ASoC: imx-audio-rpmsg: Add rpmsg_driver for audio channel

This driver is used to accept the message from rpmsg audio
channel, and if this driver is probed, it will help to register
the platform driver, the platform driver will use this
audio channel to send and receive messages to and from Cortex-M
core.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Link: https://lore.kernel.org/r/1615516725-4975-5-git-send-email-shengjiu.wang@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/fsl/Kconfig

@@ -129,6 +129,10 @@ config SND_SOC_IMX_PCM_DMA
 	tristate
 	select SND_SOC_GENERIC_DMAENGINE_PCM
 
+config SND_SOC_IMX_AUDIO_RPMSG
+	tristate
+	depends on RPMSG
+
 config SND_SOC_IMX_AUDMUX
 	tristate "Digital Audio Mux module support"
 	help

sound/soc/fsl/Makefile

@@ -60,6 +60,7 @@ obj-$(CONFIG_SND_SOC_IMX_AUDMUX) += snd-soc-imx-audmux.o
 
 obj-$(CONFIG_SND_SOC_IMX_PCM_FIQ) += imx-pcm-fiq.o
 obj-$(CONFIG_SND_SOC_IMX_PCM_DMA) += imx-pcm-dma.o
+obj-$(CONFIG_SND_SOC_IMX_AUDIO_RPMSG) += imx-audio-rpmsg.o
 
 # i.MX Machine Support
 snd-soc-eukrea-tlv320-objs := eukrea-tlv320.o

sound/soc/fsl/imx-audio-rpmsg.c

@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright 2017-2020 NXP
+
+#include <linux/module.h>
+#include <linux/rpmsg.h>
+#include "imx-pcm-rpmsg.h"
+
+/*
+ * struct imx_audio_rpmsg: private data
+ *
+ * @rpmsg_pdev: pointer of platform device
+ */
+struct imx_audio_rpmsg {
+	struct platform_device *rpmsg_pdev;
+};
+
+static int imx_audio_rpmsg_cb(struct rpmsg_device *rpdev, void *data, int len,
+			      void *priv, u32 src)
+{
+	struct imx_audio_rpmsg *rpmsg = dev_get_drvdata(&rpdev->dev);
+	struct rpmsg_r_msg *r_msg = (struct rpmsg_r_msg *)data;
+	struct rpmsg_info *info;
+	struct rpmsg_msg *msg;
+	unsigned long flags;
+
+	if (!rpmsg->rpmsg_pdev)
+		return 0;
+
+	info = platform_get_drvdata(rpmsg->rpmsg_pdev);
+
+	dev_dbg(&rpdev->dev, "get from%d: cmd:%d. %d\n",
+		src, r_msg->header.cmd, r_msg->param.resp);
+
+	switch (r_msg->header.type) {
+	case MSG_TYPE_C:
+		/* TYPE C is notification from M core */
+		switch (r_msg->header.cmd) {
+		case TX_PERIOD_DONE:
+			spin_lock_irqsave(&info->lock[TX], flags);
+			msg = &info->msg[TX_PERIOD_DONE + MSG_TYPE_A_NUM];
+			msg->r_msg.param.buffer_tail =
+						r_msg->param.buffer_tail;
+			msg->r_msg.param.buffer_tail %= info->num_period[TX];
+			spin_unlock_irqrestore(&info->lock[TX], flags);
+			info->callback[TX](info->callback_param[TX]);
+			break;
+		case RX_PERIOD_DONE:
+			spin_lock_irqsave(&info->lock[RX], flags);
+			msg = &info->msg[RX_PERIOD_DONE + MSG_TYPE_A_NUM];
+			msg->r_msg.param.buffer_tail =
+						r_msg->param.buffer_tail;
+			msg->r_msg.param.buffer_tail %= info->num_period[1];
+			spin_unlock_irqrestore(&info->lock[RX], flags);
+			info->callback[RX](info->callback_param[RX]);
+			break;
+		default:
+			dev_warn(&rpdev->dev, "unknown msg command\n");
+			break;
+		}
+		break;
+	case MSG_TYPE_B:
+		/* TYPE B is response msg */
+		memcpy(&info->r_msg, r_msg, sizeof(struct rpmsg_r_msg));
+		complete(&info->cmd_complete);
+		break;
+	default:
+		dev_warn(&rpdev->dev, "unknown msg type\n");
+		break;
+	}
+
+	return 0;
+}
+
+static int imx_audio_rpmsg_probe(struct rpmsg_device *rpdev)
+{
+	struct imx_audio_rpmsg *data;
+	int ret = 0;
+
+	dev_info(&rpdev->dev, "new channel: 0x%x -> 0x%x!\n",
+		 rpdev->src, rpdev->dst);
+
+	data = devm_kzalloc(&rpdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	dev_set_drvdata(&rpdev->dev, data);
+
+	/* Register platform driver for rpmsg routine */
+	data->rpmsg_pdev = platform_device_register_data(&rpdev->dev,
+							 IMX_PCM_DRV_NAME,
+							 PLATFORM_DEVID_NONE,
+							 NULL, 0);
+	if (IS_ERR(data->rpmsg_pdev)) {
+		dev_err(&rpdev->dev, "failed to register rpmsg platform.\n");
+		ret = PTR_ERR(data->rpmsg_pdev);
+	}
+
+	return ret;
+}
+
+static void imx_audio_rpmsg_remove(struct rpmsg_device *rpdev)
+{
+	struct imx_audio_rpmsg *data = dev_get_drvdata(&rpdev->dev);
+
+	if (data->rpmsg_pdev)
+		platform_device_unregister(data->rpmsg_pdev);
+
+	dev_info(&rpdev->dev, "audio rpmsg driver is removed\n");
+}
+
+static struct rpmsg_device_id imx_audio_rpmsg_id_table[] = {
+	{ .name	= "rpmsg-audio-channel" },
+	{ },
+};
+
+static struct rpmsg_driver imx_audio_rpmsg_driver = {
+	.drv.name	= "imx_audio_rpmsg",
+	.drv.owner	= THIS_MODULE,
+	.id_table	= imx_audio_rpmsg_id_table,
+	.probe		= imx_audio_rpmsg_probe,
+	.callback	= imx_audio_rpmsg_cb,
+	.remove		= imx_audio_rpmsg_remove,
+};
+
+static int __init imx_audio_rpmsg_init(void)
+{
+	return register_rpmsg_driver(&imx_audio_rpmsg_driver);
+}
+
+static void __exit imx_audio_rpmsg_exit(void)
+{
+	unregister_rpmsg_driver(&imx_audio_rpmsg_driver);
+}
+module_init(imx_audio_rpmsg_init);
+module_exit(imx_audio_rpmsg_exit);
+
+MODULE_DESCRIPTION("Freescale SoC Audio RPMSG interface");
+MODULE_AUTHOR("Shengjiu Wang <shengjiu.wang@nxp.com>");
+MODULE_ALIAS("platform:imx_audio_rpmsg");
+MODULE_LICENSE("GPL v2");