[PATCH 0/3] mailbox: renesas: Support MFIS mailbox driver

[PATCH 0/3] mailbox: renesas: Support MFIS mailbox driver

[Kuninori Morimoto]

Hi

This patch-set adds Renesas MFIS Mailbox driver.
[PATCH 1/3] is cleanup patch for Kconfig

Kuninori Morimoto (2):
  mailbox: remove unneeded double quotation
  dt-bindings: mailbox: Add Renesas MFIS Mailbox

Masashi Ozaki (1):
  mailbox: renesas: Support MFIS mailbox driver

 .../mailbox/renesas,mfis-mailbox.yaml         |  49 +++++++
 drivers/mailbox/Kconfig                       |  12 +-
 drivers/mailbox/Makefile                      |   2 +
 drivers/mailbox/rcar-mfis-mailbox.c           | 137 ++++++++++++++++++
 4 files changed, 198 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/mailbox/renesas,mfis-mailbox.yaml
 create mode 100644 drivers/mailbox/rcar-mfis-mailbox.c

-- 
2.43.0

[PATCH 1/3] mailbox: remove unneeded double quotation

[Kuninori Morimoto]

It makes Kconfig strange. fix it.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
---
 drivers/mailbox/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index 29f16f220384f..e47cb68989267 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -279,7 +279,7 @@ config MTK_ADSP_MBOX
 	tristate "MediaTek ADSP Mailbox Controller"
 	depends on ARCH_MEDIATEK || COMPILE_TEST
 	help
-          Say yes here to add support for "MediaTek ADSP Mailbox Controller.
+          Say yes here to add support for MediaTek ADSP Mailbox Controller.
           This mailbox driver is used to send notification or short message
           between processors with ADSP. It will place the message to share
 	  buffer and will access the ipc control.
-- 
2.43.0

[PATCH 2/3] mailbox: renesas: Support MFIS mailbox driver

[Kuninori Morimoto]

From: Masashi Ozaki <masashi.ozaki.te@renesas.com>

Add Renesas MFIS mailbox driver for R8A78000 (X5H)

Signed-off-by: Masashi Ozaki <masashi.ozaki.te@renesas.com>
Signed-off-by: Vinh Nguyen <vinh.nguyen.xz@renesas.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
---
 drivers/mailbox/Kconfig             |  10 +-
 drivers/mailbox/Makefile            |   2 +
 drivers/mailbox/rcar-mfis-mailbox.c | 137 ++++++++++++++++++++++++++++
 3 files changed, 148 insertions(+), 1 deletion(-)
 create mode 100644 drivers/mailbox/rcar-mfis-mailbox.c

diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index e47cb68989267..07e6bf06effe3 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -379,6 +379,15 @@ config BCM74110_MAILBOX
 	  processor and coprocessor that handles various power management task
 	  and more.
 
+config RCAR_MFIS_MBOX
+	bool "Renesas R-Car Multifunctional Interface Mailbox Support"
+	depends on ARM_SCMI_PROTOCOL && ARCH_RENESAS
+	help
+	  This driver provides support for SCMI interface transport with
+	  MFIS(Multifunctional Interface).
+	  It is used to send short message between CPU cores and
+	  SCP(System Control Processor).
+
 config RISCV_SBI_MPXY_MBOX
 	tristate "RISC-V SBI Message Proxy (MPXY) Mailbox"
 	depends on RISCV_SBI
@@ -389,5 +398,4 @@ config RISCV_SBI_MPXY_MBOX
 	  remote processor through the SBI implementation (M-mode firmware
 	  or HS-mode hypervisor). Say Y here if you want to have this support.
 	  If unsure say N.
-
 endif
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index 81820a4f55285..060a9c7f6727b 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -27,6 +27,8 @@ obj-$(CONFIG_PL320_MBOX)	+= pl320-ipc.o
 
 obj-$(CONFIG_OMAP2PLUS_MBOX)	+= omap-mailbox.o
 
+obj-$(CONFIG_RCAR_MFIS_MBOX)	+= rcar-mfis-mailbox.o
+
 obj-$(CONFIG_ROCKCHIP_MBOX)	+= rockchip-mailbox.o
 
 obj-$(CONFIG_PCC)		+= pcc.o
diff --git a/drivers/mailbox/rcar-mfis-mailbox.c b/drivers/mailbox/rcar-mfis-mailbox.c
new file mode 100644
index 0000000000000..54cabfa305eb4
--- /dev/null
+++ b/drivers/mailbox/rcar-mfis-mailbox.c
@@ -0,0 +1,137 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Renesas MFIS (Multifunctional Interface) Mailbox Driver
+ *
+ * Copyright (c) 2025, Renesas Electronics Corporation. All rights reserved.
+ */
+
+#include <linux/device.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/interrupt.h>
+#include <linux/mailbox_controller.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+static int mfis_send_data(struct mbox_chan *link, void *data)
+{
+	void __iomem *reg = link->con_priv;
+
+	/*Trigger interrupt request to firmware(SCP)*/
+	iowrite32(0x1, reg);
+
+	return 0;
+}
+
+static irqreturn_t mfis_rx_interrupt(int irq, void *data)
+{
+	struct mbox_chan *link = data;
+	void __iomem *reg = link->con_priv;
+
+	mbox_chan_received_data(link, 0);
+
+	/* Clear interrupt register */
+	iowrite32(0x0, reg);
+
+	return IRQ_HANDLED;
+}
+
+static int mfis_startup(struct mbox_chan *link)
+{
+	struct mbox_controller *mbox = link->mbox;
+	struct device *dev = mbox->dev;
+	int irq;
+	int ret;
+
+	irq = of_irq_get(dev->of_node, 0);
+
+	ret = request_irq(irq, mfis_rx_interrupt,
+			  IRQF_SHARED, "mfis-mbox", link);
+	if (ret) {
+		dev_err(dev,
+			"Unable to acquire IRQ %d\n", irq);
+		return ret;
+	}
+	return 0;
+}
+
+static void mfis_shutdown(struct mbox_chan *link)
+{
+	struct mbox_controller *mbox = link->mbox;
+	struct device *dev = mbox->dev;
+	int irq;
+
+	irq = of_irq_get(dev->of_node, 0);
+
+	free_irq(irq, link);
+}
+
+static bool mfis_last_tx_done(struct mbox_chan *link)
+{
+	return true;
+}
+
+static const struct mbox_chan_ops mfis_chan_ops = {
+	.send_data	= mfis_send_data,
+	.startup	= mfis_startup,
+	.shutdown	= mfis_shutdown,
+	.last_tx_done	= mfis_last_tx_done
+};
+
+static int mfis_mbox_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mbox_controller *mbox;
+	void __iomem *reg;
+	int ret, count = 2, i;
+
+	mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
+	if (!mbox)
+		return -ENOMEM;
+
+	mbox->chans = devm_kcalloc(dev, count, sizeof(*mbox->chans), GFP_KERNEL);
+	if (!mbox->chans)
+		return -ENOMEM;
+
+	reg = devm_platform_ioremap_resource(pdev, i);
+	if (IS_ERR(reg))
+		return PTR_ERR(reg);
+
+	for (i = 0; i < count; i++) {
+		mbox->chans[i].mbox	= mbox;
+		mbox->chans[i].con_priv	= reg + ((1 - i) * 4);
+	}
+
+	mbox->txdone_poll	= true;
+	mbox->txdone_irq	= false;
+	mbox->txpoll_period	= 1;
+	mbox->num_chans		= count;
+	mbox->ops		= &mfis_chan_ops;
+	mbox->dev		= dev;
+
+	ret = mbox_controller_register(mbox);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, mbox);
+	dev_info(dev, "MFIS mailbox is probed\n");
+
+	return 0;
+}
+
+static const struct of_device_id mfis_mbox_of_match[] = {
+	{ .compatible = "renesas,mfis-mbox", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mfis_mbox_of_match);
+
+static struct platform_driver mfis_mbox_driver = {
+	.driver = {
+		.name = "renesas-mfis-mbox",
+		.of_match_table = mfis_mbox_of_match,
+	},
+	.probe	= mfis_mbox_probe,
+};
+module_platform_driver(mfis_mbox_driver);
+MODULE_DESCRIPTION("Renesas MFIS mailbox driver");
+MODULE_LICENSE("GPL v2");
-- 
2.43.0

[PATCH 3/3] dt-bindings: mailbox: Add Renesas MFIS Mailbox

[Kuninori Morimoto]

Add device tree bindings for the Renesas Multifunctional Interface
(MFIS) a mailbox controller.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
---
 .../mailbox/renesas,mfis-mailbox.yaml         | 49 +++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/renesas,mfis-mailbox.yaml

diff --git a/Documentation/devicetree/bindings/mailbox/renesas,mfis-mailbox.yaml b/Documentation/devicetree/bindings/mailbox/renesas,mfis-mailbox.yaml
new file mode 100644
index 0000000000000..b9b6e6d440d79
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/renesas,mfis-mailbox.yaml
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mailbox/renesas,mfis-mailbox.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas MFIS (Multifunctional Interface) Mailbox Driver
+
+maintainers:
+  - Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
+
+description: |
+    The R-Car multifunctional interface (MFIS) provides an interface between
+    the different CPU Cores, such as AP System Core domain and the Realtime
+    Core domain, SCP Core domain and AP System Core domain or Realtime Core
+    domain and AP System Core domain or Realtime Core domain.
+    The MFIS supports the issuing of interrupts for each CPU core domain.
+
+properties:
+  compatible:
+    const: renesas,mfis-mbox
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    description: the irq line
+    maxItems: 1
+
+  "#mbox-cells":
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - "#mbox-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    mailbox: mfis_mbox@18842000  {
+        compatible = "renesas,mfis-mbox";
+        reg = <0x18842000 0x8>;
+        interrupts = <GIC_SPI 4362 IRQ_TYPE_LEVEL_HIGH>;
+        #mbox-cells = <1>;
+    };
-- 
2.43.0

Re: [PATCH 3/3] dt-bindings: mailbox: Add Renesas MFIS Mailbox

[Rob Herring (Arm)]

On Fri, 24 Oct 2025 06:22:18 +0000, Kuninori Morimoto wrote:
> Add device tree bindings for the Renesas Multifunctional Interface
> (MFIS) a mailbox controller.
> 
> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
> ---
>  .../mailbox/renesas,mfis-mailbox.yaml         | 49 +++++++++++++++++++
>  1 file changed, 49 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mailbox/renesas,mfis-mailbox.yaml
> 

My bot found errors running 'make dt_binding_check' on your patch:

yamllint warnings/errors:

dtschema/dtc warnings/errors:
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/mailbox/renesas,mfis-mailbox.example.dtb: mfis_mbox@18842000 (renesas,mfis-mbox): compatible:0: 'anyOf' conditional failed, one must be fixed:
	'renesas,mfis-mbox' does not match '^renesas,(emev2|r(7s|8a|9a)[a-z0-9]+|rcar|rmobile|rz[a-z0-9]*|sh(7[a-z0-9]+)?|mobile)-[a-z0-9-]+$'
	'renesas,mfis-mbox' does not match '^renesas,(condor|falcon|gr-peach|gray-hawk|salvator|sk-rz|smar(c(2)?)?|spider|white-hawk)(.*)?$'
	'renesas,mfis-mbox' does not match '^renesas,(can|cpg|dmac|du|(g)?ether(avb)?|gpio|hscif|(r)?i[i2]c|imr|intc|ipmmu|irqc|jpu|mmcif|msiof|mtu2|pci(e)?|pfc|pwm|[rq]spi|rcar_sound|sata|scif[ab]*|sdhi|thermal|tmu|tpu|usb(2|hs)?|vin|xhci)-[a-z0-9-]+$'
	'renesas,mfis-mbox' does not match '^renesas,(d|s)?bsc(3)?-(r8a73a4|r8a7740|sh73a0)$'
	'renesas,mfis-mbox' does not match '^renesas,em-(gio|sti|uart)$'
	'renesas,mfis-mbox' does not match '^renesas,fsi2-(r8a7740|sh73a0)$'
	'renesas,mfis-mbox' does not match '^renesas,hspi-r8a777[89]$'
	'renesas,mfis-mbox' does not match '^renesas,sysc-(r8a73a4|r8a7740|rmobile|sh73a0)$'
	'renesas,mfis-mbox' is not one of ['renesas,imr-lx4', 'renesas,mtu2-r7s72100']
	'renesas,mfis-mbox' is not one of ['renesas,smp-sram']
	'renesas,mfis-mbox' does not match '^(?!renesas,.+-.+).+$'
	from schema $id: http://devicetree.org/schemas/soc/renesas/renesas-soc.yaml

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/87bjlwn7j9.wl-kuninori.morimoto.gx@renesas.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.

Re: [PATCH 2/3] mailbox: renesas: Support MFIS mailbox driver

[Krzysztof Kozlowski]

On 24/10/2025 08:22, Kuninori Morimoto wrote:
> From: Masashi Ozaki <masashi.ozaki.te@renesas.com>
> 
> Add Renesas MFIS mailbox driver for R8A78000 (X5H)
> 
> Signed-off-by: Masashi Ozaki <masashi.ozaki.te@renesas.com>
> Signed-off-by: Vinh Nguyen <vinh.nguyen.xz@renesas.com>
> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
> ---
>  drivers/mailbox/Kconfig             |  10 +-
>  drivers/mailbox/Makefile            |   2 +
>  drivers/mailbox/rcar-mfis-mailbox.c | 137 ++++++++++++++++++++++++++++
>  3 files changed, 148 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/mailbox/rcar-mfis-mailbox.c
> 
> diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
> index e47cb68989267..07e6bf06effe3 100644
> --- a/drivers/mailbox/Kconfig
> +++ b/drivers/mailbox/Kconfig
> @@ -379,6 +379,15 @@ config BCM74110_MAILBOX
>  	  processor and coprocessor that handles various power management task
>  	  and more.
>  
> +config RCAR_MFIS_MBOX
> +	bool "Renesas R-Car Multifunctional Interface Mailbox Support"
> +	depends on ARM_SCMI_PROTOCOL && ARCH_RENESAS

I don't see any build restrictions, why no compile test?

> +	help
> +	  This driver provides support for SCMI interface transport with
> +	  MFIS(Multifunctional Interface).
> +	  It is used to send short message between CPU cores and
> +	  SCP(System Control Processor).
> +
>  config RISCV_SBI_MPXY_MBOX
>  	tristate "RISC-V SBI Message Proxy (MPXY) Mailbox"
>  	depends on RISCV_SBI
> @@ -389,5 +398,4 @@ config RISCV_SBI_MPXY_MBOX
>  	  remote processor through the SBI implementation (M-mode firmware
>  	  or HS-mode hypervisor). Say Y here if you want to have this support.
>  	  If unsure say N.
> -


Does not look as intended change.

...

> +
> +static int mfis_startup(struct mbox_chan *link)
> +{
> +	struct mbox_controller *mbox = link->mbox;
> +	struct device *dev = mbox->dev;
> +	int irq;
> +	int ret;
> +
> +	irq = of_irq_get(dev->of_node, 0);
> +
> +	ret = request_irq(irq, mfis_rx_interrupt,
> +			  IRQF_SHARED, "mfis-mbox", link);
> +	if (ret) {
> +		dev_err(dev,
> +			"Unable to acquire IRQ %d\n", irq);

Please don't wrap lines when not necessary. This only hurts readability.


> +		return ret;
> +	}



> +
> +	ret = mbox_controller_register(mbox);
> +	if (ret)
> +		return ret;
> +
> +	platform_set_drvdata(pdev, mbox);
> +	dev_info(dev, "MFIS mailbox is probed\n");


This does not look like useful printk message. Drivers should be silent
on success:
https://elixir.bootlin.com/linux/v6.15-rc7/source/Documentation/process/coding-style.rst#L913
https://elixir.bootlin.com/linux/v6.15-rc7/source/Documentation/process/debugging/driver_development_debugging_guide.rst#L79

> +
> +	return 0;
> +}
> +
> +static const struct of_device_id mfis_mbox_of_match[] = {
> +	{ .compatible = "renesas,mfis-mbox", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, mfis_mbox_of_match);
> +
> +static struct platform_driver mfis_mbox_driver = {
> +	.driver = {
> +		.name = "renesas-mfis-mbox",
> +		.of_match_table = mfis_mbox_of_match,
> +	},
> +	.probe	= mfis_mbox_probe,
> +};
> +module_platform_driver(mfis_mbox_driver);
> +MODULE_DESCRIPTION("Renesas MFIS mailbox driver");
> +MODULE_LICENSE("GPL v2");


Best regards,
Krzysztof

Re: [PATCH 3/3] dt-bindings: mailbox: Add Renesas MFIS Mailbox

[Krzysztof Kozlowski]

On 24/10/2025 08:22, Kuninori Morimoto wrote:
> Add device tree bindings for the Renesas Multifunctional Interface
> (MFIS) a mailbox controller.
> 
> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
> ---
>  .../mailbox/renesas,mfis-mailbox.yaml         | 49 +++++++++++++++++++
>  1 file changed, 49 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mailbox/renesas,mfis-mailbox.yaml
> 
> diff --git a/Documentation/devicetree/bindings/mailbox/renesas,mfis-mailbox.yaml b/Documentation/devicetree/bindings/mailbox/renesas,mfis-mailbox.yaml
> new file mode 100644
> index 0000000000000..b9b6e6d440d79
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mailbox/renesas,mfis-mailbox.yaml

Filename must match compatible. See writing bindings.

> @@ -0,0 +1,49 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/mailbox/renesas,mfis-mailbox.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Renesas MFIS (Multifunctional Interface) Mailbox Driver

Driver as Linux driver? No, please describe hardware.

> +
> +maintainers:
> +  - Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
> +
> +description: |

Drop |

> +    The R-Car multifunctional interface (MFIS) provides an interface between
> +    the different CPU Cores, such as AP System Core domain and the Realtime
> +    Core domain, SCP Core domain and AP System Core domain or Realtime Core
> +    domain and AP System Core domain or Realtime Core domain.
> +    The MFIS supports the issuing of interrupts for each CPU core domain.
> +
> +properties:
> +  compatible:
> +    const: renesas,mfis-mbox

You need SoC specific compatibles, unless this is not SoC...

> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    description: the irq line

Drop, redundant. Can it be not a irq line?

> +    maxItems: 1
> +
> +  "#mbox-cells":
> +    const: 1
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - "#mbox-cells"
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +    mailbox: mfis_mbox@18842000  {


Please follow carefully DTS coding style. Also drop unnecessary label.

> +        compatible = "renesas,mfis-mbox";
> +        reg = <0x18842000 0x8>;
> +        interrupts = <GIC_SPI 4362 IRQ_TYPE_LEVEL_HIGH>;
> +        #mbox-cells = <1>;
> +    };


Best regards,
Krzysztof

Re: [PATCH 1/3] mailbox: remove unneeded double quotation

[Geert Uytterhoeven]

On Fri, 24 Oct 2025 at 08:22, Kuninori Morimoto
<kuninori.morimoto.gx@renesas.com> wrote:
> It makes Kconfig strange. fix it.
>
> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH 2/3] mailbox: renesas: Support MFIS mailbox driver

[Geert Uytterhoeven]

Hi Morimoto-san,

On Fri, 24 Oct 2025 at 08:22, Kuninori Morimoto
<kuninori.morimoto.gx@renesas.com> wrote:
> From: Masashi Ozaki <masashi.ozaki.te@renesas.com>
>
> Add Renesas MFIS mailbox driver for R8A78000 (X5H)
>
> Signed-off-by: Masashi Ozaki <masashi.ozaki.te@renesas.com>
> Signed-off-by: Vinh Nguyen <vinh.nguyen.xz@renesas.com>
> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>

Thanks for your patch!

> --- /dev/null
> +++ b/drivers/mailbox/rcar-mfis-mailbox.c
> @@ -0,0 +1,137 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Renesas MFIS (Multifunctional Interface) Mailbox Driver
> + *
> + * Copyright (c) 2025, Renesas Electronics Corporation. All rights reserved.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/interrupt.h>
> +#include <linux/mailbox_controller.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +
> +static int mfis_send_data(struct mbox_chan *link, void *data)
> +{
> +       void __iomem *reg = link->con_priv;
> +
> +       /*Trigger interrupt request to firmware(SCP)*/
> +       iowrite32(0x1, reg);
> +
> +       return 0;
> +}
> +
> +static irqreturn_t mfis_rx_interrupt(int irq, void *data)
> +{
> +       struct mbox_chan *link = data;
> +       void __iomem *reg = link->con_priv;
> +
> +       mbox_chan_received_data(link, 0);
> +
> +       /* Clear interrupt register */
> +       iowrite32(0x0, reg);
> +
> +       return IRQ_HANDLED;
> +}
> +
> +static int mfis_startup(struct mbox_chan *link)
> +{
> +       struct mbox_controller *mbox = link->mbox;
> +       struct device *dev = mbox->dev;
> +       int irq;
> +       int ret;
> +
> +       irq = of_irq_get(dev->of_node, 0);
> +
> +       ret = request_irq(irq, mfis_rx_interrupt,
> +                         IRQF_SHARED, "mfis-mbox", link);
> +       if (ret) {
> +               dev_err(dev,
> +                       "Unable to acquire IRQ %d\n", irq);
> +               return ret;
> +       }

This looks a bit expensive to do on each and every client request ...

> +       return 0;
> +}
> +
> +static void mfis_shutdown(struct mbox_chan *link)
> +{
> +       struct mbox_controller *mbox = link->mbox;
> +       struct device *dev = mbox->dev;
> +       int irq;
> +
> +       irq = of_irq_get(dev->of_node, 0);

... and release.  Just store and request the irq in .probe().

> +
> +       free_irq(irq, link);
> +}
> +
> +static bool mfis_last_tx_done(struct mbox_chan *link)
> +{
> +       return true;
> +}
> +
> +static const struct mbox_chan_ops mfis_chan_ops = {
> +       .send_data      = mfis_send_data,
> +       .startup        = mfis_startup,
> +       .shutdown       = mfis_shutdown,
> +       .last_tx_done   = mfis_last_tx_done
> +};
> +
> +static int mfis_mbox_probe(struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       struct mbox_controller *mbox;
> +       void __iomem *reg;
> +       int ret, count = 2, i;

unsigned int i (and count, but I doubt you need it)

> +
> +       mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
> +       if (!mbox)
> +               return -ENOMEM;
> +
> +       mbox->chans = devm_kcalloc(dev, count, sizeof(*mbox->chans), GFP_KERNEL);
> +       if (!mbox->chans)
> +               return -ENOMEM;

You can combine this into a single allocation, and provide space for
driver-specific data (e.g. irq), by using a driver-private structure:

    struct mfis_priv {
            struct mbox_controller mbox;
            struct mbox_chan channels[2];
            int irq;
    };

Where needed, you can convert from a struct mbox_controller pointer
to a struct mfis_priv pointer using containter_of().

> +
> +       reg = devm_platform_ioremap_resource(pdev, i);
> +       if (IS_ERR(reg))
> +               return PTR_ERR(reg);
> +
> +       for (i = 0; i < count; i++) {
> +               mbox->chans[i].mbox     = mbox;
> +               mbox->chans[i].con_priv = reg + ((1 - i) * 4);
> +       }
> +
> +       mbox->txdone_poll       = true;
> +       mbox->txdone_irq        = false;
> +       mbox->txpoll_period     = 1;
> +       mbox->num_chans         = count;
> +       mbox->ops               = &mfis_chan_ops;
> +       mbox->dev               = dev;
> +
> +       ret = mbox_controller_register(mbox);
> +       if (ret)
> +               return ret;
> +
> +       platform_set_drvdata(pdev, mbox);
> +       dev_info(dev, "MFIS mailbox is probed\n");
> +
> +       return 0;
> +}
> +
> +static const struct of_device_id mfis_mbox_of_match[] = {
> +       { .compatible = "renesas,mfis-mbox", },
> +       {},

Please no trailing comma after the sentinel.

> +};
> +MODULE_DEVICE_TABLE(of, mfis_mbox_of_match);
> +
> +static struct platform_driver mfis_mbox_driver = {
> +       .driver = {
> +               .name = "renesas-mfis-mbox",
> +               .of_match_table = mfis_mbox_of_match,
> +       },
> +       .probe  = mfis_mbox_probe,
> +};
> +module_platform_driver(mfis_mbox_driver);
> +MODULE_DESCRIPTION("Renesas MFIS mailbox driver");
> +MODULE_LICENSE("GPL v2");

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH 2/3] mailbox: renesas: Support MFIS mailbox driver

[Wolfram Sang]

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Hi Morimoto-san,

in addition to what the others already mentioned...

> +	help
> +	  This driver provides support for SCMI interface transport with
> +	  MFIS(Multifunctional Interface).
> +	  It is used to send short message between CPU cores and
> +	  SCP(System Control Processor).

Spaces after MFIS and SCP. But I would reword it because it can send
messages to the RT domain, too. Suggestion:

+	  This driver provides support for mailboxes of the MFIS
+	  (Multifunctional Interface) via the SCMI interface.
+	  It is used to send short message between different domains
+	  like AP, RT, and SCP.


> +
>  config RISCV_SBI_MPXY_MBOX
>  	tristate "RISC-V SBI Message Proxy (MPXY) Mailbox"
>  	depends on RISCV_SBI
> @@ -389,5 +398,4 @@ config RISCV_SBI_MPXY_MBOX
>  	  remote processor through the SBI implementation (M-mode firmware
>  	  or HS-mode hypervisor). Say Y here if you want to have this support.
>  	  If unsure say N.
> -
>  endif
> diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
> index 81820a4f55285..060a9c7f6727b 100644
> --- a/drivers/mailbox/Makefile
> +++ b/drivers/mailbox/Makefile
> @@ -27,6 +27,8 @@ obj-$(CONFIG_PL320_MBOX)	+= pl320-ipc.o
>  
>  obj-$(CONFIG_OMAP2PLUS_MBOX)	+= omap-mailbox.o
>  
> +obj-$(CONFIG_RCAR_MFIS_MBOX)	+= rcar-mfis-mailbox.o
> +
>  obj-$(CONFIG_ROCKCHIP_MBOX)	+= rockchip-mailbox.o
>  
>  obj-$(CONFIG_PCC)		+= pcc.o
> diff --git a/drivers/mailbox/rcar-mfis-mailbox.c b/drivers/mailbox/rcar-mfis-mailbox.c
> new file mode 100644
> index 0000000000000..54cabfa305eb4
> --- /dev/null
> +++ b/drivers/mailbox/rcar-mfis-mailbox.c
> @@ -0,0 +1,137 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Renesas MFIS (Multifunctional Interface) Mailbox Driver
> + *
> + * Copyright (c) 2025, Renesas Electronics Corporation. All rights reserved.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/interrupt.h>
> +#include <linux/mailbox_controller.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +
> +static int mfis_send_data(struct mbox_chan *link, void *data)
> +{
> +	void __iomem *reg = link->con_priv;
> +
> +	/*Trigger interrupt request to firmware(SCP)*/

Spaces before and after "*"

> +	iowrite32(0x1, reg);

#define instead of hardcoded value?

But I guess the real question here is: do we know already that the SCP
firmware will just react on the interrupt? We really do not need the 15
bits of data that goes with this register? Or the message register?

> +
> +	return 0;
> +}
> +
> +static irqreturn_t mfis_rx_interrupt(int irq, void *data)
> +{
> +	struct mbox_chan *link = data;
> +	void __iomem *reg = link->con_priv;
> +
> +	mbox_chan_received_data(link, 0);
> +
> +	/* Clear interrupt register */

I would drop this comment, but maybe others won't.

> +	iowrite32(0x0, reg);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int mfis_startup(struct mbox_chan *link)
> +{
> +	struct mbox_controller *mbox = link->mbox;
> +	struct device *dev = mbox->dev;
> +	int irq;
> +	int ret;
> +
> +	irq = of_irq_get(dev->of_node, 0);
> +
> +	ret = request_irq(irq, mfis_rx_interrupt,
> +			  IRQF_SHARED, "mfis-mbox", link);
> +	if (ret) {
> +		dev_err(dev,
> +			"Unable to acquire IRQ %d\n", irq);
> +		return ret;
> +	}
> +	return 0;
> +}
> +
> +static void mfis_shutdown(struct mbox_chan *link)
> +{
> +	struct mbox_controller *mbox = link->mbox;
> +	struct device *dev = mbox->dev;
> +	int irq;
> +
> +	irq = of_irq_get(dev->of_node, 0);
> +
> +	free_irq(irq, link);

Is it really necessary to free the irq here? We could simply disable it?

> +}
> +
> +static bool mfis_last_tx_done(struct mbox_chan *link)
> +{
> +	return true;
> +}
> +
> +static const struct mbox_chan_ops mfis_chan_ops = {
> +	.send_data	= mfis_send_data,
> +	.startup	= mfis_startup,
> +	.shutdown	= mfis_shutdown,
> +	.last_tx_done	= mfis_last_tx_done
> +};
> +
> +static int mfis_mbox_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct mbox_controller *mbox;
> +	void __iomem *reg;
> +	int ret, count = 2, i;

Why is count = 2? Doesn't X5H support 64 of them?

> +
> +	mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
> +	if (!mbox)
> +		return -ENOMEM;
> +
> +	mbox->chans = devm_kcalloc(dev, count, sizeof(*mbox->chans), GFP_KERNEL);
> +	if (!mbox->chans)
> +		return -ENOMEM;
> +
> +	reg = devm_platform_ioremap_resource(pdev, i);
> +	if (IS_ERR(reg))
> +		return PTR_ERR(reg);
> +
> +	for (i = 0; i < count; i++) {
> +		mbox->chans[i].mbox	= mbox;
> +		mbox->chans[i].con_priv	= reg + ((1 - i) * 4);

Why backwards ("1 - i")?

> +	}
> +
> +	mbox->txdone_poll	= true;
> +	mbox->txdone_irq	= false;
> +	mbox->txpoll_period	= 1;
> +	mbox->num_chans		= count;
> +	mbox->ops		= &mfis_chan_ops;
> +	mbox->dev		= dev;

Only one space before '='.

> +
> +	ret = mbox_controller_register(mbox);
> +	if (ret)
> +		return ret;
> +
> +	platform_set_drvdata(pdev, mbox);
> +	dev_info(dev, "MFIS mailbox is probed\n");
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id mfis_mbox_of_match[] = {
> +	{ .compatible = "renesas,mfis-mbox", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, mfis_mbox_of_match);
> +
> +static struct platform_driver mfis_mbox_driver = {
> +	.driver = {
> +		.name = "renesas-mfis-mbox",
> +		.of_match_table = mfis_mbox_of_match,
> +	},
> +	.probe	= mfis_mbox_probe,
> +};
> +module_platform_driver(mfis_mbox_driver);
> +MODULE_DESCRIPTION("Renesas MFIS mailbox driver");
> +MODULE_LICENSE("GPL v2");

"GPL" only.

But I guess we need a bit more information about the bigger picture of
this driver. Like, with which firmware was this used?

Happy hacking,

   Wolfram


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Re: [PATCH 3/3] dt-bindings: mailbox: Add Renesas MFIS Mailbox

[Kuninori Morimoto]

Hi Rob

> > Add device tree bindings for the Renesas Multifunctional Interface
> > (MFIS) a mailbox controller.
> >
> > Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
> > ---
> >  .../mailbox/renesas,mfis-mailbox.yaml         | 49 +++++++++++++++++++
> >  1 file changed, 49 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/mailbox/renesas,mfis-mailbox.yaml
> >
>
> My bot found errors running 'make dt_binding_check' on your patch:

Hmm... I can't reproduce the issue. What I'm missing ??

	> pip show dtschema
	Name: dtschema
	Version: 2025.8
	...

	> make dt_binding_check DT_SCHEMA_FILES=Documentation/devicetree/bindings/mailbox/renesas,mfis-mailbox.yaml
	SCHEMA  Documentation/devicetree/bindings/processed-schema.json
	CHKDT   /home/morimoto/.mydata/linux/Documentation/devicetree/bindings
	LINT    /home/morimoto/.mydata/linux/Documentation/devicetree/bindings
	DTEX    Documentation/devicetree/bindings/mailbox/renesas,mfis-mailbox.example.dts
	DTC [C] Documentation/devicetree/bindings/mailbox/renesas,mfis-mailbox.example.dtb
	>

Thank you for your help !!

Best regards
---
Kuninori Morimoto

Re: [PATCH 3/3] dt-bindings: mailbox: Add Renesas MFIS Mailbox

[Geert Uytterhoeven]

Hi Morimoto-san,

On Mon, 27 Oct 2025 at 05:57, Kuninori Morimoto
<kuninori.morimoto.gx@renesas.com> wrote:
> > > Add device tree bindings for the Renesas Multifunctional Interface
> > > (MFIS) a mailbox controller.
> > >
> > > Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
> > > ---
> > >  .../mailbox/renesas,mfis-mailbox.yaml         | 49 +++++++++++++++++++
> > >  1 file changed, 49 insertions(+)
> > >  create mode 100644 Documentation/devicetree/bindings/mailbox/renesas,mfis-mailbox.yaml
> > >
> >
> > My bot found errors running 'make dt_binding_check' on your patch:

> > from schema $id: http://devicetree.org/schemas/soc/renesas/renesas-soc.yaml
                                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

> Hmm... I can't reproduce the issue. What I'm missing ??
>
>         > pip show dtschema
>         Name: dtschema
>         Version: 2025.8
>         ...
>
>         > make dt_binding_check DT_SCHEMA_FILES=Documentation/devicetree/bindings/mailbox/renesas,mfis-mailbox.yaml

You are checking against the wrong bindings file.

However, I cannot trigger the warning by passing
DT_SCHEMA_FILES=Documentation/devicetree/bindings/soc/renesas/renesas-soc.yaml
instead.  I only see it when dropping the DT_SCHEMA_FILES parameter,
and thus running all checks.

If you are 100% sure you do not want an SoC-specific compatible
value, you can fix the warning by adding "renesas,mfis-mbox" to
renesas-soc.yaml.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH 3/3] dt-bindings: mailbox: Add Renesas MFIS Mailbox

[Kuninori Morimoto]

Hi Geert

> You are checking against the wrong bindings file.

Ah, OK thanks, I could reproduce the issue.
Will update files

# I couldn't notice about different file, because Renesas Mail server
# changes the URL for security reasons

Thank you for your help !!

Best regards
---
Kuninori Morimoto

Re: [PATCH 3/3] dt-bindings: mailbox: Add Renesas MFIS Mailbox

[Kuninori Morimoto]

Hi Geert

> > Hmm... I can't reproduce the issue. What I'm missing ??
(snip)
> You are checking against the wrong bindings file.
> 
> However, I cannot trigger the warning by passing
> DT_SCHEMA_FILES=Documentation/devicetree/bindings/soc/renesas/renesas-soc.yaml
> instead.  I only see it when dropping the DT_SCHEMA_FILES parameter,
> and thus running all checks.

Grr...

> If you are 100% sure you do not want an SoC-specific compatible
> value, you can fix the warning by adding "renesas,mfis-mbox" to
> renesas-soc.yaml.

It seems I need to.
In this case, should I create separate patch (= for renesas-soc,
for mailbox) ? or can I merge it into one ?

Thank you for your help !!

Best regards
---
Kuninori Morimoto

Re: [PATCH 3/3] dt-bindings: mailbox: Add Renesas MFIS Mailbox

[Geert Uytterhoeven]

Hi Morimoto-san,

On Wed, 29 Oct 2025 at 07:26, Kuninori Morimoto
<kuninori.morimoto.gx@renesas.com> wrote:
> > > Hmm... I can't reproduce the issue. What I'm missing ??
> (snip)
> > You are checking against the wrong bindings file.
> >
> > However, I cannot trigger the warning by passing
> > DT_SCHEMA_FILES=Documentation/devicetree/bindings/soc/renesas/renesas-soc.yaml
> > instead.  I only see it when dropping the DT_SCHEMA_FILES parameter,
> > and thus running all checks.
>
> Grr...
>
> > If you are 100% sure you do not want an SoC-specific compatible
> > value, you can fix the warning by adding "renesas,mfis-mbox" to
> > renesas-soc.yaml.
>
> It seems I need to.
> In this case, should I create separate patch (= for renesas-soc,
> for mailbox) ? or can I merge it into one ?

Changes for .../devicetree/bindings/soc/renesas/ go through the Renesas
(i.e. my) tree, changes to .../devicetree/bindings/mailbox/ go through
the mailbox tree.  Hence you need separate patches.

However, your v2 does have an SoC-specific compatible value, so you
don't need to change renesas-soc.yaml?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds