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>
CC:     <davem@davemloft.net>, <edumazet@google.com>, <kuba@kernel.org>,
        <pabeni@redhat.com>, <mailhol.vincent@wanadoo.fr>,
        <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 V2] can: usb: f81604: add Fintek F81604 support
Date:   Tue, 21 Mar 2023 16:11:52 +0800
Message-ID: <20230321081152.26510-1-peter_hong@fintek.com.tw>
MIME-Version: 1.0
Content-Type: text/plain; charset="y"
Content-Transfer-Encoding: 8bit
Precedence: bulk

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

Signed-off-by: Ji-Ze Hong (Peter Hong) <peter_hong@fintek.com.tw>
---
Changelog:
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().

 drivers/net/can/usb/Kconfig  |    9 +
 drivers/net/can/usb/Makefile |    1 +
 drivers/net/can/usb/f81604.c | 1179 ++++++++++++++++++++++++++++++++++
 3 files changed, 1189 insertions(+)
 create mode 100644 drivers/net/can/usb/f81604.c

diff --git a/drivers/net/can/usb/Kconfig b/drivers/net/can/usb/Kconfig
index 445504ababce..381547939c39 100644
--- a/drivers/net/can/usb/Kconfig
+++ b/drivers/net/can/usb/Kconfig
@@ -147,4 +147,13 @@ config CAN_UCAN
 	          from Theobroma Systems like the A31-µQ7 and the RK3399-Q7
 	          (https://www.theobroma-systems.com/rk3399-q7)
 
+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).
+
+	  (see also https://www.fintek.com.tw).
+
 endmenu
diff --git a/drivers/net/can/usb/Makefile b/drivers/net/can/usb/Makefile
index 1ea16be5743b..9de0305a5cce 100644
--- a/drivers/net/can/usb/Makefile
+++ b/drivers/net/can/usb/Makefile
@@ -12,3 +12,4 @@ obj-$(CONFIG_CAN_KVASER_USB) += kvaser_usb/
 obj-$(CONFIG_CAN_MCBA_USB) += mcba_usb.o
 obj-$(CONFIG_CAN_PEAK_USB) += peak_usb/
 obj-$(CONFIG_CAN_UCAN) += ucan.o
+obj-$(CONFIG_CAN_F81604) += f81604.o
diff --git a/drivers/net/can/usb/f81604.c b/drivers/net/can/usb/f81604.c
new file mode 100644
index 000000000000..969c3f72a2b1
--- /dev/null
+++ b/drivers/net/can/usb/f81604.c
@@ -0,0 +1,1179 @@
+// 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/netdevice.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>
+
+/* vendor and product id */
+#define F81604_VENDOR_ID 0x2c42
+#define F81604_PRODUCT_ID 0x1709
+#define F81604_MAX_DEV 2
+#define F81604_MAX_DEVICE_RETRY 100
+
+#define F81604_USB_MAX_RETRY 10
+#define F81604_USB_TIMEOUT 2000
+#define F81604_SET_GET_REGISTER 0xA0
+#define F81604_PORT_OFFSET 0x1000
+
+#define F81604_BULK_SIZE 64
+#define F81604_INT_SIZE 16
+#define F81604_DATA_SIZE 14
+#define F81604_MAX_RX_URBS 4
+
+#define F81604_CMD_OFFSET 0x00
+#define F81604_CMD_DATA 0x00
+
+#define F81604_DLC_OFFSET 0x01
+#define F81604_LEN_MASK 0x0f
+#define F81604_EFF_BIT BIT(7)
+#define F81604_RTR_BIT BIT(6)
+
+#define F81604_ID1_OFFSET 0x02
+#define F81604_ID2_OFFSET 0x03
+#define F81604_ID3_OFFSET 0x04
+#define F81604_ID4_OFFSET 0x05
+
+#define F81604_SFF_DATA_OFFSET 0x04
+#define F81604_EFF_DATA_OFFSET 0x06
+
+/* device setting */
+#define F81604_TX_ONESHOT (0x03 << 3)
+#define F81604_TX_NORMAL (0x01 << 3)
+#define F81604_RX_AUTO_RELEASE_BUF (0x01 << 1)
+#define F81604_INT_WHEN_CHANGE (0x01 << 0)
+
+/* SJA1000 registers - manual section 6.4 (Pelican Mode) */
+#define SJA1000_MOD 0x00
+#define SJA1000_CMR 0x01
+#define SJA1000_IR 0x03
+#define SJA1000_IER 0x04
+#define SJA1000_ALC 0x0B
+#define SJA1000_ECC 0x0C
+#define SJA1000_RXERR 0x0E
+#define SJA1000_TXERR 0x0F
+#define SJA1000_ACCC0 0x10
+#define SJA1000_ACCC1 0x11
+#define SJA1000_ACCC2 0x12
+#define SJA1000_ACCC3 0x13
+#define SJA1000_ACCM0 0x14
+#define SJA1000_ACCM1 0x15
+#define SJA1000_ACCM2 0x16
+#define SJA1000_ACCM3 0x17
+#define SJA1000_MAX_FILTER_CNT 4
+
+/* Common registers - manual section 6.5 */
+#define SJA1000_BTR0 0x06
+#define SJA1000_BTR1 0x07
+#define SJA1000_OCR 0x08
+#define SJA1000_CDR 0x1F
+
+#define SJA1000_FI 0x10
+#define SJA1000_SFF_BUF 0x13
+#define SJA1000_EFF_BUF 0x15
+
+#define SJA1000_FI_FF 0x80
+#define SJA1000_FI_RTR 0x40
+
+#define SJA1000_ID1 0x11
+#define SJA1000_ID2 0x12
+#define SJA1000_ID3 0x13
+#define SJA1000_ID4 0x14
+
+/* mode register */
+#define MOD_RM 0x01
+#define MOD_LOM 0x02
+#define MOD_STM 0x04
+
+/* commands */
+#define CMD_CDO 0x08
+
+/* interrupt sources */
+#define IRQ_BEI 0x80
+#define IRQ_ALI 0x40
+#define IRQ_EPI 0x20
+#define IRQ_DOI 0x08
+#define IRQ_EI 0x04
+#define IRQ_TI 0x02
+#define IRQ_RI 0x01
+#define IRQ_ALL 0xFF
+#define IRQ_OFF 0x00
+
+/* status register content */
+#define SR_BS 0x80
+#define SR_ES 0x40
+#define SR_TS 0x20
+#define SR_RS 0x10
+#define SR_TCS 0x08
+#define SR_TBS 0x04
+#define SR_DOS 0x02
+#define SR_RBS 0x01
+
+/* ECC register */
+#define ECC_SEG 0x1F
+#define ECC_DIR 0x20
+#define ECC_BIT 0x00
+#define ECC_FORM 0x40
+#define ECC_STUFF 0x80
+#define ECC_MASK 0xc0
+
+/* 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);
+
+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;
+
+	/* For synchronize need_clear_alc/need_clear_ecc in worker & interrupt
+	 * callback.
+	 */
+	spinlock_t lock;
+	bool need_clear_alc;
+	bool need_clear_ecc;
+
+	struct work_struct handle_clear_reg_work;
+	struct work_struct handle_clear_overrun_work;
+
+	struct usb_device *dev;
+	struct usb_interface *intf;
+
+	struct urb *int_urb;
+	u8 int_read_buffer[F81604_INT_SIZE];
+
+	struct urb *read_urb[F81604_MAX_RX_URBS];
+	u8 bulk_read_buffer[F81604_MAX_RX_URBS][F81604_BULK_SIZE];
+
+	struct urb *write_urb;
+	u8 bulk_write_buffer[F81604_DATA_SIZE];
+
+	u8 ocr;
+	u8 cdr;
+};
+
+static int f81604_set_register(struct usb_device *dev, u16 reg, u8 data)
+{
+	size_t count = F81604_USB_MAX_RETRY;
+	int status;
+
+	while (count--) {
+		status = usb_control_msg_send(dev, 0, F81604_SET_GET_REGISTER,
+					      USB_TYPE_VENDOR | USB_DIR_OUT, 0,
+					      reg, &data, sizeof(u8),
+					      F81604_USB_TIMEOUT, GFP_KERNEL);
+		if (!status)
+			break;
+	}
+
+	if (status)
+		dev_err(&dev->dev, "%s: reg: %x data: %x failed: %d\n",
+			__func__, reg, data, status);
+
+	return status;
+}
+
+static int f81604_get_register(struct usb_device *dev, u16 reg, u8 *data)
+{
+	size_t count = F81604_USB_MAX_RETRY;
+	int status;
+
+	while (count--) {
+		status = usb_control_msg_recv(dev, 0, F81604_SET_GET_REGISTER,
+					      USB_TYPE_VENDOR | USB_DIR_IN, 0,
+					      reg, data, sizeof(u8),
+					      F81604_USB_TIMEOUT, GFP_KERNEL);
+		if (!status)
+			break;
+	}
+
+	if (status < 0)
+		dev_err(&dev->dev, "%s: reg: %x failed: %d\n", __func__, reg,
+			status);
+
+	return status;
+}
+
+static int f81604_set_sja1000_register(struct usb_device *dev, u8 port,
+				       u16 reg, u8 data)
+{
+	int real_reg;
+
+	real_reg = reg + F81604_PORT_OFFSET * port + F81604_PORT_OFFSET;
+	return f81604_set_register(dev, real_reg, data);
+}
+
+static int f81604_get_sja1000_register(struct usb_device *dev, u8 port,
+				       u16 reg, u8 *data)
+{
+	int real_reg;
+
+	real_reg = reg + F81604_PORT_OFFSET * port + F81604_PORT_OFFSET;
+	return f81604_get_register(dev, real_reg, data);
+}
+
+static int f81604_set_reset_mode(struct net_device *netdev)
+{
+	struct f81604_port_priv *priv = netdev_priv(netdev);
+	int status, i;
+	u8 tmp;
+
+	/* disable interrupts */
+	status = f81604_set_sja1000_register(priv->dev, netdev->dev_id,
+					     SJA1000_IER, IRQ_OFF);
+	if (status)
+		return status;
+
+	for (i = 0; i < F81604_MAX_DEVICE_RETRY; i++) {
+		status = f81604_get_sja1000_register(priv->dev, netdev->dev_id,
+						     SJA1000_MOD, &tmp);
+		if (status)
+			return status;
+
+		/* check reset bit */
+		if (tmp & MOD_RM) {
+			priv->can.state = CAN_STATE_STOPPED;
+			return 0;
+		}
+
+		/* reset chip */
+		status = f81604_set_sja1000_register(priv->dev, netdev->dev_id,
+						     SJA1000_MOD, MOD_RM);
+		if (status)
+			return status;
+	}
+
+	netdev_err(netdev, "setting SJA1000 into reset mode failed!\n");
+	return -EINVAL;
+}
+
+static int f81604_set_normal_mode(struct net_device *netdev)
+{
+	struct f81604_port_priv *priv = netdev_priv(netdev);
+	u8 mod_reg = 0x00;
+	u8 tmp, ier = 0;
+	int status, i;
+
+	for (i = 0; i < F81604_MAX_DEVICE_RETRY; i++) {
+		status = f81604_get_sja1000_register(priv->dev, netdev->dev_id,
+						     SJA1000_MOD, &tmp);
+		if (status)
+			return status;
+
+		/* check reset bit */
+		if ((tmp & MOD_RM) == 0) {
+			priv->can.state = CAN_STATE_ERROR_ACTIVE;
+			/* enable interrupts, RI handled by bulk-in */
+			if (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)
+				ier = IRQ_ALL & ~IRQ_RI;
+			else
+				ier = IRQ_ALL & ~(IRQ_RI | IRQ_BEI);
+
+			status = f81604_set_sja1000_register(priv->dev,
+							     netdev->dev_id,
+							     SJA1000_IER, ier);
+
+			return status;
+		}
+
+		/* set chip to normal mode */
+		if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
+			mod_reg |= MOD_LOM;
+		if (priv->can.ctrlmode & CAN_CTRLMODE_PRESUME_ACK)
+			mod_reg |= MOD_STM;
+
+		status = f81604_set_sja1000_register(priv->dev, netdev->dev_id,
+						     SJA1000_MOD, mod_reg);
+		if (status)
+			return status;
+	}
+
+	netdev_err(netdev, "setting SJA1000 into normal mode failed!\n");
+	return -EINVAL;
+}
+
+static int f81604_chipset_init(struct net_device *netdev)
+{
+	struct f81604_port_priv *priv = netdev_priv(netdev);
+	int status;
+	int i;
+
+	/* set clock divider and output control register */
+	status = f81604_set_sja1000_register(priv->dev, netdev->dev_id,
+					     SJA1000_CDR,
+					     priv->cdr | CDR_PELICAN);
+	if (status)
+		return status;
+
+	/* set acceptance filter (accept all) */
+	for (i = 0; i < SJA1000_MAX_FILTER_CNT; ++i) {
+		status = f81604_set_sja1000_register(priv->dev, netdev->dev_id,
+						     SJA1000_ACCC0 + i, 0);
+		if (status)
+			return status;
+	}
+
+	for (i = 0; i < SJA1000_MAX_FILTER_CNT; ++i) {
+		status = f81604_set_sja1000_register(priv->dev, netdev->dev_id,
+						     SJA1000_ACCM0 + i, 0xFF);
+		if (status)
+			return status;
+	}
+
+	return f81604_set_sja1000_register(priv->dev, netdev->dev_id,
+					   SJA1000_OCR,
+					   priv->ocr | OCR_MODE_NORMAL);
+}
+
+static void f81604_unregister_urbs(struct net_device *netdev)
+{
+	struct f81604_port_priv *priv = netdev_priv(netdev);
+	int i;
+
+	usb_kill_urb(priv->write_urb);
+
+	for (i = 0; i < F81604_MAX_RX_URBS; ++i)
+		usb_kill_urb(priv->read_urb[i]);
+
+	usb_kill_urb(priv->int_urb);
+}
+
+static int f81604_register_urbs(struct net_device *netdev)
+{
+	struct f81604_port_priv *priv = netdev_priv(netdev);
+	int status, i;
+
+	for (i = 0; i < F81604_MAX_RX_URBS; ++i) {
+		status = usb_submit_urb(priv->read_urb[i], GFP_KERNEL);
+		if (status) {
+			netdev_warn(netdev, "%s: submit rx urb failed: %d\n",
+				    __func__, status);
+			return status;
+		}
+	}
+
+	status = usb_submit_urb(priv->int_urb, GFP_KERNEL);
+	if (status) {
+		netdev_warn(netdev, "%s: submit int urb failed: %d\n",
+			    __func__, status);
+		return status;
+	}
+
+	return 0;
+}
+
+static int f81604_start(struct net_device *netdev)
+{
+	struct f81604_port_priv *priv = netdev_priv(netdev);
+	int status;
+	u8 mode;
+	u8 tmp;
+
+	f81604_unregister_urbs(netdev);
+
+	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;
+
+	status = f81604_set_sja1000_register(priv->dev, netdev->dev_id, 0x80,
+					     mode);
+	if (status)
+		return status;
+
+	/* set reset mode */
+	status = f81604_set_reset_mode(netdev);
+	if (status)
+		return status;
+
+	status = f81604_chipset_init(netdev);
+	if (status)
+		return status;
+
+	/* Clear error counters and error code capture */
+	status = f81604_set_sja1000_register(priv->dev, netdev->dev_id,
+					     SJA1000_TXERR, 0);
+	if (status)
+		return status;
+
+	status = f81604_set_sja1000_register(priv->dev, netdev->dev_id,
+					     SJA1000_RXERR, 0);
+	if (status)
+		return status;
+
+	/* Read clear for ECC/ALC/IR register */
+	status = f81604_get_sja1000_register(priv->dev, netdev->dev_id,
+					     SJA1000_ECC, &tmp);
+	if (status)
+		return status;
+
+	status = f81604_get_sja1000_register(priv->dev, netdev->dev_id,
+					     SJA1000_ALC, &tmp);
+	if (status)
+		return status;
+
+	status = f81604_get_sja1000_register(priv->dev, netdev->dev_id,
+					     SJA1000_IR, &tmp);
+	if (status)
+		return status;
+
+	status = f81604_register_urbs(netdev);
+	if (status)
+		return status;
+
+	return f81604_set_normal_mode(netdev);
+}
+
+static int f81604_set_bittiming(struct net_device *dev)
+{
+	struct f81604_port_priv *priv = netdev_priv(dev);
+	struct can_bittiming *bt = &priv->can.bittiming;
+	int status = 0;
+	u8 btr0, btr1;
+
+	btr0 = ((bt->brp - 1) & 0x3f) | (((bt->sjw - 1) & 0x3) << 6);
+	btr1 = ((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) |
+	       (((bt->phase_seg2 - 1) & 0x7) << 4);
+
+	if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
+		btr1 |= 0x80;
+
+	netdev_info(dev, "BTR0=0x%02x BTR1=0x%02x\n", btr0, btr1);
+
+	status = f81604_set_sja1000_register(priv->dev, dev->dev_id,
+					     SJA1000_BTR0, btr0);
+	if (status) {
+		netdev_warn(dev, "%s: Set BTR0 failed: %d\n", __func__,
+			    status);
+		return status;
+	}
+
+	status = f81604_set_sja1000_register(priv->dev, dev->dev_id,
+					     SJA1000_BTR1, btr1);
+	if (status) {
+		netdev_warn(dev, "%s: Set BTR1 failed: %d\n", __func__,
+			    status);
+		return status;
+	}
+
+	return 0;
+}
+
+static int f81604_set_mode(struct net_device *netdev, enum can_mode mode)
+{
+	int err;
+
+	switch (mode) {
+	case CAN_MODE_START:
+		err = f81604_start(netdev);
+		if (!err && netif_queue_stopped(netdev))
+			netif_wake_queue(netdev);
+		break;
+
+	default:
+		err = -EOPNOTSUPP;
+	}
+
+	return err;
+}
+
+static void f81604_process_rx_packet(struct urb *urb)
+{
+	struct net_device *netdev = urb->context;
+	struct net_device_stats *stats;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+	int i, count;
+	u8 *data;
+	u8 *ptr;
+
+	data = urb->transfer_buffer;
+	stats = &netdev->stats;
+
+	if (urb->actual_length % 14)
+		netdev_warn(netdev, "actual_length %% 14 != 0 (%d)\n",
+			    urb->actual_length);
+	else if (!urb->actual_length)
+		netdev_warn(netdev, "actual_length = 0 (%d)\n",
+			    urb->actual_length);
+
+	count = urb->actual_length / F81604_DATA_SIZE;
+
+	for (i = 0; i < count; ++i) {
+		ptr = &data[i * F81604_DATA_SIZE];
+
+		if (ptr[F81604_CMD_OFFSET] != F81604_CMD_DATA)
+			continue;
+
+		skb = alloc_can_skb(netdev, &cf);
+		if (!skb) {
+			netdev_warn(netdev, "%s: not enough memory", __func__);
+			continue;
+		}
+
+		cf->can_dlc = can_cc_dlc2len(ptr[F81604_DLC_OFFSET] & 0xF);
+
+		if (ptr[F81604_DLC_OFFSET] & F81604_EFF_BIT) {
+			cf->can_id = (ptr[F81604_ID1_OFFSET] << 21) |
+				     (ptr[F81604_ID2_OFFSET] << 13) |
+				     (ptr[F81604_ID3_OFFSET] << 5) |
+				     (ptr[F81604_ID4_OFFSET] >> 3);
+			cf->can_id |= CAN_EFF_FLAG;
+		} else {
+			cf->can_id = (ptr[F81604_ID1_OFFSET] << 3) |
+				     (ptr[F81604_ID2_OFFSET] >> 5);
+		}
+
+		if (ptr[F81604_DLC_OFFSET] & F81604_RTR_BIT) {
+			cf->can_id |= CAN_RTR_FLAG;
+		} else if (ptr[F81604_DLC_OFFSET] & F81604_EFF_BIT) {
+			memcpy(cf->data, &ptr[F81604_EFF_DATA_OFFSET],
+			       cf->can_dlc);
+		} else {
+			memcpy(cf->data, &ptr[F81604_SFF_DATA_OFFSET],
+			       cf->can_dlc);
+		}
+
+		stats->rx_packets++;
+		stats->rx_bytes += cf->can_dlc;
+		netif_rx(skb);
+	}
+}
+
+static void f81604_read_bulk_callback(struct urb *urb)
+{
+	struct net_device *netdev = urb->context;
+	u8 *data = urb->transfer_buffer;
+	int status;
+
+	if (!netif_device_present(netdev))
+		return;
+
+	switch (urb->status) {
+	case 0: /* success */
+		break;
+
+	case -ENOENT:
+	case -EPIPE:
+	case -EPROTO:
+	case -ESHUTDOWN:
+		netdev_info(netdev, "%s: URB aborted (%d)\n", __func__,
+			    urb->status);
+		return;
+
+	default:
+		netdev_info(netdev, "%s: URB aborted (%d)\n", __func__,
+			    urb->status);
+		goto resubmit_urb;
+	}
+
+	switch (data[F81604_CMD_OFFSET]) {
+	case F81604_CMD_DATA:
+		f81604_process_rx_packet(urb);
+		break;
+	default:
+		netdev_err(netdev, "unknown header: %x, len: %d\n",
+			   data[F81604_CMD_OFFSET], urb->actual_length);
+		break;
+	}
+
+resubmit_urb:
+	status = usb_submit_urb(urb, GFP_ATOMIC);
+	if (status == -ENODEV) {
+		netif_device_detach(netdev);
+	} else if (status) {
+		netdev_err(netdev, "failed resubmitting read bulk urb: %d\n",
+			   status);
+	}
+}
+
+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, "Tx URB error (%d)\n", urb->status);
+}
+
+static void f81604_handle_clear_overrun_work(struct work_struct *work)
+{
+	struct f81604_port_priv *priv;
+	struct net_device *netdev;
+
+	priv = container_of(work, struct f81604_port_priv,
+			    handle_clear_overrun_work);
+	netdev = priv->netdev;
+
+	f81604_set_sja1000_register(priv->dev, netdev->dev_id, SJA1000_CMR,
+				    CMD_CDO);
+}
+
+static void f81604_handle_clear_reg_work(struct work_struct *work)
+{
+	struct f81604_port_priv *priv;
+	struct net_device *netdev;
+	bool clear_ecc, clear_alc;
+	unsigned long flags;
+	u8 tmp;
+
+	priv = container_of(work, struct f81604_port_priv,
+			    handle_clear_reg_work);
+	netdev = priv->netdev;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	clear_alc = priv->need_clear_alc;
+	clear_ecc = priv->need_clear_ecc;
+	priv->need_clear_alc = false;
+	priv->need_clear_ecc = false;
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	if (clear_alc) {
+		f81604_get_sja1000_register(priv->dev, netdev->dev_id,
+					    SJA1000_ALC, &tmp);
+	}
+
+	if (clear_ecc) {
+		f81604_get_sja1000_register(priv->dev, netdev->dev_id,
+					    SJA1000_ECC, &tmp);
+	}
+}
+
+static void f81604_read_int_callback(struct urb *urb)
+{
+	struct net_device *netdev = urb->context;
+	struct net_device_stats *stats;
+	struct f81604_port_priv *priv;
+	enum can_state can_state;
+	enum can_state rx_state;
+	enum can_state tx_state;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+	unsigned long flags;
+	u8 rxerr, txerr;
+	u8 sr, isrc;
+	u8 alc, ecc;
+	u8 *data;
+	int r;
+
+	data = urb->transfer_buffer;
+	priv = netdev_priv(netdev);
+	can_state = priv->can.state;
+	stats = &netdev->stats;
+
+	if (!netif_device_present(netdev))
+		return;
+
+	switch (urb->status) {
+	case 0: /* success */
+		break;
+
+	case -ENOENT:
+	case -EPIPE:
+	case -EPROTO:
+	case -ESHUTDOWN:
+		netdev_info(netdev, "%s: Int URB aborted (%d)\n", __func__,
+			    urb->status);
+		return;
+
+	default:
+		netdev_info(netdev, "%s: Int URB aborted (%d)\n", __func__,
+			    urb->status);
+		goto resubmit_urb;
+	}
+
+	/* Int EP Read data format: SR/IR/IER/ALC/ECC/EWLR/RXERR/TXERR/VAL
+	 * Note: ALC/ECC will not auto clear by here, must to read clear by
+	 * read register (via handle_clear_reg_work).
+	 */
+	sr = data[0];
+	isrc = data[1];
+	alc = data[3];
+	ecc = data[4];
+	rxerr = data[6];
+	txerr = data[7];
+
+	/* handle can bus errors */
+	if (isrc & (IRQ_DOI | IRQ_EI | IRQ_BEI | IRQ_EPI | IRQ_ALI)) {
+		skb = alloc_can_err_skb(netdev, &cf);
+		if (!skb) {
+			netdev_warn(netdev,
+				    "no memory to alloc_can_err_skb\n");
+			goto resubmit_urb;
+		}
+
+		cf->data[6] = txerr;
+		cf->data[7] = rxerr;
+
+		if (isrc & IRQ_DOI) {
+			/* data overrun interrupt */
+			netdev_dbg(netdev, "data overrun interrupt\n");
+			cf->can_id |= CAN_ERR_CRTL;
+			cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+			stats->rx_over_errors++;
+			stats->rx_errors++;
+
+			schedule_work(&priv->handle_clear_overrun_work);
+		}
+
+		if (isrc & IRQ_EI) {
+			/* error warning interrupt */
+			netdev_dbg(netdev, "error warning interrupt\n");
+
+			if (sr & SR_BS)
+				can_state = CAN_STATE_BUS_OFF;
+			else if (sr & SR_ES)
+				can_state = CAN_STATE_ERROR_WARNING;
+			else
+				can_state = CAN_STATE_ERROR_ACTIVE;
+		}
+
+		if (isrc & IRQ_BEI) {
+			/* bus error interrupt */
+			netdev_dbg(netdev, "bus error interrupt\n");
+
+			priv->can.can_stats.bus_error++;
+			stats->rx_errors++;
+
+			cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+
+			/* set error type */
+			switch (ecc & ECC_MASK) {
+			case ECC_BIT:
+				cf->data[2] |= CAN_ERR_PROT_BIT;
+				break;
+			case ECC_FORM:
+				cf->data[2] |= CAN_ERR_PROT_FORM;
+				break;
+			case ECC_STUFF:
+				cf->data[2] |= CAN_ERR_PROT_STUFF;
+				break;
+			default:
+				break;
+			}
+
+			/* set error location */
+			cf->data[3] = ecc & ECC_SEG;
+
+			/* Error occurred during transmission? */
+			if ((ecc & ECC_DIR) == 0)
+				cf->data[2] |= CAN_ERR_PROT_TX;
+
+			spin_lock_irqsave(&priv->lock, flags);
+			priv->need_clear_ecc = true;
+			spin_unlock_irqrestore(&priv->lock, flags);
+
+			schedule_work(&priv->handle_clear_reg_work);
+		}
+
+		if (isrc & 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: %x\n",
+				   can_state);
+		}
+
+		if (isrc & IRQ_ALI) {
+			/* arbitration lost interrupt */
+			netdev_dbg(netdev, "arbitration lost interrupt\n");
+
+			priv->can.can_stats.arbitration_lost++;
+			stats->tx_errors++;
+			cf->can_id |= CAN_ERR_LOSTARB;
+			cf->data[0] = alc & 0x1f;
+
+			spin_lock_irqsave(&priv->lock, flags);
+			priv->need_clear_alc = true;
+			spin_unlock_irqrestore(&priv->lock, flags);
+
+			schedule_work(&priv->handle_clear_reg_work);
+		}
+
+		if (can_state != priv->can.state) {
+			tx_state = txerr >= rxerr ? can_state : 0;
+			rx_state = txerr <= rxerr ? can_state : 0;
+
+			can_change_state(netdev, cf, tx_state, rx_state);
+
+			if (can_state == CAN_STATE_BUS_OFF)
+				can_bus_off(netdev);
+		}
+
+		stats->rx_packets++;
+		stats->rx_bytes += cf->can_dlc;
+		netif_rx(skb);
+	}
+
+	/* handle TX */
+	if ((isrc & IRQ_TI) && can_state != CAN_STATE_BUS_OFF) {
+		/* transmission buffer released */
+		if (priv->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT &&
+		    !(sr & 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);
+	}
+
+resubmit_urb:
+	r = usb_submit_urb(urb, GFP_ATOMIC);
+	if (r) {
+		netdev_err(netdev,
+			   "%s: failed resubmitting int bulk urb: %d\n",
+			   __func__, r);
+
+		if (r == -ENODEV)
+			netif_device_detach(netdev);
+	}
+}
+
+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;
+	int status;
+	u8 *ptr;
+	u32 id;
+
+	if (can_dropped_invalid_skb(netdev, skb))
+		return NETDEV_TX_OK;
+
+	netif_stop_queue(netdev);
+
+	ptr = priv->bulk_write_buffer;
+	memset(ptr, 0, F81604_DATA_SIZE);
+
+	ptr[0] = F81604_CMD_DATA;
+	ptr[1] = min_t(u8, cf->can_dlc & 0xf, 8);
+
+	if (cf->can_id & CAN_EFF_FLAG) {
+		id = (cf->can_id & CAN_ERR_MASK) << 3;
+		ptr[1] |= F81604_EFF_BIT;
+		ptr[2] = (id >> 24) & 0xff;
+		ptr[3] = (id >> 16) & 0xff;
+		ptr[4] = (id >> 8) & 0xff;
+		ptr[5] = (id >> 0) & 0xff;
+		memcpy(&ptr[6], cf->data, ptr[1]);
+	} else {
+		id = (cf->can_id & CAN_ERR_MASK) << 5;
+		ptr[2] = (id >> 8) & 0xff;
+		ptr[3] = (id >> 0) & 0xff;
+		memcpy(&ptr[4], cf->data, ptr[1]);
+	}
+
+	if (cf->can_id & CAN_RTR_FLAG)
+		ptr[1] |= F81604_RTR_BIT;
+
+	can_put_echo_skb(skb, netdev, 0, 0);
+
+	status = usb_submit_urb(priv->write_urb, GFP_ATOMIC);
+	if (status) {
+		netdev_err(netdev, "%s: failed resubmitting tx bulk urb: %d\n",
+			   __func__, status);
+
+		can_free_echo_skb(netdev, 0, NULL);
+		stats->tx_dropped++;
+
+		if (status == -ENODEV)
+			netif_device_detach(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);
+	int status;
+	u8 txerr;
+	u8 rxerr;
+
+	status = f81604_get_sja1000_register(priv->dev, netdev->dev_id,
+					     SJA1000_TXERR, &txerr);
+	if (status)
+		return status;
+
+	status = f81604_get_sja1000_register(priv->dev, netdev->dev_id,
+					     SJA1000_RXERR, &rxerr);
+	if (status)
+		return status;
+
+	bec->txerr = txerr;
+	bec->rxerr = rxerr;
+
+	return 0;
+}
+
+static void f81604_remove_urbs(struct net_device *netdev)
+{
+	struct f81604_port_priv *priv = netdev_priv(netdev);
+	int i;
+
+	for (i = 0; i < F81604_MAX_RX_URBS; ++i)
+		usb_free_urb(priv->read_urb[i]);
+
+	usb_free_urb(priv->write_urb);
+	usb_free_urb(priv->int_urb);
+}
+
+static int f81604_prepare_urbs(struct net_device *netdev)
+{
+	static const u8 bulk_in_addr[F81604_MAX_DEV] = { 0x82, 0x84 };
+	static const u8 bulk_out_addr[F81604_MAX_DEV] = { 0x01, 0x03 };
+	static const u8 int_in_addr[F81604_MAX_DEV] = { 0x81, 0x83 };
+	struct f81604_port_priv *priv = netdev_priv(netdev);
+	int id = netdev->dev_id;
+	int i;
+
+	/* initialize to NULL for error recovery */
+	for (i = 0; i < F81604_MAX_RX_URBS; ++i)
+		priv->read_urb[i] = NULL;
+
+	priv->write_urb = NULL;
+	priv->int_urb = NULL;
+
+	for (i = 0; i < F81604_MAX_RX_URBS; ++i) {
+		priv->read_urb[i] = usb_alloc_urb(0, GFP_KERNEL);
+		if (!priv->read_urb[i])
+			goto error;
+
+		usb_fill_bulk_urb(priv->read_urb[i], priv->dev,
+				  usb_rcvbulkpipe(priv->dev, bulk_in_addr[id]),
+				  priv->bulk_read_buffer[i], F81604_BULK_SIZE,
+				  f81604_read_bulk_callback, netdev);
+	}
+
+	priv->write_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!priv->write_urb)
+		goto error;
+
+	usb_fill_bulk_urb(priv->write_urb, priv->dev,
+			  usb_sndbulkpipe(priv->dev, bulk_out_addr[id]),
+			  priv->bulk_write_buffer, F81604_DATA_SIZE,
+			  f81604_write_bulk_callback, netdev);
+
+	priv->int_urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!priv->int_urb)
+		goto error;
+
+	usb_fill_int_urb(priv->int_urb, priv->dev,
+			 usb_rcvintpipe(priv->dev, int_in_addr[id]),
+			 priv->int_read_buffer, F81604_INT_SIZE,
+			 f81604_read_int_callback, netdev, 1);
+
+	return 0;
+
+error:
+	f81604_remove_urbs(netdev);
+	return -ENOMEM;
+}
+
+/* Open USB device */
+static int f81604_open(struct net_device *netdev)
+{
+	int err;
+
+	err = f81604_prepare_urbs(netdev);
+	if (err)
+		return err;
+
+	err = open_candev(netdev);
+	if (err)
+		goto remove_urbs;
+
+	err = f81604_start(netdev);
+	if (err)
+		goto start_failed;
+
+	netif_start_queue(netdev);
+	return 0;
+
+start_failed:
+	if (err == -ENODEV)
+		netif_device_detach(netdev);
+
+	close_candev(netdev);
+
+remove_urbs:
+	f81604_remove_urbs(netdev);
+
+	return err;
+}
+
+/* Close USB device */
+static int f81604_close(struct net_device *netdev)
+{
+	struct f81604_port_priv *priv = netdev_priv(netdev);
+
+	f81604_set_reset_mode(netdev);
+
+	netif_stop_queue(netdev);
+	cancel_work_sync(&priv->handle_clear_overrun_work);
+	cancel_work_sync(&priv->handle_clear_reg_work);
+	close_candev(netdev);
+
+	f81604_unregister_urbs(netdev);
+	f81604_remove_urbs(netdev);
+
+	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 = "f81604",
+	.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 < F81604_MAX_DEV; ++i) {
+		if (!priv->netdev[i])
+			continue;
+
+		unregister_netdev(priv->netdev[i]);
+		free_candev(priv->netdev[i]);
+	}
+}
+
+static int f81604_probe(struct usb_interface *intf,
+			const struct usb_device_id *id)
+{
+	struct usb_device *dev = interface_to_usbdev(intf);
+	struct f81604_port_priv *port_priv;
+	struct net_device *netdev;
+	struct f81604_priv *priv;
+	int i, err;
+
+	dev_info(&intf->dev, "Detected Fintek F81604 device.\n");
+	dev_info(&intf->dev,
+		 "Please download newest driver from Fintek website\n");
+	dev_info(&intf->dev, "if you want to use customized functions.\n");
+
+	priv = devm_kzalloc(&intf->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	usb_set_intfdata(intf, priv);
+
+	for (i = 0; i < F81604_MAX_DEV; ++i) {
+		netdev = alloc_candev(sizeof(*port_priv), 1);
+		if (!netdev) {
+			dev_err(&intf->dev, "Couldn't alloc candev: %d\n", i);
+			err = -ENOMEM;
+
+			goto failure_cleanup;
+		}
+
+		port_priv = netdev_priv(netdev);
+		netdev->dev_id = i;
+
+		spin_lock_init(&port_priv->lock);
+		INIT_WORK(&port_priv->handle_clear_overrun_work,
+			  f81604_handle_clear_overrun_work);
+		INIT_WORK(&port_priv->handle_clear_reg_work,
+			  f81604_handle_clear_reg_work);
+
+		port_priv->intf = intf;
+		port_priv->dev = dev;
+		port_priv->ocr = OCR_TX0_PUSHPULL | OCR_TX1_PUSHPULL;
+		port_priv->cdr = CDR_CBP;
+		port_priv->can.state = CAN_STATE_STOPPED;
+		port_priv->can.clock.freq = 24000000 / 2;
+
+		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_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;
+
+		port_priv->can.ctrlmode_supported |= CAN_CTRLMODE_PRESUME_ACK;
+		netdev->netdev_ops = &f81604_netdev_ops;
+		netdev->flags |= IFF_ECHO;
+
+		SET_NETDEV_DEV(netdev, &intf->dev);
+
+		err = register_candev(netdev);
+		if (err) {
+			netdev_err(netdev,
+				   "couldn't register CAN device: %d\n", err);
+			free_candev(netdev);
+
+			goto failure_cleanup;
+		}
+
+		port_priv->netdev = netdev;
+		priv->netdev[i] = netdev;
+
+		dev_info(&intf->dev, "Channel #%d registered as %s\n", i,
+			 netdev->name);
+	}
+
+	return 0;
+
+failure_cleanup:
+	f81604_disconnect(intf);
+	return err;
+}
+
+static struct usb_driver f81604_driver = {
+	.name = "f81604",
+	.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