openwrt/target/linux/layerscape/patches-5.4/802-can-0019-can-flexcan-add-CAN-FD-mode-support.patch

From 2aea13a107090d05e968d7d2aa3f72380a3f1b4c Mon Sep 17 00:00:00 2001
From: Joakim Zhang <qiangqing.zhang@nxp.com>
Date: Fri, 12 Jul 2019 08:02:44 +0000
Subject: [PATCH] can: flexcan: add CAN FD mode support

This patch intends to add CAN FD mode support in driver, it means that
payload size can extend up to 64 bytes.

Bit timing always set in CBT register other than CTRL1 register when
CANFD supports BRS, it will extend the range of all CAN bit timing
variables (PRESDIV, PROPSEG, PSEG1, PSEG2 and RJW), which will improve
the bit timing accuracy.

Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/flexcan.c | 247 ++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 218 insertions(+), 29 deletions(-)

--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -52,6 +52,7 @@
 #define FLEXCAN_MCR_IRMQ		BIT(16)
 #define FLEXCAN_MCR_LPRIO_EN		BIT(13)
 #define FLEXCAN_MCR_AEN			BIT(12)
+#define FLEXCAN_MCR_FDEN		BIT(11)
 /* MCR_MAXMB: maximum used MBs is MAXMB + 1 */
 #define FLEXCAN_MCR_MAXMB(x)		((x) & 0x7f)
 #define FLEXCAN_MCR_IDAM_A		(0x0 << 8)
@@ -137,6 +138,26 @@
 	 FLEXCAN_ESR_BOFF_INT | FLEXCAN_ESR_ERR_INT | \
 	 FLEXCAN_ESR_WAK_INT)
 
+/* FLEXCAN Bit Timing register (CBT) bits */
+#define FLEXCAN_CBT_BTF			BIT(31)
+#define FLEXCAN_CBT_EPRESDIV(x)		(((x) & 0x3ff) << 21)
+#define FLEXCAN_CBT_ERJW(x)		(((x) & 0x0f) << 16)
+#define FLEXCAN_CBT_EPROPSEG(x)		(((x) & 0x3f) << 10)
+#define FLEXCAN_CBT_EPSEG1(x)		(((x) & 0x1f) << 5)
+#define FLEXCAN_CBT_EPSEG2(x)		((x) & 0x1f)
+
+/* FLEXCAN FD control register (FDCTRL) bits */
+#define FLEXCAN_FDCTRL_FDRATE		BIT(31)
+#define FLEXCAN_FDCTRL_MBDSR1(x)	(((x) & 0x3) << 19)
+#define FLEXCAN_FDCTRL_MBDSR0(x)	(((x) & 0x3) << 16)
+
+/* FLEXCAN FD Bit Timing register (FDCBT) bits */
+#define FLEXCAN_FDCBT_FPRESDIV(x)	(((x) & 0x3ff) << 20)
+#define FLEXCAN_FDCBT_FRJW(x)		(((x) & 0x07) << 16)
+#define FLEXCAN_FDCBT_FPROPSEG(x)	(((x) & 0x1f) << 10)
+#define FLEXCAN_FDCBT_FPSEG1(x)		(((x) & 0x07) << 5)
+#define FLEXCAN_FDCBT_FPSEG2(x)		((x) & 0x07)
+
 /* FLEXCAN interrupt flag register (IFLAG) bits */
 /* Errata ERR005829 step7: Reserve first valid MB */
 #define FLEXCAN_TX_MB_RESERVED_OFF_FIFO		8
@@ -161,6 +182,9 @@
 #define FLEXCAN_MB_CODE_TX_DATA		(0xc << 24)
 #define FLEXCAN_MB_CODE_TX_TANSWER	(0xe << 24)
 
+#define FLEXCAN_MB_CNT_EDL		BIT(31)
+#define FLEXCAN_MB_CNT_BRS		BIT(30)
+#define FLEXCAN_MB_CNT_ESI		BIT(29)
 #define FLEXCAN_MB_CNT_SRR		BIT(22)
 #define FLEXCAN_MB_CNT_IDE		BIT(21)
 #define FLEXCAN_MB_CNT_RTR		BIT(20)
@@ -192,6 +216,7 @@
 #define FLEXCAN_QUIRK_BROKEN_PERR_STATE	BIT(6) /* No interrupt for error passive */
 #define FLEXCAN_QUIRK_DEFAULT_BIG_ENDIAN	BIT(7) /* default to BE register access */
 #define FLEXCAN_QUIRK_SETUP_STOP_MODE		BIT(8) /* Setup stop mode to support wakeup */
+#define FLEXCAN_QUIRK_TIMESTAMP_SUPPORT_FD	BIT(9) /* Use timestamp then support can fd mode */
 
 /* Structure of the message buffer */
 struct flexcan_mb {
@@ -225,7 +250,8 @@ struct flexcan_regs {
 	u32 crcr;		/* 0x44 */
 	u32 rxfgmask;		/* 0x48 */
 	u32 rxfir;		/* 0x4c */
-	u32 _reserved3[12];	/* 0x50 */
+	u32 cbt;		/* 0x50 */
+	u32 _reserved3[11];	/* 0x54 */
 	u8 mb[2][512];		/* 0x80 */
 	/* FIFO-mode:
 	 *			MB
@@ -250,6 +276,10 @@ struct flexcan_regs {
 	u32 rerrdr;		/* 0xaf4 */
 	u32 rerrsynr;		/* 0xaf8 */
 	u32 errsr;		/* 0xafc */
+	u32 _reserved7[64];	/* 0xb00 */
+	u32 fdctrl;		/* 0xc00 */
+	u32 fdcbt;		/* 0xc04 */
+	u32 fdcrc;		/* 0xc08 */
 };
 
 struct flexcan_devtype_data {
@@ -337,6 +367,30 @@ static const struct can_bittiming_const
 	.brp_inc = 1,
 };
 
+static const struct can_bittiming_const flexcan_fd_bittiming_const = {
+	.name = DRV_NAME,
+	.tseg1_min = 2,
+	.tseg1_max = 96,
+	.tseg2_min = 2,
+	.tseg2_max = 32,
+	.sjw_max = 16,
+	.brp_min = 1,
+	.brp_max = 1024,
+	.brp_inc = 1,
+};
+
+static const struct can_bittiming_const flexcan_fd_data_bittiming_const = {
+	.name = DRV_NAME,
+	.tseg1_min = 2,
+	.tseg1_max = 39,
+	.tseg2_min = 2,
+	.tseg2_max = 8,
+	.sjw_max = 4,
+	.brp_min = 1,
+	.brp_max = 1024,
+	.brp_inc = 1,
+};
+
 /* FlexCAN module is essentially modelled as a little-endian IP in most
  * SoCs, i.e the registers as well as the message buffer areas are
  * implemented in a little-endian fashion.
@@ -631,7 +685,7 @@ static netdev_tx_t flexcan_start_xmit(st
 	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
 	u32 can_id;
 	u32 data;
-	u32 ctrl = FLEXCAN_MB_CODE_TX_DATA | (cfd->len << 16);
+	u32 ctrl = FLEXCAN_MB_CODE_TX_DATA | ((can_len2dlc(cfd->len)) << 16);
 	int i;
 
 	if (can_dropped_invalid_skb(dev, skb))
@@ -649,6 +703,9 @@ static netdev_tx_t flexcan_start_xmit(st
 	if (cfd->can_id & CAN_RTR_FLAG)
 		ctrl |= FLEXCAN_MB_CNT_RTR;
 
+	if (can_is_canfd_skb(skb))
+		ctrl |= FLEXCAN_MB_CNT_EDL;
+
 	for (i = 0; i < cfd->len; i += sizeof(u32)) {
 		data = be32_to_cpup((__be32 *)&cfd->data[i]);
 		priv->write(data, &priv->tx_mb->data[i / sizeof(u32)]);
@@ -859,7 +916,10 @@ static struct sk_buff *flexcan_mailbox_r
 		reg_ctrl = priv->read(&mb->can_ctrl);
 	}
 
-	skb = alloc_can_skb(offload->dev, (struct can_frame **)&cfd);
+	if (reg_ctrl & FLEXCAN_MB_CNT_EDL)
+		skb = alloc_canfd_skb(offload->dev, &cfd);
+	else
+		skb = alloc_can_skb(offload->dev, (struct can_frame **)&cfd);
 	if (unlikely(!skb)) {
 		skb = ERR_PTR(-ENOMEM);
 		goto mark_as_read;
@@ -874,9 +934,17 @@ static struct sk_buff *flexcan_mailbox_r
 	else
 		cfd->can_id = (reg_id >> 18) & CAN_SFF_MASK;
 
-	if (reg_ctrl & FLEXCAN_MB_CNT_RTR)
-		cfd->can_id |= CAN_RTR_FLAG;
-	cfd->len = get_can_dlc((reg_ctrl >> 16) & 0xf);
+	if (reg_ctrl & FLEXCAN_MB_CNT_EDL) {
+		cfd->len = can_dlc2len(get_canfd_dlc((reg_ctrl >> 16) & 0xf));
+	} else {
+		cfd->len = get_can_dlc((reg_ctrl >> 16) & 0xf);
+
+		if (reg_ctrl & FLEXCAN_MB_CNT_RTR)
+			cfd->can_id |= CAN_RTR_FLAG;
+	}
+
+	if (reg_ctrl & FLEXCAN_MB_CNT_ESI)
+		cfd->flags |= CANFD_ESI;
 
 	for (i = 0; i < cfd->len; i += sizeof(u32)) {
 		__be32 data = cpu_to_be32(priv->read(&mb->data[i / sizeof(u32)]));
@@ -1021,27 +1089,14 @@ static irqreturn_t flexcan_irq(int irq,
 
 static void flexcan_set_bittiming(struct net_device *dev)
 {
-	const struct flexcan_priv *priv = netdev_priv(dev);
-	const struct can_bittiming *bt = &priv->can.bittiming;
+	struct flexcan_priv *priv = netdev_priv(dev);
+	struct can_bittiming *bt = &priv->can.bittiming;
+	struct can_bittiming *dbt = &priv->can.data_bittiming;
 	struct flexcan_regs __iomem *regs = priv->regs;
-	u32 reg;
+	u32 reg, reg_cbt, reg_fdcbt;
 
 	reg = priv->read(&regs->ctrl);
-	reg &= ~(FLEXCAN_CTRL_PRESDIV(0xff) |
-		 FLEXCAN_CTRL_RJW(0x3) |
-		 FLEXCAN_CTRL_PSEG1(0x7) |
-		 FLEXCAN_CTRL_PSEG2(0x7) |
-		 FLEXCAN_CTRL_PROPSEG(0x7) |
-		 FLEXCAN_CTRL_LPB |
-		 FLEXCAN_CTRL_SMP |
-		 FLEXCAN_CTRL_LOM);
-
-	reg |= FLEXCAN_CTRL_PRESDIV(bt->brp - 1) |
-		FLEXCAN_CTRL_PSEG1(bt->phase_seg1 - 1) |
-		FLEXCAN_CTRL_PSEG2(bt->phase_seg2 - 1) |
-		FLEXCAN_CTRL_RJW(bt->sjw - 1) |
-		FLEXCAN_CTRL_PROPSEG(bt->prop_seg - 1);
-
+	reg &= ~(FLEXCAN_CTRL_LPB | FLEXCAN_CTRL_SMP | FLEXCAN_CTRL_LOM);
 	if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
 		reg |= FLEXCAN_CTRL_LPB;
 	if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
@@ -1052,9 +1107,102 @@ static void flexcan_set_bittiming(struct
 	netdev_dbg(dev, "writing ctrl=0x%08x\n", reg);
 	priv->write(reg, &regs->ctrl);
 
-	/* print chip status */
-	netdev_dbg(dev, "%s: mcr=0x%08x ctrl=0x%08x\n", __func__,
-		   priv->read(&regs->mcr), priv->read(&regs->ctrl));
+	if (priv->can.ctrlmode_supported & CAN_CTRLMODE_FD) {
+		reg_cbt = priv->read(&regs->cbt);
+		reg_cbt &= ~(FLEXCAN_CBT_EPRESDIV(0x3ff) |
+			     FLEXCAN_CBT_EPSEG1(0x1f) |
+			     FLEXCAN_CBT_EPSEG2(0x1f) |
+			     FLEXCAN_CBT_ERJW(0x1f) |
+			     FLEXCAN_CBT_EPROPSEG(0x3f) |
+			     FLEXCAN_CBT_BTF);
+
+		/* CBT[EPSEG1] is 5 bit long and CBT[EPROPSEG] is 6 bit long.
+		 * The can_calc_bittiming tries to divide the tseg1 equally
+		 * between phase_seg1 and prop_seg, which may not fit in CBT
+		 * register. Therefore, if phase_seg1 is more than possible
+		 * value, increase prop_seg and decrease phase_seg1
+		 */
+		if (bt->phase_seg1 > 0x20) {
+			bt->prop_seg += (bt->phase_seg1 - 0x20);
+			bt->phase_seg1 = 0x20;
+		}
+
+		reg_cbt = FLEXCAN_CBT_EPRESDIV(bt->brp - 1) |
+				FLEXCAN_CBT_EPSEG1(bt->phase_seg1 - 1) |
+				FLEXCAN_CBT_EPSEG2(bt->phase_seg2 - 1) |
+				FLEXCAN_CBT_ERJW(bt->sjw - 1) |
+				FLEXCAN_CBT_EPROPSEG(bt->prop_seg - 1) |
+				FLEXCAN_CBT_BTF;
+		priv->write(reg_cbt, &regs->cbt);
+
+		netdev_dbg(dev, "bt: prediv %d seg1 %d seg2 %d rjw %d propseg %d\n",
+			   bt->brp - 1, bt->phase_seg1 - 1, bt->phase_seg2 - 1,
+			   bt->sjw - 1, bt->prop_seg - 1);
+
+		if (priv->can.ctrlmode & CAN_CTRLMODE_FD) {
+			reg_fdcbt = priv->read(&regs->fdcbt);
+			reg_fdcbt &= ~(FLEXCAN_FDCBT_FPRESDIV(0x3ff) |
+				       FLEXCAN_FDCBT_FPSEG1(0x07) |
+				       FLEXCAN_FDCBT_FPSEG2(0x07) |
+				       FLEXCAN_FDCBT_FRJW(0x07) |
+				       FLEXCAN_FDCBT_FPROPSEG(0x1f));
+
+			/* FDCBT[FPSEG1] is 3 bit long and FDCBT[FPROPSEG] is 5 bit long.
+			 * The can_calc_bittiming tries to divide the tseg1 equally
+			 * between phase_seg1 and prop_seg, which may not fit in FDCBT
+			 * register. Therefore, if phase_seg1 is more than possible
+			 * value, increase prop_seg and decrease phase_seg1
+			 */
+			if (dbt->phase_seg1 > 0x8) {
+				dbt->prop_seg += (dbt->phase_seg1 - 0x8);
+				dbt->phase_seg1 = 0x8;
+			}
+
+			reg_fdcbt = FLEXCAN_FDCBT_FPRESDIV(dbt->brp - 1) |
+					FLEXCAN_FDCBT_FPSEG1(dbt->phase_seg1 - 1) |
+					FLEXCAN_FDCBT_FPSEG2(dbt->phase_seg2 - 1) |
+					FLEXCAN_FDCBT_FRJW(dbt->sjw - 1) |
+					FLEXCAN_FDCBT_FPROPSEG(dbt->prop_seg);
+			priv->write(reg_fdcbt, &regs->fdcbt);
+
+			if (bt->brp != dbt->brp)
+				netdev_warn(dev, "Warning!! data brp = %d and brp = %d don't match.\n"
+					    "flexcan may not work. consider using different bitrate or data bitrate\n",
+					    dbt->brp, bt->brp);
+
+			netdev_dbg(dev, "fdbt: prediv %d seg1 %d seg2 %d rjw %d propseg %d\n",
+				   dbt->brp - 1, dbt->phase_seg1 - 1, dbt->phase_seg2 - 1,
+				   dbt->sjw - 1, dbt->prop_seg);
+
+			netdev_dbg(dev, "%s: mcr=0x%08x ctrl=0x%08x cbt=0x%08x fdcbt=0x%08x\n",
+				   __func__, priv->read(&regs->mcr),
+				   priv->read(&regs->ctrl),
+				   priv->read(&regs->cbt),
+				   priv->read(&regs->fdcbt));
+		}
+	} else {
+		reg = priv->read(&regs->ctrl);
+		reg &= ~(FLEXCAN_CTRL_PRESDIV(0xff) |
+			 FLEXCAN_CTRL_RJW(0x3) |
+			 FLEXCAN_CTRL_PSEG1(0x7) |
+			 FLEXCAN_CTRL_PSEG2(0x7) |
+			 FLEXCAN_CTRL_PROPSEG(0x7));
+
+		reg |= FLEXCAN_CTRL_PRESDIV(bt->brp - 1) |
+			FLEXCAN_CTRL_PSEG1(bt->phase_seg1 - 1) |
+			FLEXCAN_CTRL_PSEG2(bt->phase_seg2 - 1) |
+			FLEXCAN_CTRL_RJW(bt->sjw - 1) |
+			FLEXCAN_CTRL_PROPSEG(bt->prop_seg - 1);
+		priv->write(reg, &regs->ctrl);
+
+		netdev_dbg(dev, "bt: prediv %d seg1 %d seg2 %d rjw %d propseg %d\n",
+			   bt->brp - 1, bt->phase_seg1 - 1, bt->phase_seg2 - 1,
+			   bt->sjw - 1, bt->prop_seg - 1);
+
+		/* print chip status */
+		netdev_dbg(dev, "%s: mcr=0x%08x ctrl=0x%08x\n", __func__,
+			   priv->read(&regs->mcr), priv->read(&regs->ctrl));
+	}
 }
 
 /* flexcan_chip_start
@@ -1066,7 +1214,7 @@ static int flexcan_chip_start(struct net
 {
 	struct flexcan_priv *priv = netdev_priv(dev);
 	struct flexcan_regs __iomem *regs = priv->regs;
-	u32 reg_mcr, reg_ctrl, reg_ctrl2, reg_mecr;
+	u32 reg_mcr, reg_ctrl, reg_ctrl2, reg_mecr, reg_fdctrl;
 	u64 reg_imask;
 	int err, i;
 	struct flexcan_mb __iomem *mb;
@@ -1163,6 +1311,26 @@ static int flexcan_chip_start(struct net
 	netdev_dbg(dev, "%s: writing ctrl=0x%08x", __func__, reg_ctrl);
 	priv->write(reg_ctrl, &regs->ctrl);
 
+	/* FDCTRL */
+	if (priv->can.ctrlmode_supported & CAN_CTRLMODE_FD) {
+		reg_fdctrl = priv->read(&regs->fdctrl) & ~FLEXCAN_FDCTRL_FDRATE;
+		reg_fdctrl &= ~(FLEXCAN_FDCTRL_MBDSR1(0x3) | FLEXCAN_FDCTRL_MBDSR0(0x3));
+		reg_mcr = priv->read(&regs->mcr) & ~FLEXCAN_MCR_FDEN;
+
+		/* support BRS when set CAN FD mode
+		 * 64 bytes payload per MB and 7 MBs per RAM block by default
+		 * enable CAN FD mode
+		 */
+		if (priv->can.ctrlmode & CAN_CTRLMODE_FD) {
+			reg_fdctrl |= FLEXCAN_FDCTRL_FDRATE;
+			reg_fdctrl |= FLEXCAN_FDCTRL_MBDSR1(0x3) | FLEXCAN_FDCTRL_MBDSR0(0x3);
+			reg_mcr |= FLEXCAN_MCR_FDEN;
+		}
+
+		priv->write(reg_fdctrl, &regs->fdctrl);
+		priv->write(reg_mcr, &regs->mcr);
+	}
+
 	if ((priv->devtype_data->quirks & FLEXCAN_QUIRK_ENABLE_EACEN_RRS)) {
 		reg_ctrl2 = priv->read(&regs->ctrl2);
 		reg_ctrl2 |= FLEXCAN_CTRL2_EACEN | FLEXCAN_CTRL2_RRS;
@@ -1310,6 +1478,12 @@ static int flexcan_open(struct net_devic
 	struct flexcan_priv *priv = netdev_priv(dev);
 	int err;
 
+	if ((priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES) &&
+	    (priv->can.ctrlmode & CAN_CTRLMODE_FD)) {
+		netdev_err(dev, "three samples mode and fd mode can't be used together\n");
+		return -EINVAL;
+	}
+
 	err = pm_runtime_get_sync(priv->dev);
 	if (err < 0)
 		return err;
@@ -1322,7 +1496,10 @@ static int flexcan_open(struct net_devic
 	if (err)
 		goto out_close;
 
-	priv->mb_size = sizeof(struct flexcan_mb) + CAN_MAX_DLEN;
+	if (priv->can.ctrlmode & CAN_CTRLMODE_FD)
+		priv->mb_size = sizeof(struct flexcan_mb) + CANFD_MAX_DLEN;
+	else
+		priv->mb_size = sizeof(struct flexcan_mb) + CAN_MAX_DLEN;
 	priv->mb_count = (sizeof(priv->regs->mb[0]) / priv->mb_size) +
 			 (sizeof(priv->regs->mb[1]) / priv->mb_size);
 
@@ -1667,6 +1844,18 @@ static int flexcan_probe(struct platform
 	priv->devtype_data = devtype_data;
 	priv->reg_xceiver = reg_xceiver;
 
+	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_TIMESTAMP_SUPPORT_FD) {
+		if (priv->devtype_data->quirks & FLEXCAN_QUIRK_USE_OFF_TIMESTAMP) {
+			priv->can.ctrlmode_supported |= CAN_CTRLMODE_FD;
+			priv->can.bittiming_const = &flexcan_fd_bittiming_const;
+			priv->can.data_bittiming_const = &flexcan_fd_data_bittiming_const;
+		} else {
+			dev_err(&pdev->dev, "can fd mode can't work on fifo mode\n");
+			err = -EINVAL;
+			goto failed_register;
+		}
+	}
+
 	pm_runtime_get_noresume(&pdev->dev);
 	pm_runtime_set_active(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);