can: mscan-mpc5xxx: add support for the MPC512x processor

The main differences compared to the MSCAN on the MPC5200 are:

- More flexibility in choosing the CAN source clock and frequency:

  Three different clock sources can be selected: "ip", "ref" or "sys".
  For the latter two, a clock divider can be defined as well. If the
  clock source is not specified by the device tree, we first try to
  find an optimal CAN source clock based on the system clock. If that
  is not possible, the reference clock will be used.

- The behavior of bus-off recovery is configurable:

  To comply with the usual handling of Socket-CAN bus-off recovery,
  "recovery on request" is selected (instead of automatic recovery).

Note that only MPC5121 Rev. 2 and later is supported.

Signed-off-by: Wolfgang Grandegger <wg@denx.de>
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 41 insertions, 10 deletions

diff --git a/drivers/net/can/mscan/mscan.c b/drivers/net/can/mscan/mscan.c
index 0dcbe8c..500d189 100644
--- a/drivers/net/can/mscan/mscan.c
+++ b/drivers/net/can/mscan/mscan.c
@@ -152,6 +152,12 @@ static int mscan_start(struct net_device *dev)
 	priv->shadow_canrier = 0;
 	priv->flags = 0;
 
+	if (priv->type == MSCAN_TYPE_MPC5121) {
+		/* Clear pending bus-off condition */
+		if (in_8(&regs->canmisc) & MSCAN_BOHOLD)
+			out_8(&regs->canmisc, MSCAN_BOHOLD);
+	}
+
 	err = mscan_set_mode(dev, MSCAN_NORMAL_MODE);
 	if (err)
 		return err;
@@ -163,8 +169,29 @@ static int mscan_start(struct net_device *dev)
 	out_8(&regs->cantier, 0);
 
 	/* Enable receive interrupts. */
-	out_8(&regs->canrier, MSCAN_OVRIE | MSCAN_RXFIE | MSCAN_CSCIE |
-	      MSCAN_RSTATE1 | MSCAN_RSTATE0 | MSCAN_TSTATE1 | MSCAN_TSTATE0);
+	out_8(&regs->canrier, MSCAN_RX_INTS_ENABLE);
+
+	return 0;
+}
+
+static int mscan_restart(struct net_device *dev)
+{
+	struct mscan_priv *priv = netdev_priv(dev);
+
+	if (priv->type == MSCAN_TYPE_MPC5121) {
+		struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
+
+		priv->can.state = CAN_STATE_ERROR_ACTIVE;
+		WARN(!(in_8(&regs->canmisc) & MSCAN_BOHOLD),
+		     "bus-off state expected");
+		out_8(&regs->canmisc, MSCAN_BOHOLD);
+		/* Re-enable receive interrupts. */
+		out_8(&regs->canrier, MSCAN_RX_INTS_ENABLE);
+	} else {
+		if (priv->can.state <= CAN_STATE_BUS_OFF)
+			mscan_set_mode(dev, MSCAN_INIT_MODE);
+		return mscan_start(dev);
+	}
 
 	return 0;
 }
@@ -362,9 +389,12 @@ static void mscan_get_err_frame(struct net_device *dev, struct can_frame *frame,
 			 * automatically. To avoid that we stop the chip doing
 			 * a light-weight stop (we are in irq-context).
 			 */
-			out_8(&regs->cantier, 0);
-			out_8(&regs->canrier, 0);
-			setbits8(&regs->canctl0, MSCAN_SLPRQ | MSCAN_INITRQ);
+			if (priv->type != MSCAN_TYPE_MPC5121) {
+				out_8(&regs->cantier, 0);
+				out_8(&regs->canrier, 0);
+				setbits8(&regs->canctl0,
+					 MSCAN_SLPRQ | MSCAN_INITRQ);
+			}
 			can_bus_off(dev);
 			break;
 		default:
@@ -494,9 +524,7 @@ static int mscan_do_set_mode(struct net_device *dev, enum can_mode mode)
 
 	switch (mode) {
 	case CAN_MODE_START:
-		if (priv->can.state <= CAN_STATE_BUS_OFF)
-			mscan_set_mode(dev, MSCAN_INIT_MODE);
-		ret = mscan_start(dev);
+		ret = mscan_restart(dev);
 		if (ret)
 			break;
 		if (netif_queue_stopped(dev))
@@ -595,18 +623,21 @@ static const struct net_device_ops mscan_netdev_ops = {
        .ndo_start_xmit         = mscan_start_xmit,
 };
 
-int register_mscandev(struct net_device *dev, int clock_src)
+int register_mscandev(struct net_device *dev, int mscan_clksrc)
 {
 	struct mscan_priv *priv = netdev_priv(dev);
 	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
 	u8 ctl1;
 
 	ctl1 = in_8(&regs->canctl1);
-	if (clock_src)
+	if (mscan_clksrc)
 		ctl1 |= MSCAN_CLKSRC;
 	else
 		ctl1 &= ~MSCAN_CLKSRC;
 
+	if (priv->type == MSCAN_TYPE_MPC5121)
+		ctl1 |= MSCAN_BORM; /* bus-off recovery upon request */
+
 	ctl1 |= MSCAN_CANE;
 	out_8(&regs->canctl1, ctl1);
 	udelay(100);