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path: root/drivers/rpmsg/imx_rpmsg_tty.c
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Diffstat (limited to 'drivers/rpmsg/imx_rpmsg_tty.c')
-rw-r--r--drivers/rpmsg/imx_rpmsg_tty.c233
1 files changed, 233 insertions, 0 deletions
diff --git a/drivers/rpmsg/imx_rpmsg_tty.c b/drivers/rpmsg/imx_rpmsg_tty.c
new file mode 100644
index 00000000..14904c7
--- /dev/null
+++ b/drivers/rpmsg/imx_rpmsg_tty.c
@@ -0,0 +1,233 @@
+/*
+ * Copyright (C) 2015 Freescale Semiconductor, Inc.
+ *
+ * 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 <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/rpmsg.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
+#include <linux/virtio.h>
+
+/*
+ * 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_channel *rpdev;
+};
+
+static struct rpmsgtty_port rpmsg_tty_port;
+
+#define RPMSG_MAX_SIZE (512 - sizeof(struct rpmsg_hdr))
+#define MSG "hello world!"
+
+static void rpmsg_tty_cb(struct rpmsg_channel *rpdev, void *data, int len,
+ void *priv, u32 src)
+{
+ int space;
+ unsigned char *cbuf;
+ struct rpmsgtty_port *cport = &rpmsg_tty_port;
+
+ /* flush the recv-ed none-zero data to tty node */
+ if (len == 0)
+ return;
+
+ dev_dbg(&rpdev->dev, "msg(<- src 0x%x) len %d\n", src, len);
+
+ print_hex_dump(KERN_DEBUG, __func__, DUMP_PREFIX_NONE, 16, 1,
+ data, len, true);
+
+ spin_lock_bh(&cport->rx_lock);
+ space = tty_prepare_flip_string(&cport->port, &cbuf, len);
+ if (space <= 0) {
+ dev_err(&rpdev->dev, "No memory for tty_prepare_flip_string\n");
+ spin_unlock_bh(&cport->rx_lock);
+ return;
+ }
+
+ memcpy(cbuf, data, len);
+ tty_flip_buffer_push(&cport->port);
+ spin_unlock_bh(&cport->rx_lock);
+}
+
+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_channel *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, (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_channel *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, 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;
+
+ 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_channel *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-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");