serdev: add a tty port controller driver

Add a serdev controller driver for tty ports.

The controller is registered with serdev when tty ports are registered
with the TTY core. As the TTY core is built-in only, this has the side
effect of making serdev built-in as well.

Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-By: Sebastian Reichel <sre@kernel.org>
Tested-By: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serdev/Kconfig b/drivers/tty/serdev/Kconfig
index 3b6ecd1..cdc6b82 100644 (file)
--- a/drivers/tty/serdev/Kconfig
+++ b/drivers/tty/serdev/Kconfig
@@ -6,3 +6,11 @@ menuconfig SERIAL_DEV_BUS
        help
          Core support for devices connected via a serial port.
 
+if SERIAL_DEV_BUS
+
+config SERIAL_DEV_CTRL_TTYPORT
+       bool "Serial device TTY port controller"
+       depends on TTY
+       depends on SERIAL_DEV_BUS != m
+
+endif

diff --git a/drivers/tty/serdev/Makefile b/drivers/tty/serdev/Makefile
index 01a9b62..0cbdb94 100644 (file)
--- a/drivers/tty/serdev/Makefile
+++ b/drivers/tty/serdev/Makefile
@@ -1,3 +1,5 @@
 serdev-objs := core.o
 
 obj-$(CONFIG_SERIAL_DEV_BUS) += serdev.o
+
+obj-$(CONFIG_SERIAL_DEV_CTRL_TTYPORT) += serdev-ttyport.o

diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c
new file mode 100644 (file)
index 0000000..683320b
--- /dev/null
+++ b/drivers/tty/serdev/serdev-ttyport.c
@@ -0,0 +1,224 @@
+/*
+ * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#include <linux/kernel.h>
+#include <linux/serdev.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.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);
+
+       if (!test_bit(SERPORT_ACTIVE, &serport->flags))
+               return 0;
+
+       return serdev_controller_receive_buf(ctrl, cp, count);
+}
+
+static void ttyport_write_wakeup(struct tty_port *port)
+{
+       struct serdev_controller *ctrl = port->client_data;
+       struct serport *serport = serdev_controller_get_drvdata(ctrl);
+
+       if (!test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &port->tty->flags))
+               return;
+
+       if (test_bit(SERPORT_ACTIVE, &serport->flags))
+               serdev_controller_write_wakeup(ctrl);
+}
+
+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;
+
+       tty = tty_init_dev(serport->tty_drv, serport->tty_idx);
+       serport->tty = tty;
+
+       serport->port->client_ops = &client_ops;
+       serport->port->client_data = ctrl;
+
+       if (tty->ops->open)
+               tty->ops->open(serport->tty, NULL);
+       else
+               tty_port_open(serport->port, tty, NULL);
+
+       /* 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;
+}
+
+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 speed;
+}
+
+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 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,
+};
+
+struct device *serdev_tty_port_register(struct tty_port *port,
+                                       struct device *parent,
+                                       struct tty_driver *drv, int idx)
+{
+       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;
+
+       ret = serdev_controller_add(ctrl);
+       if (ret)
+               goto err_controller_put;
+
+       dev_info(&ctrl->dev, "tty port %s%d registered\n", drv->name, idx);
+       return &ctrl->dev;
+
+err_controller_put:
+       serdev_controller_put(ctrl);
+       return ERR_PTR(ret);
+}
+
+void 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;
+
+       serdev_controller_remove(ctrl);
+       port->client_ops = NULL;
+       port->client_data = NULL;
+       serdev_controller_put(ctrl);
+}

diff --git a/include/linux/serdev.h b/include/linux/serdev.h
index 3ac26c1..9519da6 100644 (file)
--- a/include/linux/serdev.h
+++ b/include/linux/serdev.h
@@ -238,4 +238,25 @@ static inline int serdev_device_write_room(struct serdev_device *sdev)
 
 #endif /* CONFIG_SERIAL_DEV_BUS */
 
+/*
+ * serdev hooks into TTY core
+ */
+struct tty_port;
+struct tty_driver;
+
+#ifdef CONFIG_SERIAL_DEV_CTRL_TTYPORT
+struct device *serdev_tty_port_register(struct tty_port *port,
+                                       struct device *parent,
+                                       struct tty_driver *drv, int idx);
+void serdev_tty_port_unregister(struct tty_port *port);
+#else
+static inline struct device *serdev_tty_port_register(struct tty_port *port,
+                                          struct device *parent,
+                                          struct tty_driver *drv, int idx)
+{
+       return ERR_PTR(-ENODEV);
+}
+static inline void serdev_tty_port_unregister(struct tty_port *port) {}
+#endif /* CONFIG_SERIAL_DEV_CTRL_TTYPORT */
+
 #endif /*_LINUX_SERDEV_H */