);
+
+	if (state == CAN_STATE_BUS_OFF) {
+		can_bus_off(dev);
+	} else if (skb) {
+		cf->can_id |= CAN_ERR_CNT;
+		cf->data[6] = txerr;
+		cf->data[7] = rxerr;
+	}
+
+	if (skb)
+		netif_rx(skb);
+}
+
+/* An error frame can contain more than one type of error.
+ *
+ * Examples:
+ *
+ * e1a : len 1, errors: ACK error
+ * e3bcO: len 3, errors: Bit0 error, CRC error, Tx overrun error
+ */
+static void slcan_bump_err(struct slcan *sl)
+{
+	struct net_device *dev = sl->dev;
+	struct sk_buff *skb;
+	struct can_frame *cf;
+	char *cmd = sl->rbuff;
+	bool rx_errors = false, tx_errors = false, rx_over_errors = false;
+	int i, len;
+
+	/* get len from sanitized ASCII value */
+	len = cmd[1];
+	if (len >= '0' && len < '9')
+		len -= '0';
+	else
+		return;
+
+	if ((len + SLCAN_CMD_LEN + 1) > sl->rcount)
+		return;
+
+	skb = alloc_can_err_skb(dev, &cf);
+
+	if (skb)
+		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+
+	cmd += SLCAN_CMD_LEN + 1;
+	for (i = 0; i < len; i++, cmd++) {
+		switch (*cmd) {
+		case 'a':
+			netdev_dbg(dev, "ACK error\n");
+			tx_errors = true;
+			if (skb) {
+				cf->can_id |= CAN_ERR_ACK;
+				cf->data[3] = CAN_ERR_PROT_LOC_ACK;
+			}
+
+			break;
+		case 'b':
+			netdev_dbg(dev, "Bit0 error\n");
+			tx_errors = true;
+			if (skb)
+				cf->data[2] |= CAN_ERR_PROT_BIT0;
+
+			break;
+		case 'B':
+			netdev_dbg(dev, "Bit1 error\n");
+			tx_errors = true;
+			if (skb)
+				cf->data[2] |= CAN_ERR_PROT_BIT1;
+
+			break;
+		case 'c':
+			netdev_dbg(dev, "CRC error\n");
+			rx_errors = true;
+			if (skb) {
+				cf->data[2] |= CAN_ERR_PROT_BIT;
+				cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
+			}
+
+			break;
+		case 'f':
+			netdev_dbg(dev, "Form Error\n");
+			rx_errors = true;
+			if (skb)
+				cf->data[2] |= CAN_ERR_PROT_FORM;
+
+			break;
+		case 'o':
+			netdev_dbg(dev, "Rx overrun error\n");
+			rx_over_errors = true;
+			rx_errors = true;
+			if (skb) {
+				cf->can_id |= CAN_ERR_CRTL;
+				cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+			}
+
+			break;
+		case 'O':
+			netdev_dbg(dev, "Tx overrun error\n");
+			tx_errors = true;
+			if (skb) {
+				cf->can_id |= CAN_ERR_CRTL;
+				cf->data[1] = CAN_ERR_CRTL_TX_OVERFLOW;
+			}
+
+			break;
+		case 's':
+			netdev_dbg(dev, "Stuff error\n");
+			rx_errors = true;
+			if (skb)
+				cf->data[2] |= CAN_ERR_PROT_STUFF;
+
+			break;
+		default:
+			if (skb)
+				dev_kfree_skb(skb);
+
+			return;
+		}
+	}
+
+	if (rx_errors)
+		dev->stats.rx_errors++;
+
+	if (rx_over_errors)
+		dev->stats.rx_over_errors++;
+
+	if (tx_errors)
+		dev->stats.tx_errors++;
+
+	if (skb)
+		netif_rx(skb);
+}
+
+static void slcan_bump(struct slcan *sl)
+{
+	switch (sl->rbuff[0]) {
+	case 'r':
+		fallthrough;
+	case 't':
+		fallthrough;
+	case 'R':
+		fallthrough;
+	case 'T':
+		return slcan_bump_frame(sl);
+	case 'e':
+		return slcan_bump_err(sl);
+	case 's':
+		return slcan_bump_state(sl);
+	default:
+		return;
+	}
+}
+
+/* parse tty input stream */
+static void slcan_unesc(struct slcan *sl, unsigned char s)
+{
+	if ((s == '\r') || (s == '\a')) { /* CR or BEL ends the pdu */
+		if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
+		    sl->rcount > 4)
+			slcan_bump(sl);
+
+		sl->rcount = 0;
+	} else {
+		if (!test_bit(SLF_ERROR, &sl->flags))  {
+			if (sl->rcount < SLCAN_MTU)  {
+				sl->rbuff[sl->rcount++] = s;
+				return;
+			}
+
+			sl->dev->stats.rx_over_errors++;
+			set_bit(SLF_ERROR, &sl->flags);
+		}
+	}
+}
+
+/*************************************************************************
+ *			STANDARD SLCAN ENCAPSULATION			 *
+ *************************************************************************/
+
+/* Encapsulate one can_frame and stuff into a TTY queue. */
+static void slcan_encaps(struct slcan *sl, struct can_frame *cf)
+{
+	int actual, i;
+	unsigned char *pos;
+	unsigned char *endpos;
+	canid_t id = cf->can_id;
+
+	pos = sl->xbuff;
+
+	if (cf->can_id & CAN_RTR_FLAG)
+		*pos = 'R'; /* becomes 'r' in standard frame format (SFF) */
+	else
+		*pos = 'T'; /* becomes 't' in standard frame format (SSF) */
+
+	/* determine number of chars for the CAN-identifier */
+	if (cf->can_id & CAN_EFF_FLAG) {
+		id &= CAN_EFF_MASK;
+		endpos = pos + SLCAN_EFF_ID_LEN;
+	} else {
+		*pos |= 0x20; /* convert R/T to lower case for SFF */
+		id &= CAN_SFF_MASK;
+		endpos = pos + SLCAN_SFF_ID_LEN;
+	}
+
+	/* build 3 (SFF) or 8 (EFF) digit CAN identifier */
+	pos++;
+	while (endpos >= pos) {
+		*endpos-- = hex_asc_upper[id & 0xf];
+		id >>= 4;
+	}
+
+	pos += (cf->can_id & CAN_EFF_FLAG) ?
+		SLCAN_EFF_ID_LEN : SLCAN_SFF_ID_LEN;
+
+	*pos++ = cf->len + '0';
+
+	/* RTR frames may have a dlc > 0 but they never have any data bytes */
+	if (!(cf->can_id & CAN_RTR_FLAG)) {
+		for (i = 0; i < cf->len; i++)
+			pos = hex_byte_pack_upper(pos, cf->data[i]);
+
+		sl->dev->stats.tx_bytes += cf->len;
+	}
+
+	*pos++ = '\r';
+
+	/* Order of next two lines is *very* important.
+	 * When we are sending a little amount of data,
+	 * the transfer may be completed inside the ops->write()
+	 * routine, because it's running with interrupts enabled.
+	 * In this case we *never* got WRITE_WAKEUP event,
+	 * if we did not request it before write operation.
+	 *       14 Oct 1994  Dmitry Gorodchanin.
+	 */
+	set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
+	actual = sl->tty->ops->write(sl->tty, sl->xbuff, pos - sl->xbuff);
+	sl->xleft = (pos - sl->xbuff) - actual;
+	sl->xhead = sl->xbuff + actual;
+}
+
+/* Write out any remaining transmit buffer. Scheduled when tty is writable */
+static void slcan_transmit(struct work_struct *work)
+{
+	struct slcan *sl = container_of(work, struct slcan, tx_work);
+	int actual;
+
+	spin_lock_bh(&sl->lock);
+	/* First make sure we're connected. */
+	if (unlikely(!netif_running(sl->dev)) &&
+	    likely(!test_bit(SLF_XCMD, &sl->flags))) {
+		spin_unlock_bh(&sl->lock);
+		return;
+	}
+
+	if (sl->xleft <= 0)  {
+		if (unlikely(test_bit(SLF_XCMD, &sl->flags))) {
+			clear_bit(SLF_XCMD, &sl->flags);
+			clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
+			spin_unlock_bh(&sl->lock);
+			wake_up(&sl->xcmd_wait);
+			return;
+		}
+
+		/* Now serial buffer is almost free & we can start
+		 * transmission of another packet
+		 */
+		sl->dev->stats.tx_packets++;
+		clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
+		spin_unlock_bh(&sl->lock);
+		netif_wake_queue(sl->dev);
+		return;
+	}
+
+	actual = sl->tty->ops->write(sl->tty, sl->xhead, sl->xleft);
+	sl->xleft -= actual;
+	sl->xhead += actual;
+	spin_unlock_bh(&sl->lock);
+}
+
+/* Called by the driver when there's room for more data.
+ * Schedule the transmit.
+ */
+static void slcan_write_wakeup(struct tty_struct *tty)
+{
+	struct slcan *sl = (struct slcan *)tty->disc_data;
+
+	schedule_work(&sl->tx_work);
+}
+
+/* Send a can_frame to a TTY queue. */
+static netdev_tx_t slcan_netdev_xmit(struct sk_buff *skb,
+				     struct net_device *dev)
+{
+	struct slcan *sl = netdev_priv(dev);
+
+	if (can_dev_dropped_skb(dev, skb))
+		return NETDEV_TX_OK;
+
+	spin_lock(&sl->lock);
+	if (!netif_running(dev))  {
+		spin_unlock(&sl->lock);
+		netdev_warn(dev, "xmit: iface is down\n");
+		goto out;
+	}
+	if (!sl->tty) {
+		spin_unlock(&sl->lock);
+		goto out;
+	}
+
+	netif_stop_queue(sl->dev);
+	slcan_encaps(sl, (struct can_frame *)skb->data); /* encaps & send */
+	spin_unlock(&sl->lock);
+
+	skb_tx_timestamp(skb);
+
+out:
+	kfree_skb(skb);
+	return NETDEV_TX_OK;
+}
+
+/******************************************
+ *   Routines looking at netdevice side.
+ ******************************************/
+
+static int slcan_transmit_cmd(struct slcan *sl, const unsigned char *cmd)
+{
+	int ret, actual, n;
+
+	spin_lock(&sl->lock);
+	if (!sl->tty) {
+		spin_unlock(&sl->lock);
+		return -ENODEV;
+	}
+
+	n = scnprintf(sl->xbuff, sizeof(sl->xbuff), "%s", cmd);
+	set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
+	actual = sl->tty->ops->write(sl->tty, sl->xbuff, n);
+	sl->xleft = n - actual;
+	sl->xhead = sl->xbuff + actual;
+	set_bit(SLF_XCMD, &sl->flags);
+	spin_unlock(&sl->lock);
+	ret = wait_event_interruptible_timeout(sl->xcmd_wait,
+					       !test_bit(SLF_XCMD, &sl->flags),
+					       HZ);
+	clear_bit(SLF_XCMD, &sl->flags);
+	if (ret == -ERESTARTSYS)
+		return ret;
+
+	if (ret == 0)
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+/* Netdevice UP -> DOWN routine */
+static int slcan_netdev_close(struct net_device *dev)
+{
+	struct slcan *sl = netdev_priv(dev);
+	int err;
+
+	if (sl->can.bittiming.bitrate &&
+	    sl->can.bittiming.bitrate != CAN_BITRATE_UNKNOWN) {
+		err = slcan_transmit_cmd(sl, "C\r");
+		if (err)
+			netdev_warn(dev,
+				    "failed to send close command 'C\\r'\n");
+	}
+
+	/* TTY discipline is running. */
+	clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
+	flush_work(&sl->tx_work);
+
+	netif_stop_queue(dev);
+	sl->rcount   = 0;
+	sl->xleft    = 0;
+	close_candev(dev);
+	sl->can.state = CAN_STATE_STOPPED;
+	if (sl->can.bittiming.bitrate == CAN_BITRATE_UNKNOWN)
+		sl->can.bittiming.bitrate = CAN_BITRATE_UNSET;
+
+	return 0;
+}
+
+/* Netdevice DOWN -> UP routine */
+static int slcan_netdev_open(struct net_device *dev)
+{
+	struct slcan *sl = netdev_priv(dev);
+	unsigned char cmd[SLCAN_MTU];
+	int err, s;
+
+	/* The baud rate is not set with the command
+	 * `ip link set <iface> type can bitrate <baud>' and therefore
+	 * can.bittiming.bitrate is CAN_BITRATE_UNSET (0), causing
+	 * open_candev() to fail. So let's set to a fake value.
+	 */
+	if (sl->can.bittiming.bitrate == CAN_BITRATE_UNSET)
+		sl->can.bittiming.bitrate = CAN_BITRATE_UNKNOWN;
+
+	err = open_candev(dev);
+	if (err) {
+		netdev_err(dev, "failed to open can device\n");
+		return err;
+	}
+
+	if (sl->can.bittiming.bitrate != CAN_BITRATE_UNKNOWN) {
+		for (s = 0; s < ARRAY_SIZE(slcan_bitrate_const); s++) {
+			if (sl->can.bittiming.bitrate == slcan_bitrate_const[s])
+				break;
+		}
+
+		/* The CAN framework has already validate the bitrate value,
+		 * so we can avoid to check if `s' has been properly set.
+		 */
+		snprintf(cmd, sizeof(cmd), "C\rS%d\r", s);
+		err = slcan_transmit_cmd(sl, cmd);
+		if (err) {
+			netdev_err(dev,
+				   "failed to send bitrate command 'C\\rS%d\\r'\n",
+				   s);
+			goto cmd_transmit_failed;
+		}
+
+		if (test_bit(CF_ERR_RST, &sl->cmd_flags)) {
+			err = slcan_transmit_cmd(sl, "F\r");
+			if (err) {
+				netdev_err(dev,
+					   "failed to send error command 'F\\r'\n");
+				goto cmd_transmit_failed;
+			}
+		}
+
+		if (sl->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) {
+			err = slcan_transmit_cmd(sl, "L\r");
+			if (err) {
+				netdev_err(dev,
+					   "failed to send listen-only command 'L\\r'\n");
+				goto cmd_transmit_failed;
+			}
+		} else {
+			err = slcan_transmit_cmd(sl, "O\r");
+			if (err) {
+				netdev_err(dev,
+					   "failed to send open command 'O\\r'\n");
+				goto cmd_transmit_failed;
+			}
+		}
+	}
+
+	sl->can.state = CAN_STATE_ERROR_ACTIVE;
+	netif_start_queue(dev);
+	return 0;
+
+cmd_transmit_failed:
+	close_candev(dev);
+	return err;
+}
+
+static const struct net_device_ops slcan_netdev_ops = {
+	.ndo_open               = slcan_netdev_open,
+	.ndo_stop               = slcan_netdev_close,
+	.ndo_start_xmit         = slcan_netdev_xmit,
+	.ndo_change_mtu         = can_change_mtu,
+};
+
+/******************************************
+ *  Routines looking at TTY side.
+ ******************************************/
+
+/* Handle the 'receiver data ready' interrupt.
+ * This function is called by the 'tty_io' module in the kernel when
+ * a block of SLCAN data has been received, which can now be decapsulated
+ * and sent on to some IP layer for further processing. This will not
+ * be re-entered while running but other ldisc functions may be called
+ * in parallel
+ */
+static void slcan_receive_buf(struct tty_struct *tty,
+			      const unsigned char *cp, const char *fp,
+			      int count)
+{
+	struct slcan *sl = (struct slcan *)tty->disc_data;
+
+	if (!netif_running(sl->dev))
+		return;
+
+	/* Read the characters out of the buffer */
+	while (count--) {
+		if (fp && *fp++) {
+			if (!test_and_set_bit(SLF_ERROR, &sl->flags))
+				sl->dev->stats.rx_errors++;
+			cp++;
+			continue;
+		}
+		slcan_unesc(sl, *cp++);
+	}
+}
+
+/* Open the high-level part of the SLCAN channel.
+ * This function is called by the TTY module when the
+ * SLCAN line discipline is called for.
+ *
+ * Called in process context serialized from other ldisc calls.
+ */
+static int slcan_open(struct tty_struct *tty)
+{
+	struct net_device *dev;
+	struct slcan *sl;
+	int err;
+
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
+	if (!tty->ops->write)
+		return -EOPNOTSUPP;
+
+	dev = alloc_candev(sizeof(*sl), 1);
+	if (!dev)
+		return -ENFILE;
+
+	sl = netdev_priv(dev);
+
+	/* Configure TTY interface */
+	tty->receive_room = 65536; /* We don't flow control */
+	sl->rcount = 0;
+	sl->xleft = 0;
+	spin_lock_init(&sl->lock);
+	INIT_WORK(&sl->tx_work, slcan_transmit);
+	init_waitqueue_head(&sl->xcmd_wait);
+
+	/* Configure CAN metadata */
+	sl->can.bitrate_const = slcan_bitrate_const;
+	sl->can.bitrate_const_cnt = ARRAY_SIZE(slcan_bitrate_const);
+	sl->can.ctrlmode_supported = CAN_CTRLMODE_LISTENONLY;
+
+	/* Configure netdev interface */
+	sl->dev	= dev;
+	dev->netdev_ops = &slcan_netdev_ops;
+	dev->ethtool_ops = &slcan_ethtool_ops;
+
+	/* Mark ldisc channel as alive */
+	sl->tty = tty;
+	tty->disc_data = sl;
+
+	err = register_candev(dev);
+	if (err) {
+		free_candev(dev);
+		pr_err("can't register candev\n");
+		return err;
+	}
+
+	netdev_info(dev, "slcan on %s.\n", tty->name);
+	/* TTY layer expects 0 on success */
+	return 0;
+}
+
+/* Close down a SLCAN channel.
+ * This means flushing out any pending queues, and then returning. This
+ * call is serialized against other ldisc functions.
+ * Once this is called, no other ldisc function of ours is entered.
+ *
+ * We also use this method for a hangup event.
+ */
+static void slcan_close(struct tty_struct *tty)
+{
+	struct slcan *sl = (struct slcan *)tty->disc_data;
+
+	unregister_candev(sl->dev);
+
+	/*
+	 * The netdev needn't be UP (so .ndo_stop() is not called). Hence make
+	 * sure this is not running before freeing it up.
+	 */
+	flush_work(&sl->tx_work);
+
+	/* Mark channel as dead */
+	spin_lock_bh(&sl->lock);
+	tty->disc_data = NULL;
+	sl->tty = NULL;
+	spin_unlock_bh(&sl->lock);
+
+	netdev_info(sl->dev, "slcan off %s.\n", tty->name);
+	free_candev(sl->dev);
+}
+
+/* Perform I/O control on an active SLCAN channel. */
+static int slcan_ioctl(struct tty_struct *tty, unsigned int cmd,
+		       unsigned long arg)
+{
+	struct slcan *sl = (struct slcan *)tty->disc_data;
+	unsigned int tmp;
+
+	switch (cmd) {
+	case SIOCGIFNAME:
+		tmp = strlen(sl->dev->name) + 1;
+		if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
+			return -EFAULT;
+		return 0;
+
+	case SIOCSIFHWADDR:
+		return -EINVAL;
+
+	default:
+		return tty_mode_ioctl(tty, cmd, arg);
+	}
+}
+
+static struct tty_ldisc_ops slcan_ldisc = {
+	.owner		= THIS_MODULE,
+	.num		= N_SLCAN,
+	.name		= KBUILD_MODNAME,
+	.open		= slcan_open,
+	.close		= slcan_close,
+	.ioctl		= slcan_ioctl,
+	.receive_buf	= slcan_receive_buf,
+	.write_wakeup	= slcan_write_wakeup,
+};
+
+static int __init slcan_init(void)
+{
+	int status;
+
+	pr_info("serial line CAN interface driver\n");
+
+	/* Fill in our line protocol discipline, and register it */
+	status = tty_register_ldisc(&slcan_ldisc);
+	if (status)
+		pr_err("can't register line discipline\n");
+
+	return status;
+}
+
+static void __exit slcan_exit(void)
+{
+	/* This will only be called when all channels have been closed by
+	 * userspace - tty_ldisc.c takes care of the module's refcount.
+	 */
+	tty_unregister_ldisc(&slcan_ldisc);
+}
+
+module_init(slcan_init);
+module_exit(slcan_exit);
diff --git a/drivers/net/can/slcan/slcan-ethtool.c b/drivers/net/can/slcan/slcan-ethtool.c
new file mode 100644
index 000000000..f598c653f
--- /dev/null
+++ b/drivers/net/can/slcan/slcan-ethtool.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Copyright (c) 2022 Amarula Solutions, Dario Binacchi <dario.binacchi@amarulasolutions.com>
+ *
+ */
+
+#include <linux/can/dev.h>
+#include <linux/ethtool.h>
+#include <linux/kernel.h>
+#include <linux/netdevice.h>
+#include <linux/platform_device.h>
+
+#include "slcan.h"
+
+static const char slcan_priv_flags_strings[][ETH_GSTRING_LEN] = {
+#define SLCAN_PRIV_FLAGS_ERR_RST_ON_OPEN BIT(0)
+	"err-rst-on-open",
+};
+
+static void slcan_get_strings(struct net_device *ndev, u32 stringset, u8 *data)
+{
+	switch (stringset) {
+	case ETH_SS_PRIV_FLAGS:
+		memcpy(data, slcan_priv_flags_strings,
+		       sizeof(slcan_priv_flags_strings));
+	}
+}
+
+static u32 slcan_get_priv_flags(struct net_device *ndev)
+{
+	u32 flags = 0;
+
+	if (slcan_err_rst_on_open(ndev))
+		flags |= SLCAN_PRIV_FLAGS_ERR_RST_ON_OPEN;
+
+	return flags;
+}
+
+static int slcan_set_priv_flags(struct net_device *ndev, u32 flags)
+{
+	bool err_rst_op_open = !!(flags & SLCAN_PRIV_FLAGS_ERR_RST_ON_OPEN);
+
+	return slcan_enable_err_rst_on_open(ndev, err_rst_op_open);
+}
+
+static int slcan_get_sset_count(struct net_device *netdev, int sset)
+{
+	switch (sset) {
+	case ETH_SS_PRIV_FLAGS:
+		return ARRAY_SIZE(slcan_priv_flags_strings);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+const struct ethtool_ops slcan_ethtool_ops = {
+	.get_strings = slcan_get_strings,
+	.get_priv_flags = slcan_get_priv_flags,
+	.set_priv_flags = slcan_set_priv_flags,
+	.get_sset_count = slcan_get_sset_count,
+	.get_ts_info = ethtool_op_get_ts_info,
+};
diff --git a/drivers/net/can/slcan/slcan.h b/drivers/net/can/slcan/slcan.h
new file mode 100644
index 000000000..85cedf856
--- /dev/null
+++ b/drivers/net/can/slcan/slcan.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0
+ * slcan.h - serial line CAN interface driver
+ *
+ * Copyright (C) Laurence Culhane <loz@holmes.demon.co.uk>
+ * Copyright (C) Fred N. van Kempen <waltje@uwalt.nl.mugnet.org>
+ * Copyright (C) Oliver Hartkopp <socketcan@hartkopp.net>
+ * Copyright (C) 2022 Amarula Solutions, Dario Binacchi <dario.binacchi@amarulasolutions.com>
+ *
+ */
+
+#ifndef _SLCAN_H
+#define _SLCAN_H
+
+bool slcan_err_rst_on_open(struct net_device *ndev);
+int slcan_enable_err_rst_on_open(struct net_device *ndev, bool on);
+
+extern const struct ethtool_ops slcan_ethtool_ops;
+
+#endif /* _SLCAN_H */