[PATCH] firmware: mediatek: add adsp ipc protocol interface

[Allen-KH Cheng]

Some of mediatek processors contain
the Tensilica HiFix DSP for audio processing.

The communication between Host CPU and DSP firmware is
taking place using a shared memory area for message passing.

ADSP IPC protocol offers (send/recv) interfaces using
mediatek-mailbox APIs.

We use two mbox channels to implement a request-reply protocol.

Signed-off-by: Allen-KH Cheng <Allen-KH.Cheng@xxxxxxxxxxxx>
---
 drivers/firmware/Kconfig                      |   1 +
 drivers/firmware/Makefile                     |   1 +
 drivers/firmware/mediatek/Kconfig             |  10 ++
 drivers/firmware/mediatek/Makefile            |   2 +
 drivers/firmware/mediatek/mtk-adsp-ipc.c      | 130 ++++++++++++++++++
 .../linux/firmware/mediatek/mtk-adsp-ipc.h    |  73 ++++++++++
 6 files changed, 217 insertions(+)
 create mode 100644 drivers/firmware/mediatek/Kconfig
 create mode 100644 drivers/firmware/mediatek/Makefile
 create mode 100644 drivers/firmware/mediatek/mtk-adsp-ipc.c
 create mode 100644 include/linux/firmware/mediatek/mtk-adsp-ipc.h

diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index 220a58cf0a44..005f76a9a31a 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -301,6 +301,7 @@ source "drivers/firmware/broadcom/Kconfig"
 source "drivers/firmware/google/Kconfig"
 source "drivers/firmware/efi/Kconfig"
 source "drivers/firmware/imx/Kconfig"
+source "drivers/firmware/mediatek/Kconfig"
 source "drivers/firmware/meson/Kconfig"
 source "drivers/firmware/psci/Kconfig"
 source "drivers/firmware/smccc/Kconfig"
diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
index 5ced0673d94b..c0d1f3bdeae4 100644
--- a/drivers/firmware/Makefile
+++ b/drivers/firmware/Makefile
@@ -33,6 +33,7 @@ obj-$(CONFIG_GOOGLE_FIRMWARE)	+= google/
 obj-$(CONFIG_EFI)		+= efi/
 obj-$(CONFIG_UEFI_CPER)		+= efi/
 obj-y				+= imx/
+obj-y				+= mediatek/
 obj-y				+= psci/
 obj-y				+= smccc/
 obj-y				+= tegra/
diff --git a/drivers/firmware/mediatek/Kconfig b/drivers/firmware/mediatek/Kconfig
new file mode 100644
index 000000000000..84a3b3bf5146
--- /dev/null
+++ b/drivers/firmware/mediatek/Kconfig
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config MTK_ADSP_IPC
+	tristate "MTK ADSP IPC Protocol driver"
+	depends on MTK_ADSP_IPC_MBOX
+	help
+	  Say yes here to add support for the MediaTek ADSP IPC protocol
+	  between host AP (Linux) and the firmware running on ADSP.
+	  ADSP exists on some mtk processors.
+	  Client might use shared memory to exchange information with ADSP side.
+
diff --git a/drivers/firmware/mediatek/Makefile b/drivers/firmware/mediatek/Makefile
new file mode 100644
index 000000000000..4e840b65650d
--- /dev/null
+++ b/drivers/firmware/mediatek/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_MTK_ADSP_IPC)		+= mtk-adsp-ipc.o
diff --git a/drivers/firmware/mediatek/mtk-adsp-ipc.c b/drivers/firmware/mediatek/mtk-adsp-ipc.c
new file mode 100644
index 000000000000..7307c55b5628
--- /dev/null
+++ b/drivers/firmware/mediatek/mtk-adsp-ipc.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2021 MediaTek Corporation. All rights reserved.
+ * Author: Allen-KH Cheng <allen-kh.cheng@xxxxxxxxxxxx>
+ */
+
+#include <linux/firmware/mediatek/mtk-adsp-ipc.h>
+#include <linux/kernel.h>
+#include <linux/mailbox_client.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+int adsp_ipc_send(struct mtk_adsp_ipc *ipc, unsigned int idx, uint32_t op)
+{
+	struct mtk_adsp_chan *dsp_chan = &ipc->chans[idx];
+	struct adsp_mbox_ch_info *ch_info = dsp_chan->ch->con_priv;
+	int ret;
+
+	if (idx >= MTK_ADSP_MBOX_NUM)
+		return -EINVAL;
+
+	ch_info->ipc_op_val = op;
+	ret = mbox_send_message(dsp_chan->ch, NULL);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+EXPORT_SYMBOL(adsp_ipc_send);
+
+static void adsp_ipc_recv(struct mbox_client *c, void *msg)
+{
+	struct mtk_adsp_chan *chan = container_of(c, struct mtk_adsp_chan, cl);
+
+	if (chan->idx == MTK_ADSP_MBOX_REPLY)
+		chan->ipc->ops->handle_reply(chan->ipc);
+	else
+		chan->ipc->ops->handle_request(chan->ipc);
+}
+
+static int mtk_adsp_ipc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mtk_adsp_ipc *dsp_ipc;
+	struct mtk_adsp_chan *dsp_chan;
+	struct mbox_client *cl;
+	char *chan_name;
+	int ret;
+	int i, j;
+
+	device_set_of_node_from_dev(&pdev->dev, pdev->dev.parent);
+
+	dsp_ipc = devm_kzalloc(dev, sizeof(*dsp_ipc), GFP_KERNEL);
+	if (!dsp_ipc)
+		return -ENOMEM;
+
+	for (i = 0; i < MTK_ADSP_MBOX_NUM; i++) {
+		chan_name = kasprintf(GFP_KERNEL, "mbox%d", i);
+		if (!chan_name)
+			return -ENOMEM;
+
+		dsp_chan = &dsp_ipc->chans[i];
+		cl = &dsp_chan->cl;
+		cl->dev = dev->parent;
+		cl->tx_block = false;
+		cl->knows_txdone = false;
+		cl->tx_prepare = NULL;
+		cl->rx_callback = adsp_ipc_recv;
+
+		dsp_chan->ipc = dsp_ipc;
+		dsp_chan->idx = i;
+		dsp_chan->ch = mbox_request_channel_byname(cl, chan_name);
+		if (IS_ERR(dsp_chan->ch)) {
+			ret = PTR_ERR(dsp_chan->ch);
+			if (ret != -EPROBE_DEFER)
+				dev_err(dev, "Failed to request mbox chan %d ret %d\n",
+					i, ret);
+			goto out;
+		}
+
+		dev_dbg(dev, "request mbox chan %s\n", chan_name);
+		kfree(chan_name);
+	}
+
+	dsp_ipc->dev = dev;
+	dev_set_drvdata(dev, dsp_ipc);
+	dev_dbg(dev, "MTK ADSP IPC initialized\n");
+
+	return 0;
+
+out:
+	kfree(chan_name);
+	for (j = 0; j < i; j++) {
+		dsp_chan = &dsp_ipc->chans[j];
+		mbox_free_channel(dsp_chan->ch);
+	}
+
+	return ret;
+}
+
+static int mtk_adsp_remove(struct platform_device *pdev)
+{
+	struct mtk_adsp_chan *dsp_chan;
+	struct mtk_adsp_ipc *dsp_ipc;
+	int i;
+
+	dsp_ipc = dev_get_drvdata(&pdev->dev);
+
+	for (i = 0; i < MTK_ADSP_MBOX_NUM; i++) {
+		dsp_chan = &dsp_ipc->chans[i];
+		mbox_free_channel(dsp_chan->ch);
+	}
+
+	return 0;
+}
+
+static struct platform_driver mtk_adsp_ipc_driver = {
+	.driver = {
+		.name = "mtk-adsp-ipc",
+	},
+	.probe = mtk_adsp_ipc_probe,
+	.remove = mtk_adsp_remove,
+};
+builtin_platform_driver(mtk_adsp_ipc_driver);
+
+MODULE_AUTHOR("Allen-KH Cheng <allen-kh.cheng@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("MTK ADSP IPC protocol driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/firmware/mediatek/mtk-adsp-ipc.h b/include/linux/firmware/mediatek/mtk-adsp-ipc.h
new file mode 100644
index 000000000000..24361804655f
--- /dev/null
+++ b/include/linux/firmware/mediatek/mtk-adsp-ipc.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2021 MediaTek Inc.
+ */
+
+#ifndef MTK_ADSP_IPC_H
+#define MTK_ADSP_IPC_H
+
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/mailbox_controller.h>
+#include <linux/mailbox_client.h>
+
+#define MTK_ADSP_IPC_REQ 0
+#define MTK_ADSP_IPC_RSP 1
+#define MTK_ADSP_IPC_OP_REQ 0x1
+#define MTK_ADSP_IPC_OP_RSP 0x2
+
+enum {
+	MTK_ADSP_MBOX_REPLY,
+	MTK_ADSP_MBOX_REQUEST,
+	MTK_ADSP_MBOX_NUM,
+};
+
+struct mtk_adsp_ipc;
+
+struct mtk_adsp_ipc_ops {
+	void (*handle_reply)(struct mtk_adsp_ipc *ipc);
+	void (*handle_request)(struct mtk_adsp_ipc *ipc);
+};
+
+struct mtk_adsp_chan {
+	struct mtk_adsp_ipc *ipc;
+	struct mbox_client cl;
+	struct mbox_chan *ch;
+	char *name;
+	int idx;
+};
+
+struct mtk_adsp_ipc {
+	struct mtk_adsp_chan chans[MTK_ADSP_MBOX_NUM];
+	struct device *dev;
+	struct mtk_adsp_ipc_ops *ops;
+	void *private_data;
+};
+
+struct adsp_mbox_ch_info {
+	u32 id;
+	u32 ipc_op_val;
+	void __iomem *va_reg[MTK_ADSP_MBOX_NUM];
+	/* protect access to adsp mbox registers */
+	spinlock_t lock;
+};
+
+static inline void adsp_ipc_set_data(struct mtk_adsp_ipc *ipc, void *data)
+{
+	if (!ipc)
+		return;
+
+	ipc->private_data = data;
+}
+
+static inline void *adsp_ipc_get_data(struct mtk_adsp_ipc *ipc)
+{
+	if (!ipc)
+		return NULL;
+
+	return ipc->private_data;
+}
+
+int adsp_ipc_send(struct mtk_adsp_ipc *ipc, unsigned int idx, uint32_t op);
+
+#endif /* MTK_ADSP_IPC_H */
-- 
2.18.0