1 // SPDX-License-Identifier: GPL-2.0
3  * Copyright (C) 2021 STMicroelectronics - All Rights Reserved
5  * The rpmsg tty driver implements serial communication on the RPMsg bus to makes
6  * possible for user-space programs to send and receive rpmsg messages as a standard
9  * The remote processor can instantiate a new tty by requesting a "rpmsg-tty" RPMsg service.
10  * The "rpmsg-tty" service is directly used for data exchange. No flow control is implemented yet.
16 #include <linux/rpmsg.h>
31 	int			id;	 /* TTY rpmsg index */
32 	struct rpmsg_device	*rpdev;	 /* rpmsg device */
37 	struct rpmsg_tty_port *cport = dev_get_drvdata(&rpdev->dev);  in rpmsg_tty_cb()
41 		return -EINVAL;  in rpmsg_tty_cb()
42 	copied = tty_insert_flip_string(&cport->port, data, len);  in rpmsg_tty_cb()
44 		dev_err_ratelimited(&rpdev->dev, "Trunc buffer: available space is %d\n", copied);  in rpmsg_tty_cb()
45 	tty_flip_buffer_push(&cport->port);  in rpmsg_tty_cb()
52 	struct rpmsg_tty_port *cport = idr_find(&tty_idr, tty->index);  in rpmsg_tty_install()
55 	tty->driver_data = cport;  in rpmsg_tty_install()
57 	port = tty_port_get(&cport->port);  in rpmsg_tty_install()
63 	tty_port_put(tty->port);  in rpmsg_tty_cleanup()
68 	return tty_port_open(tty->port, tty, filp);  in rpmsg_tty_open()
73 	return tty_port_close(tty->port, tty, filp);  in rpmsg_tty_close()
79 	struct rpmsg_tty_port *cport = tty->driver_data;  in rpmsg_tty_write()
84 	rpdev = cport->rpdev;  in rpmsg_tty_write()
86 	msg_max_size = rpmsg_get_mtu(rpdev->ept);  in rpmsg_tty_write()
94 	 * hung until a rpmsg buffer is available. In such case rpmsg_trysend returns -ENOMEM.  in rpmsg_tty_write()
96 	ret = rpmsg_trysend(rpdev->ept, (void *)buf, msg_size);  in rpmsg_tty_write()
98 		dev_dbg_ratelimited(&rpdev->dev, "rpmsg_send failed: %d\n", ret);  in rpmsg_tty_write()
107 	struct rpmsg_tty_port *cport = tty->driver_data;  in rpmsg_tty_write_room()
110 	size = rpmsg_get_mtu(cport->rpdev->ept);  in rpmsg_tty_write_room()
119 	tty_port_hangup(tty->port);  in rpmsg_tty_hangup()
139 		return ERR_PTR(-ENOMEM);  in rpmsg_tty_alloc_cport()
150 	cport->id = ret;  in rpmsg_tty_alloc_cport()
160 	idr_remove(&tty_idr, cport->id);  in rpmsg_tty_destruct_port()
174 	struct device *dev = &rpdev->dev;  in rpmsg_tty_probe()
182 	tty_port_init(&cport->port);  in rpmsg_tty_probe()
183 	cport->port.ops = &rpmsg_tty_port_ops;  in rpmsg_tty_probe()
185 	tty_dev = tty_port_register_device(&cport->port, rpmsg_tty_driver,  in rpmsg_tty_probe()
186 					   cport->id, dev);  in rpmsg_tty_probe()
189 		tty_port_put(&cport->port);  in rpmsg_tty_probe()
193 	cport->rpdev = rpdev;  in rpmsg_tty_probe()
197 	dev_dbg(dev, "New channel: 0x%x -> 0x%x: " RPMSG_TTY_NAME "%d\n",  in rpmsg_tty_probe()
198 		rpdev->src, rpdev->dst, cport->id);  in rpmsg_tty_probe()
205 	struct rpmsg_tty_port *cport = dev_get_drvdata(&rpdev->dev);  in rpmsg_tty_remove()
207 	dev_dbg(&rpdev->dev, "Removing rpmsg tty device %d\n", cport->id);  in rpmsg_tty_remove()
210 	tty_port_tty_hangup(&cport->port, false);  in rpmsg_tty_remove()
212 	tty_unregister_device(rpmsg_tty_driver, cport->id);  in rpmsg_tty_remove()
214 	tty_port_put(&cport->port);  in rpmsg_tty_remove()
218 	{ .name	= "rpmsg-tty" },
221 MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_tty_id_table);
224 	.drv.name	= KBUILD_MODNAME,
240 	rpmsg_tty_driver->driver_name = "rpmsg_tty";  in rpmsg_tty_init()
241 	rpmsg_tty_driver->name = RPMSG_TTY_NAME;  in rpmsg_tty_init()
242 	rpmsg_tty_driver->major = 0;  in rpmsg_tty_init()
243 	rpmsg_tty_driver->type = TTY_DRIVER_TYPE_CONSOLE;  in rpmsg_tty_init()
246 	rpmsg_tty_driver->init_termios = tty_std_termios;  in rpmsg_tty_init()
247 	rpmsg_tty_driver->init_termios.c_lflag &= ~(ECHO | ICANON);  in rpmsg_tty_init()
248 	rpmsg_tty_driver->init_termios.c_oflag &= ~(OPOST | ONLCR);  in rpmsg_tty_init()