samples/rpmsg/rpmsg_client_sample.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Remote processor messaging - sample client driver
 *
 * Copyright (C) 2011 Texas Instruments, Inc.
 * Copyright (C) 2011 Google, Inc.
 *
 * Ohad Ben-Cohen <ohad@wizery.com>
 * Brian Swetland <swetland@google.com>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rpmsg.h>

#define MSG		"hello world!"

static int count = 100;
module_param(count, int, 0644);

struct instance_data {
	int rx_count;
};

static int rpmsg_sample_cb(struct rpmsg_device *rpdev, void *data, int len,
						void *priv, u32 src)
{
	int ret;
	struct instance_data *idata = dev_get_drvdata(&rpdev->dev);

	dev_info(&rpdev->dev, "incoming msg %d (src: 0x%x)\n",
		 ++idata->rx_count, src);

	print_hex_dump_debug(__func__, DUMP_PREFIX_NONE, 16, 1, data, len,
			     true);

	/* samples should not live forever */
	if (idata->rx_count >= count) {
		dev_info(&rpdev->dev, "goodbye!\n");
		return 0;
	}

	/* send a new message now */
	ret = rpmsg_send(rpdev->ept, MSG, strlen(MSG));
	if (ret)
		dev_err(&rpdev->dev, "rpmsg_send failed: %d\n", ret);

	return 0;
}

static int rpmsg_sample_probe(struct rpmsg_device *rpdev)
{
	int ret;
	struct instance_data *idata;
	ssize_t mtu, msg_len;

	dev_info(&rpdev->dev, "new channel: 0x%x -> 0x%x!\n",
					rpdev->src, rpdev->dst);

	idata = devm_kzalloc(&rpdev->dev, sizeof(*idata), GFP_KERNEL);
	if (!idata)
		return -ENOMEM;

	dev_set_drvdata(&rpdev->dev, idata);

	mtu = rpmsg_get_mtu(rpdev->ept);
	if (mtu < 0) {
		dev_warn(&rpdev->dev, "invalid rpmsg MTU size = %zd\n", mtu);
		return mtu;
	}

	dev_info(&rpdev->dev, "rpmsg MTU size = %zd\n", mtu);

	msg_len = strlen(MSG);
	/* make sure our message fits in a single rpmsg buffer */
	if (msg_len > mtu) {
		dev_err(&rpdev->dev,
			"message size %zd exceeds rpmsg MTU size %zd\n",
			msg_len, mtu);
		return -EMSGSIZE;
	}

	/* send a message to our remote processor */
	ret = rpmsg_send(rpdev->ept, MSG, msg_len);
	if (ret) {
		dev_err(&rpdev->dev, "rpmsg_send failed: %d\n", ret);
		return ret;
	}

	return 0;
}

static void rpmsg_sample_remove(struct rpmsg_device *rpdev)
{
	dev_info(&rpdev->dev, "rpmsg sample client driver is removed\n");
}

static struct rpmsg_device_id rpmsg_driver_sample_id_table[] = {
	{ .name	= "rpmsg-client-sample" },
	{ },
};
MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_sample_id_table);

static struct rpmsg_driver rpmsg_sample_client = {
	.drv.name	= KBUILD_MODNAME,
	.id_table	= rpmsg_driver_sample_id_table,
	.probe		= rpmsg_sample_probe,
	.callback	= rpmsg_sample_cb,
	.remove		= rpmsg_sample_remove,
};
module_rpmsg_driver(rpmsg_sample_client);

MODULE_DESCRIPTION("Remote processor messaging sample client driver");
MODULE_LICENSE("GPL v2");