From: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>

Introduce FLEXCAN_QUIRK_IRQ_BERR quirk to handle hardware integration
where the FlexCAN module has a dedicated interrupt line for signaling
bus errors and device state changes.

This adds the flexcan_irq_esr() handler which composes
flexcan_do_state() and flexcan_do_berr() to handle platforms where
these events share a single IRQ line.

Also extend flexcan_chip_interrupts_enable() to disable/enable the
new IRQ line during IMASK register writes.

This is required for NXP S32N79 SoC support.

Co-developed-by: Larisa Grigore <larisa.grigore@nxp.com>
Signed-off-by: Larisa Grigore <larisa.grigore@nxp.com>
Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
---
 drivers/net/can/flexcan/flexcan-core.c | 54 +++++++++++++++++++++-----
 drivers/net/can/flexcan/flexcan.h      |  2 +
 2 files changed, 47 insertions(+), 9 deletions(-)

diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
index 32e4d4da00a1..23ddf7910641 100644
--- a/drivers/net/can/flexcan/flexcan-core.c
+++ b/drivers/net/can/flexcan/flexcan-core.c
@@ -1293,6 +1293,22 @@ static irqreturn_t flexcan_irq_boff(int irq, void *dev_id)
 	return handled;
 }
 
+/* Combined bus error and state change IRQ handler */
+static irqreturn_t flexcan_irq_esr(int irq, void *dev_id)
+{
+	struct net_device *dev = dev_id;
+	struct flexcan_priv *priv = netdev_priv(dev);
+	irqreturn_t handled;
+
+	handled = flexcan_do_state(dev);
+	handled |= flexcan_do_berr(dev);
+
+	if (handled)
+		can_rx_offload_irq_finish(&priv->offload);
+
+	return handled;
+}
+
 static void flexcan_set_bittiming_ctrl(const struct net_device *dev)
 {
 	const struct flexcan_priv *priv = netdev_priv(dev);
@@ -1549,10 +1565,10 @@ static void flexcan_chip_interrupts_enable(const struct net_device *dev)
 	u64 reg_imask;
 
 	disable_irq(dev->irq);
-	if (quirks & FLEXCAN_QUIRK_NR_IRQ_3) {
+	if (quirks & FLEXCAN_QUIRK_NR_IRQ_3)
 		disable_irq(priv->irq_boff);
+	if (quirks & (FLEXCAN_QUIRK_NR_IRQ_3 | FLEXCAN_QUIRK_IRQ_BERR))
 		disable_irq(priv->irq_err);
-	}
 	if (quirks & FLEXCAN_QUIRK_SECONDARY_MB_IRQ)
 		disable_irq(priv->irq_secondary_mb);
 
@@ -1564,10 +1580,10 @@ static void flexcan_chip_interrupts_enable(const struct net_device *dev)
 	enable_irq(dev->irq);
 	if (quirks & FLEXCAN_QUIRK_SECONDARY_MB_IRQ)
 		enable_irq(priv->irq_secondary_mb);
-	if (quirks & FLEXCAN_QUIRK_NR_IRQ_3) {
-		enable_irq(priv->irq_boff);
+	if (quirks & (FLEXCAN_QUIRK_NR_IRQ_3 | FLEXCAN_QUIRK_IRQ_BERR))
 		enable_irq(priv->irq_err);
-	}
+	if (quirks & FLEXCAN_QUIRK_NR_IRQ_3)
+		enable_irq(priv->irq_boff);
 }
 
 static void flexcan_chip_interrupts_disable(const struct net_device *dev)
@@ -1891,7 +1907,8 @@ static int flexcan_open(struct net_device *dev)
 
 	can_rx_offload_enable(&priv->offload);
 
-	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3)
+	if (priv->devtype_data.quirks &
+			(FLEXCAN_QUIRK_NR_IRQ_3 | FLEXCAN_QUIRK_IRQ_BERR))
 		err = request_irq(dev->irq, flexcan_irq_mb,
 				  IRQF_SHARED, dev->name, dev);
 	else
@@ -1912,6 +1929,13 @@ static int flexcan_open(struct net_device *dev)
 			goto out_free_irq_boff;
 	}
 
+	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_IRQ_BERR) {
+		err = request_irq(priv->irq_err,
+				  flexcan_irq_esr, IRQF_SHARED, dev->name, dev);
+		if (err)
+			goto out_free_irq_boff;
+	}
+
 	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SECONDARY_MB_IRQ) {
 		err = request_irq(priv->irq_secondary_mb,
 				  flexcan_irq_mb, IRQF_SHARED, dev->name, dev);
@@ -1926,7 +1950,8 @@ static int flexcan_open(struct net_device *dev)
 	return 0;
 
  out_free_irq_err:
-	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3)
+	if (priv->devtype_data.quirks &
+			(FLEXCAN_QUIRK_IRQ_BERR | FLEXCAN_QUIRK_NR_IRQ_3))
 		free_irq(priv->irq_err, dev);
  out_free_irq_boff:
 	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3)
@@ -1958,10 +1983,12 @@ static int flexcan_close(struct net_device *dev)
 	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SECONDARY_MB_IRQ)
 		free_irq(priv->irq_secondary_mb, dev);
 
-	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3) {
+	if (priv->devtype_data.quirks &
+			(FLEXCAN_QUIRK_IRQ_BERR | FLEXCAN_QUIRK_NR_IRQ_3))
 		free_irq(priv->irq_err, dev);
+
+	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3)
 		free_irq(priv->irq_boff, dev);
-	}
 
 	free_irq(dev->irq, dev);
 	can_rx_offload_disable(&priv->offload);
@@ -2348,12 +2375,21 @@ static int flexcan_probe(struct platform_device *pdev)
 	if (transceiver)
 		priv->can.bitrate_max = transceiver->attrs.max_link_rate;
 
+	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_IRQ_BERR) {
+		priv->irq_err = platform_get_irq_byname(pdev, "berr");
+		if (priv->irq_err < 0) {
+			err = priv->irq_err;
+			goto failed_platform_get_irq;
+		}
+	}
+
 	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3) {
 		priv->irq_boff = platform_get_irq(pdev, 1);
 		if (priv->irq_boff < 0) {
 			err = priv->irq_boff;
 			goto failed_platform_get_irq;
 		}
+
 		priv->irq_err = platform_get_irq(pdev, 2);
 		if (priv->irq_err < 0) {
 			err = priv->irq_err;
diff --git a/drivers/net/can/flexcan/flexcan.h b/drivers/net/can/flexcan/flexcan.h
index 22aa097ec3c0..43d4e0da3779 100644
--- a/drivers/net/can/flexcan/flexcan.h
+++ b/drivers/net/can/flexcan/flexcan.h
@@ -74,6 +74,8 @@
  * both need to have an interrupt handler registered.
  */
 #define FLEXCAN_QUIRK_SECONDARY_MB_IRQ	BIT(18)
+/* Setup dedicated bus error and state change IRQ */
+#define FLEXCAN_QUIRK_IRQ_BERR	BIT(19)
 
 #define FLEXCAN_NR_MB_IRQS	2
 
-- 
2.43.0