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

[AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>]

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@mediatek.com>
>>> ---
>>>    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.@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 {
>>> +     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