[PATCH v3 0/6] can: flexcan: Add NXP S32N79 SoC support

[PATCH v3 0/6] can: flexcan: Add NXP S32N79 SoC support

[Ciprian Costea]

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

This patch series adds FlexCAN support for the NXP S32N79 SoC.

The S32N79 is an automotive-grade processor from NXP with multiple
FlexCAN instances. The FlexCAN IP integration on S32N79 differs from
other SoCs in the interrupt routing - it uses two separate interrupt
lines:
  - one interrupt for mailboxes 0-127
  - one interrupt for bus error detection and device state changes

The CAN controllers are connected through an irqsteer interrupt
controller in the RCU (Resource Control Unit) domain.

This series:
  1. Splits flexcan_irq() into dedicated handlers for multi-IRQ platforms
  2. Adds dt-bindings documentation for S32N79 FlexCAN
  3. Introduces FLEXCAN_QUIRK_IRQ_BERR to handle the two-interrupt
     configuration
  4. Adds S32N79 device data and compatible string to the driver
  5. Adds FlexCAN device tree nodes for S32N79 SoC
  6. Enables FlexCAN devices on the S32N79-RDB board

Tested on S32N79-RDB board with CAN and CAN FD communication.

v3 -> v2
- Split flexcan_irq() into dedicated handlers (flexcan_irq_mb,
  flexcan_irq_boff, flexcan_irq_berr) to fix duplicate event
  processing when multiple IRQ lines run concurrently (new patch).
- Added flexcan_irq_esr() handler composing state + berr for S32N79
- Ordered quirks used by s32n devtype data by value.

v2 -> v1
- Renamed FLEXCAN_QUIRK_NR_IRQ_2 to FLEXCAN_QUIRK_IRQ_BERR to better
describe the actual hardware feature
- Appended new quirk at the end
- Switched from platform_get_irq to platform_get_irq_byname usage
- Updated interrupt description in dt-bindings


Ciprian Marian Costea (6):
  can: flexcan: use dedicated IRQ handlers for multi-IRQ platforms
  dt-bindings: can: fsl,flexcan: add NXP S32N79 SoC support
  can: flexcan: add FLEXCAN_QUIRK_IRQ_BERR quirk
  can: flexcan: add NXP S32N79 SoC support
  arm64: dts: s32n79: add FlexCAN nodes
  arm64: dts: s32n79: enable FlexCAN devices

 .../bindings/net/can/fsl,flexcan.yaml         |  30 ++-
 arch/arm64/boot/dts/freescale/s32n79-rdb.dts  |  12 ++
 arch/arm64/boot/dts/freescale/s32n79.dtsi     |  50 +++++
 drivers/net/can/flexcan/flexcan-core.c        | 180 ++++++++++++++++--
 drivers/net/can/flexcan/flexcan.h             |   2 +
 5 files changed, 253 insertions(+), 21 deletions(-)

-- 
2.43.0

[PATCH v3 1/6] can: flexcan: use dedicated IRQ handlers for multi-IRQ platforms

[Ciprian Costea]

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

On platforms with multiple IRQ lines (S32G2, MCF5441X), all lines are
registered to the same flexcan_irq() handler. Since these are distinct IRQ
numbers, they can be dispatched concurrently on different CPUs. Both
instances then read the same iflag and ESR registers unconditionally,
leading to duplicate frame processing.

Fix this by splitting the monolithic handler into focused parts:
- flexcan_do_mb(): processes mailbox events
- flexcan_do_state(): processes device state change events
- flexcan_do_berr(): processes bus error events

Introduce dedicated IRQ handlers for multi-IRQ platforms:
- flexcan_irq_mb(): mailbox-only, used for mb-0, mb-1 IRQ lines
- flexcan_irq_boff(): state-change-only, used for boff/state IRQ line
- flexcan_irq_berr(): bus-error-only, used for berr IRQ line

The combined flexcan_irq() handler is preserved for single-IRQ
platforms with no functional change.

Fixes: d9cead75b1c6 ("can: flexcan: add mcf5441x support")
Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
---
 drivers/net/can/flexcan/flexcan-core.c | 128 +++++++++++++++++++++----
 1 file changed, 111 insertions(+), 17 deletions(-)

diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
index f5d22c61503f..da712972d5de 100644
--- a/drivers/net/can/flexcan/flexcan-core.c
+++ b/drivers/net/can/flexcan/flexcan-core.c
@@ -1070,16 +1070,14 @@ static struct sk_buff *flexcan_mailbox_read(struct can_rx_offload *offload,
 	return skb;
 }
 
-static irqreturn_t flexcan_irq(int irq, void *dev_id)
+/* Process mailbox (RX + TX) events */
+static irqreturn_t flexcan_do_mb(struct net_device *dev)
 {
-	struct net_device *dev = dev_id;
 	struct net_device_stats *stats = &dev->stats;
 	struct flexcan_priv *priv = netdev_priv(dev);
 	struct flexcan_regs __iomem *regs = priv->regs;
 	irqreturn_t handled = IRQ_NONE;
 	u64 reg_iflag_tx;
-	u32 reg_esr;
-	enum can_state last_state = priv->can.state;
 
 	/* reception interrupt */
 	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_USE_RX_MAILBOX) {
@@ -1131,25 +1129,57 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id)
 		netif_wake_queue(dev);
 	}
 
+	return handled;
+}
+
+/* Process bus error events */
+static irqreturn_t flexcan_do_berr(struct net_device *dev)
+{
+	struct flexcan_priv *priv = netdev_priv(dev);
+	struct flexcan_regs __iomem *regs = priv->regs;
+	irqreturn_t handled = IRQ_NONE;
+	u32 reg_esr;
+
 	reg_esr = priv->read(&regs->esr);
 
-	/* ACK all bus error, state change and wake IRQ sources */
-	if (reg_esr & (FLEXCAN_ESR_ALL_INT | FLEXCAN_ESR_WAK_INT)) {
+	/* ACK bus error interrupt source */
+	if (reg_esr & (FLEXCAN_ESR_ERR_INT)) {
 		handled = IRQ_HANDLED;
-		priv->write(reg_esr & (FLEXCAN_ESR_ALL_INT | FLEXCAN_ESR_WAK_INT), &regs->esr);
+		priv->write(FLEXCAN_ESR_ERR_INT, &regs->esr);
 	}
 
-	/* state change interrupt or broken error state quirk fix is enabled */
-	if ((reg_esr & FLEXCAN_ESR_ERR_STATE) ||
-	    (priv->devtype_data.quirks & (FLEXCAN_QUIRK_BROKEN_WERR_STATE |
-					   FLEXCAN_QUIRK_BROKEN_PERR_STATE)))
-		flexcan_irq_state(dev, reg_esr);
-
 	/* bus error IRQ - handle if bus error reporting is activated */
 	if ((reg_esr & FLEXCAN_ESR_ERR_BUS) &&
 	    (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING))
 		flexcan_irq_bus_err(dev, reg_esr);
 
+	return handled;
+}
+
+/* Process device state change events */
+static irqreturn_t flexcan_do_state(struct net_device *dev)
+{
+	struct flexcan_priv *priv = netdev_priv(dev);
+	struct flexcan_regs __iomem *regs = priv->regs;
+	irqreturn_t handled = IRQ_NONE;
+	u32 reg_esr;
+	enum can_state last_state = priv->can.state;
+
+	reg_esr = priv->read(&regs->esr);
+
+	/* ACK state change and wake IRQ sources */
+	if (reg_esr & (FLEXCAN_ESR_ERR_STATE | FLEXCAN_ESR_WAK_INT)) {
+		handled = IRQ_HANDLED;
+		priv->write(reg_esr & (FLEXCAN_ESR_ERR_STATE | FLEXCAN_ESR_WAK_INT),
+				&regs->esr);
+	}
+
+	/* state change interrupt or broken error state quirk fix is enabled */
+	if ((reg_esr & FLEXCAN_ESR_ERR_STATE) ||
+	    (priv->devtype_data.quirks &
+	    (FLEXCAN_QUIRK_BROKEN_WERR_STATE | FLEXCAN_QUIRK_BROKEN_PERR_STATE)))
+		flexcan_irq_state(dev, reg_esr);
+
 	/* availability of error interrupt among state transitions in case
 	 * bus error reporting is de-activated and
 	 * FLEXCAN_QUIRK_BROKEN_PERR_STATE is enabled:
@@ -1188,6 +1218,65 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id)
 		}
 	}
 
+	return handled;
+}
+
+/* Combined IRQ handler for single-IRQ platforms */
+static irqreturn_t flexcan_irq(int irq, void *dev_id)
+{
+	struct net_device *dev = dev_id;
+	struct flexcan_priv *priv = netdev_priv(dev);
+	irqreturn_t handled;
+
+	handled = flexcan_do_mb(dev);
+	handled |= flexcan_do_state(dev);
+	handled |= flexcan_do_berr(dev);
+
+	if (handled)
+		can_rx_offload_irq_finish(&priv->offload);
+
+	return handled;
+}
+
+/* Mailbox IRQ handler for multi-IRQ platforms */
+static irqreturn_t flexcan_irq_mb(int irq, void *dev_id)
+{
+	struct net_device *dev = dev_id;
+	struct flexcan_priv *priv = netdev_priv(dev);
+	irqreturn_t handled;
+
+	handled = flexcan_do_mb(dev);
+
+	if (handled)
+		can_rx_offload_irq_finish(&priv->offload);
+
+	return handled;
+}
+
+/* Bus error IRQ handler for multi-IRQ platforms */
+static irqreturn_t flexcan_irq_berr(int irq, void *dev_id)
+{
+	struct net_device *dev = dev_id;
+	struct flexcan_priv *priv = netdev_priv(dev);
+	irqreturn_t handled;
+
+	handled = flexcan_do_berr(dev);
+
+	if (handled)
+		can_rx_offload_irq_finish(&priv->offload);
+
+	return handled;
+}
+
+/* Device state change IRQ handler for multi-IRQ platforms */
+static irqreturn_t flexcan_irq_boff(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);
+
 	if (handled)
 		can_rx_offload_irq_finish(&priv->offload);
 
@@ -1761,25 +1850,30 @@ static int flexcan_open(struct net_device *dev)
 
 	can_rx_offload_enable(&priv->offload);
 
-	err = request_irq(dev->irq, flexcan_irq, IRQF_SHARED, dev->name, dev);
+	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3)
+		err = request_irq(dev->irq, flexcan_irq_mb,
+				  IRQF_SHARED, dev->name, dev);
+	else
+		err = request_irq(dev->irq, flexcan_irq,
+				  IRQF_SHARED, dev->name, dev);
 	if (err)
 		goto out_can_rx_offload_disable;
 
 	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3) {
 		err = request_irq(priv->irq_boff,
-				  flexcan_irq, IRQF_SHARED, dev->name, dev);
+				  flexcan_irq_boff, IRQF_SHARED, dev->name, dev);
 		if (err)
 			goto out_free_irq;
 
 		err = request_irq(priv->irq_err,
-				  flexcan_irq, IRQF_SHARED, dev->name, dev);
+				  flexcan_irq_berr, 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, IRQF_SHARED, dev->name, dev);
+				  flexcan_irq_mb, IRQF_SHARED, dev->name, dev);
 		if (err)
 			goto out_free_irq_err;
 	}
-- 
2.43.0

Re: [PATCH v3 1/6] can: flexcan: use dedicated IRQ handlers for multi-IRQ platforms

[Marc Kleine-Budde]

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On 23.03.2026 14:58:22, Ciprian Costea wrote:
> From: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
>
> On platforms with multiple IRQ lines (S32G2, MCF5441X), all lines are
> registered to the same flexcan_irq() handler. Since these are distinct IRQ
> numbers, they can be dispatched concurrently on different CPUs. Both
> instances then read the same iflag and ESR registers unconditionally,
> leading to duplicate frame processing.
>
> Fix this by splitting the monolithic handler into focused parts:
> - flexcan_do_mb(): processes mailbox events
> - flexcan_do_state(): processes device state change events
> - flexcan_do_berr(): processes bus error events
>
> Introduce dedicated IRQ handlers for multi-IRQ platforms:
> - flexcan_irq_mb(): mailbox-only, used for mb-0, mb-1 IRQ lines
> - flexcan_irq_boff(): state-change-only, used for boff/state IRQ line
> - flexcan_irq_berr(): bus-error-only, used for berr IRQ line
>
> The combined flexcan_irq() handler is preserved for single-IRQ
> platforms with no functional change.

Thanks for implementing this.

Can you take care of the S32G2 which has 2 mailbox IRQs, too? Please in
a separate patch.

My idea was to take the "irq" argument of the IRQ handler and the quirks
and figure out if you are the first or second mailbox IRQ handler.

Convert these

| struct flexcan_priv {
| [...]
| 	u64 rx_mask;
| 	u64 tx_mask;
| [...]
| }

into a struct and put an array of 2 of these structs into "struct
flexcan_priv". Use correct mask array depending on IRQ handler.

regards,
Marc

--
Pengutronix e.K.                 | Marc Kleine-Budde          |
Embedded Linux                   | https://www.pengutronix.de |
Vertretung Nürnberg              | Phone: +49-5121-206917-129 |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-9   |

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Re: [PATCH v3 1/6] can: flexcan: use dedicated IRQ handlers for multi-IRQ platforms

[Ciprian Marian Costea]

On 3/24/2026 1:56 PM, Marc Kleine-Budde wrote:
> On 23.03.2026 14:58:22, Ciprian Costea wrote:
>> From: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
>>
>> On platforms with multiple IRQ lines (S32G2, MCF5441X), all lines are
>> registered to the same flexcan_irq() handler. Since these are distinct IRQ
>> numbers, they can be dispatched concurrently on different CPUs. Both
>> instances then read the same iflag and ESR registers unconditionally,
>> leading to duplicate frame processing.
>>
>> Fix this by splitting the monolithic handler into focused parts:
>> - flexcan_do_mb(): processes mailbox events
>> - flexcan_do_state(): processes device state change events
>> - flexcan_do_berr(): processes bus error events
>>
>> Introduce dedicated IRQ handlers for multi-IRQ platforms:
>> - flexcan_irq_mb(): mailbox-only, used for mb-0, mb-1 IRQ lines
>> - flexcan_irq_boff(): state-change-only, used for boff/state IRQ line
>> - flexcan_irq_berr(): bus-error-only, used for berr IRQ line
>>
>> The combined flexcan_irq() handler is preserved for single-IRQ
>> platforms with no functional change.
> 
> Thanks for implementing this.
> 
> Can you take care of the S32G2 which has 2 mailbox IRQs, too? Please in
> a separate patch.
> 
> My idea was to take the "irq" argument of the IRQ handler and the quirks
> and figure out if you are the first or second mailbox IRQ handler.
> 
> Convert these
> 
> | struct flexcan_priv {
> | [...]
> | 	u64 rx_mask;
> | 	u64 tx_mask;
> | [...]
> | }
> 
> into a struct and put an array of 2 of these structs into "struct
> flexcan_priv". Use correct mask array depending on IRQ handler.
> 
> regards,
> Marc
> 
> --
> Pengutronix e.K.                 | Marc Kleine-Budde          |
> Embedded Linux                   | https://www.pengutronix.de |
> Vertretung Nürnberg              | Phone: +49-5121-206917-129 |
> Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-9   |

Hello Marc,

Thanks for your review.
I'll add a separate patch implementing per-MB-IRQ mask handling (needed
by S32G2) in V4. And thanks for the implementation suggestion. I'll take
it into account.

Now, unrelated to the per-MB-IRQ refactor, one thing I noticed during 
the IRQ handlers split: dev->stats counters (e.g. rx_fifo_errors) can
be incremented concurrently from different IRQ handlers on different CPUs.

That said, these are just diagnostic counters and lost increments
should be benign. Do you think this warrants any synchronization/locking 
mechanism, or is the current behavior acceptable?

Regards,
Ciprian

Re: [PATCH v3 1/6] can: flexcan: use dedicated IRQ handlers for multi-IRQ platforms

[Marc Kleine-Budde]

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On 24.03.2026 14:30:50, Ciprian Marian Costea wrote:
> > Can you take care of the S32G2 which has 2 mailbox IRQs, too? Please in
> > a separate patch.
> >
> > My idea was to take the "irq" argument of the IRQ handler and the quirks
> > and figure out if you are the first or second mailbox IRQ handler.
> >
> > Convert these
> >
> > | struct flexcan_priv {
> > | [...]
> > | 	u64 rx_mask;
> > | 	u64 tx_mask;
> > | [...]
> > | }
> >
> > into a struct and put an array of 2 of these structs into "struct
> > flexcan_priv". Use correct mask array depending on IRQ handler.
> >
> > regards,
> > Marc
> >
> > --
> > Pengutronix e.K.                 | Marc Kleine-Budde          |
> > Embedded Linux                   | https://www.pengutronix.de |
> > Vertretung Nürnberg              | Phone: +49-5121-206917-129 |
> > Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-9   |
>
> Thanks for your review.
> I'll add a separate patch implementing per-MB-IRQ mask handling (needed
> by S32G2) in V4. And thanks for the implementation suggestion. I'll take
> it into account.

Maybe you can come up with a improved/better solution.

With the potential concurrent mailbox IRQ handlers on the s32g we have a
problem with the rx-offload infrastructure. After converting it to
per-CPU lists, we still have to merge the lists to the global one.

The current supported use case is a single IRQ handler that adds all
received CAN frames (and CAN error frames) sorted to the skb_irq_queue
list. At the end of the IRQ handler the list is appended to the
skb_queue and NAPI pushes the CAN frames into the networking stack.

This is done to preserve the order of CAN frames, which is crucial for
some CAN protocols.

If we have 2 IRQ handlers adding the per-cpu skb_irq_queue to the
skb_queue might lead to out-of-order reception.

I see 2 options to workaround this:
- Lock the skb_queue and sort each packet into it.
  This makes the lock longer and
  if an IRQ is delayed old packets might already been processed, so
  out-of-order reception is still possible.
- Disable mailboxes 1...8 for the s32g and only use the 2nd IRQ handler.
  This obviously reduces the number of RX mailboxes, this increases the
  change of RX buffer overflows on systems under high load.
  On the other hand the driver can be extended to use the mailboxes
  64...127.

As I don't have a s32g SoC nor a customer using it, I have no time to
implement this. Maybe you or someone from NXP is willing to do this.

> Now, unrelated to the per-MB-IRQ refactor, one thing I noticed during the
> IRQ handlers split: dev->stats counters (e.g. rx_fifo_errors) can
> be incremented concurrently from different IRQ handlers on different CPUs.
>
> That said, these are just diagnostic counters and lost increments
> should be benign. Do you think this warrants any synchronization/locking
> mechanism, or is the current behavior acceptable?

There are better ways to do stats, but IMHO for now we can live with the
problem.

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde          |
Embedded Linux                   | https://www.pengutronix.de |
Vertretung Nürnberg              | Phone: +49-5121-206917-129 |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-9   |

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[PATCH v3 2/6] dt-bindings: can: fsl,flexcan: add NXP S32N79 SoC support

[Ciprian Costea]

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

Add NXP S32N79 SoC compatible string and interrupt properties.

On S32N79, FlexCAN IP is integrated with two interrupt lines:
one for the mailbox interrupts (0-127) and one for signaling
bus errors and device state changes.

Co-developed-by: Andra-Teodora Ilie <andra.ilie@nxp.com>
Signed-off-by: Andra-Teodora Ilie <andra.ilie@nxp.com>
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>
---
 .../bindings/net/can/fsl,flexcan.yaml         | 30 ++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/net/can/fsl,flexcan.yaml b/Documentation/devicetree/bindings/net/can/fsl,flexcan.yaml
index f81d56f7c12a..d098a44c2b9c 100644
--- a/Documentation/devicetree/bindings/net/can/fsl,flexcan.yaml
+++ b/Documentation/devicetree/bindings/net/can/fsl,flexcan.yaml
@@ -26,6 +26,7 @@ properties:
           - fsl,ls1021ar2-flexcan
           - fsl,lx2160ar1-flexcan
           - nxp,s32g2-flexcan
+          - nxp,s32n79-flexcan
       - items:
           - enum:
               - fsl,imx53-flexcan
@@ -173,11 +174,38 @@ allOf:
             - const: mb-1
       required:
         - interrupt-names
-    else:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: nxp,s32n79-flexcan
+    then:
+      properties:
+        interrupts:
+          items:
+            - description: Message Buffer interrupt for mailboxes 0-127
+            - description: Bus Error and Device state change interrupt
+        interrupt-names:
+          items:
+            - const: mb-0
+            - const: berr
+      required:
+        - interrupt-names
+
+  - if:
+      not:
+        properties:
+          compatible:
+            contains:
+              enum:
+                - nxp,s32g2-flexcan
+                - nxp,s32n79-flexcan
+    then:
       properties:
         interrupts:
           maxItems: 1
         interrupt-names: false
+
   - if:
       required:
         - xceiver-supply
-- 
2.43.0

Re: [PATCH v3 2/6] dt-bindings: can: fsl,flexcan: add NXP S32N79 SoC support

[Conor Dooley]

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Acked-by: Conor Dooley <conor.dooley@microchip.com>
pw-bot: not-applicable

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[PATCH v3 3/6] can: flexcan: add FLEXCAN_QUIRK_IRQ_BERR quirk

[Ciprian Costea]

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.

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 | 44 +++++++++++++++++++++++---
 drivers/net/can/flexcan/flexcan.h      |  2 ++
 2 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
index da712972d5de..51f60bbf25fa 100644
--- a/drivers/net/can/flexcan/flexcan-core.c
+++ b/drivers/net/can/flexcan/flexcan-core.c
@@ -1283,6 +1283,22 @@ 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);
@@ -1850,7 +1866,8 @@ 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
@@ -1871,6 +1888,13 @@ 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);
@@ -1885,7 +1909,8 @@ 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)
@@ -1917,10 +1942,12 @@ 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);
@@ -2307,12 +2334,21 @@ 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 16692a2502eb..bbb1a8dd4777 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)
 
 struct flexcan_devtype_data {
 	u32 quirks;		/* quirks needed for different IP cores */
-- 
2.43.0

[PATCH v3 4/6] can: flexcan: add NXP S32N79 SoC support

[Ciprian Costea]

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

Add device data and compatible string for NXP S32N79 SoC.

FlexCAN IP integration on S32N79 SoC uses two interrupts:
- one for mailboxes 0-127
- one for signaling bus errors and device state changes

Co-developed-by: Andra-Teodora Ilie <andra.ilie@nxp.com>
Signed-off-by: Andra-Teodora Ilie <andra.ilie@nxp.com>
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 | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
index 51f60bbf25fa..3b7913fddc2c 100644
--- a/drivers/net/can/flexcan/flexcan-core.c
+++ b/drivers/net/can/flexcan/flexcan-core.c
@@ -397,6 +397,15 @@ static const struct flexcan_devtype_data nxp_s32g2_devtype_data = {
 		FLEXCAN_QUIRK_SECONDARY_MB_IRQ,
 };
 
+static const struct flexcan_devtype_data nxp_s32n_devtype_data = {
+	.quirks = FLEXCAN_QUIRK_DISABLE_RXFG | FLEXCAN_QUIRK_ENABLE_EACEN_RRS |
+		FLEXCAN_QUIRK_DISABLE_MECR | FLEXCAN_QUIRK_USE_RX_MAILBOX |
+		FLEXCAN_QUIRK_BROKEN_PERR_STATE | FLEXCAN_QUIRK_SUPPORT_FD |
+		FLEXCAN_QUIRK_SUPPORT_ECC | FLEXCAN_QUIRK_SUPPORT_RX_MAILBOX |
+		FLEXCAN_QUIRK_SUPPORT_RX_MAILBOX_RTR |
+		FLEXCAN_QUIRK_IRQ_BERR,
+};
+
 static const struct can_bittiming_const flexcan_bittiming_const = {
 	.name = DRV_NAME,
 	.tseg1_min = 4,
@@ -2191,6 +2200,7 @@ static const struct of_device_id flexcan_of_match[] = {
 	{ .compatible = "fsl,ls1021ar2-flexcan", .data = &fsl_ls1021a_r2_devtype_data, },
 	{ .compatible = "fsl,lx2160ar1-flexcan", .data = &fsl_lx2160a_r1_devtype_data, },
 	{ .compatible = "nxp,s32g2-flexcan", .data = &nxp_s32g2_devtype_data, },
+	{ .compatible = "nxp,s32n79-flexcan", .data = &nxp_s32n_devtype_data, },
 	{ /* sentinel */ },
 };
 MODULE_DEVICE_TABLE(of, flexcan_of_match);
-- 
2.43.0

[PATCH v3 5/6] arm64: dts: s32n79: add FlexCAN nodes

[Ciprian Costea]

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

The S32N79 integrates multiple FlexCAN instances connected through the RCU
irqsteer interrupt controller.

Co-developed-by: Andra-Teodora Ilie <andra.ilie@nxp.com>
Signed-off-by: Andra-Teodora Ilie <andra.ilie@nxp.com>
Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
---
 arch/arm64/boot/dts/freescale/s32n79.dtsi | 50 +++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/s32n79.dtsi b/arch/arm64/boot/dts/freescale/s32n79.dtsi
index 94ab58783fdc..c1a4fdead91d 100644
--- a/arch/arm64/boot/dts/freescale/s32n79.dtsi
+++ b/arch/arm64/boot/dts/freescale/s32n79.dtsi
@@ -352,6 +352,56 @@ pmu: pmu {
 		interrupts = <GIC_PPI 7 IRQ_TYPE_LEVEL_HIGH>;
 	};
 
+	rcu-bus {
+		compatible = "simple-bus";
+		ranges = <0x54000000 0x0 0x54000000 0x4000000>;
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		irqsteer_rcu: interrupt-controller@55101000 {
+			compatible = "nxp,s32n79-irqsteer";
+			reg = <0x55101000 0x1000>;
+			#interrupt-cells = <1>;
+			interrupt-controller;
+			interrupt-parent = <&gic>;
+			interrupts = <GIC_SPI 73 IRQ_TYPE_LEVEL_HIGH>,
+				<GIC_SPI 74 IRQ_TYPE_LEVEL_HIGH>,
+				<GIC_SPI 75 IRQ_TYPE_LEVEL_HIGH>,
+				<GIC_SPI 76 IRQ_TYPE_LEVEL_HIGH>,
+				<GIC_SPI 77 IRQ_TYPE_LEVEL_HIGH>,
+				<GIC_SPI 78 IRQ_TYPE_LEVEL_HIGH>,
+				<GIC_SPI 79 IRQ_TYPE_LEVEL_HIGH>,
+				<GIC_SPI 80 IRQ_TYPE_LEVEL_HIGH>;
+			clocks = <&clks 0xf9>;
+			clock-names = "ipg";
+			fsl,channel = <0>;
+			fsl,num-irqs = <512>;
+			status = "disabled";
+		};
+
+		can0: can@55b60000 {
+			compatible = "nxp,s32n79-flexcan";
+			reg = <0x55b60000 0x4000>;
+			interrupt-parent = <&irqsteer_rcu>;
+			interrupts = <0>, <64>;
+			interrupt-names = "mb-0", "berr";
+			clocks = <&clks 0xf9>, <&clks 0xfc>;
+			clock-names = "ipg", "per";
+			status = "disabled";
+		};
+
+		can1: can@55b70000 {
+			compatible = "nxp,s32n79-flexcan";
+			reg = <0x55b70000 0x4000>;
+			interrupt-parent = <&irqsteer_rcu>;
+			interrupts = <1>, <65>;
+			interrupt-names = "mb-0", "berr";
+			clocks = <&clks 0xf9>, <&clks 0xfc>;
+			clock-names = "ipg", "per";
+			status = "disabled";
+		};
+	};
+
 	timer: timer {
 		compatible = "arm,armv8-timer";
 		interrupts = <GIC_PPI 13 IRQ_TYPE_LEVEL_LOW>,
-- 
2.43.0

[PATCH v3 6/6] arm64: dts: s32n79: enable FlexCAN devices

[Ciprian Costea]

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

Enable FlexCAN controller instances (can0 and can1) and the required RCU
irqsteer interrupt controller on S32N79-RDB board.

Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
---
 arch/arm64/boot/dts/freescale/s32n79-rdb.dts | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/s32n79-rdb.dts b/arch/arm64/boot/dts/freescale/s32n79-rdb.dts
index 1feccd61258e..65a595d7535f 100644
--- a/arch/arm64/boot/dts/freescale/s32n79-rdb.dts
+++ b/arch/arm64/boot/dts/freescale/s32n79-rdb.dts
@@ -43,10 +43,22 @@ memory@80000000 {
 	};
 };
 
+&can0 {
+	status = "okay";
+};
+
+&can1 {
+	status = "okay";
+};
+
 &irqsteer_coss {
 	status = "okay";
 };
 
+&irqsteer_rcu {
+	status = "okay";
+};
+
 &uart0 {
 	status = "okay";
 };
-- 
2.43.0

Re: [PATCH v3 0/6] can: flexcan: Add NXP S32N79 SoC support

[Marc Kleine-Budde]

[-- Attachment #1: Type: text/plain, Size: 1443 bytes --]

On 23.03.2026 14:58:21, Ciprian Costea wrote:
> From: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
>
> This patch series adds FlexCAN support for the NXP S32N79 SoC.
>
> The S32N79 is an automotive-grade processor from NXP with multiple
> FlexCAN instances. The FlexCAN IP integration on S32N79 differs from
> other SoCs in the interrupt routing - it uses two separate interrupt
> lines:
>   - one interrupt for mailboxes 0-127
>   - one interrupt for bus error detection and device state changes
>
> The CAN controllers are connected through an irqsteer interrupt
> controller in the RCU (Resource Control Unit) domain.
>
> This series:
>   1. Splits flexcan_irq() into dedicated handlers for multi-IRQ platforms
>   2. Adds dt-bindings documentation for S32N79 FlexCAN
>   3. Introduces FLEXCAN_QUIRK_IRQ_BERR to handle the two-interrupt
>      configuration
>   4. Adds S32N79 device data and compatible string to the driver
>   5. Adds FlexCAN device tree nodes for S32N79 SoC
>   6. Enables FlexCAN devices on the S32N79-RDB board

Can you please add support for multiple IRQs to
flexcan_chip_interrupts_enable().

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde          |
Embedded Linux                   | https://www.pengutronix.de |
Vertretung Nürnberg              | Phone: +49-5121-206917-129 |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-9   |

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Re: [PATCH v3 0/6] can: flexcan: Add NXP S32N79 SoC support

[Ciprian Marian Costea]

On 3/24/2026 1:58 PM, Marc Kleine-Budde wrote:
> On 23.03.2026 14:58:21, Ciprian Costea wrote:
>> From: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
>>
>> This patch series adds FlexCAN support for the NXP S32N79 SoC.
>>
>> The S32N79 is an automotive-grade processor from NXP with multiple
>> FlexCAN instances. The FlexCAN IP integration on S32N79 differs from
>> other SoCs in the interrupt routing - it uses two separate interrupt
>> lines:
>>    - one interrupt for mailboxes 0-127
>>    - one interrupt for bus error detection and device state changes
>>
>> The CAN controllers are connected through an irqsteer interrupt
>> controller in the RCU (Resource Control Unit) domain.
>>
>> This series:
>>    1. Splits flexcan_irq() into dedicated handlers for multi-IRQ platforms
>>    2. Adds dt-bindings documentation for S32N79 FlexCAN
>>    3. Introduces FLEXCAN_QUIRK_IRQ_BERR to handle the two-interrupt
>>       configuration
>>    4. Adds S32N79 device data and compatible string to the driver
>>    5. Adds FlexCAN device tree nodes for S32N79 SoC
>>    6. Enables FlexCAN devices on the S32N79-RDB board
> 
> Can you please add support for multiple IRQs to
> flexcan_chip_interrupts_enable().
> 
> regards,
> Marc
> 

Hello Marc,

Yes. Thanks for pointing this out. I will update 
flexcan_chip_interrupts_enable() in V4.

Regards,
Ciprian

Re: [PATCH v3 0/6] can: flexcan: Add NXP S32N79 SoC support

[Marc Kleine-Budde]

[-- Attachment #1: Type: text/plain, Size: 1066 bytes --]

On 23.03.2026 14:58:21, Ciprian Costea wrote:
> From: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
>
> This patch series adds FlexCAN support for the NXP S32N79 SoC.
>
> The S32N79 is an automotive-grade processor from NXP with multiple
> FlexCAN instances. The FlexCAN IP integration on S32N79 differs from
> other SoCs in the interrupt routing - it uses two separate interrupt
> lines:
>   - one interrupt for mailboxes 0-127
>   - one interrupt for bus error detection and device state changes

Can you check if the S32N79 suffers from the

| /* No interrupt for error passive */
| #define FLEXCAN_QUIRK_BROKEN_PERR_STATE BIT(6)

problem? Maybe everyone just added the FLEXCAN_QUIRK_BROKEN_PERR_STATE
for the new SoC without actually testing it.

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde          |
Embedded Linux                   | https://www.pengutronix.de |
Vertretung Nürnberg              | Phone: +49-5121-206917-129 |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-9   |

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Re: [PATCH v3 0/6] can: flexcan: Add NXP S32N79 SoC support

[Ciprian Marian Costea]

On 3/24/2026 3:46 PM, Marc Kleine-Budde wrote:
> On 23.03.2026 14:58:21, Ciprian Costea wrote:
>> From: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
>>
>> This patch series adds FlexCAN support for the NXP S32N79 SoC.
>>
>> The S32N79 is an automotive-grade processor from NXP with multiple
>> FlexCAN instances. The FlexCAN IP integration on S32N79 differs from
>> other SoCs in the interrupt routing - it uses two separate interrupt
>> lines:
>>    - one interrupt for mailboxes 0-127
>>    - one interrupt for bus error detection and device state changes
> 
> Can you check if the S32N79 suffers from the
> 
> | /* No interrupt for error passive */
> | #define FLEXCAN_QUIRK_BROKEN_PERR_STATE BIT(6)
> 
> problem? Maybe everyone just added the FLEXCAN_QUIRK_BROKEN_PERR_STATE
> for the new SoC without actually testing it.
> 
> regards,
> Marc
> 

Hello Marc,

I've tested on S32N79 hardware. Without the quirk, the controller
reaches Transmit-Error-Counter=128 (error-passive at HW level) but the
driver only sees ERROR-WARNING - the passive interrupt never fires.

With the quirk enabled, ERROR-PASSIVE is correctly reported.
So FLEXCAN_QUIRK_BROKEN_PERR_STATE quirk is needed for S32N79.

Best Regards,
Ciprian