[PATCH v2 3/4] can: Add driver for CAST CAN Bus Controller

[Hal Feng <hal.feng@starfivetech.com>]

From: William Qiu <william.qiu@starfivetech.com>

Add driver for CAST CAN Bus Controller used on
StarFive JH7110 SoC.

Signed-off-by: William Qiu <william.qiu@starfivetech.com>
Co-developed-by: Hal Feng <hal.feng@starfivetech.com>
Signed-off-by: Hal Feng <hal.feng@starfivetech.com>
---
 MAINTAINERS                |   8 +
 drivers/net/can/Kconfig    |   7 +
 drivers/net/can/Makefile   |   1 +
 drivers/net/can/cast_can.c | 936 +++++++++++++++++++++++++++++++++++++
 4 files changed, 952 insertions(+)
 create mode 100644 drivers/net/can/cast_can.c

diff --git a/MAINTAINERS b/MAINTAINERS
index cc40a9d9b8cd..9313b1a69e48 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5010,6 +5010,14 @@ S:	Maintained
 W:	https://wireless.wiki.kernel.org/en/users/Drivers/carl9170
 F:	drivers/net/wireless/ath/carl9170/
 
+CAST CAN DRIVER
+M:	William Qiu <william.qiu@starfivetech.com>
+M:	Hal Feng <hal.feng@starfivetech.com>
+L:	linux-can@vger.kernel.org
+S:	Supported
+F:	Documentation/devicetree/bindings/net/can/cast,can-ctrl.yaml
+F:	drivers/net/can/cast_can.c
+
 CAVIUM I2C DRIVER
 M:	Robert Richter <rric@kernel.org>
 S:	Odd Fixes
diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
index 7f9b60a42d29..a7ae8be5876f 100644
--- a/drivers/net/can/Kconfig
+++ b/drivers/net/can/Kconfig
@@ -124,6 +124,13 @@ config CAN_CAN327
 
 	  If this driver is built as a module, it will be called can327.
 
+config CAN_CASTCAN
+	tristate "CAST CAN"
+	depends on ARCH_STARFIVE || COMPILE_TEST
+	depends on COMMON_CLK && HAS_IOMEM
+	help
+	  CAST CAN driver. This driver supports both CAN and CANFD IP.
+
 config CAN_FLEXCAN
 	tristate "Support for Freescale FLEXCAN based chips"
 	depends on OF || COLDFIRE || COMPILE_TEST
diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
index 4669cd51e7bf..2f1ebd7c0efe 100644
--- a/drivers/net/can/Makefile
+++ b/drivers/net/can/Makefile
@@ -17,6 +17,7 @@ obj-y				+= softing/
 obj-$(CONFIG_CAN_AT91)		+= at91_can.o
 obj-$(CONFIG_CAN_BXCAN)		+= bxcan.o
 obj-$(CONFIG_CAN_CAN327)	+= can327.o
+obj-$(CONFIG_CAN_CASTCAN)	+= cast_can.o
 obj-$(CONFIG_CAN_CC770)		+= cc770/
 obj-$(CONFIG_CAN_C_CAN)		+= c_can/
 obj-$(CONFIG_CAN_CTUCANFD)	+= ctucanfd/
diff --git a/drivers/net/can/cast_can.c b/drivers/net/can/cast_can.c
new file mode 100644
index 000000000000..020a2eaa236b
--- /dev/null
+++ b/drivers/net/can/cast_can.c
@@ -0,0 +1,936 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CAST Controller Area Network Bus Controller Driver
+ *
+ * Copyright (c) 2022-2024 StarFive Technology Co., Ltd.
+ */
+
+#include <linux/can/dev.h>
+#include <linux/can/error.h>
+#include <linux/clk.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/of_device.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <linux/skbuff.h>
+#include <linux/string.h>
+#include <linux/types.h>
+
+#define DRIVER_NAME "cast_can"
+
+enum ccan_reg {
+	CCAN_RUBF	= 0x00,	/* Receive Buffer Registers 0x00-0x4f */
+	CCAN_RUBF_ID	= 0x00,
+	CCAN_RBUF_CTL	= 0x04,
+	CCAN_RBUF_DATA	= 0x08,
+	CCAN_TBUF	= 0x50,	/* Transmit Buffer Registers 0x50-0x97 */
+	CCAN_TBUF_ID	= 0x50,
+	CCAN_TBUF_CTL	= 0x54,
+	CCAN_TBUF_DATA	= 0x58,
+	CCAN_TTS	= 0x98,	/* Transmission Time Stamp 0x98-0x9f */
+	CCAN_CFG_STAT	= 0xa0,
+	CCAN_TCMD	= 0xa1,
+	CCAN_TCTRL	= 0xa2,
+	CCAN_RCTRL	= 0xa3,
+	CCAN_RTIE	= 0xa4,
+	CCAN_RTIF	= 0xa5,
+	CCAN_ERRINT	= 0xa6,
+	CCAN_LIMIT	= 0xa7,
+	CCAN_S_SEG_1	= 0xa8,
+	CCAN_S_SEG_2	= 0xa9,
+	CCAN_S_SJW	= 0xaa,
+	CCAN_S_PRESC	= 0xab,
+	CCAN_F_SEG_1	= 0xac,
+	CCAN_F_SEG_2	= 0xad,
+	CCAN_F_SJW	= 0xae,
+	CCAN_F_PRESC	= 0xaf,
+	CCAN_EALCAP	= 0xb0,
+	CCAN_RECNT	= 0xb2,
+	CCAN_TECNT	= 0xb3,
+};
+
+enum ccan_reg_bit_mask {
+	CCAN_RST_MASK		  = BIT(7), /* Set Reset Bit */
+	CCAN_FULLCAN_MASK	  = BIT(4),
+	CCAN_FIFO_MASK		  = BIT(5),
+	CCAN_TSONE_MASK		  = BIT(2),
+	CCAN_TSALL_MASK		  = BIT(1),
+	CCAN_LBMEMOD_MASK	  = BIT(6), /* Set loopback external mode */
+	CCAN_LBMIMOD_MASK	  = BIT(5), /* Set loopback internal mode */
+	CCAN_BUSOFF_MASK	  = BIT(0),
+	CCAN_TTSEN_MASK		  = BIT(7),
+	CCAN_BRS_MASK		  = BIT(4), /* CAN-FD Bit Rate Switch mask */
+	CCAN_EDL_MASK		  = BIT(5), /* Extended Data Length */
+	CCAN_DLC_MASK		  = GENMASK(3, 0),
+	CCAN_TENEXT_MASK	  = BIT(6),
+	CCAN_IDE_MASK		  = BIT(7),
+	CCAN_RTR_MASK		  = BIT(6),
+	CCAN_INTR_ALL_MASK	  = GENMASK(7, 0), /* All interrupts enable mask */
+	CCAN_RIE_MASK		  = BIT(7),
+	CCAN_RFIE_MASK		  = BIT(5),
+	CCAN_RAFIE_MASK		  = BIT(4),
+	CCAN_EIE_MASK		  = BIT(1),
+	CCAN_TASCTIVE_MASK	  = BIT(1),
+	CCAN_RASCTIVE_MASK	  = BIT(2),
+	CCAN_TBSEL_MASK		  = BIT(7), /* Message writen in STB */
+	CCAN_STBY_MASK		  = BIT(5),
+	CCAN_TPE_MASK		  = BIT(4), /* Transmit primary enable */
+	CCAN_TPA_MASK		  = BIT(3),
+	CCAN_SACK_MASK		  = BIT(7),
+	CCAN_RREL_MASK		  = BIT(4),
+	CCAN_RSTAT_NOT_EMPTY_MASK = GENMASK(1, 0),
+	CCAN_RIF_MASK		  = BIT(7),
+	CCAN_RAFIF_MASK		  = BIT(4),
+	CCAN_RFIF_MASK		  = BIT(5),
+	CCAN_TPIF_MASK		  = BIT(3), /* Transmission Primary Interrupt Flag */
+	CCAN_TSIF_MASK		  = BIT(2),
+	CCAN_EIF_MASK		  = BIT(1),
+	CCAN_AIF_MASK		  = BIT(0),
+	CCAN_EWARN_MASK		  = BIT(7),
+	CCAN_EPASS_MASK		  = BIT(6),
+	CCAN_EPIE_MASK		  = BIT(5),
+	CCAN_EPIF_MASK		  = BIT(4),
+	CCAN_ALIE_MASK		  = BIT(3),
+	CCAN_ALIF_MASK		  = BIT(2),
+	CCAN_BEIE_MASK		  = BIT(1),
+	CCAN_BEIF_MASK		  = BIT(0),
+	CCAN_AFWL_MASK		  = BIT(6),
+	CCAN_EWL_MASK		  = (BIT(3) | GENMASK(1, 0)),
+	CCAN_KOER_MASK		  = GENMASK(7, 5),
+	CCAN_BIT_ERROR_MASK	  = BIT(5),
+	CCAN_FORM_ERROR_MASK	  = BIT(6),
+	CCAN_STUFF_ERROR_MASK	  = GENMASK(6, 5),
+	CCAN_ACK_ERROR_MASK	  = BIT(7),
+	CCAN_CRC_ERROR_MASK	  = (BIT(7) | BIT(5)),
+	CCAN_OTH_ERROR_MASK	  = GENMASK(7, 6),
+};
+
+/* CCAN_S/F_SEG_1 bitfield shift */
+#define SEG_1_SHIFT		0
+#define SEG_2_SHIFT		8
+#define SJW_SHIFT		16
+#define PRESC_SHIFT		24
+
+enum cast_can_type {
+	CAST_CAN_TYPE_CAN = 0,
+	CAST_CAN_TYPE_CANFD,
+};
+
+struct ccan_priv {
+	struct can_priv can;
+	struct napi_struct napi;
+	struct device *dev;
+	void __iomem *reg_base;
+	struct clk_bulk_data clks[3];
+	struct reset_control *resets;
+	u32 cantype;
+};
+
+struct cast_can_data {
+	enum cast_can_type cantype;
+	const struct can_bittiming_const *bittime_const;
+	int (*syscon_update)(struct ccan_priv *priv);
+};
+
+static struct can_bittiming_const ccan_bittiming_const = {
+	.name = DRIVER_NAME,
+	.tseg1_min = 2,
+	.tseg1_max = 16,
+	.tseg2_min = 2,
+	.tseg2_max = 8,
+	.sjw_max = 4,
+	.brp_min = 1,
+	.brp_max = 256,
+	.brp_inc = 1,
+};
+
+static struct can_bittiming_const ccan_bittiming_const_canfd = {
+	.name = DRIVER_NAME,
+	.tseg1_min = 2,
+	.tseg1_max = 64,
+	.tseg2_min = 2,
+	.tseg2_max = 16,
+	.sjw_max = 16,
+	.brp_min = 1,
+	.brp_max = 256,
+	.brp_inc = 1,
+};
+
+static struct can_bittiming_const ccan_data_bittiming_const_canfd = {
+	.name = DRIVER_NAME,
+	.tseg1_min = 1,
+	.tseg1_max = 16,
+	.tseg2_min = 2,
+	.tseg2_max = 8,
+	.sjw_max = 8,
+	.brp_min = 1,
+	.brp_max = 256,
+	.brp_inc = 1,
+};
+
+static inline u32 ccan_read_reg(const struct ccan_priv *priv, u8 reg)
+{
+	return ioread32(priv->reg_base + reg);
+}
+
+static inline void ccan_write_reg(const struct ccan_priv *priv, u8 reg, u32 value)
+{
+	iowrite32(value, priv->reg_base + reg);
+}
+
+static inline u8 ccan_read_reg_8bit(const struct ccan_priv *priv,
+				    enum ccan_reg reg)
+{
+	u8 reg_down;
+	union val {
+		u8 val_8[4];
+		u32 val_32;
+	} val;
+
+	reg_down = ALIGN_DOWN(reg, 4);
+	val.val_32 = ccan_read_reg(priv, reg_down);
+	return val.val_8[reg - reg_down];
+}
+
+static inline void ccan_write_reg_8bit(const struct ccan_priv *priv,
+				       enum ccan_reg reg, u8 value)
+{
+	u8 reg_down;
+	union val {
+		u8 val_8[4];
+		u32 val_32;
+	} val;
+
+	reg_down = ALIGN_DOWN(reg, 4);
+	val.val_32 = ccan_read_reg(priv, reg_down);
+	val.val_8[reg - reg_down] = value;
+	ccan_write_reg(priv, reg_down, val.val_32);
+}
+
+static void ccan_reg_set_bits(const struct ccan_priv *priv,
+			      enum ccan_reg reg,
+			      enum ccan_reg_bit_mask bits)
+{
+	u8 val;
+
+	val = ccan_read_reg_8bit(priv, reg);
+	val |= bits;
+	ccan_write_reg_8bit(priv, reg, val);
+}
+
+static void ccan_reg_clear_bits(const struct ccan_priv *priv,
+				enum ccan_reg reg,
+				enum ccan_reg_bit_mask bits)
+{
+	u8 val;
+
+	val = ccan_read_reg_8bit(priv, reg);
+	val &= ~bits;
+	ccan_write_reg_8bit(priv, reg, val);
+}
+
+static void ccan_set_reset_mode(struct net_device *ndev)
+{
+	struct ccan_priv *priv = netdev_priv(ndev);
+
+	ccan_reg_set_bits(priv, CCAN_CFG_STAT, CCAN_RST_MASK);
+}
+
+static int ccan_bittime_configuration(struct net_device *ndev)
+{
+	struct ccan_priv *priv = netdev_priv(ndev);
+	struct can_bittiming *bt = &priv->can.bittiming;
+	struct can_bittiming *dbt = &priv->can.data_bittiming;
+	u32 bittiming, data_bittiming;
+	u8 reset_test;
+
+	reset_test = ccan_read_reg_8bit(priv, CCAN_CFG_STAT);
+
+	if (!(reset_test & CCAN_RST_MASK)) {
+		netdev_alert(ndev, "Not in reset mode, cannot set bit timing\n");
+		return -EPERM;
+	}
+
+	/* Check the bittime parameter */
+	if ((((int)(bt->phase_seg1 + bt->prop_seg + 1) - 2) < 0) ||
+	    (((int)(bt->phase_seg2) - 1) < 0) ||
+	    (((int)(bt->sjw) - 1) < 0) ||
+	    (((int)(bt->brp) - 1) < 0))
+		return -EINVAL;
+
+	bittiming = ((bt->phase_seg1 + bt->prop_seg + 1 - 2) << SEG_1_SHIFT) |
+			 ((bt->phase_seg2 - 1) << SEG_2_SHIFT) |
+			 ((bt->sjw - 1) << SJW_SHIFT) |
+			 ((bt->brp - 1) << PRESC_SHIFT);
+
+	ccan_write_reg(priv, CCAN_S_SEG_1, bittiming);
+
+	if (priv->cantype == CAST_CAN_TYPE_CANFD) {
+		if ((((int)(dbt->phase_seg1 + dbt->prop_seg + 1) - 2) < 0) ||
+		    (((int)(dbt->phase_seg2) - 1) < 0) ||
+		    (((int)(dbt->sjw) - 1) < 0) ||
+		    (((int)(dbt->brp) - 1) < 0))
+			return -EINVAL;
+
+		data_bittiming = ((dbt->phase_seg1 + dbt->prop_seg + 1 - 2) << SEG_1_SHIFT) |
+				 ((dbt->phase_seg2 - 1) << SEG_2_SHIFT) |
+				 ((dbt->sjw - 1) << SJW_SHIFT) |
+				 ((dbt->brp - 1) << PRESC_SHIFT);
+
+		ccan_write_reg(priv, CCAN_F_SEG_1, data_bittiming);
+	}
+
+	ccan_reg_clear_bits(priv, CCAN_CFG_STAT, CCAN_RST_MASK);
+
+	netdev_dbg(ndev, "Slow bit rate: %08x\n", ccan_read_reg(priv, CCAN_S_SEG_1));
+	netdev_dbg(ndev, "Fast bit rate: %08x\n", ccan_read_reg(priv, CCAN_F_SEG_1));
+
+	return 0;
+}
+
+static int ccan_chip_start(struct net_device *ndev)
+{
+	struct ccan_priv *priv = netdev_priv(ndev);
+	int err;
+
+	ccan_set_reset_mode(ndev);
+
+	err = ccan_bittime_configuration(ndev);
+	if (err) {
+		netdev_err(ndev, "Bittime setting failed!\n");
+		return err;
+	}
+
+	/* Set Almost Full Warning Limit */
+	ccan_reg_set_bits(priv, CCAN_LIMIT, CCAN_AFWL_MASK);
+
+	/* Programmable Error Warning Limit = (EWL+1)*8. Set EWL=11->Error Warning=96 */
+	ccan_reg_set_bits(priv, CCAN_LIMIT, CCAN_EWL_MASK);
+
+	/* Interrupts enable */
+	ccan_write_reg_8bit(priv, CCAN_RTIE, CCAN_INTR_ALL_MASK);
+
+	/* Error Interrupts enable(Error Passive and Bus Error) */
+	ccan_reg_set_bits(priv, CCAN_ERRINT, CCAN_EPIE_MASK);
+
+	/* Check whether it is loopback mode or normal mode */
+	if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
+		ccan_reg_set_bits(priv, CCAN_CFG_STAT, CCAN_LBMIMOD_MASK);
+	else
+		ccan_reg_clear_bits(priv, CCAN_CFG_STAT, CCAN_LBMEMOD_MASK | CCAN_LBMIMOD_MASK);
+
+	priv->can.state = CAN_STATE_ERROR_ACTIVE;
+
+	return 0;
+}
+
+static int ccan_do_set_mode(struct net_device *ndev, enum can_mode mode)
+{
+	int ret;
+
+	switch (mode) {
+	case CAN_MODE_START:
+		ret = ccan_chip_start(ndev);
+		if (ret) {
+			netdev_err(ndev, "Could not start CAN device !\n");
+			return ret;
+		}
+		netif_wake_queue(ndev);
+		break;
+	default:
+		ret = -EOPNOTSUPP;
+		break;
+	}
+
+	return ret;
+}
+
+static void ccan_tx_interrupt(struct net_device *ndev, u8 isr)
+{
+	struct ccan_priv *priv = netdev_priv(ndev);
+
+	/* wait till transmission of the PTB or STB finished */
+	while (isr & (CCAN_TPIF_MASK | CCAN_TSIF_MASK)) {
+		if (isr & CCAN_TPIF_MASK)
+			ccan_reg_set_bits(priv, CCAN_RTIF, CCAN_TPIF_MASK);
+
+		if (isr & CCAN_TSIF_MASK)
+			ccan_reg_set_bits(priv, CCAN_RTIF, CCAN_TSIF_MASK);
+
+		isr = ccan_read_reg_8bit(priv, CCAN_RTIF);
+	}
+
+	ndev->stats.tx_bytes += can_get_echo_skb(ndev, 0, NULL);
+	ndev->stats.tx_packets++;
+	netif_wake_queue(ndev);
+}
+
+static void ccan_rxfull_interrupt(struct net_device *ndev, u8 isr)
+{
+	struct ccan_priv *priv = netdev_priv(ndev);
+
+	if (isr & CCAN_RAFIF_MASK)
+		ccan_reg_set_bits(priv, CCAN_RTIF, CCAN_RAFIF_MASK);
+
+	if (isr & (CCAN_RAFIF_MASK | CCAN_RFIF_MASK))
+		ccan_reg_set_bits(priv, CCAN_RTIF, CCAN_RAFIF_MASK | CCAN_RFIF_MASK);
+}
+
+static enum can_state ccan_get_chip_status(struct net_device *ndev)
+{
+	struct ccan_priv *priv = netdev_priv(ndev);
+	u8 can_stat, eir;
+
+	can_stat = ccan_read_reg_8bit(priv, CCAN_CFG_STAT);
+	eir = ccan_read_reg_8bit(priv, CCAN_ERRINT);
+
+	if (can_stat & CCAN_BUSOFF_MASK)
+		return CAN_STATE_BUS_OFF;
+
+	if (eir & CCAN_EPASS_MASK)
+		return CAN_STATE_ERROR_PASSIVE;
+
+	if (eir & CCAN_EWARN_MASK)
+		return CAN_STATE_ERROR_WARNING;
+
+	return CAN_STATE_ERROR_ACTIVE;
+}
+
+static void ccan_error_interrupt(struct net_device *ndev, u8 isr, u8 eir)
+{
+	struct ccan_priv *priv = netdev_priv(ndev);
+	struct net_device_stats *stats = &ndev->stats;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+	u8 koer, recnt = 0, tecnt = 0, can_stat = 0;
+
+	skb = alloc_can_err_skb(ndev, &cf);
+
+	koer = ccan_read_reg_8bit(priv, CCAN_EALCAP) & CCAN_KOER_MASK;
+	recnt = ccan_read_reg_8bit(priv, CCAN_RECNT);
+	tecnt = ccan_read_reg_8bit(priv, CCAN_TECNT);
+
+	/* Read CAN status */
+	can_stat = ccan_read_reg_8bit(priv, CCAN_CFG_STAT);
+
+	/* Bus off ---> active error mode */
+	if ((isr & CCAN_EIF_MASK) && priv->can.state == CAN_STATE_BUS_OFF)
+		priv->can.state = ccan_get_chip_status(ndev);
+
+	/* State selection */
+	if (can_stat & CCAN_BUSOFF_MASK) {
+		priv->can.state = ccan_get_chip_status(ndev);
+		priv->can.can_stats.bus_off++;
+		ccan_reg_set_bits(priv, CCAN_CFG_STAT, CCAN_BUSOFF_MASK);
+		can_bus_off(ndev);
+		if (skb)
+			cf->can_id |= CAN_ERR_BUSOFF;
+	} else if (eir & CCAN_EPASS_MASK) {
+		priv->can.state = ccan_get_chip_status(ndev);
+		priv->can.can_stats.error_passive++;
+		if (skb) {
+			cf->can_id |= CAN_ERR_CRTL;
+			cf->data[1] |= (recnt > 127) ? CAN_ERR_CRTL_RX_PASSIVE : 0;
+			cf->data[1] |= (tecnt > 127) ? CAN_ERR_CRTL_TX_PASSIVE : 0;
+			cf->data[6] = tecnt;
+			cf->data[7] = recnt;
+		}
+	} else if (eir & CCAN_EWARN_MASK) {
+		priv->can.state = ccan_get_chip_status(ndev);
+		priv->can.can_stats.error_warning++;
+		if (skb) {
+			cf->can_id |= CAN_ERR_CRTL;
+			cf->data[1] |= (recnt > 95) ? CAN_ERR_CRTL_RX_WARNING : 0;
+			cf->data[1] |= (tecnt > 95) ? CAN_ERR_CRTL_TX_WARNING : 0;
+			cf->data[6] = tecnt;
+			cf->data[7] = recnt;
+		}
+	}
+
+	/* Check for in protocol defined error interrupt */
+	if (eir & CCAN_BEIF_MASK) {
+		if (skb)
+			cf->can_id |= CAN_ERR_BUSERROR | CAN_ERR_PROT;
+
+		if (koer == CCAN_BIT_ERROR_MASK) {
+			stats->tx_errors++;
+			if (skb)
+				cf->data[2] = CAN_ERR_PROT_BIT;
+		} else if (koer == CCAN_FORM_ERROR_MASK) {
+			stats->rx_errors++;
+			if (skb)
+				cf->data[2] = CAN_ERR_PROT_FORM;
+		} else if (koer == CCAN_STUFF_ERROR_MASK) {
+			stats->rx_errors++;
+			if (skb)
+				cf->data[3] = CAN_ERR_PROT_STUFF;
+		} else if (koer == CCAN_ACK_ERROR_MASK) {
+			stats->tx_errors++;
+			if (skb)
+				cf->data[2] = CAN_ERR_PROT_LOC_ACK;
+		} else if (koer == CCAN_CRC_ERROR_MASK) {
+			stats->rx_errors++;
+			if (skb)
+				cf->data[2] = CAN_ERR_PROT_LOC_CRC_SEQ;
+		}
+		priv->can.can_stats.bus_error++;
+	}
+
+	if (skb) {
+		stats->rx_packets++;
+		stats->rx_bytes += cf->can_dlc;
+		netif_rx(skb);
+	}
+
+	netdev_dbg(ndev, "Recnt is 0x%02x", ccan_read_reg_8bit(priv, CCAN_RECNT));
+	netdev_dbg(ndev, "Tecnt is 0x%02x", ccan_read_reg_8bit(priv, CCAN_TECNT));
+}
+
+static irqreturn_t ccan_interrupt(int irq, void *dev_id)
+{
+	struct net_device *ndev = (struct net_device *)dev_id;
+	struct ccan_priv *priv = netdev_priv(ndev);
+	u8 isr, eir;
+	u8 isr_handled = 0, eir_handled = 0;
+
+	/* Read the value of interrupt status register */
+	isr = ccan_read_reg_8bit(priv, CCAN_RTIF);
+
+	/* Read the value of error interrupt register */
+	eir = ccan_read_reg_8bit(priv, CCAN_ERRINT);
+
+	/* Check for Tx interrupt and processing it */
+	if (isr & (CCAN_TPIF_MASK | CCAN_TSIF_MASK)) {
+		ccan_tx_interrupt(ndev, isr);
+		isr_handled |= (CCAN_TPIF_MASK | CCAN_TSIF_MASK);
+	}
+
+	if (isr & (CCAN_RAFIF_MASK | CCAN_RFIF_MASK)) {
+		ccan_rxfull_interrupt(ndev, isr);
+		isr_handled |= (CCAN_RAFIF_MASK | CCAN_RFIF_MASK);
+	}
+
+	/* Check Rx interrupt and processing the receive interrupt routine */
+	if (isr & CCAN_RIF_MASK) {
+		ccan_reg_clear_bits(priv, CCAN_RTIE, CCAN_RIE_MASK);
+		ccan_reg_set_bits(priv, CCAN_RTIF, CCAN_RIF_MASK);
+
+		napi_schedule(&priv->napi);
+		isr_handled |= CCAN_RIF_MASK;
+	}
+
+	if ((isr & CCAN_EIF_MASK) | (eir & (CCAN_EPIF_MASK | CCAN_BEIF_MASK))) {
+		/* Reset EPIF and BEIF. Reset EIF */
+		ccan_reg_set_bits(priv, CCAN_ERRINT, eir & (CCAN_EPIF_MASK | CCAN_BEIF_MASK));
+		ccan_reg_set_bits(priv, CCAN_RTIF, isr & CCAN_EIF_MASK);
+
+		ccan_error_interrupt(ndev, isr, eir);
+
+		isr_handled |= CCAN_EIF_MASK;
+		eir_handled |= (CCAN_EPIF_MASK | CCAN_BEIF_MASK);
+	}
+
+	if (isr_handled == 0 && eir_handled == 0) {
+		netdev_err(ndev, "Unhandled interrupt!\n");
+		return IRQ_NONE;
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int ccan_open(struct net_device *ndev)
+{
+	struct ccan_priv *priv = netdev_priv(ndev);
+	int ret;
+
+	ret = clk_bulk_prepare_enable(ARRAY_SIZE(priv->clks), priv->clks);
+	if (ret) {
+		netdev_err(ndev, "Failed to enable CAN clocks\n");
+		return ret;
+	}
+
+	/* Set chip into reset mode */
+	ccan_set_reset_mode(ndev);
+
+	/* Common open */
+	ret = open_candev(ndev);
+	if (ret)
+		goto clk_exit;
+
+	/* Register interrupt handler */
+	ret = devm_request_irq(priv->dev, ndev->irq, ccan_interrupt, IRQF_SHARED,
+			       ndev->name, ndev);
+	if (ret) {
+		netdev_err(ndev, "Request_irq err: %d\n", ret);
+		goto candev_exit;
+	}
+
+	ret = ccan_chip_start(ndev);
+	if (ret) {
+		netdev_err(ndev, "Could not start CAN device !\n");
+		goto candev_exit;
+	}
+
+	napi_enable(&priv->napi);
+	netif_start_queue(ndev);
+
+	return 0;
+
+candev_exit:
+	close_candev(ndev);
+clk_exit:
+	clk_bulk_disable_unprepare(ARRAY_SIZE(priv->clks), priv->clks);
+	return ret;
+}
+
+static int ccan_close(struct net_device *ndev)
+{
+	struct ccan_priv *priv = netdev_priv(ndev);
+
+	netif_stop_queue(ndev);
+	napi_disable(&priv->napi);
+
+	ccan_set_reset_mode(ndev);
+	priv->can.state = CAN_STATE_STOPPED;
+
+	close_candev(ndev);
+	clk_bulk_disable_unprepare(ARRAY_SIZE(priv->clks), priv->clks);
+
+	return 0;
+}
+
+static netdev_tx_t ccan_start_xmit(struct sk_buff *skb, struct net_device *ndev)
+{
+	struct ccan_priv *priv = netdev_priv(ndev);
+	struct canfd_frame *cf = (struct canfd_frame *)skb->data;
+	u32 id, ctl, addr_off = CCAN_TBUF_DATA;
+	int i;
+
+	if (can_dropped_invalid_skb(ndev, skb))
+		return NETDEV_TX_OK;
+
+	netif_stop_queue(ndev);
+
+	/* Work in XMIT_PTB mode */
+	ccan_reg_clear_bits(priv, CCAN_TCMD, CCAN_TBSEL_MASK);
+
+	ccan_reg_clear_bits(priv, CCAN_TCMD, CCAN_STBY_MASK);
+
+	id = cf->can_id & ((cf->can_id & CAN_EFF_FLAG) ? CAN_EFF_MASK : CAN_SFF_MASK);
+
+	ctl = can_fd_len2dlc(cf->len);
+	ctl = (cf->can_id & CAN_EFF_FLAG) ? (ctl | CCAN_IDE_MASK) : (ctl & ~CCAN_IDE_MASK);
+
+	if (priv->cantype == CAST_CAN_TYPE_CANFD && can_is_canfd_skb(skb)) {
+		ctl |= (cf->flags & CANFD_BRS) ? (CCAN_BRS_MASK | CCAN_EDL_MASK) : CCAN_EDL_MASK;
+
+		for (i = 0; i < cf->len; i += 4) {
+			ccan_write_reg(priv, addr_off, *((u32 *)(cf->data + i)));
+			addr_off += 4;
+		}
+	} else {
+		ctl &= ~(CCAN_EDL_MASK | CCAN_BRS_MASK);
+
+		if (cf->can_id & CAN_RTR_FLAG) {
+			ctl |= CCAN_RTR_MASK;
+		} else {
+			ctl &= ~CCAN_RTR_MASK;
+			ccan_write_reg(priv, addr_off, *((u32 *)(cf->data + 0)));
+			ccan_write_reg(priv, addr_off + 4, *((u32 *)(cf->data + 4)));
+		}
+	}
+
+	ccan_write_reg(priv, CCAN_TBUF_ID, id);
+	ccan_write_reg(priv, CCAN_TBUF_CTL, ctl);
+	ccan_reg_set_bits(priv, CCAN_TCMD, CCAN_TPE_MASK);
+
+	can_put_echo_skb(skb, ndev, 0, 0);
+
+	return NETDEV_TX_OK;
+}
+
+static const struct net_device_ops ccan_netdev_ops = {
+	.ndo_open = ccan_open,
+	.ndo_stop = ccan_close,
+	.ndo_start_xmit = ccan_start_xmit,
+	.ndo_change_mtu = can_change_mtu,
+};
+
+static int ccan_rx(struct net_device *ndev)
+{
+	struct ccan_priv *priv = netdev_priv(ndev);
+	struct net_device_stats *stats = &ndev->stats;
+	struct canfd_frame *cf_fd;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+	u32 can_id;
+	u8 dlc, control;
+	int i;
+
+	control = ccan_read_reg_8bit(priv, CCAN_RBUF_CTL);
+	can_id = ccan_read_reg(priv, CCAN_RUBF_ID);
+	dlc = ccan_read_reg_8bit(priv, CCAN_RBUF_CTL) & CCAN_DLC_MASK;
+
+	if (control & CCAN_EDL_MASK)
+		/* allocate sk_buffer for canfd frame */
+		skb = alloc_canfd_skb(ndev, &cf_fd);
+	else
+		/* allocate sk_buffer for can frame */
+		skb = alloc_can_skb(ndev, &cf);
+
+	if (!skb) {
+		stats->rx_dropped++;
+		return 0;
+	}
+
+	/* Change the CANFD or CAN2.0 data into socketcan data format */
+	if (control & CCAN_EDL_MASK)
+		cf_fd->len = can_fd_dlc2len(dlc);
+	else
+		cf->can_dlc = can_cc_dlc2len(dlc);
+
+	/* Change the CANFD or CAN2.0 id into socketcan id format */
+	if (control & CCAN_EDL_MASK) {
+		cf_fd->can_id = can_id;
+		cf_fd->can_id = (control & CCAN_IDE_MASK) ? (cf_fd->can_id | CAN_EFF_FLAG) :
+			     (cf_fd->can_id & ~CAN_EFF_FLAG);
+	} else {
+		cf->can_id = can_id;
+		cf->can_id = (control & CCAN_IDE_MASK) ? (cf->can_id | CAN_EFF_FLAG) :
+			     (cf->can_id & ~CAN_EFF_FLAG);
+	}
+
+	if (!(control & CCAN_EDL_MASK))
+		if (control & CCAN_RTR_MASK)
+			cf->can_id |= CAN_RTR_FLAG;
+
+	if (control & CCAN_EDL_MASK) {
+		for (i = 0; i < cf_fd->len; i += 4)
+			*((u32 *)(cf_fd->data + i)) = ccan_read_reg(priv, CCAN_RBUF_DATA + i);
+	} else {
+		/* skb reads the received datas, if the RTR bit not set */
+		if (!(control & CCAN_RTR_MASK)) {
+			*((u32 *)(cf->data + 0)) = ccan_read_reg(priv, CCAN_RBUF_DATA);
+			*((u32 *)(cf->data + 4)) = ccan_read_reg(priv, CCAN_RBUF_DATA + 4);
+		}
+	}
+
+	ccan_reg_set_bits(priv, CCAN_RCTRL, CCAN_RREL_MASK);
+
+	stats->rx_bytes += (control & CCAN_EDL_MASK) ? cf_fd->len : cf->can_dlc;
+	stats->rx_packets++;
+	netif_receive_skb(skb);
+
+	return 1;
+}
+
+static int ccan_rx_poll(struct napi_struct *napi, int quota)
+{
+	struct net_device *ndev = napi->dev;
+	struct ccan_priv *priv = netdev_priv(ndev);
+	int work_done = 0;
+	u8 rx_status = 0;
+
+	rx_status = ccan_read_reg_8bit(priv, CCAN_RCTRL);
+
+	/* Clear receive interrupt and deal with all the received frames */
+	while ((rx_status & CCAN_RSTAT_NOT_EMPTY_MASK) && (work_done < quota)) {
+		work_done += ccan_rx(ndev);
+
+		rx_status = ccan_read_reg_8bit(priv, CCAN_RCTRL);
+	}
+
+	napi_complete(napi);
+	ccan_reg_set_bits(priv, CCAN_RTIE, CCAN_RIE_MASK);
+
+	return work_done;
+}
+
+static int ccan_driver_probe(struct platform_device *pdev)
+{
+	struct net_device *ndev;
+	struct ccan_priv *priv;
+	const struct cast_can_data *ddata;
+	void __iomem *addr;
+	int ret;
+
+	addr = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(addr)) {
+		ret = PTR_ERR(addr);
+		goto exit;
+	}
+
+	ddata = of_device_get_match_data(&pdev->dev);
+	if (!ddata)
+		return -ENODEV;
+
+	ndev = alloc_candev(sizeof(struct ccan_priv), 1);
+	if (!ndev) {
+		ret = -ENOMEM;
+		goto exit;
+	}
+
+	priv = netdev_priv(ndev);
+	priv->dev = &pdev->dev;
+	priv->cantype = ddata->cantype;
+	priv->can.bittiming_const = ddata->bittime_const;
+
+	if (ddata->syscon_update) {
+		ret = ddata->syscon_update(priv);
+		if (ret)
+			goto free_exit;
+	}
+
+	priv->clks[0].id = "apb";
+	priv->clks[1].id = "timer";
+	priv->clks[2].id = "core";
+
+	ret = devm_clk_bulk_get(&pdev->dev, ARRAY_SIZE(priv->clks), priv->clks);
+	if (ret) {
+		ret = dev_err_probe(&pdev->dev, ret, "Failed to get CAN clocks\n");
+		goto free_exit;
+	}
+
+	ret = clk_bulk_prepare_enable(ARRAY_SIZE(priv->clks), priv->clks);
+	if (ret) {
+		ret = dev_err_probe(&pdev->dev, ret, "Failed to enable CAN clocks\n");
+		goto free_exit;
+	}
+
+	priv->resets = devm_reset_control_array_get_exclusive(&pdev->dev);
+	if (IS_ERR(priv->resets)) {
+		ret = dev_err_probe(&pdev->dev, PTR_ERR(priv->resets),
+				    "Failed to get CAN resets");
+		goto clk_exit;
+	}
+
+	ret = reset_control_deassert(priv->resets);
+	if (ret)
+		goto clk_exit;
+
+	if (priv->cantype == CAST_CAN_TYPE_CANFD) {
+		priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK | CAN_CTRLMODE_FD;
+		priv->can.data_bittiming_const = &ccan_data_bittiming_const_canfd;
+	} else {
+		priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK;
+	}
+
+	priv->reg_base = addr;
+	priv->can.clock.freq = clk_get_rate(priv->clks[2].clk);
+	priv->can.do_set_mode = ccan_do_set_mode;
+	ndev->irq = platform_get_irq(pdev, 0);
+
+	/* We support local echo */
+	ndev->flags |= IFF_ECHO;
+	ndev->netdev_ops = &ccan_netdev_ops;
+
+	platform_set_drvdata(pdev, ndev);
+	SET_NETDEV_DEV(ndev, &pdev->dev);
+
+	netif_napi_add_tx_weight(ndev, &priv->napi, ccan_rx_poll, 16);
+	ret = register_candev(ndev);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to register (err=%d)\n", ret);
+		goto reset_exit;
+	}
+
+	dev_dbg(&pdev->dev, "Driver registered: regs=%p, irp=%d, clock=%d\n",
+		priv->reg_base, ndev->irq, priv->can.clock.freq);
+
+	return 0;
+
+reset_exit:
+	reset_control_assert(priv->resets);
+clk_exit:
+	clk_bulk_disable_unprepare(ARRAY_SIZE(priv->clks), priv->clks);
+free_exit:
+	free_candev(ndev);
+exit:
+	return ret;
+}
+
+static void ccan_driver_remove(struct platform_device *pdev)
+{
+	struct net_device *ndev = platform_get_drvdata(pdev);
+	struct ccan_priv *priv = netdev_priv(ndev);
+
+	reset_control_assert(priv->resets);
+	clk_bulk_disable_unprepare(ARRAY_SIZE(priv->clks), priv->clks);
+
+	unregister_candev(ndev);
+	netif_napi_del(&priv->napi);
+	free_candev(ndev);
+}
+
+static const struct cast_can_data ccan_canfd_data = {
+	.cantype = CAST_CAN_TYPE_CANFD,
+	.bittime_const = &ccan_bittiming_const_canfd,
+};
+
+static int sf_jh7110_syscon_update(struct ccan_priv *priv)
+{
+	struct of_phandle_args args;
+	struct regmap *syscon;
+	u32 syscon_offset, syscon_shift, syscon_mask, regval;
+	int ret;
+
+	ret = of_parse_phandle_with_fixed_args(priv->dev->of_node,
+					       "starfive,syscon", 3, 0, &args);
+	if (ret) {
+		dev_err(priv->dev, "Failed to parse starfive,syscon\n");
+		return -EINVAL;
+	}
+
+	syscon = syscon_node_to_regmap(args.np);
+	of_node_put(args.np);
+	if (IS_ERR(syscon))
+		return PTR_ERR(syscon);
+
+	syscon_offset = args.args[0];
+	syscon_shift  = args.args[1];
+	syscon_mask   = args.args[2];
+
+	/* Enable can2.0/canfd function */
+	regval = priv->cantype << syscon_shift;
+	ret = regmap_update_bits(syscon, syscon_offset, syscon_mask, regval);
+
+	return ret;
+}
+
+static const struct cast_can_data sf_jh7110_can_data = {
+	.cantype = CAST_CAN_TYPE_CAN,
+	.bittime_const = &ccan_bittiming_const,
+	.syscon_update = sf_jh7110_syscon_update,
+};
+
+static const struct of_device_id ccan_of_match[] = {
+	{ .compatible = "cast,can-ctrl-fd-7x10N00S00", .data = &ccan_canfd_data },
+	{ .compatible = "starfive,jh7110-can", .data = &sf_jh7110_can_data },
+	{ /* end of list */ },
+};
+MODULE_DEVICE_TABLE(of, ccan_of_match);
+
+static struct platform_driver ccan_driver = {
+	.probe          = ccan_driver_probe,
+	.remove         = ccan_driver_remove,
+	.driver = {
+		.name  = DRIVER_NAME,
+		.of_match_table = ccan_of_match,
+	},
+};
+module_platform_driver(ccan_driver);
+
+MODULE_DESCRIPTION("CAST CAN Bus Controller Driver");
+MODULE_AUTHOR("Fraunhofer IPMS");
+MODULE_AUTHOR("William Qiu <william.qiu@starfivetech.com>");
+MODULE_AUTHOR("Hal Feng <hal.feng@starfivetech.com>");
+MODULE_LICENSE("GPL");
-- 
2.43.2