mailbox: mediatek: add support for adsp mailbox controller

This patch is to for MediaTek ADSP IPC mailbox controller driver
It is used to send short messages between processors with adsp

Signed-off-by: Allen-KH Cheng <[e-mail]>
Reviewed-by: Tzung-Bi Shih <[e-mail]>
Reviewed-by: YC Hung <[e-mail]>
Reviewed-by: AngeloGioacchino Del Regno <[e-mail]>
Signed-off-by: Jassi Brar <[e-mail]>

drivers/mailbox/Kconfig

···
 	  with hardware for Inter-Processor Communication Controller (IPCC)
 	  between processors. Say Y here if you want to have this support.
 
+config MTK_ADSP_MBOX
+	tristate "MediaTek ADSP Mailbox Controller"
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+	help
+          Say yes here to add support for "MediaTek ADSP Mailbox Controller.
+          This mailbox driver is used to send notification or short message
+          between processors with ADSP. It will place the message to share
+	  buffer and will access the ipc control.
+
 config MTK_CMDQ_MBOX
 	tristate "MediaTek CMDQ Mailbox Support"
 	depends on ARCH_MEDIATEK || COMPILE_TEST

drivers/mailbox/Makefile

···
 
 obj-$(CONFIG_STM32_IPCC) 	+= stm32-ipcc.o
 
+obj-$(CONFIG_MTK_ADSP_MBOX)	+= mtk-adsp-mailbox.o
+
 obj-$(CONFIG_MTK_CMDQ_MBOX)	+= mtk-cmdq-mailbox.o
 
 obj-$(CONFIG_ZYNQMP_IPI_MBOX)	+= zynqmp-ipi-mailbox.o

drivers/mailbox/mtk-adsp-mailbox.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022 MediaTek Corporation. All rights reserved.
+ * Author: Allen-KH Cheng <[e-mail]>
+ */
+
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_controller.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/slab.h>
+
+struct mtk_adsp_mbox_priv {
+	struct device *dev;
+	struct mbox_controller mbox;
+	void __iomem *va_mboxreg;
+	const struct mtk_adsp_mbox_cfg *cfg;
+};
+
+struct mtk_adsp_mbox_cfg {
+	u32 set_in;
+	u32 set_out;
+	u32 clr_in;
+	u32 clr_out;
+};
+
+static inline struct mtk_adsp_mbox_priv *get_mtk_adsp_mbox_priv(struct mbox_controller *mbox)
+{
+	return container_of(mbox, struct mtk_adsp_mbox_priv, mbox);
+}
+
+static irqreturn_t mtk_adsp_mbox_irq(int irq, void *data)
+{
+	struct mbox_chan *chan = data;
+	struct mtk_adsp_mbox_priv *priv = get_mtk_adsp_mbox_priv(chan->mbox);
+	u32 op = readl(priv->va_mboxreg + priv->cfg->set_out);
+
+	writel(op, priv->va_mboxreg + priv->cfg->clr_out);
+
+	return IRQ_WAKE_THREAD;
+}
+
+static irqreturn_t mtk_adsp_mbox_isr(int irq, void *data)
+{
+	struct mbox_chan *chan = data;
+
+	mbox_chan_received_data(chan, NULL);
+
+	return IRQ_HANDLED;
+}
+
+static struct mbox_chan *mtk_adsp_mbox_xlate(struct mbox_controller *mbox,
+					     const struct of_phandle_args *sp)
+{
+	return mbox->chans;
+}
+
+static int mtk_adsp_mbox_startup(struct mbox_chan *chan)
+{
+	struct mtk_adsp_mbox_priv *priv = get_mtk_adsp_mbox_priv(chan->mbox);
+
+	/* Clear ADSP mbox command */
+	writel(0xFFFFFFFF, priv->va_mboxreg + priv->cfg->clr_in);
+	writel(0xFFFFFFFF, priv->va_mboxreg + priv->cfg->clr_out);
+
+	return 0;
+}
+
+static void mtk_adsp_mbox_shutdown(struct mbox_chan *chan)
+{
+	struct mtk_adsp_mbox_priv *priv = get_mtk_adsp_mbox_priv(chan->mbox);
+
+	/* Clear ADSP mbox command */
+	writel(0xFFFFFFFF, priv->va_mboxreg + priv->cfg->clr_in);
+	writel(0xFFFFFFFF, priv->va_mboxreg + priv->cfg->clr_out);
+}
+
+static int mtk_adsp_mbox_send_data(struct mbox_chan *chan, void *data)
+{
+	struct mtk_adsp_mbox_priv *priv = get_mtk_adsp_mbox_priv(chan->mbox);
+	u32 *msg = data;
+
+	writel(*msg, priv->va_mboxreg + priv->cfg->set_in);
+
+	return 0;
+}
+
+static bool mtk_adsp_mbox_last_tx_done(struct mbox_chan *chan)
+{
+	struct mtk_adsp_mbox_priv *priv = get_mtk_adsp_mbox_priv(chan->mbox);
+
+	return readl(priv->va_mboxreg + priv->cfg->set_in) == 0;
+}
+
+static const struct mbox_chan_ops mtk_adsp_mbox_chan_ops = {
+	.send_data	= mtk_adsp_mbox_send_data,
+	.startup	= mtk_adsp_mbox_startup,
+	.shutdown	= mtk_adsp_mbox_shutdown,
+	.last_tx_done	= mtk_adsp_mbox_last_tx_done,
+};
+
+static int mtk_adsp_mbox_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mtk_adsp_mbox_priv *priv;
+	const struct mtk_adsp_mbox_cfg *cfg;
+	struct mbox_controller *mbox;
+	int ret, irq;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	mbox = &priv->mbox;
+	mbox->dev = dev;
+	mbox->ops = &mtk_adsp_mbox_chan_ops;
+	mbox->txdone_irq = false;
+	mbox->txdone_poll = true;
+	mbox->of_xlate = mtk_adsp_mbox_xlate;
+	mbox->num_chans = 1;
+	mbox->chans = devm_kzalloc(dev, sizeof(*mbox->chans), GFP_KERNEL);
+	if (!mbox->chans)
+		return -ENOMEM;
+
+	priv->va_mboxreg = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(priv->va_mboxreg))
+		return PTR_ERR(priv->va_mboxreg);
+
+	cfg = of_device_get_match_data(dev);
+	if (!cfg)
+		return -EINVAL;
+	priv->cfg = cfg;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	ret = devm_request_threaded_irq(dev, irq, mtk_adsp_mbox_irq,
+					mtk_adsp_mbox_isr, IRQF_TRIGGER_NONE,
+					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_adsp_mbox_cfg mt8195_adsp_mbox_cfg = {
+	.set_in		= 0x00,
+	.set_out	= 0x1c,
+	.clr_in		= 0x04,
+	.clr_out	= 0x20,
+};
+
+static const struct of_device_id mtk_adsp_mbox_of_match[] = {
+	{ .compatible = "mediatek,mt8195-adsp-mbox", .data = &mt8195_adsp_mbox_cfg },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mtk_adsp_mbox_of_match);
+
+static struct platform_driver mtk_adsp_mbox_driver = {
+	.probe		= mtk_adsp_mbox_probe,
+	.driver = {
+		.name	= "mtk_adsp_mbox",
+		.of_match_table = mtk_adsp_mbox_of_match,
+	},
+};
+module_platform_driver(mtk_adsp_mbox_driver);
+
+MODULE_AUTHOR("Allen-KH Cheng <[e-mail]>");
+MODULE_DESCRIPTION("MTK ADSP Mailbox Controller");
+MODULE_LICENSE("GPL v2");