[PATCH v1 0/2] mailbox: Add MediaTek TinySYS Mailbox

[PATCH v1 0/2] mailbox: Add MediaTek TinySYS Mailbox

[AngeloGioacchino Del Regno]

This series adds support for the MediaTek TinySYS Mailbox, used for
message passing on ARM SCMI and for both the standard 0x10 SCMI and
the MediaTek TinySYS SCMI protocol.

This mailbox is similar to the standard MHU Mailbox, but with some
critical differences that are MediaTek-specific; for more information,
check the description for the commits in this series.

This mailbox is found in the new MT8196 Chromebook SoC and in the
MT6991 Dimensity 9400 SoC, other than slightly older chips like
MT6898 Dimensity 9300, the MT6985 Dimensity 9200 and similar.

Support for all of the mentioned SoCs is present in this series.

AngeloGioacchino Del Regno (2):
  dt-bindings: mailbox: Add MediaTek TinySYS MHU mailbox
  mailbox: Add MediaTek TinySYS MHU-like Mailbox

 .../mediatek,mt6985-tinysys-mhu-mbox.yaml     |  52 +++++
 drivers/mailbox/Kconfig                       |   9 +
 drivers/mailbox/Makefile                      |   2 +
 drivers/mailbox/mtk-tinysys-mailbox.c         | 196 ++++++++++++++++++
 4 files changed, 259 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/mediatek,mt6985-tinysys-mhu-mbox.yaml
 create mode 100644 drivers/mailbox/mtk-tinysys-mailbox.c

-- 
2.49.0

[PATCH v1 1/2] dt-bindings: mailbox: Add MediaTek TinySYS MHU mailbox

[AngeloGioacchino Del Regno]

Add a binding for the MediaTek TinySYS MHU mailbox, used for IPC
with the TinySYS hardware integrated in various MediaTek SoCs.

This mailbox handles a custom MHU enabling communication through
the TinySYS SCMI protocol.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 .../mediatek,mt6985-tinysys-mhu-mbox.yaml     | 52 +++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/mediatek,mt6985-tinysys-mhu-mbox.yaml

diff --git a/Documentation/devicetree/bindings/mailbox/mediatek,mt6985-tinysys-mhu-mbox.yaml b/Documentation/devicetree/bindings/mailbox/mediatek,mt6985-tinysys-mhu-mbox.yaml
new file mode 100644
index 000000000000..20fa5cb0ca0a
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/mediatek,mt6985-tinysys-mhu-mbox.yaml
@@ -0,0 +1,52 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mailbox/mediatek,mt6985-tinysys-mhu-mbox.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek TinySYS MHU mailbox
+
+maintainers:
+  - AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
+
+description:
+  This mailbox is used for Inter-Processor Communication (IPC) with the
+  TinySYS hardware integrated in various MediaTek SoCs and handles custom
+  Message Handling Unit (MHU) enabling communication through the TinySYS
+  SCMI protocol.
+
+properties:
+  compatible:
+    enum:
+      - mediatek,mt6985-tinysys-mhu-mbox
+      - mediatek,mt6989-tinysys-mhu-mbox
+      - mediatek,mt8196-tinysys-mhu-mbox
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  "#mbox-cells":
+    const: 0
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - "#mbox-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    tinysys_mbox0: mailbox@1c351000 {
+        compatible = "mediatek,mt6985-tinysys-mhu-mbox";
+        reg = <0x1c351000 0x1000>;
+        interrupts = <GIC_SPI 341 IRQ_TYPE_LEVEL_HIGH 0>;
+        #mbox-cells = <0>;
+    };
-- 
2.49.0

[PATCH v1 2/2] mailbox: Add MediaTek TinySYS MHU-like Mailbox

[AngeloGioacchino Del Regno]

Add the MediaTek TinySYS mailbox, used for IPC with the TinySYS
MCU that is integrated in variousSoCs, enabling communication
with remote processors that use the MediaTek IPIC framework
through the TinySYS SCMI protocol.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 drivers/mailbox/Kconfig               |   9 ++
 drivers/mailbox/Makefile              |   2 +
 drivers/mailbox/mtk-tinysys-mailbox.c | 196 ++++++++++++++++++++++++++
 3 files changed, 207 insertions(+)
 create mode 100644 drivers/mailbox/mtk-tinysys-mailbox.c

diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index 68eeed660a4a..35149110cb3a 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -285,6 +285,15 @@ config MTK_CMDQ_MBOX
 	  critical time limitation, such as updating display configuration
 	  during the vblank.
 
+config MTK_TINYSYS_MBOX
+	tristate "MediaTek TINYSYS Mailbox Support"
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+	help
+	  The MediaTek TinySYS mailbox is used to communicate with remote
+	  processors based on the MediaTek IPIC framework.
+	  Say yes here to add support for the MediaTek TinySYS mailbox
+	  driver.
+
 config ZYNQMP_IPI_MBOX
 	tristate "Xilinx ZynqMP IPI Mailbox"
 	depends on ARCH_ZYNQMP && OF
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index 13a3448b3271..415eb1d9ed47 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -61,6 +61,8 @@ obj-$(CONFIG_MTK_ADSP_MBOX)	+= mtk-adsp-mailbox.o
 
 obj-$(CONFIG_MTK_CMDQ_MBOX)	+= mtk-cmdq-mailbox.o
 
+obj-$(CONFIG_MTK_TINYSYS_MBOX)	+= mtk-tinysys-mailbox.o
+
 obj-$(CONFIG_ZYNQMP_IPI_MBOX)	+= zynqmp-ipi-mailbox.o
 
 obj-$(CONFIG_SUN6I_MSGBOX)	+= sun6i-msgbox.o
diff --git a/drivers/mailbox/mtk-tinysys-mailbox.c b/drivers/mailbox/mtk-tinysys-mailbox.c
new file mode 100644
index 000000000000..ec84951230e6
--- /dev/null
+++ b/drivers/mailbox/mtk-tinysys-mailbox.c
@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2021 MediaTek Inc.
+ * Copyright (c) 2025 Collabora Ltd
+ *                    AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_controller.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/soc/mediatek/mtk_sip_svc.h>
+
+#define MTK_SIP_TINYSYS_SSPM_CONTROL	MTK_SIP_SMC_CMD(0x53c)
+#define MTK_TINYSYS_SSPM_OP_MBOX_CLR	0
+#define MTK_TINYSYS_SSPM_OP_MD2SPM_CLR	1
+
+#define INTR_SET_OFS	0x0
+#define INTR_CLR_OFS	0x4
+
+struct mtk_tinysys_mhu_mbox_pdata {
+	bool is_secure_mbox;
+	bool notify_spm;
+};
+
+struct mtk_tinysys_mhu_mbox {
+	void __iomem *base;
+	int irq;
+	const struct mtk_tinysys_mhu_mbox_pdata *pdata;
+	struct mbox_controller mbox;
+};
+
+static inline struct mtk_tinysys_mhu_mbox *to_mtk_tinysys_mhu_mbox(struct mbox_controller *mbox)
+{
+	return container_of(mbox, struct mtk_tinysys_mhu_mbox, mbox);
+}
+
+static irqreturn_t mtk_tinysys_mhu_mbox_irq(int irq, void *data)
+{
+	u32 val;
+	struct arm_smccc_res res;
+	struct mbox_chan *chan = data;
+	struct mtk_tinysys_mhu_mbox *priv = to_mtk_tinysys_mhu_mbox(chan->mbox);
+
+	val = readl_relaxed(priv->base + INTR_CLR_OFS);
+	if (!val)
+		return IRQ_NONE;
+
+	if (priv->pdata->is_secure_mbox) {
+		/* Can't fail: ignore res.a0 checks */
+		arm_smccc_smc(MTK_SIP_TINYSYS_SSPM_CONTROL,
+			      MTK_TINYSYS_SSPM_OP_MBOX_CLR,
+			      priv->irq, 0, 0, 0, 0, 0, &res);
+	} else {
+		writel(1, priv->base + INTR_CLR_OFS);
+	}
+
+	mbox_chan_received_data(chan, (void *)&val);
+
+	if (priv->pdata->notify_spm)
+		arm_smccc_smc(MTK_SIP_TINYSYS_SSPM_CONTROL,
+			      MTK_TINYSYS_SSPM_OP_MD2SPM_CLR,
+			      priv->irq, 0, 0, 0, 0, 0, &res);
+	return IRQ_HANDLED;
+}
+
+static bool mtk_tinysys_mhu_mbox_last_tx_done(struct mbox_chan *chan)
+{
+	struct mtk_tinysys_mhu_mbox *priv = to_mtk_tinysys_mhu_mbox(chan->mbox);
+	u32 val = readl_relaxed(priv->base + INTR_SET_OFS);
+
+	return val == 0;
+}
+
+static int mtk_tinysys_mhu_mbox_send_data(struct mbox_chan *chan, void *data)
+{
+	struct mtk_tinysys_mhu_mbox *priv = to_mtk_tinysys_mhu_mbox(chan->mbox);
+	u32 *arg = data;
+
+	writel_relaxed(*arg, priv->base + INTR_SET_OFS);
+
+	return 0;
+}
+
+static int mtk_tinysys_mhu_mbox_startup(struct mbox_chan *chan)
+{
+	struct mtk_tinysys_mhu_mbox *priv = to_mtk_tinysys_mhu_mbox(chan->mbox);
+
+	irq_clear_status_flags(priv->irq, IRQ_NOAUTOEN);
+	enable_irq(priv->irq);
+
+	return 0;
+}
+
+static void mtk_tinysys_mhu_mbox_shutdown(struct mbox_chan *chan)
+{
+	struct mtk_tinysys_mhu_mbox *priv = to_mtk_tinysys_mhu_mbox(chan->mbox);
+
+	disable_irq(priv->irq);
+}
+
+static const struct mbox_chan_ops tinysys_mbox_chan_ops = {
+	.send_data = mtk_tinysys_mhu_mbox_send_data,
+	.startup = mtk_tinysys_mhu_mbox_startup,
+	.shutdown = mtk_tinysys_mhu_mbox_shutdown,
+	.last_tx_done = mtk_tinysys_mhu_mbox_last_tx_done,
+};
+
+static int mtk_tinysys_mhu_mbox_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mtk_tinysys_mhu_mbox *priv;
+	struct mbox_controller *mbox;
+	int ret;
+
+	/* Allocate memory for device */
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	priv->irq = platform_get_irq(pdev, 0);
+	if (priv->irq < 0)
+		return priv->irq;
+
+	priv->pdata = device_get_match_data(dev);
+	if (!priv->pdata)
+		return -EINVAL;
+
+	mbox = &priv->mbox;
+	mbox->dev = dev;
+	mbox->ops = &tinysys_mbox_chan_ops;
+	mbox->txdone_irq = false;
+	mbox->txdone_poll = true;
+	mbox->txpoll_period = 1;
+	mbox->num_chans = 1;
+	mbox->chans = devm_kzalloc(dev, sizeof(*mbox->chans), GFP_KERNEL);
+	if (!mbox->chans)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, priv);
+
+	irq_set_status_flags(priv->irq, IRQ_NOAUTOEN);
+	ret = devm_request_irq(dev, priv->irq, mtk_tinysys_mhu_mbox_irq,
+			       IRQF_TRIGGER_NONE, dev_name(dev), mbox->chans);
+	if (ret < 0)
+		return ret;
+
+	ret = devm_mbox_controller_register(dev, &priv->mbox);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to register mailbox\n");
+
+	return 0;
+}
+
+static const struct mtk_tinysys_mhu_mbox_pdata mt6985_tsmhu_mbox_cfg = {
+	/* Unsecured mailbox, no SPM notification */
+};
+
+static const struct mtk_tinysys_mhu_mbox_pdata mt6989_tsmhu_mbox_cfg = {
+	.is_secure_mbox = true,
+};
+
+static const struct mtk_tinysys_mhu_mbox_pdata mt8196_tsmhu_mbox_cfg = {
+	.notify_spm = true,
+};
+
+static const struct of_device_id mtk_tinysys_mhu_mbox_of_match[] = {
+	{ .compatible = "mediatek,mt6985-tinysys-mhu-mbox", .data = &mt6985_tsmhu_mbox_cfg },
+	{ .compatible = "mediatek,mt6989-tinysys-mhu-mbox", .data = &mt6989_tsmhu_mbox_cfg },
+	{ .compatible = "mediatek,mt8196-tinysys-mhu-mbox", .data = &mt8196_tsmhu_mbox_cfg },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mtk_tinysys_mhu_mbox_of_match);
+
+static struct platform_driver mtk_tinysys_mhu_mbox_drv = {
+	.probe = mtk_tinysys_mhu_mbox_probe,
+	.driver = {
+		.name = "mtk-tinysys-mhu-mbox",
+		.of_match_table = mtk_tinysys_mhu_mbox_of_match,
+	}
+};
+module_platform_driver(mtk_tinysys_mhu_mbox_drv);
+
+MODULE_AUTHOR("AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>");
+MODULE_DESCRIPTION("MediaTek TinySYS Mailbox Controller");
+MODULE_LICENSE("GPL");
-- 
2.49.0

Re: [PATCH v1 2/2] mailbox: Add MediaTek TinySYS MHU-like Mailbox

[kernel test robot]

Hi AngeloGioacchino,

kernel test robot noticed the following build errors:

[auto build test ERROR on jassibrar-mailbox/for-next]
[also build test ERROR on robh/for-next soc/for-next linus/master v6.16-rc3 next-20250623]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/AngeloGioacchino-Del-Regno/dt-bindings-mailbox-Add-MediaTek-TinySYS-MHU-mailbox/20250623-201139
base:   https://git.kernel.org/pub/scm/linux/kernel/git/jassibrar/mailbox.git for-next
patch link:    https://lore.kernel.org/r/20250623120127.109237-3-angelogioacchino.delregno%40collabora.com
patch subject: [PATCH v1 2/2] mailbox: Add MediaTek TinySYS MHU-like Mailbox
config: i386-allmodconfig (https://download.01.org/0day-ci/archive/20250624/202506241946.HEKwafHB-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250624/202506241946.HEKwafHB-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202506241946.HEKwafHB-lkp@intel.com/

All errors (new ones prefixed by >>):

   drivers/mailbox/mtk-tinysys-mailbox.c: In function 'mtk_tinysys_mhu_mbox_startup':
>> drivers/mailbox/mtk-tinysys-mailbox.c:95:9: error: implicit declaration of function 'irq_clear_status_flags' [-Werror=implicit-function-declaration]
      95 |         irq_clear_status_flags(priv->irq, IRQ_NOAUTOEN);
         |         ^~~~~~~~~~~~~~~~~~~~~~
>> drivers/mailbox/mtk-tinysys-mailbox.c:95:43: error: 'IRQ_NOAUTOEN' undeclared (first use in this function); did you mean 'IRQF_NO_AUTOEN'?
      95 |         irq_clear_status_flags(priv->irq, IRQ_NOAUTOEN);
         |                                           ^~~~~~~~~~~~
         |                                           IRQF_NO_AUTOEN
   drivers/mailbox/mtk-tinysys-mailbox.c:95:43: note: each undeclared identifier is reported only once for each function it appears in
   drivers/mailbox/mtk-tinysys-mailbox.c: In function 'mtk_tinysys_mhu_mbox_probe':
>> drivers/mailbox/mtk-tinysys-mailbox.c:152:9: error: implicit declaration of function 'irq_set_status_flags' [-Werror=implicit-function-declaration]
     152 |         irq_set_status_flags(priv->irq, IRQ_NOAUTOEN);
         |         ^~~~~~~~~~~~~~~~~~~~
   drivers/mailbox/mtk-tinysys-mailbox.c:152:41: error: 'IRQ_NOAUTOEN' undeclared (first use in this function); did you mean 'IRQF_NO_AUTOEN'?
     152 |         irq_set_status_flags(priv->irq, IRQ_NOAUTOEN);
         |                                         ^~~~~~~~~~~~
         |                                         IRQF_NO_AUTOEN
   cc1: some warnings being treated as errors


vim +/irq_clear_status_flags +95 drivers/mailbox/mtk-tinysys-mailbox.c

    90	
    91	static int mtk_tinysys_mhu_mbox_startup(struct mbox_chan *chan)
    92	{
    93		struct mtk_tinysys_mhu_mbox *priv = to_mtk_tinysys_mhu_mbox(chan->mbox);
    94	
  > 95		irq_clear_status_flags(priv->irq, IRQ_NOAUTOEN);
    96		enable_irq(priv->irq);
    97	
    98		return 0;
    99	}
   100	
   101	static void mtk_tinysys_mhu_mbox_shutdown(struct mbox_chan *chan)
   102	{
   103		struct mtk_tinysys_mhu_mbox *priv = to_mtk_tinysys_mhu_mbox(chan->mbox);
   104	
   105		disable_irq(priv->irq);
   106	}
   107	
   108	static const struct mbox_chan_ops tinysys_mbox_chan_ops = {
   109		.send_data = mtk_tinysys_mhu_mbox_send_data,
   110		.startup = mtk_tinysys_mhu_mbox_startup,
   111		.shutdown = mtk_tinysys_mhu_mbox_shutdown,
   112		.last_tx_done = mtk_tinysys_mhu_mbox_last_tx_done,
   113	};
   114	
   115	static int mtk_tinysys_mhu_mbox_probe(struct platform_device *pdev)
   116	{
   117		struct device *dev = &pdev->dev;
   118		struct mtk_tinysys_mhu_mbox *priv;
   119		struct mbox_controller *mbox;
   120		int ret;
   121	
   122		/* Allocate memory for device */
   123		priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
   124		if (!priv)
   125			return -ENOMEM;
   126	
   127		priv->base = devm_platform_ioremap_resource(pdev, 0);
   128		if (IS_ERR(priv->base))
   129			return PTR_ERR(priv->base);
   130	
   131		priv->irq = platform_get_irq(pdev, 0);
   132		if (priv->irq < 0)
   133			return priv->irq;
   134	
   135		priv->pdata = device_get_match_data(dev);
   136		if (!priv->pdata)
   137			return -EINVAL;
   138	
   139		mbox = &priv->mbox;
   140		mbox->dev = dev;
   141		mbox->ops = &tinysys_mbox_chan_ops;
   142		mbox->txdone_irq = false;
   143		mbox->txdone_poll = true;
   144		mbox->txpoll_period = 1;
   145		mbox->num_chans = 1;
   146		mbox->chans = devm_kzalloc(dev, sizeof(*mbox->chans), GFP_KERNEL);
   147		if (!mbox->chans)
   148			return -ENOMEM;
   149	
   150		platform_set_drvdata(pdev, priv);
   151	
 > 152		irq_set_status_flags(priv->irq, IRQ_NOAUTOEN);
   153		ret = devm_request_irq(dev, priv->irq, mtk_tinysys_mhu_mbox_irq,
   154				       IRQF_TRIGGER_NONE, dev_name(dev), mbox->chans);
   155		if (ret < 0)
   156			return ret;
   157	
   158		ret = devm_mbox_controller_register(dev, &priv->mbox);
   159		if (ret)
   160			return dev_err_probe(dev, ret, "Failed to register mailbox\n");
   161	
   162		return 0;
   163	}
   164	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v1 1/2] dt-bindings: mailbox: Add MediaTek TinySYS MHU mailbox

[Rob Herring (Arm)]

On Mon, 23 Jun 2025 14:01:26 +0200, AngeloGioacchino Del Regno wrote:
> Add a binding for the MediaTek TinySYS MHU mailbox, used for IPC
> with the TinySYS hardware integrated in various MediaTek SoCs.
> 
> This mailbox handles a custom MHU enabling communication through
> the TinySYS SCMI protocol.
> 
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ---
>  .../mediatek,mt6985-tinysys-mhu-mbox.yaml     | 52 +++++++++++++++++++
>  1 file changed, 52 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mailbox/mediatek,mt6985-tinysys-mhu-mbox.yaml
> 

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>