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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>
*/
#include <linux/kernel.h>
#include <linux/serdev.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/poll.h>
#define SERPORT_ACTIVE 1
struct serport {
struct tty_port *port;
struct tty_struct *tty;
struct tty_driver *tty_drv;
int tty_idx;
unsigned long flags;
};
/*
* Callback functions from the tty port.
*/
static int ttyport_receive_buf(struct tty_port *port, const unsigned char *cp,
const unsigned char *fp, size_t count)
{
struct serdev_controller *ctrl = port->client_data;
struct serport *serport = serdev_controller_get_drvdata(ctrl);
int ret;
if (!test_bit(SERPORT_ACTIVE, &serport->flags))
return 0;
ret = serdev_controller_receive_buf(ctrl, cp, count);
dev_WARN_ONCE(&ctrl->dev, ret < 0 || ret > count,
"receive_buf returns %d (count = %zu)\n",
ret, count);
if (ret < 0)
return 0;
else if (ret > count)
return count;
return ret;
}
static void ttyport_write_wakeup(struct tty_port *port)
{
struct serdev_controller *ctrl = port->client_data;
struct serport *serport = serdev_controller_get_drvdata(ctrl);
struct tty_struct *tty;
tty = tty_port_tty_get(port);
if (!tty)
return;
if (test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) &&
test_bit(SERPORT_ACTIVE, &serport->flags))
serdev_controller_write_wakeup(ctrl);
wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
tty_kref_put(tty);
}
static const struct tty_port_client_operations client_ops = {
.receive_buf = ttyport_receive_buf,
.write_wakeup = ttyport_write_wakeup,
};
/*
* Callback functions from the serdev core.
*/
static int ttyport_write_buf(struct serdev_controller *ctrl, const unsigned char *data, size_t len)
{
struct serport *serport = serdev_controller_get_drvdata(ctrl);
struct tty_struct *tty = serport->tty;
if (!test_bit(SERPORT_ACTIVE, &serport->flags))
return 0;
set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
return tty->ops->write(serport->tty, data, len);
}
static void ttyport_write_flush(struct serdev_controller *ctrl)
{
struct serport *serport = serdev_controller_get_drvdata(ctrl);
struct tty_struct *tty = serport->tty;
tty_driver_flush_buffer(tty);
}
static int ttyport_write_room(struct serdev_controller *ctrl)
{
struct serport *serport = serdev_controller_get_drvdata(ctrl);
struct tty_struct *tty = serport->tty;
return tty_write_room(tty);
}
static int ttyport_open(struct serdev_controller *ctrl)
{
struct serport *serport = serdev_controller_get_drvdata(ctrl);
struct tty_struct *tty;
struct ktermios ktermios;
int ret;
tty = tty_init_dev(serport->tty_drv, serport->tty_idx);
if (IS_ERR(tty))
return PTR_ERR(tty);
serport->tty = tty;
if (!tty->ops->open || !tty->ops->close) {
ret = -ENODEV;
goto err_unlock;
}
ret = tty->ops->open(serport->tty, NULL);
if (ret)
goto err_close;
/* Bring the UART into a known 8 bits no parity hw fc state */
ktermios = tty->termios;
ktermios.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP |
INLCR | IGNCR | ICRNL | IXON);
ktermios.c_oflag &= ~OPOST;
ktermios.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
ktermios.c_cflag &= ~(CSIZE | PARENB);
ktermios.c_cflag |= CS8;
ktermios.c_cflag |= CRTSCTS;
tty_set_termios(tty, &ktermios);
set_bit(SERPORT_ACTIVE, &serport->flags);
tty_unlock(serport->tty);
return 0;
err_close:
tty->ops->close(tty, NULL);
err_unlock:
tty_unlock(tty);
tty_release_struct(tty, serport->tty_idx);
return ret;
}
static void ttyport_close(struct serdev_controller *ctrl)
{
struct serport *serport = serdev_controller_get_drvdata(ctrl);
struct tty_struct *tty = serport->tty;
clear_bit(SERPORT_ACTIVE, &serport->flags);
if (tty->ops->close)
tty->ops->close(tty, NULL);
tty_release_struct(tty, serport->tty_idx);
}
static unsigned int ttyport_set_baudrate(struct serdev_controller *ctrl, unsigned int speed)
{
struct serport *serport = serdev_controller_get_drvdata(ctrl);
struct tty_struct *tty = serport->tty;
struct ktermios ktermios = tty->termios;
ktermios.c_cflag &= ~CBAUD;
tty_termios_encode_baud_rate(&ktermios, speed, speed);
/* tty_set_termios() return not checked as it is always 0 */
tty_set_termios(tty, &ktermios);
return ktermios.c_ospeed;
}
static void ttyport_set_flow_control(struct serdev_controller *ctrl, bool enable)
{
struct serport *serport = serdev_controller_get_drvdata(ctrl);
struct tty_struct *tty = serport->tty;
struct ktermios ktermios = tty->termios;
if (enable)
ktermios.c_cflag |= CRTSCTS;
else
ktermios.c_cflag &= ~CRTSCTS;
tty_set_termios(tty, &ktermios);
}
static void ttyport_wait_until_sent(struct serdev_controller *ctrl, long timeout)
{
struct serport *serport = serdev_controller_get_drvdata(ctrl);
struct tty_struct *tty = serport->tty;
tty_wait_until_sent(tty, timeout);
}
static int ttyport_get_tiocm(struct serdev_controller *ctrl)
{
struct serport *serport = serdev_controller_get_drvdata(ctrl);
struct tty_struct *tty = serport->tty;
if (!tty->ops->tiocmget)
return -ENOTSUPP;
return tty->driver->ops->tiocmget(tty);
}
static int ttyport_set_tiocm(struct serdev_controller *ctrl, unsigned int set, unsigned int clear)
{
struct serport *serport = serdev_controller_get_drvdata(ctrl);
struct tty_struct *tty = serport->tty;
if (!tty->ops->tiocmset)
return -ENOTSUPP;
return tty->driver->ops->tiocmset(tty, set, clear);
}
static const struct serdev_controller_ops ctrl_ops = {
.write_buf = ttyport_write_buf,
.write_flush = ttyport_write_flush,
.write_room = ttyport_write_room,
.open = ttyport_open,
.close = ttyport_close,
.set_flow_control = ttyport_set_flow_control,
.set_baudrate = ttyport_set_baudrate,
.wait_until_sent = ttyport_wait_until_sent,
.get_tiocm = ttyport_get_tiocm,
.set_tiocm = ttyport_set_tiocm,
};
struct device *serdev_tty_port_register(struct tty_port *port,
struct device *parent,
struct tty_driver *drv, int idx)
{
const struct tty_port_client_operations *old_ops;
struct serdev_controller *ctrl;
struct serport *serport;
int ret;
if (!port || !drv || !parent)
return ERR_PTR(-ENODEV);
ctrl = serdev_controller_alloc(parent, sizeof(struct serport));
if (!ctrl)
return ERR_PTR(-ENOMEM);
serport = serdev_controller_get_drvdata(ctrl);
serport->port = port;
serport->tty_idx = idx;
serport->tty_drv = drv;
ctrl->ops = &ctrl_ops;
old_ops = port->client_ops;
port->client_ops = &client_ops;
port->client_data = ctrl;
ret = serdev_controller_add(ctrl);
if (ret)
goto err_reset_data;
dev_info(&ctrl->dev, "tty port %s%d registered\n", drv->name, idx);
return &ctrl->dev;
err_reset_data:
port->client_data = NULL;
port->client_ops = old_ops;
serdev_controller_put(ctrl);
return ERR_PTR(ret);
}
int serdev_tty_port_unregister(struct tty_port *port)
{
struct serdev_controller *ctrl = port->client_data;
struct serport *serport = serdev_controller_get_drvdata(ctrl);
if (!serport)
return -ENODEV;
serdev_controller_remove(ctrl);
port->client_ops = NULL;
port->client_data = NULL;
serdev_controller_put(ctrl);
return 0;
}
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