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From:   "Ji-Ze Hong (Peter Hong)" <peter_hong@fintek.com.tw>
To:     <wg@grandegger.com>, <mkl@pengutronix.de>,
        <michal.swiatkowski@linux.intel.com>,
        <Steen.Hegelund@microchip.com>, <mailhol.vincent@wanadoo.fr>
CC:     <davem@davemloft.net>, <edumazet@google.com>, <kuba@kernel.org>,
        <pabeni@redhat.com>, <frank.jungclaus@esd.eu>,
        <linux-kernel@vger.kernel.org>, <linux-can@vger.kernel.org>,
        <netdev@vger.kernel.org>, <hpeter+linux_kernel@gmail.com>,
        "Ji-Ze Hong (Peter Hong)" <peter_hong@fintek.com.tw>
Subject: [PATCH V7] can: usb: f81604: add Fintek F81604 support
Date:   Tue, 9 May 2023 15:38:21 +0800
Message-ID: <20230509073821.25289-1-peter_hong@fintek.com.tw>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

This patch adds support for Fintek USB to 2CAN controller.

Signed-off-by: Ji-Ze Hong (Peter Hong) <peter_hong@fintek.com.tw>
---
Changelog:
v7:
	1. Fix consistency of coding style for "break" in f81604_register_urbs().
	2. Remove goto statement in f81604_open().

v6:
	1. Remove non-used define and change constant mask to GENMASK().
	2. Move some variables declaration from function start to block start.
	3. Move some variables initization into declaration.
	4. Change variable "id" in f81604_start_xmit() only for CAN ID usage.

v5:
	1. Change all u8 *buff to struct f81604_int_data/f81604_can_frame.
	2. Change all netdev->dev_id to netdev->dev_port.
	3. Remove over design for f81604_process_rx_packet(). This device only
	   report a frame at once, so the f81604_process_rx_packet() are reduced
	   to process 1 frame.

v4:
	1. Remove f81604_prepare_urbs/f81604_remove_urbs() and alloc URB/buffer
	   dynamically in f81604_register_urbs(), using "urbs_anchor" for manage
	   all rx/int URBs.
	2. Add F81604 to MAINTAINERS list.
	3. Change handle_clear_reg_work/handle_clear_overrun_work to single
	   clear_reg_work and using bitwise "clear_flags" to record it.
	4. Move __f81604_set_termination in front of f81604_probe() to avoid
	   rarely racing condition.
	5. Add __aligned to struct f81604_int_data / f81604_sff / f81604_eff.
	6. Add aligned operations in f81604_start_xmit/f81604_process_rx_packet().
	7. Change lots of CANBUS functions first parameter from struct usb_device*
	   to struct f81604_port_priv *priv. But remain f81604_write / f81604_read
	   / f81604_update_bits() as struct usb_device* for
	   __f81604_set_termination() in probe() stage.
	8. Simplify f81604_read_int_callback() and separate into
	   f81604_handle_tx / f81604_handle_can_bus_errors() functions.

v3:
	1. Change CAN clock to using MEGA units.
	2. Remove USB set/get retry, only remain SJA1000 reset/operation retry.
	3. Fix all numberic constant to define.
	4. Add terminator control. (only 0 & 120 ohm)
	5. Using struct data to represent INT/TX/RX endpoints data instead byte
	   arrays.
	6. Error message reports changed from %d to %pe for mnemotechnic values.
	7. Some bit operations are changed to FIELD_PREP().
	8. Separate TX functions from f81604_read_int_callback().
	9. cf->can_id |= CAN_ERR_CNT in f81604_read_int_callback to report valid
	   TX/RX error counts.
	10. Move f81604_prepare_urbs/f81604_remove_urbs() from CAN open/close() to
	    USB probe/disconnect().
	11. coding style refactoring.

v2:
	1. coding style refactoring.
	2. some const number are defined to describe itself.
	3. fix wrong usage for can_get_echo_skb() in f81604_write_bulk_callback().

 MAINTAINERS                  |    6 +
 drivers/net/can/usb/Kconfig  |   12 +
 drivers/net/can/usb/Makefile |    1 +
 drivers/net/can/usb/f81604.c | 1201 ++++++++++++++++++++++++++++++++++
 4 files changed, 1220 insertions(+)
 create mode 100644 drivers/net/can/usb/f81604.c

diff --git a/MAINTAINERS b/MAINTAINERS
index f375bbf3bc80..fa573f637c2f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8058,6 +8058,12 @@ S:	Maintained
 F:	drivers/hwmon/f75375s.c
 F:	include/linux/f75375s.h
 
+FINTEK F81604 USB to 2xCANBUS DEVICE DRIVER
+M:	Ji-Ze Hong (Peter Hong) <peter_hong@fintek.com.tw>
+L:	linux-can@vger.kernel.org
+S:	Maintained
+F:	drivers/net/can/usb/f81604.c
+
 FIREWIRE AUDIO DRIVERS and IEC 61883-1/6 PACKET STREAMING ENGINE
 M:	Clemens Ladisch <clemens@ladisch.de>
 M:	Takashi Sakamoto <o-takashi@sakamocchi.jp>
diff --git a/drivers/net/can/usb/Kconfig b/drivers/net/can/usb/Kconfig
index 445504ababce..58fcd2b34820 100644
--- a/drivers/net/can/usb/Kconfig
+++ b/drivers/net/can/usb/Kconfig
@@ -38,6 +38,18 @@ config CAN_ETAS_ES58X
 	  To compile this driver as a module, choose M here: the module
 	  will be called etas_es58x.
 
+config CAN_F81604
+        tristate "Fintek F81604 USB to 2CAN interface"
+        help
+          This driver supports the Fintek F81604 USB to 2CAN interface.
+          The device can support CAN2.0A/B protocol and also support
+          2 output pins to control external terminator (optional).
+
+          To compile this driver as a module, choose M here: the module will
+          be called f81604.
+
+          (see also https://www.fintek.com.tw).
+
 config CAN_GS_USB
 	tristate "Geschwister Schneider UG and candleLight compatible interfaces"
 	help
diff --git a/drivers/net/can/usb/Makefile b/drivers/net/can/usb/Makefile
index 1ea16be5743b..8b11088e9a59 100644
--- a/drivers/net/can/usb/Makefile
+++ b/drivers/net/can/usb/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_CAN_8DEV_USB) += usb_8dev.o
 obj-$(CONFIG_CAN_EMS_USB) += ems_usb.o
 obj-$(CONFIG_CAN_ESD_USB) += esd_usb.o
 obj-$(CONFIG_CAN_ETAS_ES58X) += etas_es58x/
+obj-$(CONFIG_CAN_F81604) += f81604.o
 obj-$(CONFIG_CAN_GS_USB) += gs_usb.o
 obj-$(CONFIG_CAN_KVASER_USB) += kvaser_usb/
 obj-$(CONFIG_CAN_MCBA_USB) += mcba_usb.o
diff --git a/drivers/net/can/usb/f81604.c b/drivers/net/can/usb/f81604.c
new file mode 100644
index 000000000000..c1ecd3a54431
--- /dev/null
+++ b/drivers/net/can/usb/f81604.c
@@ -0,0 +1,1201 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Fintek F81604 USB-to-2CAN controller driver.
+ *
+ * Copyright (C) 2023 Ji-Ze Hong (Peter Hong) <peter_hong@fintek.com.tw>
+ */
+#include <linux/bitfield.h>
+#include <linux/netdevice.h>
+#include <linux/units.h>
+#include <linux/usb.h>
+
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include <linux/can/error.h>
+#include <linux/can/platform/sja1000.h>
+
+#include <asm-generic/unaligned.h>
+
+/* vendor and product id */
+#define F81604_VENDOR_ID 0x2c42
+#define F81604_PRODUCT_ID 0x1709
+#define F81604_CAN_CLOCK (12 * MEGA)
+#define F81604_MAX_DEV 2
+#define F81604_SET_DEVICE_RETRY 10
+
+#define F81604_USB_TIMEOUT 2000
+#define F81604_SET_GET_REGISTER 0xA0
+#define F81604_PORT_OFFSET 0x1000
+#define F81604_MAX_RX_URBS 4
+
+#define F81604_CMD_DATA 0x00
+
+#define F81604_DLC_LEN_MASK GENMASK(3, 0)
+#define F81604_DLC_EFF_BIT BIT(7)
+#define F81604_DLC_RTR_BIT BIT(6)
+
+#define F81604_SFF_SHIFT 5
+#define F81604_EFF_SHIFT 3
+
+#define F81604_BRP_MASK GENMASK(5, 0)
+#define F81604_SJW_MASK GENMASK(7, 6)
+
+#define F81604_SEG1_MASK GENMASK(3, 0)
+#define F81604_SEG2_MASK GENMASK(6, 4)
+
+#define F81604_CLEAR_ALC 0
+#define F81604_CLEAR_ECC 1
+#define F81604_CLEAR_OVERRUN 2
+
+/* device setting */
+#define F81604_CTRL_MODE_REG 0x80
+#define F81604_TX_ONESHOT (0x03 << 3)
+#define F81604_TX_NORMAL (0x01 << 3)
+#define F81604_RX_AUTO_RELEASE_BUF BIT(1)
+#define F81604_INT_WHEN_CHANGE BIT(0)
+
+#define F81604_TERMINATOR_REG 0x105
+#define F81604_CAN0_TERM BIT(2)
+#define F81604_CAN1_TERM BIT(3)
+
+#define F81604_TERMINATION_DISABLED CAN_TERMINATION_DISABLED
+#define F81604_TERMINATION_ENABLED 120
+
+/* SJA1000 registers - manual section 6.4 (Pelican Mode) */
+#define F81604_SJA1000_MOD 0x00
+#define F81604_SJA1000_CMR 0x01
+#define F81604_SJA1000_IR 0x03
+#define F81604_SJA1000_IER 0x04
+#define F81604_SJA1000_ALC 0x0B
+#define F81604_SJA1000_ECC 0x0C
+#define F81604_SJA1000_RXERR 0x0E
+#define F81604_SJA1000_TXERR 0x0F
+#define F81604_SJA1000_ACCC0 0x10
+#define F81604_SJA1000_ACCM0 0x14
+#define F81604_MAX_FILTER_CNT 4
+
+/* Common registers - manual section 6.5 */
+#define F81604_SJA1000_BTR0 0x06
+#define F81604_SJA1000_BTR1 0x07
+#define F81604_SJA1000_BTR1_SAMPLE_TRIPLE BIT(7)
+#define F81604_SJA1000_OCR 0x08
+#define F81604_SJA1000_CDR 0x1F
+
+/* mode register */
+#define F81604_SJA1000_MOD_RM 0x01
+#define F81604_SJA1000_MOD_LOM 0x02
+#define F81604_SJA1000_MOD_STM 0x04
+
+/* commands */
+#define F81604_SJA1000_CMD_CDO 0x08
+
+/* interrupt sources */
+#define F81604_SJA1000_IRQ_BEI 0x80
+#define F81604_SJA1000_IRQ_ALI 0x40
+#define F81604_SJA1000_IRQ_EPI 0x20
+#define F81604_SJA1000_IRQ_DOI 0x08
+#define F81604_SJA1000_IRQ_EI 0x04
+#define F81604_SJA1000_IRQ_TI 0x02
+#define F81604_SJA1000_IRQ_RI 0x01
+#define F81604_SJA1000_IRQ_ALL 0xFF
+#define F81604_SJA1000_IRQ_OFF 0x00
+
+/* status register content */
+#define F81604_SJA1000_SR_BS 0x80
+#define F81604_SJA1000_SR_ES 0x40
+#define F81604_SJA1000_SR_TCS 0x08
+
+/* ECC register */
+#define F81604_SJA1000_ECC_SEG 0x1F
+#define F81604_SJA1000_ECC_DIR 0x20
+#define F81604_SJA1000_ECC_BIT 0x00
+#define F81604_SJA1000_ECC_FORM 0x40
+#define F81604_SJA1000_ECC_STUFF 0x80
+#define F81604_SJA1000_ECC_MASK 0xc0
+
+/* ALC register */
+#define F81604_SJA1000_ALC_MASK 0x1f
+
+/* table of devices that work with this driver */
+static const struct usb_device_id f81604_table[] = {
+	{ USB_DEVICE(F81604_VENDOR_ID, F81604_PRODUCT_ID) },
+	{} /* Terminating entry */
+};
+
+MODULE_DEVICE_TABLE(usb, f81604_table);
+
+static const struct ethtool_ops f81604_ethtool_ops = {
+	.get_ts_info = ethtool_op_get_ts_info,
+};
+
+static const u16 f81604_termination[] = { F81604_TERMINATION_DISABLED,
+					  F81604_TERMINATION_ENABLED };
+
+struct f81604_priv {
+	struct net_device *netdev[F81604_MAX_DEV];
+};
+
+struct f81604_port_priv {
+	struct can_priv can;
+	struct net_device *netdev;
+	struct sk_buff *echo_skb;
+
+	unsigned long clear_flags;
+	struct work_struct clear_reg_work;
+
+	struct usb_device *dev;
+	struct usb_interface *intf;
+
+	struct usb_anchor urbs_anchor;
+};
+
+/* Interrupt endpoint data format:
+ *	Byte 0: Status register.
+ *	Byte 1: Interrupt register.
+ *	Byte 2: Interrupt enable register.
+ *	Byte 3: Arbitration lost capture(ALC) register.
+ *	Byte 4: Error code capture(ECC) register.
+ *	Byte 5: Error warning limit register.
+ *	Byte 6: RX error counter register.
+ *	Byte 7: TX error counter register.
+ *	Byte 8: Reserved.
+ */
+struct f81604_int_data {
+	u8 sr;
+	u8 isrc;
+	u8 ier;
+	u8 alc;
+	u8 ecc;
+	u8 ewlr;
+	u8 rxerr;
+	u8 txerr;
+	u8 val;
+} __packed __aligned(4);
+
+struct f81604_sff {
+	__be16 id;
+	u8 data[CAN_MAX_DLEN];
+} __packed __aligned(2);
+
+struct f81604_eff {
+	__be32 id;
+	u8 data[CAN_MAX_DLEN];
+} __packed __aligned(2);
+
+struct f81604_can_frame {
+	u8 cmd;
+
+	/* According for F81604 DLC define:
+	 *	bit 3~0: data length (0~8)
+	 *	bit6: is RTR flag.
+	 *	bit7: is EFF frame.
+	 */
+	u8 dlc;
+
+	union {
+		struct f81604_sff sff;
+		struct f81604_eff eff;
+	};
+} __packed __aligned(2);
+
+static const u8 bulk_in_addr[F81604_MAX_DEV] = { 2, 4 };
+static const u8 bulk_out_addr[F81604_MAX_DEV] = { 1, 3 };
+static const u8 int_in_addr[F81604_MAX_DEV] = { 1, 3 };
+
+static int f81604_write(struct usb_device *dev, u16 reg, u8 data)
+{
+	int ret;
+
+	ret = usb_control_msg_send(dev, 0, F81604_SET_GET_REGISTER,
+				   USB_TYPE_VENDOR | USB_DIR_OUT, 0, reg,
+				   &data, sizeof(data), F81604_USB_TIMEOUT,
+				   GFP_KERNEL);
+	if (ret)
+		dev_err(&dev->dev, "%s: reg: %x data: %x failed: %pe\n",
+			__func__, reg, data, ERR_PTR(ret));
+
+	return ret;
+}
+
+static int f81604_read(struct usb_device *dev, u16 reg, u8 *data)
+{
+	int ret;
+
+	ret = usb_control_msg_recv(dev, 0, F81604_SET_GET_REGISTER,
+				   USB_TYPE_VENDOR | USB_DIR_IN, 0, reg, data,
+				   sizeof(*data), F81604_USB_TIMEOUT,
+				   GFP_KERNEL);
+
+	if (ret < 0)
+		dev_err(&dev->dev, "%s: reg: %x failed: %pe\n", __func__, reg,
+			ERR_PTR(ret));
+
+	return ret;
+}
+
+static int f81604_update_bits(struct usb_device *dev, u16 reg, u8 mask,
+			      u8 data)
+{
+	int ret;
+	u8 tmp;
+
+	ret = f81604_read(dev, reg, &tmp);
+	if (ret)
+		return ret;
+
+	tmp &= ~mask;
+	tmp |= (mask & data);
+
+	return f81604_write(dev, reg, tmp);
+}
+
+static int f81604_sja1000_write(struct f81604_port_priv *priv, u16 reg,
+				u8 data)
+{
+	int port = priv->netdev->dev_port;
+	int real_reg;
+
+	real_reg = reg + F81604_PORT_OFFSET * port + F81604_PORT_OFFSET;
+	return f81604_write(priv->dev, real_reg, data);
+}
+
+static int f81604_sja1000_read(struct f81604_port_priv *priv, u16 reg,
+			       u8 *data)
+{
+	int port = priv->netdev->dev_port;
+	int real_reg;
+
+	real_reg = reg + F81604_PORT_OFFSET * port + F81604_PORT_OFFSET;
+	return f81604_read(priv->dev, real_reg, data);
+}
+
+static int f81604_set_reset_mode(struct f81604_port_priv *priv)
+{
+	int ret, i;
+	u8 tmp;
+
+	/* disable interrupts */
+	ret = f81604_sja1000_write(priv, F81604_SJA1000_IER,
+				   F81604_SJA1000_IRQ_OFF);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < F81604_SET_DEVICE_RETRY; i++) {
+		ret = f81604_sja1000_read(priv, F81604_SJA1000_MOD, &tmp);
+		if (ret)
+			return ret;
+
+		/* check reset bit */
+		if (tmp & F81604_SJA1000_MOD_RM) {
+			priv->can.state = CAN_STATE_STOPPED;
+			return 0;
+		}
+
+		/* reset chip */
+		ret = f81604_sja1000_write(priv, F81604_SJA1000_MOD,
+					   F81604_SJA1000_MOD_RM);
+		if (ret)
+			return ret;
+	}
+
+	return -EPERM;
+}
+
+static int f81604_set_normal_mode(struct f81604_port_priv *priv)
+{
+	u8 tmp, ier = 0;
+	u8 mod_reg = 0;
+	int ret, i;
+
+	for (i = 0; i < F81604_SET_DEVICE_RETRY; i++) {
+		ret = f81604_sja1000_read(priv, F81604_SJA1000_MOD, &tmp);
+		if (ret)
+			return ret;
+
+		/* check reset bit */
+		if ((tmp & F81604_SJA1000_MOD_RM) == 0) {
+			priv->can.state = CAN_STATE_ERROR_ACTIVE;
+			/* enable interrupts, RI handled by bulk-in */
+			ier = F81604_SJA1000_IRQ_ALL & ~F81604_SJA1000_IRQ_RI;
+			if (!(priv->can.ctrlmode &
+			      CAN_CTRLMODE_BERR_REPORTING))
+				ier &= ~F81604_SJA1000_IRQ_BEI;
+
+			return f81604_sja1000_write(priv, F81604_SJA1000_IER,
+						    ier);
+		}
+
+		/* set chip to normal mode */
+		if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
+			mod_reg |= F81604_SJA1000_MOD_LOM;
+		if (priv->can.ctrlmode & CAN_CTRLMODE_PRESUME_ACK)
+			mod_reg |= F81604_SJA1000_MOD_STM;
+
+		ret = f81604_sja1000_write(priv, F81604_SJA1000_MOD, mod_reg);
+		if (ret)
+			return ret;
+	}
+
+	return -EPERM;
+}
+
+static int f81604_chipset_init(struct f81604_port_priv *priv)
+{
+	int i, ret;
+
+	/* set clock divider and output control register */
+	ret = f81604_sja1000_write(priv, F81604_SJA1000_CDR,
+				   CDR_CBP | CDR_PELICAN);
+	if (ret)
+		return ret;
+
+	/* set acceptance filter (accept all) */
+	for (i = 0; i < F81604_MAX_FILTER_CNT; ++i) {
+		ret = f81604_sja1000_write(priv, F81604_SJA1000_ACCC0 + i, 0);
+		if (ret)
+			return ret;
+	}
+
+	for (i = 0; i < F81604_MAX_FILTER_CNT; ++i) {
+		ret = f81604_sja1000_write(priv, F81604_SJA1000_ACCM0 + i,
+					   0xFF);
+		if (ret)
+			return ret;
+	}
+
+	return f81604_sja1000_write(priv, F81604_SJA1000_OCR,
+				    OCR_TX0_PUSHPULL | OCR_TX1_PUSHPULL |
+					    OCR_MODE_NORMAL);
+}
+
+static void f81604_process_rx_packet(struct net_device *netdev,
+				     struct f81604_can_frame *frame)
+{
+	struct net_device_stats *stats = &netdev->stats;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+
+	if (frame->cmd != F81604_CMD_DATA)
+		return;
+
+	skb = alloc_can_skb(netdev, &cf);
+	if (!skb) {
+		stats->rx_dropped++;
+		return;
+	}
+
+	cf->len = can_cc_dlc2len(frame->dlc & F81604_DLC_LEN_MASK);
+
+	if (frame->dlc & F81604_DLC_EFF_BIT) {
+		cf->can_id = get_unaligned_be32(&frame->eff.id) >>
+			     F81604_EFF_SHIFT;
+		cf->can_id |= CAN_EFF_FLAG;
+
+		if (!(frame->dlc & F81604_DLC_RTR_BIT))
+			memcpy(cf->data, frame->eff.data, cf->len);
+	} else {
+		cf->can_id = get_unaligned_be16(&frame->sff.id) >>
+			     F81604_SFF_SHIFT;
+
+		if (!(frame->dlc & F81604_DLC_RTR_BIT))
+			memcpy(cf->data, frame->sff.data, cf->len);
+	}
+
+	if (frame->dlc & F81604_DLC_RTR_BIT)
+		cf->can_id |= CAN_RTR_FLAG;
+	else
+		stats->rx_bytes += cf->len;
+
+	stats->rx_packets++;
+	netif_rx(skb);
+}
+
+static void f81604_read_bulk_callback(struct urb *urb)
+{
+	struct f81604_can_frame *frame = urb->transfer_buffer;
+	struct net_device *netdev = urb->context;
+	int ret;
+
+	if (!netif_device_present(netdev))
+		return;
+
+	if (urb->status)
+		netdev_info(netdev, "%s: URB aborted %pe\n", __func__,
+			    ERR_PTR(urb->status));
+
+	switch (urb->status) {
+	case 0: /* success */
+		break;
+
+	case -ENOENT:
+	case -EPIPE:
+	case -EPROTO:
+	case -ESHUTDOWN:
+		return;
+
+	default:
+		goto resubmit_urb;
+	}
+
+	if (urb->actual_length != sizeof(*frame)) {
+		netdev_warn(netdev, "URB length %u not equal to %lu\n",
+			    urb->actual_length, sizeof(*frame));
+		goto resubmit_urb;
+	}
+
+	f81604_process_rx_packet(netdev, frame);
+
+resubmit_urb:
+	ret = usb_submit_urb(urb, GFP_ATOMIC);
+	if (ret == -ENODEV)
+		netif_device_detach(netdev);
+	else if (ret)
+		netdev_err(netdev,
+			   "%s: failed to resubmit read bulk urb: %pe\n",
+			   __func__, ERR_PTR(ret));
+}
+
+static void f81604_handle_tx(struct f81604_port_priv *priv,
+			     struct f81604_int_data *data)
+{
+	struct net_device *netdev = priv->netdev;
+	struct net_device_stats *stats = &netdev->stats;
+
+	/* transmission buffer released */
+	if (priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT &&
+	    !(data->sr & F81604_SJA1000_SR_TCS)) {
+		stats->tx_errors++;
+		can_free_echo_skb(netdev, 0, NULL);
+	} else {
+		/* transmission complete */
+		stats->tx_bytes += can_get_echo_skb(netdev, 0, NULL);
+		stats->tx_packets++;
+	}
+
+	netif_wake_queue(netdev);
+}
+
+static void f81604_handle_can_bus_errors(struct f81604_port_priv *priv,
+					 struct f81604_int_data *data)
+{
+	enum can_state can_state = priv->can.state;
+	struct net_device *netdev = priv->netdev;
+	struct net_device_stats *stats = &netdev->stats;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+
+	/* Note: ALC/ECC will not auto clear by read here, must be cleared by
+	 * read register (via clear_reg_work).
+	 */
+
+	skb = alloc_can_err_skb(netdev, &cf);
+	if (skb) {
+		cf->can_id |= CAN_ERR_CNT;
+		cf->data[6] = data->txerr;
+		cf->data[7] = data->rxerr;
+	}
+
+	if (data->isrc & F81604_SJA1000_IRQ_DOI) {
+		/* data overrun interrupt */
+		netdev_dbg(netdev, "data overrun interrupt\n");
+
+		if (skb) {
+			cf->can_id |= CAN_ERR_CRTL;
+			cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+		}
+
+		stats->rx_over_errors++;
+		stats->rx_errors++;
+
+		set_bit(F81604_CLEAR_OVERRUN, &priv->clear_flags);
+	}
+
+	if (data->isrc & F81604_SJA1000_IRQ_EI) {
+		/* error warning interrupt */
+		netdev_dbg(netdev, "error warning interrupt\n");
+
+		if (data->sr & F81604_SJA1000_SR_BS)
+			can_state = CAN_STATE_BUS_OFF;
+		else if (data->sr & F81604_SJA1000_SR_ES)
+			can_state = CAN_STATE_ERROR_WARNING;
+		else
+			can_state = CAN_STATE_ERROR_ACTIVE;
+	}
+
+	if (data->isrc & F81604_SJA1000_IRQ_BEI) {
+		/* bus error interrupt */
+		netdev_dbg(netdev, "bus error interrupt\n");
+
+		priv->can.can_stats.bus_error++;
+		stats->rx_errors++;
+
+		if (skb) {
+			cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+
+			/* set error type */
+			switch (data->ecc & F81604_SJA1000_ECC_MASK) {
+			case F81604_SJA1000_ECC_BIT:
+				cf->data[2] |= CAN_ERR_PROT_BIT;
+				break;
+			case F81604_SJA1000_ECC_FORM:
+				cf->data[2] |= CAN_ERR_PROT_FORM;
+				break;
+			case F81604_SJA1000_ECC_STUFF:
+				cf->data[2] |= CAN_ERR_PROT_STUFF;
+				break;
+			default:
+				break;
+			}
+
+			/* set error location */
+			cf->data[3] = data->ecc & F81604_SJA1000_ECC_SEG;
+
+			/* Error occurred during transmission? */
+			if ((data->ecc & F81604_SJA1000_ECC_DIR) == 0)
+				cf->data[2] |= CAN_ERR_PROT_TX;
+		}
+
+		set_bit(F81604_CLEAR_ECC, &priv->clear_flags);
+	}
+
+	if (data->isrc & F81604_SJA1000_IRQ_EPI) {
+		if (can_state == CAN_STATE_ERROR_PASSIVE)
+			can_state = CAN_STATE_ERROR_WARNING;
+		else
+			can_state = CAN_STATE_ERROR_PASSIVE;
+
+		/* error passive interrupt */
+		netdev_dbg(netdev, "error passive interrupt: %d\n", can_state);
+	}
+
+	if (data->isrc & F81604_SJA1000_IRQ_ALI) {
+		/* arbitration lost interrupt */
+		netdev_dbg(netdev, "arbitration lost interrupt\n");
+
+		priv->can.can_stats.arbitration_lost++;
+
+		if (skb) {
+			cf->can_id |= CAN_ERR_LOSTARB;
+			cf->data[0] = data->alc & F81604_SJA1000_ALC_MASK;
+		}
+
+		set_bit(F81604_CLEAR_ALC, &priv->clear_flags);
+	}
+
+	if (can_state != priv->can.state) {
+		enum can_state tx_state, rx_state;
+
+		tx_state = data->txerr >= data->rxerr ? can_state : 0;
+		rx_state = data->txerr <= data->rxerr ? can_state : 0;
+
+		can_change_state(netdev, cf, tx_state, rx_state);
+
+		if (can_state == CAN_STATE_BUS_OFF)
+			can_bus_off(netdev);
+	}
+
+	if (priv->clear_flags)
+		schedule_work(&priv->clear_reg_work);
+
+	if (skb)
+		netif_rx(skb);
+}
+
+static void f81604_read_int_callback(struct urb *urb)
+{
+	struct f81604_int_data *data = urb->transfer_buffer;
+	struct net_device *netdev = urb->context;
+	struct f81604_port_priv *priv;
+	int ret;
+
+	priv = netdev_priv(netdev);
+
+	if (!netif_device_present(netdev))
+		return;
+
+	if (urb->status)
+		netdev_info(netdev, "%s: Int URB aborted: %pe\n", __func__,
+			    ERR_PTR(urb->status));
+
+	switch (urb->status) {
+	case 0: /* success */
+		break;
+
+	case -ENOENT:
+	case -EPIPE:
+	case -EPROTO:
+	case -ESHUTDOWN:
+		return;
+
+	default:
+		goto resubmit_urb;
+	}
+
+	/* handle Errors */
+	if (data->isrc & (F81604_SJA1000_IRQ_DOI | F81604_SJA1000_IRQ_EI |
+			  F81604_SJA1000_IRQ_BEI | F81604_SJA1000_IRQ_EPI |
+			  F81604_SJA1000_IRQ_ALI))
+		f81604_handle_can_bus_errors(priv, data);
+
+	/* handle TX */
+	if (priv->can.state != CAN_STATE_BUS_OFF &&
+	    (data->isrc & F81604_SJA1000_IRQ_TI))
+		f81604_handle_tx(priv, data);
+
+resubmit_urb:
+	ret = usb_submit_urb(urb, GFP_ATOMIC);
+	if (ret == -ENODEV)
+		netif_device_detach(netdev);
+	else if (ret)
+		netdev_err(netdev, "%s: failed to resubmit int urb: %pe\n",
+			   __func__, ERR_PTR(ret));
+}
+
+static void f81604_unregister_urbs(struct f81604_port_priv *priv)
+{
+	usb_kill_anchored_urbs(&priv->urbs_anchor);
+}
+
+static int f81604_register_urbs(struct f81604_port_priv *priv)
+{
+	struct net_device *netdev = priv->netdev;
+	struct f81604_int_data *int_data;
+	int id = netdev->dev_port;
+	struct urb *int_urb;
+	int rx_urb_cnt;
+	int ret;
+
+	for (rx_urb_cnt = 0; rx_urb_cnt < F81604_MAX_RX_URBS; ++rx_urb_cnt) {
+		struct f81604_can_frame *frame;
+		struct urb *rx_urb;
+
+		rx_urb = usb_alloc_urb(0, GFP_KERNEL);
+		if (!rx_urb) {
+			ret = -ENOMEM;
+			break;
+		}
+
+		frame = kmalloc(sizeof(*frame), GFP_KERNEL);
+		if (!frame) {
+			usb_free_urb(rx_urb);
+			ret = -ENOMEM;
+			break;
+		}
+
+		usb_fill_bulk_urb(rx_urb, priv->dev,
+				  usb_rcvbulkpipe(priv->dev, bulk_in_addr[id]),
+				  frame, sizeof(*frame),
+				  f81604_read_bulk_callback, netdev);
+
+		rx_urb->transfer_flags |= URB_FREE_BUFFER;
+		usb_anchor_urb(rx_urb, &priv->urbs_anchor);
+
+		ret = usb_submit_urb(rx_urb, GFP_KERNEL);
+		if (ret) {
+			usb_unanchor_urb(rx_urb);
+			usb_free_urb(rx_urb);
+			break;
+		}
+
+		/* Drop reference, USB core will take care of freeing it */
+		usb_free_urb(rx_urb);
+	}
+
+	if (rx_urb_cnt == 0) {
+		netdev_warn(netdev, "%s: submit rx urb failed: %pe\n",
+			    __func__, ERR_PTR(ret));
+
+		goto error;
+	}
+
+	int_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!int_urb) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	int_data = kmalloc(sizeof(*int_data), GFP_KERNEL);
+	if (!int_data) {
+		usb_free_urb(int_urb);
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	usb_fill_int_urb(int_urb, priv->dev,
+			 usb_rcvintpipe(priv->dev, int_in_addr[id]), int_data,
+			 sizeof(*int_data), f81604_read_int_callback, netdev,
+			 1);
+
+	int_urb->transfer_flags |= URB_FREE_BUFFER;
+	usb_anchor_urb(int_urb, &priv->urbs_anchor);
+
+	ret = usb_submit_urb(int_urb, GFP_KERNEL);
+	if (ret) {
+		usb_unanchor_urb(int_urb);
+		usb_free_urb(int_urb);
+
+		netdev_warn(netdev, "%s: submit int urb failed: %pe\n",
+			    __func__, ERR_PTR(ret));
+		goto error;
+	}
+
+	/* Drop reference, USB core will take care of freeing it */
+	usb_free_urb(int_urb);
+
+	return 0;
+
+error:
+	f81604_unregister_urbs(priv);
+	return ret;
+}
+
+static int f81604_start(struct net_device *netdev)
+{
+	struct f81604_port_priv *priv = netdev_priv(netdev);
+	int ret;
+	u8 mode;
+	u8 tmp;
+
+	mode = F81604_RX_AUTO_RELEASE_BUF | F81604_INT_WHEN_CHANGE;
+
+	/* Set TR/AT mode */
+	if (priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT)
+		mode |= F81604_TX_ONESHOT;
+	else
+		mode |= F81604_TX_NORMAL;
+
+	ret = f81604_sja1000_write(priv, F81604_CTRL_MODE_REG, mode);
+	if (ret)
+		return ret;
+
+	/* set reset mode */
+	ret = f81604_set_reset_mode(priv);
+	if (ret)
+		return ret;
+
+	ret = f81604_chipset_init(priv);
+	if (ret)
+		return ret;
+
+	/* Clear error counters and error code capture */
+	ret = f81604_sja1000_write(priv, F81604_SJA1000_TXERR, 0);
+	if (ret)
+		return ret;
+
+	ret = f81604_sja1000_write(priv, F81604_SJA1000_RXERR, 0);
+	if (ret)
+		return ret;
+
+	/* Read clear for ECC/ALC/IR register */
+	ret = f81604_sja1000_read(priv, F81604_SJA1000_ECC, &tmp);
+	if (ret)
+		return ret;
+
+	ret = f81604_sja1000_read(priv, F81604_SJA1000_ALC, &tmp);
+	if (ret)
+		return ret;
+
+	ret = f81604_sja1000_read(priv, F81604_SJA1000_IR, &tmp);
+	if (ret)
+		return ret;
+
+	ret = f81604_register_urbs(priv);
+	if (ret)
+		return ret;
+
+	ret = f81604_set_normal_mode(priv);
+	if (ret) {
+		f81604_unregister_urbs(priv);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int f81604_set_bittiming(struct net_device *dev)
+{
+	struct f81604_port_priv *priv = netdev_priv(dev);
+	struct can_bittiming *bt = &priv->can.bittiming;
+	u8 btr0, btr1;
+	int ret;
+
+	btr0 = FIELD_PREP(F81604_BRP_MASK, bt->brp - 1) |
+	       FIELD_PREP(F81604_SJW_MASK, bt->sjw - 1);
+
+	btr1 = FIELD_PREP(F81604_SEG1_MASK,
+			  bt->prop_seg + bt->phase_seg1 - 1) |
+	       FIELD_PREP(F81604_SEG2_MASK, bt->phase_seg2 - 1);
+
+	if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
+		btr1 |= F81604_SJA1000_BTR1_SAMPLE_TRIPLE;
+
+	ret = f81604_sja1000_write(priv, F81604_SJA1000_BTR0, btr0);
+	if (ret) {
+		netdev_warn(dev, "%s: Set BTR0 failed: %pe\n", __func__,
+			    ERR_PTR(ret));
+		return ret;
+	}
+
+	ret = f81604_sja1000_write(priv, F81604_SJA1000_BTR1, btr1);
+	if (ret) {
+		netdev_warn(dev, "%s: Set BTR1 failed: %pe\n", __func__,
+			    ERR_PTR(ret));
+		return ret;
+	}
+
+	return 0;
+}
+
+static int f81604_set_mode(struct net_device *netdev, enum can_mode mode)
+{
+	int ret;
+
+	switch (mode) {
+	case CAN_MODE_START:
+		ret = f81604_start(netdev);
+		if (!ret && netif_queue_stopped(netdev))
+			netif_wake_queue(netdev);
+		break;
+
+	default:
+		ret = -EOPNOTSUPP;
+	}
+
+	return ret;
+}
+
+static void f81604_write_bulk_callback(struct urb *urb)
+{
+	struct net_device *netdev = urb->context;
+
+	if (!netif_device_present(netdev))
+		return;
+
+	if (urb->status)
+		netdev_info(netdev, "%s: Tx URB error: %pe\n", __func__,
+			    ERR_PTR(urb->status));
+}
+
+static void f81604_clear_reg_work(struct work_struct *work)
+{
+	struct f81604_port_priv *priv;
+	u8 tmp;
+
+	priv = container_of(work, struct f81604_port_priv, clear_reg_work);
+
+	/* dummy read for clear Arbitration lost capture(ALC) register. */
+	if (test_and_clear_bit(F81604_CLEAR_ALC, &priv->clear_flags))
+		f81604_sja1000_read(priv, F81604_SJA1000_ALC, &tmp);
+
+	/* dummy read for clear Error code capture(ECC) register. */
+	if (test_and_clear_bit(F81604_CLEAR_ECC, &priv->clear_flags))
+		f81604_sja1000_read(priv, F81604_SJA1000_ECC, &tmp);
+
+	/* dummy write for clear data overrun flag. */
+	if (test_and_clear_bit(F81604_CLEAR_OVERRUN, &priv->clear_flags))
+		f81604_sja1000_write(priv, F81604_SJA1000_CMR,
+				     F81604_SJA1000_CMD_CDO);
+}
+
+static netdev_tx_t f81604_start_xmit(struct sk_buff *skb,
+				     struct net_device *netdev)
+{
+	struct can_frame *cf = (struct can_frame *)skb->data;
+	struct f81604_port_priv *priv = netdev_priv(netdev);
+	struct net_device_stats *stats = &netdev->stats;
+	struct f81604_can_frame *frame;
+	struct urb *write_urb;
+	int ret;
+
+	if (can_dev_dropped_skb(netdev, skb))
+		return NETDEV_TX_OK;
+
+	netif_stop_queue(netdev);
+
+	write_urb = usb_alloc_urb(0, GFP_ATOMIC);
+	if (!write_urb)
+		goto nomem_urb;
+
+	frame = kzalloc(sizeof(*frame), GFP_ATOMIC);
+	if (!frame)
+		goto nomem_buf;
+
+	usb_fill_bulk_urb(write_urb, priv->dev,
+			  usb_sndbulkpipe(priv->dev,
+					  bulk_out_addr[netdev->dev_port]),
+			  frame, sizeof(*frame), f81604_write_bulk_callback,
+			  priv->netdev);
+
+	write_urb->transfer_flags |= URB_FREE_BUFFER;
+
+	frame->cmd = F81604_CMD_DATA;
+	frame->dlc = cf->len;
+
+	if (cf->can_id & CAN_RTR_FLAG)
+		frame->dlc |= F81604_DLC_RTR_BIT;
+
+	if (cf->can_id & CAN_EFF_FLAG) {
+		u32 id = (cf->can_id & CAN_EFF_MASK) << F81604_EFF_SHIFT;
+
+		put_unaligned_be32(id, &frame->eff.id);
+
+		frame->dlc |= F81604_DLC_EFF_BIT;
+
+		if (!(cf->can_id & CAN_RTR_FLAG))
+			memcpy(&frame->eff.data, cf->data, cf->len);
+	} else {
+		u32 id = (cf->can_id & CAN_SFF_MASK) << F81604_SFF_SHIFT;
+
+		put_unaligned_be16(id, &frame->sff.id);
+
+		if (!(cf->can_id & CAN_RTR_FLAG))
+			memcpy(&frame->sff.data, cf->data, cf->len);
+	}
+
+	can_put_echo_skb(skb, netdev, 0, 0);
+
+	ret = usb_submit_urb(write_urb, GFP_ATOMIC);
+	if (ret) {
+		netdev_err(netdev, "%s: failed to resubmit tx bulk urb: %pe\n",
+			   __func__, ERR_PTR(ret));
+
+		can_free_echo_skb(netdev, 0, NULL);
+		stats->tx_dropped++;
+		stats->tx_errors++;
+
+		if (ret == -ENODEV)
+			netif_device_detach(netdev);
+		else
+			netif_wake_queue(netdev);
+	}
+
+	/* let usb core take care of this urb */
+	usb_free_urb(write_urb);
+
+	return NETDEV_TX_OK;
+
+nomem_buf:
+	usb_free_urb(write_urb);
+
+nomem_urb:
+	dev_kfree_skb(skb);
+	stats->tx_dropped++;
+	stats->tx_errors++;
+	netif_wake_queue(netdev);
+
+	return NETDEV_TX_OK;
+}
+
+static int f81604_get_berr_counter(const struct net_device *netdev,
+				   struct can_berr_counter *bec)
+{
+	struct f81604_port_priv *priv = netdev_priv(netdev);
+	u8 txerr, rxerr;
+	int ret;
+
+	ret = f81604_sja1000_read(priv, F81604_SJA1000_TXERR, &txerr);
+	if (ret)
+		return ret;
+
+	ret = f81604_sja1000_read(priv, F81604_SJA1000_RXERR, &rxerr);
+	if (ret)
+		return ret;
+
+	bec->txerr = txerr;
+	bec->rxerr = rxerr;
+
+	return 0;
+}
+
+/* Open USB device */
+static int f81604_open(struct net_device *netdev)
+{
+	int ret;
+
+	ret = open_candev(netdev);
+	if (ret)
+		return ret;
+
+	ret = f81604_start(netdev);
+	if (ret) {
+		if (ret == -ENODEV)
+			netif_device_detach(netdev);
+
+		close_candev(netdev);
+		return ret;
+	}
+
+	netif_start_queue(netdev);
+	return 0;
+}
+
+/* Close USB device */
+static int f81604_close(struct net_device *netdev)
+{
+	struct f81604_port_priv *priv = netdev_priv(netdev);
+
+	f81604_set_reset_mode(priv);
+
+	netif_stop_queue(netdev);
+	cancel_work_sync(&priv->clear_reg_work);
+	close_candev(netdev);
+
+	f81604_unregister_urbs(priv);
+
+	return 0;
+}
+
+static const struct net_device_ops f81604_netdev_ops = {
+	.ndo_open = f81604_open,
+	.ndo_stop = f81604_close,
+	.ndo_start_xmit = f81604_start_xmit,
+	.ndo_change_mtu = can_change_mtu,
+};
+
+static const struct can_bittiming_const f81604_bittiming_const = {
+	.name = KBUILD_MODNAME,
+	.tseg1_min = 1,
+	.tseg1_max = 16,
+	.tseg2_min = 1,
+	.tseg2_max = 8,
+	.sjw_max = 4,
+	.brp_min = 1,
+	.brp_max = 64,
+	.brp_inc = 1,
+};
+
+/* Called by the usb core when driver is unloaded or device is removed */
+static void f81604_disconnect(struct usb_interface *intf)
+{
+	struct f81604_priv *priv = usb_get_intfdata(intf);
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(priv->netdev); ++i) {
+		if (!priv->netdev[i])
+			continue;
+
+		unregister_netdev(priv->netdev[i]);
+		free_candev(priv->netdev[i]);
+	}
+}
+
+static int __f81604_set_termination(struct usb_device *dev, int idx, u16 term)
+{
+	u8 mask, data = 0;
+
+	if (idx == 0)
+		mask = F81604_CAN0_TERM;
+	else
+		mask = F81604_CAN1_TERM;
+
+	if (term)
+		data = mask;
+
+	return f81604_update_bits(dev, F81604_TERMINATOR_REG, mask, data);
+}
+
+static int f81604_set_termination(struct net_device *netdev, u16 term)
+{
+	struct f81604_port_priv *port_priv = netdev_priv(netdev);
+
+	ASSERT_RTNL();
+
+	return __f81604_set_termination(port_priv->dev, netdev->dev_port,
+					term);
+}
+
+static int f81604_probe(struct usb_interface *intf,
+			const struct usb_device_id *id)
+{
+	struct usb_device *dev = interface_to_usbdev(intf);
+	struct net_device *netdev;
+	struct f81604_priv *priv;
+	int i, ret;
+
+	priv = devm_kzalloc(&intf->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	usb_set_intfdata(intf, priv);
+
+	for (i = 0; i < ARRAY_SIZE(priv->netdev); ++i) {
+		ret = __f81604_set_termination(dev, i, 0);
+		if (ret) {
+			dev_err(&intf->dev,
+				"Setting termination of CH#%d failed: %pe\n",
+				i, ERR_PTR(ret));
+			return ret;
+		}
+	}
+
+	for (i = 0; i < ARRAY_SIZE(priv->netdev); ++i) {
+		struct f81604_port_priv *port_priv;
+
+		netdev = alloc_candev(sizeof(*port_priv), 1);
+		if (!netdev) {
+			dev_err(&intf->dev, "Couldn't alloc candev: %d\n", i);
+			ret = -ENOMEM;
+
+			goto failure_cleanup;
+		}
+
+		port_priv = netdev_priv(netdev);
+
+		INIT_WORK(&port_priv->clear_reg_work, f81604_clear_reg_work);
+		init_usb_anchor(&port_priv->urbs_anchor);
+
+		port_priv->intf = intf;
+		port_priv->dev = dev;
+		port_priv->netdev = netdev;
+		port_priv->can.clock.freq = F81604_CAN_CLOCK;
+
+		port_priv->can.termination_const = f81604_termination;
+		port_priv->can.termination_const_cnt =
+			ARRAY_SIZE(f81604_termination);
+		port_priv->can.bittiming_const = &f81604_bittiming_const;
+		port_priv->can.do_set_bittiming = f81604_set_bittiming;
+		port_priv->can.do_set_mode = f81604_set_mode;
+		port_priv->can.do_set_termination = f81604_set_termination;
+		port_priv->can.do_get_berr_counter = f81604_get_berr_counter;
+		port_priv->can.ctrlmode_supported =
+			CAN_CTRLMODE_LISTENONLY | CAN_CTRLMODE_3_SAMPLES |
+			CAN_CTRLMODE_ONE_SHOT | CAN_CTRLMODE_BERR_REPORTING |
+			CAN_CTRLMODE_PRESUME_ACK;
+
+		netdev->ethtool_ops = &f81604_ethtool_ops;
+		netdev->netdev_ops = &f81604_netdev_ops;
+		netdev->flags |= IFF_ECHO;
+		netdev->dev_port = i;
+
+		SET_NETDEV_DEV(netdev, &intf->dev);
+
+		ret = register_candev(netdev);
+		if (ret) {
+			netdev_err(netdev, "register CAN device failed: %pe\n",
+				   ERR_PTR(ret));
+			free_candev(netdev);
+
+			goto failure_cleanup;
+		}
+
+		priv->netdev[i] = netdev;
+	}
+
+	return 0;
+
+failure_cleanup:
+	f81604_disconnect(intf);
+	return ret;
+}
+
+static struct usb_driver f81604_driver = {
+	.name = KBUILD_MODNAME,
+	.probe = f81604_probe,
+	.disconnect = f81604_disconnect,
+	.id_table = f81604_table,
+};
+
+module_usb_driver(f81604_driver);
+
+MODULE_AUTHOR("Ji-Ze Hong (Peter Hong) <peter_hong@fintek.com.tw>");
+MODULE_DESCRIPTION("Fintek F81604 USB to 2xCANBUS");
+MODULE_LICENSE("GPL");
-- 
2.17.1