Re: [PATCH v6 2/2] mailbox: mediatek: Add mtk-vcp-mailbox driver

[AngeloGioacchino Del Regno]

Il 30/09/25 04:59, Jjian Zhou (周建) ha scritto:
> On Mon, 2025-09-29 at 12:33 +0200, AngeloGioacchino Del Regno wrote:
> > External email : Please do not click links or open attachments until
> > you have verified the sender or the content.
> >
> >
> > Il 26/09/25 11:05, Jjian Zhou ha scritto:
> > > Add mtk-vcp-mailbox driver to support the communication with
> > > VCP remote microprocessor.
> > >
> > > Signed-off-by: Jjian Zhou <jjian.zhou@xxxxxxxxxxxx>
> > > ---
> > >    drivers/mailbox/Kconfig                 |   9 ++
> > >    drivers/mailbox/Makefile                |   2 +
> > >    drivers/mailbox/mtk-vcp-mailbox.c       | 168
> > > ++++++++++++++++++++++++
> > >    include/linux/mailbox/mtk-vcp-mailbox.h |  32 +++++
> > >    4 files changed, 211 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..a2a80d124e50
> > > --- /dev/null
> > > +++ b/drivers/mailbox/mtk-vcp-mailbox.c
> > > @@ -0,0 +1,168 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * Copyright (c) 2025 MediaTek Corporation. All rights reserved.
> > > + * Author: Jjian Zhou <jjian.zhou.@xxxxxxxxxxxx>
> > > + */
> > > +
> > > +#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 {
> > > +     struct mbox_controller mbox;
> > > +     void __iomem *base;
> > > +     struct device *dev;
> > > +     const struct mtk_vcp_mbox_cfg *cfg;
> > > +     struct mtk_ipi_info ipi_recv;
> > > +     struct mbox_chan chans;
> > > +};
> > > +
> > > +struct mtk_vcp_mbox_cfg {
> > > +     u32 set_in;
> > > +     u32 clr_out;
> >
> > u16 is enough for both register offsets, at least for now - and I
> > suspect it's
> > going to be enough forever.
>
> OK. I change u32 to u16 in the next version.
>
> > > +};
> > > +
> > > +static irqreturn_t mtk_vcp_mbox_irq_thread(int irq, void *data)
> > > +{
> > > +     struct mtk_vcp_mbox *priv = data;
> > > +
> > > +     /* 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(&priv->chans, &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[0];
> > > +}
> > > +
> > > +static int mtk_vcp_mbox_send_data(struct mbox_chan *chan, void
> > > *data)
> > > +{
> > > +     struct mtk_vcp_mbox *priv = chan->con_priv;
> > > +     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);
> >
> > status = readl(priv->base + priv->cfg->set_in);
> > if (status & BIT(ipi_info->index) {
> >    ....
> > }
>
> OK.
>
> > > +     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 = chan->con_priv;
> > > +
> > > +     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;
> > > +     struct mbox_controller *mbox;
> > > +     int ret, irq;
> > > +
> > > +     priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> > > +     if (!priv)
> > > +             return -ENOMEM;
> > > +
> > > +     priv->dev = dev;
> > > +     priv->chans.con_priv = priv;
> > > +     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 = &priv->chans;
> > > +
> > > +     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;
> > > +
> >
> > Please set the driver data before requesting the interrupt: what
> > happens if the
> > ISR is run before having driver data available otherwise?! :-)
>
> OK, I put the "platform_set_drvdata(pdev, priv)" between
> "of_device_get_match_data(dev)" and "platform_get_irq(pdev, 0)".
>
> Do you want me to submit a new version right now?

Yes, please.

Cheers,
Angelo