1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org> 4 */ 5 #include <linux/kernel.h> 6 #include <linux/serdev.h> 7 #include <linux/tty.h> 8 #include <linux/tty_driver.h> 9 #include <linux/poll.h> 10 11 #define SERPORT_ACTIVE 1 12 13 struct serport { 14 struct tty_port *port; 15 struct tty_struct *tty; 16 struct tty_driver *tty_drv; 17 int tty_idx; 18 unsigned long flags; 19 }; 20 21 /* 22 * Callback functions from the tty port. 23 */ 24 25 static int ttyport_receive_buf(struct tty_port *port, const unsigned char *cp, 26 const unsigned char *fp, size_t count) 27 { 28 struct serdev_controller *ctrl = port->client_data; 29 struct serport *serport = serdev_controller_get_drvdata(ctrl); 30 int ret; 31 32 if (!test_bit(SERPORT_ACTIVE, &serport->flags)) 33 return 0; 34 35 ret = serdev_controller_receive_buf(ctrl, cp, count); 36 37 dev_WARN_ONCE(&ctrl->dev, ret < 0 || ret > count, 38 "receive_buf returns %d (count = %zu)\n", 39 ret, count); 40 if (ret < 0) 41 return 0; 42 else if (ret > count) 43 return count; 44 45 return ret; 46 } 47 48 static void ttyport_write_wakeup(struct tty_port *port) 49 { 50 struct serdev_controller *ctrl = port->client_data; 51 struct serport *serport = serdev_controller_get_drvdata(ctrl); 52 struct tty_struct *tty; 53 54 tty = tty_port_tty_get(port); 55 if (!tty) 56 return; 57 58 if (test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) && 59 test_bit(SERPORT_ACTIVE, &serport->flags)) 60 serdev_controller_write_wakeup(ctrl); 61 62 wake_up_interruptible_poll(&tty->write_wait, POLLOUT); 63 64 tty_kref_put(tty); 65 } 66 67 static const struct tty_port_client_operations client_ops = { 68 .receive_buf = ttyport_receive_buf, 69 .write_wakeup = ttyport_write_wakeup, 70 }; 71 72 /* 73 * Callback functions from the serdev core. 74 */ 75 76 static int ttyport_write_buf(struct serdev_controller *ctrl, const unsigned char *data, size_t len) 77 { 78 struct serport *serport = serdev_controller_get_drvdata(ctrl); 79 struct tty_struct *tty = serport->tty; 80 81 if (!test_bit(SERPORT_ACTIVE, &serport->flags)) 82 return 0; 83 84 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); 85 return tty->ops->write(serport->tty, data, len); 86 } 87 88 static void ttyport_write_flush(struct serdev_controller *ctrl) 89 { 90 struct serport *serport = serdev_controller_get_drvdata(ctrl); 91 struct tty_struct *tty = serport->tty; 92 93 tty_driver_flush_buffer(tty); 94 } 95 96 static int ttyport_write_room(struct serdev_controller *ctrl) 97 { 98 struct serport *serport = serdev_controller_get_drvdata(ctrl); 99 struct tty_struct *tty = serport->tty; 100 101 return tty_write_room(tty); 102 } 103 104 static int ttyport_open(struct serdev_controller *ctrl) 105 { 106 struct serport *serport = serdev_controller_get_drvdata(ctrl); 107 struct tty_struct *tty; 108 struct ktermios ktermios; 109 int ret; 110 111 tty = tty_init_dev(serport->tty_drv, serport->tty_idx); 112 if (IS_ERR(tty)) 113 return PTR_ERR(tty); 114 serport->tty = tty; 115 116 if (!tty->ops->open || !tty->ops->close) { 117 ret = -ENODEV; 118 goto err_unlock; 119 } 120 121 ret = tty->ops->open(serport->tty, NULL); 122 if (ret) 123 goto err_close; 124 125 /* Bring the UART into a known 8 bits no parity hw fc state */ 126 ktermios = tty->termios; 127 ktermios.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | 128 INLCR | IGNCR | ICRNL | IXON); 129 ktermios.c_oflag &= ~OPOST; 130 ktermios.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN); 131 ktermios.c_cflag &= ~(CSIZE | PARENB); 132 ktermios.c_cflag |= CS8; 133 ktermios.c_cflag |= CRTSCTS; 134 tty_set_termios(tty, &ktermios); 135 136 set_bit(SERPORT_ACTIVE, &serport->flags); 137 138 tty_unlock(serport->tty); 139 return 0; 140 141 err_close: 142 tty->ops->close(tty, NULL); 143 err_unlock: 144 tty_unlock(tty); 145 tty_release_struct(tty, serport->tty_idx); 146 147 return ret; 148 } 149 150 static void ttyport_close(struct serdev_controller *ctrl) 151 { 152 struct serport *serport = serdev_controller_get_drvdata(ctrl); 153 struct tty_struct *tty = serport->tty; 154 155 clear_bit(SERPORT_ACTIVE, &serport->flags); 156 157 tty_lock(tty); 158 if (tty->ops->close) 159 tty->ops->close(tty, NULL); 160 tty_unlock(tty); 161 162 tty_release_struct(tty, serport->tty_idx); 163 } 164 165 static unsigned int ttyport_set_baudrate(struct serdev_controller *ctrl, unsigned int speed) 166 { 167 struct serport *serport = serdev_controller_get_drvdata(ctrl); 168 struct tty_struct *tty = serport->tty; 169 struct ktermios ktermios = tty->termios; 170 171 ktermios.c_cflag &= ~CBAUD; 172 tty_termios_encode_baud_rate(&ktermios, speed, speed); 173 174 /* tty_set_termios() return not checked as it is always 0 */ 175 tty_set_termios(tty, &ktermios); 176 return ktermios.c_ospeed; 177 } 178 179 static void ttyport_set_flow_control(struct serdev_controller *ctrl, bool enable) 180 { 181 struct serport *serport = serdev_controller_get_drvdata(ctrl); 182 struct tty_struct *tty = serport->tty; 183 struct ktermios ktermios = tty->termios; 184 185 if (enable) 186 ktermios.c_cflag |= CRTSCTS; 187 else 188 ktermios.c_cflag &= ~CRTSCTS; 189 190 tty_set_termios(tty, &ktermios); 191 } 192 193 static void ttyport_wait_until_sent(struct serdev_controller *ctrl, long timeout) 194 { 195 struct serport *serport = serdev_controller_get_drvdata(ctrl); 196 struct tty_struct *tty = serport->tty; 197 198 tty_wait_until_sent(tty, timeout); 199 } 200 201 static int ttyport_get_tiocm(struct serdev_controller *ctrl) 202 { 203 struct serport *serport = serdev_controller_get_drvdata(ctrl); 204 struct tty_struct *tty = serport->tty; 205 206 if (!tty->ops->tiocmget) 207 return -ENOTSUPP; 208 209 return tty->driver->ops->tiocmget(tty); 210 } 211 212 static int ttyport_set_tiocm(struct serdev_controller *ctrl, unsigned int set, unsigned int clear) 213 { 214 struct serport *serport = serdev_controller_get_drvdata(ctrl); 215 struct tty_struct *tty = serport->tty; 216 217 if (!tty->ops->tiocmset) 218 return -ENOTSUPP; 219 220 return tty->driver->ops->tiocmset(tty, set, clear); 221 } 222 223 static const struct serdev_controller_ops ctrl_ops = { 224 .write_buf = ttyport_write_buf, 225 .write_flush = ttyport_write_flush, 226 .write_room = ttyport_write_room, 227 .open = ttyport_open, 228 .close = ttyport_close, 229 .set_flow_control = ttyport_set_flow_control, 230 .set_baudrate = ttyport_set_baudrate, 231 .wait_until_sent = ttyport_wait_until_sent, 232 .get_tiocm = ttyport_get_tiocm, 233 .set_tiocm = ttyport_set_tiocm, 234 }; 235 236 struct device *serdev_tty_port_register(struct tty_port *port, 237 struct device *parent, 238 struct tty_driver *drv, int idx) 239 { 240 const struct tty_port_client_operations *old_ops; 241 struct serdev_controller *ctrl; 242 struct serport *serport; 243 int ret; 244 245 if (!port || !drv || !parent) 246 return ERR_PTR(-ENODEV); 247 248 ctrl = serdev_controller_alloc(parent, sizeof(struct serport)); 249 if (!ctrl) 250 return ERR_PTR(-ENOMEM); 251 serport = serdev_controller_get_drvdata(ctrl); 252 253 serport->port = port; 254 serport->tty_idx = idx; 255 serport->tty_drv = drv; 256 257 ctrl->ops = &ctrl_ops; 258 259 old_ops = port->client_ops; 260 port->client_ops = &client_ops; 261 port->client_data = ctrl; 262 263 ret = serdev_controller_add(ctrl); 264 if (ret) 265 goto err_reset_data; 266 267 dev_info(&ctrl->dev, "tty port %s%d registered\n", drv->name, idx); 268 return &ctrl->dev; 269 270 err_reset_data: 271 port->client_data = NULL; 272 port->client_ops = old_ops; 273 serdev_controller_put(ctrl); 274 275 return ERR_PTR(ret); 276 } 277 278 int serdev_tty_port_unregister(struct tty_port *port) 279 { 280 struct serdev_controller *ctrl = port->client_data; 281 struct serport *serport = serdev_controller_get_drvdata(ctrl); 282 283 if (!serport) 284 return -ENODEV; 285 286 serdev_controller_remove(ctrl); 287 port->client_ops = NULL; 288 port->client_data = NULL; 289 serdev_controller_put(ctrl); 290 291 return 0; 292 } 293