drivers/tty/serdev/serdev-ttyport.c

   1 /*
   2  * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 and
   6  * only version 2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13 #include <linux/kernel.h>
  14 #include <linux/serdev.h>
  15 #include <linux/tty.h>
  16 #include <linux/tty_driver.h>
  17 #include <linux/poll.h>
  18
  19 #define SERPORT_ACTIVE          1
  20
  21 struct serport {
  22         struct tty_port *port;
  23         struct tty_struct *tty;
  24         struct tty_driver *tty_drv;
  25         int tty_idx;
  26         unsigned long flags;
  27 };
  28
  29 /*
  30  * Callback functions from the tty port.
  31  */
  32
  33 static int ttyport_receive_buf(struct tty_port *port, const unsigned char *cp,
  34                                 const unsigned char *fp, size_t count)
  35 {
  36         struct serdev_controller *ctrl = port->client_data;
  37         struct serport *serport = serdev_controller_get_drvdata(ctrl);
  38
  39         if (!test_bit(SERPORT_ACTIVE, &serport->flags))
  40                 return 0;
  41
  42         return serdev_controller_receive_buf(ctrl, cp, count);
  43 }
  44
  45 static void ttyport_write_wakeup(struct tty_port *port)
  46 {
  47         struct serdev_controller *ctrl = port->client_data;
  48         struct serport *serport = serdev_controller_get_drvdata(ctrl);
  49
  50         if (test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &port->tty->flags) &&
  51             test_bit(SERPORT_ACTIVE, &serport->flags))
  52                 serdev_controller_write_wakeup(ctrl);
  53
  54         wake_up_interruptible_poll(&port->tty->write_wait, POLLOUT);
  55 }
  56
  57 static const struct tty_port_client_operations client_ops = {
  58         .receive_buf = ttyport_receive_buf,
  59         .write_wakeup = ttyport_write_wakeup,
  60 };
  61
  62 /*
  63  * Callback functions from the serdev core.
  64  */
  65
  66 static int ttyport_write_buf(struct serdev_controller *ctrl, const unsigned char *data, size_t len)
  67 {
  68         struct serport *serport = serdev_controller_get_drvdata(ctrl);
  69         struct tty_struct *tty = serport->tty;
  70
  71         if (!test_bit(SERPORT_ACTIVE, &serport->flags))
  72                 return 0;
  73
  74         set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
  75         return tty->ops->write(serport->tty, data, len);
  76 }
  77
  78 static void ttyport_write_flush(struct serdev_controller *ctrl)
  79 {
  80         struct serport *serport = serdev_controller_get_drvdata(ctrl);
  81         struct tty_struct *tty = serport->tty;
  82
  83         tty_driver_flush_buffer(tty);
  84 }
  85
  86 static int ttyport_write_room(struct serdev_controller *ctrl)
  87 {
  88         struct serport *serport = serdev_controller_get_drvdata(ctrl);
  89         struct tty_struct *tty = serport->tty;
  90
  91         return tty_write_room(tty);
  92 }
  93
  94 static int ttyport_open(struct serdev_controller *ctrl)
  95 {
  96         struct serport *serport = serdev_controller_get_drvdata(ctrl);
  97         struct tty_struct *tty;
  98         struct ktermios ktermios;
  99
 100         tty = tty_init_dev(serport->tty_drv, serport->tty_idx);
 101         if (IS_ERR(tty))
 102                 return PTR_ERR(tty);
 103         serport->tty = tty;
 104
 105         if (tty->ops->open)
 106                 tty->ops->open(serport->tty, NULL);
 107         else
 108                 tty_port_open(serport->port, tty, NULL);
 109
 110         /* Bring the UART into a known 8 bits no parity hw fc state */
 111         ktermios = tty->termios;
 112         ktermios.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP |
 113                               INLCR | IGNCR | ICRNL | IXON);
 114         ktermios.c_oflag &= ~OPOST;
 115         ktermios.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
 116         ktermios.c_cflag &= ~(CSIZE | PARENB);
 117         ktermios.c_cflag |= CS8;
 118         ktermios.c_cflag |= CRTSCTS;
 119         tty_set_termios(tty, &ktermios);
 120
 121         set_bit(SERPORT_ACTIVE, &serport->flags);
 122
 123         tty_unlock(serport->tty);
 124         return 0;
 125 }
 126
 127 static void ttyport_close(struct serdev_controller *ctrl)
 128 {
 129         struct serport *serport = serdev_controller_get_drvdata(ctrl);
 130         struct tty_struct *tty = serport->tty;
 131
 132         clear_bit(SERPORT_ACTIVE, &serport->flags);
 133
 134         if (tty->ops->close)
 135                 tty->ops->close(tty, NULL);
 136
 137         tty_release_struct(tty, serport->tty_idx);
 138 }
 139
 140 static unsigned int ttyport_set_baudrate(struct serdev_controller *ctrl, unsigned int speed)
 141 {
 142         struct serport *serport = serdev_controller_get_drvdata(ctrl);
 143         struct tty_struct *tty = serport->tty;
 144         struct ktermios ktermios = tty->termios;
 145
 146         ktermios.c_cflag &= ~CBAUD;
 147         tty_termios_encode_baud_rate(&ktermios, speed, speed);
 148
 149         /* tty_set_termios() return not checked as it is always 0 */
 150         tty_set_termios(tty, &ktermios);
 151         return speed;
 152 }
 153
 154 static void ttyport_set_flow_control(struct serdev_controller *ctrl, bool enable)
 155 {
 156         struct serport *serport = serdev_controller_get_drvdata(ctrl);
 157         struct tty_struct *tty = serport->tty;
 158         struct ktermios ktermios = tty->termios;
 159
 160         if (enable)
 161                 ktermios.c_cflag |= CRTSCTS;
 162         else
 163                 ktermios.c_cflag &= ~CRTSCTS;
 164
 165         tty_set_termios(tty, &ktermios);
 166 }
 167
 168 static void ttyport_wait_until_sent(struct serdev_controller *ctrl, long timeout)
 169 {
 170         struct serport *serport = serdev_controller_get_drvdata(ctrl);
 171         struct tty_struct *tty = serport->tty;
 172
 173         tty_wait_until_sent(tty, timeout);
 174 }
 175
 176 static int ttyport_get_tiocm(struct serdev_controller *ctrl)
 177 {
 178         struct serport *serport = serdev_controller_get_drvdata(ctrl);
 179         struct tty_struct *tty = serport->tty;
 180
 181         if (!tty->ops->tiocmget)
 182                 return -ENOTSUPP;
 183
 184         return tty->driver->ops->tiocmget(tty);
 185 }
 186
 187 static int ttyport_set_tiocm(struct serdev_controller *ctrl, unsigned int set, unsigned int clear)
 188 {
 189         struct serport *serport = serdev_controller_get_drvdata(ctrl);
 190         struct tty_struct *tty = serport->tty;
 191
 192         if (!tty->ops->tiocmset)
 193                 return -ENOTSUPP;
 194
 195         return tty->driver->ops->tiocmset(tty, set, clear);
 196 }
 197
 198 static const struct serdev_controller_ops ctrl_ops = {
 199         .write_buf = ttyport_write_buf,
 200         .write_flush = ttyport_write_flush,
 201         .write_room = ttyport_write_room,
 202         .open = ttyport_open,
 203         .close = ttyport_close,
 204         .set_flow_control = ttyport_set_flow_control,
 205         .set_baudrate = ttyport_set_baudrate,
 206         .wait_until_sent = ttyport_wait_until_sent,
 207         .get_tiocm = ttyport_get_tiocm,
 208         .set_tiocm = ttyport_set_tiocm,
 209 };
 210
 211 struct device *serdev_tty_port_register(struct tty_port *port,
 212                                         struct device *parent,
 213                                         struct tty_driver *drv, int idx)
 214 {
 215         const struct tty_port_client_operations *old_ops;
 216         struct serdev_controller *ctrl;
 217         struct serport *serport;
 218         int ret;
 219
 220         if (!port || !drv || !parent)
 221                 return ERR_PTR(-ENODEV);
 222
 223         ctrl = serdev_controller_alloc(parent, sizeof(struct serport));
 224         if (!ctrl)
 225                 return ERR_PTR(-ENOMEM);
 226         serport = serdev_controller_get_drvdata(ctrl);
 227
 228         serport->port = port;
 229         serport->tty_idx = idx;
 230         serport->tty_drv = drv;
 231
 232         ctrl->ops = &ctrl_ops;
 233
 234         old_ops = port->client_ops;
 235         port->client_ops = &client_ops;
 236         port->client_data = ctrl;
 237
 238         ret = serdev_controller_add(ctrl);
 239         if (ret)
 240                 goto err_reset_data;
 241
 242         dev_info(&ctrl->dev, "tty port %s%d registered\n", drv->name, idx);
 243         return &ctrl->dev;
 244
 245 err_reset_data:
 246         port->client_data = NULL;
 247         port->client_ops = old_ops;
 248         serdev_controller_put(ctrl);
 249
 250         return ERR_PTR(ret);
 251 }
 252
 253 int serdev_tty_port_unregister(struct tty_port *port)
 254 {
 255         struct serdev_controller *ctrl = port->client_data;
 256         struct serport *serport = serdev_controller_get_drvdata(ctrl);
 257
 258         if (!serport)
 259                 return -ENODEV;
 260
 261         serdev_controller_remove(ctrl);
 262         port->client_ops = NULL;
 263         port->client_data = NULL;
 264         serdev_controller_put(ctrl);
 265
 266         return 0;
 267 }