mailbox: mediatek: Add mtk-vcp-mailbox driver

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>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>

diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index 29f16f220384fc23fc735f827415f30f5cedb888..d7f8db25f3b38e272fce13c6bde1e8b1d43cd387 100644 (file)
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -304,6 +304,15 @@ config MTK_GPUEB_MBOX
          Say Y or m here if you want to support the MT8196 SoC in your kernel
          build.
 
+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 81820a4f55285580dcc4acdc713a50d94d6f16c0..944d8ea39f3499aa4b6eaffcacec18b0df6000a2 100644 (file)
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -65,6 +65,8 @@ obj-$(CONFIG_MTK_CMDQ_MBOX)   += mtk-cmdq-mailbox.o
 
 obj-$(CONFIG_MTK_GPUEB_MBOX)   += mtk-gpueb-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 (file)
index 0000000..cedad57
--- /dev/null
+++ b/drivers/mailbox/mtk-vcp-mailbox.c
@@ -0,0 +1,170 @@
+// 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 {
+       u16 set_in;
+       u16 clr_out;
+};
+
+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,
+                       MTK_VCP_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);
+       if (status & BIT(ipi_info->index)) {
+               dev_warn(priv->dev, "mailbox IPI %d is busy.\n", ipi_info->id);
+               return -EBUSY;
+       }
+
+       if (ipi_info->slot_ofs + ipi_info->len > MTK_VCP_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, MTK_VCP_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;
+
+       platform_set_drvdata(pdev, priv);
+
+       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), priv);
+       if (ret < 0)
+               return ret;
+
+       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 (file)
index 0000000..16e59d6
--- /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 MTK_VCP_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