Add mtk-vcp-mailbox driver to support the communication with
VCP remote microprocessor.
Signed-off-by: Jjian Zhou <jjian.zhou@mediatek.com>
---
drivers/mailbox/Kconfig | 9 ++
drivers/mailbox/Makefile | 2 +
drivers/mailbox/mtk-vcp-mailbox.c | 174 ++++++++++++++++++++++++
include/linux/mailbox/mtk-vcp-mailbox.h | 32 +++++
4 files changed, 217 insertions(+)
create mode 100644 drivers/mailbox/mtk-vcp-mailbox.c
create mode 100644 include/linux/mailbox/mtk-vcp-mailbox.h
diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index 02432d4a5ccd..c28bdb855663 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -294,6 +294,15 @@ config MTK_CMDQ_MBOX
critical time limitation, such as updating display configuration
during the vblank.
+config MTK_VCP_MBOX
+ tristate "MediaTek VCP Mailbox Support"
+ depends on ARCH_MEDIATEK || COMPILE_TEST
+ help
+ Say yes here to add support for the MediaTek VCP mailbox driver.
+ The mailbox implementation provides access from the application
+ processor to Video Companion Processor Unit.
+ If unsure say N.
+
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 98a68f838486..07278871d254 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -63,6 +63,8 @@ obj-$(CONFIG_MTK_ADSP_MBOX) += mtk-adsp-mailbox.o
obj-$(CONFIG_MTK_CMDQ_MBOX) += mtk-cmdq-mailbox.o
+obj-$(CONFIG_MTK_VCP_MBOX) += mtk-vcp-mailbox.o
+
obj-$(CONFIG_ZYNQMP_IPI_MBOX) += zynqmp-ipi-mailbox.o
obj-$(CONFIG_SUN6I_MSGBOX) += sun6i-msgbox.o
diff --git a/drivers/mailbox/mtk-vcp-mailbox.c b/drivers/mailbox/mtk-vcp-mailbox.c
new file mode 100644
index 000000000000..6f48215896d2
--- /dev/null
+++ b/drivers/mailbox/mtk-vcp-mailbox.c
@@ -0,0 +1,174 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2025 MediaTek Corporation. All rights reserved.
+ * Author: Jjian Zhou <jjian.zhou.@mediatek.com>
+ */
+
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_controller.h>
+#include <linux/mailbox/mtk-vcp-mailbox.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+struct mtk_vcp_mbox_priv {
+ void __iomem *base;
+ struct device *dev;
+ struct mbox_controller mbox;
+ const struct mtk_vcp_mbox_cfg *cfg;
+ struct mtk_ipi_info ipi_recv;
+};
+
+struct mtk_vcp_mbox_cfg {
+ u32 set_in;
+ u32 clr_out;
+};
+
+static inline struct mtk_vcp_mbox_priv *get_mtk_vcp_mbox_priv(struct mbox_controller *mbox)
+{
+ return container_of(mbox, struct mtk_vcp_mbox_priv, mbox);
+}
+
+static irqreturn_t mtk_vcp_mbox_irq_thread(int irq, void *data)
+{
+ struct mbox_chan *chan = data;
+ struct mtk_vcp_mbox_priv *priv = get_mtk_vcp_mbox_priv(chan->mbox);
+
+ /* get irq status */
+ priv->ipi_recv.irq_status = readl(priv->base + priv->cfg->clr_out);
+
+ __ioread32_copy(priv->ipi_recv.msg, priv->base, MBOX_SLOT_MAX_SIZE / 4);
+
+ mbox_chan_received_data(chan, &priv->ipi_recv);
+
+ /* clear irq status */
+ writel(priv->ipi_recv.irq_status, priv->base + priv->cfg->clr_out);
+
+ return IRQ_HANDLED;
+}
+
+static struct mbox_chan *mtk_vcp_mbox_xlate(struct mbox_controller *mbox,
+ const struct of_phandle_args *sp)
+{
+ if (sp->args_count)
+ return NULL;
+
+ return mbox->chans;
+}
+
+static int mtk_vcp_mbox_send_data(struct mbox_chan *chan, void *data)
+{
+ struct mtk_vcp_mbox_priv *priv = get_mtk_vcp_mbox_priv(chan->mbox);
+ struct mtk_ipi_info *ipi_info = data;
+ u32 status;
+
+ if (!ipi_info->msg) {
+ dev_err(priv->dev, "msg buffer is NULL.\n");
+ return -EINVAL;
+ }
+
+ status = readl(priv->base + priv->cfg->set_in) & BIT(ipi_info->index);
+ if (status) {
+ dev_warn(priv->dev, "mailbox IPI %d is busy.\n", ipi_info->id);
+ return -EBUSY;
+ }
+
+ if (ipi_info->slot_ofs + ipi_info->len > MBOX_SLOT_MAX_SIZE)
+ return -EINVAL;
+ __iowrite32_copy(priv->base + ipi_info->slot_ofs, ipi_info->msg,
+ ipi_info->len);
+
+ writel(BIT(ipi_info->index), priv->base + priv->cfg->set_in);
+
+ return 0;
+}
+
+static bool mtk_vcp_mbox_last_tx_done(struct mbox_chan *chan)
+{
+ struct mtk_ipi_info *ipi_info = chan->active_req;
+ struct mtk_vcp_mbox_priv *priv = get_mtk_vcp_mbox_priv(chan->mbox);
+
+ return !(readl(priv->base + priv->cfg->set_in) & BIT(ipi_info->index));
+}
+
+static const struct mbox_chan_ops mtk_vcp_mbox_chan_ops = {
+ .send_data = mtk_vcp_mbox_send_data,
+ .last_tx_done = mtk_vcp_mbox_last_tx_done,
+};
+
+static int mtk_vcp_mbox_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct mtk_vcp_mbox_priv *priv;
+ struct mbox_controller *mbox;
+ int ret, irq;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->dev = dev;
+ mbox = &priv->mbox;
+ mbox->dev = dev;
+ mbox->ops = &mtk_vcp_mbox_chan_ops;
+ mbox->txdone_irq = false;
+ mbox->txdone_poll = true;
+ mbox->of_xlate = mtk_vcp_mbox_xlate;
+ mbox->num_chans = 1;
+ mbox->chans = devm_kzalloc(dev, sizeof(*mbox->chans), GFP_KERNEL);
+ if (!mbox->chans)
+ return -ENOMEM;
+
+ priv->ipi_recv.msg = devm_kzalloc(dev, MBOX_SLOT_MAX_SIZE, GFP_KERNEL);
+ if (!priv->ipi_recv.msg)
+ return -ENOMEM;
+
+ priv->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+
+ priv->cfg = of_device_get_match_data(dev);
+ if (!priv->cfg)
+ return -EINVAL;
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+
+ ret = devm_request_threaded_irq(dev, irq, NULL,
+ mtk_vcp_mbox_irq_thread, IRQF_ONESHOT,
+ dev_name(dev), mbox->chans);
+ if (ret < 0)
+ return ret;
+
+ platform_set_drvdata(pdev, priv);
+
+ return devm_mbox_controller_register(dev, &priv->mbox);
+}
+
+static const struct mtk_vcp_mbox_cfg mt8196_cfg = {
+ .set_in = 0x100,
+ .clr_out = 0x10C,
+};
+
+static const struct of_device_id mtk_vcp_mbox_of_match[] = {
+ { .compatible = "mediatek,mt8196-vcp-mbox", .data = &mt8196_cfg },
+ {},
+};
+MODULE_DEVICE_TABLE(of, mtk_vcp_mbox_of_match);
+
+static struct platform_driver mtk_vcp_mbox_driver = {
+ .probe = mtk_vcp_mbox_probe,
+ .driver = {
+ .name = "mtk_vcp_mbox",
+ .of_match_table = mtk_vcp_mbox_of_match,
+ },
+};
+module_platform_driver(mtk_vcp_mbox_driver);
+
+MODULE_AUTHOR("Jjian Zhou <jjian.zhou@mediatek.com>");
+MODULE_DESCRIPTION("MTK VCP Mailbox Controller");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/mailbox/mtk-vcp-mailbox.h b/include/linux/mailbox/mtk-vcp-mailbox.h
new file mode 100644
index 000000000000..143fb0d06e30
--- /dev/null
+++ b/include/linux/mailbox/mtk-vcp-mailbox.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
+/*
+ * Copyright (c) 2025 MediaTek Inc.
+ */
+
+#ifndef __MTK_VCP_MAILBOX_H__
+#define __MTK_VCP_MAILBOX_H__
+
+#define MBOX_SLOT_MAX_SIZE 0x100 /* mbox max slot size */
+
+/**
+ * struct mtk_ipi_info - mailbox message info for mtk-vcp-mailbox
+ * @msg: The share buffer between IPC and mailbox driver
+ * @len: Message length
+ * @id: This is for identification purposes and not actually used
+ * by the mailbox hardware.
+ * @index: The signal number of the mailbox message.
+ * @slot_ofs: Data slot offset.
+ * @irq_status: Captures incoming signals for the RX path.
+ *
+ * It is used between IPC with mailbox driver.
+ */
+struct mtk_ipi_info {
+ void *msg;
+ u32 len;
+ u32 id;
+ u32 index;
+ u32 slot_ofs;
+ u32 irq_status;
+};
+
+#endif
--
2.46.0On Thu, Aug 21, 2025 at 9:12 PM Jjian Zhou <jjian.zhou@mediatek.com> wrote:
.....
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +struct mtk_vcp_mbox_priv {
Maybe 'mtk_vcp_mbox' is a more appropriate name ?
> + void __iomem *base;
> + struct device *dev;
> + struct mbox_controller mbox;
> + const struct mtk_vcp_mbox_cfg *cfg;
> + struct mtk_ipi_info ipi_recv;
Maybe also have "struct mbox_chan chan[1]; " so that you don't have to
allocate one during the probe.
Also if you have "struct mbox_controller mbox;" as the first member,
you could simply typecast that to get this structure.
Something like "struct mpfs_mbox" in mailbox-mpfs.c
....
> +
> +static struct mbox_chan *mtk_vcp_mbox_xlate(struct mbox_controller *mbox,
> + const struct of_phandle_args *sp)
> +{
> + if (sp->args_count)
> + return NULL;
> +
> + return mbox->chans;
return &mbox->chans[0] seems better.
thnx
On Thu, 2025-09-18 at 18:50 -0500, Jassi Brar wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
>
>
> On Thu, Aug 21, 2025 at 9:12 PM Jjian Zhou <jjian.zhou@mediatek.com>
> wrote:
>
> .....
>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/slab.h>
> > +
> > +struct mtk_vcp_mbox_priv {
>
> Maybe 'mtk_vcp_mbox' is a more appropriate name ?
>
> > + void __iomem *base;
> > + struct device *dev;
> > + struct mbox_controller mbox;
> > + const struct mtk_vcp_mbox_cfg *cfg;
> > + struct mtk_ipi_info ipi_recv;
>
> Maybe also have "struct mbox_chan chan[1]; " so that you don't have
> to
> allocate one during the probe.
> Also if you have "struct mbox_controller mbox;" as the first member,
> you could simply typecast that to get this structure.
> Something like "struct mpfs_mbox" in mailbox-mpfs.c
>
ERROR:FLEXIBLE_ARRAY: Use C99 flexible arrays - see
https://docs.kernel.org/process/deprecated.html#zero-length-and-one-element-arrays
#81: FILE: drivers/mailbox/mtk-vcp-mailbox.c:24:
+ struct mbox_chan chans[1];
+};
Can we ignore this error?
> ....
> > +
> > +static struct mbox_chan *mtk_vcp_mbox_xlate(struct mbox_controller
> > *mbox,
> > + const struct
> > of_phandle_args *sp)
> > +{
> > + if (sp->args_count)
> > + return NULL;
> > +
> > + return mbox->chans;
>
> return &mbox->chans[0] seems better.
>
> thnx
On Tue, Sep 23, 2025 at 1:46 AM Jjian Zhou (周建) <Jjian.Zhou@mediatek.com> wrote:
>
> On Thu, 2025-09-18 at 18:50 -0500, Jassi Brar wrote:
> > External email : Please do not click links or open attachments until
> > you have verified the sender or the content.
> >
> >
> > On Thu, Aug 21, 2025 at 9:12 PM Jjian Zhou <jjian.zhou@mediatek.com>
> > wrote:
> >
> > .....
> >
> > > +#include <linux/module.h>
> > > +#include <linux/of.h>
> > > +#include <linux/platform_device.h>
> > > +#include <linux/slab.h>
> > > +
> > > +struct mtk_vcp_mbox_priv {
> >
> > Maybe 'mtk_vcp_mbox' is a more appropriate name ?
> >
> > > + void __iomem *base;
> > > + struct device *dev;
> > > + struct mbox_controller mbox;
> > > + const struct mtk_vcp_mbox_cfg *cfg;
> > > + struct mtk_ipi_info ipi_recv;
> >
> > Maybe also have "struct mbox_chan chan[1]; " so that you don't have
> > to
> > allocate one during the probe.
> > Also if you have "struct mbox_controller mbox;" as the first member,
> > you could simply typecast that to get this structure.
> > Something like "struct mpfs_mbox" in mailbox-mpfs.c
> >
>
>
> ERROR:FLEXIBLE_ARRAY: Use C99 flexible arrays - see
> https://docs.kernel.org/process/deprecated.html#zero-length-and-one-element-arrays
> #81: FILE: drivers/mailbox/mtk-vcp-mailbox.c:24:
> + struct mbox_chan chans[1];
> +};
>
> Can we ignore this error?
>
It seems single element style is deprecated. While we know what we are
doing, let us placate that error by
struct mbox_chan mch;
struct mbox_chan chans[];
and set chans = &mch
On Tue, 2025-09-23 at 08:11 -0500, Jassi Brar wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
>
>
> On Tue, Sep 23, 2025 at 1:46 AM Jjian Zhou (周建) <
> Jjian.Zhou@mediatek.com> wrote:
> >
> > On Thu, 2025-09-18 at 18:50 -0500, Jassi Brar wrote:
> > > External email : Please do not click links or open attachments
> > > until
> > > you have verified the sender or the content.
> > >
> > >
> > > On Thu, Aug 21, 2025 at 9:12 PM Jjian Zhou <
> > > jjian.zhou@mediatek.com>
> > > wrote:
> > >
> > > .....
> > >
> > > > +#include <linux/module.h>
> > > > +#include <linux/of.h>
> > > > +#include <linux/platform_device.h>
> > > > +#include <linux/slab.h>
> > > > +
> > > > +struct mtk_vcp_mbox_priv {
> > >
> > > Maybe 'mtk_vcp_mbox' is a more appropriate name ?
> > >
> > > > + void __iomem *base;
> > > > + struct device *dev;
> > > > + struct mbox_controller mbox;
> > > > + const struct mtk_vcp_mbox_cfg *cfg;
> > > > + struct mtk_ipi_info ipi_recv;
> > >
> > > Maybe also have "struct mbox_chan chan[1]; " so that you don't
> > > have
> > > to
> > > allocate one during the probe.
> > > Also if you have "struct mbox_controller mbox;" as the first
> > > member,
> > > you could simply typecast that to get this structure.
> > > Something like "struct mpfs_mbox" in mailbox-mpfs.c
> > >
> >
> >
> > ERROR:FLEXIBLE_ARRAY: Use C99 flexible arrays - see
> >
https://urldefense.com/v3/__https://docs.kernel.org/process/deprecated.html*zero-length-and-one-element-arrays__;Iw!!CTRNKA9wMg0ARbw!kLlX71HetZwXMZ9UmdtvMEKKykbZINIUNVW5nLVfoztdkSJMlaa3QfbzZxGKIkSgqmHHc2Lvfwpj4URsOVCtekNCFh5L$
> > #81: FILE: drivers/mailbox/mtk-vcp-mailbox.c:24:
> > + struct mbox_chan chans[1];
> > +};
> >
> > Can we ignore this error?
> >
>
> It seems single element style is deprecated. While we know what we
> are
> doing, let us placate that error by
> struct mbox_chan mch;
> struct mbox_chan chans[];
> and set chans = &mch
Do you have any specific considerations for suggesting this approach?
Wo
uld it be sufficient to just define a 'struct mbox_chan chans'?
On Thu, 2025-09-18 at 18:50 -0500, Jassi Brar wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
>
>
> On Thu, Aug 21, 2025 at 9:12 PM Jjian Zhou <jjian.zhou@mediatek.com>
> wrote:
>
> .....
>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/slab.h>
> > +
> > +struct mtk_vcp_mbox_priv {
>
> Maybe 'mtk_vcp_mbox' is a more appropriate name ?
>
> > + void __iomem *base;
> > + struct device *dev;
> > + struct mbox_controller mbox;
> > + const struct mtk_vcp_mbox_cfg *cfg;
> > + struct mtk_ipi_info ipi_recv;
>
> Maybe also have "struct mbox_chan chan[1]; " so that you don't have
> to
> allocate one during the probe.
> Also if you have "struct mbox_controller mbox;" as the first member,
> you could simply typecast that to get this structure.
> Something like "struct mpfs_mbox" in mailbox-mpfs.c
>
The define "struct mbox_chan chan[1]" has style error.
ERROR:FLEXIBLE_ARRAY: Use C99 flexible arrays - see
https://docs.kernel.org/process/deprecated.html#zero-length-and-one-element-arrays
#81: FILE: drivers/mailbox/mtk-vcp-mailbox.c:24:
+ struct mbox_chan chans[0];
+};
How about this error?
> ....
> > +
> > +static struct mbox_chan *mtk_vcp_mbox_xlate(struct mbox_controller
> > *mbox,
> > + const struct
> > of_phandle_args *sp)
> > +{
> > + if (sp->args_count)
> > + return NULL;
> > +
> > + return mbox->chans;
>
> return &mbox->chans[0] seems better.
>
> thnx
On Thu, 2025-09-18 at 18:50 -0500, Jassi Brar wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
>
>
> On Thu, Aug 21, 2025 at 9:12 PM Jjian Zhou <jjian.zhou@mediatek.com>
> wrote:
>
> .....
>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/slab.h>
> > +
> > +struct mtk_vcp_mbox_priv {
>
> Maybe 'mtk_vcp_mbox' is a more appropriate name ?
OK, I replace mtk_vcp_mbox_priv with mtk_vcp_mbox in the next version.
>
> > + void __iomem *base;
> > + struct device *dev;
> > + struct mbox_controller mbox;
> > + const struct mtk_vcp_mbox_cfg *cfg;
> > + struct mtk_ipi_info ipi_recv;
>
> Maybe also have "struct mbox_chan chan[1]; " so that you don't have
> to
> allocate one during the probe.
> Also if you have "struct mbox_controller mbox;" as the first member,
> you could simply typecast that to get this structure.
> Something like "struct mpfs_mbox" in mailbox-mpfs.c
>
> ....
> > +
> > +static struct mbox_chan *mtk_vcp_mbox_xlate(struct mbox_controller
> > *mbox,
> > + const struct
> > of_phandle_args *sp)
> > +{
> > + if (sp->args_count)
> > + return NULL;
> > +
> > + return mbox->chans;
>
> return &mbox->chans[0] seems better.
OK.
>
> thnx
On Fri, Sep 19, 2025 at 7:50 AM Jassi Brar <jassisinghbrar@gmail.com> wrote:
>
> On Thu, Aug 21, 2025 at 9:12 PM Jjian Zhou <jjian.zhou@mediatek.com> wrote:
>
> .....
>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/slab.h>
> > +
> > +struct mtk_vcp_mbox_priv {
> Maybe 'mtk_vcp_mbox' is a more appropriate name ?
>
> > + void __iomem *base;
> > + struct device *dev;
> > + struct mbox_controller mbox;
> > + const struct mtk_vcp_mbox_cfg *cfg;
> > + struct mtk_ipi_info ipi_recv;
>
> Maybe also have "struct mbox_chan chan[1]; " so that you don't have to
> allocate one during the probe.
> Also if you have "struct mbox_controller mbox;" as the first member,
> you could simply typecast that to get this structure.
> Something like "struct mpfs_mbox" in mailbox-mpfs.c
I read somewhere that this way of subclassing is not recommended.
Instead the base class should explicitly not be the first member.
And then container_of() should be used.
I don't remember where I read this though. But I think the explicit
container_of() is easier for understanding the intent.
ChenYu
> ....
> > +
> > +static struct mbox_chan *mtk_vcp_mbox_xlate(struct mbox_controller *mbox,
> > + const struct of_phandle_args *sp)
> > +{
> > + if (sp->args_count)
> > + return NULL;
> > +
> > + return mbox->chans;
>
> return &mbox->chans[0] seems better.
>
> thnx
On Fri, Sep 19, 2025 at 3:31 AM Chen-Yu Tsai <wenst@chromium.org> wrote:
>
> On Fri, Sep 19, 2025 at 7:50 AM Jassi Brar <jassisinghbrar@gmail.com> wrote:
> >
> > On Thu, Aug 21, 2025 at 9:12 PM Jjian Zhou <jjian.zhou@mediatek.com> wrote:
> >
> > .....
> >
> > > +#include <linux/module.h>
> > > +#include <linux/of.h>
> > > +#include <linux/platform_device.h>
> > > +#include <linux/slab.h>
> > > +
> > > +struct mtk_vcp_mbox_priv {
> > Maybe 'mtk_vcp_mbox' is a more appropriate name ?
> >
> > > + void __iomem *base;
> > > + struct device *dev;
> > > + struct mbox_controller mbox;
> > > + const struct mtk_vcp_mbox_cfg *cfg;
> > > + struct mtk_ipi_info ipi_recv;
> >
> > Maybe also have "struct mbox_chan chan[1]; " so that you don't have to
> > allocate one during the probe.
>
> > Also if you have "struct mbox_controller mbox;" as the first member,
> > you could simply typecast that to get this structure.
> > Something like "struct mpfs_mbox" in mailbox-mpfs.c
>
> I read somewhere that this way of subclassing is not recommended.
> Instead the base class should explicitly not be the first member.
> And then container_of() should be used.
>
> I don't remember where I read this though. But I think the explicit
> container_of() is easier for understanding the intent.
>
And how does container_of() work ? :)
typcasting the first member to its parent is the simplest form of container_of.
-j
On Fri, Aug 22, 2025 at 10:12 AM Jjian Zhou <jjian.zhou@mediatek.com> wrote:
>
> Add mtk-vcp-mailbox driver to support the communication with
> VCP remote microprocessor.
>
> Signed-off-by: Jjian Zhou <jjian.zhou@mediatek.com>
Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
A couple minor comments below.
> ---
> drivers/mailbox/Kconfig | 9 ++
> drivers/mailbox/Makefile | 2 +
> drivers/mailbox/mtk-vcp-mailbox.c | 174 ++++++++++++++++++++++++
> include/linux/mailbox/mtk-vcp-mailbox.h | 32 +++++
> 4 files changed, 217 insertions(+)
> create mode 100644 drivers/mailbox/mtk-vcp-mailbox.c
> create mode 100644 include/linux/mailbox/mtk-vcp-mailbox.h
>
> diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
> index 02432d4a5ccd..c28bdb855663 100644
> --- a/drivers/mailbox/Kconfig
> +++ b/drivers/mailbox/Kconfig
> @@ -294,6 +294,15 @@ config MTK_CMDQ_MBOX
> critical time limitation, such as updating display configuration
> during the vblank.
>
> +config MTK_VCP_MBOX
> + tristate "MediaTek VCP Mailbox Support"
> + depends on ARCH_MEDIATEK || COMPILE_TEST
> + help
> + Say yes here to add support for the MediaTek VCP mailbox driver.
> + The mailbox implementation provides access from the application
> + processor to Video Companion Processor Unit.
> + If unsure say N.
> +
> 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 98a68f838486..07278871d254 100644
> --- a/drivers/mailbox/Makefile
> +++ b/drivers/mailbox/Makefile
> @@ -63,6 +63,8 @@ obj-$(CONFIG_MTK_ADSP_MBOX) += mtk-adsp-mailbox.o
>
> obj-$(CONFIG_MTK_CMDQ_MBOX) += mtk-cmdq-mailbox.o
>
> +obj-$(CONFIG_MTK_VCP_MBOX) += mtk-vcp-mailbox.o
> +
> obj-$(CONFIG_ZYNQMP_IPI_MBOX) += zynqmp-ipi-mailbox.o
>
> obj-$(CONFIG_SUN6I_MSGBOX) += sun6i-msgbox.o
> diff --git a/drivers/mailbox/mtk-vcp-mailbox.c b/drivers/mailbox/mtk-vcp-mailbox.c
> new file mode 100644
> index 000000000000..6f48215896d2
> --- /dev/null
> +++ b/drivers/mailbox/mtk-vcp-mailbox.c
> @@ -0,0 +1,174 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2025 MediaTek Corporation. All rights reserved.
> + * Author: Jjian Zhou <jjian.zhou.@mediatek.com>
> + */
> +
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/mailbox_controller.h>
> +#include <linux/mailbox/mtk-vcp-mailbox.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +struct mtk_vcp_mbox_priv {
> + void __iomem *base;
> + struct device *dev;
> + struct mbox_controller mbox;
> + const struct mtk_vcp_mbox_cfg *cfg;
> + struct mtk_ipi_info ipi_recv;
> +};
> +
> +struct mtk_vcp_mbox_cfg {
> + u32 set_in;
> + u32 clr_out;
> +};
> +
> +static inline struct mtk_vcp_mbox_priv *get_mtk_vcp_mbox_priv(struct mbox_controller *mbox)
> +{
> + return container_of(mbox, struct mtk_vcp_mbox_priv, mbox);
> +}
> +
> +static irqreturn_t mtk_vcp_mbox_irq_thread(int irq, void *data)
> +{
> + struct mbox_chan *chan = data;
> + struct mtk_vcp_mbox_priv *priv = get_mtk_vcp_mbox_priv(chan->mbox);
Since there's only one mailbox, you can just pass the private data,
instead of passing the mbox_chan.
> +
> + /* get irq status */
> + priv->ipi_recv.irq_status = readl(priv->base + priv->cfg->clr_out);
> +
> + __ioread32_copy(priv->ipi_recv.msg, priv->base, MBOX_SLOT_MAX_SIZE / 4);
> +
> + mbox_chan_received_data(chan, &priv->ipi_recv);
> +
> + /* clear irq status */
> + writel(priv->ipi_recv.irq_status, priv->base + priv->cfg->clr_out);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static struct mbox_chan *mtk_vcp_mbox_xlate(struct mbox_controller *mbox,
> + const struct of_phandle_args *sp)
> +{
> + if (sp->args_count)
> + return NULL;
> +
> + return mbox->chans;
> +}
> +
> +static int mtk_vcp_mbox_send_data(struct mbox_chan *chan, void *data)
> +{
> + struct mtk_vcp_mbox_priv *priv = get_mtk_vcp_mbox_priv(chan->mbox);
> + struct mtk_ipi_info *ipi_info = data;
> + u32 status;
> +
> + if (!ipi_info->msg) {
> + dev_err(priv->dev, "msg buffer is NULL.\n");
> + return -EINVAL;
> + }
> +
> + status = readl(priv->base + priv->cfg->set_in) & BIT(ipi_info->index);
> + if (status) {
> + dev_warn(priv->dev, "mailbox IPI %d is busy.\n", ipi_info->id);
> + return -EBUSY;
> + }
> +
> + if (ipi_info->slot_ofs + ipi_info->len > MBOX_SLOT_MAX_SIZE)
> + return -EINVAL;
> + __iowrite32_copy(priv->base + ipi_info->slot_ofs, ipi_info->msg,
> + ipi_info->len);
> +
> + writel(BIT(ipi_info->index), priv->base + priv->cfg->set_in);
> +
> + return 0;
> +}
> +
> +static bool mtk_vcp_mbox_last_tx_done(struct mbox_chan *chan)
> +{
> + struct mtk_ipi_info *ipi_info = chan->active_req;
> + struct mtk_vcp_mbox_priv *priv = get_mtk_vcp_mbox_priv(chan->mbox);
> +
> + return !(readl(priv->base + priv->cfg->set_in) & BIT(ipi_info->index));
> +}
> +
> +static const struct mbox_chan_ops mtk_vcp_mbox_chan_ops = {
> + .send_data = mtk_vcp_mbox_send_data,
> + .last_tx_done = mtk_vcp_mbox_last_tx_done,
> +};
> +
> +static int mtk_vcp_mbox_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct mtk_vcp_mbox_priv *priv;
> + struct mbox_controller *mbox;
> + int ret, irq;
> +
> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->dev = dev;
> + mbox = &priv->mbox;
> + mbox->dev = dev;
> + mbox->ops = &mtk_vcp_mbox_chan_ops;
> + mbox->txdone_irq = false;
> + mbox->txdone_poll = true;
> + mbox->of_xlate = mtk_vcp_mbox_xlate;
> + mbox->num_chans = 1;
> + mbox->chans = devm_kzalloc(dev, sizeof(*mbox->chans), GFP_KERNEL);
> + if (!mbox->chans)
> + return -ENOMEM;
> +
> + priv->ipi_recv.msg = devm_kzalloc(dev, MBOX_SLOT_MAX_SIZE, GFP_KERNEL);
> + if (!priv->ipi_recv.msg)
> + return -ENOMEM;
> +
> + priv->base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(priv->base))
> + return PTR_ERR(priv->base);
> +
> + priv->cfg = of_device_get_match_data(dev);
> + if (!priv->cfg)
> + return -EINVAL;
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0)
> + return irq;
> +
> + ret = devm_request_threaded_irq(dev, irq, NULL,
> + mtk_vcp_mbox_irq_thread, IRQF_ONESHOT,
> + dev_name(dev), mbox->chans);
> + if (ret < 0)
> + return ret;
> +
> + platform_set_drvdata(pdev, priv);
> +
> + return devm_mbox_controller_register(dev, &priv->mbox);
> +}
> +
> +static const struct mtk_vcp_mbox_cfg mt8196_cfg = {
> + .set_in = 0x100,
> + .clr_out = 0x10C,
^ use lowercase for hex numbers.
> +};
> +
> +static const struct of_device_id mtk_vcp_mbox_of_match[] = {
> + { .compatible = "mediatek,mt8196-vcp-mbox", .data = &mt8196_cfg },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, mtk_vcp_mbox_of_match);
> +
> +static struct platform_driver mtk_vcp_mbox_driver = {
> + .probe = mtk_vcp_mbox_probe,
> + .driver = {
> + .name = "mtk_vcp_mbox",
> + .of_match_table = mtk_vcp_mbox_of_match,
> + },
> +};
> +module_platform_driver(mtk_vcp_mbox_driver);
> +
> +MODULE_AUTHOR("Jjian Zhou <jjian.zhou@mediatek.com>");
> +MODULE_DESCRIPTION("MTK VCP Mailbox Controller");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/mailbox/mtk-vcp-mailbox.h b/include/linux/mailbox/mtk-vcp-mailbox.h
> new file mode 100644
> index 000000000000..143fb0d06e30
> --- /dev/null
> +++ b/include/linux/mailbox/mtk-vcp-mailbox.h
> @@ -0,0 +1,32 @@
> +/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
> +/*
> + * Copyright (c) 2025 MediaTek Inc.
> + */
> +
> +#ifndef __MTK_VCP_MAILBOX_H__
> +#define __MTK_VCP_MAILBOX_H__
> +
> +#define MBOX_SLOT_MAX_SIZE 0x100 /* mbox max slot size */
> +
> +/**
> + * struct mtk_ipi_info - mailbox message info for mtk-vcp-mailbox
> + * @msg: The share buffer between IPC and mailbox driver
> + * @len: Message length
> + * @id: This is for identification purposes and not actually used
> + * by the mailbox hardware.
> + * @index: The signal number of the mailbox message.
> + * @slot_ofs: Data slot offset.
> + * @irq_status: Captures incoming signals for the RX path.
> + *
> + * It is used between IPC with mailbox driver.
> + */
> +struct mtk_ipi_info {
> + void *msg;
> + u32 len;
> + u32 id;
> + u32 index;
> + u32 slot_ofs;
> + u32 irq_status;
> +};
> +
> +#endif
> --
> 2.46.0
>
On Fri, 2025-08-22 at 13:48 +0800, Chen-Yu Tsai wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
>
>
> On Fri, Aug 22, 2025 at 10:12 AM Jjian Zhou <jjian.zhou@mediatek.com>
> wrote:
> >
> > Add mtk-vcp-mailbox driver to support the communication with
> > VCP remote microprocessor.
> >
> > Signed-off-by: Jjian Zhou <jjian.zhou@mediatek.com>
>
> Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
>
> A couple minor comments below.
>
> > ---
> > drivers/mailbox/Kconfig | 9 ++
> > drivers/mailbox/Makefile | 2 +
> > drivers/mailbox/mtk-vcp-mailbox.c | 174
> > ++++++++++++++++++++++++
> > include/linux/mailbox/mtk-vcp-mailbox.h | 32 +++++
> > 4 files changed, 217 insertions(+)
> > create mode 100644 drivers/mailbox/mtk-vcp-mailbox.c
> > create mode 100644 include/linux/mailbox/mtk-vcp-mailbox.h
> >
> > diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
> > index 02432d4a5ccd..c28bdb855663 100644
> > --- a/drivers/mailbox/Kconfig
> > +++ b/drivers/mailbox/Kconfig
> > @@ -294,6 +294,15 @@ config MTK_CMDQ_MBOX
> > critical time limitation, such as updating display
> > configuration
> > during the vblank.
> >
> > +config MTK_VCP_MBOX
> > + tristate "MediaTek VCP Mailbox Support"
> > + depends on ARCH_MEDIATEK || COMPILE_TEST
> > + help
> > + Say yes here to add support for the MediaTek VCP mailbox
> > driver.
> > + The mailbox implementation provides access from the
> > application
> > + processor to Video Companion Processor Unit.
> > + If unsure say N.
> > +
> > 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 98a68f838486..07278871d254 100644
> > --- a/drivers/mailbox/Makefile
> > +++ b/drivers/mailbox/Makefile
> > @@ -63,6 +63,8 @@ obj-$(CONFIG_MTK_ADSP_MBOX) += mtk-adsp-
> > mailbox.o
> >
> > obj-$(CONFIG_MTK_CMDQ_MBOX) += mtk-cmdq-mailbox.o
> >
> > +obj-$(CONFIG_MTK_VCP_MBOX) += mtk-vcp-mailbox.o
> > +
> > obj-$(CONFIG_ZYNQMP_IPI_MBOX) += zynqmp-ipi-mailbox.o
> >
> > obj-$(CONFIG_SUN6I_MSGBOX) += sun6i-msgbox.o
> > diff --git a/drivers/mailbox/mtk-vcp-mailbox.c
> > b/drivers/mailbox/mtk-vcp-mailbox.c
> > new file mode 100644
> > index 000000000000..6f48215896d2
> > --- /dev/null
> > +++ b/drivers/mailbox/mtk-vcp-mailbox.c
> > @@ -0,0 +1,174 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (c) 2025 MediaTek Corporation. All rights reserved.
> > + * Author: Jjian Zhou <jjian.zhou.@mediatek.com>
> > + */
> > +
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/kernel.h>
> > +#include <linux/mailbox_controller.h>
> > +#include <linux/mailbox/mtk-vcp-mailbox.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/slab.h>
> > +
> > +struct mtk_vcp_mbox_priv {
> > + void __iomem *base;
> > + struct device *dev;
> > + struct mbox_controller mbox;
> > + const struct mtk_vcp_mbox_cfg *cfg;
> > + struct mtk_ipi_info ipi_recv;
> > +};
> > +
> > +struct mtk_vcp_mbox_cfg {
> > + u32 set_in;
> > + u32 clr_out;
> > +};
> > +
> > +static inline struct mtk_vcp_mbox_priv
> > *get_mtk_vcp_mbox_priv(struct mbox_controller *mbox)
> > +{
> > + return container_of(mbox, struct mtk_vcp_mbox_priv, mbox);
> > +}
> > +
> > +static irqreturn_t mtk_vcp_mbox_irq_thread(int irq, void *data)
> > +{
> > + struct mbox_chan *chan = data;
> > + struct mtk_vcp_mbox_priv *priv =
> > get_mtk_vcp_mbox_priv(chan->mbox);
>
> Since there's only one mailbox, you can just pass the private data,
> instead of passing the mbox_chan.
I got it. Modification like below:
struct mtk_vcp_mbox_priv *priv = data;
ret = devm_request_threaded_irq(dev, irq, NULL,
mtk_vcp_mbox_irq_thread, IRQF_ONESHOT,
dev_name(dev), priv);
>
> > +
> > + /* get irq status */
> > + priv->ipi_recv.irq_status = readl(priv->base + priv->cfg-
> > >clr_out);
> > +
> > + __ioread32_copy(priv->ipi_recv.msg, priv->base,
> > MBOX_SLOT_MAX_SIZE / 4);
> > +
> > + mbox_chan_received_data(chan, &priv->ipi_recv);
> > +
> > + /* clear irq status */
> > + writel(priv->ipi_recv.irq_status, priv->base + priv->cfg-
> > >clr_out);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static struct mbox_chan *mtk_vcp_mbox_xlate(struct mbox_controller
> > *mbox,
> > + const struct
> > of_phandle_args *sp)
> > +{
> > + if (sp->args_count)
> > + return NULL;
> > +
> > + return mbox->chans;
> > +}
> > +
> > +static int mtk_vcp_mbox_send_data(struct mbox_chan *chan, void
> > *data)
> > +{
> > + struct mtk_vcp_mbox_priv *priv =
> > get_mtk_vcp_mbox_priv(chan->mbox);
> > + struct mtk_ipi_info *ipi_info = data;
> > + u32 status;
> > +
> > + if (!ipi_info->msg) {
> > + dev_err(priv->dev, "msg buffer is NULL.\n");
> > + return -EINVAL;
> > + }
> > +
> > + status = readl(priv->base + priv->cfg->set_in) &
> > BIT(ipi_info->index);
> > + if (status) {
> > + dev_warn(priv->dev, "mailbox IPI %d is busy.\n",
> > ipi_info->id);
> > + return -EBUSY;
> > + }
> > +
> > + if (ipi_info->slot_ofs + ipi_info->len >
> > MBOX_SLOT_MAX_SIZE)
> > + return -EINVAL;
> > + __iowrite32_copy(priv->base + ipi_info->slot_ofs, ipi_info-
> > >msg,
> > + ipi_info->len);
> > +
> > + writel(BIT(ipi_info->index), priv->base + priv->cfg-
> > >set_in);
> > +
> > + return 0;
> > +}
> > +
> > +static bool mtk_vcp_mbox_last_tx_done(struct mbox_chan *chan)
> > +{
> > + struct mtk_ipi_info *ipi_info = chan->active_req;
> > + struct mtk_vcp_mbox_priv *priv =
> > get_mtk_vcp_mbox_priv(chan->mbox);
> > +
> > + return !(readl(priv->base + priv->cfg->set_in) &
> > BIT(ipi_info->index));
> > +}
> > +
> > +static const struct mbox_chan_ops mtk_vcp_mbox_chan_ops = {
> > + .send_data = mtk_vcp_mbox_send_data,
> > + .last_tx_done = mtk_vcp_mbox_last_tx_done,
> > +};
> > +
> > +static int mtk_vcp_mbox_probe(struct platform_device *pdev)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct mtk_vcp_mbox_priv *priv;
> > + struct mbox_controller *mbox;
> > + int ret, irq;
> > +
> > + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> > + if (!priv)
> > + return -ENOMEM;
> > +
> > + priv->dev = dev;
> > + mbox = &priv->mbox;
> > + mbox->dev = dev;
> > + mbox->ops = &mtk_vcp_mbox_chan_ops;
> > + mbox->txdone_irq = false;
> > + mbox->txdone_poll = true;
> > + mbox->of_xlate = mtk_vcp_mbox_xlate;
> > + mbox->num_chans = 1;
> > + mbox->chans = devm_kzalloc(dev, sizeof(*mbox->chans),
> > GFP_KERNEL);
> > + if (!mbox->chans)
> > + return -ENOMEM;
> > +
> > + priv->ipi_recv.msg = devm_kzalloc(dev, MBOX_SLOT_MAX_SIZE,
> > GFP_KERNEL);
> > + if (!priv->ipi_recv.msg)
> > + return -ENOMEM;
> > +
> > + priv->base = devm_platform_ioremap_resource(pdev, 0);
> > + if (IS_ERR(priv->base))
> > + return PTR_ERR(priv->base);
> > +
> > + priv->cfg = of_device_get_match_data(dev);
> > + if (!priv->cfg)
> > + return -EINVAL;
> > +
> > + irq = platform_get_irq(pdev, 0);
> > + if (irq < 0)
> > + return irq;
> > +
> > + ret = devm_request_threaded_irq(dev, irq, NULL,
> > + mtk_vcp_mbox_irq_thread,
> > IRQF_ONESHOT,
> > + dev_name(dev), mbox-
> > >chans);
> > + if (ret < 0)
> > + return ret;
> > +
> > + platform_set_drvdata(pdev, priv);
> > +
> > + return devm_mbox_controller_register(dev, &priv->mbox);
> > +}
> > +
> > +static const struct mtk_vcp_mbox_cfg mt8196_cfg = {
> > + .set_in = 0x100,
> > + .clr_out = 0x10C,
>
> ^ use lowercase for hex numbers.
Thanks.
>
> > +};
> > +
> > +static const struct of_device_id mtk_vcp_mbox_of_match[] = {
> > + { .compatible = "mediatek,mt8196-vcp-mbox", .data =
> > &mt8196_cfg },
> > + {},
> > +};
> > +MODULE_DEVICE_TABLE(of, mtk_vcp_mbox_of_match);
> > +
> > +static struct platform_driver mtk_vcp_mbox_driver = {
> > + .probe = mtk_vcp_mbox_probe,
> > + .driver = {
> > + .name = "mtk_vcp_mbox",
> > + .of_match_table = mtk_vcp_mbox_of_match,
> > + },
> > +};
> > +module_platform_driver(mtk_vcp_mbox_driver);
> > +
> > +MODULE_AUTHOR("Jjian Zhou <jjian.zhou@mediatek.com>");
> > +MODULE_DESCRIPTION("MTK VCP Mailbox Controller");
> > +MODULE_LICENSE("GPL");
> > diff --git a/include/linux/mailbox/mtk-vcp-mailbox.h
> > b/include/linux/mailbox/mtk-vcp-mailbox.h
> > new file mode 100644
> > index 000000000000..143fb0d06e30
> > --- /dev/null
> > +++ b/include/linux/mailbox/mtk-vcp-mailbox.h
> > @@ -0,0 +1,32 @@
> > +/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
> > +/*
> > + * Copyright (c) 2025 MediaTek Inc.
> > + */
> > +
> > +#ifndef __MTK_VCP_MAILBOX_H__
> > +#define __MTK_VCP_MAILBOX_H__
> > +
> > +#define MBOX_SLOT_MAX_SIZE 0x100 /* mbox max slot size */
> > +
> > +/**
> > + * struct mtk_ipi_info - mailbox message info for mtk-vcp-mailbox
> > + * @msg: The share buffer between IPC and mailbox driver
> > + * @len: Message length
> > + * @id: This is for identification purposes and not actually used
> > + * by the mailbox hardware.
> > + * @index: The signal number of the mailbox message.
> > + * @slot_ofs: Data slot offset.
> > + * @irq_status: Captures incoming signals for the RX path.
> > + *
> > + * It is used between IPC with mailbox driver.
> > + */
> > +struct mtk_ipi_info {
> > + void *msg;
> > + u32 len;
> > + u32 id;
> > + u32 index;
> > + u32 slot_ofs;
> > + u32 irq_status;
> > +};
> > +
> > +#endif
> > --
> > 2.46.0
> >
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