/* * Copyright (C) 2015-2016 Freescale Semiconductor, Inc. * Copyright (C) 2017 NXP * * derived from the omap-rpmsg implementation. * Remote processor messaging transport - tty driver * * The code contained herein is licensed under the GNU General Public * License. You may obtain a copy of the GNU General Public License * Version 2 or later at the following locations: * * http://www.opensource.org/licenses/gpl-license.html * http://www.gnu.org/copyleft/gpl.html */ #include #include #include #include #include #include #include #include /* * struct rpmsgtty_port - Wrapper struct for imx rpmsg tty port. * @port: TTY port data */ struct rpmsgtty_port { struct tty_port port; spinlock_t rx_lock; struct rpmsg_device *rpdev; }; static struct rpmsgtty_port rpmsg_tty_port; /* this needs to be less then (RPMSG_BUF_SIZE - sizeof(struct rpmsg_hdr)) */ #define RPMSG_MAX_SIZE 256 #define MSG "hello world!" static int rpmsg_tty_cb(struct rpmsg_device *rpdev, void *data, int len, void *priv, u32 src) { int copied; struct rpmsgtty_port *cport = &rpmsg_tty_port; struct tty_struct *tty = tty_port_tty_get(&cport->port); /* no one left to give data to, so sleep */ if (tty == NULL) { dev_dbg(&rpdev->dev, "waiting for readers, discard len %d\n", len); return -ENOTTY; } /* flush the recv-ed none-zero data to tty node */ if (len == 0) return 0; dev_dbg(&rpdev->dev, "msg(<- src 0x%x) len %d\n", src, len); print_hex_dump_debug(__func__, DUMP_PREFIX_NONE, 16, 1, data, len, true); spin_lock_bh(&cport->rx_lock); copied = tty_insert_flip_string(&cport->port, data, len); if (copied != len) dev_err_ratelimited(&rpdev->dev, "RX copy to tty layer failed\n"); tty_flip_buffer_push(&cport->port); spin_unlock_bh(&cport->rx_lock); return 0; } static struct tty_port_operations rpmsgtty_port_ops = { }; static int rpmsgtty_install(struct tty_driver *driver, struct tty_struct *tty) { return tty_port_install(&rpmsg_tty_port.port, driver, tty); } static int rpmsgtty_open(struct tty_struct *tty, struct file *filp) { return tty_port_open(tty->port, tty, filp); } static void rpmsgtty_close(struct tty_struct *tty, struct file *filp) { return tty_port_close(tty->port, tty, filp); } static int rpmsgtty_write(struct tty_struct *tty, const unsigned char *buf, int total) { int count, ret = 0; const unsigned char *tbuf; struct rpmsgtty_port *rptty_port = container_of(tty->port, struct rpmsgtty_port, port); struct rpmsg_device *rpdev = rptty_port->rpdev; if (NULL == buf) { pr_err("buf shouldn't be null.\n"); return -ENOMEM; } count = total; tbuf = buf; do { /* send a message to our remote processor */ ret = rpmsg_send(rpdev->ept, (void *)tbuf, count > RPMSG_MAX_SIZE ? RPMSG_MAX_SIZE : count); if (ret) { dev_err(&rpdev->dev, "rpmsg_send failed: %d\n", ret); return ret; } if (count > RPMSG_MAX_SIZE) { count -= RPMSG_MAX_SIZE; tbuf += RPMSG_MAX_SIZE; } else { count = 0; } } while (count > 0); return total; } static int rpmsgtty_write_room(struct tty_struct *tty) { /* report the space in the rpmsg buffer */ return RPMSG_MAX_SIZE; } static const struct tty_operations imxrpmsgtty_ops = { .install = rpmsgtty_install, .open = rpmsgtty_open, .close = rpmsgtty_close, .write = rpmsgtty_write, .write_room = rpmsgtty_write_room, }; static struct tty_driver *rpmsgtty_driver; static int rpmsg_tty_probe(struct rpmsg_device *rpdev) { int err; struct rpmsgtty_port *cport = &rpmsg_tty_port; dev_info(&rpdev->dev, "new channel: 0x%x -> 0x%x!\n", rpdev->src, rpdev->dst); /* * send a message to our remote processor, and tell remote * processor about this channel */ err = rpmsg_send(rpdev->ept, MSG, strlen(MSG)); if (err) { dev_err(&rpdev->dev, "rpmsg_send failed: %d\n", err); return err; } rpmsgtty_driver = tty_alloc_driver(1, TTY_DRIVER_UNNUMBERED_NODE); if (IS_ERR(rpmsgtty_driver)) return PTR_ERR(rpmsgtty_driver); rpmsgtty_driver->driver_name = "rpmsg_tty"; rpmsgtty_driver->name = "ttyRPMSG"; rpmsgtty_driver->major = TTYAUX_MAJOR; rpmsgtty_driver->minor_start = 3; rpmsgtty_driver->type = TTY_DRIVER_TYPE_CONSOLE; rpmsgtty_driver->init_termios = tty_std_termios; /* set default to no chracter echoing of the tty driver */ rpmsgtty_driver->init_termios.c_lflag = rpmsgtty_driver->init_termios.c_lflag & ~ECHO; tty_set_operations(rpmsgtty_driver, &imxrpmsgtty_ops); tty_port_init(&cport->port); cport->port.ops = &rpmsgtty_port_ops; spin_lock_init(&cport->rx_lock); cport->port.low_latency = cport->port.flags | ASYNC_LOW_LATENCY; err = tty_register_driver(rpmsgtty_driver); if (err < 0) { pr_err("Couldn't install rpmsg tty driver: err %d\n", err); goto error; } else pr_info("Install rpmsg tty driver!\n"); cport->rpdev = rpdev; return 0; error: tty_unregister_driver(rpmsgtty_driver); put_tty_driver(rpmsgtty_driver); tty_port_destroy(&cport->port); rpmsgtty_driver = NULL; return err; } static void rpmsg_tty_remove(struct rpmsg_device *rpdev) { struct rpmsgtty_port *cport = &rpmsg_tty_port; dev_info(&rpdev->dev, "rpmsg tty driver is removed\n"); tty_unregister_driver(rpmsgtty_driver); put_tty_driver(rpmsgtty_driver); tty_port_destroy(&cport->port); rpmsgtty_driver = NULL; } static struct rpmsg_device_id rpmsg_driver_tty_id_table[] = { { .name = "rpmsg-virtual-tty-channel" }, { .name = "rpmsg-openamp-demo-channel" }, { }, }; MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_tty_id_table); static struct rpmsg_driver rpmsg_tty_driver = { .drv.name = KBUILD_MODNAME, .drv.owner = THIS_MODULE, .id_table = rpmsg_driver_tty_id_table, .probe = rpmsg_tty_probe, .callback = rpmsg_tty_cb, .remove = rpmsg_tty_remove, }; static int __init init(void) { return register_rpmsg_driver(&rpmsg_tty_driver); } static void __exit fini(void) { unregister_rpmsg_driver(&rpmsg_tty_driver); } module_init(init); module_exit(fini); MODULE_AUTHOR("Freescale Semiconductor, Inc."); MODULE_DESCRIPTION("iMX virtio remote processor messaging tty driver"); MODULE_LICENSE("GPL v2");