[PATCH v5 0/8] can: flexcan: Add NXP S32N79 SoC support

[PATCH v5 0/8] 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.

v5 -> v4
- Simplified splitting rx/tx masks per mailbox IRQ line

v4 -> v3
- flexcan_chip_interrupts_enable(): disable/enable all IRQ lines
  (not just dev->irq) during IMASK register writes
- Split rx/tx masks per mailbox IRQ line (struct flexcan_mb_irq) so
  each handler on S32G2 only processes its own MB range
- Added received Acked-by tag on DT bindings patch

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 (8):
  can: flexcan: use dedicated IRQ handlers for multi-IRQ platforms
  can: flexcan: disable all IRQ lines in
    flexcan_chip_interrupts_enable()
  can: flexcan: split rx/tx masks per mailbox IRQ line
  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        | 227 +++++++++++++++---
 drivers/net/can/flexcan/flexcan.h             |   2 +
 5 files changed, 292 insertions(+), 29 deletions(-)

-- 
2.43.0

[PATCH v5 1/8] 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>
Reviewed-and-tested-by: Haibo Chen <haibo.chen@nxp.com>
Tested-by: Enric Balletbo i Serra <eballetb@redhat.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..f73ff442d530 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 v5 1/8] can: flexcan: use dedicated IRQ handlers for multi-IRQ platforms

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:

New issues:
- [High] Splitting the IRQ handlers breaks `FLEXCAN_QUIRK_BROKEN_PERR_STATE` polling and strands state change SKBs.

Pre-existing issues:
- [Critical] Concurrent execution of split IRQ handlers corrupts the lockless CAN `rx_offload` queue.
--

commit bffb52105dbcdcc01b5331e294239af017d43aeb
Author: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>

can: flexcan: use dedicated IRQ handlers for multi-IRQ platforms

This patch splits the monolithic flexcan IRQ handler into focused parts
and introduces dedicated IRQ handlers for multi-IRQ platforms to prevent
duplicate frame processing.

> diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
> index f5d22c61503fa..f73ff442d5304 100644
> --- a/drivers/net/can/flexcan/flexcan-core.c
> +++ b/drivers/net/can/flexcan/flexcan-core.c
> @@ -1188,6 +1218,65 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id)
[ ... ]
> +/* 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);

[Severity: High]
By splitting the handler, does this break the FLEXCAN_QUIRK_BROKEN_PERR_STATE
polling mechanism? Before this patch, the monolithic flexcan_irq() naturally
polled flexcan_do_state() during mailbox interrupts. Now that flexcan_irq_mb()
bypasses flexcan_do_state(), it seems state transitions might no longer be
polled during active CAN traffic.

> +
> +	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);

[Severity: Critical]
This is a pre-existing issue, but does assigning dedicated handlers to
different IRQ lines lead to concurrent modifications of the lockless
rx_offload queue?

Since flexcan_irq_mb() and flexcan_irq_berr() can run concurrently on
different CPUs, flexcan_do_mb() and flexcan_do_berr() might concurrently
call can_rx_offload_queue_timestamp().

That function uses __skb_queue_add_sort(), which is a lockless primitive
that assumes strictly serialized execution. Could this lead to doubly-linked
list corruption and kernel panics, further exacerbated by concurrent unlocked
splices in can_rx_offload_irq_finish()?

> +
> +	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);

[Severity: High]
If flexcan_do_state() queues an SKB but returns IRQ_NONE (e.g., if no ESR
bits are set), will this skip the can_rx_offload_irq_finish() call and
strand the state change SKB in the lockless queue?

> +
> +	return handled;
> +}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260609142954.1807421-1-ciprianmarian.costea@oss.nxp.com?part=1

Re: [PATCH v5 1/8] can: flexcan: use dedicated IRQ handlers for multi-IRQ platforms

[Vincent Mailhol]

On 09/06/2026 at 16:29, 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.
> 
> Fixes: d9cead75b1c6 ("can: flexcan: add mcf5441x support")
> Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
> Reviewed-and-tested-by: Haibo Chen <haibo.chen@nxp.com>
> Tested-by: Enric Balletbo i Serra <eballetb@redhat.com>

Reviewed-by: Vincent Mailhol <mailhol@kernel.org>


Yours sincerely,
Vincent Mailhol

[PATCH v5 2/8] can: flexcan: disable all IRQ lines in flexcan_chip_interrupts_enable()

[Ciprian Costea]

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

flexcan_chip_interrupts_enable() disables only the primary IRQ line while
writing to the IMASK and CTRL registers.

On multi-IRQ platforms (S32G2, MCF5441X), the additional IRQ lines (boff,
err, secondary-mb) remain active so their handlers can fire while
registers are inconsistent.

Disable all registered IRQ lines around the IMASK/CTRL writes. This
also fixes the resume path, which calls this function.

Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
Reviewed-and-tested-by: Haibo Chen <haibo.chen@nxp.com>
Tested-by: Enric Balletbo i Serra <eballetb@redhat.com>
---
 drivers/net/can/flexcan/flexcan-core.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
index f73ff442d530..7dde2e623def 100644
--- a/drivers/net/can/flexcan/flexcan-core.c
+++ b/drivers/net/can/flexcan/flexcan-core.c
@@ -1519,14 +1519,28 @@ static void flexcan_chip_interrupts_enable(const struct net_device *dev)
 {
 	const struct flexcan_priv *priv = netdev_priv(dev);
 	struct flexcan_regs __iomem *regs = priv->regs;
+	u32 quirks = priv->devtype_data.quirks;
 	u64 reg_imask;
 
 	disable_irq(dev->irq);
+	if (quirks & FLEXCAN_QUIRK_NR_IRQ_3) {
+		disable_irq(priv->irq_boff);
+		disable_irq(priv->irq_err);
+	}
+	if (quirks & FLEXCAN_QUIRK_SECONDARY_MB_IRQ)
+		disable_irq(priv->irq_secondary_mb);
+
 	priv->write(priv->reg_ctrl_default, &regs->ctrl);
 	reg_imask = priv->rx_mask | priv->tx_mask;
 	priv->write(upper_32_bits(reg_imask), &regs->imask2);
 	priv->write(lower_32_bits(reg_imask), &regs->imask1);
 	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);
+		enable_irq(priv->irq_err);
+	}
 }
 
 static void flexcan_chip_interrupts_disable(const struct net_device *dev)
-- 
2.43.0

Re: [PATCH v5 2/8] can: flexcan: disable all IRQ lines in flexcan_chip_interrupts_enable()

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] The bus-off recovery worker (`can_restart_work`) can execute concurrently with the hardware teardown in `flexcan_close()`, leading to an unhandled interrupt storm on a shared IRQ line.
--

commit fd331d38665dbbf68f2818faa72e3515deb0d5b3
Author: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>

can: flexcan: disable all IRQ lines in flexcan_chip_interrupts_enable()

This commit modifies flexcan_chip_interrupts_enable() to disable all registered
IRQ lines around IMASK and CTRL register writes. Previously, only the primary
IRQ line was disabled, which left additional multi-IRQ lines active and could
allow handlers to fire while registers were inconsistent.

> diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
> index f73ff442d5304..7dde2e623defe 100644
> --- a/drivers/net/can/flexcan/flexcan-core.c
> +++ b/drivers/net/can/flexcan/flexcan-core.c
> @@ -1519,14 +1519,28 @@ static void flexcan_chip_interrupts_enable(const struct net_device *dev)
>  {
>  	const struct flexcan_priv *priv = netdev_priv(dev);
>  	struct flexcan_regs __iomem *regs = priv->regs;
> +	u32 quirks = priv->devtype_data.quirks;
>  	u64 reg_imask;
>  
>  	disable_irq(dev->irq);
> +	if (quirks & FLEXCAN_QUIRK_NR_IRQ_3) {
> +		disable_irq(priv->irq_boff);
> +		disable_irq(priv->irq_err);
> +	}
> +	if (quirks & FLEXCAN_QUIRK_SECONDARY_MB_IRQ)
> +		disable_irq(priv->irq_secondary_mb);
> +
>  	priv->write(priv->reg_ctrl_default, &regs->ctrl);
>  	reg_imask = priv->rx_mask | priv->tx_mask;
>  	priv->write(upper_32_bits(reg_imask), &regs->imask2);
>  	priv->write(lower_32_bits(reg_imask), &regs->imask1);
>  	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);
> +		enable_irq(priv->irq_err);
> +	}
>  }

[Severity: High]
This isn't a bug introduced by this patch, but is it possible for
flexcan_chip_interrupts_enable() to be called after flexcan_close() has
already freed the IRQs?

If the bus-off recovery worker (can_restart_work) runs concurrently with the
hardware teardown in flexcan_close(), could it trigger an interrupt storm?

flexcan_close() frees the requested IRQs and stops the chip, and then calls
close_candev():

drivers/net/can/flexcan/flexcan-core.c:flexcan_close() {
	...
	free_irq(dev->irq, dev);
	can_rx_offload_disable(&priv->offload);
	flexcan_chip_stop_disable_on_error(dev);

	can_rx_offload_del(&priv->offload);
	flexcan_transceiver_disable(priv);
	close_candev(dev);
	...
}

Because close_candev() is where cancel_delayed_work_sync(&priv->restart_work)
is called, the worker can execute while flexcan_close() is running.

If the worker executes its hardware initialization after free_irq() is called
but before close_candev() cancels it:

can_restart_work()->flexcan_set_mode()->flexcan_chip_interrupts_enable()

Will this re-enable chip-level interrupts while no handler is registered,
permanently disabling the shared IRQ line via the kernel's spurious interrupt
detector?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260609142954.1807421-1-ciprianmarian.costea@oss.nxp.com?part=2

Re: [PATCH v5 2/8] can: flexcan: disable all IRQ lines in flexcan_chip_interrupts_enable()

[Vincent Mailhol]

On 09/06/2026 at 16:29, Ciprian Costea wrote:
> From: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
> 
> flexcan_chip_interrupts_enable() disables only the primary IRQ line while
> writing to the IMASK and CTRL registers.
> 
> On multi-IRQ platforms (S32G2, MCF5441X), the additional IRQ lines (boff,
> err, secondary-mb) remain active so their handlers can fire while
> registers are inconsistent.
> 
> Disable all registered IRQ lines around the IMASK/CTRL writes. This
> also fixes the resume path, which calls this function.
> 
> Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
> Reviewed-and-tested-by: Haibo Chen <haibo.chen@nxp.com>
> Tested-by: Enric Balletbo i Serra <eballetb@redhat.com>

Reviewed-by: Vincent Mailhol <mailhol@kernel.org>


Yours sincerely,
Vincent Mailhol

[PATCH v5 3/8] can: flexcan: split rx/tx masks per mailbox IRQ line

[Ciprian Costea]

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

On S32G2, which has two mailbox IRQ lines (mb-0 for MBs 0-7, mb-1
for MBs 8-63), both handlers currently process the full rx_mask/tx_mask
range.

Introduce FLEXCAN_SECONDARY_MB_IRQ_MB0_MASK and
FLEXCAN_SECONDARY_MB_IRQ_MB1_MASK to describe the split, and pass
the selected mask to flexcan_do_mb() via a new mb_mask parameter.

In flexcan_irq_mb(), the irq argument selects the correct mask: the
primary MB IRQ uses MB0_MASK and the secondary uses MB1_MASK.

For single-IRQ platforms, mb_mask is ~0ULL with no functional change.

Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
Reviewed-and-tested-by: Haibo Chen <haibo.chen@nxp.com>
Tested-by: Enric Balletbo i Serra <eballetb@redhat.com>
---
 drivers/net/can/flexcan/flexcan-core.c | 39 ++++++++++++++++++--------
 1 file changed, 28 insertions(+), 11 deletions(-)

diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
index 7dde2e623def..0ed838f0719a 100644
--- a/drivers/net/can/flexcan/flexcan-core.c
+++ b/drivers/net/can/flexcan/flexcan-core.c
@@ -182,6 +182,12 @@
 #define FLEXCAN_IFLAG_RX_FIFO_WARN	BIT(6)
 #define FLEXCAN_IFLAG_RX_FIFO_AVAILABLE	BIT(5)
 
+/* On platforms with FLEXCAN_QUIRK_SECONDARY_MB_IRQ, the MB IRQ lines are
+ * split.
+ */
+#define FLEXCAN_SECONDARY_MB_IRQ_MB0_MASK	GENMASK_ULL(7, 0)
+#define FLEXCAN_SECONDARY_MB_IRQ_MB1_MASK	GENMASK_ULL(63, 8)
+
 /* FLEXCAN message buffers */
 #define FLEXCAN_MB_CODE_MASK		(0xf << 24)
 #define FLEXCAN_MB_CODE_RX_BUSY_BIT	(0x1 << 24)
@@ -957,14 +963,16 @@ static inline void flexcan_write64(struct flexcan_priv *priv, u64 val, void __io
 		priv->write(lower_32_bits(val), addr);
 }
 
-static inline u64 flexcan_read_reg_iflag_rx(struct flexcan_priv *priv)
+static inline u64 flexcan_read_reg_iflag_rx(struct flexcan_priv *priv,
+					    u64 rx_mask)
 {
-	return flexcan_read64_mask(priv, &priv->regs->iflag1, priv->rx_mask);
+	return flexcan_read64_mask(priv, &priv->regs->iflag1, rx_mask);
 }
 
-static inline u64 flexcan_read_reg_iflag_tx(struct flexcan_priv *priv)
+static inline u64 flexcan_read_reg_iflag_tx(struct flexcan_priv *priv,
+					    u64 tx_mask)
 {
-	return flexcan_read64_mask(priv, &priv->regs->iflag1, priv->tx_mask);
+	return flexcan_read64_mask(priv, &priv->regs->iflag1, tx_mask);
 }
 
 static inline struct flexcan_priv *rx_offload_to_priv(struct can_rx_offload *offload)
@@ -1071,12 +1079,14 @@ static struct sk_buff *flexcan_mailbox_read(struct can_rx_offload *offload,
 }
 
 /* Process mailbox (RX + TX) events */
-static irqreturn_t flexcan_do_mb(struct net_device *dev)
+static irqreturn_t flexcan_do_mb(struct net_device *dev, u64 mb_mask)
 {
 	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 rx_mask = priv->rx_mask & mb_mask;
+	u64 tx_mask = priv->tx_mask & mb_mask;
 	u64 reg_iflag_tx;
 
 	/* reception interrupt */
@@ -1084,7 +1094,8 @@ static irqreturn_t flexcan_do_mb(struct net_device *dev)
 		u64 reg_iflag_rx;
 		int ret;
 
-		while ((reg_iflag_rx = flexcan_read_reg_iflag_rx(priv))) {
+		while ((reg_iflag_rx = flexcan_read_reg_iflag_rx(priv,
+								 rx_mask))) {
 			handled = IRQ_HANDLED;
 			ret = can_rx_offload_irq_offload_timestamp(&priv->offload,
 								   reg_iflag_rx);
@@ -1110,10 +1121,10 @@ static irqreturn_t flexcan_do_mb(struct net_device *dev)
 		}
 	}
 
-	reg_iflag_tx = flexcan_read_reg_iflag_tx(priv);
+	reg_iflag_tx = flexcan_read_reg_iflag_tx(priv, tx_mask);
 
 	/* transmission complete interrupt */
-	if (reg_iflag_tx & priv->tx_mask) {
+	if (reg_iflag_tx & tx_mask) {
 		u32 reg_ctrl = priv->read(&priv->tx_mb->can_ctrl);
 
 		handled = IRQ_HANDLED;
@@ -1125,7 +1136,7 @@ static irqreturn_t flexcan_do_mb(struct net_device *dev)
 		/* after sending a RTR frame MB is in RX mode */
 		priv->write(FLEXCAN_MB_CODE_TX_INACTIVE,
 			    &priv->tx_mb->can_ctrl);
-		flexcan_write64(priv, priv->tx_mask, &regs->iflag1);
+		flexcan_write64(priv, tx_mask, &regs->iflag1);
 		netif_wake_queue(dev);
 	}
 
@@ -1228,7 +1239,7 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id)
 	struct flexcan_priv *priv = netdev_priv(dev);
 	irqreturn_t handled;
 
-	handled = flexcan_do_mb(dev);
+	handled = flexcan_do_mb(dev, ~0ULL);
 	handled |= flexcan_do_state(dev);
 	handled |= flexcan_do_berr(dev);
 
@@ -1244,8 +1255,14 @@ 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;
+	u64 mb_mask = ~0ULL;
+
+	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SECONDARY_MB_IRQ)
+		mb_mask = (irq == priv->irq_secondary_mb) ?
+			  FLEXCAN_SECONDARY_MB_IRQ_MB1_MASK :
+			  FLEXCAN_SECONDARY_MB_IRQ_MB0_MASK;
 
-	handled = flexcan_do_mb(dev);
+	handled = flexcan_do_mb(dev, mb_mask);
 
 	if (handled)
 		can_rx_offload_irq_finish(&priv->offload);
-- 
2.43.0

Re: [PATCH v5 3/8] can: flexcan: split rx/tx masks per mailbox IRQ line

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [Critical] Concurrent execution of split IRQ handlers corrupts the lockless `skb_irq_queue`.
--

commit aded1fca2efad9bc2736fa7932119f27a1b0a87c
Author: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>

can: flexcan: split rx/tx masks per mailbox IRQ line

This patch splits the mailbox IRQ handling into separate lines for MB0 and
MB1 on S32G2 platforms. It passes a mailbox mask into flexcan_do_mb() to
ensure each IRQ handler only processes the rx and tx flags for its designated
mailboxes.

> diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
> index 7dde2e623defe..0ed838f0719aa 100644
> --- a/drivers/net/can/flexcan/flexcan-core.c
> +++ b/drivers/net/can/flexcan/flexcan-core.c
[ ... ]
> @@ -1244,8 +1255,14 @@ 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;
> +	u64 mb_mask = ~0ULL;
> +
> +	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SECONDARY_MB_IRQ)
> +		mb_mask = (irq == priv->irq_secondary_mb) ?
> +			  FLEXCAN_SECONDARY_MB_IRQ_MB1_MASK :
> +			  FLEXCAN_SECONDARY_MB_IRQ_MB0_MASK;
>  
> -	handled = flexcan_do_mb(dev);
> +	handled = flexcan_do_mb(dev, mb_mask);

[Severity: Critical]
This is a pre-existing issue, but since there are two separate IRQ lines 
assigned to flexcan_irq_mb(), could they fire concurrently on different CPUs
and corrupt the rx-offload queues?

Both handlers call flexcan_do_mb() which then calls 
can_rx_offload_irq_offload_timestamp():

drivers/net/can/dev/rx-offload.c:can_rx_offload_irq_offload_timestamp() {
    ...
    __skb_queue_add_sort(&offload->skb_irq_queue, skb, can_rx_offload_compare);
    ...
}

Because __skb_queue_add_sort() modifies the list locklessly, it assumes a
strict single-IRQ serialization model. If the primary and secondary MB IRQ
handlers execute at the same time, this will lead to concurrent insertions
corrupting the doubly-linked list. Is there any mechanism restricting the CPU
affinity or preventing concurrent execution of these IRQs?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260609142954.1807421-1-ciprianmarian.costea@oss.nxp.com?part=3

Re: [PATCH v5 3/8] can: flexcan: split rx/tx masks per mailbox IRQ line

[Vincent Mailhol]

On 09/06/2026 at 16:29, Ciprian Costea wrote:
> From: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
> 
> On S32G2, which has two mailbox IRQ lines (mb-0 for MBs 0-7, mb-1
> for MBs 8-63), both handlers currently process the full rx_mask/tx_mask
> range.
> 
> Introduce FLEXCAN_SECONDARY_MB_IRQ_MB0_MASK and
> FLEXCAN_SECONDARY_MB_IRQ_MB1_MASK to describe the split, and pass
> the selected mask to flexcan_do_mb() via a new mb_mask parameter.
> 
> In flexcan_irq_mb(), the irq argument selects the correct mask: the
> primary MB IRQ uses MB0_MASK and the secondary uses MB1_MASK.
> 
> For single-IRQ platforms, mb_mask is ~0ULL with no functional change.
> 
> Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
> Reviewed-and-tested-by: Haibo Chen <haibo.chen@nxp.com>
> Tested-by: Enric Balletbo i Serra <eballetb@redhat.com>

Looks better than v5!

Reviewed-by: Vincent Mailhol <mailhol@kernel.org>

> ---
>  drivers/net/can/flexcan/flexcan-core.c | 39 ++++++++++++++++++--------
>  1 file changed, 28 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
> index 7dde2e623def..0ed838f0719a 100644
> --- a/drivers/net/can/flexcan/flexcan-core.c
> +++ b/drivers/net/can/flexcan/flexcan-core.c
> @@ -182,6 +182,12 @@
>  #define FLEXCAN_IFLAG_RX_FIFO_WARN	BIT(6)
>  #define FLEXCAN_IFLAG_RX_FIFO_AVAILABLE	BIT(5)
>  
> +/* On platforms with FLEXCAN_QUIRK_SECONDARY_MB_IRQ, the MB IRQ lines are
> + * split.
> + */
> +#define FLEXCAN_SECONDARY_MB_IRQ_MB0_MASK	GENMASK_ULL(7, 0)
> +#define FLEXCAN_SECONDARY_MB_IRQ_MB1_MASK	GENMASK_ULL(63, 8)

Nitpick: priv->rx_mask, priv->tx_mask and your mb_mask variable all have
type u64 so you could have used GENMASK_U64() to stay coherent with the
type. But you don't have to send a v6 just for this.

>  /* FLEXCAN message buffers */
>  #define FLEXCAN_MB_CODE_MASK		(0xf << 24)
>  #define FLEXCAN_MB_CODE_RX_BUSY_BIT	(0x1 << 24)
> @@ -957,14 +963,16 @@ static inline void flexcan_write64(struct flexcan_priv *priv, u64 val, void __io
>  		priv->write(lower_32_bits(val), addr);
>  }
>  
> -static inline u64 flexcan_read_reg_iflag_rx(struct flexcan_priv *priv)
> +static inline u64 flexcan_read_reg_iflag_rx(struct flexcan_priv *priv,
> +					    u64 rx_mask)
>  {
> -	return flexcan_read64_mask(priv, &priv->regs->iflag1, priv->rx_mask);
> +	return flexcan_read64_mask(priv, &priv->regs->iflag1, rx_mask);
>  }
>  
> -static inline u64 flexcan_read_reg_iflag_tx(struct flexcan_priv *priv)
> +static inline u64 flexcan_read_reg_iflag_tx(struct flexcan_priv *priv,
> +					    u64 tx_mask)
>  {
> -	return flexcan_read64_mask(priv, &priv->regs->iflag1, priv->tx_mask);
> +	return flexcan_read64_mask(priv, &priv->regs->iflag1, tx_mask);
>  }
>  
>  static inline struct flexcan_priv *rx_offload_to_priv(struct can_rx_offload *offload)
> @@ -1071,12 +1079,14 @@ static struct sk_buff *flexcan_mailbox_read(struct can_rx_offload *offload,
>  }
>  
>  /* Process mailbox (RX + TX) events */
> -static irqreturn_t flexcan_do_mb(struct net_device *dev)
> +static irqreturn_t flexcan_do_mb(struct net_device *dev, u64 mb_mask)
>  {
>  	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 rx_mask = priv->rx_mask & mb_mask;
> +	u64 tx_mask = priv->tx_mask & mb_mask;
>  	u64 reg_iflag_tx;
>  
>  	/* reception interrupt */
> @@ -1084,7 +1094,8 @@ static irqreturn_t flexcan_do_mb(struct net_device *dev)
>  		u64 reg_iflag_rx;
>  		int ret;
>  
> -		while ((reg_iflag_rx = flexcan_read_reg_iflag_rx(priv))) {
> +		while ((reg_iflag_rx = flexcan_read_reg_iflag_rx(priv,
> +								 rx_mask))) {
>  			handled = IRQ_HANDLED;
>  			ret = can_rx_offload_irq_offload_timestamp(&priv->offload,
>  								   reg_iflag_rx);
> @@ -1110,10 +1121,10 @@ static irqreturn_t flexcan_do_mb(struct net_device *dev)
>  		}
>  	}
>  
> -	reg_iflag_tx = flexcan_read_reg_iflag_tx(priv);
> +	reg_iflag_tx = flexcan_read_reg_iflag_tx(priv, tx_mask);
>  
>  	/* transmission complete interrupt */
> -	if (reg_iflag_tx & priv->tx_mask) {
> +	if (reg_iflag_tx & tx_mask) {
>  		u32 reg_ctrl = priv->read(&priv->tx_mb->can_ctrl);
>  
>  		handled = IRQ_HANDLED;
> @@ -1125,7 +1136,7 @@ static irqreturn_t flexcan_do_mb(struct net_device *dev)
>  		/* after sending a RTR frame MB is in RX mode */
>  		priv->write(FLEXCAN_MB_CODE_TX_INACTIVE,
>  			    &priv->tx_mb->can_ctrl);
> -		flexcan_write64(priv, priv->tx_mask, &regs->iflag1);
> +		flexcan_write64(priv, tx_mask, &regs->iflag1);
>  		netif_wake_queue(dev);
>  	}
>  
> @@ -1228,7 +1239,7 @@ static irqreturn_t flexcan_irq(int irq, void *dev_id)
>  	struct flexcan_priv *priv = netdev_priv(dev);
>  	irqreturn_t handled;
>  
> -	handled = flexcan_do_mb(dev);
> +	handled = flexcan_do_mb(dev, ~0ULL);
>  	handled |= flexcan_do_state(dev);
>  	handled |= flexcan_do_berr(dev);
>  
> @@ -1244,8 +1255,14 @@ 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;
> +	u64 mb_mask = ~0ULL;
> +
> +	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SECONDARY_MB_IRQ)
> +		mb_mask = (irq == priv->irq_secondary_mb) ?
> +			  FLEXCAN_SECONDARY_MB_IRQ_MB1_MASK :
> +			  FLEXCAN_SECONDARY_MB_IRQ_MB0_MASK;
>  
> -	handled = flexcan_do_mb(dev);
> +	handled = flexcan_do_mb(dev, mb_mask);
>  
>  	if (handled)
>  		can_rx_offload_irq_finish(&priv->offload);


Yours sincerely,
Vincent Mailhol

[PATCH v5 4/8] 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>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-and-tested-by: Haibo Chen <haibo.chen@nxp.com>
Tested-by: Enric Balletbo i Serra <eballetb@redhat.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

[PATCH v5 5/8] 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.

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>
Reviewed-and-tested-by: Haibo Chen <haibo.chen@nxp.com>
Tested-by: Enric Balletbo i Serra <eballetb@redhat.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 0ed838f0719a..adf3af57fb0a 100644
--- a/drivers/net/can/flexcan/flexcan-core.c
+++ b/drivers/net/can/flexcan/flexcan-core.c
@@ -1300,6 +1300,22 @@ 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);
@@ -1540,10 +1556,10 @@ 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);
 
@@ -1554,10 +1570,10 @@ 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)
@@ -1881,7 +1897,8 @@ 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
@@ -1902,6 +1919,13 @@ 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);
@@ -1916,7 +1940,8 @@ 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)
@@ -1948,10 +1973,12 @@ 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);
@@ -2338,12 +2365,21 @@ 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

Re: [PATCH v5 5/8] can: flexcan: add FLEXCAN_QUIRK_IRQ_BERR quirk

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [Critical] Concurrent lockless modification of `skb_irq_queue` due to multiple independent IRQ handlers.
--

commit 715613f4f6a66b4bd5ff74d8a150e7fa13ca4aa1
Author: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>

can: flexcan: add FLEXCAN_QUIRK_IRQ_BERR quirk

This patch introduces the FLEXCAN_QUIRK_IRQ_BERR quirk for hardware that
has a dedicated interrupt line for bus errors and state changes. It adds
the flexcan_irq_esr() handler and updates IRQ enabling/disabling to
support the NXP S32N79 SoC.

> diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
> --- a/drivers/net/can/flexcan/flexcan-core.c
> +++ b/drivers/net/can/flexcan/flexcan-core.c
> @@ -1300,6 +1300,22 @@ 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;
> +}
> +

[ ... ]

> @@ -1902,6 +1919,13 @@ 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);

[Severity: Critical]
This isn't a bug introduced by this patch, but it expands a pre-existing
race condition to the S32N79 SoC by registering another concurrent hardware
IRQ handler.

Does registering multiple independent IRQ lines lead to concurrent lockless
modifications of the CAN rx-offload subsystem's skb_irq_queue?

If flexcan_irq_mb() and flexcan_irq_esr() trigger concurrently on different
CPUs:

CPU1 (flexcan_irq_mb)
flexcan_do_mb()
   can_rx_offload_queue_timestamp()
      __skb_queue_add_sort()  <-- lockless push

CPU2 (flexcan_irq_esr)
flexcan_do_state()
   can_rx_offload_queue_timestamp()
      __skb_queue_add_sort()  <-- concurrent lockless push

Or CPU1 could call can_rx_offload_irq_finish() (which splices the queue)
while CPU2 is pushing a new skb. Can this corrupt the doubly linked
skb_irq_queue pointers and cause kernel panics?

> +		if (err)
> +			goto out_free_irq_boff;
> +	}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260609142954.1807421-1-ciprianmarian.costea@oss.nxp.com?part=5

Re: [PATCH v5 5/8] can: flexcan: add FLEXCAN_QUIRK_IRQ_BERR quirk

[Vincent Mailhol]

On 09/06/2026 at 16:29, Ciprian Costea wrote:
> 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>
> Reviewed-and-tested-by: Haibo Chen <haibo.chen@nxp.com>
> Tested-by: Enric Balletbo i Serra <eballetb@redhat.com>

Reviewed-by: Vincent Mailhol <mailhol@kernel.org>

> ---
>  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 0ed838f0719a..adf3af57fb0a 100644
> --- a/drivers/net/can/flexcan/flexcan-core.c
> +++ b/drivers/net/can/flexcan/flexcan-core.c
> @@ -1300,6 +1300,22 @@ 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);
> @@ -1540,10 +1556,10 @@ 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);
>  
> @@ -1554,10 +1570,10 @@ 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)
> @@ -1881,7 +1897,8 @@ 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
> @@ -1902,6 +1919,13 @@ 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);
> @@ -1916,7 +1940,8 @@ 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)
> @@ -1948,10 +1973,12 @@ 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);
> @@ -2338,12 +2365,21 @@ 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;
>  		}
> +

Nitpick: you shouldn't have unrelated changes, like this newline
addition, in you patches.

@Marc, do you mind removing this while applying?

>  		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 */


Yours sincerely,
Vincent Mailhol

[PATCH v5 6/8] 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>
Reviewed-and-tested-by: Haibo Chen <haibo.chen@nxp.com>
Tested-by: Enric Balletbo i Serra <eballetb@redhat.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 adf3af57fb0a..b43d60fab4b6 100644
--- a/drivers/net/can/flexcan/flexcan-core.c
+++ b/drivers/net/can/flexcan/flexcan-core.c
@@ -403,6 +403,15 @@ 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,
@@ -2222,6 +2231,7 @@ 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

Re: [PATCH v5 6/8] can: flexcan: add NXP S32N79 SoC support

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] Missing `enable_irq_wake()` for the actual device state change/wakeup interrupt on multi-IRQ platforms.
--

commit 92f9d2a83610f1e8d4d83febb9e00ed2aea10a29
Author: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>

can: flexcan: add NXP S32N79 SoC support

Adds device data and compatible string for NXP S32N79 SoC. The FlexCAN IP
integration on this SoC uses two interrupts, separating mailboxes from bus
errors and device state changes.

> diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
> --- a/drivers/net/can/flexcan/flexcan-core.c
> +++ b/drivers/net/can/flexcan/flexcan-core.c
[ ... ]
> @@ -403,6 +403,15 @@ 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,

[Severity: High]
This isn't a bug introduced by this patch, but this is a pre-existing issue
with platforms that use FLEXCAN_QUIRK_IRQ_BERR.

Will this platform fail to wake up from sleep upon CAN activity?

In flexcan_suspend() and flexcan_resume(), the code configures wakeup using
the primary interrupt:

flexcan_suspend() {
    ...
    enable_irq_wake(dev->irq);
    ...
}

However, on multi-IRQ platforms using FLEXCAN_QUIRK_IRQ_BERR, the device
state change and wakeup interrupt is handled by flexcan_irq_esr() and routed
to priv->irq_err (or priv->irq_boff). Since dev->irq is strictly dedicated
to mailboxes on these platforms and ignores device state changes, the
correct interrupt is never configured as a system wakeup source.

Should the suspend and resume routines be updated to call enable_irq_wake()
and disable_irq_wake() on priv->irq_err for platforms with this quirk?

> +};

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260609142954.1807421-1-ciprianmarian.costea@oss.nxp.com?part=6

Re: [PATCH v5 6/8] can: flexcan: add NXP S32N79 SoC support

[Vincent Mailhol]

On 09/06/2026 at 16:29, Ciprian Costea wrote:
> 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>
> Reviewed-and-tested-by: Haibo Chen <haibo.chen@nxp.com>
> Tested-by: Enric Balletbo i Serra <eballetb@redhat.com>

Reviewed-by: Vincent Mailhol <mailhol@kernel.org>


Yours sincerely,
Vincent Mailhol

[PATCH v5 7/8] 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>
Reviewed-and-tested-by: Haibo Chen <haibo.chen@nxp.com>
Tested-by: Enric Balletbo i Serra <eballetb@redhat.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 v5 8/8] 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>
Reviewed-and-tested-by: Haibo Chen <haibo.chen@nxp.com>
Tested-by: Enric Balletbo i Serra <eballetb@redhat.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